摘要：Molybdenum-based catalysts have demonstrated significant potential in the electrocatalytic hydrogen evolution reaction(HER).However,the limited exposure of active sites and strong hydrogen adsorption result in suboptimal ***,a Mo_(2)N±MoSe_(2) heterojunction is prepared on carbon cloth(MNS/CC)to enhance the *** strong electronic interaction between Mo_(2)N and MoSe_(2),combined with the lower work function of Mo_(2)N,creates an intrinsic electric field at the heterojunction interface,which markedly improves charge transfer ***,the optimized electronic structure of Mo sites further enhances charge transfer and intrinsically catalytic activity in *** a result,MNS/CC requires overpotentials of mere 65 and 210 mV to achieve current densities of 20 mA cm^(−2) and 1 A cm^(−2),respectively,with a Tafel slope of only 96 mV dec−***,MNS/CC maintains stable operation at 1 A cm^(−2) for 240 h without significant *** results offer insights into the design of non-precious metal-based electrocatalysts for industrial hydrogen production.

摘要：During oil-gas well drilling and completion, downhole tools and apparatus should be conveyed to the destination to complete a series of downhole works. Downhole tractors have been used to convey tools in complex wellbores, however a very large tractive force is needed to carry more downhole tools to accomplish works with high efficiency. A novel serial active helical drive downhole tractor which has significantly improved performance compared with previous work is proposed. All previously reported helical drive downhole tractors need stators to balance the torque generated by the rotator. By contrast, the proposed serial downhole tractor does not need a stator; several rotator-driven units should only be connected to one another to achieve a tractive force multifold higher than that was previously reported. As a result, the length of a single unit is shortened, and the motion flexibility of the downhole tractor is increased. The major performance indicators, namely, gear ratio, velocity, and tractive force, are analyzed. Experimental results show that the maximum tractive force of a single-unit prototype with a length of 900 mm is 165.3 kg or 1620 N. The analysis and experimental results show that the proposed design has considerable potential for downhole works.

摘要：Engineered cementitious composite(ECC)is a class of high performance cementitious composites with pseudo strain-hardening behavior and excellent crack control *** of concrete with ECC can largely reduce the cracking and durability problems associated with brittleness of *** this paper,a simplified constitutive model of the ECC material was applied to simulate the flexural behaviors of the steel reinforced ECC and ECC/concrete composite beams with finite element *** simulation results are found to be in good agreement with test results,indicating that the finite element model is reasonably accurate in simulating the flexural behaviors of the steel reinforced ECC flexural *** effects of the ECC modulus,ECC tensile ductility,ECC thickness and ECC position on flexural behaviors in terms of ultimate moment,deflection and the maximum crack width of the steel reinforced ECC or ECC/concrete composite beam are hence evaluated.

摘要：Scratch is a visual programming tools that is widely used in many lessons. While many of the lessons use thecoding features of Scratch, teachers may also use the interactive features in their lessons. In a course for in-serviceprimary school teachers, on the use of technology for the school-based learning and teaching, teachers had anexperience on how Scratch can be used to facilitate learning. Starting from no programming history, teachers spent3 hours each on 4 topics including Take-Away Model, The Four Operations, Divisibilities, and Area of SimpleFigures, via step-by-step procedures on setting up animations within the theme that would attract students, and withthe interaction responses such as text and sound, they successfully handled the use of Scratch and could design andmake their lessons perfectly to their students. While teachers suggest learning should be extended to the second andthe third classroom, with this easy-to-learn programming language, teachers could now facilitate learning ofstudents by the attractive school-based games, which focus on particular topics the teachers had selected.

摘要：Bromination is used as a strategy to improve biological activity in medicinal *** order to study on the structure-activity relationships of the novel acetylcholinesterase inhibitors with 7H-thiazolo[3,2-b]-1,2,4-triazin-7-one scaffold,based on our previous work and molecular modeling,a series of novel 3-aryl-6-（bromoarylrnethyl）-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives were designed by molecular docking,synthesized and characterized by mass spectra,infrared spectra,proton NMR and elemental *** study of AChE inhibitory activity was carried out using the Ellman colorimetric assay with huperzine-A as the positive *** of all target compounds exhibited more than 45%inhibition at 10μmol/*** preliminary structureactivity relationship was the bromine atoms and the hydroxyl group at the phenyl ring at the C6 position of the parent nucleus played significant roles in the AChE inhibitory activity of the target compounds.

摘要：In this paper, four point bending tests were carried out to investigate the flexural properties of PVA fiber reinforced engineered cementitious composites (ECC) with different mix proportions. Based on the test results, the flexural toughness was evaluated with the methods of JSCE and post crack strength method (PCSm), respectively. Several parameters such as amount of water reducer, amount of sand, and fiber volume fraction were investigated to study their effects on the flexural toughness of ECC beams. According to the test results, superfluous water reducing additions can cause adverse effect on strength of the matrix and interfacial bond between fibers and the matrix, resulting in decreased bending strength and flexural toughness of ECC beams. Increase of the fiber volume fraction can result in increased flexural strength and toughness due to enhanced bridging effect between fibers and cementitious matrix. High amount of sand can reduce ductility and strain hardening behavior of ECC material, and better flexural toughness can be achieved when the amount of sand by weight is set to 0.2 for current water/cement ratio.

摘要：The rational design and construction of novel two-dimensional(2D)carbon nitrides(CNs)beyond g-C_(3)N_(4) is a hot topic in the fields of chemistry and *** by the polymerisation of urea,we have prepared a series of novel C-C bridged heptazine CNs UO_(x)(where x is the ratio of urea to oxamide,x=1,1.5,2,2.5,and 3),which are similar to(C_(6)N_(7))n,upon the introduction of *** predicted using density functional theory(DFT)calculations,the conjugated structure of UO_(x) was effectively extended from an individual heptazine to the entire ***,its bandgap was reduced to 2.05 eV,and its absorption band edge was significantly extended to 600 ***,its carrier transfer and separation were significantly enhanced,establishing its superior photocatalytic *** optimised UO_(2) exhibits a superior photocatalytic hydrogen production rate about 108.59 lmol h^(-1)(using 10 mg of catalyst)with an apparent quantum efficiency(AQE)of 36.12%and 0.33%at 420 and 600 nm,respectively,which is one of the most active novel CNs reported to ***,UO_(2) exhibits excellent photocatalytic activity toward the oxidation of diphenylhydrazine to azobenzene with conversion and selectivity reaching~100%,which represents a promising highly efficient 2D CN *** phenols degradation,UO_(2) also displayed significantly higher activity and durability during the degradation of phenol when compared to traditional g-C_(3)N_(4),highlighting its significant potential for application in energy,environment and photocatalytic organic reactions.

摘要：Bismuth‐based photocatalysts are a class of excellent visible‐light photocatalysts;however,their redox activity is relatively poor and the efficiency of photogenerated carrier separation is low,limiting their development and application in the field of *** address these issues,a series of polyoxometalate PW_(12)O_(40)^(3–)‐doped Bi_(2)O_(3–x)/Bi Schottky photocatalysts PW_(12)@Bi_(2)O_(3–x)/Bi‐n(PBOB‐n,where n is the amount of NaBH4,i.e.,6,12,18,24,and 48 mg)were prepared by a simple electrospinning/calcination/in‐situ NaBH4 reduction *** this composite photocatalyst,the doping of PW_(12) could effectively adjust the electronic structure of Bi_(2)O_(3–x) and improve its redox *** a shallow electron trap,PW_(12) promoted the separation of the photogenerated ***,desirable Schottky junction between the metal Bi nanoparticles and PW_(12)@Bi_(2)O_(3–x) further accelerated the separation of the photogenerated *** synergistic effect of the aforementioned factors endowed PBOB‐n with excellent photocatalytic *** the samples,PBOB‐18 exhibited superior photocatalytic *** visible‐light irradiation,93.7%(20 mg catalyst)of 20 ppm tetrabromobisphenol A(TBBPA,20 mL)was degraded in 60 *** activity was 4.4 times higher than that of Bi_(2)O_(3).PBOB‐18 also exhibited an ultrahigh photocatalytic performance for the removal of *** removal rate(600 ppb)reached 83.3%in 30 min,making it one of the most active Bi‐based ***,the photocatalytic mechanisms of PBOB‐18 for TBBPA and NO have been *** work provides a new direction and reference for the design of low‐cost,efficient,stable,and versatile photocatalysts.

摘要：Many higher education institutions around the world have established quality control systems to maintain standards. This study reports on the issue of comparing English language curricula by means of an institutional review in a northeast province in China in 2012. The study was essentially a qualitative inquiry with data collected online through documents submitted by the institutions and through semi-structured follow-up interviews. Thirty-seven participants from 12 institutions participated in the study. Research findings indicated that curriculum orientations varied across institutions and were reflected in their curriculum designs. Such a modus operandi, it is anticipated, may shed useful light on the understanding of curriculum reform currently being conducted in China in light of the rising demand for, and the needs of, internationalized and localized curricula, as well as providing an understanding of curricula at various institutions.

摘要：In this study, a membraneless, monolithic micro photocatalytic fuel cell with an air-breathing cathode was developed for simultaneous wastewater treatment and electricity generation. In this newly-developed micro photocatalytic fuel cell, the photoanode and cathode were arranged with a shoulder-to-shoulder design, forming two planar electrodes. Such design offers several advantages of enhanced mass transfer, uniform light distribution, short light transfer path, membrane elimination and easy fabrication, integration, and compatibility with other microdevices. The performance of this type fuel cell was evaluated by using methanol as a model pollutant under the alkaline condition. Experimental results indicated the developed micro photocatalytic fuel cell was able to show good photo-response to the illumination and satisfactory performance as well as durability. Parametric study on the cell performance was also performed. It was found that increasing the light intensity, methanol concentration andKOH concentration could improve the cell performance. But for the effect of the liquid flow rate, it was shown that the cell performance firstly increased with increasing the liquid flow rate and then decreased with further increasing the liquid flow rate. This study not only opens a new avenue for the design of the micro photocatalytic fuel cell but also is helpful for the optimization of the operating conditions.