检索结果-南通市图书馆

Journal of Environmental Sciences 2006年第5期18卷 1020-1023页

作者： ZOU zhi-hong YUN Yi SUN Jing-nan School of Economics and Management Beihang University Beijing 100083 China

Considering the difficulty of fuzzy synthetic evaluation method in calculation of the multiple factors and ignorance of the relationship among evaluating objects, a new weight evaluation process using entropy method was introduced. This improved method for determination of weight of the evaluating indicators was applied in water quality assessment of the Three Gorges reservoir area. The results showed that this method was favorable for fuzzy synthetic evaluation when there were more than one evaluating objects. One calculation was enough for calculating every monitoring point. Compared with the original evaluation method, the method predigested the fuzzy synthetic evaluation process greatly and the evaluation results are more reasonable.

关键词： water quality evaluation fuzzy weight of evaluating indicator entropy method

Lovastatin production by Aspergillus terreus in solid-state fermentation

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第9期8卷 1521-1526页

作者： WEI Pei-lian XU zhi-nan CEN Pei-lin Institute of Biochemical Engineering Department of Chemical Engineering ＆ Bioengineering Zhejiang University Hangzhou 310027 China Department of Biochemical Engineering Zhejiang University of Science and Technology Hangzhou 310023 China

Lovastatin production by Aspergillus terreus ATCC 20542 in solid-state fermentation （SSF） was studied. Various substrates were used to evaluate the ability ofA. terreus to produce lovastatin. The results showed that either rice or wheat bran was suitable substrate for lovastatin production in SSF. The maximum yield of lovastatin （2.9 mg/g dry substrate） using rice as substrate was achieved after incubating for 11 d at the following optimized process parameters： 50%-60% initial moisture content, pH 5.5, incubation temperature 28 ℃.

关键词： Solid-state fermentation (SSF) Rice Lovastatin Aspergillus terreus

Canonical correlation analysis of hydrological response and soil erosion under moving rainfall

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第5期14卷 353-361页

作者： Qi-hua RAN zhi-nan SHI Yue-ping XU Institute of Hydrology and Water Resources Zhejiang University

The impacts of rainfall direction on the degree of hydrological response to rainfall properties were investigated using comparative rainfall-runoff experiments on a small-scale slope(4 m×1 m),as well as canonical correlation analysis(CCA).The results of the CCA,based on the observed data showed that,under conditions of both upstream and downstream rainfall movements,the hydrological process can be divided into instantaneous and cumulative responses,for which the driving forces are rainfall intensity and total rainfall,and coupling with splash erosion and wash erosion,*** response of peak runoff(Pr)to intensity-dominated rainfall action appeared to be the most significant,and also runoff(R)to rainfall-dominated action,both for upstream-and downstream-moving ***,the responses of sediment erosion in downstream-moving condition were more significant than those in upstream-moving *** study indicated that a CCA between rainfall and hydrological characteristics is effective for further exploring the rainfall-runoff-erosion mechanism under conditions of moving rainfall,especially for the downstream movement condition.

关键词： Moving rainfall Runoff Sediment erosion Canonical correlation analysis(CCA)

Belief propagation list bit-flip decoder for polar codes

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2021年第9期64卷 224-231页

作者： Yuyu YANG Yaoyue HU zhiwen PAN nan LIU Shenjie xia National Mobile Communications Research Laboratory Southeast University Huawei Technologies Co.Ltd.

Belief propagation(BP) decoder is a low decoding latency algorithm for polar codes. However,the block error rate(BLER) performance of the BP decoder is inferior to the cyclic redundancy check(CRC)aided successive cancellation list(CA-SCL) decoder with medium list size for polar codes. Thus, in this paper, we introduce a bit-flip method into the belief propagation list(BPL) decoder and propose a BPL bitflip(BPLF) decoder to improve the BLER performance of BP-based decoder for polar codes. The proposed decoder is based on a CRC-aided belief propagation list(CA-BPL) decoder, and the error-prone bits are obtained from the decoded result to construct flip bits set(FBS). The bits in FBS are flipped to obtain the correct decoding result. Moreover, the simulation results show that the BLER of the proposed BPLF decoder is significantly superior to that of the CA-BPL despite having the same list size, e.g., there is 0.75 dB gain at BLER = 10.4 with list size 64. Furthermore, the decoding complexity and latency of the proposed BPLF decoder are only slightly higher than those of CA-BPL decoder with the same list size in medium to high signal-to-noise ratio(SNR) region.

关键词： polar codes belief propagation bit-flip list decoder

BODIPY@Ir(Ⅲ)Complexes Assembling Organic nanoparticles for Enhanced Photodynamic Therapy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2018年第3期36卷 417-424页

作者： Yang Liu nan Song Li Chen zhi-Gang Xie Department of Chemistry Northeast Normal UniversityChangchun 130024China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China

We present a new cyclometalated Ir(III)complexes IrBDP,which could self-assemble into organic nanoparticles(IrBDP NPs).IrBDP NPs show enhanced photodynamic effect and can be engulfed by HeLa cells for cell imaging as ... 详细信息

关键词： BODIPY Photodynamic therapy Iridium complex

The Extension of a Quantized Borcherds Superalgebra by a Hopf Algebra

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2016年第3期32卷 363-372页

作者： Li xia YE zhi xiang WU Department of Mathematics Zhejiang International Studies University School of Mathematical Sciences Zhejiang University

A two-parameter quantum group is obtained from the usual enveloping algebra by adding two commutative grouplike elements. In this paper, we generalize this procession further by adding commutative grouplike elements b（ik）, c（ik）, g（ik）, h（ik）（i ∈I, k = 1,..., mi） of a Hopf algebra H to the quantized enveloping algebra Uq（G） of a Borcherds superalgebra G defined by a symmetrizable integral Borcherds–Cartan matrix A =（aij）i,j∈I. Therefore, we define an extended Hopf superalgebra HUq（G）. We also discuss the basis and the grouplike elements of HUqG.

关键词： Borcherds superalgebra Hopf algebra quantized enveloping algebra

Quick estimation of the D_(pb) for predicting the strength of chemical bond in situ

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2013年第10期24卷 912-916页

作者： xia Du Dong-xia Zhao Zhong-zhi Yang Chemistry and Chemical Engineering Faculty Liaoning Normal University

An approximate method has been established to calculate the depth of the potential acting on an electron in a molecule at the saddle point along a chemical bond, denoted by Dpb. It is a new indicator which can be used for predicting the strength of a chemical bond. In this work, as a practical application for demonstrating this method, we calculated the Dpb of deoxyribonucleosides and ribonucleosides along all C-H and N-H chemical bonds using the method. The results are in fair agreement with those results of previously reported experimental and theoretical observations,

关键词： Bond strength Dpb Deoxyribouncleosides Ribonucleosides

An SIS epidemic model with diffusion

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2017年第2期32卷 127-146页

作者： XU zhi-ting CHEN Dan-xia School of Mathematical Sciences South China Normal UniversityGuangzhou 510631China.

The aim of this paper is to study the diffusion. We first study the well-posedness of the dynamics of an SIS epidemic model with model. And then, by using linearization method and constructing suitable Lyapunov function, we establish the local and global stability of the disease-free equilibrium and the endemic equilibrium, respectively. Furthermore, in view of Schauder fixed point theorem, we show that the model admits traveling wave solutions con- necting the disease-free equilibrium and the endemic equilibrium when R0 〉 1 and c 〉 c^＊. And also, by virtue of the two-sided Laplace transform, we prove that the model has no traveling wave solution connecting the two equilibria when R0 〉 1 and c ∈（0, c^＊）.

关键词： SIS epidemic model traveling wave solution local stability global stability diffusive.

A modified predictive control strategy of three-phase grid-connected converters with optimized action time sequence

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2013年第4期56卷 1017-1028页

作者： SONG ZhanFeng xia ChangLiang LIU Tao DONG nan School of Electrical Engineering and Automation Tianjin University Tianjin Key Laboratory of Advanced Technology of Electrical Engineering and Energy Tianjin Polytechnic University Beijing Electric Power Company

Due to the excellent dynamic performance,the Finite Control Set Model Predictive Control has been widely used in various types of ***,when Finite Control Set Model Predictive Control is adopted,the switching frequency of converters varies significantly with system operating ***,constant-frequency predictive control strategy has been *** active voltage vectors and a zero voltage vector are selected within each sampling *** action time sequence is then *** to the unsymmetrical distribution of current variation rates around zero,the calculated value of the voltage-vector action time will turn up *** to common sense,the voltage-vector action time is greater than or equal to *** action time is normally forced to zero whenever a negative value is predicted,resulting in the control failure and performance *** solve this problem,this paper proposes modified *** modified strategy examines the action time calculated *** negative action time comes out,the modified strategy reselects the active voltage vector accordingly,instead of forcing the action time to be *** action time sequence is further determined by minimizing the cost *** effectiveness of the modified strategy is clearly verified by experimental tests,and analytical remarks are all founded in practical results.

关键词： converter cost function optimized action time sequence negative action time

Experimental study on the local similarity scaling of the turbulence spectrum in the turbulent boundary layer

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2009年第6期52卷 900-908页

作者： xia ZhenYan JIANG nan TIAN Yan WANG YuChun Department of Mechanics Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Modern Engineering Mechanics Tianjin 300072China

The streamwise fluctuating velocity in the turbulent boundary layer is measured under approximately medium Reynolds Number by hot wire in order to investigate the scaling properties of the overlapped turbulent spectrum among energy-containing area, inertial subrange and dissipation range based on FFT analysis. The experiment indicates that the high Reynolds flow reported before is not indispensable to produce -1 scaling. So far as the measured position is provided with much higher spatial resolution and enough closing to the wall, -1 scaling is determinate to exist when approaching medium Reynolds. The scaling ranges are supposed to begin at inner scale and end in outer scale, which reveals the local similarity of the energy spectrum over the energy-containing eddies near the wall. In the logarithmic area (y+ > 130), -5/3 scaling occurs in the energy spectrum, while moving away from the wall with Reynolds numbers increasing, the inertial subrange extends to the lower wavenumbers. On the condition k1η 0.1, the curves of the turbulence spectrum in the logarithmic layer are superposed, which expresses the similarity of turbulence energy distributed in Komogorov scaling area and exhibits local isotropy characteristics by virtue of the viscous dissipation.

关键词： turbulent boundary layer -1 spectrum -5/3 spectrum energy-containing eddy inertial subrange local isotropy