1,950 results on '"Ren, P."'
Search Results
2. Deformation, fracture, and energy evolution characteristics of coal‐rock under dynamic–static combined loading
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Wei Li, Zhizhen Zhang, Yeqi Teng, Hao Wang, Cao Man, Menghan Ren, Xiaoji Shang, Linming Dou, and Feng Gao
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constitutive model ,dynamic–static combined loading ,energy evolution ,LS‐DYNA ,rock mechanics ,Technology ,Science - Abstract
Abstract Deep coal‐rock formations are subjected to complex stress environments characterized by high static stresses and dynamic disturbances. To study the damage, fracture, and energy evolution characteristics of coal‐rock under dynamic–static combined loading, a new multiscale constitutive model for coal‐rock under dynamic–static combined loading is proposed based on micromechanics, and it is implemented into the LS‐DYNA solver. A numerical model of coal‐rock Split Hopkinson Pressure Bar under dynamic–static combined loading is established using LS‐DYNA, and research on the mechanical and energy evolution characteristics of coal‐rock under one‐dimensional and three‐dimensional dynamic–static combined loading is conducted. The results show that under one‐dimensional dynamic–static combined loading, with the increase of precompression, the dynamic peak stress linearly decreases while the combined peak stress linearly increases, and the dissipated energy of the specimen shows a decreasing trend. The fracture patterns of the coal‐rock specimen include internal shear fracture and external tensile fracture, and eventually, these two modes of fracture intersect to form macroscopic mesh cracks. As the axial pressure increases, the degree of specimen fragmentation gradually increases. Under three‐dimensional dynamic–static combined loading, with the increase of preconfining pressure, the stress–strain curve of the specimen will transition from “stress drop” to “stress rebound” after the peak. The peak stress increases with the increase of confining pressure, and the energy dissipation density of the specimen increases first and then decreases with the increase of confining pressure. With the increase of confining pressure, the hoop deformation of the specimen plays a constraining role, and the degree of specimen fracture gradually weakens, and the time of fracture occurrence gradually delays. The research results contribute to revealing the mechanical and energy mechanisms of rockburst disasters in deep coal mines.
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- 2024
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3. Selective CO2 Electroreduction to Multi-Carbon Products on Organic-Functionalized CuO Nanoparticles by Local Micro-Environment Modulation
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Shan Ren, Xi Cao, Qikui Fan, Zhimao Yang, Fei Wang, Xin Wang, Licheng Bai, and Jian Yang
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CO2 electroreduction to C2+ ,Neutral electrolyte ,Organic-functionalized CuO nanoparticles ,Local micro-environment modulation ,Technology - Abstract
Highlights Developing surface-functionalized catalysts with exceptional activity and selectivity for the electrocatalytic CO2RR to C2+ products under neutral electrolyte. A remarkable C2+ FE of nearly 90% at an unprecedented current density of 300 mA cm−2 and maintain high FE (> 80%) at the wide current density performance (100–600 mA cm−2) in neutral environments using a flow cell as well as MEA electrolyzer. Mechanical study reveals that reducing the coverage of coordinated K·H2O water increased the probability of intermediate reactants (CO) interacting with the surface, thereby promoting efficient C–C coupling and enhancing the yield of C2+ products.
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- 2024
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4. Performance Limits and Advancements in Single 2D Transition Metal Dichalcogenide Transistor
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Jing Chen, Ming-Yuan Sun, Zhen-Hua Wang, Zheng Zhang, Kai Zhang, Shuai Wang, Yu Zhang, Xiaoming Wu, Tian-Ling Ren, Hong Liu, and Lin Han
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Two-dimensional transistors ,Dimension limits ,Performance limits ,Memory devices ,Artificial synapses ,Technology - Abstract
Highlights The review provides a comprehensive summary of performance limits of the single two-dimensional transition metal dichalcogenide (2D-TMD) transistor. The review details the two logical expressions of the single 2D-TMD logic transistor, including current and voltage. The review demonstrates the two calculating methods for dynamic energy consumption of 2D synaptic devices.
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- 2024
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5. Interpenetrated Structures for Enhancing Ion Diffusion Kinetics in Electrochemical Energy Storage Devices
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Xinzhe Xue, Longsheng Feng, Qiu Ren, Cassidy Tran, Samuel Eisenberg, Anica Pinongcos, Logan Valdovinos, Cathleen Hsieh, Tae Wook Heo, Marcus A. Worsley, Cheng Zhu, and Yat Li
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Interpenetrated structure ,3D printing ,Electrochemical energy storage ,Ion diffusion length ,Inter-electrode distance ,Technology - Abstract
Highlights A new and compact device configuration was created with two interpenetrated, individually addressable electrodes, allowing precise control over the geometric features and interactions between the electrodes. The interpenetrated electrode design improves ion diffusion kinetics in electrochemical energy storage devices by shortening the ion diffusion length and reducing ion concentration inhomogeneity. The device with interpenetrated electrodes outperformed the traditional separate electrode configuration, enhancing both volumetric energy density and capacity retention rate.
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- 2024
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6. Nanomaterial-Based Repurposing of Macrophage Metabolism and Its Applications
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Tingting Meng, Danfeng He, Zhuolei Han, Rong Shi, Yuhan Wang, Bibo Ren, Cheng Zhang, Zhengwei Mao, Gaoxing Luo, and Jun Deng
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Immunomodulatory nanomaterial ,Macrophage polarization ,Macrophage metabolic reprogramming ,Immune engineering ,Technology - Abstract
Highlights A large-scale metabolic adaptation in M1-polarized macrophages compared with M2 macrophages, along with multiple altered metabolite parameters that can serve as potential targets, have been discussed. Nanomaterial-based repurposing of macrophage metabolism and its applications are systematically summarized and illustrated using representative examples. Potential challenges, additional information about future research objectives, and priorities of nanomaterial-based macrophage immunotherapy are highlighted.
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- 2024
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7. Effect of La Treatment on Inclusions in H13 Hot Work Die Steel
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Ren Ji, Yan Yun, Tian Jialong, Wang Lichao, Jiang Chenggang, Wang Lin, Jiang Zhouhua
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h13 hot work die steel; la treatment; inclusions; thermodynamic calculation ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Technology - Abstract
The effect of La treatment on the transformation of inclusions in H13 steel was investigated by subjecting H13 die steel to vacuum induction melting and subsequently treating the molten steel with La under an argon atmosphere protection.The results demonstrate that La has a beneficial effect on inclusions in H13 steel, the number of inclusions increases with the increase of La content, while the average size of inclusions initially decreases and then increases. The inclusions in H13 steel without the rare earth La additions are primarily Al₂O₃ and MnS. However, with a La content of 0.016% in H13 steel, the dominant inclusions shift to La2O2S. When the La content in H13 steel is 0.016%, the inclusions in the steel are mainly La2O2S;Furthermore, when the La content reaches 0.045% and 0.073%, the predominant inclusions in steel become LaP and La2O2S. Thermodynamic calculations show that the transformation process of La-treated inclusions is Al2O3→LaAlO3→La2O2S in molten steel at 1 600 ℃. During the solidification process, La2S3 is initially precipitated in the molten steel. As the temperature continues to decline, LaP begins to precipitate on the surface of La2S3 and La2O2S, ultimately forming the composite inclusions La2O2S-LaP and La2S3-LaP.
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- 2024
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8. Effect of La on Mould Wettability and Interfacial Reaction between CMSX-4 Single Crystal Alloy and Ceramic Mould
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Han Weihao, Yu Jianbo, Ren Zhongming
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la content; cmsx-4 single crystal alloy; wettability; interfacial reaction ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Technology - Abstract
In order to obtain high-quality rare earth containing single crystal blades, the effect of La content on the wettability and interface reaction between CMSX-4 single crystal alloy and ceramic mould was studied by the droplet method.The experimental results show that when the 90×10-6 La is added, the wetting angle between the alloy and the mould decreases slightly, and only Al reacts with SiO2 in the mould and the reaction product is Al2O3. When the La content in the alloy reaches 143×10-6, and the wetting angle between the alloy and the mould decreases significantly, and both La and Al in the alloy react with SiO2 in the mould. Subsequently the La content continue to increase, and the lanthanum aluminate compounds with different La and Al atomic ratios are precipitated at the interface, and the wetting angle changes little. It can be seen that in the present experitment 143×10-6 is the critical content of interfacial reaction of La in CMSX-4 single crystal alloy, and the reaction between La and SiO2 can improve the wettability of the alloy/mould system.
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- 2024
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9. Application of AgNPs in biomedicine: An overview and current trends
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Ren Yanjie, Zhang Yun, and Li Xiaobing
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silver nanoparticles ,synthesis ,characterization ,antimicrobial ,anticancer ,biomedical application ,dentistry ,toxicity ,Technology ,Chemical technology ,TP1-1185 ,Physical and theoretical chemistry ,QD450-801 - Abstract
Silver nanoparticles (AgNPs) can provide excellent, reliable, and effective solutions for anti-microbial, drug-loading, and other purposes due to their extraordinary physical, chemical, and biological characteristics. Different methods have been used in the synthesis and characterization of AgNPs, and AgNPs have been applied in various fields of biomedicine, including dentistry, oncology, diabetology, neurodegenerative disorders, and so on. However, the cytotoxicity of AgNPs has not been solved during their application, making them controversial. The aim of this review is to summarize the capabilities, synthesis, and characterization methods, and the application of AgNPs in various biomedicine fields. In addition, the toxicity of AgNPs is explicated, and the methods of enhancing the benefit properties and reducing the toxicity of AgNPs are demonstrated. In the end, the perspective of AgNPs’ research and application are proposed for the great potential in biomedicine contributing to human health.
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- 2024
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10. Working with a robot in hospital and long-term care homes: staff experience
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Ren, Lily Haopu, Wong, Karen Lok Yi, Wong, Joey, Kleiss, Sarah, Berndt, Annette, Mann, Jim, Hussein, Ali, Hu, Grace, Wong, Lily, Khong, Ruth, Fu, Jason, Ahmed, Nazia, Nolte, Julia, and Hung, Lillian
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- 2024
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11. Visual-motor integration in children with unilateral cerebral palsy: application of the computer-aided measure of visual-motor integration
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Huang, Wen-Feng, Chen, Ren-Yu, Wang, Tien-Ni, Chuang, Po-Ya, Shieh, Jeng-Yi, and Chen, Hao-Ling
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- 2024
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12. Application Model of Hyperspectral Technology Based on Novel Spectral Indices for Salinity Assessment in Soil Heritage Sites
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F. Liu and Y. Ren
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Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Applied optics. Photonics ,TA1501-1820 - Abstract
The Dunhuang murals are a precious treasure of China's cultural heritage, yet they have long been affected by salt damage. Traditional methods for detecting salt content are costly, inefficient, and may cause physical harm to the murals. Among current techniques for measuring salt content in murals, hyperspectral remote sensing technology offers a non-invasive , circumventing issues of high costs, low efficiency. Building on this, our study developed a high-spectral feature inversion model for mural phosphate content using Fractional Order Differentiation (FOD), a novel three-band spectral index, and Partial Least Squares Regression (PLSR) algorithm. The specific research contents include: 1) Exploring the absorption mechanism of phosphates and their characteristic bands, combined with the optimal spectral index to construct a univariate linear regression model, providing a basis for rapid quantitative measurement of mural phosphate content. 2) By comparing the accuracy of the PSR and PNDI spectral indices based on the linear regression model, the first six orders of the highest accuracy spectral index were selected as the optimal three-band spectral index combination, used as explanatory variables, with mural plaster electrical conductivity as the response variable, employing the PLSR method to construct the mural phosphate content high-spectral feature inversion model. The study's findings include: 1) By comparing the outcomes of different orders of fractional differentiation, it was found that the model performance reached its optimum at a 0.3 order of differentiation for both PSR and PNDI data, with a determination coefficient (R2) of 0.728. 2) Utilizing PLSR, this study employed the previously determined optimal six-order three-band spectral index combination as explanatory variables, with salt content as the response variable, successfully constructing the high-spectral feature inversion model for mural phosphate content with a determination coefficient (R2) of 0.815. This provides an effective technical means for monitoring the salt damage conditions of precious cultural heritage such as murals.
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- 2024
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13. A Novel Hyperspectral Salt Assessment Model for Weathering in Architectural Ruins
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Y. Ren and F. Liu
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Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Applied optics. Photonics ,TA1501-1820 - Abstract
The Dunhuang murals, a significant part of Chinese heritage, have suffered deterioration primarily due to environmental and chemical factors, notably salt damage. This study proposes a sophisticated method that synergizes Fractional Order Differentiation (FOD) and Partial Least Squares Regression (PLSR) to accurately invert the phosphate content in the Mural Plaster of the Dunhuang paintings. The focal points of the research include: 1) To address the issue of information loss and reduced modeling precision caused by integer order differentiation algorithms, the FOD method is employed for preprocessing hyperspectral data. This approach ensures the fine spectral differences in the phosphate content of the Mural Plaster are precisely captured, 2) Utilizing PLSR, the study models the spectral bands identified at a significance level of 0.01 with measured conductivity values, thereby enabling the precise prediction of the phosphate content in the murals. The research outcomes reveal: 1) The FOD method can elucidate the nonlinear characteristics and variation patterns of the mural samples in the hyperspectral curve.As the order increases from zero to two, the number of spectral bands meeting the 0.01 significance test initially decreases and then increases. The highest absolute value of the positive correlation coefficient is observed at 1.9 orders, corresponding to the 2077 nm band, 2) For predicting the phosphate content in the murals, the model at 1.9 orders is most suitable for inversion. This model, after cross-validation, achieves a maximum R2 value of 0.783. This study created an efficient FOD-based model for estimating phosphate in mural plasters.
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- 2024
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14. A Survey on the Use of Intelligent Physical Service Robots for Elderly or Disabled Bedridden People at Home
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Wei Wang, Weihe Ren, Mengjia Li, and Pingping Chu
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intelligent physical service robots ,elderly people ,disabled people ,bedridden disabled elderly people ,home care ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Artificial Intelligence (AI) and robotic technologies have been applied in healthcare sectors for many years. Along with the ageing trend rising globally, the use of AI and intelligent service robots in home care for elderly or disabled bedridden people has generated considerable attention. A robot that can physically assist care-workers and the elderly or disabled bedridden people in daily activities may help ease care-workers’ burden and help older people live independently for longer with higher quality of life. This survey gives a comprehensive overview in the latest AI and robotic technologies applications in elderly care, providing a detailed analysis on the current products in the market, and discusses the problems and the future trend in this topic.
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- 2024
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15. Effectivity of Telemonitoring Toward Quality of Life in Patients with Chronic Obstructive Pulmonary Disease (COPD): A Systematic Review and Meta-Analysis
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Ananda Pipphali Vidya, Jansen Jayadi, Karen Elliora Utama, Kenneth Ren, Aditya Wirawan, and Nyityasmono Tri Nugroho
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copd ,mental health ,quality of life ,technology ,telemonitoring ,Medicine - Abstract
Introduction: Chronic obstructive pulmonary disorder (COPD) is the third-leading cause of death worldwide. COPD treatment is essential to manage and attenuate the progression of symptoms. Home-based telemonitoring interventions showed several promises in increasing COPD patients' quality of life (QoL) and outcomes. However, various results were obtained in recent studies, making a secondary research presence needed to establish clear risks and benefits. This study aimed to analyze the effect of telemonitoring on QoL among COPD patients. Methods: This study used the Preferred Reporting Items of Systematic Review and Meta-Analysis (PRISMA) reporting guidelines on several databases from February until April 2023. We performed screening and selection, followed by data extraction and quantitative analysis with Review Manager 5.4 Software. The risk of bias assessment was performed using the RoB 2.0 Cochrane tool. Results: Ten randomized controlled trials (RCTs), mostly low-risk of bias, were included. We found a reduction in Saint George's Respiratory Questionnaire (SGRQ) score (mean difference (MD) -1.13 [95% CI -4.23, 1.97; p = 0.47]) and Hospital Anxiety and Depression Scale (HADS) for anxiety (MD-0.16 [95% Cl -0.96, 0.63; p = 0.69]). There was no significant effect of HADS on depression and EuroQol-5 Dimension (EQ-5D). Conclusion: This study suggests that telemonitoring improves QoL in COPD patients, especially for SGRQ and HADS anxiety scores. We suggest a larger number of studies to evaluate the effect of telemonitoring on depression and anxiety. We also encourage the integration of telemedicine with the present care system to achieve the best beneficial outcome for patients.
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- 2024
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16. Effect of Different Ga Contents on the Acid and Alkaline Resistance of New SnInAg Lead-Free Solder Alloy
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REN Pengkai, XU Dongxia, CAO Fulei, CHU Yadong, ZHANG Hongxia
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lead -free solder;sn -in -ag alloy;ga;corrosion resistance ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Technology - Abstract
In order to improve the corrosion resistance of Sn-11In-1.5Ag lead-free solder alloy solder, the corrosion behavior of Sn-11In-1.5Ag-xGa(x=0, 0.1, 0.3, 0.5, 0.7, mass fraction, %) solder alloy in a corrosive environment was studied by weight loss method and electrochemical experiments. In addition, the surface morphologies of Sn-11in-1.5Ag-xGa solder alloy were observed by scanning electron microscopy(SEM), and the corrosion products on the solder surface were characterized by X-ray diffraction(XRD). Results showed that whether in acidic or alkaline solutions, the addition of Ga could improve the corrosion resistance of Sn-11In-1.5Ag solder alloy. With the increase of Ga content, the corrosion resistance of solder was enhanced. For solder alloys with the same composition, their corrosion resistance in alkaline solution was better than that in acid solution. Besides, SEM observation showed that adding Ga into Sn-11In-1.5Ag alloy could significantly reduce the corrosion degree of solder, and XRD analysis disclosed that the corrosion products of solder alloys in acidic and alkaline solutions were the same, both of which were In2O3.
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- 2024
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17. An automatic Q-factor matching method for eliminating 77% of the ZRO of a MEMS vibratory gyroscope in rate mode
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Jingbo Ren, Tong Zhou, Yi Zhou, Yixuan Li, and Yan Su
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Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Abstract Mismatching quality factors (Q-factors) is one of the main factors causing zero-rate output (ZRO) in degenerate (DE) Micro-Electro-Mechanical Systems (MEMS) vibratory gyroscopes. To eliminate the ZRO of the DE MEMS gyroscope, this study introduces a method for real-time identification and automatic matching of Q-factors in rate mode. By leveraging the vibration characteristics of the DE MEMS vibratory gyroscope in rate mode, dedicated online test methods are designed to determine the Q-factors for both the drive and sense modes, enabling online identification of the Q-factor mismatching. Furthermore, an automatic Q-factor matching system is designed utilizing the mechanical-thermal dissipation mechanism of the resistive damper. The effectiveness of this proposed method is validated through simulations and experiments conducted on a MEMS disk resonator gyroscope (DRG). The results show a measurement error within 4% for Q-factor identification, and automatic Q-factor matching effectively reduces the ZRO by 77%. Employing this automatic Q-factor matching method successfully reduces the ZRO that is caused by the mismatching of Q-factors in the MEMS DRG from 0.11°/s to 0.025°/s and improves the bias instability (BI) from 0.40°/s to 0.19°/s.
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- 2024
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18. Co-production of 1,3-propanediol and phage phiKpS2 from the glycerol fermentation by Klebsiella pneumoniae
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Suyang Duan, Zhirong Zhang, Xiaoli Wang, Yaqin Sun, Yuesheng Dong, Lina Ren, Lili Geng, and Zhilong Xiu
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Klebsiella pneumonia ,1,3-Propanediol ,Bacteriophage ,Co-production ,Salting-out extraction ,Technology ,Chemical technology ,TP1-1185 ,Biotechnology ,TP248.13-248.65 - Abstract
Abstract As an alternative to antibiotics in response to antimicrobial-resistant infections, bacteriophages (phages) are garnering renewed interest in recent years. However, the massive preparation of phage is restricted using traditional pathogens as host cells, which incurs additional costs and contamination. In this study, an opportunistic pathogen, Klebsiella pneumoniae used to convert glycerol to 1,3-propanediol (1,3-PDO), was reused to prepare phage after fermentation. The phage infection showed that the fed-batch fermentation broth containing 71.6 g/L 1,3-PDO can be directly used for preparation of phage with a titer of 1 × 108 pfu/mL. Then, the two-step salting-out extraction was adopted to remove most impurities, e.g. acetic acid (93.5%), ethanol (91.5%) and cells (99.4%) at the first step, and obtain 1,3-PDO (56.6%) in the top phase as well as phage (97.4%) in the middle phase at the second step. This integrated process provides a cheap and environment-friendly manner for coproduction of 1,3-PDO and phage. Graphical abstract
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- 2024
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19. Study on the Corrosion Behavior and Inhibitor Protection in Reclaimed Water Pipelines of Steel Enterprises
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LIU Yucheng, WU Wei, DU Zaihui, LI Ren, RUAN Min, HE Fang, YAN Xiaozhong
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carbon steel ,corrosion inhibitor ,reclaimed water system ,corrosion rate ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Technology - Abstract
For the corrosion problem within the reclaimed water transport pipelines of a steel company in Hunan, water samples from typical reclaimed water sources were collected for water quality analysis. The corrosion behavior of the reclaimed water transport pipelines was systematically investigated through hanging plate tests, microbial culture counting, electrochemical testing, scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD). Moreover, the corrosion inhibitory effects of hydroxyethylidene diphosphonic acid(HEDP), 2-Phosphonobutane-1,2,4-Tricarboxylic Acid(PBTCA) and polyaspartic acid(PASP) were examined. Results showed that the quality of reclaimed water was significantly impacted by biological dephenolization wastewater, blast furnace drainage, total drainage in the direction of five meters and drainage from three water stations. The passivation film on the surface of reclaimed water pipelines was destroyed by the action of Cl- and SO42- in the water, while iron bacteria and sulfate-reducing bacteria promoted corrosion, resulting in the formation of Fe(OH)3 and FeS. After the addition of HEDP and PBTCA corrosion inhibitors, a decrease in the thickness of the corrosion layer was observed, and the corrosion rate fell below the national standard. Following the addition of PASP, the corrosion products on the surface of the hanging plate were loose and porous siderite. In the low-frequency impedance region, Warburg impedance characteristics were displayed, and the corrosion inhibition rate was only 3.9%.
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- 2024
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20. Research on automatic grading model of HSK reading texts based on supervised learning
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Meng REN and Fangwei WANG
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natural language processing ,supervised learning ,hsk reading text ,readability feature ,grading model ,Technology - Abstract
Aiming at the problem that there are few effective reference standards and analysis tools available in classifying and grading Hanyu Shuiping Kaoshi(HSK) reading materials, with HSK reading texts in the past years as study object, the text readability features were extracted, and nine supervised learning algorithms, such as support vector machine, decision tree and extreme gradient enhancement, etc., were employed to build a model that could automatically classify self-selected text to the corresponding HSK level. Multiple indicators such as accuracy and AUC were adopted to evaluate the grading effect of each model, and the best model was chosen to design an online tool. The results show that supervised learning has high performance in analyzing and grading HSK reading materials. Among the nine supervised learning models, extreme gradient enhancement is the best, with an accuracy of 0.913 and an AUC of 0.994. The grading model and online tool can grade HSK self-selected texts with high accuracy, help users select texts pertinently and improve learning efficiency.
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- 2024
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21. Research on axial compression performance test and bearing capacity calculation method of newly assembled hollow lattice wallboard
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Yunlin Liu, Shangwei Huo, Zhixin Wu, Dingguo Yang, Ke Ren, Jianhua Liu, and Riguang Wang
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lattice wallboard ,axial compression test ,axial compression performance ,influence of eccentric compression ,bearing capacity ,Technology - Abstract
With the great development of the construction industry, prefabricated building components have been greatly developed. To study the compressive performance of the new wallboard, the axial compression performance test of six full-scale new lattice wallboards was carried out in this paper. The failure mode, axial pressure-displacement relationship curve, axial compression bearing capacity, and axial pressure-strain relationship of the wallboard were obtained through the experiments. This reveals the influence of the thickness of the concrete surface and the number of ribs on the performance of the wallboard. The test results show that the ultimate bearing capacity of the specimen increases with the increase of the thickness of the concrete surface layer with the same number of ribs. Specimen DW -30 increased by 4% over DW -20 and DW -50 increased by 41.6% over DW -30. The ultimate bearing capacity of the three-ribbed specimens was higher than that of the two-ribbed specimens for the same concrete face thickness, about 1.11 times that of the two-ribbed specimens. The concrete facing thickness and the number of ribs have a restraining effect on the deformation of the wallboard. Additionally, the calculation formula of axial bearing capacity of type latticed wallboard considering the influence of eccentric compression was proposed, which can provide a reference for engineering calculation.
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- 2024
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22. Experimental study on municipal solid waste incineration ash micro-powder as concrete admixture
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Hanghang Li, Dongsheng Shi, Hao Li, and Dongdong Ren
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mswi ash micro-powder ,concrete ,mechanical property ,microhardness ,lca ,Technology ,Chemical technology ,TP1-1185 - Abstract
To improve the utilization rate of municipal solid waste incineration (MSWI) ash and achieve resource recycling, this article conducted research on grinding MSWI ash into fine powder for use as a concrete admixture. Initially, the physical and chemical properties of the MSWI ash micro-powder were tested. Subsequently, different amounts of MSWI ash powder concrete were prepared. The macro and micro properties of the concrete were then tested. Finally, a life cycle assessment was utilized to evaluate and compare ordinary concrete with MSWI ash micro-powder concrete. The results indicate that the chemical composition of the MSWI ash micro-powder is similar to that of cement clinker. It exhibits potential hydraulicity and a slow hydration reaction, making it an active admixture suitable for concrete raw materials. With the increasing proportion of MSWI ash micro-powder, the rate of hydration reaction in concrete slows down, resulting in decreased mechanical properties. The microhardness value of the hardened cement paste in MSWI ash micro-powder concrete is lower than that of ordinary concrete. Moreover, the addition of MSWI ash micro-powder helps mitigate the environmental impact of concrete in terms of non-biological energy loss and CO2 emissions.
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- 2024
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23. Editorial: Multifunctional, flexible, polymeric materials with controlled nanostructures
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Lulu Ren, Zhengxing Peng, Junpyo Kwon, and He Li
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polymeric materials ,composites ,multifunctional ,structure-properties correlations ,nanostructures ,Technology - Published
- 2024
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24. CO2 derived ABA triblock all-polycarbonate thermoplastic elastomer with ultra-high elastic recovery
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Yansong Ren, Tianyun Zhang, Shuanjin Wang, Dongmei Han, Sheng Huang, Hui Guo, Min Xiao, and Yuezhong Meng
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Biodegradable ,Thermoplastic elastomer ,Elastic recovery ,Metal-free ,CO2 utilization ,Triblock polycarbonate ,Technology - Abstract
Although triblock polycarbonate thermoplastic elastomers (TPEs) have recently attracted great interests due to their biodegradability, insufficient attentions have been paid to improving the elastomeric properties. Through a tandem reaction strategy involving CO2 / allyl glycidyl ether (AGE) / cyclohexene oxide (CHO), poly(cyclohexene carbonate)-b-poly(allyl glycidyl ether carbonate)-b-poly(cyclohexene carbonate) (PCAC) is successfully synthesized using a metal-free Lewis acid-base pair catalyst. The synthesized PCACs are pure well-defined ABA triblock all-polycarbonate, which is supported by 1H NMR, gel permeation chromatography (GPC), and diffusion-ordered spectroscopy (DOSY). A simple modification by grafting alkylthiol chains to PCAC results in excellent TPEs named PCAC-g-S-CaH2a+1 (PCASaC). The synthesized TPEs are characterized by atomic force microscopy (AFM), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and mechanical test. They demonstrate a semi-network and semi-domain phase separation structure, wide service temperature range, good strength, high elongation, and extremely high elastic recovery properties. This low-cost, biodegradable, high-performance TPE shows great potential for applications in biomedical, wearable products, sports equipment, and other fields.
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- 2024
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25. Tracing the origins of the STEM gender gap: The contribution of childhood spatial skills.
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Tian, Jing, Ren, Kexin, Newcombe, Nora, Weinraub, Marsha, Vandell, Deborah, and Gunderson, Elizabeth
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STEM major ,achievement ,gender differences ,motivation ,spatial skills ,Adult ,Child ,Female ,Humans ,Career Choice ,Engineering ,Motivation ,Sex Factors ,Technology ,Science - Abstract
Despite some gains, women continue to be underrepresented in many science, technology, engineering, and math (STEM) fields. Using a national longitudinal dataset of 690 participants born in 1991, we tested whether spatial skills, measured in middle childhood, would help explain this gender gap. We modeled the relation between 4th-grade spatial skills and STEM majors while simultaneously accounting for competing cognitive and motivational mechanisms. Strong spatial skills in 4th grade directly increased the likelihood of choosing STEM college majors, above and beyond math achievement and motivation, verbal achievement and motivation, and family background. Additionally, 4th-grade spatial skills indirectly predicted STEM major choice via math achievement and motivation in the intervening years. Further, our findings suggest that gender differences in 4th-grade spatial skills contribute to womens underrepresentation in STEM majors. RESEARCH HIGHLIGHTS: Using a national longitudinal dataset, we found 4th-grade spatial skills directly predicted STEM college major choice after accounting for multiple cognitive and motivational mechanisms. Strong spatial skills in 4th grade also elevated STEM major choice via enhanced math achievement and motivation in the intervening years. Gender differences in 4th-grade spatial skills contributed to womens underrepresentation in STEM college majors.
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- 2023
26. ROS Balance Autoregulating Core–Shell CeO2@ZIF-8/Au Nanoplatform for Wound Repair
- Author
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Xi Zhou, Quan Zhou, Zhaozhi He, Yi Xiao, Yan Liu, Zhuohang Huang, Yaoji Sun, Jiawei Wang, Zhengdong Zhao, Xiaozhou Liu, Bin Zhou, Lei Ren, Yu Sun, Zhiwei Chen, and Xingcai Zhang
- Subjects
Metal–organic framework (MOF) ,Reactive oxygen species (ROS) ,Cerium dioxide ,Au nanoparticles ,Wound healing ,Technology - Abstract
Highlights The innovation of this work mainly lies in the auto-regulation of reactive oxygen species (ROS) balance effective by combination of ROS antibacterial and ROS scavenging anti-inflammatory functions with a core–shell nanoplatform (CeO2@ZIF-8/Au), which can not only achieve high antibacterial efficiency, but also promote wound healing, and provide a new idea for the nano-catalytic system in the field of wound healing of bacterial infection.
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- 2024
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27. Boosting Hydrogen Storage Performance of MgH2 by Oxygen Vacancy-Rich H-V2O5 Nanosheet as an Excited H-Pump
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Li Ren, Yinghui Li, Zi Li, Xi Lin, Chong Lu, Wenjiang Ding, and Jianxin Zou
- Subjects
Hydrogen storage ,MgH2 ,V2O5 nanosheets ,Oxygen vacancies ,VH2 ,Technology - Abstract
Highlights Graphene-like 2D V2O5 nanosheets rich in oxygen vacancies are designed as multi-functional catalysts to fabricate MgH2-H-V2O5 composites. Hydrogen release starts from 185 °C and capacity retention is as high as 99% after 100 cycles at 275 °C. The composites present rapid kinetics and impressive hydrogen absorption capability at near room temperature. The oxygen vacancies could directly enhance kinetics of MgH2 while indirectly exciting “hydrogen pump” effect of VH2/V.
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- 2024
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28. Recent advances in the biosynthesis and industrial biotechnology of Gamma-amino butyric acid
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Ripon Baroi Milon, Pengchen Hu, Xueqiong Zhang, Xuechao Hu, and Lujing Ren
- Subjects
Gamma-aminobutyric acid ,Biosynthesis ,Microbial production ,Fermentation optimization ,Metabolic pathways ,Technology ,Chemical technology ,TP1-1185 ,Biotechnology ,TP248.13-248.65 - Abstract
Abstract GABA (Gamma-aminobutyric acid), a crucial neurotransmitter in the central nervous system, has gained significant attention in recent years due to its extensive benefits for human health. The review focused on recent advances in the biosynthesis and production of GABA. To begin with, the investigation evaluates GABA-producing strains and metabolic pathways, focusing on microbial sources such as Lactic Acid Bacteria, Escherichia coli, and Corynebacterium glutamicum. The metabolic pathways of GABA are elaborated upon, including the GABA shunt and critical enzymes involved in its synthesis. Next, strategies to enhance microbial GABA production are discussed, including optimization of fermentation factors, different fermentation methods such as co-culture strategy and two-step fermentation, and modification of the GABA metabolic pathway. The review also explores methods for determining glutamate (Glu) and GABA levels, emphasizing the importance of accurate quantification. Furthermore, a comprehensive market analysis and prospects are provided, highlighting current trends, potential applications, and challenges in the GABA industry. Overall, this review serves as a valuable resource for researchers and industrialists working on GABA advancements, focusing on its efficient synthesis processes and various applications, and providing novel ideas and approaches to improve GABA yield and quality. Graphical Abstract
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- 2024
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29. High-throughput and simultaneous inertial separation of tumor cells and clusters from malignant effusions using spiral-contraction-expansion channels
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Zhixian Zhu, Hui Ren, Dan Wu, Zhonghua Ni, and Nan Xiang
- Subjects
Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Abstract Tumor cell clusters are regarded as critical factors in cancer pathophysiology, and increasing evidence of their higher treatment resistance and metastasis compared to single tumor cells has been obtained. However, existing cell separation methods that are designed for single tumor cells cannot be used to simultaneously purify tumor cell clusters. To address this problem, we demonstrated a microfluidic approach for the high-throughput, continuous-flow ternary separation of single tumor cells, tumor cell clusters, and WBCs from clinical pleural or abdominal effusions by coupling slanted spiral channels and periodic contraction-expansion arrays. We first systematically explored the influence of particle size and flow rate on particle focusing. The separation performance indicated that 94.0% of WBCs were removed and more than 97% of MDA-MB-231 tumor cells were recovered at a high flow rate of 3500 µL/min. Moreover, more than 90% of tumor cell clusters were effectively preserved after separation. Finally, we successfully applied our device for the ternary separation of single tumor cells, tumor cell clusters, and WBCs from different malignant effusions collected from patients with metastatic cancer. Thus, our spiral-contraction-expansion device has potential as a sample pretreatment tool for the cytological diagnosis of malignant effusions.
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- 2024
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30. Gas desorption law of coal particles and calculation method of gas loss during fixed‐point closed sampling
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Zhihui Wen, Xinliang Wu, Jianping Wei, Yanping Wang, Jiangang Ren, and Ran Jia
- Subjects
accurate measurement ,calculation of gas loss ,closed sampling ,gas content ,Sun's formula ,Technology ,Science - Abstract
Abstract With the application of new technologies for coal mine gas control, it has been increasingly urgent to apply the fixed‐point closed sampling (FPCS) technology for accurate measurement of coal seam gas content. In this study, gas desorption during FPCS was analyzed. In addition, gas desorption experiments and COMSOL simulations were conducted on coal particles. Furthermore, the gas desorption law during FPCS was compared with that under atmospheric pressure. The results show that Sun's formula can effectively characterize the gas desorption law during FPCS, and the i value remains unchanged when the gas desorption curve is fitted with Sun's formula. On this basis, a specific method for calculating gas loss during FPCS by using Sun's formula was proposed. The research findings are expected to provide a theoretical basis for accurate measurement of coal seam gas content by means of FPCS.
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- 2024
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31. Online estimation of lithium battery SOC based on fractional order FOUKF‐FOMIUKF algorithm with multiple time scales
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Likun Xing, Hengqi Ren, Wenfei Luo, Zhenyun Zhang, and Yangwanhao Song
- Subjects
a theory of multi‐innovations discrimination ,fractional order models ,on‐line parameter recognition ,state of charge ,unscented Kalman filter algorithm ,Technology ,Science - Abstract
Abstract Aiming at the matter of poor precision in predicting the charge of lithium battery by applying conventional integer‐order models and offline parameter identification, this paper proposes a joint fractional‐order multi‐innovations unscented Kalman filter (FOUKF‐FOMIUKF) algorithm for predicting the cells' state of charge (SOC) online and uses the theory of singular‐value decomposition to tackle the issue of failure of the traceless transformation. Initially, the circuitry model of fractional order is built. The parameters of the model are recognized online by fractional‐order unscented Kalman filtering (FOUKF), and the obtained parameters are then transmitted to the method known as the fractional order multi‐innovations unscented Kalman filter (FOMIUKF) to calculate the SOC of the cell. The algorithm was validated under four working conditions such as FUDS (US Federal Urban Driving Distance), BJDST (Beijing Dynamic Stress Test), DST (Dynamic Stress Test), and US06 (Highway Driving Distance Test), respectively, and compared with the FOMIUKF, MIUKF, and FOUKF algorithms for offline identification. The conclusions demonstrate that the SOC estimated by the FOUKF‐FOMIUKF method is controlled within 0.5% of the mean absolute error under the four conditions and the root‐mean‐square error is controlled within 0.8%. It is not difficult to find that the FOUKF‐FOMIUKF algorithm estimates SOC with higher accuracy and robustness.
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- 2024
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32. The Roadmap of 2D Materials and Devices Toward Chips
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Anhan Liu, Xiaowei Zhang, Ziyu Liu, Yuning Li, Xueyang Peng, Xin Li, Yue Qin, Chen Hu, Yanqing Qiu, Han Jiang, Yang Wang, Yifan Li, Jun Tang, Jun Liu, Hao Guo, Tao Deng, Songang Peng, He Tian, and Tian-Ling Ren
- Subjects
Two-dimensional materials ,Roadmap ,Integrated circuits ,Post-Moore era ,Technology - Abstract
Highlights This review introduces the potential of 2D electronics for post-Moore era and discusses their current progress in digital circuits, analog circuits, heterogeneous integration, sensing circuits, artificial intelligence chips, and quantum chips in sequence. A comprehensive analysis of the current trends and challenges encountered in the development of 2D materials is summarized. An in-depth roadmap outlining the future development of 2D electronics is presented, and the most accessible and promising avenues for 2D electronics are suggested.
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- 2024
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33. Molecular Mechanisms of Intracellular Delivery of Nanoparticles Monitored by an Enzyme-Induced Proximity Labeling
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Junji Ren, Zibin Zhang, Shuo Geng, Yuxi Cheng, Huize Han, Zhipu Fan, Wenbing Dai, Hua Zhang, Xueqing Wang, Qiang Zhang, and Bing He
- Subjects
Enzyme-induced proximity labeling ,Intracellular delivery ,Nano-protein interaction ,Dynamic molecule profiling ,Macrophages ,Technology - Abstract
Highlights Novel enzyme-induced proximity labeling technology in nanoparticles (nano-EPL). Nano-EPL enables dynamic molecular mapping of the intracellular delivery of nanoparticles in macrophages. Nano-EPL enables the elucidation of a comprehensive phagosome-centered timeline during the vesicular transportation of nanoparticles, revealing distinct organelle engagement and its differential impact on drug delivery efficiency.
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- 2024
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34. Thioacetamide Additive Homogenizing Zn Deposition Revealed by In Situ Digital Holography for Advanced Zn Ion Batteries
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Kaixin Ren, Min Li, Qinghong Wang, Baohua Liu, Chuang Sun, Boyu Yuan, Chao Lai, Lifang Jiao, and Chao Wang
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Digital holographic microscopy ,In situ observation ,Electrode/electrolyte interface ,Zn dendrites ,Screening electrolyte additives ,Technology - Abstract
Highlights Digital holography can realize the in situ observation of electrode/electrolyte interface and provide dynamic evolution information of the liquid phase of electrode, which is both efficient and effective in investing the interficial electrochemical mechanism and screening electrolyte additives. Thioacetamide electrolyte additive effectively enhances the electrochemical performance of Zn anode by regulating the interficial ion flux to induce dendrite-free Zn deposition and constructing adsorption molecule layers to inhibit side reactions.
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- 2024
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35. Impacts of hot and cold nights on mental disorders: A three-stage nationwide hospital-based time-series study with 1.2 million patients in China
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Junwen Tao, Yongming Zhang, Qiyue Wu, Min Yang, Shilu Tong, Zhoupeng Ren, Zhiwei Xu, Hung Chak Ho, Mohammad Zahid Hossain, Yuanyong Xu, Xianyu Wei, Zhiwei Li, Hao Zheng, Hong Su, Wenyi Zhang, and Jian Cheng
- Subjects
Hot night ,Cold night ,Mental health ,Disease burden ,Technology ,Medicine - Abstract
Background: Climate change has shifted and will continue to alter the patterns of daytime and nighttime temperatures. However, it remains unclear whether hot days and nights, as well as cold days and nights, have varying impacts on mental disorders. Methods: Daily hospital-based data on 1.2 million outpatient visits for mental disorders were obtained from 15 Chinese cities (2011-2015). The index of hot day excess, hot night excess, cold day excess, and cold night excess were used to measure the intensity of hot/cold days and nights. Firstly, a distributed lag non-linear model was used to estimate the risk of mental disorders associated with hot/cold days and nights for each city. Secondly, city-specific estimates were pooled by multivariate meta-analysis to obtain national effect estimates. Thirdly, the attributable fraction of mental disorders was estimated for the nation, genders, age groups, heating methods, and air conditioning penetration rates. Results: Our findings revealed that both hot and cold nights were associated with a higher risk of mental disorders compared to hot and cold days. The attributable fraction of mental disorders was higher for cold (night: 25.74%; day: 19.65%) in contrast to heat (night: 16.91%; day: 7.24%). Males, the elderly, cities using central heating, and cities with low air conditioning penetration rates were vulnerable to cold nights. Conclusions: This nationwide study highlights the adverse effects and significant burden of hot and cold nights on mental disorders. It underscores the potential for mitigating these impacts through the adoption of air conditioning, particularly in southern cities across China.
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- 2024
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36. Research Progress on Tribological Properties of Polymer Composite Materials for Water-Lubricated Bearings
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TIAN Ying, CHE Qinglun, HE Ren, ZHANG Ga, ZHENG Shaomei
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water lubricated bearings ,polymer composites ,transfer film ,tribological mechanisms ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Technology - Abstract
Polymer composite materials have attracted considerable attention due to their excellent self-lubricating properties,high chemical stability and vibration damping and noise reduction characteristics.Water-lubricated bearings,which utilize water as the working medium,are characterized by their environmental friendliness,low maintenance costs and simplicity in structural design.They have been extensively applied in various domains including shipping,hydropower and the chemical industry.In this paper,the characteristics of polymer composite materials for water-lubricated bearings were initially summarized.The tribological properties and wear mechanisms of polymer composites under water lubrication conditions were then elucidated.Conventional methods for enhancing the tribological performance of polymer composites were introduced and further exploration were conducted on the intrinsic correlation between the internal structure of the materials,the microstructure of the friction interface and the macroscopic tribological characteristics of the materials.It was pointed out that promoting the in-situ growth of solid lubricating transfer films at the friction interface of water-lubricated polymer-metal pairs could compensate for the insufficiency of water film lubrication and significantly enhance the tribological performance of the pairings.An in-depth study of the micro-mechanisms of friction and wear in composite materials under water lubrication conditions is of significant importance for understanding the tribological mechanisms of water-lubricated pairings.
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- 2024
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37. Domestic Application Status of Downhole Corrosion Inspection and Monitoring Technique in Oil and Gas Wells
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WU Yusheng, FENG Qiang, REN Jian, WANG Jianming, HE Sha, ZHAO Yanfeng, DENG Weilin, GE Kaiqi, YANG Yunhao
- Subjects
downhole ,corrosion ,inspection technique ,monitoring technique ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Technology - Abstract
In order to find corrosion and other defects of downhole tubing as early as possible in oil and gas production,and to ensure safe and efficient production of oil and gas,the article gave an overview of existing downhole corrosion inspection techniques and monitoring techniques for oil and gas wells both domestically and internationally.The application of the above techniques in domestic oil and gas fields were analyzed,and the prospects for the development of related techniques were putted forward.Furthermore,it was considered that improving the reliability and adaptability of the technology and equipment and achieving online monitoring and real-time monitoring were very important directions of researches.
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- 2024
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38. Influence of Repetitive Impulse Waveforms on Surface Discharge Characteristics and Insulation Life for Polyimide Film
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Zhiyun Han, Qingmin Li, Yujin Guo, Tao Liu, Guojing Dong, and Hanwen Ren
- Subjects
Insulation life ,polyimide film ,power electronic transformer ,repetitive impulse ,surface discharge characteristics ,Technology ,Physics ,QC1-999 - Abstract
Accelerated insulation aging problems under high frequency repetitive impulses in power electronic transformers are drawing more and more attention in modern power systems. Partial discharge (PD) characteristics including discharge inception voltage, phase distribution and statistical characteristics on polyimide (PI) surface under different impulse waveforms and the insulation life of PI films are studied in this paper. We carry out experiments based on PD and insulation lifetime test systems, using five different types of repetitive impulses, including three bipolar waves and two unipolar waves. The experimental results show that there is little variation in discharge inception voltage under different waveforms, but great variation in phase distribution and statistical characteristics of PD. In addition, insulation life is approximately the same under different waveforms with the same polarity, and the aging rate under bipolar waveforms is larger than that under unipolar waveforms. We explain the differences between the bipolar and unipolar waveforms on insulation life, which can be concluded that the surface charge under unipolar waveform accumulates more significnatly compared with bipolar waveform and decreases the electric filed strength in discharging the air gap and inhibits surface discharge from occurring.
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- 2024
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39. Short-term Fault Prediction Method for Bearing Based on SA-TCN
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Siyuan WANG, Junghui CHEN, Kai GU, Mifeng REN, and Gaowei YAN
- Subjects
short-term failure prediction ,temporal convolutional network ,bearing ,attention mechanism ,Chemical engineering ,TP155-156 ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Technology - Abstract
Purposes Bearing is one of the core components in the manufacturing industry. Its health status determines the safety of the host. Short-term failure prediction can effectively ensure the smooth progress of the industrial production process. Methods In order to solve the end-to-end problem, a temporal convolutional network (TCN) based short-term fault prediction strategy was proposed. The network could directly output the types of failure that would eventually occur in the bearing and the degradation stage that would be in the next moment through the data monitored at the current moment. In addition, soft threshold with attention mechanism is proposed to solve the problem of background noise in the working environment of bearings or noise interference in the process of data acquisition. During the short-term fault prediction process, the attention mechanism adaptively generates a soft threshold according to the prediction target of the TCN network, and the soft threshold acts on the spatiotemporal features extracted by the TCN to achieve the purpose of reducing noise impact. Findings The experimental results show that the proposed algorithm has high accuracy, which verifies the effectiveness and high practical engineering application value of the proposed algorithm.
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- 2024
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40. Understanding Discrepancy of Power System Dynamic Security Assessment with Unknown Faults: A Reliable Transfer Learning-based Method
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Chao Ren, Han Yu, Yan Xu, and Zhao Yang Dong
- Subjects
Adversarial training ,dynamic security assessment ,maximum classifier discrepancy ,missing data ,transfer learning ,Technology ,Physics ,QC1-999 - Abstract
This letter proposes a reliable transfer learning (RTL) method for pre-fault dynamic security assessment (DSA) in power systems to improve DSA performance in the presence of potentially related unknown faults. It takes individual discrep-ancies into consideration and can handle unknown faults with incomplete data. Extensive experiment results demonstrate high DSA accuracy and computational efficiency of the proposed RTL method. Theoretical analysis shows RTL can guarantee system performance.
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- 2024
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41. 3D-Printed Carbon-Based Conformal Electromagnetic Interference Shielding Module for Integrated Electronics
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Shaohong Shi, Yuheng Jiang, Hao Ren, Siwen Deng, Jianping Sun, Fangchao Cheng, Jingjing Jing, and Yinghong Chen
- Subjects
3D printing ,Carbon-based nanoparticles ,Conformal electromagnetic interference shielding ,Integrated electronics ,Technology - Abstract
Highlights 3D printable functional inks incorporated with graphene and carbon nanotube nanoparticles were well-formulated by manipulating their rheological performance The frame with ultralight structure (0.076 g cm−3) and high-efficiency electromagnetic interference shielding (61.4 dB) was assembled 3D-printed c-SE module was in situ integrated onto the electronics, affording multiple functions of electromagnetic compatibility and thermal dissipation.
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- 2024
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42. Pore structure of tight sandstones with differing permeability: The He 8 Member of the Middle Permian Lower Shihezi Formation, Gaoqiao area, Ordos Basin
- Author
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Dayou Chen, Yushuang Zhu, Wei Wang, Liling Zhang, Jianyun Tang, Jiangli Ren, and Yizhe Wang
- Subjects
different permeability ,He 8 Member ,nitrogen adsorption ,Ordos Basin ,pore structure ,tight sandstone ,Technology ,Science - Abstract
Abstract Tight sandstone has strong pore heterogeneity and complex pore structure, and the pore structure of tight sandstone varies with different permeability. To study the differences in the pore structure of tight sandstone with different permeability, this study investigated the tight sandstone of the He 8 Member in the Gaoqiao area of the Ordos Basin. Factors influencing pore formation are analyzed through experiments utilizing methods, such as distinguishing casting thin sections, scanning electron microscopy, high‐pressure mercury intrusion, and low‐temperature nitrogen adsorption. The results indicate that in this area, the pores of the tight sandstone are primarily dissolution and intercrystalline pores, with occasional intergranular pores and microcracks. Type Ⅱ samples (permeability > 0.2 × 10−3 μm2) are primarily composed of dissolution and intercrystalline pores, with a few visible intergranular and microcracks. In contrast, Type Ⅰ samples (permeability
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- 2024
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43. The effect of minor addition of Mn in AA7075 Al–Zn–Mg–Cu aluminum alloys on microstructural evolution and mechanical properties in warm forming and paint baking processes
- Author
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Cheng-Ling Tai, Yo-Ming Pua, Tsai-Fu Chung, Yo-Lun Yang, Hsueh-Ren Chen, Chih-Yuan Chen, Shing-Hoa Wang, Chung-Yi Yu, and Jer-Ren Yang
- Subjects
AA7075 aluminum alloys ,Warm forming ,Paint baking ,Mn addition ,Dispersoid ,High resolution transmission electron microscopy ,Technology - Abstract
The microstructures and mechanical properties in the peak ageing condition, warm forming process, and paint baking process of two Al–Zn–Mg–Cu aluminum alloys, which possessed the same base compositions but different levels of Mn (0 and 0.24 wt%), have been investigated. The results show that Mn addition can hardly refine the grain size (around 20 μm) in AA7075 aluminum alloy in warm forming and paint baking processes. Mn-free and Mn-containing alloys subjected to all three processes possess nano-precipitates of nearly the same size, indicating that Mn addition does not influence the nano-precipitate evolution in the aluminum matrix. Energy-dispersive X-ray spectroscopy (EDS) mapping results of dispersoids show that dispersoids in Mn-bearing specimens are enriched in Mn and depleted in Zn and Mg. The Zn and Mg expelled from dispersoids in Mn-containing specimens into the aluminum matrix presumably formed Zn- and Mg-rich zones around the dispersoids, which improved the precipitate transformation reation from GPII to η′ phase at the boundaries between aluminum matrix and dispersoids. Although the solid solution strengthening effect triggered by Mn addition might be less effective because of the formation of dispersoids, the slight enhancement of ultimate tensile strength (UTS) in Mn-containing specimens rather than in Mn-free specimens in all states can be attributed to the formation of nano-precipitates around the dispersoids.
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- 2023
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44. Synthesis and Lithium Storage Properties of One-dimensional Rod-shaped FeMo2S4
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Hongquan WANG, Jing REN, Jianqiang HAN, Ruipeng REN, and Yongkang LYU
- Subjects
lithium-ion batteries ,anode ,femo2s4 ,one-dimensional rod structure ,Chemical engineering ,TP155-156 ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Technology - Abstract
Purposes The rational design and regulation of the microstructure of electrode materials are the bases for significantly enhancing their electrochemical performance. Methods In this study, FeMo2S4 with a one-dimensional rod-like structure was synthesized by a solvent heat-calcination method and used as an anode material for lithium-ion batteries. Findings Compared with the irregular structured bulk electrode, the one-dimensional rod structure of FeMo2S4 reduces the ion/electron transport distance and improves the reaction kinetics. And the higher specific surface area provides abundant electrochemical active sites and increases the lithium storage capacity. The results show that the FeMo2S4 electrode has a high specific capacity (the initial discharge specific capacity and charge specific capacity are 1 201 and 976.2 mAh/g, respectively, at a current density of 0.5 A/g), good rate and cycling performance. Conclusions This study can provide guidance for the structural design and regulation of subsequent transition metal sulfide anode materials.
- Published
- 2023
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45. An overview of application-oriented multifunctional large-scale stationary battery and hydrogen hybrid energy storage system
- Author
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Yuchen Yang, Zhen Wu, Jing Yao, Tianlei Guo, Fusheng Yang, Zaoxiao Zhang, Jianwei Ren, Liangliang Jiang, and Bo Li
- Subjects
Hybrid energy storage system ,Battery ,Hydrogen ,Stationary ,Large-scale ,Multifunctional ,Technology ,Science (General) ,Q1-390 - Abstract
The imperative to address traditional energy crises and environmental concerns has accelerated the need for energy structure transformation. However, the variable nature of renewable energy poses challenges in meeting complex practical energy requirements. To address this issue, the construction of a multifunctional large-scale stationary energy storage system is considered an effective solution. This paper critically examines the battery and hydrogen hybrid energy storage systems. Both technologies face limitations hindering them from fully meeting future energy storage needs, such as large storage capacity in limited space, frequent storage with rapid response, and continuous storage without loss. Batteries, with their rapid response (90 %), excel in frequent short-duration energy storage. However, limitations such as a self-discharge rate (>1 %) and capacity loss (∼20 %) restrict their use for long-duration energy storage. Hydrogen, as a potential energy carrier, is suitable for large-scale, long-duration energy storage due to its high energy density, steady state, and low loss. Nevertheless, it is less efficient for frequent energy storage due to its low storage efficiency (∼50 %). Ongoing research suggests that a battery and hydrogen hybrid energy storage system could combine the strengths of both technologies to meet the growing demand for large-scale, long-duration energy storage. To assess their applied potentials, this paper provides a detailed analysis of the research status of both energy storage technologies using proposed key performance indices. Additionally, application-oriented future directions and challenges of the battery and hydrogen hybrid energy storage system are outlined from multiple perspectives, offering guidance for the development of advanced energy storage systems.
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- 2024
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46. Effects of normalizing and tempering temperature on the bainite microstructure and properties of low alloy fire-resistant steel bars
- Author
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Zheng Zhichao, Ren Jie, Zhang Li, Guan Lanfang, Liu Chengzhi, Liu Yanlian, Cheng Shengwei, Su Zexing, and Yang Fei
- Subjects
fire-resistant steel bars ,normalizing ,tempering ,bainite strengthening ,precipitation strengthening ,Technology ,Chemical technology ,TP1-1185 ,Chemicals: Manufacture, use, etc. ,TP200-248 - Abstract
Different combinations of normalizing and tempering were carried out to optimize the microstructure and enhance the high-temperature mechanical properties of HRB400FR fire-resistant steel bars. The results showed that with the increasing of the tempering temperature from 400 to 600°C, the steel bar’s hardness decreases linearly, mainly due to the formation of quasi-polygon ferrite and granular bainite. Besides, the reduced width and the dissolution of the lath bainite also undermine the performance of the tempered steel bars. The highest Vickers hardness of 380 HV is achieved when the steel is normalized at 950°C and then tempered at 400°C, mainly due to precipitation strengthening and bainite strengthening. The hardness of the test steel tempered at 600°C gives the lowest value, only 230 HV since the least amount of bainite is obtained. When the tempering temperature reaches 650°C, the hardness rises to 260 HV due to the formation of the lath bainite. The emergence of needle bainite generally reduces the matrix grain size, and the appearance of lath martensite refines the precipitated carbides.
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- 2024
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47. Application of an active learning method for cumulative fatigue damage assessment of floating wind turbine mooring lines
- Author
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Chao Ren, Yihan Xing, and Karan Sandipkumar Patel
- Subjects
Cumulative fatigue damage ,Mooring lines ,Floating wind turbine ,Active learning ,Gaussian process regression ,AK-DA approach ,Technology - Abstract
Long-term cumulative fatigue damage of mooring lines is crucial for the design of floating wind turbine structures (FWTs). Although many efforts are carried out for the offshore floating platforms, there still needs to be an efficient approach for assessing the long-term fatigue damage of the floating wind turbine mooring lines due to the complex loading in FWTs. An active learning approach named AK-DA (Adaptive Kriging Damage Assessment) was recently proposed for the cumulative fatigue damage assessment of wind turbine structures. However, in the original work, the AK-DA approach was only tested on fatigue damage assessment of a 5MW wind turbine tower with monopile support structures. It is unclear whether it is applicable to other parts of the wind turbine system, especially considering the complex loading of FWTs. Therefore, in this work, the AK-DA approach is used to assess the cumulative fatigue damage of mooring lines. The Gaussian process regression (Kriging) model is used to predict the fatigue damage of the mooring line under different wind-wave cases. The cumulative fatigue damage of the mooring lines in the IEA 15MW semi-submersible wind turbines is assessed with the AK-DA approach. The numerical simulation results show that the AK-DA approach can efficiently and accurately estimate the cumulative fatigue damage of the mooring lines. Compared to the traditional simulation approach, the AK-DA approach can increase efficiency by more than 45 times, and the absolute error is less than 1%. This active learning approach could serve as a helpful tool for offshore mooring system designers, facilitating the cumulative fatigue damage assessment during the design process.
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- 2024
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48. Updates on Hydrogen Value Chain: A Strategic Roadmap
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Julio Garcia‐Navarro, Mark A. Isaacs, Marco Favaro, Dan Ren, Wee‐Jun Ong, Michael Grätzel, and Pablo Jiménez‐Calvo
- Subjects
consumption ,hydrogen ,production ,storage ,transport ,value chain ,Technology ,Environmental sciences ,GE1-350 - Abstract
Abstract A strategic roadmap for noncarbonized fuels is a global priority, and the reduction of carbon dioxide emissions is a key focus of the Paris Agreement to mitigate the effects of rising temperatures. In this context, hydrogen is a promising noncarbonized fuel, but the pace of its implementation will depend on the engineering advancements made at each step of its value chain. To accelerate its adoption, various applications of hydrogen across industries, transport, power, and building sectors have been identified, where it can be used as a feedstock, fuel, or energy carrier and storage. However, widespread usage of hydrogen will depend on its political, industrial, and social acceptance. It is essential to carefully assess the hydrogen value chain and compare it with existing solar technologies. The major challenge to widespread adoption of hydrogen is its cost as outlined in the roadmap for hydrogen. It needs to be produced at the levelized cost of hydrogen of less than $2 kg−1 to be competitive with the established process of steam methane reforming. Therefore, this review provides a comprehensive analysis of each step of the hydrogen value chain, outlining both the current challenges and recent advances.
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- 2024
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49. Editorial: Advanced materials and technique for structural monitoring, analysis, and control
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Chun-Xu Qu, Liang Ren, Yunlai Zhou, Qian Feng, and Sadegh Shams
- Subjects
structural monitoring ,structural analysis ,structural control ,engineering ,advanced materials ,Technology - Published
- 2024
- Full Text
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50. Study of low-toxicity copper pyrithione as a multifunctional additive for lithium grease
- Author
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Ren Jia, Haopeng Cai, Gaiqing Zhao, Zhuang Xu, and Xiaobo Wang
- Subjects
Antimicrobial ,Extreme pressure ,Friction reduction and antiwear ,Multifunctional additive ,Technology - Abstract
The feasibility of CuP as a multifunctional additive in lithium grease was evaluated for the first time. The experimental results indicated that the CuP significantly enhanced the friction reduction, antiwear properties, extreme pressure capabilities, and antimicrobial characteristics of lithium greases. The SRV test results suggested that the optimal tribological properties were obtained by adding 3 wt% of CuP to lithium greases, resulting in a decrease of the friction coefficient and wear volume by 28.25% and 34.98%, respectively. The four-ball results confirmed that the extreme pressure performance of the lithium grease with 3 wt% CuP was enhanced by a factor of 3.17. The bacterial inhibition rate of lithium grease with 3 wt% CuP was higher than 99.98%. The lubrication mechanism and antimicrobial mechanism was explained.
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- 2024
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