Albert Einstein,who lived from 1879 to 1955,was the most-outstanding scientist of the twen-tieth oentury,He was a Jew born in Germany.He discovered the theory of relativity and de-
An intelligent power factor correction scheme is presented for three phase low power factor loads. This new scheme is able to perform individual phase sensing of parameters by monitoring at all times to sense a change...An intelligent power factor correction scheme is presented for three phase low power factor loads. This new scheme is able to perform individual phase sensing of parameters by monitoring at all times to sense a change in system parameters and affects individual phase correction by applying the exact amount of reactive components needed for each phase, and can also reduce negative sequence current caused by the load to improve system balance. An optimization criterion is used for the proper calculation of reactive power steps in a power compensation installation of capacitor banks. The criterion is enabled by sampling measurements performed on the electrical plant examined within specific interval of time.展开更多
随着天花板灯的调光控制要求越来越严格,单个传统模拟调光或PWM调光无法满足当前市场要求。但PWM与模拟调光的整合模式却是一个很好的选择。然而,由于寄生效应对MOS与输出二极管的结点电容器的影响,更深、更宽的调光仍然是一个挑战。还...随着天花板灯的调光控制要求越来越严格,单个传统模拟调光或PWM调光无法满足当前市场要求。但PWM与模拟调光的整合模式却是一个很好的选择。然而,由于寄生效应对MOS与输出二极管的结点电容器的影响,更深、更宽的调光仍然是一个挑战。还有一项挑战是满足LED输出电流与调光信号之间的良好线性规范要求。在本文中,我们将介绍基于U C C28810/11器件的模拟调光与PWM调光整合解决方案,以满足该规范要求。展开更多
文摘Albert Einstein,who lived from 1879 to 1955,was the most-outstanding scientist of the twen-tieth oentury,He was a Jew born in Germany.He discovered the theory of relativity and de-
文摘An intelligent power factor correction scheme is presented for three phase low power factor loads. This new scheme is able to perform individual phase sensing of parameters by monitoring at all times to sense a change in system parameters and affects individual phase correction by applying the exact amount of reactive components needed for each phase, and can also reduce negative sequence current caused by the load to improve system balance. An optimization criterion is used for the proper calculation of reactive power steps in a power compensation installation of capacitor banks. The criterion is enabled by sampling measurements performed on the electrical plant examined within specific interval of time.
文摘随着天花板灯的调光控制要求越来越严格,单个传统模拟调光或PWM调光无法满足当前市场要求。但PWM与模拟调光的整合模式却是一个很好的选择。然而,由于寄生效应对MOS与输出二极管的结点电容器的影响,更深、更宽的调光仍然是一个挑战。还有一项挑战是满足LED输出电流与调光信号之间的良好线性规范要求。在本文中,我们将介绍基于U C C28810/11器件的模拟调光与PWM调光整合解决方案,以满足该规范要求。
文摘背景：基线左心室重量增加可预测高血压的心血管并发症，但是高血压治疗期间，左心室重量降低与预后的关系尚未明确。
目的：确定抗高血压治疗期间，左心室重量降低是否能使主要心血管事件的危险性改善并独立于血压的变化。
设计、地点和参试者：于1995—2001年进行的氯沙坦干预降低高血压终点（Lasartan Intervention For Endpoint Reduction in Hypertension，LIFE）临床随机试验的前瞻性队列亚研究。LIFE试验共人选941例年龄55—80岁的原发性高血压且心电图提示左心室肥厚的患者。患者人选时接受超声心动图左心室重量测定，以后每年随访心血管事件，平均4．8±1．0年。
