基于基相量循环移位的基波相位和频率高精度快速检测方法

基于基相量循环移位性质,指出采样序列由DFT新算法得到的基波幅角就是信号基波初相角,从而较简捷地获得了所要检测的含谐波电参量的基波分量的初相角,提高了基波相位的跟踪能力。基于等角度间隔采样原理,提出以前述所获得的基波初相角为反馈,构成相位跟踪闭环控制,以自适应调整采样间隔,实现了对被测信号频率的自动跟踪,并达到了减少频谱泄漏,提高基波检测精度的目的。DFT新算法具有递推特性,减少了计算量,实时性较好。上述结果用于有源电力滤波器中,可以精确检测出谐波及无功电流。仿真结果表明,所提出方法的正确性和有效性。

三相电压不对称时广义谐波电流的一种新的检测方法

利用瞬时无功功率理论进行三相电压不对称谐波电流检测时会出现较大的误差,对此将扇合矢量表示法推广应用于三相不对称系统。提出了一种新的扇合变换向量,使三相系统归一化为单相系统,从而简化了三相系统基波有功分量的提取,即使在电网电压不对称时仍能准确有效检测出谐波电流。接着提出并证明了DFT的基相量循环移位性质,根据该性质得到了从三相电流扇合矢量中提取基波有功分量的递推算法,大大减少了计算量,提高了检测实时性。仿真分析对该方法的正确性和可行性进行了证明。

AVO forwarding modeling in two-phase media: multiconstrained matrix mineral modulus inversion

AVO forward modeling is based on two-phase medium theory and is considered an effective method for describing reservoir rocks and fluids. However, the method depends on the input matrix mineral bulk modulus and the rationality of the two-phase medium model. We used the matrix mineral bulk modulus inversion method and multiple constraints to obtain a two-phase medium model with physical meaning. The proposed method guarantees the reliability of the obtained AVO characteristicsin two-phase media. By the comparative analysis of different lithology of the core sample, the advantages and accuracy of the inversion method can be illustrated. Also, the inversion method can be applied in LH area, and the AVO characteristics can be obtained when the porosity, fluid saturation, and other important lithology parameters are changed. In particular, the reflection coefficient amplitude difference between the fast P wave and S wave as a function of porosity at the same incidence angle, and the difference in the incidence angle threshold can be used to decipher porosity.

Material Growth and Device Fabrication of GaN-Based Blue-Violet Laser Diodes

Studies on first GaN-based blue-violet laser diodes(LDs) in China mainland are reported.High quality GaN materials as well as GaN-based quantum wells laser structures are grown by metal-organic chemical vapor deposition method.The X-ray double-crystal diffraction rocking curve measurements show the full-width half maximum of 180″ and 185″ for (0002) symmetric reflection and (10 12) skew reflection,respectively.A room temperature mobility of 850cm2/(V·s) is obtained for a 3μm thick GaN film.Gain guided and ridge geometry waveguide laser diodes are fabricated with cleaved facet mirrors at room temperature under pulse current injection.The lasing wavelength is 405 9nm.A threshold current density of 5kA/cm2 and an output light power over 100mW are obtained for ridge geometry waveguide laser diodes.

Influence of the Interaction Between Phonons and Coulomb Potential on the Properties of a Bound Polaron in a Quantum Dot

The properties of a bound polaron in a parabolic quantum dot with weak electron-LO-phonon coupling under a Coulomb field are studied. The ground state energy of the bound polaron is derived by using a linear combination operator and the perturbation method. The influence of the interaction between phonons with different wave vectors in the recoil process on the ground state energy of the bound polaron is discussed. Numerical calculations are performed,and the results show that the ground state energy increases significantly as the effective confinement length of the quantum dot decreases,considering of the interaction between phonons. When l0〉1.0, the influence of the interaction between phonons on the ground state energy cannot be ignored.

Performances of Five Representative Force Fields on Gaseous Amino Acids with Different Termini

There is a growing interest in the study of structures and properties of biomolecules in gas phase. Applications of force fields are highly desirable for the computational efficiency of the gas phase study. To help the selection of force fields, the performances of five repre- sentative force fields for gaseous neutral, protonated, deprotonated and capped amino acids are systematically examined and compared. The tested properties include relative conforma- tional energies, energy differences between cis and trans structures, the number and strength of predicted hydrogen bonds, and the quality of the optimized structures. The results of BHandHLYP/6-311＋＋G（d,p） are used as the references. GROMOS53A6 and ENCADS are found to perform poorly for gaseous biomoleeules, while the performance of AMBER99SB, CHARMM27 and OPLSAA/L are comparable when applicable. Considering the general availability of the force field parameters, CHARMM27 is the most recommended, followed by OPLSAA/L, for the study of biomolecules in gas phase

Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes

Aluminum (Al) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an Al sensitive lowland indica rice variety IR1552 and an Al tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for Al tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1, 9, 12, respectively, and 1 QTL for root length under Al stress is identical on chromosome 1 after one week and two weeks stress. Comparison of QTLs on chromosome 1 from different studies indicated an identical interval between C86 and RZ801 with gene(s) for Al tolerance. This interval provides an important start point for isolating genes responsible for Al tolerance and understanding the genetic nature of Al tolerance in rice. Four Al induced ESTs located in this interval were screened by reverse Northern analysis and confirmed by Northern analysis. They would be candidate genes for the QTL.

Intrahepatic expression of genes related to metabotropic receptors in chronic hepatitis

AIM： To screen for genes related to metabotropic re- ceptors that might be involved in the development of chronic hepatitis. METHODS： Assessment of 20 genes associated with metabotropic receptors was performed in liver speci- mens obtained by punch biopsy from 12 patients with autoimmune and chronic hepatitis type B and C. For this purpose, a microarray with low integrity grade and with oligonucleotide DNA probes complementary to target transcripts was used. Evaluation of gene expression was performed in relation to transcript level, correlation between samples and grouping of clinical parameters used in chronic hepatitis assessment. Clini- cal markers of chronic hepatitis included alanine and aspartate aminotransferase, ~,-glutamyltranspeptidase, alkaline phosphatase and cholinesterase activity, levels of iron ions, total cholesterol, triglycerides, albumin, glucose, hemoglobin, platelets, histological analysis of inflammatory and necrotic status, fibrosis according to METAVIR score, steatosis, as well as anthropometric body mass index, waist/hip index, percentage of adi- pose tissue and liver size in ultrasound examination. Gender, age, concomitant diseases and drugs were also taken into account. Validation of oligonucleotide microarray gene expression results was done with the use of quantitative real-time polymerase chain reaction （qRT-PCR）. RESULTS： The highest （0.002 〈 P 〈 0.046） expres- sion among genes encoding main components of metabotropic receptor pathways, such as the a subunit of G-coupled protein, phosphoinositol-dependent pro- tein kinase or arrestin was comparable to that of an- giotensinogen synthesized in the liver. Carcinogenesis suppressor genes, such as chemokine ligand 4, tran- scription factor early growth response protein 1 and lysophosphatidic acid receptor, were characterized by the lowest expression （0.002 〈 P 〈 0.046）, while the factor potentially triggering hepatic cancer, transcrip- tion factor JUN-B, had a 20-fold higher expression. The correlation between expression of genes of protein kinases PDPK1, phosphoinositide 3-kinase and protein kinase A （Spearman＇s coefficient range： 0.762-0.769） confirmed a functional link between these enzymes. Gender （P = 0.0046） and inflammation severity, mea- sured by alanine aminotransferase activity （P = 0.035）, were characterized by diverse metabotropic receptor gene expression patterns. The Pearson＇s coefficient ranging from -0.35 to 0.99 from the results of qRT-PCR and microarray indicated that qRT-PCR had certainlimitations as a validation tool for oligonucleotide mi- croarray studies. CONCLUSION： A microarray-based analysis of hepa- tocyte metabotropic G-protein-related gene expression can reveal the molecular basis of chronic hepatitis.

Shape Similarity Measures of Linear Entities

The essential of feature matching technology lies in how to measure the similarity of spatial entities.Among all the possible similarity measures,the shape similarity measure is one of the most important measures because it is easy to collect the necessary parameters and it is also well matched with the human intuition.In this paper a new shape similarity measure of linear entities based on the differences of direction change along each line is presented and its effectiveness is illustrated.

Quantum Phase Transitions in Spin Star Configuration

We consider a generalized spin star configuration that can be solved exactly, with the central spin-1/2 system embedded in an outer ring of N spin-1/2 particles （denoted as spin bath）. In this model, we consider a modified version of the spin star model, by taking into account, besides the interaction of the central spin with the bath, the interactions between the spins of the bath as well. The general expressions of the eigenstates as well as the eigenvalues of the model are derived with the use of the symmetries of system. We then investigate the properties of the ground quantum phase transitions in some limiting cases in the model and show that the occurrence of quantum phase transitions and the desired ground states can be obtained by varying the external control parameters.

Functional Polyethylene Glycol with Carboxyl-supported Platinum as an Efficient Catalysis System for the Hydrosilylation of Alkenes

A series of carboxylated long chain polyethylene glycols(abbreviated as PEGCOOH) has been synthesized and used to support chloroplatinic acid.These supported catalysts were then tested for their efficiency in the hydrosilylation of alkenes.The factors affecting their catalytic properties,e.g.relative molecular mass of polyethylene glycol,reaction temperature,platinum content,and type of alkenes,have been studied.It was found that the activity of the platinum catalyst decreased with increasing length of the polyethylene glycol chain,and increased with reaction temperature.Moreover,these catalysts could be reused several times without a noticeable decrease in activity or selectivity.The reaction pathway leading to excellent selectivity for the β-adduct of hydrosilylation of alkenes with triethoxysilane catalyzed by this catalysis system was discussed.

Exploration of Influential People for Viral Marketing

Exploration of influential people is really a hot issue for effective viral marketing these days. Prior studies overlooked to consider the influence of interaction between users and the authority of users during information dissemination. In this article, we proposed an innovative concept by employing communication strength and authority in order to explore the influential people. First, we calculated communication strength by three kinds of actions including retweets, comments and mentions. Second, we deliberated authority metric by employing total times getting re-tweeted, number of tweets and followers of a user. Then, we propose a novel algorithm called Influential People Label Propagation Algorithm(IPLPA) that considers the proposed metric to explore the influential people in micro-blog networks. We performed extensive experiments to measure the influence and rank of each person within micro-blog network. The comparative study presents that IPLPA depicted effective people while baseline algorithms retrieved low influenced people at top rank. Additionally, influence dissemination also measured for obtained influential people in order to validate proposed concept. The findings of this study would be useful for viral marketing and advertisement campaigns.

EQUIVALENT BASELINE AND INTERFEROMETRIC PHASE OF CLUSTER SATELLITE SAR

The change of the equivalent baseline and interferometric phase of cluster SAR satellites is analyzed when the constellation circles around the Earth and the satellites rotate around the center at the same time. The letter provides assessment of baseline error and phase error which influence the precision of height measurement in the across-track interferometric mode. The mathematical model of cluster satellite movement is built, simulation analyses and the curve of height error are presented. The simulation results show that height measurement error can be compensated by the formulae derived in this letter, therefore, the Digital Elevation Models (DEM’s) are recovered accurately.

Modelling Causes of Temporal Genotype-By-Environment Interaction in Oil Palm Bunch Yield in Nigeria

The objectives of this research were to understand pattern of temporal （year to year） stability in oil palm genotypes and then identify weather variable（s） associated with temporal stability. Stability analysis was performed using the GGE biplot method. The best genotype in one year was not same always in the other year due to changes in the weather conditions over the years. Test environment evaluation revealed that the year 2000 （Y00） was the best representative of the overall environments and most powerful to discriminate genotypes with superior mean yield and temporal stability. The relationship of the climatic factors on the basis of their joint contribution to the development of specific trait varied from the pattern observed when their roles on the same traits were individually assessed. Maximum relative humidity, sunshine and rainfall could help explain the yield fluctuation due to their contribution to the overall yield variation. However, genotypes GI0 and G2 which exhibited high mean performance and stability for BN would be beneficial to the oil palm growers in ensuring steady cash flow from regular bunch yield production.

Recovery of Astaxanthin from Discharged Wastewater During the Production of Chitin

In this paper, studies were carried out to extract astaxanthin from discharged wastewater during the production of chitin and to reveal the scavenging effect of the obtained pigment on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. Different ratios of dichloromethane/methanol (V/V) were used to extract astaxanthin. When the ratio of dichloromethane/methanol was 2:8 and the ratio between the mixed organic solvent (dichloromethane/methanol, 2:8, V/V) and wastewater was 1:1, the highest yield of pigment was obtained (8.4 mg/ 50 mL). The concentration of free astaxanthin in the obtained pigment analyzed by HPLC was 30.02%. The obtained pigment possessed strong scavenging ability on DPPH radical and IC50 was 0.84mg/ml.

Influence of methane on hot filament CVD diamond films deposited on high-speed steel substrates with WC-Co interlayer

Diamond films were deposited on high-speed steel substrates by hot filament chemical vapor deposition （HFCVD） method. To minimize the early formation of graphite and to enhance the diamond film adhesion, a WC-Co coating was used as an interlayer on the steel substrates by high velocity oxy-fuel spraying. The effects of methane content on nucleation, quality, residual stress and adhesion of diamond films were investigated. The results indicate that the increasing methane content leads to the increase in nucleation density, residual stress, the degradation of quality and adhesion of diamond films. Diamond films deposited on high-speed steel （HSS） substrate with a WC-Co interlayer exhibit high nucleation density and good adhesion under the condition of the methane content initially set to be a higher value （4%, volume fraction） for 30 min, and then reduced to 2% for subsequent growth at pressure of 3 kPa and substrate temperature of 800 ℃.

Swelling properties and molecular simulation of PNIPA porous hydrogels

A series of porous intelligent hydrogels, which exhibited appropriate lower critical solution temperature (LCST) and fast response behavior, were synthesized by radiation method. The structure and surface morphology of hydrogels were examined by the infrared radiation and the scanning electron microscopy, respectively. The influences of the content of crosslinking agent and relative molecular mass of polyethylene glycol (PEG) on the swelling properties of hydrogels were discussed. The molecular mechanics simulations were performed to investigate the phase transformation mechanism of poly(N-isopropyl acrylamide) (PNIPA) hydrogel. The results show that macropores are observed in hydrogels, whereas hydrogels prepared without using PEG have a dense surface. LCST of hydrogels increases with the increase of relative molecular mass of PEG. The swelling mechanism of PNIPA porous hydrogels follows non-Fickian diffusion model. The theoretical maximum water absorption S∞ is approximately consistent with experimental value according to the second-order kinetics model established by Schott. The molecule chains of PNIPA hydrogel begin folding and curling, resulting in volume shrinkage at 305 K. There are much intramolecular nonbonding interactions in molecule chains of hydrogels. The porous hydrogels are expected to be applied in the field of artificial intelligence material.

Measurement and correlation of physical properties of aqueous solutions of tetrabutylammonium hydroxide, piperazine and their aqueous blends

The density,viscosity and refractive index of aqueous solutions of tetrabutylammonium hydroxide(TBAOH),piperazine(PZ) and their aqueous blends are determined at several temperatures(303.15 to 333.15 K).All these measured physicochemical properties decreases with an increase in temperature.The density data is used to calculate the coefficient of thermal expansion and excess molar volume of all aqueous binary and ternary solutions.The coefficient of thermal expansion increases with increase in temperatures and concentrations.The negativity of excess molar volume for all the aqueous solution decreased with increase in temperature.Each physical property is correlated with temperature by least square method and the corresponding coefficients for each property are presented.The prediction values from correlations for the physical properties are in good agreement with the experimental values.

Implementation of Controlled Geometric Phase Gate for Two Trapped Neutral Atoms

We propose a scheme for realizing a controlled geometric phase gate for two neutral atoms.We apply thestimulated Raman adiabatic passage to transfer atoms from their ground states into Rydberg excited states, and use theRydberg interaction induced energy shifts to generate geometric phase and construct quantum gates.

Effect of Dietary Nitrogen Corrected-True Metabolism Energy and Digestible Amino Acids on Broiler Breeder Reproductive Performance

A study was conducted to determine the effects of dietary digestible amino acids of feedstuffs and true metabolizable energy corrected for nitrogen on broiler breeder performance in 50 weeks to 64 weeks of age. 140 females and 20 males broiler breeders in 4 treatments with 5 replicates （7 females with a male） were used in the form of a completely randomized trial design 2 ~ 2 factorial. Four experimental diets were formulation based on two factors, first factor was included, two types of Apparent and True Metabolizable Energy corrected for Nitrogen （AMEn and TMEn） and the second factor was included, two types of Total Amino Acids （TAA） and Digestible （DAA） of feedstuffs. The result showed that egg weight, egg production （%） and egg mass （g/hen/day） was significantly different which was affected by diets formulation based on energy and interaction between energy and amino acids （P 〈 0.01）. Treatment 2 （AMEn ＋ DAA） was at the highest level significantly different （P 〈 0.01） in egg weight 68.97 g, egg production 62.45%, and egg mass 43. i g/hen/day. Hatching eggs were significantly different which was affected by diet formulation based on amino acids. Fertility, hatchability and number of chicks per hen were significant different, that were affected by diet formulation based on energy （P 〈 0.05）. Interaction between two factors, were significantly different in two reproductive traits fertility and hatchability （P 〈 0.05）. This experiment showed that diet formulation based on AMEn and DAA for broiler breeder was better and significant on performance.