Experimental Study on Paschen Tests of ITER Current Lead Insulation

An experimental Paschen test setup has been established to analyze the quality of ITER current lead （CL） insulation and extend the research on Paschen＇s law under various conditions. Insulation problems can destroy a machine if a Paschen discharge is triggered by an insulation defect that is caused by faulty manufacturing, electromagnetic force, and thermal stress load with a certain degree of vacuum helium or pipe leakage. The results show that the CL insulation mock-up worked well under normal temperature and pressure. Besides, the mock-up also worked well in helium conditions and at 80 K temperature at different pressures. One area of CL insulation was severely destroyed when the 80 K test was conducted after 5 thermal cycles, resulting in Paschen discharge phenomenon. The breakdown voltage is maintained at a relatively low level under different pressure conditions; the change of breakdown voltage was mainly due to the change of pressure, and such change was in line with the Paschen law.

Reply to 'Statistical testing and distribution for lead chloride toxicity'

We are very grateful for the letter written by Dr Lange,and indeed apologize for the mistakes noted in the word-ing of our text regarding statistical analysis.This wasdue to changes carried out while revising the manuscriptat the request of reviewers,whom we thank for,point-ing out several issues that were actually similar to thosenoted by Dr.Lange.Unfortunately,we were unable todescribe and discuss our findings properly in the context

Revisiting the theoretical prediction of the explosive performance found by the Trauzl test

The Trauzl lead block test allows the determination of the approximate performance of explosives in blasting applications by measuring the volume increase(expansion)that is produced by the detonation of an explosive charge in the cavity of a lead block.In this paper,we reconsider the possibility of interpreting the Trauzl test results in terms of detonation parameters or quantities.The detonation parameters used in the analysis are calculated using the thermochemical code EXPLO5,while the hydrocode AUTODYN is used to simulate the effect of explosive charge density and reaction rate on the results of the Trauzl test.The increase in the volume of the lead block cavity was found to correlate best with the product of the detonation heat and the root of the volume of detonation products.Hydrocode simulation showed that the density of explosive charge and the rate of explosive decomposition affect the dynamics of the interaction of the detonation product and the lead block,and consequently the lead block cavity volume increase.

隔震装置阻尼机构的参数设计与振动台试验

为了改善浮放物体隔震装置中阻尼力的施加方式,研制出一款阻尼机构。对其构造和工作机理进行阐述,推导出了它的力学特征表达式,并验证了分析模型的准确性。结合某文物隔震装置的目标性能,利用数值方法对阻尼机构的参数进行设计,并对比振动台试验。结果表明:该阻尼机构结构简单,性能稳定;经阻尼参数优化后的隔震装置在满足位移限值的情况下达到了设定的隔震目标;试验与数值分析结果相吻合,证明了阻尼机构参数设计的正确性,同时也检验了隔震装置的安装和运行质量。其中,试验与数值分析结果的吻合程度,尤其是位移时程曲线的吻合程度,可为浮放物体隔震装置的方案对比和质量评估提供思路。

Failure Modes of Lead Free Solder Bumps Formed by Induction Spontaneous Heating Reflow

The shear failure modes and respective failure mechanism of Sn3.5Ag and Sn3.0Ag0.5Cu lead-free solder bumping on Au/Ni/Cu metallization formed by induction spontaneous heating reflow process have been investigated through the shear test after aging at 120℃ for 0, 1, 4, 9 and 16 d. Different typical shear failure behaviors have been found in the loading curves （shear force vs displacement）. From the results of interracial morphology analysis of the fracture surfaces and cross-sections, two main typical failure modes have been identified. The probabilities of the failure modes occurrence are inconsistent when the joints were aged for different times. The evolution of the brittle NiaSn4 and Cu-Ni-Au-Sn layers and the grains coarsening of the solder bulk are the basic reasons for the change of shear failure modes.

Wetting agent investigation for controlling dust of lead-zinc ores

The purpose of this project is to control the pollution of dust,which occurred in a typical lead-zinc mine.Two kinds of surfactants and water glass were chosen as the wetting agents to study the behaviours of suppressing the dust.The performances of the wetting agents of various sizes and water content of dust and their compositions among different weting agents were investigated. Firstly,the chemical compounds,dispersity,water content,bulk density and other relevant physico-chemical properties of the choiced dust of lead-zinc ore were mensurated.A great number of down-ward penetrating tests were conducted to different partical sizes of dust and to analyze the dust wetting behaviour respectively.The optimal compositions of wetting agents were obtained in accordance with different water contents and partical sizes of the dust after analyzing and statisting the achieved experimental data. The data show that the efficiency of chemical dust suppression of weting agents is much better than that of water.The results of the research work prove that the partical size and the water content of the dust are very important factors to the dust suppression.The results are also proved validly by the dropping experiment,which takes the penetrating diameter and penetrating time as the major factors.The superfine dust is much more difficult to be wetted.Since increasing the water content of dust is the best approach to control it,the choice of wetting agents for improving dispensation is significant.

铅芯隔震橡胶支座力学性能试验研究

针对铅芯隔震橡胶支座力学性能试验,重点分析橡胶支座结构及粘接试验标准,设计一种新型抗剪粘接模块化试验装置,与现有试验装置进行分析比对,对新型试验装置的结构进行分析计算,对LRB750、LRB900两种支座进行压缩性能、水平性能、水平非破坏粘接性能和破坏粘接性能试验,结果表明:试验设计满足要求,相比垂向压缩、水平剪切对隔震橡胶支座粘接性能影响更明显,且支座压缩刚度、屈服力、屈服刚度、水平等效刚度均满足要求,LRB900初始粘接破坏载荷761 kN、位移735 mm。该研究成果为橡胶支座及同类产品研发和试验提供一定指导作用。

Research on seismic performance and design method of combined steel lead energy dissipation structure(Ⅰ)

A new combined steel lead damper (NCSLD) was presented. Construction and working mechanism of NCSLD were introduced,pseudo-static tests of the small size dampers which would be used in the subsequent shaking table tests were carried out for the study of mechanical properties of NCSLD using electro-hydraulic servo press-shear machine. Processing technology of the damper was improved. Shaking table tests under two-dimensional excitation on structural aseismic control of a one-story structure model were carried out using the small size NCSLD; parameters of the structure and shaking table were also introduced. Results indicate that process improvement is beneficial to the implementation of working mechanism of the damper,NCSLD has full hysteresis loop which takes on bilinearity,NCSLD has obvious energy dissipation effect and it can control structural seismic response effectively.

铜铅混合精矿硫酸预氧化-浮选分离参数优化试验研究

方铅矿与黄铜矿的分离一直是选矿领域的难点,使用硫酸预氧化可选择性抑制方铅矿表面可浮性,使得两种矿物可浮性产生差异,实现浮选分离。针对铜铅混合精矿硫酸预氧化-浮选分离工艺进行了系统的参数优化。首先,利用单因素试验,分析了预氧化硫酸浓度、温度、时间等关键因素对铜铅混合精矿浮选分离效果的影响;其次,利用正交试验分析,建立了预氧化过程中各影响因素与浮选指标之间的数学模型;通过模型求解,得到最佳预氧化条件为硫酸浓度5 mol/L、时间40 min、温度100℃。最后在上述条件下进行了混合精矿预氧化-浮选闭路试验,获得了铜精矿Cu品位18.03%,Cu回收率94.52%;铅精矿Pb品位47.12%,Pb回收率为91.29%的良好指标,铜铅分离效果显著,对铜铅硫化混合精矿的浮选高效分离提供了一定的借鉴。

日用陶瓷制品镉迁移量在重复迁移试验中的变化

在前期开展的日用陶瓷制品多次4%乙酸迁移试验对铅迁移量的影响基础上,继续开展对镉迁移量的影响研究。试验以日常委托检测样品为对象,研究了连续三次迁移试验和间歇性多次迁移试验及长期迁移试验对镉迁移量的影响。试验结果表明:1)日用陶瓷制品镉迁移量在连续三次迁移试验中呈不断降低趋势;2)在间歇性多次迁移试验中间隔期对镉迁移结果有一定的影响,经过间隔期后的迁移量又有所回升;3)样品经历长期迁移试验后,后期镉析出能力跟样品的初始迁移量水平和制品的表面积S/浸泡液体积v有关。结合前期多次迁移试验对铅迁移量的影响研究结果和GB 31604.1-2015中的规定,日用陶瓷制品铅镉迁移量检测建议可采用一次迁移试验进行。

新建炼化装置的高压系统工程管理要点解析

高压系统主要由管道、管件、设备及仪表等组成,按照管道压力界定,指工作压力大于10 MPa、小于等于100 MPa的介质管道,在炼油化工行业主要应用于生产合成氨、尿素、甲醇产品和石油加氢裂化等领域。以组建生产能力为30万吨石蜡加氢装置为例,对建设此装置高压系统过程中所采用的施工技术和管理方法解析,包括材料采购与入场检验把关、材料到货管理、工艺细化、高压密封管理、焊接质量的严控及管道压力试验、泄漏性试验的管理等。通过采用上述管理方法和技术措施严格筛选出有质量问题的材料并及时进行修补、更换,保持了极高的焊接质量和高压密封质量,管道压力试验一次通过,项目按期中交,装置一次投产成功。实践证明此方法较为有效,可为类似项目建设提供实际参考。

平板运动试验与12导联动态心电图联合检查用于冠心病的诊断价值研究

目的分析平板运动试验与12导联动态心电图联合检查用于冠心病的诊断价值。方法选择本院2023年6月至2024年5月110例疑似冠心病患者为研究对象,所有患者均行平板运动试验及12导联动态心电图检查,以冠状动脉造影检查结果为“金标准”,比较2种方式单独检查及联合检查冠心病的诊断效能。结果“金标准”诊断结果显示,110例疑似患者中,阳性85例,阴性25例;平板运动试验显示,阳性89例,阴性21例;12导联动态心电图显示,阳性87例,阴性23例;二者联合检查显示,阳性84例,阴性26例;二者联合检查诊断冠心病的特异度96.00%、准确度97.27%、阳性预测值98.81%高于平板运动实验64.00%、87.27%、89.89%,高于12导联动态心电图72.00%、80.00%、91.95%(P<0.05);二者联合检查诊断冠心病误诊率4.00%低于平板运动实验36.00%,低于12导联动态心电图28.00%(P<0.05);冠状动脉造影结果显示,85例冠心病患者中单支病变20例,多支病变65例;平板运动实验、12导联动态心电图多支病变检出率98.5%、96.9%高于单支病变检出率80.0%、85.0%(P<0.05)。结论平板运动试验与12导联动态心电图联合检查诊断冠心病的价值高于单一检查,二者对冠心病的检出率随血管病变支数增加而增加。

河南某钼铅混合精矿分离试验研究

为高效利用河南某钼铅矿,针对其混合精矿钼铅分离困难、钼精矿中铅含量超标的问题,在对该混合精矿矿石性质研究的基础上,通过单因素条件试验,确定了分离粗选的关键技术参数,并采用正交试验法,以粗选水玻璃、DP-1和巯基乙酸钠用量作为自变量因素,选矿效率作为因变量因素,确定了钼铅分离的最佳抑制剂药剂制度。研究结果表明:当水玻璃用量3 kg/t、DP-1用量5kg/t、巯基乙酸钠用量18 kg/t时,选矿效率最优,并在此基础上进行1粗2扫7精闭路试验,最终获得了钼品位53.28%、含铅1.07%、钼回收率91.56%的钼精矿,实现了钼、铅的高效分离和回收。

地质样品银、铜、铅、锌测定过程中应用试液称重火焰原子吸收分光光度法的研究

本文应用试液称重火焰原子吸收分光光度法对地质样品银、铜、铅、锌元素进行测定。通过试验发现该方法不仅操作起来非常简便,而且测试速度快,所用试剂较少,试验操作不会对人员和环境造成伤害。另外,这一方法通过国家标准物质测定验证,获得的结果能够满足地质规范相关要求,在地质样品大批量测定过程当中可以推广应用。

煤矿许用乳化炸药作功能力试验研究

为了研究不同等级煤矿许用乳化炸药的作功能力以及其作功能力与安全等级的关系,分别采用铅壔法和弹道抛掷法对一级煤矿许用乳化炸药、二级煤矿许用乳化炸药及三级煤矿许用乳化炸药进行试验测试。测试结果表明,两种方法测得的三种等级煤矿许用乳化炸药作功能力均小于TNT炸药的作功能力。随着煤矿许用乳化炸药可燃气安全等级的上升,作功能力均有不同幅度的下降,其中三级煤矿许用乳化炸药作功能力下降得更多。铅壔法操作简单方便,不需要专门的仪器设备,极易普及;抛掷臼炮法具有试验药量大,测试结果平行误差小,具有良好的可靠性,可用于工业炸药的作功能力测试。

心电图平板运动试验在冠心病患者心肌缺血诊断中的应用

目的:探究12导联动态心电图(AECG)、平板运动试验(TET)应用于冠状动脉粥样硬化性心脏病(以下简称冠心病)患者心肌缺血中的诊断价值,为临床早期评估心肌缺血预后风险提供参考。方法:选取2021年5月—2022年8月南阳市第一人民医院收治的134例疑似心肌缺血的冠心病患者作为研究对象,以冠状动脉造影检查为金标准,分别进行AECG、TET检查,评估AECG、TET单独及联合检查对心肌缺血(冠脉狭窄≥50%)的诊断价值。结果:冠状动脉造影检查诊断出91例冠脉狭窄≥50%的心肌缺血患者,AECG检查+TET试验诊断出89例。AECG+TET检查诊断灵敏度、准确度及阴性预测值高于AECG、TET单独检查,漏诊率低于AECG、TET单独检查,差异有统计学意义(χ^(2)=11.107、8.795、7.546、8.795,P<0.05);根据AECG+TET检查诊断结果分为心肌缺血组、未心肌缺血组,心肌缺血组多支血管病变率高于未心肌缺血组,参考段血管径小于未心肌缺血组,直径狭窄率高于未心肌缺血组,差异有统计学意义(χ^(2)=5.909;t=2.541、3.350,P<0.05);AECG+TET检查诊断心肌缺血血管病变程度的符合率高于AECG、TET单独检查诊断,差异有统计学意义(χ^(2)=30.695,P<0.05)。结论:AECG+TET检查可有效提高冠心病患者心肌缺血诊断准确率,减少漏诊,明确血管病变程度,为临床早期针对性干预提供依据,改善患者预后。

水质检测中铅和镉方法检出限确定

辽宁省水环境监测中心使用火焰原子吸收法、石墨炉法分别对铅、镉的检出限进行测定。剔除离群值后,按全球环境监测系统水监测操作指南方法的检测方法计算火焰法原子吸收法铅、镉的检出限,以及石墨炉法原子吸收法铅、镉检出限。铅和镉方法检出限的确定为辽宁省水环境监测中心水质监测和资料整编工作提供了技术支撑。

粗化预电镀引线框架的可键合性研究

本文采用技术验证与统计学检验方法,使用自主研发的一款电镀粗镍用电化学沉积液,制备了粗化预电镀引线框架产品,并对产品可键合性能的影响因素进行了研究。研究结果表明,通过优化粗镍用电化学沉积液中的分散剂含量以及金层、钯层、镍层的厚度,可显著提升粗化预电镀引线框架的可键合性,制备出的粗化预电镀引线框架产品的键合性能完全满足行业内的应用要求,有望实现该类产品的国产化替代。

试样内置传感器密封引出装置设计与实现

针对岩石力学领域高温高压环境中内置传感器引出和保护问题,设计了一套传感器密封引出装置。该装置主要由垫块、限位座、压块、顶盖、套筒和环形卡箍等组成。验证试验结果表明,该装置实现了试样内部温度等参数的实时测量,保护了传感器及导线不受高温高压环境侵蚀,提高了大尺寸试样力学试验的稳定性及测试数据的准确性和可靠性。

公路工程中高填方路基质量病害问题探讨

高填方路基相比普通公路路基,具有更高的填方高度和较大的填方体积,因此其整体稳定性和施工质量控制难度较大。为了保证工程质量和提高施工效率,工程人员需要对高填方路基的各种质量问题进行综合分析,并制定合理的技术应用方案。本文将简要分析高填方路基常见的质量问题及相应的控制措施,并对高填方路基施工技术进行深入探讨,以供参考。