基于电磁兼容的高速传输电连接器结构优化

针对目前高速传输电连接器插头电磁兼容性能较差的现状,提出了改进结构以增强其电磁兼容性能。结构改进为插头对接端增加屏蔽罩结构,并根据波导理论评估了当屏蔽罩对接端厚度h =0.28 cm 时,电连接器能增加38.5dB 的屏蔽效能。对改进前后的电连接器插头进行电磁场屏蔽效应仿真,仿真结果表明结构改进使屏蔽效能增加了21.9dB,验证了结构改进的可行性。对改进前和改进后的结构进行了静电抗扰度试验和电磁屏蔽试验,试验结果表明:结构改进前空气放电和接触放电引起的接触件两端电压分别为37.6 V、14.3 V,结构改进后空气放电和接触放电引起的接触件两端电压分别为4.8 V、3.3 V,结构改进后插头端面屏蔽效能为15.2dB。基于电磁兼容的高速传输电连接器结构优化为电连接器设计、电磁兼容性能升级提供了参考。     

Economic analysis of a diesel/photovoltaic hybrid system for decentralized power generation in northern Brazil

For small villages, hybrid options have advantages over traditional diesel systems because they reduce fuel consumption and O and M costs while improving the quality of service. Our cost analysis refers to a 20-year period at present market prices.     

高速传输电连接器差分阻抗优化

针对高速传输电连接器研发样机中存在差分阻抗偏小及不连续等问题,基于信号完整性理论提出了更换介质材料和修改接触件及介质尺寸的优化方案。采用HFSS高频电磁场仿真软件优化了接触件引脚直径W_1和引脚与介质体的配合长度L_1,仿真结果表明当引脚直径W_1=1.1 mm时,此时连接器差分阻抗仿真值为100±10Ω,且介质体配合长度L_1对连接器差分阻抗仿真值影响较小。对优化前后的连接器进行了样机加工及差分阻抗测试,测试结果表明改进前连接器差分阻抗范围为84.46~90.68Ω,改进后为92.6~105.3Ω,改进后的连接器差分传输眼图满足典型高速传输电连接器信号完整性传输要求。     

Medical diagnosis of rheumatoid arthritis disease from right and left hand Ulnar artery Doppler signals using adaptive network based fuzzy inference system (ANFIS) and MUSIC method

Rheumatoid arthritis (RA) is a multi-systemic autoimmune disease that leads to substantial morbidity and mortality. In this paper, as spectral analysis methods of Multiple Signal Classification (MUSIC) method is used in order to extract the significant features from the right and left hand Ulnar artery Doppler signals for the diagnosis of RA disease. The MUSIC method has been used as subspace method. To extract features from Doppler signals obtained from the right and left hand Ulnar arterial the MUSIC method model degrees of 5, 10, 15, 20, and 25 were used. Then, an adaptive network based fuzzy inference system (ANFIS) was applied to features extracted from the right and left hand Ulnar artery Doppler signals for classifying RA disease. The methods are not new, but the study has a novelty in that the application area of these methods is new. In the hybrid model, the combination of MUSIC and ANFIS yielded classification accuracies of 95% (for a model degree of 20) using the right hand Ulnar artery and classification accuracies of 91.25% (for a model degree of 10) using left hand Ulnar artery Doppler signals in the diagnosis of RA disease. The proposed approach has potential to help with the early diagnosis of RA disease for the specialists who study this subject.     

Process design and optimization of green processes for the production of hydrogen and urea from glycerol

To address the production of hydrogen and urea from glycerol, a green process of a glycerol-to-green chemicals chain (GTGC) named Scheme-1 is presented, where the glycerol is a green feedstock from the production of biodiesel and the carbon capture and utilization (CCU) is involved to reuse captured carbon. The major processes in the GTGC include that (i) the glycerol steam reforming (GSR), the water gas shift reactor, and the ammonia synthesis reactor are integrated to enhance the yields of hydrogen and ammonia, (ii) the pressure swing adsorption (PSA) is added to capture CO₂ and produce the high-purity hydrogen, and (iii) CO₂ is converted into urea by means of the urea synthesis reactor. The optimal operating conditions of GSR such as glycerol (GLY) conversion and cold gas efficiency are determined by using the response surface methodology. To address the lower CO₂ emissions of GTGC, the heat integration of GTGC named Scheme-2 and the heat integration/combined cycle power generation of GTGC named Scheme-3 are proposed. For the comparisons of total CO₂ emissions of the three schemes, Scheme-2 is lower than other schemes due to using the heat integration method for reducing hot/cold utilities. For the comparisons of net CO₂ emissions of the three schemes, Scheme-3 is superior to other schemes due to no use of external utilities.