关于振动热能的计算

本文通过对多种振动系统动热能的分析和计算,指出了振动势能是系统相对于平衡位置的各种势能增量之和,它只与位移有关,并可用一通式表示。     

兰州重离子加速器国家实验室(NLHIAL)的今天与明天

本文介绍了HIRFL的工作状况和发展,简要报道了NLHIAL的科学活动,提出了建立与HIRFL配套的重离子冷却储存环(CSR)的设想。This paper reports on the current status of operation and development of the Heavy IonResearch Facility in Lanzhou (HIRFL), and introduces briefly the outline of the scientific activities inNLHIAL. In addition, a proposal concerning building a Cooler Storage Ring (CSR) for heavy ions incombination with HIRFL is presented.     

小型高真空多层绝热杜瓦日蒸发率性能研究

日蒸发率是评价高真空多层绝热杜瓦保冷性能最重要的技术参数。该文对日蒸发率的影响因素进行了总结,重点介绍了储存压力和环境温度对日蒸发率的影响。以充满率为90%的210L小型杜瓦为例,测试了日蒸发率的变化规律。结果表明,杜瓦的日蒸发率与储存压力成正比,同时日蒸发率的波动随着储存压力的升高而增大,且环境温度对日蒸发率的影响出现延迟。     

HIRFL-CSR实验环团簇内靶的首批测试实验

内靶装置是兰州重离子冷却储存环(HIRFL-CSR)实验环的一个重要的插入件,也是世界上第一个嵌入在重离子储存环中的内靶装置,它位于HIRFL-CSR实验环的一个直线段.团簇内靶具有传统外靶所不具备的一些优点,如高亮度、高精度和高灵敏度等.这些优点可使我们在内靶实验平台上进行一些高精度的物理实验.为满足不同物理实验的需求,内靶可以有两种工作模式:非极化靶运行模式和极化靶运行模式,用于为实验环内的物理实验提供厚度为1011~1013atoms/cm2的非极化靶和极化靶.团簇靶是属于非极化靶运行模式,它采用超声喷气和冷凝相结合的方法获得团簇粒子束,并在碰撞靶室中与环内束流相碰撞,未反应的团簇束被收集级抽走.团簇内靶可以提供靶密度约为2×1013atoms/cm2的Ne、Ar、Kr、Xe和N2、CH4等团簇束.目前已完成了团簇靶的现场安装和准直,并进行了真空达标、喷嘴冷却和稳定性等首批测试实验.本文主要介绍团簇靶的工作原理和首批测试实验结果.     

衍射极限储存环束流注入物理方案的设计及模拟

衍射极限储存环（DLSR）作为第四代同步辐射光源，正得到世界各国的大力发展和建设。如何在尽量减小对存储束流扰动情况下，高效率地将束流注入到储存环中，是衍射极限储存环设计与运行中的重要课题之一。传统的局部凸轨注入法有着很长的历史，应用广泛且技术成熟，但是传统凸轨注入法会对存储束流造成扰动，且衍射极限储存环的动力学孔径较小，这给传统凸轨注入法的应用带来了困难。为了解决这些问题，改进了一些传统的离轴注入法，提出并发展了一些在轴的注入方法。合肥先进光源（HALF）是规划建设中的衍射极限储存环光源，基于HALF储存环的物理设计方案，设计并应用了几种离轴或在轴的注入方案，通过粒子跟踪和模拟的方法验证了它们的可行性并研究了注入效率等物理问题，并对模拟结果进行了讨论和总结。     

氢气低温液化与储运技术进展

全面概括和总结了国内外氢气液化、储存和运输的技术现状和发展前景。从质量密度和体积密度的角度考虑，液氢是一种极为理想的储氢方式；现有氢气低温液化(火用)效率和液化率仍处较低水平，单位产液氢功耗巨大，氢气透平膨胀机尚未实现国产化，液化设备成本高昂；液氢存储的主要难点为液化难、储罐的费用高、蒸发损失大；车用液氢储罐输氢除了绝热、泄漏问题外，还要考虑隔震、抗冲击等安全问题。氢气液化、储存、输送等环节的工艺技术仍需进一步研究，以提高效率和安全性、降低成本。     

储存环全相干光源

基于电子储存环的同步辐射具有稳定性高、光子能量范围广、支持多用户等优势，但其辐射相干性较差。在储存环上实现相干辐射不但可以大幅提高辐射光的相干性，同时还可以极大地提高特定频谱范围内的光通量、亮度和能量分辨率。随着光通量的提高，其功率有可能达到工业应用的水平，这将拓展光源的应用范围。回顾了基于电子束储存环的各类相干光源的发展历史，并展望其发展趋势。     

金属硫化物基钾离子电池负极：储存机制和合成策略

Rechargeable potassium-ion batteries (PIBs), with their low cost and the abundant K reserves, have been promising candidates for energy storage and conversion. Among all anode materials for PIBs, metal sulfides (MSs) show superiority owing to their high theoretical capacity and variety of material species. Nevertheless, the battery performance of MSs is hindered by many factors such as poor conductivity, low ion diffusivity, sluggish interfacial/surface transfer kinetics, and drastic volume changes. In this review, the electrochemical reaction mechanisms, challenges, and synthesis methods of MSs for PIBs are summarized and discussed. In particular, the most common synthesis methods of MSs for PIBs are highlighted, including template synthesis, hydro/solvothermal synthesis, solid-phase chemical synthesis, electrospinning synthesis, and ion-exchange synthesis. During the potassium storage process, the two-dimensional layered MSs follow the intercalation/extraction mechanism, and the MSs with inactive metal undergo the conversion reaction, whereas the metal-active MSs follow the conversion-alloying reaction mechanism. Given the inherent properties of MSs and the reactions they undergo during cycling, when used as anodes for PIBs, such materials experience a series of problems, including poor ion-/electron-transport kinetics, structural instability, and loss of active material caused by the dissolution of discharged polysulfide products and the occurrence of side reactions. These problems can be solved by optimizing the methods for synthesizing MSs with an ideal composition and structure. The template method can precisely prepare porous or hollow-structured materials, the hydro/solvothermal method can alter the thickness or size of the material by adjusting certain synthesis parameters, and the one-dimensional-structured material obtained via electrospinning often has a large specific surface area, all of which can shorten the transport pathway for potassium ions, thereby improving the performance of the battery. The ion-exchange method affords difficult-to-synthesize MSs via anion- or cation-exchange, in which the product inherits the structure of the starting material. The solid-phase synthesis method makes it possible to combine MSs with other materials. Combinations with materials such as carbon or other MSs helps to provide sufficient buffer space for the volume expansion of MSs during cycling, while promoting electron transport and improving the potassium-storage properties of the anodes. Therefore, this review aims to highlight the current defects of MS anodes and explore the construction of their ideal architecture for high-performance PIBs by optimizing the synthesis methods. Ultimately, we propose the possible future advancement of MSs for PIBs.