基于元件测试的端接技术在LCR测试仪中的研究

简述了LCR测量仪的测量原理,研究了LCR测试仪中元件测试的几种端接技术的特点、误差及阻抗适用范围。每种端接技术的连接方法各有优缺点,必须根据被测元（DUT）的阻抗和要求的测量精度,选择合适的连接方法。     

化学镀镍和镍/金在微电子领域中的应用及展望

介绍了化学镀镍和镍／金技术以及镍-磷层的电学性能，综述了其在倒装芯片凸焊点的UBM、印刷电路板和电感-电容-电阻LCR元件生产上的应用。展望了化学镀镍技术在微电子领域中的应用前景。     

Lacoste—Romberg（G）型重力仪格值公式

本文根据Lacoste-Romberg(G)型重力仪(简称LCR(G)型重力仪)读数系统的结构特征,首次导出了LCR(G)型重力仪的相对重力公式和格值公式。并根据文[3]中提供的格值表,用本文导出的公式进行最小二乘曲线拟合,得到有关参数,利用所求参数计算了相应的格值,与文[3]中提供的格值符合得很好。     

用MT4090 LCR测量仪检测水泥砂浆裂缝的试验研究

以预设不同尺度裂缝的水泥砂浆块体和无裂缝水泥砂浆块体等三组试件为试验研究对象,提出利用MT4090 LCR测量仪直接测试试件的复阻抗幅模在z和相角φ、等效串联电阻ESR和电容Cs ,并与基于交流阻抗谱法得到的测试数据进行比较。试验研究表明：基于交流阻抗谱法和用MT4090 LCR测量仪得到的数据非常接近,具有同样的规律和特征;有裂缝的水泥砂浆试件的z 、ESR值明显大于无裂缝水泥砂浆试件,且随裂缝长度增大而增大,Cs值变化规律相反,这3个参数可以作为裂缝检测及监测的测试参数;用MT4090 LCR测量仪有望真正实现快速、简便的混凝土裂缝的检测与实时监测;验证了水泥砂浆试件呈现电容性,且容抗值相对ESR值较小。     

Asymptotic stabilization and synchronization of parametric LCR resonant circuit using the characteristics of its coefficients

In this paper, we analyze stability of a time‐varying system represented by second‐order vector differential equations based on the characteristics of their coefficient matrices. New sufficient conditions for asymptotic stability of the equilibrium points are derived. Then, an asymptotic stabilizing control method of parametric LCR resonant system is discussed by using the obtained sufficient conditions. A method synchronizing two parametric LCR resonant systems is also given. The effectiveness of the results is illustrated by numerical examples. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(3): 48–55, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20142     

Accelerated thermal fatigue of lead-free solder joints as a function of reflow cooling rate

Leadless chip resistor (LCR) assemblies were manufactured using both traditional tin-lead (Sn37Pb) and lead-free (Sn3.8Ag0.7Cu) solders. The leadfree test vehicles were assembled using three different cooling rates: 1.6°C/sec, 3.8°C/sec, and 6.8°C/sec. They were then exposed to accelerated thermalcycling (ATC) tests between 0°C and 100°C with a 10–14°C/min ramp rate and a 5-min dwell time. The test results indicated that these lead-free solder joints had better creep-fatigue performance than the tin-lead solder joints. The LCR built with the medium cooling rate showed the longest fatigue life compared with the resistors built with the normal cooling rate of 1.6°C/sec and the higher cooling rate 6.8°C/sec. The number of cycles to failure was significantly correlated to the void defect rate. Failure analyses were done using cross-sectioning methods and scanning electron microscopy (SEM). Finite-element models were built to analyze the inelastic, equivalent strain range in solder joints subjected to thermal-cycling conditions with different degrees of solder wetting. The results indicated that poor wetting increases strains throughout the joint significantly, which is in accordance with the ATC results.     

马尾松KP浆和桉木KP浆混合浆打浆工艺研究

以未漂马尾松KP浆和桉木KP浆混合浆生产纸袋纸,研究了纸袋纸高浓打浆（HcR）、低浓打浆（LcR）和高浓打浆后接着低浓打浆工艺。结果表明,马尾松KP浆配加一定比例的桉木KP浆。用低浓打浆成纸可获得较好的抗张和耐破强度;用高浓打浆成纸可获得较好的伸长率、撕裂度和透气度;用高浓后接着低浓打浆成纸性能可兼顾高低浓打浆的优点。随着桉木浆配比增加,纸袋纸的抗张、伸长、TEA、撕裂、耐破和透气性能指标整体下降。     

基于分段正弦信号激发的LCR波应力检测的研究

根据临界折射纵波(LCR波)的产生原理及其应力检测原理,提出采用分段正弦信号来激发LCR波,并运用互相关时延估计实现应力检测。分段正弦信号激发LCR波,相对于脉冲信号激发,能在较低的电压幅值下获得足够的发射能量。同时,分段正弦信号激发产生的LCR波在介质中传播时,波形畸变小,便于实现高精度的数据处理。实验结果表明,该方法能有效的测量出试件的内部应力。     

矢量网络分析仪的时间门功能在吸波材料性能测试中的应用

在利用低频同轴反射法(LCR)进行材料吸波性能的测试过程中,经常会使用矢量网络分析仪的GATE功能来滤除干扰因素对测试结果的影响。本文通过对测试原理的阐述和不同吸波材料的测试结果的分析,说明了如何合理地设置矢量网络分析仪的GATE以及测试过程中应该注意的问题。     

液芯压下技术在CSP生产线连铸扇形段的应用

阐述武钢CSP连铸机液芯压下扇形段的构成、控制原理、功能作用,介绍武钢CSP连铸液芯压下技术(LCR)的应用实践、常见故障及处理措施,并指出连铸液芯压下技术的进一步开发应用方向。