Numerical and Experimental Study of Localized Lifetime Control LIGBT by High Dose He Ion Implantation

A high speed LIGBT with localized lifetime control by using high dose and low en ergy helium implantation(LC-LIGBT) is proposed.Compared with conventional LIGB Ts,particle irradiation results show that trade-off relationship between turn- off time and forward voltage drop is improved.At the same time,the forward volta ge drop and turn-off time of such device are researched,when localized lifetime control region place near the p+-n junction,even in p+ anode.The results s how for the first time,helium ions,which stop in the p+ anode,also contribute to the forward voltage drop increasing and turn-off time reducing.

Diurnal Variation of Tropical Cyclone Rainfall in the Western North Pacific in 2008-2010

Diurnal variation of tropical cyclone （TC rainfall in the western North Pacific （WNP） is investi gated using the high-resolution Climate Prediction Ce~ ter＇s morphing technique （CMORPH） products obtaine from the National Oceanic and Atmospheric Administra tion （NOAA）. From January 2008 to October 2010, 7 TCs and 389 TC rainfall days were reported by the Joir Typhoon Warning Center＇s （JTWC） best-track record. Th TC rain rate was partitioned using the Objective Synopti Analysis Technique （OSAT） and interpolated into Local Standard Time （LST）. Harmonic analysis was applied t analyze the diurnal variation of the precipitation. Obviou diurnal cycles were seen in approximately 70% of the TC rainfall days. The harmonic amplitude and phase of the mean TC rainfall rate vary with TC intensity, life stage, season, and spatial distribution. On the basis of intensity, tropical de- pressions （TDs） exhibit the highest precipitation variation amplitude （PVA）, at approximately 30%, while super ty- phoons （STs） contain the lowest PVA, at less than 22%. On the basis of lifetime stage, the PVA in the decaying stage （more than 37%） is stronger than that in the devel oping （less than 20%） and sustaining （28%） stages. On the basis of location, the PVA of more than 35% （less than 18%） is the highest （lowest） over the high-latitude oceanic areas （the eastern ocean of the Philippine Islands）. In ad dition, a sub-diurnal cycle of TC rainfall occurs over the high-latitude oceans. On the basis of season, the diurnal variation is more pronounced during summer and winter, at approximately 30% and 32%, respectively, and is weaker in spring and autumn, at approximately 22% and 24%, respectively.

Mobility in the Retirement Period An Assessment of the Current Situation

Today, individuals＇ attitudes towards retirement and old age have changed with the increase of life expectancy and healthy and active years after retirement, rise in purchasing power, and mobility opportunities. As a result of this change, the rate of post-retirement migration, settling into a new life in a new region after retirement, has considerably increased. However, despite of this increase, post-retirement migration is one of the least analyzed migration movements among existing studies. Hence, in this article, studies analyzing properties of post-retirement migration and factors causing this migration are assessed. As every migration movement, post-migration movements also create changes laying different responsibilities on both emigrant and immigrant regions and migrating person and require settling into a new life in the place of arrival. In the relevant studies, the basic reason for post-retirement migration is considered as pursuit of peace and joy and it is defined as a migration type under the high influence of counter-urbanization movement. According to the results of the study, it is stated that post-retirement migrants, unlike many international migrants, can buy their own houses in the countries of arrival and can maintain a relatively high standard of living compared to that local community, and that this situation is a very attractive factor encouraging them to migrate. Moreover in the studies, characteristics causing migration and belonging to the region of departure are analyzed as aversive while characteristics belonging to the region of arrival are analyzed as attractive factors.

2018年高考作文题要突出“写思辨”

2018年高考作文题降低了考生思维品质的考查强度。今后高考作文命题要减少命题中'命意'成分,增加'命域'比例;要把'面'命题与'点'命题结合好;要适当增加对立、比照、甚至带有一点负面性质的概念、事件及事理,以达成让考生在真实情境中辩证辨析概念,在多维度的比较中较好的说理论证的效果。

On orders in number fields: Picard groups, ring class fields and applications

We focus on orders in arbitrary number fields, consider their Picard groups and finally obtain ring class fields corresponding to them. The Galois group of the ring class field is isomorphic to the Picard group.As an application, we give criteria of the integral solvability of the diophantine equation p = x2+ ny2 over a class of imaginary quadratic fields where p is a prime element.

Transition of Quaternary glacial cyclicity in deep-sea records at Nansha,the South China Sea

High-resolution oxygen isotope records over the last 2249 ka (MIS 1-86) have been obtained from cores of the upper section (105.08 m) at ODP Site 1143 (water depth of 2772 m)drilled in the Nansha area, southern South China Sea. The sampling resolution is at about 2 ka intervals, resulting in one of the best oxygen isotope records over the global ocean. The oxygen isotope curves, displaying details in the Pleistocene glacial cycles, have revealed a nearly 300 ka long stage of transition from a predominant 40 ka to 100 ka periodicity. Therefore, the 'Mid-Pleistocene Revolution' should be considered as a process of transition rather than an abrupt change. Within the 100 ka glacial cycles, the changes in tropical sea surface water were found to lead those in high-latitude ice sheet. Our comparisons show that the ice sheet expansion and the glacial stage extension in the Northern Hemisphere with the 100 ka cycles must have been driven not by ice sheet itself, but by processes outside the high latitudes of the Northern Hemisphere.

Artificial enzymes,cancer chemotherapy,conjugation and nanoelectronics,and prebiotic chemistry

This is a summary,with extensive references,of several areas of chemistry in which the Breslow lab has been involved,leading to work still underway in several of them.The principal conclusions are described,but it will be necessary to consult the references for details of the work involved.