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We report a smart ion-exchange strategy to anchor molybdenum oxide particles on charge-modulated conjugated triazine frameworks (Mo/CTF-I) for electrochemically fixing nitrogen.

An economically feasible green route for the synthesis of poly(tetramethylene ether glycol) (PTMEG) and methane from furfural (FA).

A highly effective and stable Pt/HAP catalyst was developed for the hydrogen-free deoxygenation of lipids to alkanes via specific stabilization and synergistic effect, which achieved ca. 90% yield at 320 °C at a high rate of 300 g∙gPt−1∙h−1 with 50 wt% reactant concentration in dodecane. Such catalytic system was adapted to various triglyceride feedstock and even unprocessed waste oil, showing superior activities than other reported Pt catalysts. The Pt precursor was ion-exchanged with the OH surface groups of HAP, as confirmed by characterizations of CO2-TPD, NH3-TPD and IR, forming uniform and small Pt nanoparticles with an average size of 0.7 nm after reduction. Even after eight recycling runs, the particle sizes were slightly turned into 1.6 nm with high reactivity and stability. In situ IR spectra showed that carboxylic acid was physically adsorbed on Pt/SiO 2 and adsorbed as a bidentate on Pt/Al2O3, while adsorbed as a chelation on Pt/HAP-IE in comparison. Upon adsorption, protons of the carboxyl group were dissociated by phosphate, and the generated carboxylate anions were adsorbed on Ca2+ to form a chelated structure. Such adsorption mode activated carboxylates, which trended to be fast cleaved by the adjacent Pt nanoparticles anchored by OH groups to catalyze the target decarboxylation reaction, achieving the multi-functional synergistic catalysis. This Pt/HAP-IE catalyst can be applied to the hydrogen-free decarboxylation reactions, especially for the deoxygenation of compounds containing unsaturated C C, C O, C O, and O H bonds that are sensitive to hydrogen.

Profile shift is a powerful tool for increasing the gear tooth thickness and enhancing bending fatigue strength. However, it is one-sided to only improve the bending fatigue life of positive profile-shifted spur gear by strengthening the gear tooth body. Furthermore, the current research has not revealed the effect of profile shift on the dynamic load of the gear system with tooth root crack. Therefore, this paper establishes a novel analytical model. Based on the revised tooth shape, the model considers bending, shear, axial compressive, contact Hertzian, and fillet foundation potential energies. The results show that the negative profile shift is more sensitive to the root mean square value (RMS) of time-varying meshing stiffness (TVMS) than the positive. The negative profile-shifted gear provides high TVMS due to the high contact ratio under the health state. In comparison, it loses more TVMS with the crack propagation. Moreover, the positive profile-shifted gear has a lower effective meshing force and vibration intensity value in crack propagation than the negative. Overall, the positive profile shift can increase gear tooth life because it thickens the gear tooth and simultaneously decreases the dynamic load.

The microstructure evolution of Al-Zn-Mg-Cu alloy with erbium was studied by optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) during homogenization process. The results showed that there were serious component segregation in the as-cast structure of the alloy, mainly composed of T(AlZnMgCu) , S(Al2CuMg) and a small amount of Al8Cu4Er and Al7Cu2Fe. The overheating temperature of the alloy was 482.5 °C. After homogenized at 470 °C for 24 h, the dissolution of T(AlZnMgCu) phase and S(Al2CuMg) phase reached to a balance, but the residual Al8Cu4Er phase could not be dissolved completely. Compared with single-stage homogenization, Al3(Er,Zr) dispersion phase with smaller grain size and more uniform distribution can be obtained after two stage homogenization process of 400 °C for 8 h followed by 470 °C for 24 h. By comparing the residue of non-equilibrium eutectic phase, two-stage homogenization is the best.

A new type of near α high temperature titanium alloy of Ti-Al-Sn-Zr-Mo-Si-Er was studied. The samples with different primary α phase content were prepared by solid solution at 950 °C/1 h—1010 °C/1 h. The multi-step hot compression experiments were carried out by Gleeble-3500 in a sequence of upper region of α + β phase, then followed by lower region of α + β phase. The effects of primary α phase content and deformation temperature on the microstructure of the alloy were studied by means of true stress-strain curve and optical microscope. The results show that the content of primary α phase gradually decreases from 45.4% at 950°C to 0% at 1010°C. As the deformation temperature decreases from 940°C to 900°C, the content of α phase increases gradually from 65% to 94%, which is changed from dynamic recrystallization to deformed structure elongated along RD direction. It is found that the arrangement of α phase along RD direction is the longest at 920°C. With the increase of the deformation temperature in the multi-step high temperature region from 970°C to 990°C, the width of deformed α phase decreases from 3.64 μm at 970°C to 2.71 μm at 990°C. The optimized microstructure is composed of 20% primary α phase arranged along RD direction. This process has a certain potential in the process of hot deformation of the alloy. Key words: high temperature titanium alloy, primary α phase, multi-step hot deformation

The effects of the heat treatment process parameters on the microstructure and mechanical properties of a selective laser melted (SLMed) AlSi10Mg alloy were systematically investigated. The SLMed AlSi10Mg alloy was treated with T1 (180°C× 4h + air cooling) process, which had the microstructure of fine α-Al grains, fine Si phase, and nano-sized precipitations. The microhardness significantly increased to 150 HV, which is even higher than as-SLMed one (126 HV). The microhardness of SLMed AlSi10Mg alloy treated with T4 (540°C × 2h + water cooling) heat-treatment process significantly decreased to 62 HV due to the growth of α-Al grains, Si phase and the formation of β-AlFeSi phase. However, the microhardness and ultimate tensile strength of AlSi10Mg alloy treated with T6 (540°C × 2 h water cool + 180°C × 4 h air cool) process decreased to 91 HV, although the strengthening precipitation of Mg2Si phase formed. It indicates that the Mg2Si phase cannot compensate for the adverse effect of grain growth. It may provide the best potential heat treatment method for fabricating the high strength SLMed AlSi10Mg alloy.

An efficient formaldehyde (HCHO) gas sensor system based on nickel-doped tin oxide (Ni-doped SnO2) nanoparticle sensor and back-end circuit has been developed. Ni-doped SnO2 nanoparticles are prepared by a simple one-step hydrothermal method. To complete the function of detecting HCHO gas in real time, a back-end circuit suitable for resistance measurement of nanoparticle sensors and an organic light emitting diode screen which can display the output of gas concentration data are integrated as a portable device. Compared with the traditional HCHO detection device, this designed system exhibits better stability, excellent selectivity, and high response. Its detection limit is as low as 90 ppb. The gas response to 50 ppm HCHO is 67.63. Further for the quantitative evaluation, we refer to and modify the existing HCHO diffusion model, then carry out a practical test on the HCHO diffusion at the same time. The comparison between the theoretical fitting curve and the actual test curve matched well enough to reflect the potential of this system for the practical HCHO evaluation.

Commercially pure Ti and Ti-based alloys produced by laser powder bed fusion (L-PBF) processes have been extensively studied. However, there are few special Ti-based alloys that are applicable to L-PBF. This work aims to study the effect of the laser power and scanning speed on the density and surface morphology of novel Ti-6Zr-5Fe alloys. The obtained results indicate that the Ti-6Zr-5Fe alloy is suitable for powder preparation. With increasing laser power and a decrease in the scanning speed, the density of the L-PBF Ti-6Zr-5Fe alloy increased, while less un-melted powder particles and a smoother surface were obtained. The present results may provide a guideline for designing special L-PBF alloys.

Metal phthalocyanine (MPc) has a great saturation response value, but its low conductivity and slow response speed limit its practical application. A novel hybrid material composed of graphene quantum dots (GQDs) and metal phthalocyanine derivatives has been obtained. GQDs can be anchored onto the surface of MPc nanofibers through π–π stacking. The response to NO2 can be significantly enhanced under certain component proportion matching, which is much better than their respective response to NO2. The introduction of GQDs greatly increases the conductivity of phthalocyanine fibers, leading to a faster response of the hybrid material. In addition, the reproducibility, selectivity and stability of the hybrid materials are excellent, and the minimum response concentration can reach 50 ppb. Ultra-low-power laser irradiation was used to solve the problem of slow recovery of metal phthalocyanine. Overall, we present the advantages of combining MPc nanofibers with GQDs and pave a new avenue for the application of MPc–GQD hybrids in the gas sensing field.

In this study, a polysilane-modified graphene oxide (GO) and carbon nanotube (CNT) nanocomposite (GO/CNTs-Si) was prepared as a thermal conductive nanofiller to enhance the thermal and mechanical properties of silicone rubber composites. By γ-ray-radiation 3-methacryloxypropyltrimethoxy silane (MPTMS) was polymerized on the surface of GO and CNTs to improve the interfacial interaction between the GO/CNTs-Si and SR matrix. FTIR characterization results demonstrated that polysilane modified the GO/CNTs successfully. The pristine GO/CNTs and resultant GO/CNTs-Si were individually incorporated into α,ω-dihydroxypolydimethylsiloxane to vulcanize SR composites. Compared with SR-GO/CNTs, SR-GO/CNT-Si exhibited better mechanical and thermal performance. Moreover, the time-dependent complex modulus of SR-GO/CNTs-Si was much higher than that of SR-GO/CNTs, which indicates longer service time and more stable performance. In terms of electronic packaging, SR-GO/CNTs exhibited better performance than the 1180B counterpart. The low value of warpage of chip packaged by SR-GO/CNTs implied that SR-GO/CNTs-Si could have potential application as the thermal interface electronic packaging material.

Toluene biodegradation from synthetic waste gas by aerobic denitrification using nitrate as an electron acceptor in a biotrickling filter (BTF) was investigated. Toluene removal efficiency achieved...

With the transformation from traditional manufacturing to intelligent manufacturing, customer-oriented personalized customization has gradually become the main mode of production. Interactive algorithms determine the pros and cons of the solution via customers which can make customers better participants in the customization process. However, if the population size is expanded and the number of evolutionary iterations is too high, frequent interactions are likely to cause customer fatigue. This paper proposes an adaptive interactive artificial immune algorithm based on improved hierarchical clustering. This algorithm uses the improved hierarchical clustering algorithm to optimize generation of the initial antibodies and applies the affinity calculation method based on customer intention, adaptive crossover and mutation operators, and a multisolution reservation method based on hybrid selection strategy to the artificial immune algorithm. Via empirical research on the customized operational data of wheel hubs, the proposed method effectively solves the problem of customer fatigue, significantly improves the convergence speed of the algorithm and reduces the time cost.

Purpose The individualized prediction of postoperative symptom severity is essential for selecting interventions after mandibular third molar (M3M) removal. The purpose of the present study was to develop and validate a nomogram for personal prediction of postoperative symptom severity. Materials and Methods A prospective cohort study was performed in the Stomatology Hospital of Tianjin Medical University. The sample was divided into training and testing data sets by time. The demographic, anatomic, radiographic, and operative variables were recorded. The self-reported postoperative symptom severity was recorded and defined as the primary outcome variable. Stepwise forward algorithms were applied to informative predictors based on Akaike's information criterion. Multivariable logistic regression analysis was used to develop the nomogram. An independent testing data set was used to validate the nomogram. Receiver operating characteristic curves and the Hosmer-Lemeshow test were used to assess model performance. P Results The sample included 321 subjects who had undergone M3M removal. An independent validation data set included 103 consecutive patients. The median operation time was 15.0 minutes (interquartile range, 8.3 to 21.6 minutes) in the training data set (n = 218). Patients with serious postoperative symptoms accounted for 48.6 and 47.6% of the training and testing data sets, respectively. Gender, age, smoking status, operation time, Pell-Gregory ramus classification, and preoperative symptoms were identified as predictors and assembled into the nomogram. The area under curve demonstrated adequate discrimination in the validation data set (0.69; 95% confidence interval, 0.59 to 0.80). The nomogram was well calibrated, with a Hosmer-Lemeshow χ2 statistic of 6.33 (P = .78) in the testing data set. The confusion matrix was also summarized, and the accuracy was 63.3 and 65.1% in the training and testing data set, respectively. Conclusions The present study has proposed an effective nomogram with potential application in facilitating the individualized prediction of postoperative symptom severity after M3M removal.

The effect of the primary α content and precipitate on the creep resistance of a high-temperature titanium alloy with a small amount of Hf addition were studied. The microstructures with different primary α contents were prepared by the heat treatment of 920~1010 °C /1 h+700 °C/5 h, and the creep test (600 °C/150 MPa/100 h) was carried out. The interaction between the precipitation phase and the dislocation configuration was analyzed. The results showed that with the increase of solution temperature, the volume fraction of primary α phase decreased from 44.9% at 920 °C to 0% at 1010 °C, and the steady state creep rate of the alloy decreased from 60.60×10-4%/h to 3.72×10-4%/h, indicating that the creep property was significantly improved with the decrease of solution temperature. The basket structure with optimal creep resistance was obtained under the heat treatment of 1010 °C/1 h+700 °C/5 h. It is believed that during the high temperature creep test, the precipitated α2 phase and the hafnium-containing silicide hinder the dislocation motion in α crystal and the phase boundary, thereby improving the creep resistance of the alloy.

In this paper, an Al-Zn-Mg-Cu alloy with a small amount of Er and Zr added was used as the research object. The homogenization annealing was carried out, and the 7N01 aluminum alloy was used at 300 °C, 350 °C, 400 °C, 450 °C and 0.1 s-1, 1 s-1, 10 s-1 deformation conditions by Gleeble-3500 thermal simulator. Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM) were used for microstructure analysis. The results show that the stress-strain curve of with Er 7N01 aluminum alloy can be divided into micro-strain stage, uniform deformation stage and steady-state flow stage during the thermal compression process. The flow stress of 7N01 aluminum alloy achieved peaks at the initial stage of strain, and then increased with the increase of strain rate and the decrease of deformation temperature. With the increase of deformation temperature and the decrease of deformation rate, the recrystallization process was significantly increased.

Chemical warfare agents, particularly nerve agents such as sarin, are exceptionally harmful and incredibly perilous to people. Thus, the sensitive detection of these gases is indispensable for reducing the risk of chemical weapons. Herein, we fabricated a room-temperature chemiresistive gas sensor based on two-dimensional few-layer tungsten diselenide (WSe2) nanosheets, which were prepared through a facile liquid-phase exfoliation method. The WSe2-based sensor has demonstrated sensitive and selective detection of dimethyl methylphosphonate (DMMP), which is a well-known simulant of the nerve agent sarin. The sensor based on WSe2 nanosheets revealed a high response reaching 8.91% to 10 ppm DMMP with a fast response time of 100 s. Furthermore, the sensor displayed reliable stability, excellent selectivity, and a low theoretical limit of detection of about 122 ppb. The enhanced sensing performance of WSe2 nanosheets can be ascribed to the increase of the specific surface area, which provides more active adsorption sites for DMMP molecules, thereby facilitating the charge transfer process between DMMP molecules and WSe2 nanosheets. Overall, our results indicate that two-dimensional transition metal dichalcogenide materials have the potential for the design and fabrication of high-performance nerve agent sensing devices.

The recalcitrance of lignin with non-hydrolyzable C–O–C bonds, as well as the tendency for its phenolic fragments to polymerize into more recalcitrant polymers, leads to low-efficiency lignin deconstruction processes, such as low lignin concentrations during treatment. Herein, we developed a tandem catalytic approach for the conversion of highly concentrated lignin to stable cyclic alkanes by introducing Pt/HAP into a Ni/ASA catalyst in dodecane media. The incorporated Pt/HAP changes the simultaneous hydrogenation and hydrogenolysis of lignin on Ni/ASA into tandem reactions on a physically mixed Pt/HAP and Ni/ASA catalyst, involving the initial selective lignin depolymerization over Pt/HAP and the following hydrodeoxygenation of phenols over Ni/ASA, as evidenced by kinetic studies. In this tandem approach, the preferred initial lignin depolymerization, instead of lignin hydrogenation, originates from the strong adsorption and high C–O cleavage selectivity of lignin on the introduced Pt/HAP, as confirmed by UV-Vis, gel permeation chromatography (GPC), 2D-heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC NMR), and catalytic tests. The rates of lignin depolymerization and the hydrodeoxygenation of depolymerized phenols are matched when the mass ratio of Pt/HAP and Ni/ASA is set at 1 : 1, allowing this approach to proceed with the highest lignin concentrations (150 g L−1) so far reported, with conversion to cyclic alkanes with 42 wt% yield without coke formation in dodecane at 300 °C in the presence of 6 MPa H2. Promisingly, the developed approach may lay a solid foundation for future industrial applications relating to lignin valorization.

A denitrifying/nitrifying membrane biofilm reactor for simultaneous removal of Hg0 and NO was investigated. Hg0 and NO removal efficiency attained 94.5% and 86%, respectively. The mercury-oxidizing microbial community was significantly shaped by nitrification/denitrification after the supply of gaseous Hg0and NO continuously. Dominant genera Rhodanobacter and Nitrosomonas participated in Hg0 oxidation, nitrification and denitrification simultaneously. Hg0 oxidizing bacteria (Gallionella, Rhodanobacter, Ottowia, Nitrosomonas and etc.), nitrifying bacteria (Nitrosomonas, Rhodanobacter, Diaphorobacte and etc.) and denitrifying bacteria (Nitrosomonas, Rhodanobacter, Castellaniella and etc.) co-existed in the MBfR, as shown by metagenomic sequencing. X-ray photoelectron spectroscopy (XPS) and high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) confirmed the formation of a mercuric species (Hg2+) from mercury bio-oxidation. Mechanism of mercury oxidation can be described as the bacterial oxidation of Hg0 in which Hg0 serves as electron donor, NO serves as electron donor in nitrification and electron acceptor in denitrification, oxygen serves as electron acceptor.

In this contribution, we report a facile and green process for the quantitative transformation of natural oils, fatty esters, and fatty acids to fatty alcohols over N-modified carbon (N–C) supported RuSn catalysts in water at low temperatures (140–180 °C). The synthesis of the N–C support was carried out by using a one-pot process with melamine, glucose, and ZnCl2 as reactants. The presence of Sn nanoparticles, and pyridinic and pyrrolic nitrogen in the modified N–C support favoured the good dispersion of Ru nanoparticles, improved the hydrophilic properties of the catalyst for staying in the water layer, and facilitated the adsorption of the carbonyl groups. After strongly interacting with the carbonyl group of fatty acids over Sn nanoparticles and N-groups, Ru nanoparticles catalysed the further acid hydrogenation to the intermediate aldehyde, and subsequently to the target fatty alcohol at a fast rate. This provides a useful and simple method for synthesizing highly hydrothermal-stable metal supported carbon catalysts, which can facilely and selectively hydrogenate the aqueous biomass to value-added chemicals.

The served harsh environment of advanced aircraft engine puts forward higher requirements for high temperature titanium alloy performance. The optimized heat treatment technology provides effective theoretical basis for improving the microstructure and properties of high temperature titanium alloys. In this paper, we study the influence of different heat treatment systems on microstructure and mechanical properties of high temperature alloy with equiaxed structure, in order to obtain the corresponding relationship between the process and the microstructure performance of the alloy and the optimal heat treatment process. Analysis the effect of solution treatment on the primary α phase quantitatively by optical microscope and Image-Pro-Plus 6.0 software based on the forged high temperature titanium alloy in α+β phase region. Observe the precipitation of α2 phase and silicide by TEM, optimize the aging process according to hardness test. The results show that the content of primary a phase decrease from 63.3% at 920°C to 15.3% at 990°C with the increase of solution temperature. When the temperature rises to 980~990°C, the structure changes from equiaxed structure to α+β duplex microstructure. And change into lamellar structure when the solution temperature raise to 1010°C. The secondary α phase precipitates more fully when the aging temperature increases. And with increasing aging time, the trend of α2 phase growth become more significantly. The optimum heat treatment system obtained in this experimental is 990°C/1h/AC+700°C/5h/AC, and the α phase is about 15.3%. Hence, the excellent microstructure and properties match has been obtained.

Luminescence, a physical phenomenon that producing cool light in vivo, has been found in bacteria, fungi and animals but not yet in terrestrial higher plants. Through genetic engineering, it is feasible to introduce luminescence systems into living plant cells as biomarkers. Recently, some plants transformed with luminescent systems can glimmer in darkness, which can be observed by our naked eyes and provides a novel lighting resource. In this review, we summarized the bioassay development of luminescence in plant cells, followed by exampling the successful cases of glowing plants transformed with diverse luminescent systems. The potential key factors to design or optimize a glowing plant were also discussed. Our review is useful for the creation of the optimized glowing plants, which can be used not only in scientific research, but also as promising substitutes of artificial light sources in the future. This article is protected by copyright. All rights reserved.

Chemical warfare agents, particularly nerve agents such as sarin, are exceptionally harmful and incredibly perilous to people. Thus, the sensitive detection of these gases is indispensable for reducing the risk of chemical weapons. Herein, we fabricated a room-temperature chemiresistive gas sensor based on two-dimensional few-layer tungsten diselenide (WSe2) nanosheets, which were prepared through a facile liquid-phase exfoliation method. The WSe2-based sensor has demonstrated sensitive and selective detection of dimethyl methylphosphonate (DMMP), which is a well-known simulant of the nerve agent sarin. The sensor based on WSe2 nanosheets revealed a high response reaching 8.91% to 10 ppm DMMP with a fast response time of 100 s. Furthermore, the sensor displayed reliable stability, excellent selectivity, and a low theoretical limit of detection of about 122 ppb. The enhanced sensing performance of WSe2 nanosheets can be ascribed to the increase of the specific surface area, which provides more active adsorption sites for DMMP molecules, thereby facilitating the charge transfer process between DMMP molecules and WSe2 nanosheets. Overall, our results indicate that two-dimensional transition metal dichalcogenide materials have the potential for the design and fabrication of high-performance nerve agent sensing devices.

Metal phthalocyanines (MPcs) have attracted great interest in the gas sensing field, but the long recovery time with hard desorption of gas has hindered their further practical application. The combination of cobalt and carboxyl groups increases the electron concentration. Herein, cobalt phthalocyanine (CoPc-COOH) modified with carboxyl groups was prepared and applied to detect nitrogen dioxide (NO

A novel quantification technique is presented for electronic nose (E-nose), which is based on a double-step strategy combined with hierarchical classifier (HC) and partial least squares regression (PLSR). With the tree structure of HC, the complexity of classifier training process can be reduced in the case of unbalanced samples. For each level of the class hierarchy, the extreme learning machine-based artificial neural network (ELM-ANN) is applied for classification. In order to improve the classification performance of ELM-ANN, the multiple time-domain features are selected as training inputs, and a novel optimization method of the number of hidden layer neurons is given. To validate the effectiveness of the presented quantification technique, an E-nose system is designed to quantify the gases including six toxic gases (hydrogen sulfide, carbon monoxide, ammonia, toluene, formaldehyde, acetone) and three kinds of binary gas mixtures. This presented hierarchical classifier has demonstrated outstanding performance for the identification of target gases, such as the macro-averaged precision for unlabeled data is improved from 80% to 92% compared with non-hierarchical classifiers. Furthermore, an excellent performance of concentration estimation is obtained utilizing PLSR, where average values of the coefficient of determination for training and test samples are equal to 0.957 and 0.927, respectively. Overall, our work demonstrates that the proposed approach is applicable in E-nose-based odor quantification.

Furfural (FUL) is substantially produced by the polymeric xylan fraction of hemicellulose with the presence of acids, and 2-methyl furan (2-MF) produced from FUL is an important biogasoline additive. Here, we report that 2-MF can be selectively formed from FUL with a 90% yield at 220 °C within 2 h over Cu0/Cu2O·SiO2 sites via a copper phyllosilicate precursor without extraneous gas. Methanol is used for in situ generating of highly pure hydrogen (92% content), and the almost CO free atmosphere avoids the poison on the Cu sites. The structure–activity relationship shows that Cu0 or Cu2O or physically mixed Cu0 and Cu2O is inactive, but the hydrogen-reduced copper phyllosilicate sample comprising abundant Cu0/Cu2O·SiO2 sites with interfaces demonstrates high activities in both reactions of methanol decomposition and FUL hydrodeoxygenation (HDO). The network for converting FUL to 2-MF includes tandem steps of FUL hydrogenation and furfural alcohol (FOL) hydrogenolysis to target 2-MF, accompanied by the side-...