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With the requirement for self-powering functionality in wearable electronics, a small power range flexible photovoltaic micro-power system is evidently needed. Furthermore, non-flexibility, large volume/weight, power consumption constraints, and cost considerations make it impractical to directly use the large power range complex maximum power point tracking (MPPT) algorithm and hardware in wearable electronics. This work aims to design a fully flexible photovoltaic micro-power system for reliable energy supply within the low power range for wearable electronics. In this study, a customized fractional open circuit voltage (FOCV) algorithm and a performance-matching DC-DC converter are designed, and then integrated with a flexible perovskite solar module to develop a fully flexible photovoltaic micro-power system. Indoor and outdoor experiments are conducted to evaluate its performance. The designed MPPT system achieves a high tracking accuracy of 99.25% at a power of 0.539 W with a fast tracking time of 0.20 s, which is an effective improvement over the traditional algorithms. These values are 97.8% and 0.21 s under shaded lighting conditions. The MPPT system is lightweight (4.6 g) with a size of <3 × 3 cm2. Tracking experiments with flexible solar modules after bending also demonstrate the flexibility of the system, which also shows the high utilization and fast response capability for small power range photovoltaic outputs. The fully flexible photovoltaic micro-power system demonstrates great potential for future wearable electronics and expands the way to efficiently harvest solar energy in highly adaptive and dynamic applications. • A customized MPPT algorithm and hardware is proposed. • The customized MPPT exhibits a high power tracking accuracy of 99.25% and a fast tracking time of 0.20 s. • A fully flexible photovoltaic micro-power system is developed by integrating a flexible MPPT and a flexible solar module. [ABSTRACT FROM AUTHOR]

Achieving efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) simultaneously in the electrocatalytic water-splitting is essential to achieve a green hydrogen economy. However, a rational catalyst design still faces great challenges due to the slow kinetic limitations such as electron transfer at the electrode-electrolyte interface. Herein, a porous 3D CoPt 3 /a-FCWO-NS heterostructures was formed by morphology modulation and interfacial engineering. Notably, the catalyst requires only 1.51 V to achieve 10 mA cm−2 in 1 M KOH, and a commercial 1.5 V cell can drive the overall water-splitting with excellent stability. DFT combined with XPS results reveal the electron transfer between CoPt 3 and FeCoW oxides. Due to the ensemble effect CoPt 3 exhibits an electron deficient state moderating the slow kinetics of the OER process. Furthermore, the substrate FeCoW oxides modulates the d -band position of CoPt 3 , and the suitable adsorption energy for hydrogen-containing intermediates makes CoPt 3 /a-FCWO favorable for the HER process. [Display omitted] • A new strategy to synthesize porous ultrathin nanosheets with crystalline-amorphous heterostructure. • Morphology modulation and interfacial engineering to improve the catalytic activity of materials. • DFT combined with XPS verified the electron transfer between heterogeneous interfaces. • Only a 1.5 V commercial battery to perform the overall water-splitting is required. [ABSTRACT FROM AUTHOR]

This paper develops a new combined technology to fabricate complex 3D microstructure based on micro milling and micro sinking electro-discharge machining (micro-SEDM). Graphite microform electrode is in-situ prepared by micro milling and subsequently used for micro-SEDM, integrating the advantages of two processes. Material removal rate (MRR) and electrode wear ratio (EWR) are experimentally investigated to determine proper parameters for different micro-SEDM performances. Three different machining strategies including single, double and treble micro-SEDM are adopted to fabricate 3D microstructure. The surface roughness, size accuracy, machining duration and cost of micro-cavities, and electrode wear under different strategies have been compared. The results show that treble micro-SEDM produces superior surface quality with 0.83 μm Ra and size accuracy with ≤ 28.05 μm tolerance. The proposed method broadens the machining flexibility and capability of micro-fabrication techniques. [ABSTRACT FROM AUTHOR]

This paper presents a hybrid process combine micro reciprocated wire-EDM which uses reciprocated travelling wire with 50 μm diameter as tool electrode, with the precision forging, achieving the economical and high-efficiency sustainable production of micro gears. A micro gear mold with 0.1 mm module and 10 tooth number is devised, and the 14.5 μm mold fit clearance is determined by analyzing the established mold matching model and conducting the numerical simulation of precision forging. During the micro reciprocated wire-EDM of micro gear mold from SKD11, the basic experiments are performed to study the effect of the main parameters on machining accuracy and productivity, and whilst the proper machining parameters are obtained. The micro gear punch and die are successfully fabricated by micro reciprocated wire-EDM, showing good surface quality with 0.90 μm and 0.83 μm Ra respectively, and low dimensional deviations of ≤1.3 μm and 2.1 μm respectively. Finally, the precision forging of the micro gears are conducted on ultrafine grained (UFG) high purity copper by the machined micro gear mold. The forged micro gears have high forming precision with ≤4.1 μm deviation from the micro gear mold and smooth surface with 0.86 μm copied from the micro gear die cavity, verifying the feasibility of the proposed method for the sustainable production of micro gears. [ABSTRACT FROM AUTHOR]

Beryllium copper alloys are the ideal materials to fabricate the supporting parts owing to their excellent physical and chemical properties. Many high aspect ratio micro-holes are often required to realize the special missions. However, they were not easily fabricated by the traditional machining methods owing to the materials' mechanical strength. Here, we presented a high efficiency method for drilling high aspect ratio micro-holes on C17200 beryllium copper alloy by combining deionized water based micro-EDM and in situ PMEDM with boron carbide additives. The machining parameters were systematically investigated and optimized to realize the ever high aspect ratio of 23.26 at the holes' diameter of 215 μm. The surface quality of the micro-hole was improved further by in-situ PMEDM, which was demonstrated by the decreasing of surface roughness (Ra) from 2.65 μm to 0.92 μm. Our method will open an avenue to fabricate high aspect ratio micro-holes on C17200 with high efficiency. [ABSTRACT FROM AUTHOR]

Catalysts with amorphous structures have shown excellent performance in electrocatalytic water oxidation, but it remains a challenge to prepare efficient catalysts using simple methods while maintaining high yields. Herein, amorphous Fe x Co y W z oxides nanoparticles were prepared by a one-step co-precipitation method, and the Fe content was optimized to ensure efficient water oxidation. The prepared Fe 0.05 Co 0.09 W 0.61 O 0.25 had the best OER performance with a yield of 95.6% when the Co and Fe feeding ratio was 2:1. The Fe 0.05 Co 0.09 W 0.61 O 0.25 possessed an overpotential of 267 mV at 10 mA cm−2 with a small Tafel slope of 39.4 mV dec−1. The activation energy at 1.5 V is only 49.4 kJ mol−1, and Faraday efficiency is close to 100%. The water oxidation performance of the two-electrode test shows that the voltages at 10 mA cm−2 are only 1.50 V. In addition, it still maintained high activity after 72 h of chronoamperometry test, which exhibits excellent water oxidation performance among similar non-precious transition metal catalysts. Therefore, the present work provides a simple and easy way to prepare high-activity and high-yield transition metal amorphous electrocatalysts. [Display omitted] • The simple method successfully prepared high performance amorphous Fe 0.05 Co 0.09 W 0.61 O 0.25. • Fe modulates the electronic configuration and morphology of CoWO 4. • The optimal ratio of Fe doping into CoWO 4 is regulated. • Co acts as the main catalytic site in the OER process instead of Fe. [ABSTRACT FROM AUTHOR]

Abstract: Erythropoietin (EPO) is a glycoprotein hormone, expressed mainly in fetus liver and adult kidneys. EPO plays an important role in enhancing red blood cell formation in bone marrow under hypoxia. Plateau zokor (Myospalax baileyi), an subterranean burrowing endemic rodent inhabiting areas of 2 800–4 200m above sea level on Qinghai–Tibet Plateau, is a typical high hypoxia tolerant mammal with high ratio of oxygen utilization in adaptation to the harsh plateau environment. To investigate the possible mechanisms of adaptation of plateau zokor EPO to high altitude, the complete cDNA and amino acid sequences of plateau zokor EPO have been described. Phylogenetic tree of Epo showed the convergence of the Spalax and Myospalax, indicating that, the convergent evolution was driven by similar hypoxic ecological niches. Our results showed that some common sites under positive selection in zokor (116M and 144A) and Spalax (102R, 116M, 144A and 152P) are the important sites for Epo biological activity. This study thus reports a gene level observation which may be involved in adaptation to underground life at high altitude. [Copyright &y& Elsevier]

Abstract: A new micromachining method for the fabrication of micro-metal structures by using micro-reversible electrical discharge machining (EDM) was investigated. The reversible machining combines the micro-EDM deposition process with the selective removal process, which provides the ability of depositing or removing metal material using the same micro-EDM machining system. From the discharge mechanism of micro-EDM, the process conditions of micro-EDM deposition were analyzed firstly. Using the brass and steel materials as a tool electrode, the micro-cylinders with 200μm in diameter and height-to-diameter ratio of more than 5 were deposited on a high-speed steel surface. Then the machining procedure was transformed easily from deposition to selective removal process by switching the process conditions. Different removal strategies including micro-EDM drilling and micro-EDM milling were used in the machining. Micro-holes with 80μm in diameter are drilled successfully in the radial direction of the deposited micro-steel cylinder. Also, a brass square column with 70μm in side length and 750μm in height, and a micro-cylinder with 135μm in diameter and 1445μm in height are obtained by using micro-EDM milling. Finally, the characteristics of the deposited material were analyzed. The results show that the material components of a deposited micro-cylinder are almost the same as those of the tool electrode, and the metallurgical bonding has been formed on the interface. In addition, the Vickers-hardness of 454Hv of the steel deposited material is higher when compared to the hardness of 200Hv of the raw steel electrode. [Copyright &y& Elsevier]

Lunar water ice resources are important space assets for human survival and sustainable living on the Moon. Detection data indicates that the permanently shadowed regions at the lunar poles contain water ice resources. The efficiency of in-situ extraction of lunar water ice resources depends on its volatile characteristics. In the context of extraction and utilization of water ice resources in the permanently shadowed regions, the sublimation and diffusion processes of lunar water ice are investigated by combining the theory of pure ice sublimation with the fractal theory of porous media. On this basis, a volatilization model for lunar water ice is established to examine the effect of temperature, relative density, and water content on the volatile behaviors of lunar water ice. The findings of this study can provide technical and theoretical support for the in-situ exploration, extraction, and utilization of lunar water ice resources and offer insights into the existence and distribution of lunar water ice resources. • Apply the fractal theory of porous media on the research of icy lunar regolith volatilization. • Establish a volatilization model of water ice within icy lunar regolith. • Investigate the effect of temperature, relative density, and water content on volatilization. • Provide technical support for the exploration and extraction of lunar water ice resources. [ABSTRACT FROM AUTHOR]

Tool electrode wear varying with different materials in electrical discharge machining (EDM) is unavoidable, thus inevitably reducing the machining quality and accuracy of microstructures. To convert this disadvantageous phenomenon into a beneficial process, the paper proposed a wear-variation EDM (WV-EDM) approach to fabricate a laminated disc electrode (LDE) with stable-shape micro channels on the outer edge surface; this electrode was subsequently used to machine micro grooves on workpieces by EDM. The WV-EDM formation of the LDE, the relationship between relative volume wear rate of the disc foils and the machining depth, and flow field distribution in the machining gap of the LDE during processing were investigated. The results show that the method proposed herein could reliably produce LDEs with stable micro channels on the outer edge surfaces that could subsequently be employed to continuously machine micro groove arrays with the same machining depth on the same material workpiece by EDM, and especially LDE reshaping was unnecessary. Additionally, the "pump effect" of the vortex, located in the flow field between micro channels on the LDE and workpiece, was beneficial for debris removal. Using the proposed method, micro groove arrays and columnar microstructures were successfully fabricated on Ti–6Al–4V alloy workpieces. [ABSTRACT FROM AUTHOR]

A novel hot embossing process to fabricate the hierarchical macro/nano optical glass lens is innovatively proposed. [Display omitted] • A novel hot embossing strategy to fabricate the hierarchical macro/nano optical glass lens is innovatively proposed. • The hierarchical macro-/nano glass lens made by second hot embossing show good optical performance. • The deformation history and forming mechanism of hierarchical macro-/nano glass structures are revealed. Constructing nanostructured surfaces on the macro/micro-scale optical lens is of great importance in the improvement of light transmittance, reflection, and surface functionality of optical devices. In this paper, a flexible and novel material interface design and manufacturing method for hierarchical macro/nano optical glass lenses is proposed. To verify the feasibility of the presented manufacturing strategy, the deformation history and flow driving mechanism of multiscale structured surfaces during second hot embossing were studied by simulations and experiments. The results showed that solid-like glass preform exhibits a higher nanoscale deformation resistance and elastic recovery, which can reduce the distortion levels of the nanostructured surface. At small scales, molecular confinement greatly reduces the tectonic deformation of nanostructured surface at relatively low applied heat and pressure. However, beyond a specific thermal energy threshold, nanostructured convex surfaces are easily compressed into a smooth flattened surface. By collaborative control of embossing conditions, the nano-surface integrity of multiscale structured surface can be ensured during second hot embossing. Compared to the smooth macroscale optical lens, the hierarchical macro/nano glass lens exhibited better optical transmittance and antireflection properties. The proposed design and manufacturing strategy provides a facile and flexible solution for building the hierarchical macro/micro/nanostructure functional optics. [ABSTRACT FROM AUTHOR]

Glass hot embossing is a well-established and cost-effective manufacturing method for glass microstructures. However, the spatial volume affects deformation behaviors in closed mold cavities, which determines the final shape of the embossed glass. To investigate the spatial gas effect on the glass deformation mechanism during hot embossing, we used the focused ion beam (FIB) to fabricate blind micro-hole array structures with different depths as embossing templates. The experimental results demonstrated that the spatial volume of the mold cavity has a great influence on the energy of gas expansion, thus affecting the deformation height of glass microstructures during hot embossing. The deeper the cavity depth, the bigger the surface tension, resulting in larger surface concave deformation. Due to the surface tension of gas expansion, the deformation height of the edge zone is higher than that of the center zone at a higher embossing temperature until the heated glass is completely compressed into the mold cavity. Additionally, at lower embossing temperatures (520 °C), the heated glass has a large deformation resistance and elastic recovery. The more deformation volume escape from the shallower mold cavity because of the spatial effect, thus the deformation height decreases as the cavity depth reduces. The work provides a better understanding of manufacturing glass microstructures in hot embossing. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Superhydrophobic surfaces have a wide application prospect in the future industrial production due to its special abilities. The fabrication of superhydrophobic coating on metal surfaces can improve its performance. A one-step electrodeposition method is proposed to construct nanostructures on the surface of beryllium copper (Be-Cu) alloys, and a mixture of copper chloride and stearic acid is used as the electrolytes. The static contact angle of water on the surface can reach up to 163 ± 4°, a sliding angle of 1.7 ± 0.2°. The nanostructure and chemical composition on the surface were evaluated by scanning electron microscopy and X-ray photoelectron spectroscopy respectively. The corrosion resistance was tested through electrochemical measurement. It was found that the as-prepared superhydrophobic coating improved the corrosion resistance significantly. In addition, the coating with excellent self-cleaning performance was proved. This method solves the problems of complicated process, improves the efficiency effectively, and the electrolyte is eco-friendly. [ABSTRACT FROM AUTHOR]

Organic fuels are the main factors affecting the morphology, pore structure and catalytic active sites of metal oxides in solution combustion synthesis (SCS). However, due to the diversity of organic fuel structures, the specific role of organic fuel types on SCS is questionable. In this work, we compared the effects of five organic fuels on the thermocatalytic active sites of graded porous MgCo 2 O 4 nanomaterials. MgCo 2 O 4 (CA-MCO) prepared with citric acid as fuel has the largest specific surface area and the richest pore structure with the largest number of active sites. And the porous CA-MCO exhibited the best catalytic properties that the T HTD of AP decreased by 206.06 °C, the activation energy (E a) decreased by 104.58 kJ·mol−1, and the reaction rate (k) increased by 2.49 s−1. A possible catalytic mechanism for the thermal decomposition of AP was also proposed based on TG-MS and Hall effect tests. Finally, CA-MCO was applied to AP/HTPB-based composite solid propellants (CSPs), and the results showed that the introduction of CA-MCO significantly shortened the ignition delay time of the CSPs (From 29 ms to 8 ms), indicating its potential application in the CSPs. [Display omitted] [ABSTRACT FROM AUTHOR]

C f -ZrB 2 -SiC is a new composite material with excellent properties for making the next-generation aerospace component. This material is extremely difficult to removal by mechanical machining, and there is a lack of research on feasible secondary processing methods of this composite at present. Micro-EDM is not limited by material hardness, so it is very suitable for machining this material. In this paper, the Material removal mechanisms and processing characteristics of C f -ZrB 2 -SiC by micro-EDM is analyzed. The removal mechanism of composite materials is explored though the discharge crater morphology, and the single-discharge experiments of each phase materials with different medium and different energies are also carried out as a reference. Electrical discharge milling experiments of C f -ZrB 2 -SiC are performed to explore the medium on processing index, and found that the best surface quality and maximum processing efficiency can be realized in kerosene. An experiment with four factors (pulse width, voltage, peak current, capacitance) and three indexes (surface roughness, MRR, TWR) is designed to analyze the C f -ZrB 2 -SiC process characteristics of micro-EDM and the response surface diagram and second-order regression equation are obtained. Milling the C f -ZrB 2 -SiC by electrical discharge according to the optimal combination of surface roughness parameters deduced above, the as-machined surface is analyzed including the surface morphology by SEM, element content by EDS and the surface phase by XRD. The feasibility and advantages of micro-EDM on machining C f -ZrB 2 -SiC are prove. [ABSTRACT FROM AUTHOR]

Co 3 O 4 is an excellent catalyst for the thermal decomposition of ammonium perchlorate (AP) due to its spinel structure and more Co3+ as catalytically active sites. In this work, MCo 2 O 4 (M=Fe, Cu, Ni and Zn) with different Co species substituted with transition metal ion were prepared using triblock copolymer F127 as soft template by simple solvothermal and subsequent heat treatment. The porous MCo 2 O 4 samples have higher Co3+ / Co2+ ratio than Co 3 O 4 , and exhibits better catalytic performance for thermal decomposition of AP. Especially with the addition of FeCo 2 O 4 , the high decomposition temperature (HDT) of AP decreases by an amazing 196.25 °C, showing the most excellent catalytic performance. The activation energy (E a) decreases from 290.19 kJ·mol−1 for pure AP to 203.05 kJ·mol−1, while the reaction rate (k) increases from 0.499 s−1 to 1.699 s−1. Based on the electron transfer theory, the catalytic mechanism and active site of porous MCo 2 O 4 series cobaltate materials are discussed. The results show that the porous FeCo 2 O 4 not only has highest specific surface, but also has the highest Co3+/ Co2+ ratio, which suggest that the Co3+ on octahedral coordination sites is known as the catalytic active site for AP thermal decomposition. [Display omitted] • Ordered nanoporous MCo 2 O 4 (M=Fe, Cu, Ni and Zn) were successfully syntesized and substituted for the Co in Co 3 O 4. • The high Co3+ / Co2+ ratio and specific surface area of FeCo 2 O 4 provide higher catalytic activity and sites. • The kinetic parameters of AP thermal decomposition have been better optimized after adding porous FeCo 2 O 4. • The catalytic mechanism of porous FeCo 2 O 4 for thermal decomposition of AP is proposed. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a new method to fabricate tungsten microelectrode instantaneously by means of the pressure difference of plasma between cathode and anode in a single electrical discharge. The influence of main machining parameters, such as electrode material, polarity, dielectric medium, discharge duration and peak current, is analyzed by detailed experiments to obtain the fabricating law of tungsten microelectrode. The fabricating principle is described clearly. As the result of experiments, a tungsten microelectrode about 350μm in length and 30μm in diameter can be fabricated on the top of the tungsten wire of 0.125mm in diameter by this method. At the tip of the tungsten microelectrode, its radius is about 100nm. This method can greatly shorten the microelectrode fabrication time and effectively improve the reliability of the microelectrode. Especially, this method can fabricate a nanometer level tip in general electrical discharge machining (EDM) machine tool and need not add any other apparatus. The fabricated microelectrode can be used as a drilling tool in micro-EDM or a probe for scanner and measurement devices. [Copyright &y& Elsevier]

Micro-electro discharge milling (micro-ED-milling) with simply shaped electrode is highly regarded as a capable approach of machining 3D micro-structure because of its special machining mechanism and the variety of machinable materials. However, a specific CAD/CAM system is needed for generating tool path and related machining process. Due to nature of machining mode and tool electrode geometry, some vestige always remains on the machined surface during ED-milling of 3D structure especially on the complex surface which cannot be expressed with normal equations. To solve the problems of residual vestige, a slicing strategy for micro-ED-milling is proposed. The way of the tool path generation and the algorithm for smoother surface are studied systemically. Meanwhile, with the way of isoparametric interpolation, the machined freeform surfaces of lamination are significantly improved. As a result, some typical 3D structures are machined for verification, including an embossment of a human face within a circular area of 1 mm in diameter. [Copyright &y& Elsevier]

In micro scale metal forming processes, the plastic deformation behaviors are complicated and difficult to predict because of size effects. In this study, micro cylinder compression tests have been carried out to determine the plastic deformation behaviors in micro bulk metal forming. The effects of specimen height-to-diameter ratio and strain on the plastic deformation behaviors have been investigated extensively by compressing pure nickel micro cylinders. It is found that both the flow stress and friction coefficient decrease with the increase of the specimen height-to-diameter ratio. Friction coefficient decreases with the increase of compression ratio for specimens with the same height or decreases with the increase of the specimen height-to-diameter ratio under the same compression ratio. A relationship between normal pressure of lubricant friction, strain and height-to-diameter ratio ( H/D ) is established. A modified friction model is proposed based on the assumption of open-close lubricant pockets by introducing the specimen geometrical parameters. The calculated friction coefficients by the developed model and their tendencies are in good accordance with the experimental ones. It is also found that the ratio of the real contact areas (RCAs) decreases with increase of the specimen height-to-diameter ratio under the same compression ratio which can explain the decrease of the equivalent friction stress between the tool and the specimen. The new developed friction model enables more flexible modeling of friction behaviors in microforming processes. [ABSTRACT FROM AUTHOR]

Micro wire electrical discharge machining (micro-WEDM) provides a promising alternative for micro gear machining. However, the processing defect of non-intact tooth profile often appears due to the influence of micro gear gravity, flushing force and explosive force in micro-WEDM process. This paper presents a process change of micro-WEDM to achieve the precise fabrication of micro gear with intact tooth profile, i.e. firstly reserving a sharp corner on the gear teeth where the processing defect exists and then removing it by the second processing of micro-WEDM. The locating and clamping of the micro gear with sharp corner has been achieved using a novel self-centering flexible fixture. The machining error during the second processing is analyzed, and whilst the process datum is accurately determined. Appropriate processing parameters are obtained by performing preliminary experiments on X153CrMoV12 workpiece, indicating that high open voltage and discharge capacitance cause large kerf width, moderate reference voltage and feed rate lead to narrow kerf width. The static contact between the core jig of the fixture and the micro gear with sharp corner is theoretically analyzed using ABAQUS software and experimentally proved to be in good condition. To verify the feasibility and repeatability of the proposed approach, five micro gears with 10 gear number, 0.1 mm module and 2 mm tooth width are machined using 50 μm diameter wire electrode, exhibiting excellent conformity, machining error with less than 1.5 μm and surface roughness Ra with 0.9 μm. [ABSTRACT FROM AUTHOR]

With the challenges of arid transboundary river water management among Central Asian countries, it is important to evaluate the water stress and propose practicable climate adaptation strategies. This study used the Syr Darya Basin (SDB) in a Central Asia data scarce region as the study area and, conducted the first quantified analysis of the spatiotemporal characteristics of water supply and requirements at the basin and irrigation district scale; identified its driving mechanisms based on systematic monitoring data concerning reservoir regulation and complex crop structure from 2000 to 2018; and a climate change scenario combined with a crop restructuring scenario was applied to evaluate water conservation effects and propose a climate adaptation strategy from 2019 to 2030. The results showed that runoff increased by 7.45 billion m3 but the water withdrawal decreased by 3.42 billion m3 after reservoir regulation in the basin during 2000–2018. Due to the unified water allocation, it was challenging to conduct and usually exceeded the plan by 0.4–8.5 %. The total crop water requirement (TCWR) mainly derived from cotton (61.5 %), winter wheat (12.1 %) and rice (13.9 %) increased by 3.15 billion m3 (+30.7 %) and the influence of crop area (380 million m3/a) was greater than that of climate (130 million m3/a). The wind speed (27.5 %) and rice area (19.2 %) also significantly contributed to the TCWR variation. The contradiction between water supply and requirement resulted in water scarcity in the basin. From 2019–2030, the water conservation effect of winter wheat (+20 %) under the restructuring scenarios reached 28.7 mm, which helped relieve water stress under the scenario of a 0.51–0.91 °C increase. Thus, priority planting of a winter wheat rotation and low water consuming crops is a practicable approach for coping with water scarcity and adapting to climate change in arid transboundary rivers of Centra Asia. [Display omitted] • A crop restructuring scenario was proposed to adapt to future climate change. • Increasing wind speed and rice area contributed the most to the water stress. • Priority development of winter wheat rotation is practical for water conservation. [ABSTRACT FROM AUTHOR]

Mandarin vole ( Lasiopodomys mandarinus ) is a subterranean rodent that is often used as a model for studying subterranean hypoxic stress in mammals. However the taxonomy of this species is still in dispute. Mitochondrial DNA (mtDNA) has long been used for phylogenetic reconstruction and, in this study, the complete mitochondrial genome of L. mandarinus mandarinus was sequenced. Our results showed that the mitochondrial genome of L. m. mandarinus is a circular molecule of 16,367 bp, which contains 13 protein-coding genes, 22 tRNA and 2 rRNA genes. Except for the 8 tRNA and ND6 genes, all other mitochondrial genes are encoded on the heavy strand. We also analyzed the phylogenetic position of L. mandarinus in respect to the tribe Arvicolini using the sequence of complete Cytb gene, 2rRNA genes and 12 protein-coding genes, and maximum likelihood and Bayesian methods. Our results gave further support to the species status of L. mandarinus and the generic status of Lasiopodomys . [ABSTRACT FROM AUTHOR]

Evapotranspiration and soil moisture content (SMC) are key elements of the hydrological cycle. Accurate prediction of the dynamic processes of evapotranspiration and soil water is essential for irrigation and water management. Here, the boosted regression tree (BRT) method was employed to quantify environmental controls on actual evapotranspiration (ET a), potential evapotranspiration (ET 0), and SMC using monitoring data from the Wudaogou hydrological experimental station. The results indicated that: (1) the BRT algorithm was effective in predicting the relative control of different environmental factors on ET a , ET 0 , and SMC; and (2) vapor pressure deficit (VPD) was the most important factor affecting daily ET 0 , and sunshine duration (SSD) also played a nonnegligible role. The results further explained the phenomenon of the "evaporation paradox" in the study area. SSD could be a leading control on daily ET a , followed by VPD, leaf area index (LAI). (3) Among the underground factors, groundwater level (GL) and LAI played a dominant role in the relative contribution to SMC. Among the aboveground factors, relative humidity (RH) and soil temperature (TS) have a relatively large influence on SMC. (4) The differences in SMC at different depths were determined by multiple influencing factors, including LAI, VPD, and precipitation (P). This study also underscores the importance of vegetation variations to hydrological cycle processes. In general, climate warming and an increase in extreme rainfall events will increase the control of temperature on SMC and weaken the control of P on SMC in the future. • A boosted regression tree method is used to quantify controls on ET a and SMC by environmental factors. • The impact of SSD on ET a is substantial in the study sites, and the impact of VPD and LAI on ET a could not be ignored. • GL and LAI significantly affect the variation of SMC in the study sites. • SMC differences at different depths were determined by a combination of influencing factors. [ABSTRACT FROM AUTHOR]

Abstract: In micro-wire electrical discharge machining (micro-WEDM), the machined kerf width varies with different machining parameters, which greatly influences the machining precision. In order to study the kerf variations in micro-WEDM, the mathematical model of wire lateral vibration in machining process is established and its analytical solution is obtained in this paper. The model is practically verified on a self-developed micro-WEDM machine. Under this model, a 30.8μm width slot is achieved on a stainless steel workpiece with ∅30μm wire-tool. [Copyright &y& Elsevier]

The acoustic softening effect in metals during plastic deformation has been widely investigated in the past decades. However, the mechanism of such an acoustic plasticity remains controversial. As a result, several models were proposed to understand the acoustic softening effect in terms of stress superposition, thermal activation theory, crystal plastic theory and other mechanisms associated with dislocation evolution. In this study, we proposed a mechanism that the athermal dislocation dynamics may heterogeneously change at microstructure level during ultrasonic vibration assisted (UVA) deformation. Specifically, the work required to eject dislocations from grain boundaries may be altered by the acoustic energy absorption difference of a dislocation in the grain interior and one in the grain boundary. As a result, the acoustic softening effect on the Hall-Petch behavior was modeled by incorporating a power function of acoustic energy density into the dislocation ejection work. To validate the developed model, UVA micro-tension tests were conducted on pure titanium specimens. Results showed that the Hall-Petch slope decreased due to ultrasonic vibration, and the ultrasound-induced decrease of the Hall-Petch slope increased with plastic deformation. Note that our model predictions matched well with the experimental results at the lower strains, providing an alternative insight into the acoustic softening effect on the Hall-Petch behavior. Microstructure examinations showed that the superimposed ultrasonic vibration in micro-tension could lead to the retardation of texture evolution, the decreases in kernel average misorientation (KAM) value, low-angle grain boundary (LAGB) fraction and dislocation density in titanium foils, which somewhat supported our model assumptions in terms of the acoustic energy dependent reduction in dislocation density and the enhanced dislocation ejection causing the improvement of plastic compatibility. • A Hall-Petch model based on a dislocation ejection mechanism was developed with the acoustic plasticity involved. • Ultrasonic vibration induced the decease of the Hall-Petch slope which increased with plastic deformation. • The proposed model can capture the decrease in strain hardening rate in UVA micro-tension of titanium. • The model predictions matched well with the acoustic softening effect on the Hall-Petch slope at lower strains. • Microstructure examinations showed dislocation density reduction and enhanced plastic compatibility in UVA foils. [ABSTRACT FROM AUTHOR]

This work puts forward numerical and experimental investigations on laser dicing of glass-anisotropic single-crystal silicon double-layer wafer using laser induced thermal-crack propagation (LITP). A semiconductor continuous wave laser working at the defocusing mode serves as volumetric heat source for glass layer while as surface heat source for silicon layer. Based on the classical fracture theory, a static seam-type crack is introduced under the circumstance of ABAQUS to simulate the crack fracture modes in glass layer as well as silicon layer with crystal planes of (100), (110) and (111) during laser dicing in different dicing directions. In the experiments, processing parameters are kept the same as the simulations and typical dicing directions obtained from simulations are also used. The surface morphologies of crack edges are measured by the optical microscope and surface profiler. Through the comparison of numerical and experimental results it is discovered that for the specific substrate, the evolution of crack edge qualities in different dicing directions and different layers can be interpreted based on the corresponding stress distribution and stress intensity factor (SIF) ratio explicitly. And most important of all, the anisotropy of silicon layer has significant influence on the fracture mode and edge quality of crack in both layers. [ABSTRACT FROM AUTHOR]