平面热源法测量均质固体材料的蓄热系数

本文建立了平面热源法实验条件下的非稳态导热的数学模型 ,应用拉普拉斯变换和热四端网络法 ,求解了实验测量系统的解析模型和各种相应的简化模型。根据参数估计的基本原理 ,对模型中的待估计参数做了灵敏度分析。建立了实验测量系统 ,可以满足 2 0～ 2 0 0℃环境下固体材料蓄热系数测量的需要。测量了常温下几种材料的蓄热系数 。

煤矸石质固土材料固化土的耐久性试验研究

为评价煤矸石质固土材料固化土的耐久性能,研究了煤矸石质固土材料固化土的耐水性能、耐干湿循环性能、抗冻融性能以及耐酸、碱、盐腐蚀性能,通过与普通硅酸盐水泥固化土的性能对比,对煤矸石质固土材料固化土的耐久性能进行了试验研究。结果表明,煤矸石质固土材料固化土14 d耐水稳定系数为0.94,耐干湿循环交替系数为0.898,抗冻系数为0.9,煤矸石质固土材料固化土在这3项性能上均优于水泥加固土。耐酸碱盐性能方面,煤矸石质固土材料固化土耐酸性略逊于水泥固化土,而耐碱和盐腐蚀性能明显优于水泥固化土。

氟化物激光晶体及其在固体激光器中的应用

固体激光基质材料可以分为晶体、玻璃、光纤和陶瓷。相对于其他材料,晶体的优点表现在热导率高、荧光谱线窄、硬度比较大等方面,因而在固体激光器中获得了更广泛的利用。作为一类重要的激光基质材料,氟化物激光晶体种类多,研究活跃,一直是激光材料的热点之一。介绍CaF_2、LaF_3、MnF_2、ZnF_2、KMgF_3等激光晶体基质以及Nd、Er、Cr、Yb、Co等离子掺杂激光晶体,特别是MgF_2、YLF、LiSAF等激光晶体,探讨了这些材料的发光特性,并与YAG等常用氧化物激光晶体进行了比较。与其他激光介质相比,氟化物激光晶体具有自发荧光寿命长、折射率受温度影响小、热透镜效应小、热稳定性好等优点,决定了其在固体激光器领域特殊的应用价值。在对氟化物晶体的激光器应用分析基础上,展望了氟化物激光晶体未来的研究前景。

Isolation of Leptospirillum ferriphilum by single-layered solid medium

According to physiological and biochemical characteristics of Leptospirillum ferriphilum, a strain of object bacteria was isolated successfully. Bacteria were enriched by selective liquid medium and plated on designed single-layered agar solid medium. Colony was cultured and bacteria were collected. The morphologies of the object bacteria were observed using crystal violet staining, scanning electron microscope（SEM） and transmission electron microscope （TEM）. The result of 16S rDNA identification shows that this bacterium belongs to Leptospirillum ferriphilum and it is named as Leptospirillum ferriphilum strain D1. These results indicate that this new single-layered agar solid medium is efficient and physiological-biochemical characteristics show that the optimum simple for isolation of Leptospirillum ferriphilum. Additionally, initial pH value and its growth temperature are 1.68 and 40℃.

Vertical transportation system of solid material for backfilling coal mining technology

For transportation of solid backfill material such as waste and fly ash from the surface to the bottom of the shaft in a fully mechanized backfilling coal backfilling coal mining technology, we developed a new vertical transportation system to transport this type of solid backfill material. Given the demands imposed on safely in feeding this material, we also investigated the structure and basic parameter of this system. For a mine in the Xingtai mining area the results show that: (1) a vertical transportation system should include three main parts, i.e., a feeding borehole, a maintenance chamber and a storage silo; (2) we determined that 486 mm is a suitable diameter for bore holes, the diameter of the storage silo is 6 m and its height 30 m in this vertical transportation system; (3) a conical buffer was developed to absorb the impact during the feeding process. To ensure normal implementation of fully mechanized backfilling coal mining technology and the safety of underground personnel, we propose a series of security technologies for anti-blockage, storage silo cleaning, high pressure air release and aspiration. This vertical transporting system has been applied in one this particular mine, which has fed about 4 million tons solid material with a feeding depth of 350 m and safely exploited 3 million tons of coal.

Density-functional-theory formulation of classical and quantum Hooke's law

A fundamental property of solid materials is their stress state. Stress state of a solid or thin film material has profound effects on its thermodynamic stability and physical and chemical properties. The classical mechanical stress （σ^M） originates from lat- tice strain （e）, following Hooke＇s law： σ^M=Cε, where C is elastic constant matrix. Recently, a new concept of quantum electronic stress （o-QE） is introduced to elucidate the extrinsic electronic effects on the stress state of solids and thin films, which follows a quantum analog of classical Hooke＇s law： ~QE=E（An）, where E is the deformation potential of electronic states and An is the variation of electron density. Here, we present mathematical derivation of both the classical and quantum Hooke＇s law from density functional theory. We further discuss the physical origin of quantum electronic stress, arising purely from electronic excitation and perturbation in the absence of lattice strain （g=0）, and its relation to the degeneracy pressure of electrons in solid and their interaction with the lattice.

Artificial cathode solid electrolyte interphase to endow highly stable lithium storage of FeF_(2) nanocrystals

Iron difluoride(FeF_(2))is considered a highcapacity cathode material for lithium-ion batteries.However,its specific capacity and stability are limited by the poor electrochemical kinetics of conversion reactions.Herein,the conversion reaction is confined in a localized nanosized space by encapsulating FeF_(2) nanoparticles in polymer gelatin.The FeF_(2) nanocrystal-coated polyvinylidene fluoride-based layer(defined as Fe F_(2) @100%G-40%P)was synthesized by glucoseassisted in-situ gelatinization to construct an artificial cathode solid electrolyte interphase via a solvothermal process.Thanks to the improved kinetics of the localized conversion reaction,the obtained FeF_(2) @100%G-40%P electrodes show good cyclic stability(313mAhg^(-1) after 150 cycles at 100 mAg^(-1) ,corresponding to a retention of 80%)and a high rate performance(186.6 mAhg^(-1) at 500 mAg^(-1)).