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A Quadratic Constraint Total Least-squares Algorithm for Hyperbolic Location 被引量:2
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作者 Kai YANG Jianping AN Zhan XU 《International Journal of Communications, Network and System Sciences》 2008年第2期130-135,共6页
A novel algorithm for source location by utilizing the time difference of arrival (TDOA) measurements of a signal received at spatially separated sensors is proposed. The algorithm is based on quadratic constraint tot... A novel algorithm for source location by utilizing the time difference of arrival (TDOA) measurements of a signal received at spatially separated sensors is proposed. The algorithm is based on quadratic constraint total least-squares (QC-TLS) method and gives an explicit solution. The total least-squares method is a generalized data fitting method that is appropriate for cases when the system model contains error or is not known exactly, and quadratic constraint, which could be realized via Lagrange multipliers technique, could constrain the solution to the location equations to improve location accuracy. Comparisons of performance with ordinary least-squares are made, and Monte Carlo simulations are performed. Simulation results indicate that the proposed algorithm has high location accuracy and achieves accuracy close to the Cramer-Rao lower bound (CRLB) near the small TDOA measurement error region. 展开更多
关键词 LOCATION Time DIFFERENCE of ARRIVAL total least-squares
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Nonlinear total least-squares variance component estimation for GM(1,1)model 被引量:2
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作者 Leyang Wang Jianqiang Sun Qiwen Wu 《Geodesy and Geodynamics》 CSCD 2021年第3期211-217,共7页
The solution of the grey model(GM(1,1)model)generally involves equal-precision observations,and the(co)variance matrix is established from the prior information.However,the data are generally available with unequal-pr... The solution of the grey model(GM(1,1)model)generally involves equal-precision observations,and the(co)variance matrix is established from the prior information.However,the data are generally available with unequal-precision measurements in reality.To deal with the errors of all observations for GM(1,1)model with errors-in-variables(EIV)structure,we exploit the total least-squares(TLS)algorithm to estimate the parameters of GM(1,1)model in this paper.Ignoring that the effect of the improper prior stochastic model and the homologous observations may degrade the accuracy of parameter estimation,we further present a nonlinear total least-squares variance component estimation approach for GM(1,1)model,which resorts to the minimum norm quadratic unbiased estimation(MINQUE).The practical and simulative experiments indicate that the presented approach has significant merits in improving the predictive accuracy in comparison with control methods. 展开更多
关键词 GM(1 1)model Minimum norm quadratic unbiased estimation(MINQUE) total least-squares(TLS) Unequal-precision measurement Variance component estimation(VCE)
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Additivity rule for electron-molecule total cross section calculations at 50-5000 eV: a new geometrical approach
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作者 施德恒 孙金锋 +1 位作者 朱遵略 刘玉芳 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第6期2103-2109,共7页
Taking into consideration the changes of the geometric shielding effect in a molecule as the energy of incident electrons varies, this paper presents an empirical fraction, which depends on the energy of incident elec... Taking into consideration the changes of the geometric shielding effect in a molecule as the energy of incident electrons varies, this paper presents an empirical fraction, which depends on the energy of incident electrons, the target's molecular dimension and the atomic and electronic numbers in the molecule. Using this empirical fraction, it proposes a new formulation of the additivity rule. Employing the new additivity rule, it calculates the total cross sections of electron scattering by C2H4, C6H6, C6H14 and C8H18 over the energy range from 50 to 5000eV. In order to exclude the calculation deviations caused by solving the radial Schrodinger equation of electron scattering by atoms, here the atomic cross sections are derived from the experimental total cross section results of simple molecules (H2, O2, CO) via the inversion algorithm. The quantitative total cross sections are compared with those obtained by experiments and other theories, and good agreement is obtained over a wide energy range, even at energy of several tens of eV. 展开更多
关键词 electron scattering total cross section additivity rule geometric shielding effect
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Total cross sections for electron scattering from fluoromethanes:A revised additivity rule method
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作者 谭晓明 赵刚 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第6期167-171,共5页
The additivity rule for electron-molecule scattering is revised by considering the difference between the free atom and the bound atom in the molecule. The total cross sections for electron scattering from fluorometha... The additivity rule for electron-molecule scattering is revised by considering the difference between the free atom and the bound atom in the molecule. The total cross sections for electron scattering from fluoromethanes (CF4, CF3H, CF2H2, and CFH3) are calculated in an energy range from 100 eV to 1500 eV by the revised additivity rule. The present calculations are compared with the original additivity rule results and the available experimental data. Better agreement with each other is obtained. 展开更多
关键词 total cross section electron scattering revised additivity rule
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基于全要素融合的区域自然资源要素配置水平评价——以苏南地区为例
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作者 吴千会 瞿忠琼 《国土与自然资源研究》 2025年第1期66-71,共6页
本文基于苏南地区自然资源特征,以土地资源、水资源、森林资源、湿地资源等自然资源基本要素为切入点,从全要素融合角度建立包括自然资源要素禀赋水平、自然资源要素利用水平和自然资源要素保护水平三个维度的自然资源要素配置水平评价... 本文基于苏南地区自然资源特征,以土地资源、水资源、森林资源、湿地资源等自然资源基本要素为切入点,从全要素融合角度建立包括自然资源要素禀赋水平、自然资源要素利用水平和自然资源要素保护水平三个维度的自然资源要素配置水平评价指标体系,运用综合集成赋权法、“3σ”法则和综合评价等方法,对2012-2021年苏南地区自然资源要素配置水平进行综合分析与评价。结果表明,2012-2021年间苏南地区各市自然资源要素综合配置水平整体上呈波动上升趋势,其中南京市自然资源要素综合配置水平明显优于其他城市,各市自然资源要素禀赋水平呈现先上升后下降趋势,利用水平变化幅度较小,保护水平则呈现大幅度提升。近十年间,仅南京市的自然资源要素综合配置水平达到高效配置和极优配置,苏州市和无锡市维持在一般配置水平,常州市和镇江市由低效配置发展为一般配置,各市无极差配置现象。 展开更多
关键词 自然资源 全要素融合 “3σ”法则 时空动态 苏南地区
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A modification potential method of calculating total cross sections of electrons scattering from complex molecules C2H6, C2F6, C6H6 and C6F6 at 100 eV-5000 eV
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作者 施德恒 孙金锋 +2 位作者 朱遵略 刘玉芳 杨向东 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第6期1278-1283,共6页
A complex optical model potential modified by incorporating the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds between two atoms in a molecule, is first employed to ca... A complex optical model potential modified by incorporating the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds between two atoms in a molecule, is first employed to calculate the total cross sections for electrons scattering from such complex molecules as C2H6, C2F6, C6H6 and C6F6 using the aclditivity rule model at Hartree-Fock level over the energy range from 100 eV to 5000 eV. The total cross sections are quantitatively compared with those obtained by experiments wherever available, and they are in good agreement with each other over a wide energy range. It is shown that the modified potential together with the additivity rule model is completely suitable for the calculation of total cross sections of electrons scattering from such complex molecules as C2H6, C2F6, C6H6 and C6F6 above 200 eV-300 eV. 展开更多
关键词 total cross section electrons scattering additivity rule atomic and molecular collision
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Total cross sections for electrons scattering from simple molecules containing the larger atom sulfur at 30-5000eV
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作者 施德恒 刘玉芳 +2 位作者 孙金锋 杨向东 朱遵略 《Chinese Physics B》 SCIE EI CAS CSCD 2005年第11期2208-2213,共6页
A complex optical model potential modified by the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds, is employed to calculate the total cross sections for electrons scatt... A complex optical model potential modified by the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds, is employed to calculate the total cross sections for electrons scattering from simple molecules (SO2, H2S, OCS, CS2 and SO3) containing the larger atom, sulfur, at 30-5000eV by using the additivity rule model at Hartree-Fock level. The quantitative molecular total cross section results are compared with those obtained in experiments and other calculations wherever available, and good agreement is obtained. It is shown that the additivity rule model together with the complex optical model potential modified by the concept of bonded atom can give the results closer to the experiments than the one unmodified by it. So, the introduction of bonded-atom concept in complex optical model potential betters the accuracy of the total cross section calculations of electrons from the molecules containing the larger atom, sulfur. 展开更多
关键词 atomic and molecular collision additivity rule bonded atom total cross section
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Total cross sections for electron scattering from sulfur compounds
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作者 谭晓明 王艳文 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第2期218-222,共5页
The original additivity rule method cannot give good results for electron scattering from SO,SO2,SO2Cl2,SO2ClF,and SO2F2 molecules at low energy,because the electron-molecule scattering is simply reduced to electron-a... The original additivity rule method cannot give good results for electron scattering from SO,SO2,SO2Cl2,SO2ClF,and SO2F2 molecules at low energy,because the electron-molecule scattering is simply reduced to electron-atom scattering.Considering the difference between the bound atom in a molecule and the corresponding free atom,the original additivity rule is revised.With the revised additivity rule,the total cross sections for electron scattering from these molecules are calculated over a wide energy range below 3000 eV and compared with the available experimental and theoretical data.A better agreement between them is obtained. 展开更多
关键词 the revised additivity rule total cross sections electron scattering
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A Correlation Potential Method for Electron Scattering Total Cross Section Calculations on Several Diatomic and Polyatomic Molecules over Energy Range 10~5000eV
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作者 LIUYu-Fang SHIDe-Heng +2 位作者 SUNJin-Feng ZHUZun-Lue YANGXiang-Dong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期309-314,共6页
A complex optical model potential correlated by the concept of bonded atom, which considers the overlapping effect of electron clouds between two atoms in a molecule, is firstly employed to calculate the total cross s... A complex optical model potential correlated by the concept of bonded atom, which considers the overlapping effect of electron clouds between two atoms in a molecule, is firstly employed to calculate the total cross sections for electron scattering on several molecules (NH3, H2O, CH4, CO, N2, O2, and C2H4) over the energy range 10 ~ 5000 eV using the additivity rule model at Hartree-Fock level. The difference between the bonded atom and the free one in states is that the overlapping effect of electron clouds of bonded atoms in a molecule is considered. The quantitative total cross sections are compared with the experimental data and with the other calculations wherever available and good agreement is obtained over the energy range 10 ~ 5000 eV. It is shown that the correlated calculations are much closer to the available experimental data than the uncorrelated ones at lower energies, especially below 500 eV. Therefore,considering the overlapping effect of electron clouds in the complex optical model potential could be helpful for the better accuracy of the total cross section calculations of electron scattering from molecules. 展开更多
关键词 total cross section additivity rule atomic and molecular collision
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A Modified Potential Method for Electrons Scattering Total Cross Section Calculations on Several Molecules at 30 ~ 5000 eV: CF4, CCl4, CFCl3, CF2Cl2, and CF3Cl
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作者 MA Heng SHI De-Heng +2 位作者 SUN Jin-Feng LIU Yu-Fang ZHU Zun-Lue 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第4期697-701,共5页
A complex optical model potential modified by the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds between two atoms in a molecule, is employed to calculate the total cr... A complex optical model potential modified by the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds between two atoms in a molecule, is employed to calculate the total cross sections (TCS5) for electrons scattering from several molecules (CF4, CCl4, CFCl3, CF2 Cl2, and CF3 Cl) over an incident energy range 30 - 5000 eV using the additivity rule model at Hartre-Fock level. The quantitative TCS5 are compared with those obtained by experiments and other theories wherever available, and good agreement is obtained above 100 eV. It is shown that the modified potential can successfully calculate the TCS5 of electron-molecule scattering over a wide energy range, especially at lower energies. 展开更多
关键词 total cross section additivity rule atomic and molecular collision
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Total Cross Sections for Electron Scattering on Polyatomic Molecules (CH4, CO2,NO2, and N2O) at 10~3000 eV
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作者 SUNJin-Feng XUBin +1 位作者 LIUYu-Fang SHIDe-Heng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第5期895-899,共5页
A new modified formulation of the Additivity Rule (AR) was proposed to calculate the total electron scattering cross sections for CH4, CO2, NO2, and N2O, considering the overlapping between atoms in molecules and the ... A new modified formulation of the Additivity Rule (AR) was proposed to calculate the total electron scattering cross sections for CH4, CO2, NO2, and N2O, considering the overlapping between atoms in molecules and the not fully transparency of the molecules. The present calculation covers the range of impact energy from 10 to 3000 eV. The results are compared with experimental data and other theories where available. The atoms are presented by spherical complex optical potential, which is composed of static, exchange, polarization, and absorption terms. 展开更多
关键词 total cross section additivity rule optical potential model
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Study on medication rules of Chinese herbs in the regulation of necroptosis based on network pharmacology and data mining
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作者 GUO Jia‑min GUO Xiao‑fei +3 位作者 SUN Shi‑yi LI Jing‑jing DENG Xiao‑xi ZHANG Ping 《Journal of Hainan Medical University》 CAS 2023年第8期32-39,共8页
Objective:To analyze the basis and medication rules of Chinese herbs in the regulation of necroptosis.Methods:With the help of GeneCards,DrugBank,TTD,DisGeNET,OMIM database to collect the action targets of necroptosis... Objective:To analyze the basis and medication rules of Chinese herbs in the regulation of necroptosis.Methods:With the help of GeneCards,DrugBank,TTD,DisGeNET,OMIM database to collect the action targets of necroptosis,the TCMSP database to obtain the target‑related compounds and Chinese herbs,and the ADME criteria and Lipinski rule as the conditions for screening,to build the target‑compound,target‑compound‑Chinese herbs network.The information of Chinese herbal medicine's sexual taste and meridian was collected,and the drug use pattern was analyzed.The information on the property,flavor and channel tropism of Chinese herbs was collected to analyze the medication laws.Molecular docking of core targets and compounds in the network with AutoDockTools software,and PyMOL software was used to display the combinations with good docking results.Results:A total of 12 potential targets acting on necroptosis were obtained,matching to 191 candidate compounds and 366 herbal medicines.Quercetin,wogonin,triptolide,licochalcone a,ellipticine are more important and may be the main small molecule substances underlying the regulation of necroptosis.The more important Chinese herbs are Licorice,Forsythia,Salivae Miltiorrhizae,Ginkgo Leaf,Eucommia ulmoides Oliv,etc.The herbal medicines are mainly bitter and pungent,with cold and warm taste,which were attributed to the liver and lung meridians.BCL2‑beta‑sitosterol、MAPK14‑luteolin、MAPK14‑formononetin、TP53‑formononetin are better molecular docking results,which have strong docking activity.Conclusion:The study systematically analyzes the material basis of regulating necroptosis and summarizes the general rule of regulating necroptosis in Chinese medicine,which provides ideas for clinical development of agents to interfere with necroptosis. 展开更多
关键词 NECROPTOSIS Network pharmacology Medication rules New drug development total laparoscopic total gastrectomy
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Are the Rules of Classical Epidemiology Valid Today?
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作者 Béla Ralovich 《Open Journal of Applied Sciences》 2022年第2期216-223,共8页
Both HIV and COVID-19 infections show that the centuries-old scientifically established epidemiological rules are still valid today, but they have to be applied in time and in a correct manner. Furthermore, when incom... Both HIV and COVID-19 infections show that the centuries-old scientifically established epidemiological rules are still valid today, but they have to be applied in time and in a correct manner. Furthermore, when incompetent funded “rights defenders” or political organizations referring to human rights have spread lies and have spoken against the experts-created epidemiological rules as well as the acceptance of vaccination, they have not only cheated everybody but they could also be accused by the crime of endangering of great mass of people which action can cause occasionally death also! It has to be also stated that the interests and rights of the total population are always over that of a single person and also realized that all pathogens live their own life among us according to their determinacy independently from our rights and interests! 展开更多
关键词 Infectious Diseases EPIDEMIOLOGY Epidemiological Experts rules and Restrictions Incompetent Persons Vaccination Human Rights Interests of the total Population
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高效液相色谱-质谱联用鉴定黄芩总苷元提取物中黄酮类成分 被引量:1
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作者 陈宁 郝俊菊 +3 位作者 殷康明 陆宇婷 宋敏 杭太俊 《药学与临床研究》 2024年第3期209-217,共9页
目的:使用高效液相色谱-四极杆-飞行时间串联质谱(HPLC-Q-TOF/MS)技术,分离鉴定黄芩总苷元提取物中的黄酮类成分,并总结其裂解规律。方法:采用岛津LX-20210330-01 C_(18)(250 mm×4.6 mm,5μm)色谱柱,以0.1%甲酸为流动相A,甲醇-乙腈... 目的:使用高效液相色谱-四极杆-飞行时间串联质谱(HPLC-Q-TOF/MS)技术,分离鉴定黄芩总苷元提取物中的黄酮类成分,并总结其裂解规律。方法:采用岛津LX-20210330-01 C_(18)(250 mm×4.6 mm,5μm)色谱柱,以0.1%甲酸为流动相A,甲醇-乙腈(50∶50)为流动相B进行梯度洗脱,对黄芩总苷元提取物中的黄酮类成分进行分离,利用电喷雾离子化-四极杆-飞行时间串联质谱高分辨测定各成分母离子及其子离子的准确质量,结合电喷雾离子源正、负离子模式下的质谱信息和色谱保留时间进行结构鉴定。结果及结论:除了黄芩素和汉黄芩素两个已知成分外,从黄芩总苷元提取物中共鉴定出31种黄酮类成分,包括12种苷类与19种苷元,其中有3个化合物为本研究首次鉴定,并分析归纳了黄酮类成分在电喷雾离子源正、负离子模式下的质谱碎片裂解规律。 展开更多
关键词 黄芩总苷元提取物 黄酮 高效液相色谱-四极杆-飞行时间串联质谱 裂解规律
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全营养乳液贮藏期品质变化及动力学研究
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作者 武婳 范柳萍 +1 位作者 于群 张涛 《食品与发酵工业》 CAS CSCD 北大核心 2024年第11期151-160,共10页
为探究全营养乳液在贮藏过程中的品质变化规律,将其置于不同温度(20、30、40℃)下贮藏,对粒径、电位、离心沉淀率、色差、p H、维生素C、维生素E和感官评分变化情况进行回归性分析并研究了稳定动力学。结果表明,贮藏温度是影响全营养乳... 为探究全营养乳液在贮藏过程中的品质变化规律,将其置于不同温度(20、30、40℃)下贮藏,对粒径、电位、离心沉淀率、色差、p H、维生素C、维生素E和感官评分变化情况进行回归性分析并研究了稳定动力学。结果表明,贮藏温度是影响全营养乳液品质变化的重要指标。随着贮藏时间的延长,平均粒径增加了77.19%~156.74%,电位绝对值减小了27.36%~48.31%。a^(*)、b^(*)值增加,亮度减弱。维生素C对温度的敏感性高且降解符合一级反应,半衰期从144 d降低至81 d,反应活化能E_(a)为21.75 k J/mol。p H、粒径和离心沉淀率遵循零级反应动力学,色差、电位、维生素C含量的变化遵循一级反应动力学。热力学参数ΔH>0,ΔS<0,属于非自发进行的吸热反应。ΔG依赖于温度变化,随温度的增加呈上升趋势。该研究为全营养乳液的贮藏保质提供了理论参考依据。 展开更多
关键词 全营养乳液 贮藏温度 降解规律 品质变化 动力学
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ATR全站仪的棱镜光斑重心识别与照准纠偏研究
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作者 鄢士程 解广成 +2 位作者 崔洋 辛全明 生晨 《长春理工大学学报(自然科学版)》 2024年第2期16-22,共7页
智能化全站仪内置的CCD相机是测量活动中识别目标棱镜的载体,其接收反射红外线形成的光斑图像是目标识别及照准度判定的重要依据。实验以目标区域棱镜的RGB、灰度图像、光斑图像(点云化)作为研究依据,基于提出的圆形度、光斑映射系数、... 智能化全站仪内置的CCD相机是测量活动中识别目标棱镜的载体,其接收反射红外线形成的光斑图像是目标识别及照准度判定的重要依据。实验以目标区域棱镜的RGB、灰度图像、光斑图像(点云化)作为研究依据,基于提出的圆形度、光斑映射系数、散射性三个特征条件使用随机森林算法建立光斑精识别模型,再利用光斑离散度质心算法找寻光斑重心。最后以四象限法则分割光斑重心落点进而形成实验场误差线,分象限进行照准误差纠偏。实验表明此方法可以很好地识别棱镜光斑重心和进行精确照准,具有一定的可行性。 展开更多
关键词 智能化全站仪 特征条件 随机森林算法 四象限法则
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Unified Control Theory from PID to ACPID
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作者 Zhezhao Zeng Yuqi Tang 《Advances in Pure Mathematics》 2024年第7期523-545,共23页
To address the challenge of achieving unified control across diverse nonlinear systems, a comprehensive control theory spanning from PID (Proportional-Integral-Derivative) to ACPID (Auto-Coupling PID) has been propose... To address the challenge of achieving unified control across diverse nonlinear systems, a comprehensive control theory spanning from PID (Proportional-Integral-Derivative) to ACPID (Auto-Coupling PID) has been proposed. The primary concept is to unify all intricate factors, including internal dynamics and external bounded disturbance, into a single total disturbance. This enables the mapping of various nonlinear systems onto a linear disturbance system. Based on the theory of PID control and the characteristic equation of a critically damping system, Zeng’s stabilization rules (ZSR) and an ACPID control force based on a single speed factor have been designed. ACPID control theory is both simple and practical, with significant scientific significance and application value in the field of control engineering. 展开更多
关键词 Insert Nonlinear Systems PID Control ACPID Control total Disturbance Unified Control Theory Zeng’s Stabilization rules (ZSR)
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电力系统精细规则的研究 被引量:35
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作者 蒋维勇 孙宏斌 +2 位作者 张伯明 吴文传 王康 《中国电机工程学报》 EI CSCD 北大核心 2009年第4期1-7,共7页
在分析传统运行规则的基本形式和弊端的基础上,进一步阐述精细规则的概念。针对系统输电断面,提出建立精细规则的方法:针对静态安全,精细规则的建立基于灵敏度技术;针对暂态安全,精细规则的建立采用数据挖掘技术,由建立训练集、特征选... 在分析传统运行规则的基本形式和弊端的基础上,进一步阐述精细规则的概念。针对系统输电断面,提出建立精细规则的方法:针对静态安全,精细规则的建立基于灵敏度技术;针对暂态安全,精细规则的建立采用数据挖掘技术,由建立训练集、特征选择、知识表示等步骤组成,其中训练集采用基于连续潮流的极限传输容量计算方法,特征选择采用一种新的基于信息理论的方法,知识表示采用最小二乘拟合。对四机双区域测试系统和某省级电网分别进行精细规则的算例研究,结果表明,精细规则考虑了更精细的电网特征状态,对在线运行方式的适应能力更强,可在保证系统安全的前提下有效挖掘输电走廊的输电潜力,提供的灵敏度还有助于控制决策。 展开更多
关键词 精细规则 极限传输容量 数据挖掘 信息理论 特征选择
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白酒贮存中酸酯变化规律及酒龄预测方法研究 被引量:18
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作者 王伟 张生万 +3 位作者 杜小威 史静霞 杨李 李美萍 《酿酒科技》 北大核心 2007年第10期17-19,共3页
揭示了65%vol、53%vol、45%vol、38%vol白酒中的总酸总酯随贮存时间的变化规律,总酸含量随贮存时间的延长而增加,酒度越低,总酸增加越快;总酯随贮存时间的延长而减少,酒度越低,总酯减少越大。在一定时间内,总酸增加量和总酯减少量均随... 揭示了65%vol、53%vol、45%vol、38%vol白酒中的总酸总酯随贮存时间的变化规律,总酸含量随贮存时间的延长而增加,酒度越低,总酸增加越快;总酯随贮存时间的延长而减少,酒度越低,总酯减少越大。在一定时间内,总酸增加量和总酯减少量均随酒度降低而增大。说明贮存白酒应以高度酒贮存为好。并利用总酸总酯含量对贮存时间进行建模,对白酒的酒龄进行预测。建模的相关系数(R)与交互检验相关系数(Q)分别为0.9314和0.9145;建模的标准偏差(SD)为1.4176,交互检验的标准偏差(SDcv)为1.5757。结果表明,所建模型具有良好的稳定性和预测能力,较好地揭示了白酒的贮存时间与总酸、总酯变化规律,是一种预测酒龄的有效手段。 展开更多
关键词 白酒 总酸总酯 酒度 变化规律 酒龄
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不同土地利用方式下三江平原东北部土壤有机碳和全氮分布规律 被引量:19
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作者 王书伟 颜晓元 +4 位作者 林静慧 夏永秋 孙磊 胡玉婷 廖千家骅 《土壤》 CAS CSCD 北大核心 2010年第2期190-199,共10页
利用在全国采集的1400个典型农田剖面数据(其中在此研究区域有53个剖面),系统分析了不同土地利用方式下三江平原东北部土壤有机C和全N的分布规律。三江平原东北部典型农田0~20cm土壤有机C和全N的平均含量是22.7g/kg和1.84g/kg,20~100c... 利用在全国采集的1400个典型农田剖面数据(其中在此研究区域有53个剖面),系统分析了不同土地利用方式下三江平原东北部土壤有机C和全N的分布规律。三江平原东北部典型农田0~20cm土壤有机C和全N的平均含量是22.7g/kg和1.84g/kg,20~100cm平均含量为13.0g/kg和1.08g/kg,不同土壤类型和种植作物下土壤有机C和全N分布没有显著性差异(p>0.05)。与第二次土壤普查时三江平原东北部典型剖面土壤有机C和全N数据进行比较发现,0~20cm有机C和全N含量呈现下降趋势,而20~100cm呈现增加趋势。 展开更多
关键词 三江平原 碳氮 分布规律
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