A novel high step-down non-isolated DC-DC converter has been proposed. The proposed converter consists of highly efficient non-isolated cell converters using bidirectional semiconductor power devices, and these cell c...A novel high step-down non-isolated DC-DC converter has been proposed. The proposed converter consists of highly efficient non-isolated cell converters using bidirectional semiconductor power devices, and these cell converters are connected in ISOP （input series and output parallel）. The non-isolated ISOP converter achieves high step-down ratio of D/N, operating N cell converters under the duty ratio olD. Availability of the proposed converter has been shown by developing the 48 V-12 V laboratory prototype using two 24 V-12 V cell converters. Design consideration for the 48 V-3 V multicellular converter using four 12 V-3 V cell converters has been also conducted, and the potential to approach the efficiency of 97% has been discussed. The proposed topology is suitable for the POL （point of load） converters in the highly efficient next generation DC distribution system for data centers.展开更多
OBJECTIVE: To observe long-term functional recovery after contralateral C7 transfer. METHODS: From August 1986 to July 2000, 224 patients with brachial plexus avulsion injuries were treated with contralateral C7 trans...OBJECTIVE: To observe long-term functional recovery after contralateral C7 transfer. METHODS: From August 1986 to July 2000, 224 patients with brachial plexus avulsion injuries were treated with contralateral C7 transfer in our department. Thirty-two patients were followed up for over 2 years for evaluation of the following items: 1 influence on healthy limb function; 2 sensory and motor recovery of the recipient nerves in the affected limb; and 3 coordination between the healthy and affected limbs. RESULTS: There was no impairment of healthy limb function. Functional recovery of the recipient area reached > or =M3 in 8 patients (8/10, 80%) after musculocutaneous nerve neurotization, > or =M3 in 4 patients (4/6, 66%) after radial nerve neurotization, > or = M3 in 7 patients (7/14, 50%) and > or = M3 in 12 patients (85.7%) after median nerve neurotization, and > or = M3 in 1 patients (1/2, 50%) after thoracodorsal nerve neurotization. Synchronic contraction of the affected limb with the healthy limb occurred within 2-3 years in 12 patients, within 5 years in 13 patients, and over 5 years in 7 patients. CONCLUSION: Contralateral C7 transfer is an ideal procedure for the treatment of brachial plexus root avulsion injury. Selection of the whole root or the posterior division as neurotizer and a staged operation are the major factors influencing treatment outcome.展开更多
作为挖掘装载机的发明看，凯斯日前向中国市场隆重推出全新的凯斯M2系列挖掘装载机。M2系列包括580IV、580 Turbo、580 Super M和590 Super M四个型号，发动机功率80～103 ho，这四个型号全部采用全新的完全符合Tier Ⅱ排放标准的凯斯...作为挖掘装载机的发明看，凯斯日前向中国市场隆重推出全新的凯斯M2系列挖掘装载机。M2系列包括580IV、580 Turbo、580 Super M和590 Super M四个型号，发动机功率80～103 ho，这四个型号全部采用全新的完全符合Tier Ⅱ排放标准的凯斯新代发动机。M2系列是凯斯具有创新、耐用和高效传统的挖掘装载机家庭中最新的成员。展开更多
文摘A novel high step-down non-isolated DC-DC converter has been proposed. The proposed converter consists of highly efficient non-isolated cell converters using bidirectional semiconductor power devices, and these cell converters are connected in ISOP （input series and output parallel）. The non-isolated ISOP converter achieves high step-down ratio of D/N, operating N cell converters under the duty ratio olD. Availability of the proposed converter has been shown by developing the 48 V-12 V laboratory prototype using two 24 V-12 V cell converters. Design consideration for the 48 V-3 V multicellular converter using four 12 V-3 V cell converters has been also conducted, and the potential to approach the efficiency of 97% has been discussed. The proposed topology is suitable for the POL （point of load） converters in the highly efficient next generation DC distribution system for data centers.
文摘OBJECTIVE: To observe long-term functional recovery after contralateral C7 transfer. METHODS: From August 1986 to July 2000, 224 patients with brachial plexus avulsion injuries were treated with contralateral C7 transfer in our department. Thirty-two patients were followed up for over 2 years for evaluation of the following items: 1 influence on healthy limb function; 2 sensory and motor recovery of the recipient nerves in the affected limb; and 3 coordination between the healthy and affected limbs. RESULTS: There was no impairment of healthy limb function. Functional recovery of the recipient area reached > or =M3 in 8 patients (8/10, 80%) after musculocutaneous nerve neurotization, > or =M3 in 4 patients (4/6, 66%) after radial nerve neurotization, > or = M3 in 7 patients (7/14, 50%) and > or = M3 in 12 patients (85.7%) after median nerve neurotization, and > or = M3 in 1 patients (1/2, 50%) after thoracodorsal nerve neurotization. Synchronic contraction of the affected limb with the healthy limb occurred within 2-3 years in 12 patients, within 5 years in 13 patients, and over 5 years in 7 patients. CONCLUSION: Contralateral C7 transfer is an ideal procedure for the treatment of brachial plexus root avulsion injury. Selection of the whole root or the posterior division as neurotizer and a staged operation are the major factors influencing treatment outcome.
文摘作为挖掘装载机的发明看，凯斯日前向中国市场隆重推出全新的凯斯M2系列挖掘装载机。M2系列包括580IV、580 Turbo、580 Super M和590 Super M四个型号，发动机功率80～103 ho，这四个型号全部采用全新的完全符合Tier Ⅱ排放标准的凯斯新代发动机。M2系列是凯斯具有创新、耐用和高效传统的挖掘装载机家庭中最新的成员。
