掺杂对酸法铁黄制备过程的影响

研究了酸法铁黄制备过程中掺杂Ｚｎ＾２＋，Ｎ＾２＋，Ｃｄ＾２＋，Ｃｒ＾３＋，ＰＯ４＾３－等离子对晶种及铁黄形态和结构的影响，并初步探讨了杂质的作用机制。研究发现：掺杂离子改变晶种及铁黄的形态和结构，掺杂Ｚｎ＾２＋可增加晶种轴比，减少枝权和孪晶，优化铁黄形态。     

High-Entropy Borides under Extreme Environment of Pressures and Temperatures

The high-entropy transition metal borides containing a random distribution of five or more constituent metallic elements offer novel opportunities in designing materials that show crystalline phase stability, high strength, and thermal oxidation resistance under extreme conditions. We present a comprehensive theoretical and experimental investigation of prototypical high-entropy boride (HEB) materials such as (Hf, Mo, Nb, Ta, Ti)B₂ and (Hf, Mo, Nb, Ta, Zr)B₂ under extreme environments of pressures and temperatures. The theoretical tools include modeling elastic properties by special quasi-random structures that predict a bulk modulus of 288 GPa and a shear modulus of 215 GPa at ambient conditions. HEB samples were synthesized under high pressures and high temperatures and studied to 9.5 GPa and 2273 K in a large-volume pressure cell. The thermal equation of state measurement yielded a bulk modulus of 276 GPa, in excellent agreement with theory. The measured compressive yield strength by radial X-ray diffraction technique in a diamond anvil cell was 28 GPa at a pressure of 65 GPa, which is a significant fraction of the shear modulus at high pressures. The high compressive strength and phase stability of this material under high pressures and high temperatures make it an ideal candidate for application as a structural material in nuclear and aerospace fields.     

The Preparation of Amorphous ZrC/Nanocrystalline Ni Multilayers and the Resistance to He+ Irradiation

The development of accident-tolerant materials is of great significance for preventing the zirconium–water reactions and improving the inherent safety of nuclear reactors. In this study, ZrC/Ni multilayers with average layer thicknesses of 5, 10, 20, 50, and 100 nm were designed and successfully fabricated by magnetron sputtering. The characterization results of GIXRD, SEM, AFM, TEM, etc., show that the series of films are mainly composed of alternately deposited Ni crystalline layers and ZrC amorphous layers, and the interface is clear. The films were irradiated with 50 keV He⁺ with a fluence of 1.0 × 10¹⁷ ions/cm² at room temperature, and the films with different layer thicknesses kept the original phase composition. It was found that an amorphous transition layer with a thickness of about 30 nm appeared between the amorphous and crystalline interface of the 100 nm film by TEM characterization. The analysis shows that this layer is formed by the mixing of Ni and Zr elements induced by irradiation, which is not conducive to He⁺ migration and produces large-sized helium bubbles. The appearance of the transition layer improves the irradiation stability of the amorphous/crystalline composite film, thus providing a theoretical basis for the application of this type of material in fuel cladding.     

数据挖掘在生物医学数据分析中的应用

随着信息技术的发展,采集、存储和管理数据的手段日益完善,数据挖掘学科应运而生。文章阐述数据挖掘的概念;通过给出各种数据挖掘方法在生物医学研究领域中的应用实例,分析数据挖掘与生物医学领域中统计学的关系,并就国内生物医学数据挖掘的应用现状、需要解决的问题以及今后研究的发展方向等进行综述。     

海洋天然产物研究概述

近年来海洋天然产物越来越引起科学家们的注意,在浩瀚的海洋中存在着大量令人激动、活性独特、结构新颖的次生代谢产物。海洋天然产物已成为发现重要先导药物和新的生物作用机制的主要源泉。对目前海洋天然产物研究概况进行综述,其中重点介绍大环内酯类和聚醚类等化合物。     

生物材料人工气管的设计与动物实验研究

目的：通过筛选适宜的生物材料和选用特殊的成型工艺自行研制新型人工气管假体，探讨其用于长段气管缺损重建的可行性。方法：根据理想化气管替代物的要求，设计出I型人工气管：由聚丙烯单丝、聚乙丙交酯纤维纺织成直管状网管，内壁涂以聚氨酯薄膜和胶原蛋白，涂层材料不能透过外壁网孔，外壁采用胶原蛋白-羟基磷灰石多孔状海绵覆盖。作为对照的II型人工气管，网管结构与I型相同，内外壁均涂以聚氨酯。分别将I型、II型人工气管用于实验组（8只）和对照组（4只）动物，构建犬颈部气管置换与重建的动物模型。结果：实验组犬术后人工气管假体能迅速被宿主气管周围组织包绕而达到生物学固定，假体在位良好，吻合口肉芽生长不明显；假体内腔可见不规则黏膜上皮生长，色较苍白，未铺覆内腔全长；包绕假体的周围组织中可扪及散在的大小不等的硬质骨性结构；动物存活时间长。而对照组术后均出现不同程度的假体松脱现象，并发生局部漏气、感染及狭窄等并发症。结论：该生物材料人工气管可用于长段气管置换重建手术，具有一定的开发利用价值和临床应用前景。     

骨碎补类生药显微鉴定研究Ⅱ.粉末特征

对12种骨碎补类生药粉末进行了鉴定,列出了检索表。其鉴别要点是;(1)非腺毛的特征;(2)有无完整的鳞片基及鳞片细胞的形状和毛状突出物的长短;(3)薄壁细胞的形状及细胞壁增厚程度;(4)纤维状细胞的形状及表面特征;(5)网纹细胞、石细胞等的存在与否;(6)表皮细胞的形状及排列。     

钛-75种植后骨界面X线观察及顶出试验研究

目的：研究钛－７５（钛铝相锆）合金的组织相容性。方法：成年杂种犬８只,分别于犬双铡后腿股骨内侧手术植入种植体,一侧为纯钛,另一侧为钛７５合金。分别于术后３,６,１２,２４个月处死动物,肉眼观察种植体表面,摄Ｘ线片观察种植体－骨界面,采用顶山试验测试种植体－骨界面的结合强度。结果：钛７５种植体表面与钛一样在不同种植程期中均具有良好的光泽,各观察期中,钛－７５与纯钛种植体－骨界面Ｘ线表现相似,均无骨质     

亳州3种引种药材气相色谱研究初报

目的：应用气相色谱法研究亳州３种引种药材化学成分及含量的变化。方法：取道地药材对照品,与引种药材作性状、气相色谱图谱图谱分析比较。结果：引种药材在其性状、化学成分上均有较大变化。结论：引种药材能还替代道地药材进入市场还有待于进一步研究。     

腹腔镜胃外科手术缝合技术与缝合材料选择中国专家共识(2021版)

胃外科手术中各种缝合、吻合技术及缝合材料的规范化应用与合理选择对控制术后并发症具有重要意义.中华医学会外科学分会于2008年制定了《胃肠吻合专家共识(2008)》,在此基础上,于2018年修订更新,完成《胃肠手术缝合技术与缝合材料选择中国专家共识(2018版)》[1],为国内该领域的手术操作提供了理论指导与实践规范.随...