Search

This paper focuses on improving the tracking accuracy for servo systems and increasing the contouring performance of precision machining. The dynamic friction during precision machining is analyzed using the LuGre model. The dynamic and static parameters in the friction model are efficiently and accurately identified using the improved Drosophila swarm algorithm based on cross-mutation. The friction tracking error can be deduced from the friction state space and an expression is derived. To compensate for the tracking error caused by friction, a feedforward compensation control is designed to avoid signal lag in traditional friction controllers. Furthermore, the factors of multi-axis parameter mismatching that impact the machining profile accuracy are analyzed for multi-axis control. An adaptive cross-coupled control-based pre-compensation strategy of contour error is designed to reduce both the tracking error and the contour error. The effectiveness of the proposed method is validated through several experiments, which demonstrate a remarkable improvement in tracking performance and contour accuracy. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Molecular Science is the property of Journal of Molecular Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Volatile oil, mainly extracted from aromatic plants, is widely used in medical, cosmetics, and other industries for its disinfection, sterilization, antioxidant, and other effects. The yield of volatile oil was influenced by plant density and harvest time. Here, two common aromatic plants, Perilla frutescens and Ysphania ambrosioide, were taken as examples to investigate the effects of plant density and harvest time on plant yield-related traits, content, and yield of volatile oil, and the oil yield was determined by steam distillation. Results showed that plant density and harvest time significantly affected the yield and quality of the two plants (p < 0.05). Increasing plant density significantly increased the dry yield and leaf dry yield of P. frutescens, while the dry yield and volatile oil content and yield of Y. ambrosioides significantly decreased, and the maximum value exhibited was at the plant density of 80 cm × 80 cm. In P. frutescens, the maximum volatile oil content was obtained at the plant density of 60 cm × 60 cm, and the maximum volatile oil yield was obtained at the plant density of 30 cm × 30 cm. The yield and volatile oil yield of these two plants increased first and then decreased with the extension of harvest time. The maximum of P. frutescens was in mid-September, and that of Y. ambrosioides was in late October to early November. Our study provides new data for improving plant volatile oil yield and commercial value by optimizing planting density and harvest time and highlights the importance of optimizing planting management mode. [ABSTRACT FROM AUTHOR]

Material composition and structural design are important factors influencing the electromagnetic wave (EMW) absorption performance of materials. To alleviate the impedance mismatch attributed to the high dielectric constant of Ti3C2Tx MXene, we have successfully synthesized core‐shell structured SiO2@MXene@MoS2 nanospheres. This architecture, comprising SiO2 as the core, MXene as the intermediate layer, and MoS2 as the outer shell, is achieved through an electrostatic self‐assembly method combined with a hydrothermal process. This complex core‐shell structure not only provides a variety of loss mechanisms that effectively dissipate electromagnetic energy but also prevents self‐aggregation of MXene and MoS2 nanosheets. Notably, the synergistic combination of SiO2 and MoS2 with highly conductive MXene enables the suitable dielectric constant of the composites, ensuring optimal impedance matching. Therefore, the core‐shell structured SiO2@MXene@MoS2 nanospheres exhibit excellent EMW absorption performance, featuring a remarkable minimum reflection loss (RLmin) of −52.11 dB (2.4 mm). It is noteworthy that these nanospheres achieve an ultra‐wide effective absorption bandwidth (EAB) of 6.72 GHz. This work provides a novel approach for designing and synthesizing high‐performance EMW absorbers characterized by "wide bandwidth and strong reflection loss." [ABSTRACT FROM AUTHOR]

Vacuum induction melting is a more energy-efficient process for the preparation of a titanium alloy with good homogeneity and low cost. But the crucial problem for this technology is in developing a crucible refractory with high stability. In the present work, a novel (Ca,Sr,Ba)ZrO3 crucible was prepared by slip casting and its performance in melting NiTi alloy was studied. The results showed that a single solid solution was formed with a homogeneous distribution of metal elements after sintering at 1500 °C. It was found that the total content of oxygen and nitrogen remaining in the TiNi alloy after melting in the (Ca,Sr,Ba)ZrO3 crucible was 0.0173 wt.%, which fulfills the ASTM standard on biomedical TiNi alloys. The good resistance of the (Ca,Sr,Ba)ZrO3 crucible to molten NiTi has a relationship with the sluggish diffusion effect of high-entropy ceramics. This study provides insights into the process of designing highly suitable crucible material for melting a NiTi alloy. [ABSTRACT FROM AUTHOR]

Fullerene is a material with good electrical conductivity and thermal stability, and its size is an important factor to influence its photoelectric property. In this work, effect of fullerene size (C20, C60, and C70) on nonlinear optical (NLO) switchable molecule diarylethene (DAE) was explored. In the aspect of molecular NLO properties, it could be found that the static first hyperpolarizability βtot of Cx‐O (x=20, 60, 70) was larger than that of Cx‐C (x=20, 60, 70), and the βtot difference between open‐ring and closed‐ring structure increased from 19 to 1431 au with the size of fullerene increased. Especially for C70‐DAE, its largest contrast of βtot values between open‐ring and closed‐ring structure suggested its superiority among three groups of NLO switchable complexes. The result could attribute to C70‐O exhibits a strong dipole characteristic, whereas C70‐C displays a weak dipole characteristic. By analyzing dynamic first hyperpolarizability, it could be found large NLO response mainly depended on molecular dipole characteristics. As a result, for C70‐DAE, βHRS of open‐ring structure was still larger than that of closed‐ring structure. However, the dynamic first hyperpolarizability βHRS of open‐ring structure was smaller than that of closed‐ring structure in both C20‐DAE and C60‐DAE. The switching efficiency was reversed. [ABSTRACT FROM AUTHOR]

In this paper, we propose a max–min fairness optimization scheme for a downlink multiuser multiple-input single-output (MISO) ultra-reliable and low-latency communication (URLLC) system assisted by an intelligence reflecting surface (IRS). In particular, we formulate a max–min fairness problem to jointly optimize the active beamforming vector at the base station (BS) and the passive beamforming vector at the IRS under the perfect channel state information (CSI). This problem is a non-convex optimization problem with highly coupled variables, making it challenging to obtain the global optimal solution. Subsequently, we propose a computationally-efficient iterative algorithm to obtain a suboptimal solution to this problem. In each iteration, we adopt methods such as the successive convex approximation (SCA) method, semi-positive definite relaxation (SDR) technology, and alternating optimization (AO) method to handle the internal optimization problem. Our simulation results reveal the following: (1) the proposed scheme provides a URLLC rate that is quite close to the Shannon rate, while also exhibiting low computational complexity; (2) the proposed scheme outperforms the random IRS scheme with a performance gain of up to 55%; (3) compare with conventional MISO systems without IRS, the proposed scheme offers a significant performance gain. [ABSTRACT FROM AUTHOR]

This study explores a novel reactive cold sintering method for improving the density of gadolinia‐doped ceria (GDC) ceramics while reducing the annealing temperature. Instead of using deionized water as an aid in conventional cold sintering, stoichiometrically mixed Ce(NO3)3·6H2O and Gd(NO3)3·6H2O precursors were added as additives during the CSP in this study. The effects of processing parameters such as sintering temperature and additive content on the relative density of the compacts were investigated using synthesized GDC and commercial GDC powders as raw materials. The results showed that with the aid of precursors, GDC ceramics were sintered up to 90% of their theoretical densities at 850°C and up to 94% at 950°C when the synthesized nanopowder GDC was used. Additionally, the sintering mechanism was investigated, and it was found that the GDC generated by the precursor reaction effectively filled the gaps between the original particles, promoting densification of the sample after cold‐pressing. [ABSTRACT FROM AUTHOR]

Ever-growing demands for zinc–air batteries (ZABs) call for the development of advanced electrocatalysts. Single-atom catalysts (SACs), particularly those for isolating non-noble metals (NBMs), are attracting great interest due to their merits of low cost, high atom utilization efficiency, structural tunability, and extraordinary activity. Rational design of advanced NBM SACs relies heavily on an in-depth understanding of reaction mechanisms. To gain a better understanding of the reaction mechanisms of oxygen electrocatalysis in ZABs and guide the design and optimization of more efficient NBM SACs, we herein organize a comprehensive review by summarizing the fundamental concepts in the field of ZABs and the recent advances in the reported NBM SACs. Moreover, the selection of NBM elements and supports of SACs and some effective strategies for enhancing the electrochemical performance of ZABs are illustrated in detail. Finally, the challenges and future direction in this field of ZABs are also discussed. [ABSTRACT FROM AUTHOR]

Pesticide creation is related to the development of sustainable agricultural and ecological safety, and molecular docking technology can effectively help in pesticide innovation. This paper introduces the basic theory behind molecular docking, pesticide databases, and docking software. It also summarizes the application of molecular docking in the pesticide field, including the virtual screening of lead compounds, detection of pesticides and their metabolites in the environment, reverse screening of pesticide targets, and the study of resistance mechanisms. Finally, problems with the use of molecular docking technology in pesticide creation are discussed, and prospects for the future use of molecular docking technology in new pesticide development are discussed. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

We investigate the effect of pure darkness and UV illumination on the corrosion process of 3Ni weathering steels involved in both marine atmospheric environments. The corrosion behavior of 3Ni steel in both environments was assessed by cyclic acceleration experiments, electrochemical measurements, morphological analysis and physical phase analysis. The results show that UV illumination affects the corrosion process through the photovoltaic effect of the corrosion products, with photoelectrons and photo-vacancies participating in the redox reaction between the substrate and the atmospheric environment, thereby affecting the corrosion rate of 3Ni steel, the physical composition of the corrosion products and the denseness of the rust layer. [ABSTRACT FROM AUTHOR]

The Smith–Purcell radiation (SPR) is a promising way for generating terahertz emission, which has tremendous application prospects. Yet, the conventional SPR schemes generally utilize the Gaussian electron beam/bunch with round cross section (also called a pencil beam) to interact with a planar grating. The shape mismatching between the electron beam and the grating essentially restricts the interaction efficiency together with the radiation intensity. To counteract this effect, we propose to use side-opening cylindrical gratings (SOCGs) to replace planar gratings. Detailed theoretical analyses using the surface-current model and mode-matching method are performed for the first time. A train of premodulated electron bunches is proposed to drive the SOCG, on which the electron bunches are further micro-bunched by interacting with the surface waves. The multi-bunched electron beam then generates multi-color coherent SPR at the superimposed harmonics of the train of bunches. Compared with that from a planar grating, the radiation intensity from the SOCG can be significantly enhanced, indicating that it is a promising way of developing high-power terahertz wave sources. [ABSTRACT FROM AUTHOR]

Porous g-C3N4 composed of nanosheets (p-gCN-NS) was synthesized through firstly grinding the hydrochloric acid-treated melamine with ammonium chloride (NH4Cl) and then calcining the mixture at 550° C for 2 h. The photocatalytic properties were determined by degrading Rhodamine B (RhB) and tetracycline (TC) aqueous solution (10 mg/L, 100 mL). Results show that the crystallinity, size and thickness of g-C3N4 in p-gCN-NS reduced dramatically compared with those in g-C3N4 sample synthesized without the addition of NH4Cl (gCN). Specific surface area of p-gCN-NS was 63.65 m2·g−1, which was 6.7 times that of gCN. After photocatalysis for 50 min, the degradation rate of RhB achieved 99.32% by p-gCN-NS (100 mg), whose reaction rate constant (k = 0.09317 min−1) was 10.6 times higher than that of gCN. p-gCN-NS also exhibited excellent photocatalytic activity for degrading colorless tetracycline aqueous solution. The significant improvement of photocatalytic performance can be credited to the reduced sized and thickness of g-C3N4, higher specific surface area and pore structure, as well as the weakened recombination rate of photogenerated electron–hole pairs in p-gCN-NS. This work provides a feasible and facile method for synthesis porous g-C3N4 composed of nanosheets with excellent photocatalytic performance. [ABSTRACT FROM AUTHOR]

Although B4C-based composites exhibit excellent comprehensive mechanical properties, the microscopic strength and toughness mechanism are still unclear. In this paper, the B4C–ZrB2–SiC composites with excellent mechanical properties were prepared at 1900 °C and 45 MPa for 1 h using vacuum hot pressing assisted by reaction sintering (VHP-RS). They included the relative density of 95.97 ~ 99.25%, the Vickers hardness of 36.76 ~ 37.26 GPa, the flexural strength of 807.34 ~ 882.24 MPa, and the fracture toughness of 5.18 ~ 6.75 MPa·m1/2. Then, the strengthening and toughening mechanism of dislocation were systematically investigated by HRTEM, IFFT, EDS-mapping, etc. The classical "bow-out" process of dislocation line and lamellar dislocation ring was observed as the feature of the Orowan strengthening. Dislocation piling up at grain boundary inhibits the initiation of dislocation sources. The dislocations near twin boundaries are blocked by twin boundaries and stacking faults. Grain boundaries containing segregated silicon, boron and zirconium are easy to gather around the dislocation to nail the dislocation. The above reasons make the composites have excellent flexural strength. Meanwhile, dislocation slips in SiC and ZrB2 grains promote plastic deformation and improve the fracture toughness of the composites. The changes of the a relative density, Vickers hardness, and b flexural strength, fracture toughness of the B4C–ZrB2–SiC composites with the increase of component content. [ABSTRACT FROM AUTHOR]

Background: Hypoxia inducible factor-1α (HIF-1α) regulates glucose metabolism during ischemia. This study investigated the effect of recombinant adenovirus HIF-1ɑ on neurological function and energy metabolism in a rat cerebral ischemia-reperfusion model. Methods: Rats were divided into four groups: sham-operated (Sham) group, cerebral ischemia-reperfusion (CIR) group, recombinant adenovirus empty vector (Ad) group, and recombinant adenovirus-mediated HIF-1α (AdHIF-1α) group. The AdHIF-1α group and the Ad group were injected with AdHIF-1α and Ad in the lateral ventricle. The mNSS was performed at post-ischemia day 0 (P0) and P1, P14 and P28. At P14, the cerebral infarct volume was compared. At P28, HE staining, Nissl stains and TUNEL staining were performed. The expression of HIF-1α, GLUT1 and PFKFB3 were evaluated by Western Blot and immunohistochemistry. High performance liquid chromatography (HPLC) was used to determine the expression of GLUT1 and PFKFB3, and the level of energy metabolites: ATP, ADP and AMP. Results: mNSS scores in the AdHIF-1α group were consistently lower than those in the CIR and Ad groups from P14 (P < 0.05) and Ad groups (P < 0.05). The cerebral infarct volume was reduced in the AdHIF-1α group compared with that in CIR group and Ad group (P < 0.05). At P28, HE showed better pathological changes in AdHIF-1α group. The number of Nissl bodies was increased in the AdHIF-1α group compared with the CIR and Ad groups (P < 0.05). The number of apoptotic cells in the AdHIF-1α group was fewer than that in the CIR and Ad groups (P < 0.05). The expression of HIF-1α, GLUT1 and PFKFB3 was significantly higher in the AdHIF-1α group compared with the CIR and Ad groups (P < 0.05). The ATP, ADP and AMP in the ischemic penumbra were also higher in the AdHIF-1α group (P < 0.05). Conclusion: HIF-lα promoted neurological function recovery and decreased cerebral infarct volume in rats after cerebral ischemia-reperfusion injury by improving energy metabolism. [ABSTRACT FROM AUTHOR]

With the aid of dry pressing method, porous mullite ceramic supports were prepared successfully using desiliconized high alumina fly ash as main raw material, kaolin and alumina as auxiliary raw materials, and spherical graphite as pore-forming agent. The microstructure, bulk density, apparent porosity, water absorption, flexural strength and permeability of the ceramic supports were affected by the graphite dosage, sintering temperature and time. The mullite ceramic support with the addition 30 wt% graphite and sintered at 1400 °C for 2 h achieved the optimum comprehensive performances, whose apparent porosity, flexural strength and permeation flux achieved 55.7%, 8.5 MPa and 3.65 mL cm−2 min−1, respectively. After spin coated with the mixing sols of silica and alumina, and calcined at 1300 °C for 1 h, a layer of integrated and smooth mullite ceramic membrane was loaded on the support, and it attained the permeation flux of 3.41 mL cm−2 min−1. The obtained porous mullite ceramic support and membrane could be used as the filter materials for waste water treatment. This work is not only conducive to eliminate the environmental pollution caused by coal fly ash, but also save the resources, such as clay and alumina. [ABSTRACT FROM AUTHOR]

Objective: To identify the prognostic indicators of esophageal adenocarcinoma (EAC) for future EAC diagnosis and treatment. Methods: The EAC dataset from The Cancer Genome Atlas was screened for differentially expressed microRNAs (miRNAs) and mRNAs associated with EAC. Weighted gene coexpression network analysis was performed to cluster miRNAs or mRNA with similar expression patterns to identify the miRNAs or mRNA that are highly associated with EAC. Prognostic miRNAs for overall survival (OS) were identified using Cox proportional-hazards regression analysis and least absolute shrinkage and selection operator based on survival duration and status. Two types of miRNAs were selected to develop a prognostic signature model for EAC using multiple Cox regression analysis. Furthermore, the signature was validated using internal validation sets 1 and 2. The receiver operating characteristic curve and concordance index were used to evaluate the accuracy of the signature and validation sets. The expression of miR-421, miR-550a-3p, and miR-550a-5p was assessed using quantitative polymerase chain reaction (qPCR). The proliferation, invasion, and migration of EAC cells were assessed using CCK8 and transwell assays. The OS of target mRNAs was assessed using Kaplan–Meier analysis. Functional enrichment analysis of the target mRNAs was performed using Metascape. Results: The prognostic signature and validation sets comprising mir-421 and mir-550a-1 had favorable predictive power in OS. Compared with the patients with EAC in the high-expression group, those assigned to the low-expression group displayed increased OS according to survival analysis. Differential and qPCR analysis showed that miR-421, miR-550a-3p, and miR-550a-5p were highly expressed in the EAC tissues and cell lines. Moreover, the downregulation of miR-421 and miR-550a-3p with inhibitor markedly suppressed the proliferation, invasion, and migration in OE33 cells compared with the negative control. A total of 20 target mRNAs of three miRNAs were predicted, among which seven target mRNAs—ASAP3, BCL2L2, LMF1, PPM1L, PTPN21, SLC18A2, and NR3C2—had prognostic value; PRKACB, PDCD4, RPS6KA5, and BCL2L2 were enriched in the miRNA cancer pathway. Conclusion: Prognostic indicators of EAC may be useful in future EAC diagnosis and treatment. [ABSTRACT FROM AUTHOR]

TiO2/Au/BDD composites with a Z-scheme structure was prepared by orderly depositing gold (Au) and titanium dioxide (TiO2) on the surface of a boron-doped diamond (BDD) film using sputtering and electrophoretic deposition methods. It was found that the introduction of Au between TiO2 and the BDD, not only could reduce their contact resistance, to increase the carrier transport efficiency, but also could improve the surface Hall mobility of the BDD electrode. Meanwhile, the designed Z-scheme structure provided a fast channel for the electrons and holes combination, to promote the effective separation of the electrons and holes produced in TiO2 and the BDD under photoirradiation. The electrochemical characterization elucidated that these modifications of the structure obviously enhanced the electrocatalytic performance of the electrode, which was further verified by the simulated wastewater degradation experiments with reactive brilliant red X-3B. In addition, it was also found that the photoirradiation effectively enhanced the pollution degradation efficiency of the modified electrode, especially for the TiO2/Au/BDD-30 electrode. [ABSTRACT FROM AUTHOR]

Hot oscillatory pressing (HOP) has been shown to be a more effective technology for sintering various material systems than hot pressing sintering due to the use of oscillatory pressure. However, the effect of oscillatory pressure parameters on the sintering behavior is not clear. In this paper, the effect of pressure amplitude, frequency, and mean pressure of oscillatory pressure on the sintering behavior was studied by using sapphire whisker reinforced zirconia ceramic composite as a model material. The obtained results were discussed by considering grain boundary sliding as a viscoelastic process. The current work would provide scientific guidance for determining optimized HOP parameters. [ABSTRACT FROM AUTHOR]

CsPbX3 (X = Cl, Br, I) semiconductor nanocrystals (NCs) have excellent optical and photoelectric properties, and are potential core materials for various photoelectric devices. However, the toxicity of Pb and instability have been the key limitations to application of NCs. Herein, using MnBr2 and MnBr2·4H2O as manganese sources, heavy Mn-doped CsPbBr3 (Mn:CsPbBr3) NCs are synthesized by high-energy ball grinding, which avoids high temperature, a large number of polar solvents and atmosphere protection required in traditional liquid phase methods. However, when MnBr2·4H2O is used as the raw material, infinite solid solution doping can be achieved, and the synthesized Mn:CsPbBr3 NCs show smaller particle size, stronger PL intensity and stability. The reason is that presence of crystal water plays a similar role to wet milling in the ball milling process, and can promote the passivation effect of oleylamine (OAm) on nanocrystal defects and the connection between them. In addition, a simple, easy-operating and beneficial to commercial production method for the preparation of Mn:CsPbBr3 NCs/EVA flexible films is proposed, which can effectively improve the stability of Mn:CsPbBr3 NCs. This study is expected to provide an effective way for the synthesis and stability improvement of CsPbX3 NCs doped with different ions. [ABSTRACT FROM AUTHOR]

Due to their special appearance, spherical α‐Al2O3 nanoparticles play an important role for obtaining high‐performance structural and functional ceramics. However, there are still problems such as easily agglomerates to form worm‐like structures at high temperatures and difficult availability of spherical nanoparticles. In this study, spherical α‐Al2O3 nanoparticles with high dispersion were prepared by a combination of a microwave hydrothermal method and an addition of nano‐Al particles as seeds. First, spherical amorphous alumina precursors were synthesized by the microwave hydrothermal method at 100°C for 30 min using Al2(SO4)3·18H2O, Al(NO3)3·9H2O, and urea, as raw materials, and then spherical α‐Al2O3 nanoparticles with a diameter of about 66 nm were acquired after calcined the precursor at 1050°C for 90 min by adding nano‐Al seeds, which reduced the calcination temperature by 50°C and holding time by 30 min compared to that without seeds. Kinetic analysis shows that 5 wt.% nano‐Al seeds can reduce the activation energy of crystalline transition of γ‐Al2O3 to α‐Al2O3 from 516.51 to 474.37 kJ/mol. Moreover, the microscopic mechanism of nano‐Al particles as seeds was investigated. The characterizations of sintering properties show that spherical α‐Al2O3 nanoparticles facilitate the acquisition of uniform microstructure for resulting ceramic and the fracture modes include both intergranular and transgranular fractures. [ABSTRACT FROM AUTHOR]

All‐inorganic perovskite nanocrystals (NCs) have been widely used in many fields due to their excellent photoelectric properties. However, the instability of their structure and the high lead content need to be solved. Herein, the concept of "High‐entropy" is introduced into NCs to prepare High‐entropy perovskite Cs(Pb1/3Mn1/3Ni1/3)Br3 NCs by high‐energy ball milling method. The effects of milling time and doping ratio of B‐site elements on the structure and performance of perovskite NCs are studied. It is found that Mn2+ and Ni2+ successfully enter the lattice of Pb2+ to form "High‐entropy" perovskite NCs. In addition, compared with Cs(Pb0.72Mn0.14Ni0.14)Br3 NCs, Cs(Pb1/3Mn1/3Ni1/3)Br3 NCs have greater luminous intensity and stability, which because of the enhancement of band gap and valence bonds. Furthermore, photoluminescence intensity at 515 nm increase obviously when Cs(Pb1/3Mn1/3Ni1/3)Br3 NCs are heated at 120 °C. This is due to the lattice distortion effect brought about by ion doping. This study is expected to provide an effective way for synthesis and stability of all‐inorganic perovskite NCs doped with more kinds of different ions. Moreover, it also lays the foundation for the introduction of "High‐entropy" into perovskite functional ceramics. [ABSTRACT FROM AUTHOR]

g–C3N4 nanosheets were first synthesized by calcining the mixture of hydrochloric acid-pretreated melamine and ammonium chloride. Then, by the aiding of solvothermal method and hydrofluoric acid as morphology modifier, 001-TiO2/g–C3N4 (TCN-X, X = 5 , 3, 2, 1) nanocomposites were synthesized using g–C3N4 nanosheets and tetrabutyl titanate, with the mass ratio of g–C3N4 to TiO2 was 5:1, 3:1, 2:1 and 1:1, respectively. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption method, ultraviolet–visible diffuse reflectance spectrum, photoluminescence spectrum, etc. Their photocatalytic properties were evaluated under visible light irradiation with rhodamine B (RhB) as the target pollutant. The results reveal that the TCN-3 composites had a large specific surface area of 67.38 m2/g and consisted of g–C3N4 nanosheets and anatase TiO2 crystals about 10–20 nm in size. The (001) crystal planes of TiO2 can be easily observed in TCN-X composites. All TiO2/g–C3N4 composites exhibited excellent photocatalytic activity compared with the pure g–C3N4 did. The photocatalytic property of TCN-X samples varied with the mass ratio of g–C3N4to TiO2, and TCN-3 presented the optimum photocatalytic performance. In total, 50 mg of TCN-3 completely degraded 50 mL and 100 mL of RhB solution (10 mg/L) in 15 min and 40 min, respectively. The reaction rate constant of TCN-3 was 6.7 times as large as that of pure g–C3N4. TCN-3 also presented outstanding activity for the photocatalytic degradation of the colorless tetracycline solution. The significant improvement in photocatalytic activity of TCN-3 was attributed to the evenly distribution of TiO2 on g–C3N4, the enhanced specific surface area and the construction of 001-TiO2/g–C3N4 heterojunction between the g–C3N4 nanosheets and the (001) crystal planes of anatase TiO2, which greatly reduced the recombination rate of the photo-generated electron and hole. In this work, the g–C3N4 nanosheets were obtained by simple mixing and calcination of ammonium chloride and acid-treated melamine. Then, using tetrabutyl titanate as the precursor and hydrofluoric acid to expose the 001 crystal face of TiO2, 001-TiO2/g–C3N4 composite materials with different mass ratios were synthesized by simple hydrothermal method. The composite exhibited excellent photocatalytic performance and degraded RhB within 15 min. The rate constant of TiO2/g–C3N4 composite is 6.7 times that of pure g–C3N4. [ABSTRACT FROM AUTHOR]

Steerable coherent terahertz wave emission is attractive for various applications. Aiming for that, we propose to use a uniformly moving sheet electron beam to drive a 2-D composite array of sub-wavelength holes (SHs). Each SH is an independent resonator in the terahertz region, and a set of SHs with different orientations form a composite radiating unit. Excited by the electron beam, the emissions from all the units in the array constructively interfere in specified directions via the combination of the famous Cherenkov radiation (CR) and Smith–Purcell radiation (SPR) effects, leading to a directional coherent terahertz radiation, which can be real-timely steered by rotating the array. The detailed theoretical analyses of this radiation are performed and verified by simulations. This radiating scheme promises novel types of multi-functional terahertz sources and devices. [ABSTRACT FROM AUTHOR]

Oxygen reduction reaction (ORR) occupies a pivotal position in fuel cell applications, and it is a challenge to obtain highly durable ORR catalysts. Herein, porous cobalt oxide microsphere growing at the surface of on nitrogen-doped graphitized-nano-diamond (CoOx/N-GND) was prepared using hydrothermal and subsequent heat treatment process. Porous cobalt oxide of high specific surface area could expose more surface Co2+ that act as active sites than bulk one does. The doping of nitrogen also promotes the catalytic activity. Besides, nano-diamond (ND) of sp3 hybrid structure was used as an electronic conduction carriers of ultrahigh stability to improve the durability of catalytic composite. Prepared CoOx/N-GND shows a satisfactory half-wave potential of 0.82 V (versus RHE), which is close to that of Pt/C (0.85 V), an excellent methanol tolerance and a lower activity loss after 5000 cycles. These merits inspire the application of CoOx/N-GND as the cathode of Zn-air battery and the battery performance was evaluated in this work. In general, this work highlights an innovate approach to design and prepare highly durable catalyst. [ABSTRACT FROM AUTHOR]

The present research explored how foreign language listening anxiety (FLLA) affected Chinese university students' English listening test performance and how proficiency and gender mediated the effects of FLLA on the latter. Two different populations from two universities in China answered the 20-item Foreign Language Listening Anxiety Scale (FLLAS) as well as a demographic questionnaire and took an English listening test. Analyses of the collected data revealed the following major findings: (a) Five latent factors underlay the FLLAS, (b) when working alone, FLLA significantly negatively predicted students' English listening test performance, and (c) when working with proficiency and gender, English proficiency level, gender and FLLAS2 (proficiency in English listening) significantly predicted students' English listening test performance. These findings confirm the negative effects of FLLA on students' English listening test performance. They also indicate that English proficiency and gender mediate FLLA's effects on the latter, with English proficiency not only directly but also indirectly affecting the latter. [ABSTRACT FROM AUTHOR]

Particle accelerator on chip with high acceleration gradient has been an unremitting goal of researchers. Dielectric laser accelerator (DLA) is a possible candidate to achieve this goal. However, due to the limitation of dielectric breakdown, it is difficult for the available DLAs to reach an acceleration gradient as high as 1 GV m−1 since a long-duration multi-cycle laser pulse with high fluence have to be used. Here we propose to use a few-cycle laser pulse to drive a DLA based on the inverse Cherekov radiation effect. It significantly reduces the required pulse duration and the laser fluence, remarkably increasing the achievable acceleration gradient. Moreover, by using a cascade acceleration scheme, we realize a high energy-gain acceleration for low-energy electrons in a microscale device by simulation, which paves the way for the development of a fully on-chip particle accelerator. [ABSTRACT FROM AUTHOR]

Fabry–Pérot (FP) resonators with metallic subwavelength grooves or holes, which have been extensively applied in optical region, have recently attracted increasing interest for terahertz wave generation and manipulation. However, the practices of such resonators in the terahertz region are greatly restricted by the low energy-capacity and by the difficulty of manufacturing high-aspect-ratio grooves/holes. Here we illustrate a kind of terahertz FP resonator formed by a cluster of coupled grooves with low-aspect-ratio, which has much higher energy-capacity, higher quality-factor and is much easier to fabricate than one formed by a single uncoupled-groove. Using free-electron beams to excite an array of such FP resonators, coherent terahertz emission can be achieved, the intensity of which is more than an order of magnitude higher than that from an array of uncoupled-grooves, affording a promising way for high-power and coherent terahertz wave generation. [ABSTRACT FROM AUTHOR]

This paper examines the applicability of four failure criteria applied to layered rocks, namely, Pariseau's model, linear empirical equation, nonlinear empirical equation (LEE and NLEE), and Jaeger's plane-of-weakness model (JPW). A database comprising 282 uniaxial compressive strength (UCS) tests and 1,273 triaxial tests conducted worldwide on layered rocks is compiled. Pariseau's model is classified as a continuous function, and LEE and NLEE, as well as JPW, are classified as piecewise functions. Nonlinear least squares and traversing methods are used to determine the global minima of the material coefficients in the two types of functions. The goodness of fit of these criteria for the database is evaluated. Two statistical parameters, namely, regression coefficient (R2) and mean absolute percentage error (MAPE) are used for precision assessment. The aforementioned methods and the criteria are further used for evaluating the surrounding rock stability of the eastern slope of Yanshan iron open-pit and the underground powerhouse of the Jinping I hydropower station. The results show that (1) Pariseau's model is not suitable for layered rocks when n = 2, and the fit is worst in the condition of insufficient triaxial data when n = 1; (2) the MAPE of the empirical equation (LEE and NLEE) is within 20%, with the best predictive accuracy under medium to low confining pressures, and the MPAE of JPW is within 40%, with the best predictive accuracy under high confining pressures; and (3) calculation of the damage area of the slope and underground powerhouse and comparison with the actual damage on the site verify that the empirical equation has the best engineering prediction accuracy under medium to low confining pressure conditions. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of pollutants has been proved to be an effective strategy for wastewater treatment. Herein, TiO2 nanoparticles were synthesized on a Ti3C2 matrix by in situ growth, forming Z-scheme TiO2@Ti3C2/Cd0.5Zn0.5S (TO/CZS) multilevel structured nanocomposites via one-step hydrothermal route. The effects of hydrothermal temperature and Cd0.5Zn0.5S content on microstructure and properties of composites were assessed. TO/CZS nanocomposites were probed into phase composition, morphological and optical properties with x-ray diffractometer, infrared radiation, scanning electron microscope and UV–vis reflective spectra. Following the hydrothermal reaction at 160 °C for 12 h, TiO2 nanoparticles of 30 nm in diameter were generated in situ on Ti3C2 lamina and Cd0.5Zn0.5S particles were evenly distributed on the Ti3C2 matrix. The photocatalytic activity of TO/CZS composites were evaluated, which found that degradation rate constant (k = 0.028 min−1) of TO/CZS-40 on Rhodamine B was 5.19 times that of pure TiO2 and 4.48 times that of Cd0.5Zn0.5S. Through anchoring Ti3C2 as an electron transition mediator and combination with TiO2 and Cd0.5Zn0.5S, the new Z-scheme between TiO2 oxidized by Ti3C2 and Cd0.5Zn0.5S establishes a multilevel structure of separating electron-hole pairs. This work demonstrates a valid way to control electrons and hole transfer directions efficiently through designing multilevel semiconductor structural designs. [ABSTRACT FROM AUTHOR]

Background: Recessive mutations in ETFDH gene have been associated with Multiple Acyl-CoA dehydrogenase deficiency (MADD). The late-onset MADD is often muscle involved, presenting with lipid storage myopathy (LSM). The symptoms of LSM were heterogeneous and definite diagnosis of this disease depends on the pathology and gene test. Methods: Neurological examination, muscle biopsy, and MRI examinations were performed in a patient with a novel missense ETFDH mutation. Results: We describe a patient with lipid storage myopathy complicated with skin damage. In addition, the next generation revealed a novel missense mutation (c.970G > T, p.Val324Leu) in exon 8, which was predicted to be a disease-causing mutation by Mutation-taster, and destroy the function of the protein by Sift. Conclusion: These findings expand the known mutational spectrum of ETFDH and phenotype of MADD. [ABSTRACT FROM AUTHOR]

Herein, an octanuclear complex [Mn8(μ4-O)4(phpy)8(MeOH)4]·MeOH·H2O based on 5-(2-hydroxyphenyl)-3-pyrazole (HphpyH) has been successfully synthesized and characterized. The compound can self-assemble to form nanoparticles (NPs) by nanoprecipitation with PEG-5000. [Mn8(μ4-O)4(phpy)8(MeOH)4]·MeOH·H2O NPs have a low IC50 (half maximal inhibitory concentration) of only 44 μg/mL (2.3 μM) on HeLa cells. The results show that [Mn8(μ4-O)4(phpy)8(MeOH)4]·MeOH·H2O NPs are able to inhibit cell proliferation and migration in vitro. [ABSTRACT FROM AUTHOR]

The interaction between benthiavalicarb-isopropyl and human serum albumin was studied by ultraviolet-visible absorption, fluorescence, synchronous fluorescence, three-dimensional fluorescence, circular dichroism spectroscopies and molecular docking. The results revealed that the effect of benthiavalicarb-isopropyl on human serum albumin was static quenching. The number of binding sites, binding constants, and binding distance were obtained. The interaction of benthiavalicarb-isopropyl to human serum albumin was mainly through hydrogen bond and van der Waals force. The conformation of human serum albumin changed slightly. The interaction details were studied by molecular docking method. This study elucidated the mechanism of the interaction between benthiavalicarb-isopropyl and human serum albumin. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents electrolytic capacitorless AC/DC LED driver. It adopts Boost–Buck topology, through modulation of the conduction time T on and the change of input current reference, to reduce the instantaneous input and output power difference, so a smaller film capacitor can be used instead of the electrolytic capacitor. Therefore, LED driver power life has been effectively improved. The Buck converter operates in the inductor current discontinuous conduction mode to achieve constant output current by controlling the peak current. The control IC is fabricated in TSMC 0.35- μ m 5-V/650-V CMOS/LDMOS process, and verified in a 72-V/150-mA circuit prototype. The test results show that when the range of input voltage is 175–264 Vac, the efficiency of the system is 83%, the voltage linear regulation is ± 1 %, the load regulation is ± 0. 5 %, and the electrolytic capacitor is replaced by 470-nF CBB capacitor under the condition that the power factor is above 0.7. Therefore, the design of the control chip in the LED driver has a very good application prospect. [ABSTRACT FROM AUTHOR]

Dense ZrB2‐SiC‐Al3BC3 ultra‐high temperature ceramic composite was fabricated by hot pressing sintering at 1900°C for 1 hour under a pressure of 20 MPa using Zirconium diboride (ZrB2) as the raw material and a powder mixture of SiC, B4C, Al, and carbon as the sintering additive. Al and B4C underwent in situ reaction with carbon powder to produce Al3BC3, which promoted the densification of ZrB2 ceramic. SiC grains were found to be elongated during sintering. The ZrB2‐SiC‐Al3BC3 composite exhibited excellent mechanical properties, such as high flexural strength of 589 ± 147 MPa and fracture toughness of 7.81 ± 1.09 MPa m1/2. Oxidation behavior of the ZrB2‐SiC‐Al3BC3 composite was studied in air at 1500°C for 1 hour. A continuous layer of oxides consisting of a mixture of SiO2, Al2SiO5, and Al2O3 was formed on the surface of the ZrB2‐SiC‐Al3BC3 composite. This layer of oxides efficiently prevented oxygen from diffusing into the specimens during oxidation, which improved the oxidation resistance of the ZrB2 ceramics. [ABSTRACT FROM AUTHOR]

Botulinum toxin A (BTX-A) is a promising therapeutic modality against trigeminal neuralgia (TN) with certain controversies pertaining to its application. To provide further information on factors influencing the treatment outcomes of BTX-A, a retrospective study with 152 patients with TN treated with BTX-A was performed. The starting time and duration of the therapeutic effect, as well as side effects, of BTX-A in the treatment of TN were analyzed by sex, age, course of disease, number of branches and injected dose. A total of 136 patients exhibited symptom improvement within 2 weeks following BTX-A treatment as evaluated using a visual analog scale (VAS). The effect of BTX-A was sustained throughout the initial 6 months of the follow-up and was demonstrated to persist for as long as 28 months. Female sex, short disease course and high injection dose (>70 units) were associated with lower long-term VAS scores. Patients receiving short-term medium-(50–70 units) or high-dose injections were more likely to be completely cured. Patients with a median disease course (1–10 years) or multiple branches were more likely to exhibit facial asymmetry. Based on the stratified analysis, female patients with a median disease course (1–10 years) exhibited a higher incidence of side effects and male patients achieved better treatment outcomes with high BTX-A doses. BTX-A effectively alleviated patients with TN in both short or long term, although the treatment efficacy may depend on patient characteristics. [ABSTRACT FROM AUTHOR]

In this work, the hierarchical NiCo2O4 self-assembled by lamellar flakes were successfully synthesized by a simple solvothermal route and subsequent thermal treatment. The composition and microstructure of the hierarchical NiCo2O4 were characterized by XRD and SEM, respectively. The microwave absorption properties were also evaluated. An optimum reflection loss (RL) of − 45.5 dB at 4.6 GHz with a composite thickness of 4.2 mm and effective bandwidth (RL < − 10 dB) of 7.7 GHz were obtained. The excellent electromagnetic wave absorption property of the hierarchical NiCo2O4 is due to the conduction loss and dielectric loss of NiCo2O4, the hierarchical structure could also enhance the microwave absorbing properties by the strong multi-reflections and scattering of microwave between stacking layers. [ABSTRACT FROM AUTHOR]

Cytochrome c oxidase 20 (COX20)/FAM36A encodes a conserved protein that is important for the assembly of COX, complex IV of the mitochondrial respiratory chain. A homozygous mutation (p.Thr52Pro) in COX20 gene has been previously described to cause muscle hypotonia and ataxia. In this study, we describe two patients from a non-consanguineous family exhibiting autosomal recessive sensory-dominant axonal neuropathy and static encephalopathy. The whole-exome sequencing analysis revealed that both patients harbored compound heterozygous mutations (p.Lys14Arg and p.Trp74Cys) of COX20 gene. The pathogenicity of the variants was further supported by morphological alternations of mitochondria observed in sural nerve and decreased COX20 protein level of peripheral blood leucocytes derived from the patients. In conclusion, COX20 might be considered as a candidate gene for the complex inherited disease. This observation broadens the clinical and genetic spectrum of COX20-related disease. However, due to the limitation of a single-family study, additional cases and studies are definitely needed to further confirm the association. [ABSTRACT FROM AUTHOR]

By employing an oriented external electric field as a catalyst or inhibitor, the model reactions of the hydroboration of terminal olefins with the simplest borane were studied for the first time. The electric fields used in this work are oriented in directions parallel and perpendicular to the C=C bond in the olefins to explore their influence on regioselectivity and barrier height. It was exciting that the first hydroboration of ethylene in an electric field along the parallel direction perfectly proved the relationship between the positively polarized carbon atom on the C=C bond and the regioselectivity of this reaction. A very significant finding is that the dominant Markovnikov hydroboration of propene occurred when the external electric field was along its flipped direction. And the kinetic calculations showed that this extent of Markovnikov hydroboration would give an obvious advantage with rising fields, because the ratio kAM : kM had decreased to 0.36 when the field was up to −70 (×10−4) a.u. Additionally, all of the hydroborations of olefins (whether of ethylene or propene) with borane just changed their barrier heights instead of their regioselectivity when the external electric field was oriented in the direction perpendicular to the C=C bond. The model reaction in this work is meaningful for exploring more complicated hydroboration reactions of olefins experimentally. [ABSTRACT FROM AUTHOR]

Kaolinite/TiO2 composites were prepared by using sol-gel method and raw kaolin, pretreated kaolinite and tetrabutyl titanate as the main raw materials. X-ray diffractometer, field-emission scanning electron microscope and infrared spectrometer analysis were carried out to characterize the phase composition and microstructure of the samples. The photocatalytic performance of the kaolinite/TiO2 composites were evaluated by degrading the methylene blue (MB) and phenol aqueous solution, respectively. The results show that intercalation and exfoliation reduced the size and thickness of kaolinite particles. Acid treatment improved the distribution and the loading quantity of TiO2 grains. When the kaolinite/TiO2 composites were calcined at 500 °C, the tetragonal structure of anatase particles of 30-100 nm in size were obtained, but the exfoliated kaolinite crystals were damaged. The degradation rate of MB increased gradually with the extension of photocatalytic reaction time and the enhancement of photocatalyst dosage. The adsorption performance of acid-treated kaolinite/TiO2 composite (AKT) was nearly the same as that of raw kaolin/TiO2 composite (RKT), but that of the exfoliated kaolinite/TiO2 composite (EKT) was the most excellent. The photocatalytic performance of AKT and EKT were better than that of RKT, and AKT exhibited the optimum property. Under a certain photocatalyst dosage and photocatalysis time, the absorption rate and the degradation rate decreased gradually with the enhancement of initial concentration of MB. Similar result was also acquired for the degradation of phenol. Both the acid treating and the exfoliating to kaolinite enhanced the photocatalytic performance of the kaolinite/TiO2 composite photocatalysts, but acid treatment may be more helpful to the preparation of high performance kaolinite/TiO2 composite photocatalyst. Natural kaolinite particles were pretreated by acid treating or intercalating-exfoliating.Kaolinite/TiO2 composites were prepared by sol-gel method.Pretreatment of kaolinite improved the photocatalytic performance of kaolinite/TiO2 composite. [ABSTRACT FROM AUTHOR]

Background: Kufs disease type B (also termed CLN13), an adult-onset form of neuronal ceroid lipofuscinosis (NCL), is genetically heterogeneous and challenging to diagnose. Recently, mutations in cathepsin-F have been identified as the causative gene for autosomal recessive Kufs disease type B. Results: Here, we report a sporadic case of Kufs disease type B with novel compound heterozygous mutations, a novel missense mutation c.977G>T (p.C326F) and a novel nonsense mutation c.416C>A (p.S139X), in the cathepsin-F gene. The magnetic resonance imaging findings were consistent with those demonstrated in adult neuronal ceroid lipofuscinosis: diffuse cortical atrophy, mild hyperintensity and reduction of the deep white matter on T2-weighted images. A skin biopsy was negative for abnormalities. Conclusions: Altogether, our findings broaden the mutation database in relation to the neuronal ceroid lipofuscinosis, and the clinical diagnosis of Kufs disease type B was confirmed. [ABSTRACT FROM AUTHOR]

Kaolinite nanotubes (KNTs) were prepared by using a solvothermal method and natural kaolin as raw material. Magnetic kaolinite nanotubes (MKNTs), whose mass ratio of Fe3O4 to KNTs is 1:5, were prepared by the chemical co-precipitation method. The methylene blue (MB) adsorbing ability of the as received materials was studied. The chemical and mineral composition, structure and morphology of samples were investigated using X-ray fluorescence spectrometry analysis, X-ray powder diffraction, field-emission scanning electron microscopy, infrared spectroscopic analysis and N2 adsorption-desorption isotherm. A set of experiments were carried out under different conditions of contact time, adsorbent dosage, temperature, initial MB concentration and pH value to investigate the adsorption behavior of MB onto MKNTs. 94.20% of MB was removed by adding 0.04 g MKNTs into a 10 mg L−1 solution (50 mL) at 298 K for 20 min. The experimental adsorption data followed a pseudo-second-order kinetic model and Langmuir isotherm. MKNTs showed excellent magnetic separation property and reusability. [ABSTRACT FROM AUTHOR]

Vascular dementia (VaD) is the second most common dementia worldwide. Unlike Alzheimer's disease, VaD does not yet have effective therapeutic drugs. Harpagoside is the most important component extracted from Harpagophytum procumbens, a traditional Chinese medicine that has been widely used. The neuroprotective effects of harpagoside have been studied in Aβ- and MPTP-induced neurotoxicity. However, whether harpagoside is protective against VaD is not clear. In this study, with the use of chronic cerebral hypoperfusion rats, a well-known VaD model, we demonstrated that chronic administration (two months) of harpagoside was able to restore both the spatial learning/memory and fear memory impairments. Importantly, the protective effects of harpagoside were not due to alterations in the physiological conditions, metabolic parameters, or locomotor abilities of the rats. Meanwhile, we found that harpagoside suppressed the overactivation of PTEN induced by CCH by enhancing PTEN phosphorylation. Furthermore, harpagoside elevated the activity of Akt and inhibited the activity of GSK-3β, downstream effectors of PTEN. Overall, our study suggested that harpagoside treatment might be a potential therapeutic drug targeting the cognitive impairments of VaD. [ABSTRACT FROM AUTHOR]

Aim of the study:To report a novel mutation in the electron transfer flavoprotein dehydrogenase (ETFDH) gene in an adult patient with late-onset riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency. Materials and methods:The genomic DNAs from a patient whose main clinical presentations are muscles weakness and hypoglycemia was analysed. Results:The patient was identified to carry compound heterozygous mutations in ETFDH gene. Two missense mutations c.814 G > A and c.389 A > T were found. Conclusion:This is the first report of c.814G > A mutation in ETFDH in adult patient with MADD. [ABSTRACT FROM AUTHOR]