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Some circuits use resonant, quasi-resonant, and/or multi-resonant techniques. However, voltage or current stresses in these converters are higher and require the devices of higher VA rating. Some circuits use passive snubbers or active clamp techniques. However these converters become more complicate. Phase-shift ZVS technique has been used in bidirectional DC/DC converters since it can realize ZVS for all switches without auxiliary switches.

谐振、准谐振或多谐振技术方案，变换器的电压电流应力较高，变频控制增加了滤波器设计的难度；能量缓冲吸收电路或有源钳位电路方案，由于需要增加多个额外辅助元件，增加了变换器的复杂性；全桥相移技术方案，由于主电路无需增加额外元件，只需利用相移控制，即可实现软开关，因此引起关注。

The main products are: DC contacts, relays, exchanges and contacts, thermal overload relays, time relay, vacuum-assisted switches, auxiliary switch, switch universal, direct, circuit breakers and other exchanges. CZY1 series of contacts which DC Patent No.

主要产品有：直流接触器、继电器，交流接触器，热过载继电器，时间继电器，真空辅助开关，辅助开关，万能转换开关，直、交流断路器等。

In this paper, with the Buck circuit topology as the exampleof zero-transition soft-switching PWM DC/DC converters, theoperation principle and characteristics of the conventionalZVT-PWM converter and a novel two phase ZVT-PWM converter areanalyzed in-depth respectively.

文中以Buck型电路拓扑作为研究零过渡PWM软开关DC／DC变换器的代表，分别对传统ZVT-PWM变换器和一种新型的两相ZVT-PWM变换器的工作原理及特性进行了深入的分析。

An injection type shunt hybrid active power filter was analyzed, it can suppress harmonic currents and compensate high capacity reactive power, nevertheless, a sharp boosting on DC-side voltage was found in application. Based on the analyses of the reasons, different solutions was proposed such as adoption of main circuit of multiple performances, the use of hysteretic control method, fore-feed control of reflowing current or direct control on DC-side voltage without a rectifier to supply.

研究一种兼具大容量无功补偿能力的注入式并联混合有源滤波器，并分析其在工程应用中发现的直流侧电压抬升现象及这种现象产生的原因，在此基础上提出从采用多重化主电路结构、滞环控制法、回灌电流前馈控制法和脱离整流电源直接对直流侧电压进行控制等几个方面来抑制直流侧电压抬升的方法。

Part III: Peripheral blood dendritic cells in coronary atheroscleroticdiseaseObjectives: Dendritic cells subsets, Myeloid DC and plasmacytoid DC, regulate immune reactions by polarising naive T-helper cells into a Th1 or Th2 response, respectively.

第三部分：冠心病患者外周血树突状细胞亚型的变化的研究目的：树突状细胞的两个亚型，髓样DC和浆细胞样DC分别是促使T辅助细胞向Th1和Th2免疫应答转化的抗原呈递细胞。

This research adopts the impedance marching method, by varying duty cycle in a DC-DC converter to make the apparent load impedance matching with current system impedance, and reach the mpp operation.

控制电路的部分由单晶片PIC18F452为中心，重点为如何有效的取得太阳电池的开路电压及短路电流，以便正确计算出太阳电池的内部阻抗。

This research improves the impedance marching method, by varying duty cycle in a DC-DC converter to make the apparent load impedance matching with current system impedance, and reach the mpp operation.

本论文是改善阻抗匹配法，使其在不同照度下皆能准确做最大功率点追踪，并且应用阻抗匹配法在实际的太阳光能发电系统，经由调整DC-DC转换器中的主动开关之责任周期来达到负载与太阳能板的匹配，达成最大功率传输。

The major products for the cable pressure, machine, cable-hot machine, cable dryer, cable tester comprehensive testing, AC-DC pressure tester, vacuum switch vacuum tester, DC high-voltage generators, fire-retardant heat-tape, such as Die Equipment and accessories, complete specifications, performance good, reasonable price and abide by the contract, implementation of Three Guarantees, the agency checked.

产品主要为电缆压号机、电缆热补机、电缆干燥机、电缆综合探伤测试仪、交直流耐压测试仪、真空开关真空度测试仪、直流高压发生器、阻燃热补胶带、模具等设备及其配件，规格齐全，性能良好，价格合理，信守合同，实行三包，代办托运。

Companies rely on some of Xi'an University of Electronic Science and Technology professor, research institutes of technology support, long-term cooperation in research and development power automation, electrical testing, electrical testing equipment, including: Switching mechanical properties tester, vacuum tester, cable fault tester, cable test Management systems, cables altimeter instrument, relay calibrator, DC high-voltage generator, or flow, test transformers, DC Resistance Tester, loop resistance tester, and change than the group tester, MOA tester, Transformer test aircraft, dielectric loss tester, ground resistance tester, such as electric Zhaoou table.

公司依托西安电子科技大学部分教授，科研院所的科技支持，长期合作研发电力自动化、电力测试、电气试验仪器设备，包括：开关机械特性测试仪、真空度测试仪、电缆故障测试仪、电缆测试管理系统、电缆测高仪、继电保护校验仪、直流高压发生器、升流器、试验变压器、直流电阻测试仪、回路电阻测试仪、变比组别测试仪、氧化锌避雷器测试仪、变压器试油机、介质损耗测试仪、接地电阻测试仪、电动兆欧表等。

The DC-Pulse power supply can be separated into two parts. One is the DC power supply and the other is the pulse switch unit.

此直流脉冲电源供应器可分为二部分，一为直流电源供应器部分，另一为脉冲切换单元部分。

This matter overthrew all basises I learned from Sunday school .

这件事把我从周日学校学到的所有道理都颠覆了。

It's one of the cruel ironies of aging: if you want to remember your favorite restaurants, the less you should eat at them.

这是一个老化的残酷讽刺：如果你想记住你最喜欢的餐馆，你应该更少吃到它们。