This paper presents the design and fabrication of an effective, robust and process-tolerant floating guard ring termination on high voltage 4H-SiC PiN diodes. Different design factors were studied by numerical simulat...This paper presents the design and fabrication of an effective, robust and process-tolerant floating guard ring termination on high voltage 4H-SiC PiN diodes. Different design factors were studied by numerical simulations and evaluated by device fabrication and measurement. The device fabrication was based on a 12 μm thick drift layer with an N-type doping concentration of 8 × 10^15 cm^-3. P^＋ regions in the termination structure and anode layer were formed by multiple aluminum implantations. The fabricated devices present a highest breakdown voltage of 1.4 kV, which is higher than the simulated value. For the fabricated 15 diodes in one chip, all of them exceeded the breakdown voltage of 1 kV and six of them reached the desired breakdown value of 1.2 kV.展开更多
Male copulatory patterns, female multiple copulation and male post-copulatory guarding were studied in Eld＇s deer Cervus eldi in Datian National Nature Reserve, China. Mating behavior in 18 females and 11 males from ...Male copulatory patterns, female multiple copulation and male post-copulatory guarding were studied in Eld＇s deer Cervus eldi in Datian National Nature Reserve, China. Mating behavior in 18 females and 11 males from a group of 61 semi-captive Eld＇s deer were observed. The majority （55.8%） of copulations occurred between 15：00-19：00 h. The ejaculatory mount was preceded by an average of 5.1 prior mounts. Successful copulation consisted of a single thrust with ejaculation during one intromission, with no lock. This copulatory pattern is classified as pattern No. 15 （no lock, no intravaginal thrusting, single intromission, and multiple ejaculation） and No. 16 （no lock, no intravaginal thrusting, single intromission, and single ejaculation） under Dewsbury＇s scheme （1972） and as No. 16 （no lock, no thrusting, single and brief intromission） under Dixson＇s classification （1998）. Copulation frequency was 1.5 ± 0.9 times for males/females with the same female/male per day. The duration of the final mount, which included ejaculation, was brief （3.4±1.3 s）, and ejaculation usually terminated copulation. Eleven females copulated more than once in this study： three of them copulated with several males （multi-male copulations） and the remainder copulated with a single male （repeated copulations）. Our results indicate that some female Eld＇s deer may seek multiple copulations to be a strategy to improve the genetic quality of their offspring or to avoid harassment. Post-copulatory guarding of females by males followed all copulations, with dominant males guarding for significantly longer than subordinate males. Dominant males appear to be more effective at post-copulatory guarding than subordinate males. Subordinate males engaged in a quicker pre-copulatory phase to improve their chances of finishing copulation before being forced to accede to dominant males [Current Zoology 57 （3）： 284-292, 2011].展开更多
This site in the Peal River Delta abounds in unusual towers built for defense and as a refuge from natural disasters Jiangmen, in the Pearl River Delta in south China, is an enchanting city. Under its jurisdiction are...This site in the Peal River Delta abounds in unusual towers built for defense and as a refuge from natural disasters Jiangmen, in the Pearl River Delta in south China, is an enchanting city. Under its jurisdiction are Xinhui District and Taishan, Kaiping, Enping and Heshan cities, historically known as Wuyi (five counties) because of their shared popular customs.展开更多
In a hall of the Potala Palace, a treasure trove of Tibetan history and culture in Lhasa, capital of Tibet Autonomous Region in southwest China, a 7-meter high book shelf is stacked with priceless ancient documents, i...In a hall of the Potala Palace, a treasure trove of Tibetan history and culture in Lhasa, capital of Tibet Autonomous Region in southwest China, a 7-meter high book shelf is stacked with priceless ancient documents, including one written in the 17th century.展开更多
preyed upon not by strangers but people known to their family, says a report published by Protecting/ Girls, a charity project. The report covered sexual abuse cases published by the Chinese media from May 23, 2013 to...preyed upon not by strangers but people known to their family, says a report published by Protecting/ Girls, a charity project. The report covered sexual abuse cases published by the Chinese media from May 23, 2013 to May 22, 2014.展开更多
基金supported by the National High Technology Research and Development Program of China(No.2011AA050401)the Project of State Grid Corporation of China(No.SGRIDGKJ[2013]210)
文摘This paper presents the design and fabrication of an effective, robust and process-tolerant floating guard ring termination on high voltage 4H-SiC PiN diodes. Different design factors were studied by numerical simulations and evaluated by device fabrication and measurement. The device fabrication was based on a 12 μm thick drift layer with an N-type doping concentration of 8 × 10^15 cm^-3. P^＋ regions in the termination structure and anode layer were formed by multiple aluminum implantations. The fabricated devices present a highest breakdown voltage of 1.4 kV, which is higher than the simulated value. For the fabricated 15 diodes in one chip, all of them exceeded the breakdown voltage of 1 kV and six of them reached the desired breakdown value of 1.2 kV.
基金This research was supported by the Key Project in the National Science and Technology Pillar Program in the Eleventh Five-year Plan Period of China （Grant No. 2008BADBOB01）, and the National Natural Science Foundation of China （Grant No. 30770320）. We thank B. D. Bravery and Z.-Y. Jia for English editing and helpful comments on the manuscript, and we thank S.-Y. Li, Y.-Q. Wu, B. Long, E.-B. Zhang, H. Zhang and X. Wen of Datian National Nature Reserve for their assistance when we conducted fieldwork.
文摘Male copulatory patterns, female multiple copulation and male post-copulatory guarding were studied in Eld＇s deer Cervus eldi in Datian National Nature Reserve, China. Mating behavior in 18 females and 11 males from a group of 61 semi-captive Eld＇s deer were observed. The majority （55.8%） of copulations occurred between 15：00-19：00 h. The ejaculatory mount was preceded by an average of 5.1 prior mounts. Successful copulation consisted of a single thrust with ejaculation during one intromission, with no lock. This copulatory pattern is classified as pattern No. 15 （no lock, no intravaginal thrusting, single intromission, and multiple ejaculation） and No. 16 （no lock, no intravaginal thrusting, single intromission, and single ejaculation） under Dewsbury＇s scheme （1972） and as No. 16 （no lock, no thrusting, single and brief intromission） under Dixson＇s classification （1998）. Copulation frequency was 1.5 ± 0.9 times for males/females with the same female/male per day. The duration of the final mount, which included ejaculation, was brief （3.4±1.3 s）, and ejaculation usually terminated copulation. Eleven females copulated more than once in this study： three of them copulated with several males （multi-male copulations） and the remainder copulated with a single male （repeated copulations）. Our results indicate that some female Eld＇s deer may seek multiple copulations to be a strategy to improve the genetic quality of their offspring or to avoid harassment. Post-copulatory guarding of females by males followed all copulations, with dominant males guarding for significantly longer than subordinate males. Dominant males appear to be more effective at post-copulatory guarding than subordinate males. Subordinate males engaged in a quicker pre-copulatory phase to improve their chances of finishing copulation before being forced to accede to dominant males [Current Zoology 57 （3）： 284-292, 2011].
文摘This site in the Peal River Delta abounds in unusual towers built for defense and as a refuge from natural disasters Jiangmen, in the Pearl River Delta in south China, is an enchanting city. Under its jurisdiction are Xinhui District and Taishan, Kaiping, Enping and Heshan cities, historically known as Wuyi (five counties) because of their shared popular customs.
文摘In a hall of the Potala Palace, a treasure trove of Tibetan history and culture in Lhasa, capital of Tibet Autonomous Region in southwest China, a 7-meter high book shelf is stacked with priceless ancient documents, including one written in the 17th century.
文摘preyed upon not by strangers but people known to their family, says a report published by Protecting/ Girls, a charity project. The report covered sexual abuse cases published by the Chinese media from May 23, 2013 to May 22, 2014.
