摘要：The direct hydrogenation of CO2 using H2 gas is a one-stone-two-birds route to produce highly valueadded hydrocarbon compounds and to lower the CO2 level in the ***,the transformation of CO2 and H2 into hydrocarbons has always been a great challenge while ensuring both the activity and selectivity over abundant-element-based *** this work,we designed a Schottky heterojunction composed of electron-rich MoC nanoparticles embedded inside an optimized nitrogen-doped carbon support(MoC@NC)as the first example of noble-metal-free heterogeneous catalysts to boost the activity of and specific selectivity for CO2 hydrogenation to formic acid(FA)in liquid phase under mild conditions(2 MPa pressure and 70℃).The MoC@NC catalyst with a high turnover frequency(TOF)of 8.20 molFA molMoC^-1 h^-1 at 140℃ and an excellent reusability are more favorable for real applications.

摘要：高通量表征技术在金属材料分析领域具有重要应用价值,它能够实现对金属材料进行跨尺度的全域分析,评价材料表面宏观特性、微观不均匀性及局部缺陷。辉光放电溅射可沿样品表面的纵深方向,以大尺寸、平坦且快速的方式逐层剥蚀样品,再将暴露出真实显微组织的样品送至多种分析仪器中进行成分、性能、组织结构的分析,从而作为金属材料的高通量表征样品前处理环节的关键设备。在传统Grimm型辉光溅射源的基础上,本研究搭建了一种专为高通量实验设计的辉光放电溅射系统,该系统将辉光溅射尺度由mm级扩展至cm级,同时实验发现了大尺寸溅射会导致辉光放电强度及溅射速率降低这一现象。针对这一现象,结合通过COMSOL Multiphysics仿真计算的辉光放电电子运动轨迹、电子密度以及化学反应速率等结果,该研究提出了一种通过施加扫描磁场来增强辉光放电光谱(GD-OES)强度以及溅射速率的方法。实验选用T2紫铜样品来探究扫描磁场的增强效果,结果表明,应用扫描磁场增强装置可获得更强的光谱信号强度及更快的溅射速率。在保持放电电压和电流不变的前提下,Mo、Cu元素的光谱强度分别增至无磁场时的1.43~11.97倍和1.13~26.50倍。其中,Mo元素光谱强度最大值可达53421 Cts,Cu元素光谱强度最大值可达76948 Cts,分别是无磁场时的6.86倍、4.32倍。此外,该方法可以显著地提高溅射速率,当阳极筒孔径为?15 mm时,T2紫铜样品的溅射速率提高了4.35倍,最高可达2662.09 nm·min^(-1)。使用白光干涉仪和金相显微镜对溅射坑表面的平整度和显微组织图像进行了采集,结果显示磁场引入对溅射坑表面粗糙度未产生显著影响,同时能清晰地呈现样品的真实显微组织特征。综上,实验结果证实,应用扫描磁场增强装置可在确保溅射平整度不受影响的前提下,实现光谱信号强度和溅射速率的提升,为解决大尺寸溅射引起的低溅射速率问题提供了新方法。

摘要：目的 设计重测信度高的小鼠颈肌前庭诱发肌源性电位(cVEMP)实验方法以验证定位胸锁乳突肌的准确性。方法 选用2月龄ICR雄性小鼠3只,1只解剖定位小鼠胸锁乳突肌,其余2只设计实验方案验证定位准确性。结果 记录电极定位到小鼠胸锁乳突肌上可重复引出清晰的cVEMP波形。结论 根据2只实验小鼠均可测得重测信度高的cVEMP波形,提示本研究定位胸锁乳突肌位置准确。

摘要：分析长江口河势和潮滩冲淤发展变化 ,针对不同潮滩的冲淤稳定性 ,提出在冲刷河段因不同破坏因素而采用不同的保滩护岸方案 ,防止水土流失 ,稳固河势发展。从长江口非工程措施和工程措施 (围垦、保滩 )对长江口资源、环境和生态的正面和负面影响分析 ,提出保滩护岸。

摘要：Most materials can be easily corroded or ineffective in carbonaceous atmospheres at high temperatures in the reactor core of the high temperature gas-cooled reactor(HTGR).To solve the problem,a material performance test apparatus was built to provide reliable materials and technical support for relevant experiments of the *** apparatus uses a center high-purity graphite heater and surrounding thermal insulating layers made of carbon fiber felt to form a strong carbon reducing atmosphere inside the *** designed tungsten rhenium thermocouples which can endure high temperatures in carbonaceous atmospheres are used to control the temperature field.A typical experimental process was analyzed in the paper,which lasted 76 hours including seven *** results showed the test apparatus could completely simulate the carbon reduction atmosphere and high temperature environment the same as that confronted in the real reactor and the performance of screened materials had been successfully tested and *** temperature in the apparatus could be elevated up to 1600oC,which covered the whole temperature range of the normal operation and accident condition of HTGR and could fully meet the test requirements of materials used in the reactor.

摘要：为探究动载作用下天然板岩的断裂韧度,论文采用板岩制作直切槽半圆盘弯曲试样(NSCB),利用直径50 mm分离式霍普金森压杆(SHPB)试验系统进行了动态冲击试验,同时使用高速摄像机记录了其裂纹扩展过程,研究了不同冲击气压和预制裂纹长度下板岩的动态断裂韧度及裂纹扩展速度。结果表明:试件的动态断裂韧度与冲击气压和加载率呈现正相关,而随着预制裂纹长度的增加动态断裂韧度先增加后减小,根据拟合结果,当预制裂纹长度为7.45 mm时试件的动态断裂韧度达到最大值,0.2、0.3和0.4 MPa三种冲击气压下对应的动态断裂韧度最大值分别为2.99、3.57和4.14 GPa·m^(1/2);试件的破坏过程可以分为动态损伤、裂纹孕育、裂纹形成、裂纹扩展和试件断裂五个阶段;试件主裂纹的扩展速度波动较大,而预制裂纹长度对试件裂纹扩展速度的影响较小。研究揭示了不同工况下板岩试件动态断裂行为的差异,对该类岩性地下工程支护、爆破参数设计具有一定的参考意义。

摘要：目的探讨内镜下经下颌角-颈静脉孔区手术入路的解剖学基础。方法收集湿性尸头标本5具,模拟内镜下经下颌角-颈静脉孔区手术入路对湿性尸头标本进行解剖,观察相关解剖结构,测量手术操作深度和角度。结果该手术入路形成了带蒂下颌角骨瓣,骨瓣长为(23.74±0.95)mm,宽为(18.95±0.56)mm。移位下颌角骨瓣后手术操作深度为(8.54±0.55)mm,复位下颌角骨瓣后手术操作深度为(24.94±0.90)mm,差异有统计学意义(P<0.05);移位下颌角骨瓣后手术操作角度为(69.60±3.30)°,复位下颌角骨瓣后手术操作角度为(26.20±2.20)°,差异有统计学意义(P<0.05)。结论内镜下经下颌角-颈静脉孔区手术入路形成带蒂下颌角骨瓣,可以增加手术操作角度、缩短操作深度,提高手术自由度,该手术入路值得进一步研究和在临床实践中探讨。

摘要：局域共振带隙和Bragg带隙可同时存在于超材料梁中,利用两种带隙之间的相互耦合效应可以实现超宽耦合带隙设计,在宽带减振领域极具应用潜力.以往研究通常考虑单振子超材料梁的单阶耦合带隙设计,因而只能实现单阶的超宽耦合带隙,无法满足双目标或多目标频带的宽带减振需求.为此,本文开展了双振子超材料梁的双阶耦合带隙调控设计研究,提出了一种实现双阶耦合宽带隙的设计方法,分析了所设计双阶耦合带隙相比传统单阶耦合带隙的带宽优势,并探究了双振子质量分配比对双阶耦合带隙总宽度的影响,进一步设计出最优的质量分配比,使得实现的双阶耦合带隙的总宽度最宽.此外,还采用谱元法研究了基于双阶耦合带隙设计的双振子超材料梁的减振特性,通过与有限元法进行对比,验证了谱元法的准确性,研究表明基于双阶耦合带隙设计可以实现两个宽频带范围的高效减振.

摘要：In order to simultaneously improve strength and formability,an analytical model for the concentration distribution of precipitates and solute elements is established and used to theoretically design and control the heterogeneous microstructure of Al−Zn−Mg−Cu *** results show that the dissolution of precipitates is mainly affected by particle size and heat treatment temperature,the heterogeneous distribution level of solute elements diffused in the alloy matrix mainly depends on the grain size,while the heat treatment temperature only has an obvious effect on the concentration distribution in the larger grains,and the experimental results of Al−Zn−Mg−Cu alloy are in good agreement with the theoretical model predictions of precipitates and solute element concentration *** the concentration distribution of precipitates and solute elements in Al−Zn−Mg−Cu alloys is the premise of accurately constructing heterogeneous microstructure in micro-domains,which can be used to significantly improve the formability of Al−Zn−Mg−Cu alloys with a heterostructure.

摘要：First-principles calculations were performed to investigate the structures and energetics of {101n} coherent twin boundaries(CTBs) and glide twin boundaries(GTBs) in hexagonal close-packed(hcp) Ti. The formation mechanism of GTBs and their correlation with twin growth were fundamentally explored. Results suggested that GTBs can form from the gliding of CTBs, through their interaction with basal stacking fault. The gliding eventually restored the CTB structures by forming a pair of single-layer twinning disconnections. The pile-up of twinning disconnections should be responsible for the wide steps at twin boundaries as observed in high-resolution transmission electron microscopy, which can further promote twin growth. Possible effects of various alloying elements on pinning twin boundaries were also evaluated, to guide the strengthening design of Ti alloys.