触头感应钎焊钎着率的研究

针对接触器触头的感应钎焊，研究了感应钎焊温度及钎焊间隙对钎着率的影响。找出了感应钎焊温度及钎焊间隙对钎着率的影响规律。研究表明钎焊温度、钎焊间隙的最佳配合是获得高钎着率的重要条件。     

Summarization on variable liquid thrust rocket engines

The technology actuality and development trend of variable thrust rocket engines at home and abroad are summarized. Key technologies of developing variable thrust rocket engines are analyzed. Development advices on developing variable thrust rocket engines that are adapted to the situation of our country are brought forward.     

Monaural Speech Separation Using Dual-Output Deep Neural Network with Multiple Joint Constraint

Monaural speech separation is a significant research field in speech signal processing. To achieve a better separation performance, we propose three novel joint-constraint loss functions and a multiple joint-constraint loss function for monaural speech separation based on dual-output deep neural network(DNN). The multiple joint-constraint loss function for DNN separation model not only restricts the ideal ratio mask(IRM) errors of the two outputs, but also constrains the relationship of the esti...     

On the tension necking of copper single crystal specimen under slip deformation mechanism

The tension necking of FCC copper single crystal specimen with a square cross section was analyzed under the slip deformation mechanism. The actual clamp manner of the specimen was modeled by setting correlative boundary condition,and the small angle deflection between tension loading axis and crystallography axis [100] was taken into account. The finite deformation numerical analysis of three-dimensional necking deformation for the specimen was performed by apply-ing crystal plasticity theory associated with a numerical algorithm suggested by the first author. According to the comparison with experimental observation,the fact was confirmed that the numerical results could describe the loading elongation curve of the copper single crystal specimen under large strain tension reasonably,and the method could be used to investigate the necking characteristic in neck shape and the effect due to the small angle deflection. Further,the investigation into the influence of specimen cross-section shape on necking was also performed;the results on mechanical response and neck profile evolution obtained through modeling of cylindrical specimen were compared with those obtained with square cross-section specimen.     

Noise Analysis of Analog Correlator

A noise model for the analog correlator used in the ultra wideband receivers is proposed due to lack of simulation capability on noise performance of the correlator in current EDA tools.The analog correlator circuit is divided into several parts to calculate the equivalent noise sources respectively.The ideal impulse generators,instead of the noise sources,are then applied to obtain the time varying transfer functions.Fourier transforms are carried out to explore the relationship between the noise input and output in frequency domain for each part.Then the symmetrical noise sources are grouped together and the periodicity of the circuit is utilized to further simplify the model.This model can be used to evaluate noise performance of the correlator.     

对食管电极起搏位置与心房起搏阈值关系的探讨

目的探讨食管电极起搏位置与心房起搏阈值关系。方法对125例无器质性心脏病的患者,进行食管心房调搏(TEAP)检查,分别于心房上区、心房区、心房下区测量心房起搏阈值,然后对检查结果对比分析。结果心房起搏阈值在11～25V范围内,3个部位(心房上区、心房区、心房下区)有效起搏率分别为35.20%(44/125)、97.60%(122/125)与96.00%(120/125);但副作用发生率心房上区(咳嗽68.80%)与心房下区(膈肌痉挛26.40%)明显高于心房区(分别为8.00%与0.00%)。结论心房起搏阈值与食管电极起搏位置明显相关,食管心房调搏时食管电极的位置以心房区最优。     

提高PLC性能的精密信号处理和数据转换IC

可编程逻辑控制器(PLC)是一种基于计算机的紧凑电子系统,该系统使用数字或模拟输入和输出模块控制机械、处理器和其它的控制模块.     

CHP发动机用不同压缩比的生物甲烷和引燃燃料的双燃料试验（英文）

使用生物甲烷作为气体燃料,使用加热油和各种生物燃料作为引燃燃料,测试了来自相同柴油机的两种不同的双燃料配置.结果表明,相比压缩比为19∶1的"柔性双燃料模式",压缩比为16∶1的"引燃模式"有更高的生物甲烷比率,在小载荷下电效率值较低,在中载荷下两者相同,在高负载时电效率值较高.该两种模式均可实现超过42%的电效率及大约1的功率系数,这证明了所研究的CHP发动机台架具有良好的热效率与电效率.     

Reticular exploration of uranium-based metal-organic frameworks with hexacarboxylate building units

The rational reticular design of metal-organic frameworks(MOFs)from building units of known geometries is essential for enriching the diversity of MOF structures.Unexpected and intriguing structures,however,can also arise from subtle changes in the rigidity/length of organic linkers and/or synthetic conditions.Herein,we report three uranium-based MOF structures—i.e.,NU-135X(X=0,1,2)—synthesized from trigonal planar uranyl nodes and triptycene-based hexacarboxylate ligands with variable arm lengths.A new chiral 3,6-connected nuc net was observed in NU-1350,while the extended versions of the ligand led to 3-fold catenated MOFs(NU-1351 and NU-1352)with rare 3,6-connected cml-c3 nets.The differences in the topology of NU-1350 and NU-1351/NU-1352 could be attributed to the slight distortions of the shorter linker in the former from the ideal trigonal prism geometry to an octahedral geometry when coordinated to the trigonal planar uranyl nodes.     

Heat dissipation in graphene foams

Graphene foam(GF)—a three-dimensional network of hollow graphene branches—is a highly attractive material for diverse applications.However,to date,the heat dissipation characteristics of GFs have not been characterized.To fill this gap,we synthesized GF devices,subjected them to high temperatures,and investigated their thermal behavior by using infrared microthermography.We find that while the convective area of GF devices is comparable to that of bulk materials(such as metals),the coefficient of convection of these devices is several orders of magnitude higher than that of metals.In addition,the GF devices showed a reproducible thermal behavior,which we attribute to negligible temperature-induced morphological changes(as confirmed by Raman analysis).Taken together,our findings suggest GF as a promising candidate material for advanced cooling applications where efficient heat dissipation is needed,e.g.,in electrical circuits.