Hydrogen Permeation Behavior of Zirconium Nitride Film on Zirconium Hydride

Hydrogen permeation barrier plays an important role in reducing hydrogen loss from zirconium hydride matrix when used as neutron moderator. Here, a composite nitride film was prepared on zirconium hydride by in situ reaction method in nitrogen atmosphere. The phase structure, morphology, element distribution, and valence states of the composite film were investigated by XRD, SEM, AES, and XPS analysis. It was found that the composite nitride film was continuous and dense with about 1.6 μm thickness; the major phase of the film was ZrN, with coexistence of ZrO₂, ZrO, and ZrN_0.36H_0.8; and Zr-C, Zr-O, Zr-N, O-H, and N-H bonds were detected in the film. The existence of ZrN_0.36H_0.8 phase and the bonds of O-H and N-H revealed that the nitrogen and oxygen in the film could capture hydrogen from the zirconium hydride matrix. The hydrogen permeation performance of nitride film was compared with oxide film by permeation reduction factor (PRF), vacuum thermal dehydrogenation (VTD), and hydrogen permeation rate (HPR) methods, and the results showed that the hydrogen permeation barrier effects of nitride film were better than that of oxide film. The zirconium nitride film would be a potential candidate for hydrogen permeation barrier on the surface of zirconium hydride.     

Safety assessment of potential food ingredients in canine hepatocytes

This research aimed to develop in vitro methods to assess hazard of canine food ingredients. Canine hepatocytes were harvested and cell viability of clove-leaf oil (CLO), eugenol (EUG), lemongrass oil (LGO), guanosine monophosphate (GMP), inosine monophosphate (IMP), sorbose, ginger-root extract (GRE), cinnamon-bark oil (CBO), cinnamaldehyde (CINA), thymol oil (TO), thymol (THYM), and citric acid were assessed with positive controls: acetaminophen (APAP), aflatoxin B1 and xylitol. Molecular Toxicology PathwayFinder array (MTPF) analyzed toxicity mechanisms for LGO. LC₅₀ for APAP was similar among human (3.45), rat (2.35), dog (4.26 mg/ml). Aflatoxin B1 had an LC₅₀ of 4.43 (human), 5.78 (rat) and 6.05 (dog) µg/ml; xylitol did not decrease viability. LC₅₀ of CLO (0.185 ± 0.075(SD)), EUG (0.165 ± 0.112), LGO (0.220 ± 0.012), GRE (1.54 ± 0.31) mg/ml; GMP (166.03 ± 41.83), GMP + IMP (208.67 ± 15.27) mM; CBO (0.08 ± 0.03), CINA (0.11 ± 0.01), TO (0.21 ± 0.03), THYM (0.05 ± 0.01), citric acid (1.58 ± 0.08) mg/ml, while sorbose was non-toxic. LGO induced upregulation of 16 and down-regulation of 24 genes, which CYP and heat shock most affected. These results suggest that in vitro assays such as this may be useful for hazard assessment of food ingredients for altered hepatic function.     

Effects of Co Addition on the Microstructure and Properties of Elastic Cu-Ni-Si-Based Alloys for Electrical Connectors

The properties and microstructure evolution of quaternary Cu-Ni-Co-Si alloys with different Ni/Co mass ratios were investigated. The microstructure and morphological characteristics of the precipitates were analyzed by using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The mechanical properties and conductivity of the alloys were significantly improved after the addition of Co. The grains presented an obvious growth trend with an increase in Ni/Co mass ratios, and the appropriate Co accelerated the recrystallization process. The δ-(Ni, Co)₂Si phases of the Cu-Ni-Co-Si alloys and δ-Ni₂Si phases of the Cu-Ni-Si alloys shared the same crystal structure and orientation relationships with the matrix, which had two variant forms: δ₁ and δ₂ phases. The precipitates preferential grew along with the direction of the lowest energy and eventually exhibited two different morphologies. Compared with that of the Cu-Ni-Si alloy, the volume fraction of precipitates in the alloys with Co was significantly improved, accompanied by an increase in the precipitated phase size. The addition of Co promoted the precipitation of the precipitated phase and further purified the matrix. A theoretical calculation was conducted for different strengthening mechanisms, and precipitation strengthening was the key reinforcement mechanism. Moreover, the kinetic equations of both alloys were obtained and coincided well with the experimental results.     

Numerical Simulation and Experimental Study on Compound Casting of Layered Aluminum Matrix Composite Brake Drum

The requirements of high-strength, wear-resistance and lightweight of brake drums have been continually increasing in recent years and any specific aluminum alloy or particle-reinforced aluminum matrix composites may not satisfy all the demands. Combining dissimilar materials to play their respective advantages is a solution to this problem. In this study, a compound casting method was used to combine solid SiC_p/A357 composite and a liquid 7050 aluminum alloy to prepare an aluminum matrix composite with a layered structure. The ProCAST numerical simulation software was used to predict the heat transfer in compound casting process and guide the preheating temperature of the wear-resistant ring in the experiment. An Optical Microscope (OM) and Scanning Electron Microscope (SEM) were used to observe microstructures around the solid–liquid bonding interface, the element distribution and phase component of which were analyzed by Energy Dispersive Spectroscopy (EDS) and mechanical properties were evaluated by microhardness and shear tests. The results showed that the interface of the layered aluminum matrix composite prepared by this method achieved complete metallurgical bonding and a transition zone formed on the solid surface. After T6 heat treatment, the average shear strength of the interface increased from 19.8 MPa to 33.8 MPa.     

某镇居民健康知识水平调查分析

目的掌握雁栖镇居民健康知识水平和变化趋势,探索其影响因素,为雁栖镇的健康教育干预策施提供依据。方法采取多阶段整群随机抽样的方法抽取在雁栖镇居住达1年以上、年龄18~79岁的常住人口200人作为被调查对象进行问卷调查。调查内容主要包括基本情况,健康生活方式,安全与急救,基本医疗与保健,慢性病预防,传染病与地方病,基本卫生行为,电视相关内容等八部分组成。结果雁栖镇居民健康知识的总体水平为53%。结论居民具备健康知识的水平仍然很低,应大力推进健康促进与健康教育工作,开拓健康教育的新思路和方法,提高居民健康知识水平需要人群自身的参与与提高,逐步提高全镇居民的健康知识水平的知晓率。     

某镇糖尿病患病率流行特征

目的了解北京市怀柔区雁栖镇常住人口糖尿病患病率及其相关影响因素。方法对25岁及以上常住人口5017人,其中居民1429人,农业人口3588人,进行了糖尿病流行病学调查。禁食8h后进行口服葡萄糖耐量试验。结果根据WHO诊断标准,雁栖镇糖尿病(DM)患病率为5.2%,糖耐量减低(IGT)患病率为7.15%。原有DM人116人,新发现DM人145人,二者之比为1∶1.25。DM患病率山区各村>平原各村。IGT患病率山区各村>平原农村。DM及IGT患病率随年龄增加,体质量指数增加,血压增高,血脂异常而增高。结论未来糖尿病在农村特别是在山区有明显增加的趋势。     

生产工艺参数对奥美拉唑肠溶片释放度的影响

目的研究影响奥美拉唑肠溶片质量的生产工艺参数。方法用同一种包衣预混剂试验,分别考察肠溶衣层增重、包衣混悬液pH、包衣温度3个因素对奥美拉唑肠溶衣片释放度的影响。结果肠溶衣层增重越大,耐酸力越强,但同时会使释放度越小;包衣混悬液pH在一定范围内对释放度无影响;包衣温度过低出现粘片,包衣温度越高,耐酸力越弱,但同时会使释放度越大。结论当肠溶衣增重10.0%时,肠溶效果最理想;包衣液pH在6.0～7.2时,对肠溶效果影响小;包衣温度在36～39℃时,奥美拉唑肠溶片包衣操作较顺利,且释放度较好。     

PA-MSHA抗肿瘤效应的免疫机制研究

 目的  研究铜绿假单胞菌甘露糖敏感血凝菌毛株(pseudomonas aeruginosa mannose sensitive hemagglutinin,PA-MSHA)处理树突状细胞(dendritic cells,DCs)后对其功能及激活T细胞杀伤肿瘤细胞效应的影响。方法  取小鼠骨髓来源的DC,观察PA-MSHA体外处理后对DC表面分子、吞噬功能及T 细胞杀伤功能的影响。结果   PA-MSHA处理的DC其表面分子CD40、I-E表达显著上升,吞噬功能显著下降,由DC诱导的活化T细胞对肿瘤细胞的杀伤效应显著高于对照组。结论  PA-MSHA能有效促进DC成熟并增强抗肿瘤免疫效应。