期刊文献+
共找到45篇文章
< 1 2 3 >
每页显示 20 50 100
P系数法在确定煤矿采空区地表移动参数中的应用 被引量:2
1
作者 杨梅忠 席国强 孟东芳 《煤炭工程》 北大核心 2012年第1期99-101,共3页
通过对榆林市典型矿井地层、采空区地表沉陷变形监测数据分析,利用P系数法确定下沉系数q、主要影响角正切tanβ、拐点移动距s、水平移动系数b和开采影响传播角θ这五个重要参数,结果显示下沉系数采用上覆松散层和上覆基岩进行计算,结果... 通过对榆林市典型矿井地层、采空区地表沉陷变形监测数据分析,利用P系数法确定下沉系数q、主要影响角正切tanβ、拐点移动距s、水平移动系数b和开采影响传播角θ这五个重要参数,结果显示下沉系数采用上覆松散层和上覆基岩进行计算,结果与实际比较相差较大,而只采用上覆基岩计算,所得结果与实际接近。文章并根据所得参数利用概率积分法对该矿井306工作面地表变形进行预测,预测结果显示,与邻矿井201工作面实际监测数据相吻合,因此采用P系数法确定地表移动参数是可行的。 展开更多
关键词 地表移动参数 p系数 上覆基岩 变形预测
下载PDF
对吴震东公式中引入截面形状修正系数P的分析和讨论(下) 被引量:2
2
作者 邓寿昌 李克俭 《低温建筑技术》 北大核心 2000年第4期6-8,共3页
针对国内若干文献[2 ,3] 对吴震东公式引入“断面形状系数P”发表了不同看法和意见 ,认真研究并分析了湖南大学及新疆建筑科学研究所分别为验证吴震东公式与Ъ г Скрамтаева公式计算精度所做的试验 ,从理论上严格论述了“断... 针对国内若干文献[2 ,3] 对吴震东公式引入“断面形状系数P”发表了不同看法和意见 ,认真研究并分析了湖南大学及新疆建筑科学研究所分别为验证吴震东公式与Ъ г Скрамтаева公式计算精度所做的试验 ,从理论上严格论述了“断面形状系数P”是人为虚构的 ,用来对吴震东公式进行修正是错误的。同时指出 :“吴震东公式来源于广义蓄热微分方程严格完整的数学与析解 。 展开更多
关键词 吴震东公式 混凝土 截面形状系数p
下载PDF
福建省地表径流N、P流失系数的测算 被引量:1
3
作者 李斌 《武夷科学》 2009年第1期58-63,共6页
通过对福建省12个地表径流监测点径流水中氮磷含量的分析,得出了福建省地表径流的N、P流失系数。结果表明:我省总氮流失系数为0.414%-7.862%,总磷流失系数为0.032%-1.314%。
关键词 福建省 地表径流N p流失系数
下载PDF
P-Ⅲ型频率曲线离均系数φ_P的一种简易求解方法 被引量:2
4
作者 张杨波 《甘肃水利水电技术》 2002年第4期267-268,共2页
介绍了一种计算P -Ⅲ型频率曲线离均系数p 的简易方法。
关键词 p-Ⅲ型频率曲线 离均系数Φp 水文频率 计算
下载PDF
具有垂直和水平对称轴的横向各向同性模型的P波反射系数
5
作者 AndreasRüger 金抒辛 《石油物探译丛》 1997年第6期65-75,共11页
对振幅随偏移距变化的分析来说,研究各向异性介质中的P波反射系数是重要的。直接对反射系数做数值估计时,数值解不能从解析角度反映各向异性对AVO特征的影响。 为解决这个问题,本文为计算具有垂直对称轴的横向各向同性介质中水平边界的... 对振幅随偏移距变化的分析来说,研究各向异性介质中的P波反射系数是重要的。直接对反射系数做数值估计时,数值解不能从解析角度反映各向异性对AVO特征的影响。 为解决这个问题,本文为计算具有垂直对称轴的横向各向同性介质中水平边界的P波反射系数提供一种改进了的近似方法,其解中有一个与以前文献中方程相同的描述反射系数低次项角度变化的AVO梯度项,但对大入射角来说,这个解更为确切。这样,精细的近似可以扩展到具有水平对称轴的横向各向同性(HTI)介质。这种情况通常是由一组垂直裂缝所引起的。对比HTI介质的两个垂直对称平面中入射P波的近似反射系数可以看出:AVO梯度的方位变化是横波分裂参数γ和各向异性参数的函数。其中,各向异性参数描述在具有对称轴的垂直平面中近似垂直传播的P波各向异性。 展开更多
关键词 AVO 各向异性 p波反射系数 波传播 表面波
下载PDF
Reflection coefficients of P-SV waves in weak anisotropic media 被引量:4
6
作者 刘前坤 韩立国 +1 位作者 王恩利 单刚义 《Applied Geophysics》 SCIE CSCD 2008年第1期18-23,共6页
We introduce the Thomsen anisotropic parameters into the approximate linear reflection coefficient equation for P-SV wave in weakly anisotropic HTI media. From this we get a new, more effective, and practical reflecti... We introduce the Thomsen anisotropic parameters into the approximate linear reflection coefficient equation for P-SV wave in weakly anisotropic HTI media. From this we get a new, more effective, and practical reflection coefficient equation. We performed forward modeling to AVO attributes, obtaining excellent results. The combined AVO attribute analysis of PP and PS reflection data can greatly reduce ambiguity, obtain better petrophysical parameters, and improve parameter accuracy. 展开更多
关键词 Weak anisotropy p-SV wave reflection coefficient.
下载PDF
利用Rüschendorf方法构造新的Copula 被引量:1
7
作者 彭定忠 何帆 刘朝才 《湖南理工学院学报(自然科学版)》 CAS 2020年第1期6-9,共4页
Copula建模被广泛应用于金融保险、地质统计学和水文学等领域.本文利用Rüschendorf方法构造了新的Copula,并研究其相关性测度.
关键词 COpULA Rüschendorf方法 Kendall’s相关系数 Spearman’s p相关系数
下载PDF
Forward Modeling of the Relationship Between Reflection Coefficient and Incident Angle of the P Wave in a Coal Seam 被引量:12
8
作者 DONG Shou-Hua YUE Jian-hua 《Journal of China University of Mining and Technology》 EI 2006年第1期5-7,12,共4页
Although the Zoeppritz equation is suitable for a single interface in a thick deposit, it has some limitations for composite reflection waves from both the floor and the roof of coal seams. Based on the ray model, the... Although the Zoeppritz equation is suitable for a single interface in a thick deposit, it has some limitations for composite reflection waves from both the floor and the roof of coal seams. Based on the ray model, the relationship of the overall reflection coefficient of composite reflection P waves, from coal seam versus incidence angle (AVO), is dis- cussed. The result shows that: 1) the overall reflection coefficient of composite reflection waves from coal seams is a negative value and is determined mainly by the lithology of roof and floor, which is different from the reflection coeffi- cient of a single interface; 2) if the incidence angle ranges from 0° to 6°, the reflection coefficient of composite waves of a coal seam does not change with the incidence angle and 3) if the incidence angle ranges from 6–60° , the reflection coefficient increases monotonically. 展开更多
关键词 coal seam composite wave reflection coefficient p wave
下载PDF
Tunneling Conductance in Normal Metal/Insulator/Triplet Superconductor Junction 被引量:3
9
作者 LI Xiao-Wei 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2X期381-384,共4页
Tunneling conductance in normal metal/insulator/triplet superconductor junctions is studied theoretically as a function of the bias voltage at zero temperature and finite temperature. The results show there are zero-b... Tunneling conductance in normal metal/insulator/triplet superconductor junctions is studied theoretically as a function of the bias voltage at zero temperature and finite temperature. The results show there are zero-bias conductance peak, zero-bias conductance dip and double-minimum structures in the spectra for p-wave superconductor junctions. The existence of such structures in the conductance spectrum can be taken as evidence that the pairing symmetry of Sr2RuO4 is p-wave symmetry. 展开更多
关键词 triplet superconductor p-WAVE tunneling conductance
下载PDF
New Explicit Solutions of (1+1)-Dimensional Variable-Coefficient Broer-Kaup System 被引量:1
10
作者 闫志莲 周建平 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第12期965-970,共6页
By using the compatibility method, many explicit solutions of the (1+1)-dimensional variable-coefficientBroer-Kaup system are constructed, which include new solutions expressed by error function, Bessel function, expo... By using the compatibility method, many explicit solutions of the (1+1)-dimensional variable-coefficientBroer-Kaup system are constructed, which include new solutions expressed by error function, Bessel function, exponentialfunction, and Airy function.Some figures of the solutions are given by the symbolic computation system Maple. 展开更多
关键词 variable coefficient Broer-Kaup system explicit solution SYMMETRY
下载PDF
An approximation to the P-wave reflection coefficient for amplitude variation with long-offset seismic data 被引量:1
11
作者 Wang Pu Zhang Wenpo Hu Tianyue 《Applied Geophysics》 SCIE CSCD 2007年第1期29-36,共8页
In recent years, long-offset exploration has been widely used, especially on marine seismic surveys. Conventional AVO analysis is insufficient for long-offset seismic data. To widen the application range of AVO analys... In recent years, long-offset exploration has been widely used, especially on marine seismic surveys. Conventional AVO analysis is insufficient for long-offset seismic data. To widen the application range of AVO analysis, we present a new P-wave reflection coefficient approximation applicable to long-offset data. Our result is similar to the well known Shuey formula which can be treated as an approximation to our results for short-offset seismic data. 展开更多
关键词 AVO long-offset Zoeppritz equations poisson's ratio.
下载PDF
P-kernel Normal Systems in Weakly P-inversive Semigroups 被引量:1
12
作者 CHEN Qian-hua FAN Xing-kui 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第2期171-177,共7页
In this paper, we first give the concept of weakly P-inversive semigroup S(P). Then we describe the strong P-congruences on S(P) in terms of their P-kernel normal systems. It is proved that there is a bijection be... In this paper, we first give the concept of weakly P-inversive semigroup S(P). Then we describe the strong P-congruences on S(P) in terms of their P-kernel normal systems. It is proved that there is a bijection between the strong P-congruences and the P-kernel normal systems. Finally, it is also prove that the lattice of strong P-congruences and the lattice of P-kernel normal systems on S(P) are isomorphic. 展开更多
关键词 weakly p-inversive semigroup strong p-congruence p-kernel normal system lattice isomorphism
下载PDF
Development of Instantaneous Hot Water Dispenser Based on Water Source Heat Pump
13
作者 Satoshi Yoshida Ryozo Ooka +1 位作者 Toshiyuki Hino Kazuo Kodama 《Journal of Energy and Power Engineering》 2014年第10期1703-1711,共9页
Natural energy use is important to reduce the energy consumption of buildings. However, further reducing energy consumption with traditional systems is difficult. Therefore, we proposed a MMHP (multi-source and multi... Natural energy use is important to reduce the energy consumption of buildings. However, further reducing energy consumption with traditional systems is difficult. Therefore, we proposed a MMHP (multi-source and multi-use heat pump) to achieve higher efficiency than traditional systems. The MMHP system connects multiple heat sources such as solar heat, the ground, and air and multiple heat uses such as cooling, heating, and a hot water dispenser with a water loop. Each type of heat use side can utilize heat efficiently. However, there is a distinct lack of highly efficient hot water dispensers available. Therefore, we developed the IHWD WS (instantaneous hot water dispenser based on a water source) heat pump. In this study, we developed a prototype of the IHWD WS heat pump. The coefficient of performance of the IHWD WS heat pump was 5.2-8.5 throughout a year. When it is improved, COP (coefficient of performance) is expected to be 9.3-9.9. 展开更多
关键词 Heat pumps hot water EFFICIENCY COp ground source.
下载PDF
An analytical p-y curve method based on compressive soil pressure model in sand soil 被引量:1
14
作者 JIANG Jie FU Chen-zhi +2 位作者 WANG Shun-wei CHEN Chao-qi OU Xiao-duo 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第6期1987-2004,共18页
With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of... With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of the pile within an allowable displacement is an important issue.However,the current p-y curve methods cannot fully take into account the pile-soil interaction,which will lead to a large calculation difference.In this paper,a new analytical p-y curve is established and a finite difference method for determining the lateral response of pile is proposed,which can consider the separation effect of pile-soil interface and the coefficient of circumferential friction resistance.In particular,an analytical expression is developed to determine the compressive soil pressure by dividing the compressive soil pressure into two parts:initial compressive soil pressure and increment of compressive soil pressure.In addition,the relationship between compressive soil pressure and horizontal displacement of the pile is established based on the reasonable assumption.The correctness of the proposed method is verified through four examples.Based on the verified method,a parametric analysis is also conducted to investigate the influences of factors on lateral response of the pile,including internal friction angle,pile length and elastic modulus of pile. 展开更多
关键词 laterally loaded piles compressive soil pressure model separation effect of pile-soil interface coefficient of circumferential friction resistance analytical p-y curve finite difference method
下载PDF
Intensification of Deep Hydrodesulfurization Through a Two-stage Combination of Monolith and Trickle Bed Reactors 被引量:1
15
作者 许闵 刘辉 +1 位作者 季生福 李成岳 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第8期888-897,共10页
Deep hydrodesulfurization (HDS) is an important process to produce high quality liquid fuels with ultra-low sul- fur. Process intensification for deep HDS could be implemented by developing new active catalysts and/... Deep hydrodesulfurization (HDS) is an important process to produce high quality liquid fuels with ultra-low sul- fur. Process intensification for deep HDS could be implemented by developing new active catalysts and/or new types of reactors. In this work, the kinetics of dibenzothiophene (DBT) hydrodesulfurization over Ni-P/SBA-15/ cordierite catalyst was investigated at 340-380 ℃ and 3.0-5.0 MPa. The first-order reaction model with respect to both DBT and H2 was used to fit the kinetics data in a batch recycle operation system. It is found that both the activation energy and rate constant over the Ni-P monolithic catalyst under our operating conditions are close to those over conventionally used HDS catalysts. Comparative performance studies of two types of reactors, i.e., trickle bed reactor and monolithic reactor, were performed based on reactor modeling and simulation. The results indicate that the productivity of the monolithic reactor is 3 times higher than that of the trickle bed reactor on a catalyst weight basis since effective utilization of the catalyst is higher in the monolithic reactor, but the volumetric productivity of the monolithic reactor is lower for HDS of DBT. Based on simulation results, a two- reactor-in-series configuration for hydrodesulfurization is proposed, in which a monolithic reactor is followed by a tickled bed reactor so as to attain intensified performance of the system converting fuel oil of different sulfur-containing compounds. It is illustrated that the two reactor scheme outperforms the trickle bed reactor both on reactor volume and catalyst mass bases while the content of sulfur is reduced from 200 μg·g-1 to about 10 μ·g-1. 展开更多
关键词 Hydrodesulfurization (HDS) Kinetics Mass transfer Monolithic reactor Trickle bed reactor Reactor modeling
下载PDF
标准参照测验决策一致性指标研究的总结与展望 被引量:10
16
作者 陈平 李珍 +1 位作者 辛涛 高慧健 《心理发展与教育》 CSSCI 北大核心 2011年第2期210-215,共6页
决策一致性指考生在两次平行测验中被一致归类的程度,是衡量标准参照测验质量的重要指标。到目前为止,基于经典测量模型和项目反应模型,研究者已经提出了数十种估计决策一致性指标的方法,并对这些方法的优劣进行了比较。由于模型基础和... 决策一致性指考生在两次平行测验中被一致归类的程度,是衡量标准参照测验质量的重要指标。到目前为止,基于经典测量模型和项目反应模型,研究者已经提出了数十种估计决策一致性指标的方法,并对这些方法的优劣进行了比较。由于模型基础和对分数分布的假设不同,各种方法适用于不同的测验情境。未来的研究应当对已有方法进行验证,并探讨决策一致性在教育测量中的应用途径,为教育和心理测量工作者估计测验的决策一致性指标提供凭据。 展开更多
关键词 决策一致性 信度 p系数 Kappa系数
下载PDF
甘肃博峪河自然保护区土壤纤毛虫群落特征 被引量:1
17
作者 宁应之 王红军 +1 位作者 王晓景 杜海峰 《西北师范大学学报(自然科学版)》 CAS 北大核心 2011年第2期87-94,共8页
用活体观察和蛋白银染色法对甘肃博峪河自然保护区11个采样点的土壤纤毛虫群落特征进行了研究.共鉴定到76种纤毛虫,隶属于3纲10目29科42属.广布种为陆生拟裸口虫(Pseudoholophrya terricola)、僧帽肾形虫(Colpoda cucullus)、齿脊拟肾形... 用活体观察和蛋白银染色法对甘肃博峪河自然保护区11个采样点的土壤纤毛虫群落特征进行了研究.共鉴定到76种纤毛虫,隶属于3纲10目29科42属.广布种为陆生拟裸口虫(Pseudoholophrya terricola)、僧帽肾形虫(Colpoda cucullus)、齿脊拟肾形虫(Paracolpoda steini)、膨胀肾形虫(Colpoda inflata)、土壤肾形虫(Colpodaedaphoni)、有肋薄咽虫(Leptopharynx costatus)、刚毛胃纤虫(Homalogastra setosa)、近亲殖口虫(Gonostomumaffine)、苔藓游仆虫(Euplotes muscicola).下毛目为该保护区土壤纤毛虫群落中的优势类群,肾形目和前口目为次优势类群,管口目和寡毛目属罕见类群.研究区C/P系数为0.615,Jaccard相似性系数在0.184~0.532之间.结果分析表明,博峪河自然保护区的生境适宜于土壤纤毛虫的生长与繁殖,各样点土壤纤毛虫物种分布有明显差异,且与各样点小生境密切相关,物种数的差异和较低的Jaccard相似性系数显示出土壤纤毛虫群落分布的异质性具有区块特征. 展开更多
关键词 土壤纤毛虫 群落特征 C/p系数 异质性 甘肃博峪河自然保护区
下载PDF
保安湖麦穗鱼种群生物学V.生产力 被引量:12
18
作者 张堂林 崔奕波 +2 位作者 方榕乐 谢松光 李钟杰 《水生生物学报》 CAS CSCD 北大核心 2001年第4期331-337,共7页
在 1 995年 1 0月至 1 996年 1 1月 ,依据有关种群参数估算了保安湖 1 # 试验围拦中麦穗鱼的生产力。月平均瞬时生长率的变化与年龄和季节有关 ,随着年龄增加生长率降低 ,在生活史的早期阶段生长最快 ,生长率一般在春、夏季较高。在研... 在 1 995年 1 0月至 1 996年 1 1月 ,依据有关种群参数估算了保安湖 1 # 试验围拦中麦穗鱼的生产力。月平均瞬时生长率的变化与年龄和季节有关 ,随着年龄增加生长率降低 ,在生活史的早期阶段生长最快 ,生长率一般在春、夏季较高。在研究期间 ,种群平均生物量为1 8 2 7kg·hm- 2 ,周年生产力为 36 53kg·hm- 2 ·a- 1 ,P/B系数为 2 0。 1 996世代对总生产力的贡献为 67 9%。种群月平均生物量及生产力均表现出了较明显的季节变化 ,生物量在秋季(9月 )出现峰值 ,生产力在冬季非常低 ,在夏季 (7月 )出现峰值 ,夏季生产力占总生产力的77 6%。 展开更多
关键词 麦穗鱼 生产力 p√B系数 种群 湖泊 鱼类群落
下载PDF
底栖动物次级生产力研究的理论与方法 被引量:75
19
作者 龚志军 谢平 阎云君 《湖泊科学》 EI CAS CSCD 2001年第1期79-88,共10页
底栖动物是淡水生态系统的一个主要组成部分 ,在渔业和环境科学上均有重要的理论意义和广泛的应用前景 .本文综述了国外在底栖动物次级生产力研究中的理论和方法 ,重点阐述了底栖动物次级生产力的计算方法、P/B系数、生产量以及影响次... 底栖动物是淡水生态系统的一个主要组成部分 ,在渔业和环境科学上均有重要的理论意义和广泛的应用前景 .本文综述了国外在底栖动物次级生产力研究中的理论和方法 ,重点阐述了底栖动物次级生产力的计算方法、P/B系数、生产量以及影响次级生产力的因素 ,并总结了目前该领域的一些新进展 ,以期为国内相关研究提供参考和借鉴 . 展开更多
关键词 底栖动物 次级生产力 p/B系数 体长频率法 水生态系统
下载PDF
武汉东湖铜锈环棱螺的种群动态及次级生产力 被引量:10
20
作者 龚志军 李艳玲 谢平 《湖泊科学》 EI CAS CSCD 北大核心 2009年第3期401-407,共7页
1999年6月至2000年5月对武汉东湖铜锈环棱螺的种群生态学进行了周年研究.铜锈环棱螺年均密度和生物量分别为92.2ind./m2和142.83g/m2,密度和生物量的高峰分别出现在6月(157ind./m2)和11月(205.78g/m2);东湖铜锈环棱螺为一年一代,其一年... 1999年6月至2000年5月对武汉东湖铜锈环棱螺的种群生态学进行了周年研究.铜锈环棱螺年均密度和生物量分别为92.2ind./m2和142.83g/m2,密度和生物量的高峰分别出现在6月(157ind./m2)和11月(205.78g/m2);东湖铜锈环棱螺为一年一代,其一年中种群含有5个年龄组,其中1998年龄组占绝对优势.利用瞬时增长率法计算东湖铜锈环棱螺的周年生产量带壳湿重为91.56g/m2,去壳干重为5.32g/m2,P/B系数为0.64.同时研究了铜锈环棱螺的生产力动态变化,其生产量累积多数季节均有发生,且以1998年龄组占优. 展开更多
关键词 武汉东湖 铜锈环棱螺 生产量 p/B系数
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部