ZnO纳米墙的电化学沉积法制备及紫外探测性能分析

以硝酸锌水溶液作为电沉积液,采用电化学沉积法制备了氧化锌(ZnO)纳米墙,研究了沉积电压对其表面形貌、晶体结构、拉曼光谱、光致发光谱、透过率以及紫外探测性能的影响。实验结果表明,该方法制备的ZnO纳米墙的均匀性较好,具有纤锌矿结构,沿(002)晶面择优生长,有较明显的E_2(high)模峰,在394 nm处有较强烈的紫外激发峰。紫外探测实验表明:在紫外光照射下,ZnO纳米墙的光电流迅速达到饱和,当沉积电压为1.6 V时,ZnO纳米墙的光电流值最大,对应的响应时间和恢复时间分别为1.36 s和2.23 s;当测试偏压为5 V时,光暗电流比为38.96,光电响应度为0.611 A/W。     

First-principles study of the effects of selected interstitial atoms on the generalized stacking fault energies,strength, and ductility of Ni

We analyze the influences of interstitial atoms on the generalized stacking fault energy （GSFE）, strength, and ductility of Ni by first-principles calculations. Surface energies and GSFE curves are calculated for the （112） （111） and / 101） （ 1 1 1） systems. Because of the anisotropy of the single crystal, the addition of interstitials tends to promote the strength of Ni by slipping along the （10T） direction while facilitating plastic deformation by slipping along the （115） direction. There is a different impact on the mechanical behavior of Ni when the interstitials are located in the slip plane. The evaluation of the Rice criterion reveals that the addition of the interstitials H and O increases the brittleness in Ni and promotes the probability of cleavage fracture, while the addition of S and N tends to increase the ductility. Besides, P, H, and S have a negligible effect on the deformation tendency in Ni, while the tendency of partial dislocation is more prominent with the addition of N and O. The addition of interstitial atoms tends to increase the high-energy barrier γmax, thereby the second partial resulting from the dislocation tends to reside and move on to the next layer.     

地下坑道对其临界震塌爆距处钻地武器爆炸载荷的动力响应

利用非线性显式动力有限元程序,采用多物质流固耦合计算方法,就GBU-28钻地弹在地下坑道临界震塌爆距处爆炸时,对地下直墙拱坑道的动力响应进行数值模拟。根据围岩动力稳定性和混凝土动态强度判据,结合模拟结果,分析衬砌结构与围岩的相互作用。钻地弹在直墙圆拱断面的坑道临界震塌爆距处爆炸时:围岩处于临界破坏状态,但混凝土衬砌结构处于稳定状态;拱顶的应力峰值明显,且柱状装药情况下,爆炸近区的应力较集团装药情况下的大;拱肩位置出现应力集中;围岩与衬砌结构特征位置处的相互作用载荷与对应质点的振动速度相互耦合,基本成对应的关系。     

爱“臭美”的波斯猫

正波斯猫特别爱美,心灵手巧的她喜欢把家里布置(zh)ì得漂漂亮亮的。最近,波斯猫又想出一个布置家居的新花样:用五颜六色的彩纸剪出12个大大小小的圆片,然后,用图钉把这些圆片钉在墙上,这样白色的墙就会变得很漂亮。说干就干,波斯猫忙活了好半天,终于把圆片钉到了墙上。波斯猫心花怒放地欣(xīn)赏(shǎnɡ)着自己的"杰作",突     

基于Theil指数的复合土钉墙安全灰色评价

针对复合土钉墙的安全评价问题,以复合土钉墙基坑支护技术规范为依据构建了安全评价指标体系,并在运用Theil指数确定安全评价指标权重的基础上,对复合土钉墙安全进行灰色综合评价,得出安全评价等级.为复合土钉墙安全评价提供了新思路.     

Scalar mesons and glueballs in Dp-Dq hard-wall models

We investigate the light scalar mesons and glueballs in the Dp-Dq hard-wall models, including D3-Dq, D4-Dq, and D6-Dq systems. It is found that only in the D4-D6 and D4-Ds hard-wall models are the predicted masses of the clq scalar meson fo scalar glueball consistent with their experimental or lattice results. This indicates that D4-D6 and D4-Ds hard-wall models are the favorite candidates of the realistic holographic QCD model.     

Characteristics of the sampling paddle modules of neutron wall from the cosmic ray test

In the construction of a large area neutron detector （neutron wall） that is used to detect neutrons at GeV energies, the performances of all the sampling paddle modules prepared for the neutron wall are investigated with a specially designed test bench. Tested by cosmic rays, an average intrinsic time resolution of 222.5 ps is achieved at the center of the modules. The light attenuation length and the effective speed of the light in the module are also investigated.     

Electron Acceleration in the Bubble Regime with Dense-Plasma Wall Driven by an Ultraintense Laser Pulse

An optimizing scheme for electron acceleration in the wake bubble with dense-plasma wall driven by an ultraintense laser pulse is presented and investigated by particle-in-cell simulation. The wall has an inner diameter matching the expected lateral bubble size. The bubble shape can be transversely controlled and longitudinally shrunk. The accelerated electrons as a bunch have a high quality because the electrons almost stay close to the bottom of the bubble and are accelerated to much high energy with narrow energy spread.     

MEASUREMENT OF ADHESION FORCES IN AIR WITH THE VIBRATION METHOD

The vibration method represents a practical method for the measurement of adhesion forces and adhesion force distributions. This method causes sinusoidally alternating stresses and yields detachment and contact forces between particles and substrate of the same order of magnitude. Alternating contact forces of the vibration method can cause an adhesion force intensification through flattening of asperities. The measuring principle of the vibration method and the analysis of experimental results are described in the article. Normal adhesion forces (pull-off forces) are measured using the vibration method and the colloidal probe technique. The results of both methods show good agreement for small particle sizes. The influence of the detachment force direction is shown by comparing tangential and normal adhesion forces measured using particle reentrainment in a turbulent air flow and the vibration method, respectively. The surface roughness of the substrate and the relative humidity are shown to significantly influence the measured adhesion forces. For the calculation of the adhesion forces, an approach by Rabinovich was combined with approximations of plastic micro asperity flattening. The Rabinovich approach accounts for roughness effects on the van der Waals force by incorporating the rms roughness of the interacting surfaces, rms-values of the particles and substrates were measured with atomic force microscopy at different scanning areas.     

底部两层框架-抗震墙砌体房屋的动力计算模型及侧向刚度控制

底部两层框架—抗震墙上部多层砌体房屋,属于混凝土—砌体混合结构的范畴。这种建筑适应城市建设发展的要求,且较纯框架结构经济,特别受到房屋开发商的青睐,在相对落后和不发达地区尤为适用。为了研究这类结构在地震区的适用性,作者在现有试验研究的基础上,分析了底部两层框架—抗震墙砌体房屋在水平地震作用下的力学性能,给出了这种结构的动力计算模型和特征点参数的取值方法,并编制了结构从受荷到破坏的全过程弹塑性分析程序。同时,结合工程实例,计算了六种不同侧向刚度比条件下结构的弹塑性动力反应。根据计算结果的分析,认为新颁布的《建筑抗震设计规范》(GB50011)对于砌体过渡层与第二层框剪层的侧向刚度比限值偏小,并提出了合宜的刚度比取值范围,可供设计人员在抗震设计时参考和借鉴。