FD—140型高灵敏测氡仪及其应用

FD—140型高灵敏测氡仪用于测量氡的浓度,测氡灵敏度可达15mBq/m~3 min。该仪器可用于普查与勘探铀矿床,也可用于找石油、煤、金、地下水和地震预报以及地质构造调查等方面。     

温度对Ni—P化学镀层结合力影响的研究

用弯曲法、划痕法研究了镀后加热温度对Ni-P化学镀层结合力的影响,结果表明:镀后退火温度越高,镀层结合力越好,但温度过高时,镀层硬度将下降。用金相观察及电子探针分析,探讨了镀后退火温度影响结合力的机理。结果指出:退火时将在镀层和基体界面上发生Ni与Fe的互扩散,形成Ni-Fe合金扩散层,从而提高了结合力。为了能在保证镀层硬度的前提下提高结合力,本文提出了二次镀覆的设想,获得较好试验结果。     

High-temperature sulfidation of Fe-Nb alloys

The sulfidation behavior of Fe-Nb alloys containing up to 30 w/o Nb was studied over the range of 600–900°C in 0.01 aim. S₂ vapor. All alloys were two-phase, consisting of an Fe-rich solid solution and Fe₂Nb, and followed the parabolic rate law at all temperatures. Scales consisted of two layers-an outer layer of FeS and an inner, complex layer which contained some FeS, FeNb₂S₄ (possibly some FeNb₃S₆), NbS₂, and intermetallic particles which were either completely or only partially sulfidized. Platinum markers were located always at the interface between the two layers, which corresponded to the original metal surface. Activation energies were 18±3 kcal/mol in close agreement with the 19.8 reported for pure iron. The sulfidation rate decreased markedly with increasing Nb content of the alloys. The decrease is attributed to increasing amounts of Fe₂Nb with increasing Nb, the net effect being that the diffusion path for outward iron diffusion through the inner layer is reduced as the Nb content increases. An analysis of the structure of NbS₂ reveals that it is easily intercalated with Fe between loosely bonded layers of S-Nb-S. The S-Nb-S layers are covalently bonded which results in very low diffusivities of either S or Nb in pure NbS₂. Although intercalated Fe tends to change the Van der Waal's type bonding between layers to more ionic or covalent, Fe diffuses readily between the layers in NbS₂. Intercalation of Fe also increases the concentration of sulfur defects in NbS₂, which in turn increases the diffusivity of sulfur. Nb was observed to be immobile. Thus, it is thought that either outward iron diffusion or inward sulfur diffusion in the inner layer is the rate-controlling step, in spite of the close agreement of activation energies with that of the sulfidation of pure iron.     

16MnR钢高压除氧器焊接接头裂纹的成因

本文采用电镜，Ｘ射线衍射分析、裂纹扩展速率ｄａ／ｄＮ及门槛值△Ｋｔｈ试验，研究了火力发电厂１６ＭｎＲ钢高压除氧器焊接接头裂纹的形成原因，结果表明，原发裂纹为延迟裂纹，运行工况下，裂纹以应力腐蚀裂纹方式扩展。     

离子氮化对镀铬层组织与性能的影响

研究了镀铬层经离子氮化后的组织和性能。分别用SEM、电子探针和X光衍射仪观察和分析了复合处理层剖面的组织、结构和成分,试验结果表明:离子氮化能使镀铬层的网状裂纹弥合,可明显提高了镀层表面硬度、结合力和耐蚀性。     

燃烧合成三元碳化合物Ti2AlC1-x

采用Ti，Al和C元素粉末为反应物原料，通过燃烧合成法首次成功地制备出了单相三元碳化合物Ti2AlC1-x。实验结果表明：若以“理想”晶体结构化学式Ti2AlC化学计量比为起始反应原料配比，燃烧产物主晶相为Ti2AlC2；以缺碳的非化学计量比(Ti2AlC1-x)为反应原料配比，即Ti：Al：C=3：1．5：1=2：1：0．7(摩尔比)，得到单相的燃烧产物Ti2AlC1-x。从热力学原理的角度探讨了不同原料摩尔配比对燃烧产物相组成的影响机理。     

NH4F及燃烧温度对燃烧合成长柱状Yb α-Sialon粉体的影响

采用SHS法合成了Yb α-Sialon粉体，采用XRD和SEM分析和研究了添加剂NH4F及燃烧温度对燃烧合成长柱状Yb α-Sialon相组成和形貌的影响。实验发现，在不同条件下，添加剂NH4F对燃烧合成长柱状α-Sialon的晶体形貌可以起到抑制和促进两个相反的作用。温度越高，晶体生长速率越大，反应降温越慢，晶体生长时间越长，长柱状晶体生长越完整。燃烧合成得到的长柱状α-Sialon粉体，在室温下，以酒精为介质经过30min以上的超声分散，可以达到较好的分散效果。     

基于Web services的WebGISVisA体系结构研究与实现*

针对目前网络地理信息系统体系结构难以实现Internet环境下的异构空间信息的互操作问题,深入分析其主要原因,在对现有网络地理信息系统的三层体系结构进行深入分析的基础上,提出一种基于Web services的网络地理信息系统体系结构(Web-based geographical information services visualization architecture,WebGISVisA).WebGISVisA体系结构通过Web services对各个地理信息系统组件进行包装,实现各个组件的跨平台操作,从技术上使得客户端和服务端达到了负载平衡,完成了WebGIS三维的虚拟现实,实现了在Internet下空间数据互操作和跨平台的功能,最大限度地达到数据共享.     

基于细观建模的堆石混凝土抗压试验的数值模拟

从细观结构的角度出发,将堆石混凝土视为堆石体与自密实混凝土组合形成的复合材料,利用MATLAB与ANSYS/LS-DYNA软件建立了三维有限元模型,然后在此基础上进行了堆石混凝土模型抗压试验的数值模拟.探讨分析了应变率和堆石与混凝土粘结强度对堆石混凝土的抗压强度的影响.结果表明:堆石混凝土的抗压强度随着应变率的增大而增大,且随着粘结强度的增大而增大,但是堆石混凝土对应变率的敏感性较高,对粘结强度的敏感性较低.     

Red Emissive Carbon Dots Prepared from Polymers as an Efficient Nanocarrier for Coptisine Delivery in vivo and in vitro

Negatively charged fluorescent carbon dots (CDs, E_m=608 nm) were hydrothermally prepared from thiophene phenylpropionic acid polymers and then successfully loaded with the positively charged anticancer cargo coptisine, which suffers from poor bioavailability. The formed CD-coptisine complexes were thoroughly characterized by particle size, morphology, drug loading efficiency, drug release, cellular uptake and cellular toxicity in vitro and antitumor activities in vivo. In this nano-carrier system, red emissive CDs possess multiple advantages as follows: 1) high drug loading efficiency (>96 %); 2) sustained drug release; 3) enhanced drug efficacy towards cancer cells; 4) EPR effect; 5) drug release tracing with near-infrared imaging. These properties indicated that red emissive CDs prepared from polymers could be used as a novel drug delivery system with integrated therapeutic and imaging functions in cancer therapy, which are expected to have great potential in future clinical applications.