检索结果-南通市图书馆

Proportional rate scheduling based on QoS in mobile WiMAX networks

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2009年第6期20卷 1332-1335页

作者： Fang Lintang zhang Xiaolin School of Electronic and Information Engineering Beihang Univ. Beijing 100191 P. R. China

A new scheduling scheme based on users＇ quality of service（QoS） in mobile WiMAX networks is *** proposed scheme tracks each user＇s average rate and adjusts the corresponding scheduling weight adaptively to result in：（a） each user＇s average rate is proportional to the corresponding QoS level;（b） the constraints of the minimal and/or maximal rates required by QoS can be satisfied;（c） the utility function of system is maximal under the constraints（a） and（b）.Theoretical analysis based on utility function and simulation results indicates the system throughput can be improved dramatically in the proposed scheme.

关键词： mobile WiMAX quality-of-service scheduling utility function.

Cytochrome P450 monooxygenase-mediated eicosanoid pathway:A potential mechanistic linkage between dietary fatty acid consumption and colon cancer risk

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2019年第4期8卷 337-343页

作者： Weicang Wang Jianan zhang guodong zhang Department of Food Science University of Massachusetts-AmherstAmherstMA01003USA Molecular and Cellular Biology Program University of Massachusetts-AmherstAmherstMA01003USA

Human consumption of linoleic acid(LA,18:2ω-6,abundant in vegetable oils)is very *** experiments showed that excessive LA intake increased azoxymethane-induced colon tumorigenesis,however,the impact of excessive LA on colon cancer in human is not conclusive,making it difficult to make dietary recommendations for optimal intake of *** the molecular mechanisms of LA on colon tumorigenesis could help to clarify its health effect,and facilitate development of mechanismbased strategies for preventing colon *** studies show that the previously unappreciated cytochrome P450 monooxygenase-mediated eicosanoid pathway is upregulated in colon cancer and plays critical roles in its pathogenesis,and could contribute to the effects of dietary LA,as well asω-3 fatty acids,on colon *** this review,we will discuss recent studies about the roles of cytochrome P450 monooxygenases in fatty acid metabolism and its roles in colonic inflammation and colon cancer,and how this information could help us to clarify the health impacts of dietary fatty acids.

关键词： Linoleic acid Polyunsaturated fatty acids ω-3 Fatty acids Colon cancer Colonic inflammation Cytochrome P450 Eicosanoids

Exceptional activity of amino-modified rgO-immobilized PdAu nanoclusters for visible light-promoted dehydrogenation of formic acid

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第7期35卷 428-432页

作者： Yiyue Ding Qiuxiang zhang Lei zhang Qilu Yao gang Feng zhang-Hui Lu Key Laboratory of Energy Catalysis and Conversion of Nanchang College of Chemistry and Chemical EngineeringJiangxi Normal UniversityNanchang 330022China School of Chemistry and Chemical Engineering Nanchang UniversityNanchang 330031China

Formic acid(FA),which is obtainable through CO_(2)hydrogenation with green hydrogen or biomass conversion,has been used as a prospective liquid organic hydrogen carrier(LOHC)because of the abundant advantages of renewability,wide availability,stability,and high volumetric capacity(53 g H_(2)/L).The development of highly efficient catalytic systems to achieve enhanced catalytic activity is attractive but still ***,ultrafine and highly dispersed PdAu nanoclusters(NCs)anchored on amino-modified reduced graphene oxide(ArgO)were successfully synthesized via a facile impregnation-reduction method and applied as a catalyst toward formic acid dehydrogenation(FAD).Benefiting from the promoting effect of amino groups,the strain and ligand effect in the alloy,and the Mott–Schottky effect between PdAu NCs and ArgO,the resultant PdAu/ArgO affords an ultrahigh activity under visible light irradiation with an exceptional turnover frequency value of 10,699.5 h^(-1)at 298 K without any additives,more than 2.6times improvement than that under dark,which is the highest among all reported catalysts under the same *** study provides a green and convenient strategy for developing more efficient and sustainable FAD catalysts and promotes the effective utilization of FA as a prospective renewable LOHC.

关键词： Visible-light-enhanced Hydrogen production Formic acid Pd-Au Heterogeneous catalyst

Implementation of 1.7 kV Silicon Carbide Metal Oxide Semiconductor Field Effect Transistors in Auxiliary Power Supplies for Industrial Applications

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electrical Engineering 2020年第3期6卷 46-55页

作者： Xuning zhang gin Sheh Littelfuse Inc.Round Rock TX 78681USA

An auxiliary power supply(Aux-PS)has become an essential component of electronic equipment for many industrial applications,such as in motor drives,photovoltaic(PV)inverters,uninterruptible power supply(UPS)systems and modular multilevel *** introduction of 1700 V silicon carbide(SiC)metal oxide semiconductor field effect transistors(MOSFETs)is useful for such applications,providing benefits with respect to a low on-state resistance,smaller package,low switching loss and single-switching implementation.A single end flyback Aux-PS is designed for industrial applications with a wide input voltage range using 1.7 kV SiC *** special design tradeoffs involved in the usage of SiC MOSFETs are discussed in detail,such as those with regard to gate driving voltage selection,isolation transformer design considerations,and clamping circuit design details.A 60 W demonstration hardware is developed and tested under different working *** results verify the higher efficiency and better thermal performance of the proposed hardware relative to those of traditional Si solutions.

关键词： Silicon carbide MOSFET wide input range auxiliary power supply

Molecular insights into the transgenerational inheritance of stress memory

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of genetics and genomics 2022年第2期49卷 89-95页

作者： Qian zhang Ye Tian State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100093China Center for Excellence in Animal Evolution and genetics Chinese Academy of SciencesKunming 650223China

There is accumulating evidence to show that environmental stressors can regulate a variety of phenotypes in descendants through germline-mediated epigenetic inheritance. Studies of model organisms exposed to environmental cues(e.g., diet, heat stress, toxins) indicate that altered DNA methylations, histone modifications, or non-coding RNAs in the germ cells are responsible for the transgenerational effects. In addition,it has also become evident that maternal provision could provide a mechanism for the transgenerational inheritance of stress adaptations that result from ancestral environmental cues. However, how the signal of environmentally-induced stress response transmits from the soma to the germline, which may influence offspring fitness, remains largely elusive. Small RNAs could serve as signaling molecules that transmit between tissues and even across generations. Furthermore, a recent study revealed that neuronal mitochondrial perturbations induce a transgenerational induction of the mitochondrial unfolded protein response mediated by a Wnt-dependent increase in mitochondrial DNA levels. Here, we review recent work on the molecular mechanism by which parental experience can affect future generations and the importance of soma-to-germline signaling for transgenerational inheritance.

关键词： Transgenerational inheritance Environmental stress Epigenetic regulation Noncoding RNAs Mitochondrial DNA content Mitochondrial unfolded protein response (UPRmt) Soma-to-germline signaling

The peeling property of Bondi-Sachs metrics for nonzero cosmological constants

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2020年第4期63卷 617-626页

作者： Fangquan Xie Xiao zhang Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

In this paper,we show that the peeling property still holds for Bondi-Sachs metrics with nonzero cosmological constants under the boundary condition given by Sommerfeld's radiation condition together with three nontrivialΛ-independent functions B,a and *** should indicate that the new boundary condition is ***,we construct some nonstationary vacuum Bondi-Sachs metrics without Bondi news,whose Newman-Penrose quantities fall faster than *** provides a new feature of gravitational waves for nonzero cosmological constants.

关键词： Bondi-Sachs metric peeling property cosmological constant

Asymptotics for null-timelike boundary problems for general linear wave equations

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2021年第1期64卷 111-128页

作者： Qing Han Lin zhang Department of Mathematics University of Notre DameNotre DameIN46556USA Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing100190China

We study the linear wave equation□gu=0 in Bondi-Sachs coordinates,for an asymptotically flat Lorentz metric *** consider the null-timelike boundary problem,where an initial value is given on the null surfaceτ=0 and a boundary value on the timelike surface r=*** obtain spacetime Hp-estimates of ru for r>r0 and derive an asymptotic expansion of ru in terms of 1/r as r→∞.

关键词： wave equations radiation field energy estimates asymptotic expansion

Multi-window dilation-and-modulation frames on the half real line

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2020年第12期63卷 2423-2438页

作者： Yunzhang Li Wei zhang College of Applied Sciences Beijing University of TechnologyBeijing 100124China School of Mathematics and Information Sciences Henan University of Economics and LawZhengzhou 450046China

Wavelet and gabor systems are based on translation-and-dilation and translation-and-modulation operators,respectively,and have been studied ***,dilation-and-modulation systems cannot be derived from wavelet or gabor *** study aims to investigate a class of dilation-and-modulation systems in the causal signal space L^2(R+).L^2(R+)can be identified as a subspace of L^2(R),which consists of all L^2(R)-functions supported on R+but not closed under the Fourier ***,the Fourier transform method does not work in L^2(R+).Herein,we introduce the notion ofΘa-transform in L^2(R+)and characterize the dilation-and-modulation frames and dual frames in L^2(R+)using theΘa-transform;and present an explicit expression of all duals with the same structure for a general dilation-and-modulation frame for L^2(R+).Furthermore,it has been proven that an arbitrary frame of this form is always nonredundant whenever the number of the generators is 1 and is always redundant whenever the number is greater than ***,some examples are provided to illustrate the generality of our results.

关键词： frame wavelet frame gabor frame dilation-and-modulation frame multi-window dilation-and-modulation frame

Improvement of Performance of HfS_2 Transistors Using a Self-Assembled Monolayer as gate Dielectric

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2019年第6期36卷 57-60页

作者： Wen-Lun zhang Department of Electrical and Electronic Engineering Tokyo Institute of Technology

This work details a study based on HfS_(2 )transistors utilizing an n-octadecylphosphonic acid-based self-assembled monolayer(SAM)as the gate *** fabrication of the SAM-based two-dimensional(2D)material transistor is simple and can be used to improve the quality of the interface of air-sensitive 2D *** comparison to HfS_(2) transistors utilizing a conventional Al_2O_(3) gate insulator by atomic layer deposition,HfS_(2) transistors utilizing an SAM as the gate dielectric can reduce the operation region from 4 V to 2 V,enhance the field-effect mobility from 0.03 cm^2/Vs to 0.75 cm^2/Vs,improve the sub-threshold swing from 404 m V/dec to 156 m V/dec,and optimize the hysteresis to 0.03 V,thus demonstrating improved quality of the semiconductor/insulator interface.

关键词： Performance HfS2 Self-Assembled Monolayer gate Dielectric