Hydrogen Transportation Behaviour of V–Ni Solid Solution: A First-Principles Investigation

Hydrogen embrittlement causes deterioration of materials used in metal–hydrogen systems. Alloying is a good option for overcoming this issue. In the present work, first-principles calculations were performed to systematically study the effects of adding Ni on the stability, dissolution, trapping, and diffusion behaviour of interstitial/vacancy H atoms of pure V. The results of lattice dynamics and solution energy analyses showed that the V–Ni solid solutions are dynamically and thermodynamically stable, and adding Ni to pure V can reduce the structural stability of various VH_x phases and enhance their resistance to H embrittlement. H atoms preferentially occupy the characteristic tetrahedral interstitial site (TIS) and the octahedral interstitial site (OIS), which are composed by different metal atoms, and rapidly diffuse along both the energetically favourable TIS → TIS and OIS → OIS paths. The trapping energy of monovacancy H atoms revealed that Ni addition could help minimise the H trapping ability of the vacancies and suppress the retention of H in V. Monovacancy defects block the diffusion of H atoms more than the interstitials, as determined from the calculated H-diffusion barrier energy data, whereas Ni doping contributes negligibly toward improving the H-diffusion coefficient.     

两种口腔镍铬合金离子析出的体外实验研究

目的 研究Heraenium S与TILITE P两种口腔镍铬合金在唾液pH值和成分变化时离子析出行为。方法 将两种合金试件在pH6墙正常唾液环境中浸泡一周，再用pH4的酸性及酸性加0．1％F^-的人工唾液处理两小时，之后回到正常唾液环境中浸泡一周，观察其在处理前、后镍离子的析出和表面理化状态的改变。结果 ①在正常唾液环境中HeraeniumS合金镍离子的析出量大于TILITEP合金；②pH降低和氟化物的加入增大了两种合金镍离子的析出量，其中TILITEP合金大于HeraeniumS合金；③在短暂的pH降低和加入氟化物后再回到正常唾液环境中，TILITEP合金的镍离子析出量大于HeraeniumS合金；并且在合金表面可以观察到形态学上的腐蚀破坏。结论 口腔镍铬合金的镍离子析出受到口腔环境动态变化的影响，TILITEP合金对环境改变的敏感性曼大。     

Morphometrical analysis of cleaning capacity of a hybrid instrumentation in mesial flattened root canals

The cleaning capacity of hybrid and rotary instrumentation techniques in mesial flattened canals of mandibular first molars was evaluated by morphometrical analysis in this study. Twenty human mandibular first molars were randomly assigned into two groups, according to instrumentation technique, as follows: group 1, instrumentation with ProTaper Starter Kit (Dentsply/Maillefer) rotary system; group 2, manual instrumentation using K files (Dentsply/Maillefer) by crown-down technique in middle and apical thirds, cervical preparation with Gates-Glidden #1 and #2 (Dentsply/Maillefer) burs, and to finalise the preparation, ProTaper F2 and F3 rotary files. Serial transverse cross-sections (5 μm) of the apical third, stained with hematoxylin and eosin, were analysed at 100× original magnification. The images were submitted to morphometrical analysis with an integration grid to determine the percentage of root canal area with debris. Statiscal analysis (t-Student, P < 0.05) showed significant difference between the techniques (P < 0.05), although neither completely cleaned the root canal.     

The Effects of Grain Boundary Misorientation on the Mechanical Properties and Mechanism of Plastic Deformation of Ni/Ni3Al: A Molecular Dynamics Study

The effects of grain boundary misorientation angle (θ) on mechanical properties and the mechanism of plastic deformation of the Ni/Ni₃Al interface under tensile loading were investigated using molecular dynamics simulations. The results show that the space lattice arrangement at the interface is dependent on grain boundary misorientations, while the interfacial energy is dependent on the arrangement. The interfacial energy varies in a W pattern as the grain boundary misorientation increases from 0° to 90°. Specifically, the interfacial energy first decreases and then increases in both segments of 0–60° and 60–90°. The yield strength, elastic modulus, and mean flow stress decrease as the interfacial energy increases. The mechanism of plastic deformation varies as the grain boundary misorientation angle (θ) increases from 0° to 90°. When θ = 0°, the microscopic plastic deformation mechanisms of the Ni and Ni₃Al layers are both dominated by stacking faults induced by Shockley dislocations. When θ = 30°, 60°, and 80°, the mechanisms of plastic deformation of the Ni and Ni₃Al layers are the decomposition of stacking faults into twin grain boundaries caused by extended dislocations and the proliferation of stacking faults, respectively. When θ = 90°, the mechanisms of plastic deformation of both the Ni and Ni₃Al layers are dominated by twinning area growth resulting from extended dislocations.     

复方尼阿措提取物对高脂血症大鼠的调血脂作用

目的:探讨复方尼阿措提取物(CNAE)的调血脂作用。方法:通过灌胃脂肪乳剂制备实验性高脂血症大鼠模型。随机分为正常对照组、模型对照组、阳性对照组(1 mL.kg-1)、柳茶水提物(SAE)低、高剂量组(6.01,2.0 g.kg-1)、CNAE低、高剂量组(8.0,16.0 g.kg-1)。除正常组外,各给药组大鼠灌胃给予脂肪乳剂,基础饲料喂养,末次给药后,腹主动脉采血测定血清总胆固醇(TC)、甘油三脂(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)和丙二醛(MDA)的含量及超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性。结果:CNAE能明显降低TC、TG、LDL-C和MDA含量(P<0.01),升高HDL-C浓度,显著提高SOD及GSH-Px酶活性(P<0.01),且降血脂作用优于SAE。结论:CNAE具有明显的调血脂和抗氧化作用,提示其可用于高脂血症的防治。     

反复熔铸镍铬合金在腐蚀液中的镍离子析出

背景：重复熔铸镍铬烤瓷合金是否会加大镍离子的析出,从而降低抗腐蚀性能,研究结论不一。 目的：检测非真空状态下反复熔铸镍铬烤瓷合金在人工唾液中镍离子的析出量,分析熔铸次数对合金抗腐蚀性能的影响。 方法：非真空状态下反复熔铸镍铬烤瓷合金Ⅰ、Ⅱ、Ⅲ、Ⅳ代,将试件浸泡于按照ISO标准制定的pH值为6.8,4.0的人工唾液中(168±1) h,恒温(37±1) ℃,利用Z-5000原子吸收分光光度计检测不同pH值人工唾液中镍离子的析出量。 结果与结论：相同pH值状态下,经两两比较发现,4代Ni-Cr烤瓷合金差异均有显著性意义(P < 0.05),铸造第Ⅳ代镍离子析出最多,其次为Ⅲ代、Ⅱ代。随pH值的降低,合金的抗腐蚀性能降低,镍离子析出增多。提示非真空条件下反复熔铸镍铬烤瓷合金的耐腐蚀性能下降,随着熔铸次数的增加,镍离子的析出明显增多。     

Bending Fatigue Behaviour and Fatigue Endurance Limit Prediction of 20Cr2Ni4A Gear Steel after the Ultrasonic Surface Rolling Process

To study the effect of the surface properties on the bending fatigue performance of heavy-duty gear steel, the authors of this paper used the ultrasonic surface rolling process (USRP) to strengthen 20Cr2Ni4A carburized gear steel. USRP is a novel technique in which the ultrasonic technology is incorporated into the concept of conventional deep rolling. In this study, we illustrated how the surface properties and cross-section mechanical property influence the three-point bending fatigue life of the samples before and after USRP treatment. At the same time, the predicted failure probability-stress-number of cycles (P-S-N) curve was drawn, and the fatigue fracture was analysed. The results show that the fatigue limit increased from 651.36 MPa to 918.88 MPa after USRP treatment. The fatigue source is mainly from the sample interior or surface scratches, and the fatigue performance is positively correlated with the results of the material surface roughness, surface residual stress and surface hardness. At the same time, combined with the change in the phase structure, dislocation structure, residual stress and hardness of the cross section of the material, it is found that the USRP process turns the steel into a gradient material with five layers. Finally, the coupling mechanism between the ultrasonic surface strengthening deformation layer and the carburized layer of 20Cr2Ni4A carburized gear steel is presented, and the grain structure distribution diagram of the section of the 20Cr2Ni4A model after surface strengthening treatment was simulated. The mechanism that influenced the fatigue performance after USRP treatment is explained from the perspectives of the surface and cross section of the samples.     

Econlith2000震波碎石系统脉冲通路撞击片制作及替用

通过对Econlith2000震波碎石系统脉冲通路金属撞击片的原理、功能解析及其化学成分和金相组织的分析,在各种不锈钢材料的机械、物理性能的比较中,找到一种可替代原来撞击片材料的1Cr17Ni7,制作并替用。取代原来的进口产品,获得较好的经济效益。     

梅毒螺旋体Tp0453和TpN47抗原的制备及应用

目的表达纯化梅毒螺旋体Tp0453和TpN47蛋白,评价2种蛋白的检测效果,并建立一种新的梅毒抗体检测方法。方法以梅毒螺旋体Nichols菌株基因组DNA为模板,通过PCR扩增Tp0453和TpN47蛋白基因,构建原核表达载体;转化表达菌株后经IPTG诱导表达,并优化表达条件,大规模培养后采用Ni2+亲和柱纯化目的蛋白;纯化蛋白用过碘酸钠法进行HRP标记,采用双抗原夹心ELISA法分别评价两种蛋白的检测效果,在此基础上,按比例混合两种抗原,并建立双抗原夹心ELISA检测法。结果构建了Tp0453和TpN47蛋白的原核表达载体,在低温(27℃)和低剂量IPTG(0.1mmol/L)诱导条件下,有效的实现了Tp0453和TpN47蛋白的可溶性表达。采用Ni2+亲和纯化方法成功纯化出了高纯度的Tp0453和TpN47融合蛋白,ELISA检测结果显示Tp0453比TpN47具有更强的反应性,两种蛋白混合,建立的双抗原夹心ELISA检测法通过血清学试验表明具有很好的敏感度和特异性。结论实现了梅毒螺旋体Tp0453和TpN47蛋白快速高效的表达,并结合2种抗原优势,建立了一种高效的梅毒双抗原夹心ELISA检测方法。     

Effect of Annealing Process on the Properties of Ni(55%)Cr(40%)Si(5%) Thin-Film Resistors

Resistors in integrated circuits (ICs) are implemented using diffused methods fabricated in the base and emitter regions of bipolar transistor or in source/drain regions of CMOS. Deposition of thin films on the wafer surface is another choice to fabricate the thin-film resistors in ICs’ applications. In this study, Ni(55%)Cr(40%)Si(5%) (abbreviated as NiCrSi) in wt % was used as the target and the sputtering method was used to deposit the thin-film resistors on Al₂O₃ substrates. NiCrSi thin-film resistors with different thicknesses of 30.8 nm~334.7 nm were obtained by controlling deposition time. After deposition, the thin-film resistors were annealed at 400 °C under different durations in N₂ atmosphere using the rapid thermal annealing (RTA) process. The sheet resistance of NiCrSi thin-film resistors was measured using the four-point-probe method from 25 °C to 125 °C, then the temperature coefficient of resistance could be obtained. We aim to show that resistivity of NiCrSi thin-film resistors decreased with increasing deposition time (thickness) and the annealing process had apparent effect on the sheet resistance and temperature coefficient of resistance. We also aim to show that the annealed NiCrSi thin-film resistors had a low temperature coefficient of resistance (TCR) between 0 ppm/°C and +50 ppm/°C.