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A novel split-gate SiC MOSFET with an embedded MOS-channel diode for enhanced third-quadrant and switching performances is proposed and studied using TCAD simulations in this paper. During the freewheeling period, the MOS-channel diode with a low potential barrier constrains the reverse current flow through it. Therefore, the suggested device not only has a low diode cut-in voltage but also entirely suppresses the intrinsic body diode, which will cause bipolar deterioration. In order to clarify the barrier-lowering effect of the MOS-channel diode, an analytical model is proposed. The calibrated simulation results demonstrate that the diode cut-in voltage of the proposed device is decreased from the conventional voltage of 2.7 V to 1.2 V. In addition, due to the split-gate structure, the gate-to-drain charge (QGD) of the proposed device is 20 nC/cm2, and the reverse-transfer capacitance (CGD) is 14 pF/cm2, which are lower than the QGD of 230 nC/cm2 and the CGD of 105 pF/cm2 for the conventional one. Therefore, a better high-frequency figure-of-merit and lower switching loss are obtained.

An enantioselective total synthesis of the alleged structure of (+)-fimbricalyxoid A is reported. The synthetic strategy features a pyridine

A three-step process for the enantioselective assembly of

Herein, we report a practical method for efficient asymmetric hydrogenation of β-aryl alkylidene malonates. With a site-specifically tailored chiral spiro iridium catalyst, a series of β-aryl alkylidene malonate esters were hydrogenated to afford chiral malonate esters with good to excellent enantioselectivities (up to 99% ee) and high turnover numbers (up to 19000). The results showed that installing an ester group in α,β-unsaturated carboxylic esters significantly increased the efficiency of their asymmetric hydrogenation reactions.

We have achieved the first concise, divergent, asymmetric total syntheses of mulinane diterpenoids. Specifically, we developed a new strategy featuring a key intramolecular Friedel-Crafts reaction to construct the chiral fused 5-6-6 tricyclic motif, followed by sequential Birch reduction, conjugate methylation, and homologation/ring-expansion reactions to furnish the desired 5-6-7 tricyclic skeleton bearing five contiguous stereocenters. With this efficient strategy, seven mulinane diterpenoids and two analogues were synthesized via late-stage functional modification or functionalization in 8.6-20% overall yields and 11-15 steps

Based on the achievement of 2.5 m/min casting speed on Shougang Jingtang (SGJT) No. 3 slab caster, effect of casting speed on the parameters closely related to the casting conditions was discussed elaborately by plant trial, mathematical simulation and experimental study respectively. The results showed that mold level fluctuation, surface velocity, average heat flux, bulging of broad face, temperature of copper plate, solidification crater end and frictional force entirely increased while the powder consumption rate, subsurface inclusions and depth of hook structure decreased with the increase of casting speed. As a consequence, flow control mold (FC mold) was more significant to control the mold level than submerged entry nozzle (SEN) and powder B was more appropriate for high speed casting than powder A. And further, it is highly recommended that high speed casting should be considered as a potential application to improve the surface quality of cold coils.

Objective To observe the clinical effect of tuina combine with needling distal points for pseudo-myopia in adolescents.

The UML model of database is a frame foundation of developing a database, this paper recommends a way to build data model based on the urban heating pipe networks by using VISIO[1] modeling tools. There are two ways that Use Case Diagram and Static Structure Diagram. The article describes the function of database application system, data structure and relationship on the heating-pipe network. The data structure model makes it more clear and lower redundancy when the developers are developing an application system of database.

A highly efficient iridium-catalyzed asymmetric hydrogenation of tetrasubstituted cyclic enones has been developed for the enantioselective synthesis of chiral cycloalkanols with three contiguous stereocenters. The C═O and C═C bonds of the enone substrates were hydrogenated sequentially in one pot with excellent enantioselectivity (92 to >99% ee) and diastereoselectivity (dr 95:5 to >99:1). The reaction provided a practical approach to all of the stereoisomers of the antiulcer drug rosaprostol.

In order to explore intrinsic relation of continuous, interlocked-dense and gap gradation, this paper studied them by fractal regression analysis, by which a gradation distribution Cartesian coordinate system was established and slope of the gradation was proposed at the same time. In addition, this study adopted gradation fractal Cartesian coordinate system to analysis the internal relations of continuous, interlocked-dense and gap gradation, at the same time verified and analyzed the correlation between the slope of the gradation and asphalt mixture gradation by using reference experimental data. The results show that: the gradation range given by specification can be approximated by a line segment, and the slope of the line can quantitatively reflect the relative thickness of coarse and fine aggregate of asphalt mixture; the gradation range given by specification possess a small proportion in the gradation fractal Cartesian coordinate system, which can be further optimized, and interlocked-dense asphalt mixture is a transitional form of continuous gradation and gap one; for the SAC asphalt mixture gradation, gradation slope has correlation with the formation of gradation skeleton; the Suitable fractal evaluation model for continuous, gap and interlocked-dense gradation was proposed finally. Thereby, the gradation fractal Cartesian coordinate system can not only reflect the relation of continuous, interlocked-dense and gap gradation, but also make it possible that the gradation distribution range in the specification can be expressed in function.

To explore the articles, authors and citations of the articles published in Chinese Journal of Pediatrics, and have a clear view of the characteristics of this journal in its different development stages.Bibliometric methods were used to analyze the published articles, cooperation, regional distribution, core authors, corresponding authors and high-quantities of publication institutes, and also to calculate the number of citations per paper, types of citations, language-based citation number, Price index, self-cited rate and the distribution of journals based on citations.Totally 5534 academic articles were published during the 60 years, of which the number of articles written by more than one author was 4669 (80.71%), with a degree of collaboration as 3.87, and a rate of collaboration as 84.37%. The number of articles by a single author was 865 (19.29%). As for the regions from where the papers were submitted, the top one was Beijing, which had 1495 articles published (27.01%). The top 15 institutes in number of articles had published 2254 articles (40.73%). The average citation rate was 84.15%, and the number of citations was 48 854. The number of citations per paper was 10.06, the Price index and self-cited rate were 55.57% and 6.12%, respectively. The number of citations from foreign language literature was 35 781 (69.1%). The citation number of journals was 43 266 (84.5%), which is markedly higher than the citations of books and others.Chinese Journal of Pediatrics has a wide distribution of authors and a high cooperative rate. This journal has a group of high-level core authors since founded in 1950, and it shows an adequate ability of absorbing and using scientific information. The articles published in this journal not only objectively reflected the distribution of the research powers, but also the development status of pediatrics in our country.

To explore, on the basis of principles of bibliometrics, the distribution of the authors of the articles published in Chinese Journal of Pediatrics, and the types of the institutions and the different regions from where the manuscripts were submitted in order to make a clear view of the characteristics and the status of cooperations in pediatric research work; to ascertain, among them, the core authors, core institutes and core regions; and to analyze the significance of corresponding authors, a new regulation adopted by this Journal in recent years, and to explore, furthermore, the funding status of the studies.Based on the information drawn from Chinese Medical Current Content (CMCC), bibliometric method was used to analyze the publications in Chinese Journal of Pediatrics and their authorship during the period from 1996 to 2005.Totally 3337 academic articles were published during the ten years; of which the number of articles written by more than one authors was 2951, accounting for 88.43 %, with a degree of collaboration as 4.12. The number of articles by a single author was 386 (11.57%). A total of 234 core authors contributed to 1031 research papers published (30.90% of all). As for the regions from where the papers were submitted, the top one was Beijing, which had 968 articles published (29% of all). And for the institutes, the number of the papers from the hospitals affiliated to medical schools was 2095 (62.78% of all), ranked the first. The second was research institutes which had 261 articles published in the Journal (7.82%), and 68 articles were from colleges and universities which ranked the third (2.03%). The top 10 institutes in number of papers had published 1273 articles (38.15% of all). The articles, from research projects funded by certain grants published in this Journal increased almost every year, from 7.44% of 1996 to 25.82% of 2005', which reflected timely and objectively a growing tendency in pediatric research and that funded research projects by certain garnts could be an important support to the publication of academic papers. The corresponding authorship as a signature regulation was introduced by this Journal in 1999, which played a positive role in pushing the leading work of key authors in construction of research groups. There were 2243 articles of pediatric clinical studies, (67.22%) and 1094 of basic research (32.78%).Chinese Journal of Pediatrics had a wide distribution of authors and a high cooperative rate. This Journal had a group of core authors who were strong in academy, active in research and productive in papers, and had a strong positive impact on this Journal. But it was also revealed that the research powers in the field of pediatric study were not evenly distributed. The guideline adopted by and for this Journal was clear and correct. The articles published in this Journal not only objectively reflected the distribution of the research powers and the latest achievements in pediatric study over the country, but also had its focus, which played a certain leading role in pediatric research.

The effects of liquid flow in mold and superheat on the formation of equiaxed zone in continuously cast low carbon steel slabs were discussed in present work. According to the fluid flow simulation results, “washing effect” was found out to bring about numerous equixed nuclei by detaching the dendrite arms at the solidification front in mold, and then the detached dendrites were remelted during sedimentation when the temperature in liquid pool was higher than remelting point. Based on the simulation results of liquid flow combining with the observation of equiaxed zone ratios and composition measurements varied with superheat, a formation mechanism of equiaxed zone was suggested for continuously cast slabs.