强对流云新概念在积云人工增雨作业中的运用

在对强对流(积云)增雨作业中,引用防雹新概念方法是利用多普勒雷达不同仰角的反射率(R)图及反射率剖面(RCS)图、径向速度剖面(VCS)图等资料,对强对流云流场特征进行定性分析,判定其主位置,通过主入流区位置和态势,确定“0”线的类型,给出增雨作业的时机和部位。用这一新概念,结合天津地区积云增雨的实际情况,在2003~2005年期间进行了应用。当流场、温度场和水凝物粒子场适当配置时,会形成大量降水粒子的集中累积,产生阵性暴雨。

Bipolar Theory of MOS Field-Effect Transistors and Experiments

The bipolar theory of field-effect transistor is introduced to replace the 55-year-old classic unipolar theory invented by Shockley in 1952 in order to account for the characteristics observed in recent double-gate nanometer silicon MOS field-effect transistors. Two electron and two hole surface channels are simultaneously present in all channel current ranges. Output and transfer characteristics are computed over practical base and gate oxide thicknesses. The bipolar theory corroborates well with experimental data reported recently for FinFETs with metal/silicon and p/n junction source/drain contacts. Single-device realization of CMOS inverter and SRAM memory circuit functions are recognized.

The Bipolar Field-Effect Transistor:Ⅰ.Electrochemical Current Theory(Two-MOS-Gates on Pure-Base)

This paper describes the bipolar field-effect transistor （BiFET） and its theory. Analytical solution is ob- tained from partitioning the two-dimensional transistor into two one-dimensional transistors. The analysis employs the parametric surface-electric-potential and the electrochemical （quasi-Fermi） potential-gradient driving force to compute the current. Output and transfer D. C. current and conductance versus voltage are presented over practi- cal ranges of terminal D. C. voltages and device parameters. Electron and hole surface channel currents are pres- ent simultaneously, a new feature which could provide circuit functions in one physical transistor such as the CMOS inverter and SRAM memory.

The Bipolar Field-Effect Transistor: III.Short Channel Electrochemical Current Theory (Two-MOS-Gates on Pure-Base)

This paper describes the short channel theory of the bipolar field-effect transistor （BiFET） by partitioning the transistor into two sections,the source and drain sections,each can operate as the electron or hole emitter or collector under specific combinations of applied terminal voltages. Analytical solution is obtained in the source and drain sections by separating the two-dimensional trap-free Shockley Equations into two one-dimensional equations parametrically coupled via the surface-electric-potential and by using electron current continuity and hole current continuity at the boundary between the emitter and collector sections. Total and electron-hole-channel components of the output and transfer currents and conductances, and the electrical lengths of the two sections are computed and presented in graphs as a function of the D. C. terminal voltages for the model transistor with two identical and connected metal-oxide-silicon-gates （MOS-gates） on a thin pure-silicon base over practical ranges of thicknesses of the silicon base and gate oxide. Deviations of the long physical channel currents and conductances from those of the short electrical channels are reported.

The Bipolar Field-Effect Transistor:Ⅳ.Short Channel Drift-Diffusion Current Theory(Two-MOS-Gates on Pure-Base)

This paper gives the short channel analytical theory of the bipolar field-effect transistor （BiFET） with the drift and diffusion currents separately computed in the analytical theory. As in the last-month paper which represented the drift and diffusion current by the single electrochemical （potential-gradient） current, the two-dimensional transistor is partitioned into two sections, the source and drain sections, each can operate as the electron or hole emitter or collector under specific combinations of applied terminal voltages. Analytical solution is then obtained in the source and drain sections by separating the two-dimensional trap-free Shockley Equations into two one-dimensional equations parametrically coupled via the surface-electric-potential and by using electron current continuity and hole current continuity at the boundary between the emitter and collector sections. Total and the drift and diffusion components of the electron-channel and hole-channel currents and output and transfer conductances, and the electrical lengths of the two sections are computed and presented in graphs as a function of the D. C. terminal voltages for the model transistor with two identical and connected metal-oxide-silicon-gates （MOS-gates） on a thin pure-silicon base over practical ranges of thicknesses of the silicon base and gate oxide. Deviations of the two-section short-channel theory from the one-section long-channel theory are described.

The Bipolar Field-Effect Transistor:II.Drift-Diffusion Current Theory(Two-MOS-Gates on Pure-Base)

This paper describes the drift-diffusion theory of the bipolar field-effect transistor （BiFET） with two identical and connected metal-oxide-silicon-gates （MOS-gates） on a thin-pure-base. Analytical solution is obtained by partitioning the two-dimensional transistor into two one-dimensional problems coupled by the parametric sur- face-electric-potential. Total and component output and transfer currents and conductances versus D. C. voltages from the drift-diffusion theory, and their deviations from the electrochemical （quasi-Fermi） potential-gradient theory,are presented over practical ranges of thicknesses of the silicon base and gate oxide. A substantial contri- bution from the longitudinal gradient of the square of the transverse electric field is shown.

The Theory of Field-Effect Transistors:XI. The Bipolar Electrochemical Currents(1-2-MOS-Gates on Thin-Thick Pure-Impure Base)

The field-effect transistor is inherently bipolar, having simultaneously electron and hole surface and volume channels and currents. The channels and currents are controlled by one or more externally applied transverse electric fields. It has been known as the unipolar field-effect transistor for 55-years since Shockley＇s 1952 invention,because the electron-current theory inevitably neglected the hole current from over-specified internal and boundary conditions, such as the electrical neutrality and the constant hole-electrochemical-potential, resulting in erroneous solutions of the internal and terminal electrical characteristics from the electron channel current alone, which are in gross error when the neglected hole current becomes comparable to the electron current, both in subthreshold and strong inversion. This report presents the general theory, that includes both electron and hole channels and currents. The rectangular （ x, y, z） parallelepiped transistors,uniform in the width direction （z-axis）,with one or two MOS gates on thin and thick,and pure and impure base, are used to illustrate the two-dimensional effects and the correct internal and boundary conditions for the electric and the electron and hole electrochemical potentials. Complete analytical equations of the DC current-voltage characteristics of four common MOS transistor structures are derived without over-specification： the 1-gate on semi-infinite-thick impure-base （the traditional bulk transistor）, the 1-gate on thin impure-silicon layer over oxide-insulated silicon bulk （SOI） ,the 1-gate on thin impure-silicon layer deposited on insulating glass （SOI TFT）, and the 2-gates on thin pure-base （FinFETs）.

A Blowdown Cryogenic Cavitation Tunnel and CFD Treatment for Flow Visualization around a Foil

Cavitation is one of the major problems in the development of rocket engines. There have been few experimental studies to visualize cryogenic foil cavitation. Therefore a new cryogenic cavitation tunnel of blowdown type was built. The foil shape is “piano-convex”. This profile was chosen because of simplicity, but also of being similar to the one for a rocket inducer impeller. Working fluids were water at room temperature, hot water and liquid nitrogen. In case of Angle of Attack （AOA）=8°, periodical cavity departure was observed in the experiments of both water at 90℃ and nitrogen at -190℃ under the same velocity 10 m/sec and the same cavitation number 0.7. The frequencies were observed to be 110 and 90 Hz, respectively, and almost coincided with those of vortex shedding from the foil. Temperature depression due to the thermodynamic effect was confirmed in both experiment and simulation especially in the cryogenic cavitation.

Impact of 〈100〉Channel Direction for High Mobility p-MOSFETs on Biaxial Strained Silicon

Biaxial strain technology is a promising way to improve the mobility of both electrons and holes, while （100） channel direction appears as to be an effective booster of hole mobility in particular. In this work, the impact of biaxial strain together with （100） channel orientation on hole mobility is explored. The biaxial strain was incorporated by the growth of a relaxed SiGe buffer layer,serving as the template for depositing a Si layer in a state of biaxial tensile strain. The channel orientation was implemented with a 45^o rotated design in the device layout,which changed the channel direction from （110） to （100） on Si （001） surface. The maximum hole mobility is enhanced by 30% due to the change of channel direction from （110） to （100） on the same strained Si （s-Si） p-MOSFETs,in addition to the mobility enhancement of 130% when comparing s-Si pMOS to bulk Si pMOS both along （110） channels. Discussion and analysis are presented about the origin of the mobility enhancement by channel orientation along with biaxial strain in this work.

Clinical observation on acupuncture treatment for constipation due to intestinal qi stagnation

Objective： To compare the different therapeutic effects of acupuncture and Phenolphthalein for constipation due to intestinal qi stagnation. Methods： A total of 50 patients with constipation due to intestinal qi stagnation were randomly divided into an acupuncture group and a medication group by the random digital table, 25 cases in each group. The patients in the acupuncture group were treated by puncturing Gongsun（SP 4）, Sanyinjiao（SP 6）, Taichong（LR 3）, Zusanli（ST 36）, Shangjuxu（ST 37）, Hegu（LI 4）, Lieque（LU 7）, and Tianshu（ST 25）, once every day, and 7 d as one course, for continuous 3 courses; while the patients in the medication group were given Phenolphthalein, 7 d as one course, for continuous 3 courses. Compared the Cleveland clinic constipation score（CCS） between the two groups after one course, 3 courses and 3 months after the treatment, as well as the frequency of defecation within one week. Results： After one week of treatment, CCS scores and frequency of defecation per week were significantly changed in both groups compared with those before treatment（P〈0.05）, and CCS scores and frequency of defecation per week were improved more significantly in the patients of the medication group than in those of the acupuncture group（P〈0.01）. After 3 weeks of treatment, CCS scores and frequency of defecation per week were significantly changed in both groups compared with those before treatment（P〈0.05）, and CCS scores and frequency of defecation per week were improved more significant in the patients of the acupuncture group than in those of the medication group（P〈0.05）. Three months after the end of treatment, CCS scores and frequency of defecation per week were significantly changed in both groups compared with those before treatment（P〈0.05）, and CCS scores and frequency of defecation per week were improved more significantly in the patients of the acupuncture group than in those of the medication group（P〈0.05）. Conclusion： Acupuncture and medication are effective in the treatment of constipation due to intestinal qi stagnation. Their short-term therapeutic effect is similar, but the long-term therapeutic effect is better in the acupuncture group than in the medication group.