Protel99SE仿真中一个常见问题的分析——共射极放大器为什么不反相了?

因为共射极放大器的输出电压与输入电压在相位上相差180°,共射极放大器也称反相器。初学者在用Protel99SE进行电路仿真分析时,经常会出现不反相的现象,这是一个让初学者困惑的问题。本文通过对这一现象的深入分析,提出用Protel99SE仿真时应特别注意的问题,供初学者参考。     

Semi-submersible wind turbine hull shape design for a favorable system response behavior

Floating offshore wind turbines are a novel technology, which has reached, with the first wind farm in operation, an advanced state of development. The question of how floating wind systems can be optimized to operate smoothly in harsh wind and wave conditions is the subject of the present work. An integrated optimization was conducted, where the hull shape of a semi-submersible, as well as the wind turbine controller were varied with the goal of finding a cost-efficient design, which does not respond to wind and wave excitations, resulting in small structural fatigue and extreme loads.The optimum design was found to have a remarkably low tower-base fatigue load response and small rotor fore-aft amplitudes. Further investigations showed that the reason for the good dynamic behavior is a particularly favorable response to first-order wave loads: The floating wind turbine rotates in pitch-direction about a point close to the rotor hub and the rotor fore-aft motion is almost unaffected by the wave excitation. As a result, the power production and the blade loads are not influenced by the waves. A comparable effect was so far known for Tension Leg Platforms but not for semi-submersible wind turbines. The methodology builds on a low-order simulation model, coupled to a parametric panel code model, a detailed viscous drag model and an individually tuned blade pitch controller. The results are confirmed by the higher-fidelity model FAST. A new indicator to express the optimal behavior through a single design criterion has been developed.     

基于Protel 99SE的电路仿真运用技术

采用电路设计仿真工具对电路的设计理念和输出进行仿真验证是提高设计质量、降低研制成本、缩短研制周期的有效手段.但如果模型运用不当或参数设置不合适,也会对仿真结果造成较大的失真,影响产品的设计质量.本文以目前较为流行的Protel 99SE电子线路辅助设计仿真工具软件为例,通过几个案例深入分析Protel 99SE电路仿真的应用技术.     

~(99m)Tc-Sb_2S_3胶体颈部淋巴显像及其临床评价

采用~（99m）Tc-Sb_2S_3胶体,对13例正常人及31例口腔颌面部恶性肿瘤患者进行了颈部淋巴显像。探讨了颈部淋巴显像的技术和方法,并将显像结果与淋巴结病理学检查对照研究。本方法具有安全、简便、病人无痛苦,且可重复等优点。应用其判定口腔颌面部恶性肿瘤淋巴转移的灵敏度为90.9％,特异性为80.0％,准确率为83.9％,是有一定诊断价值的检查方法。     

航空蓄电池充电机控制电路的Protel仿真

针对航空蓄电池充电机性能检测、故障诊断难度大的问题,在对其控制电路工作原理分析的基础上,采用Protel 99 SE对其触发电路和电流调节电路进行了仿真。仿真结果与理论分析相符,证明了理论分析的正确性。通过改变相关元器件参数,分析仿真波形的变化,为该充电机控制电路的检测和故障诊断提供重要依据,并为其故障树的建立奠定了基础。     

Protel 99 SE在电路设计中的应用技巧

本文详细介绍了Protel 99 SE在电路设计中非常重要的几个技巧,在电路设计中应用这些技巧会给电路的设计带来很大的方便,并且可以在电路设计中减少错误。本文用实例进行了分析说明。     

Protel99在电子工程技术应用领域中的实用技巧

Protel99具有三维电路板浏览、全局编辑、自动生成元件列表、通用可编程逻辑器件设计等强大功能，本文介绍了以上功能的实现方法和应用中的技巧。     

BVAC.N99型真空断路器替代TDZ1型空气断路器电气接口改进方案

针对现有电力机车TDZ1型空气断路器升级换代为BVAC.N99型真空断路器项目中电气接口不兼容的问题,分析其形成的原因,并提出了解决措施。     

Classification decision tree algorithm assisting in diagnosing solitary pulmonary nodule by SPECT/CT fusion imaging

Objective To develop a classification tree algorithm to improve diagnostic performances of 99mTc-MIBI SPECT/CT fusion imaging in differentiating solitary pulmonary nodules (SPNs). Methods Forty-four SPNs, including 30 malignant cases and 14 benign ones that were eventually pathologically identified, were included in this prospective study. All patients received 99Tcm-MIBI SPECT/CT scanning at an early stage and a delayed stage before operation. Thirty predictor variables, including 11 clinical variables, 4 variables of emission and 15 variables of transmission information from SPECT/CT scanning, were analyzed independently by the classification tree algorithm and radiological residents. Diagnostic rules were demonstrated in tree-topology, and diagnostic performances were compared with Area under Curve (AUC) of Receiver Operating Characteristic Curve (ROC). Results A classification decision tree with lowest relative cost of 0.340 was developed for 99Tcm-MIBI SPECT/CT scanning in which the value of Target/Normal region of 99Tcm-MIBI uptake in the delayed stage and in the early stage, age, cough and specula sign were five most important contributors. The sensitivity and specificity were 93.33% and 78. 57e, respectively, a little higher than those of the expert. The sensitivity and specificity by residents of Grade one were 76.67% and 28.57%, respectively, and AUC of CART and expert was 0.886±0.055 and 0.829±0.062, respectively, and the corresponding AUC of residents was 0.566±0.092. Comparisons of AUCs suggest that performance of CART was similar to that of expert (P=0.204), but greater than that of residents (P<0.001). Conclusion Our data mining technique using classification decision tree has a much higher accuracy than residents. It suggests that the application of this algorithm will significantly improve the diagnostic performance of residents.