大连化物所高比能量锂硫二次电池研究取得新进展

<正>近日,中国科学院大连化学物理研究所燃料电池研究部陈剑研究员领导的先进二次电池研究组(DNL0306组)在高比能量锂二次电池方面取得新进展,研制成功额定容量15 Ah的锂硫电池,并形成小批量制备能力。这是迄今世界上已见报道的容量最大的锂硫电池。第三方(中国科学院物理研究所)检测结果表明,电池的比能量大于430 Wh/kg,超过了Sion Power公司报道的由其研制的锂硫电池的技术指标     

基于XeF (C-A)激光激励的自发拉曼散射技术研究

针对自发拉曼散射技术应用于实际燃烧场参数测量时面临的主要技术难题,采用XeF(C-A)激光作为激励光源,开展了自发拉曼散射技术实验研究。通过分析拉曼散射过程对光源参数的要求,优化了XeF(C-A)激光器部分参数,建立了自发拉曼散射诊断系统,实现了气体介质主要组分浓度在线测量,对比了XeF(C-A)激光与主流激光作为拉曼散射光源的优缺点。结果表明:与现有主流光源相比,具有脉冲能量大、微秒级脉宽,位于可见光波段等特点的放电抽运XeF(C-A)激光非常适合用作自发拉曼散射激励光源。     

风电与压缩空气储能系统的能量转化特性研究

先进绝热压缩空气储能(AA-CAES)是解决风电不稳定性问题的一种能量存储技术。本文以热力学理论为基础,建立了风电与AA-CAES集成系统的理论模型并开展了仿真模拟工作,对集成系统在额定、扰动工况下的能量转化规律进行了对比和分析。结果表明集成系统存在电能、空气内能和水的热能的能量转化,内能与热能的转化随过程进行而变化,且两者的变化规律相反;扰动风速通过改变功率输入影响压气机效率,进而影响电能向空气内能的转化,但对系统热能的影响相对较小。     

基于CO_2吸收增强气化的氨电联产操作条件分析

本文以煤和低浓度煤层气为原料,采用CO_2吸收增强气化,在造气工段制得φ(H_2)/φ(N_2)=3、φ(CO_2+CO)≤0.30%的粗煤气,直接进入气体精制岗位,并取消常规制气的补氮过程或替代空气气化;采用单元建模和流程模拟的方法对系统可行性和适宜操作条件进行分析;预报煤和煤层气共气化的产物分布,提出满足精制岗位进口气体品质要求的制气温度、压力、水煤比、钙煤比和煤气流量等参数;分析循环倍率对合成氨产量、系统净输出功等参数的影响,得到实现系统能量自平衡、且合成氨能耗最低的循环倍率。理论分析表明,该流程可用于合成气制备及氨电联产。     

Ground-State Properties of Superfluid Fermi Gas in Fourier-Synthesized Optical Lattices

By employing the balance condition between the lattice potential and the interatomic interaction, we study the ground state solutions of superfluid Fermi gases in Fourier-synthesized （FS） optical lattices. The average energy of the ground state, the atoms number, and the atom density distribution of the Fermi system are analytically derived along the Bose–Einstein condensation （BEC） side to the Bardeen–Cooper–Schrieffer （BCS） side. We analyze the properties of ground state solutions at both the BEC limit and unitarity in FS optical lattices. It is found that the relative phase α between the two lattice harmonics impacts greatly on the properties of the ground state of the superfluid Fermi gas. Especially in the BCS limit, when α=π/2, the average energy presents an exponential form with the increase of the potential depth of the lattice harmonics v2. Meanwhile, there exits a minimal value. Moreover, due to the Fermi pressure, the atom density distribution at unitarity is more outstretched than that in the BEC limit. The average energy at unitarity is apparently larger than that in the BEC limit. The properties of the ground state solution exhibit very different behaviors when the system transits from the BEC side to the BCS side.     

Temperature Dependence of Emission Properties of Self-Assembled InGaN Quantum Dots

Emission properties of self-assembled green-emitting InGaN quantum dots （QDs） grown on sapphire substrates by using metal organic chemical vapor deposition are studied by temperature-dependent photoluminescence （PL） measurements. As temperature increases （15-300K）, the PL peak energy shows an anomalous V-shaped （redshift blueshift） variation instead of an S-shaped （redshift-blueshift-redshift） variation, as observed typically in green-emitting InGaN/GaN multi-quantum wells （MOWs）. The PL full width at half maximum （FWHM） also shows a V-shaped （decrease-increase） variation. The temperature dependence of the PL peak energy and FWHM of QDs are well explained by a model similar to MOWs, in which carriers transferring in localized states play an important role, while the confinement energy of localized states in the QDs is significantly larger than that in MOWs. By analyzing the integrated PL intensity, the larger confinement energy of localized states in the QDs is estimated to be 105.9meV, which is well explained by taking into account the band-gap shrinkage and carrier thermalization with temperature. It is also found that the nonradiative combination centers in QD samples are much less than those in QW samples with the same In content.     

Calculation of Higher-Order Foldy-Wouthuysen Transformation Hamiltonian

The Foldy-Wouthuysen Hamiltonian of a light atomic system that has an ma^8 contribution to energy levels is calculated. The case of a Dirac-Coulomb field is discussed. The results can be used for relativistic and radiative corrections to energy levels in the low-energy part. A divergent operator δ^2（r） emerges. This is probably due to the nature of the point-like charge source. The effective method of radiation calculation may be re-checked.     

Mechanical Properties of Sialic Foamed Ceramic and Applications in Defense Structure

Mechanical properties of a closed-cellular sialic foamed ceramic are investigated by compressive tests. The sialic foamed ceramic under uniaxial stress compression shows brittleness and the flow stress increases with the strain rate. The engineering stress-engineering strain curve under uniaxial strain compression could be divided into three stages： linear elasticity, collapsed plateau and densification. The unloading elastic modulus, Poisson ratio and energy absorption ability are discussed. Shelly cellular material made by sialic foamed ceramic is applied into the stress distribution layer in the defense structure. Field explosion experiments are performed for the sand based stress distribution layer and shelly cellular material based layer. Compared with sand, the shelly cellular material reduces the peak stress of the blast wave.     

带电体低速运动时电磁场的能量和动量

依据电磁场的相对论变换,计算了均匀带电球面、运动方向垂直于环面的通电螺绕环、运动方向平行于轴向的充电圆柱形电容器、运动方向垂直于板面的平行板电容器等4种带电体低速运动（v 虫 c）时电磁场的能量和动量。     

从能量角度分析电磁感应模型

对中学物理电磁感应问题中比较复杂的模型,其能量转化也相对复杂.如系统中有的导体在克服安培力做功,有的安培力在对导体做功,而又可能涉及其他外力的功,如牵引动力、重力、摩擦力的功等.弄清这些系统的能量转化过程才能深入认识这些模型.