骨折内固定材料的研究进展

传统的骨折内固定材料在临床应用过程中出现了许多亟待解决的问题,如应力遮挡等,这些问题不但与材料的设计有关,而且与所采用的材料有密切关系.在概述骨折内固定材料的发展历史及目前所存在的主要问题的基础上,阐述了骨折内固定材料近些年来的新进展及今后的发展前景.     

A new bubble-point-pressure correlation for the binary LiBr/H2O solution

In accord with the increasing concern about the global environmental issues, the absorption refrigeration heat-pump systems are currently being considered very promising and attractive. For the purpose of supporting the advanced R&D technology in this area, we have developed a novel correlation to represent the bubble-point pressures of LiBr H₂O solutions. The developed correlation covers the most extensive range of validity ever proposed: 273–483 K for temperatures, 0.05 kPa to 1.0 MPa for pressures. and 29 76 wt% LiBr for concentrations.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994. Boulder, Colorado, U.S.A.     

中国冷库的现状与发展趋势

本文从的设计建造、制冷工艺和管理维护这三个方面，介绍了近三年来中国冷库的现状，说明中国冷库正朝着灵活、自动化、节能和环保的方向进一步发展。     

部分种子成分的特征X射线在等效生物材料中衰减的测定

用Ｓｉ（Ｌｉ）探测器实现了Ｎａ、Ｍｇ、Ｓ、Ｃｌ的特征Ｘ射线在有机膜中的相对衰减以及与Ｏ、Ｋ元素的特征Ｘ射线能量相当的Ｘ射线或轫致辐射在有机膜中的相对衰减，分别得出了它们减的数学描述，并把实验得到不同能量的Ｘ射线在有机膜中的质量吸收系数与Ｂｅｒｋｅｌｅｙ的ＯＣＧ软件计算出的结果相比，相关都小于３０％。     

富勒烯光限幅技术研究新进展

介绍了富勒烯激发态吸收光限幅以及激发态吸收和其它非线性光学效应共同作用的复合型光限幅技术的研究新进展。分析了今后的研究方向。     

钇铁石榴石薄膜材料的光吸收谱及Bi,Al掺入对谱的影响研究

采用单离子晶场跃迁模型，拟合出钇铁石榴石（ＹＩＧ）薄膜材料的光吸收谱，与实验谱吻合得较好。从实验和理论上分析了（ＢＩＡＩ）ＹＩＧ 薄膜材料的光吸收谱，结果表明，Ａｌ３＋离子的作用如同稀释剂一样，减小了光吸收，Ｂｉ３＋离子由于其强的自旋轨道耦合作用，增大了跃迁振子强度和跃迁线宽，从而增大了光吸收损耗，在此基础上所作的（ＢｉＡｌ）ＹＩＧ的理论谱与实验谱符合得较好。     

Conceptual design of a high-efficiency absorption cooling cycle

The search for high-efficiency, gas-fired cooling cycles has led to the development of dual-loop absorption machines with cooling coefficients of performance (COPs) in the 1.2 to 1.7 range. This increased performance may call for high generator temperatures, new working fluids or new materials of construction. In most cases, two different sets of working fluids are required. The conceptual design presented here is aimed at obtaining high efficiencies with relatively low temperatures, employing only one set of fluids. The concept consists of two loops coupled in a configuration aimed at minimizing the loss of thermodynamic availability incurred when transferring refrigerant between the loops. The working fluid pair is a solution of lithium bromide-water. The calculated COPs are of the order of 1.8. The cycle relies on an elaborate evaporator-absorber combination. The paper presents the conceptual design, the critical assumptions, and the performance calculations for the concept.     

Absorbability of Calcium From Common Beans

Absorption of calcium from white, red, and pinto beans, labeled with ⁴⁵Ca, was measured in 24 women in a three-way randomized design using a calcium load of 72 mg and milk as the referent. Fractional absorption for the three beans averaged 0.219 ± 0.047 and did not differ by type. Milk calcium absorption at the same load was more than two times higher, 0.451 ± 0.088 (P < 0.001). Oxalate content averaged 0.34%, and phytate averaged 1.7%, a stoichiometric excess relative to calcium. To evaluate the relation of phytate to reduced absorbability, labeled pinto beans were pre-treated with phytase and fed to 10 subjects. Fractional absorption rose, averaging 0.318 ± 0.071, (P <0.01 vs. untreated beans), but was significantly below that of milk. The difference was partly accounted for by phytate, with the remainder probably due to relatively high oxalate.     

半导体陶瓷致冷材料的性能与结构

采用新的陶瓷工艺技术,在气氛保护条件下,通过固相烧结反应法制备出温差电多晶材料。对膺三元固溶体化合物 P 型(72%Sb_2Te_3+25%Bi_2Te_3+3%Sb_2Se_3)和 N 型(90%Bi_2Te_3+5%Sb_2Te_3+5%Sb_2Se_3)的掺杂陶瓷样品进行了性能与结构研究。找到了最佳工艺制度。样品性能参数为:N 型:α=186μV/K σ=1250Ω~(-1)·cm~(-1) λ=14.7mW/(cm.K) Z=2.9×10~(-3)/KP 型:α=220μV/K σ=900 Ω~(-1)·cm~(-1) λ=14.0mW/(cm.K) Z=3.1×10~(-3)/K     

Performance of absorption refrigeration cycle at maximum cooling rate

The influence of irreversibility of finite-rate heat transfer on the performance of an absorption refrigerator is investigated using an endoreversible cycle model with continuous flow. The cooling rate is adopted as an objective function for refrigerator optimization. The maximum cooling rate and the corresponding coefficient of performance are derived. The optimal performance with respect to heat transfer areas of the refrigerator is analysed. In addition, certain significant conclusions are reached.