在准备本书第6版时，我想将一些对电力系统有较大影响的新内容介绍给大家，其中有以下5部分内容。 第13章、12.23～12.26节介绍了双馈感应电机的原理与特性。该电机的调速可通过在定子加固定频率交流电，而在转子通入可变频率交流电来实现，故名为“双馈”。双馈电机原来用作变速电动机来驱动大型水泵等负载，现在，该电机在风力发电中作为双馈发电动机使用。由于风力发电的重要性，有必要在本书中介绍这种特殊的电机。 第21章、21.45～21.51节对PWM的相关内容作了重要的修改，增加了新的内容及图片。 第23章介绍了几种电动机调速的电子控制方法。23.31～23.40节特别介绍了直接转矩控制（DTC）方法，与应用PWM及矢量控制方法不用，DTC使用了砰砰控制法，其对速度及转矩的控制与其他方法不同，该章根据感应电机原理，对此做了直观的分析。 第24章、24...(展开全部)

This best-selling book employs a theoretical, practical, multidisciplinary approach to provide introductory users with a broad understanding of modern electric power. The scope of the book reflects the rapid changes that have occurred in power technology over the past few years–allowing the entrance of power electronics into every facet of industrial drives, and expanding the f...(展开全部)

在准备本书第6版时，我想将一些对电力系统有较大影响的新内容介绍给大家，其中有以下5部分内容。 第13章、12.23～12.26节介绍了双馈感应电机的原理与特性。该电机的调速可通过在定子加固定频率交流电，而在转子通入可变频率交流电来实现，故名为“双馈”。双馈电机原来用作变速电动机来驱动大型水泵等负载，现在，该电机在风力发电中作为双馈发电动机使用。由于风力发电的重要性，有必要在本书中介绍这种特殊的电机。 第21章、21.45～21.51节对PWM的相关内容作了重要的修改，增加了新的内容及图片。 第23章介绍了几种电动机调速的电子控制方法。23.31～23.40节特别介绍了直接转矩控制（DTC）方法，与应用PWM及矢量控制方法不用，DTC使用了砰砰控制法，其对速度及转矩的控制与其他方法不同，该章根据感应电机原理，对此做了直观的分析。 第24章、24...(展开全部)

Science museums have paradoxes at their core. They must be accessible and fun while representing increasingly complex science. They must be both historic and contemporary. Their exhibits attract millions, but most of their objects remain in deep storage, seldom seen. This book delves into these conflicts, revealing the secret lives of science curators; where science objects com...(展开全部)

Science museums have paradoxes at their core. They must be accessible and fun while representing increasingly complex science. They must be both historic and contemporary. Their exhibits attract millions, but most of their objects remain in deep storage, seldom seen. This book delves into these conflicts, revealing the secret lives of science curators; where science objects com...(展开全部)

Virtual Machine technology applies the concept of virtualization to an entire machine, circumventing real machine compatibility constraints and hardware resource constraints to enable a higher degree of software portability and flexibility. Virtual machines are rapidly becoming an essential element in computer system design. They provide system security, flexibility, cross-plat...(展开全部)

Virtual Machine technology applies the concept of virtualization to an entire machine, circumventing real machine compatibility constraints and hardware resource constraints to enable a higher degree of software portability and flexibility. Virtual machines are rapidly becoming an essential element in computer system design. They provide system security, flexibility, cross-plat...(展开全部)

P．D．詹姆斯是英国当代最著名的推理小说女作家，被尊称为“推理小说第一夫人”。出生于1920年的P．D．詹姆斯自1950年开始写作，至今笔耕不辍。她已出版近20部作品，她的大部分作品均被拍成电视剧或电影。 P．D.詹姆斯的作品曾经多次获得英美推理小说奖。1987年荣获有“诺贝尔推理文学奖”之称的英国推理小说家协会“钻石匕首奖”终身成就奖，并受英国皇室勋封为女伯爵，1999年荣获美国推理小说家协会大师奖，也曾获爱伦坡奖。P.D.詹姆斯现任英国作家协会主席。

Neamen's Semiconductor Physics and Devices, Third Edition. deals with the electrical properties and characteristics of semiconductor materials and devices. The goal of this book is to bring together quantum mechanics, the quantum theory of solids, semiconductor material physics, and semiconductor device physics in a clear and understandable way.

For undergraduate-level courses in Signals and Systems. This comprehensive exploration of signals and systems develops continuous-time and discrete-time concepts/methods in parallel -- highlighting the similarities and differences -- and features introductory treatments of the applications of these basic methods in such areas as filtering, communication, sampling, discrete-tim...(展开全部)