三维无机一有机杂化微孔化合物[Zn3（BTC）2（H2O）3]n的合成与结构

传统的沸石和分子筛微孔晶体材料是指以硅酸盐、硅铝酸盐、磷铝酸盐和无机金属磷酸盐为骨架的晶体材料。     

平面上n个点的集合的一个性质

平面上ｎ个点的集合的一个性质歌今这是第三十届ＩＭＯ的一道竞赛题：“设ｎ和ｋ是正整数，Ｓ是平面上ｎ个点的集合，满足：（ｌ）Ｓ中任何三点不共线；（２）对Ｓ中的每一点Ｐ，Ｓ中存在ｋ个点与Ｐ距离相等．证明：ｋ＜．（第三题）对于这个困难问题，我们来提出一个具有...     

Thermoelectric properties of two-dimensional hexagonal indium–VA

The electrical properties and thermoelectric(TE) properties of monolayer In–VA are investigated theoretically by combining first-principles method with Boltzmann transport theory. The ultralow intrinsic thermal conductivities of 2.64 W·m~(-1)·K~(-1)(InP), 1.31 W·m~(-1)·K~(-1)(InAs), 0.87 W·m~(-1)·K~(-1)(InSb), and 0.62 W·m~(-1) K~(-1)(InBi) evaluated at room temperature are close to typical thermal conductivity values of good TE materials(κ 2 W·m~(-1)·K~(-1)). The maximal ZT values of 0.779, 0.583, 0.696, 0.727, and 0.373 for InN, InP, InAs, InSb, and InBi at p-type level are calculated at 900 K,which makes In–VA potential TE material working at medium-high temperature.     

使用多线程技术提高VR应用的性能

VR系统十分复杂，计算机的处理任务十分繁重，处理器的处理速度跟不上应用提出的新要求。以常用的VR工具软件WorldToolKits为例，在建立好场景图并且进入仿真循环后，除了完成一般的操作系统的任务之外，计算机在每一个仿真步中的任务有：读入VR设备传感器的数据；调用仿真任务；根据输入更新场景中的仿真对象；调用仿真事件、虚拟物体执行仿真任务；虚拟物体沿路径前进一步；进行物体的渲染。如果使用虚拟装配系统进行复杂机械产品的虚拟装配，系统一方面要进行复杂零部件的渲染；另一方面在装配过程中还需要进行碰撞检测和干涉检查；另外，通常在VR系统中包含有数据手套、头盔和跟踪定位装置等硬件设备，而系统在每一帧都需要采集这些设备传感器的数据，这些操作都需要消耗大量的处理器资源。     

面向新一代存储计算的二维铁电半导体

存算一体化是后摩尔时代突破性能与功耗瓶颈的一个潜在发展方向。近年来兴起的二维铁电半导体由于兼具非易失性铁电极化和半导体特性,适合用于存算一体器件,因此在短短几年内迅速成为研究热点。本文作为“先进算力技术”的第一篇,介绍了存算一体化的历史背景、二维铁电半导体的物理图像以及典型器件的作用机制。本文不仅可以作为未来计算技术领域的一般性了解,本文附录给出的PPT课件也可以作为大学物理等课程中“电磁学”相关篇章的有益补充。     

Insights into the adsorption of water and oxygen on the cubic CsPbBr3 surfaces: A first-principles study

The degradation mechanism of the all-inorganic perovskite solar cells in the ambient environment remains unclear. In this paper, water and oxygen molecule adsorptions on the all-inorganic perovskite (CsPbBr₃) surface are studied by density-functional theory calculations. In terms of the adsorption energy, the water molecules are more susceptible than the oxygen molecules to be adsorbed on the CsPbBr₃ surface. The water molecules can be adsorbed on both the CsBr- and PbBr-terminated surfaces, but the oxygen molecules tend to be selectively adsorbed on the CsBr-terminated surface instead of the PbBr-terminated one due to the significant adsorption energy difference. While the adsorbed water molecules only contribute deep states, the oxygen molecules introduce interfacial states inside the bandgap of the perovskite, which would significantly impact the chemical and transport properties of the perovskite. Therefore, special attention should be paid to reduce the oxygen concentration in the environment during the device fabrication process so as to improve the stability and performance of the CsPbBr₃-based devices.     

柴油机多品位余热回收低损跨临界联合循环

为高效低损回收柴油机多品位余热,本文提出了一种跨临界有机朗肯联合循环,其中高温级循环用于回收温度较高的发动机排气余热和废气再循环(EGR)余热,低温级循环回收发动机冷却水余热、增压空气余热、与高温级循环换热后的排气余热和EGR余热。本文对联合系统高温级工质选择多种高温型工质,并对系统热效率、回收功、效率及整体效率随高温级最大压力的变化规律进行模拟分析。结果表明存在一个最优的高温级最大压力P_(maxh),使得随着P_(maxh)的增大,系统热效率先上升后下降,工质均存在热效率η(th)的最大值。甲苯不论是热效率还是效率均表现出较好的性能,并且使柴油机效率提高了6.86个百分点。     

Tunneling field effect transistors based on in-plane and vertical layered phosphorus heterostructures

Tunneling field effect transistors(TFETs) based on two-dimensional materials are promising contenders to the traditional metal oxide semiconductor field effect transistor, mainly due to potential applications in low power devices. Here,we investigate the TFETs based on two different integration types: in-plane and vertical heterostructures composed of two kinds of layered phosphorous(β-P and δ-P) by ab initio quantum transport simulations. NDR effects have been observed in both in-plane and vertical heterostructures, and the effects become significant with the highest peak-to-valley ratio(PVR)when the intrinsic region length is near zero. Compared with the in-plane TFET based on β-P and δ-P, better performance with a higher on/off current ratio of ～ 10~6 and a steeper subthreshold swing(SS) of ～ 23 m V/dec is achieved in the vertical TFET. Such differences in the NDR effects, on/off current ratio and SS are attributed to the distinct interaction nature of theβ-P and δ-P layers in the in-plane and vertical heterostructures.     

一元二次方程求根公式的检验

一元二次方程求根公式的检验３１６００４舟山师专歌今波利亚说：“‘文字题’（即用字母的问题）较之‘数字题’更经得起试验，而且试验起来也更有趣味”（《怎样解题》）．又认为“在低年级和高年级，讨论所提出来的定理（‘讨论或考察定理的某些特例及它的一些更直接的...