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一类解析函数的极值问题
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作者 赵翠新 李书海 《山东师范大学学报(自然科学版)》 CAS 2010年第1期48-50,共3页
利用算子引进了新解析函数类Tμγ^m(α,β;A,B),利用微分从属关系得到系数估计、偏差定理、覆盖性质、单叶半径、凸半径以及极值点等性质.推广了文献中的相应结论.
关键词 系数估计 偏差定理 覆盖性质 单叶半径 凸半径
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动态载荷时域识别的级数方法 被引量:28
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作者 张方 朱德懋 《振动工程学报》 EI CSCD 1996年第1期1-8,共8页
以动力学基本理论为基础,推导了在实模态和复模态空间内载荷识别的级数系数平衡法,并以幂级数展开理论获得动态载荷识别的计算公式,将时域中的卷积关系近似简化为一个线性关系。数值仿真计算表明,这种方法适用于各种正弦、三角等波形的... 以动力学基本理论为基础,推导了在实模态和复模态空间内载荷识别的级数系数平衡法,并以幂级数展开理论获得动态载荷识别的计算公式,将时域中的卷积关系近似简化为一个线性关系。数值仿真计算表明,这种方法适用于各种正弦、三角等波形的时域载荷,尤其对在共振频率下的正弦激振力,利用其过渡响应可满意地进行识别。因此,这是一种值得工程推广的载荷识别方法。 展开更多
关键词 动态载荷 时域辨识 载荷识别 结构动力学
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多指标综合评价中权系数确定的一种综合分析方法 被引量:169
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作者 王明涛 《系统工程》 CSCD 1999年第2期56-61,共6页
本文分析了确定多指标综合评价中权系数的方法——主观赋权法和客观赋权法的基本原理与不足之处,提出了权系数确定的基本原则及一种综合分析方法,并通过实例说明这种方法的合理性.
关键词 综合评价 赋权法 权系数 经济效益
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ANNUAL DISTRIBUTION FEATURES OF PRECIPITATION IN CHINA AND THEIR INTERANNUAL VARIATIONS 被引量:130
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作者 张录军 钱永甫 《Acta meteorologica Sinica》 SCIE 2003年第2期146-163,共18页
The hierarchy and definition of the precipitation-concentration degree and precipitation- concentration period of annual precipitation have been proposed by using the so-called vector method of annual distribution of ... The hierarchy and definition of the precipitation-concentration degree and precipitation- concentration period of annual precipitation have been proposed by using the so-called vector method of annual distribution of precipitation,so that the two relevant parameters can represent the annual distribution of total precipitation correctly and indeed accurately.The relationship between the spatial and temporal distribution patterns and variations of the two parameters and the annual precipitation amount in China has been further investigated.Results demonstrate that the precipitation-concentration degree and the precipitation-concentration period increase from southeast to northwest gradually.Moreover there obviously exists a belt pattern:the largest variability of the precipitation-concentration degree and the precipitation-concentration period occurs in the Yellow River Valley and the middle and lower reaches of the Yangtze River, corresponding to the significant zones in which flood and drought take place frequently.It is found that there exist high correlations between the precipitation-concentration degree and precipitation- concentration period and the annual precipitation amount in Northeast China,North China,the middle and lower reaches of the Yangtze River. Furthermore,8-year and 22-year periodic oscillations in the precipitation-concentration degree and 6-year and 12-year cycles in the precipitation-concentration period are identified by use of their Morlet wavelet analysis. 展开更多
关键词 precipitation-concentration degree (PCD) precipitation-concentration period (PCP) spatial and temporal distribution climate changes climate trend coefficient
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由地基微波辐射计测量得到的北京地区水汽特性的初步分析 被引量:98
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作者 刘红燕 王迎春 +3 位作者 王京丽 李炬 曹晓彦 熊斌 《大气科学》 CSCD 北大核心 2009年第2期388-396,共9页
首先对比分析了三种测量水汽技术(地基微波辐射计、探空、GPS)之间的差异,得到地基微波辐射计与探空的差值为0.281cm,GPS与探空的差值为0.728cm,地基微波辐射计与GPS的差值为0.322cm。接着就地基12通道微波辐射计测量得到的水汽总量(简... 首先对比分析了三种测量水汽技术(地基微波辐射计、探空、GPS)之间的差异,得到地基微波辐射计与探空的差值为0.281cm,GPS与探空的差值为0.728cm,地基微波辐射计与GPS的差值为0.322cm。接着就地基12通道微波辐射计测量得到的水汽总量(简称PWV),分析了北京地区水汽在四个季节中的日变化特征。秋季日变化差为0.162cm,冬季日变化差为0.130cm,春季日变化差为0.229cm,夏季日变化差为0.276cm。另外,北京地区四个季节中水汽最大值/最小值出现频率最高的时间段呈现一定的特征。即四个季节中在北京时间00:00到00:59和23:00到23:59这两个时间段中,水汽出现最大值/最小值的概率较其他时间段都高,其中冬季在北京时间10:00到10:59之间出现最小值的概率最高。水汽总量PWV每小时变化率在四个季节中都存在这样的现象:出现正的水汽总量PWV每小时变化率的百分比与出现负的水汽总量PWV每小时变化率的百分比相当,几乎都为50%。最后就水汽与温度相关性做了分析,分别得到四个季节中各个小时水汽与温度的相关系数,结果显示各个小时水汽与温度的相关性在四个季节中,除了夏季从北京时间09:00到22:00为负相关外,其他时间段内都为正相关。而且各个小时水汽与温度的相关系数都按照秋、春、冬、夏的顺序递减。 展开更多
关键词 地基微波辐射计 水汽 日变化特征 温度 相关系数
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基于GIS的土壤侵蚀与土地利用关系分析 被引量:44
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作者 邹亚荣 张增祥 +2 位作者 周全斌 刘斌 王百川 《水土保持研究》 CSCD 2002年第1期67-69,75,共4页
土壤侵蚀分布与土地利用类型分布之间存在密切关系。以我国水蚀区广东惠东区为例 ,以 TM影像为主要数据源 ,在 GIS环境下 ,进行土壤侵蚀与土地利用类型的矢量分析 ,通过 SPSS软件包的统计分析 ,得出土地利用类型与土壤侵蚀的分布相关关... 土壤侵蚀分布与土地利用类型分布之间存在密切关系。以我国水蚀区广东惠东区为例 ,以 TM影像为主要数据源 ,在 GIS环境下 ,进行土壤侵蚀与土地利用类型的矢量分析 ,通过 SPSS软件包的统计分析 ,得出土地利用类型与土壤侵蚀的分布相关关系 ,其程度依次为林地、耕地、草地、城镇。 展开更多
关键词 GIS 土壤侵蚀 土地利用 遥感 类型 相关系数
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Black carbon aerosols and their radiative properties in the Pearl River Delta region 被引量:60
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作者 WU Dui MAO JieTai +9 位作者 DENG XueJiao TIE XueXi ZHANG YuanHang ZENG LiMin LI Fei TAN HaoBo BI XueYan HUANG XiaoYing CHEN Jing DENG Tao 《Science China Earth Sciences》 SCIE EI CAS 2009年第8期1152-1163,共12页
The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. He... The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main results are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1―14.8 μg·m-3 and the concentration decreases by about 1 μg·m-3 in average over the four years; It is higher in the dry season with a multi-year mean of 8.9 μg/m3 and lower in the rainy season with a multi-year mean of 8.0 μg·m-3; The extreme maximum of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, and a 4-year mean is 8.4 μg·m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 68% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher altitude station (Panyu) is consistently lower than 展开更多
关键词 PEARL River Delta BC AEROSOLS SCATTERING coefficient absorption coefficient single SCATTERING ALBEDO
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Dirichlet级数表示的整函数的增长性 被引量:49
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作者 高宗升 deptg.buaa.edu.cn 《数学学报(中文版)》 SCIE CSCD 北大核心 1999年第4期741-748,共8页
本文系统地研究了在全平面上收敛的Dirichlet级数的增长性,得到了级数的系数和增长级之间关系的一系列充要条件.
关键词 级数 型函数 增长性 狄利克雷级数 整函数
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大孔混凝土组成设计及路用性能 被引量:46
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作者 郑木莲 王秉纲 胡长顺 《长安大学学报(自然科学版)》 EI CAS CSCD 北大核心 2003年第4期6-10,共5页
提出了路面大孔混凝土排水基层材料的配合比设计方法。试验表明其有较高的强度及排水能力。通过试验及机理分析得出其具有较小的温度及干燥收缩性、良好的抗冻性等路用性能。
关键词 组成设计 路用性能 大孔混凝土 配合比 强度 空隙率 渗透系数 收缩性 抗冻性 公路 路面基层
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Fractional differential approach to detecting textural features of digital image and its fractional differential filter implementation 被引量:50
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作者 PU YiFei WANG WeiXing +2 位作者 ZHOU JiLiu WANG YiYang JIA HuaDing 《Science in China(Series F)》 2008年第9期1319-1339,共21页
This paper mainly discusses fractional differential approach to detecting textural features of digital image and its fractional differential filter. Firstly, both the geo- metric meaning and the kinetic physical meani... This paper mainly discusses fractional differential approach to detecting textural features of digital image and its fractional differential filter. Firstly, both the geo- metric meaning and the kinetic physical meaning of fractional differential are clearly explained in view of information theory and kinetics, respectively. Secondly, it puts forward and discusses the definitions and theories of fractional stationary point, fractional equilibrium coefficient, fractional stable coefficient, and fractional grayscale co-occurrence matrix. At the same time, it particularly discusses frac- tional grayscale co-occurrence matrix approach to detecting textural features of digital image. Thirdly, it discusses in detail the structures and parameters of nxn any order fractional differential mask on negative x-coordinate, positive x-coordi- nate, negative y-coordinate, positive y-coordinate, left downward diagonal, left upward diagonal, right downward diagonal, and right upward diagonal, respectively. Furthermore, it discusses the numerical implementation algorithms of fractional differential mask for digital image. Lastly, based on the above-mentioned discus- sion, it puts forward and discusses the theory and implementation of fractional differential filter for digital image. Experiments show that the fractional differential-based image operator has excellent feedback for enhancing the textural details of rich-grained digital images. 展开更多
关键词 fractional stationary point fractional equilibrium coefficient fractional stable coefficient fractional grayscale co-occurrence matrix fractional differential mask
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Endoscopic ultrasound elastography for evaluation of lymph nodes and pancreatic masses:A multicenter study 被引量:48
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作者 Marc Giovannini Botelberge Thomas +16 位作者 Bories Erwan Pesenti Christian Caillol Fabrice Esterni Benjamin Monges Geneviève Arcidiacono Paolo Deprez Pierre Yeung Robert Schimdt Walter Schrader Hanz Szymanski Carl Dietrich Christoph Eisendrath Pierre Van Laethem Jean-Luc Devière Jacques Vilmann Peter Saftoiu Andrian 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第13期1587-1593,共7页
AIM:To evaluate the ability of endoscopic ultrasound(EUS) elastography to distinguish benign from malignant pancreatic masses and lymph nodes.METHODS:A multicenter study was conducted and included 222 patients who und... AIM:To evaluate the ability of endoscopic ultrasound(EUS) elastography to distinguish benign from malignant pancreatic masses and lymph nodes.METHODS:A multicenter study was conducted and included 222 patients who underwent EUS examination with assessment of a pancreatic mass(n=121) or lymph node(n=101).The classification as benign or malignant,based on the real time elastography pattern,was compared with the classif ication based on the B-mode EUS images and with the fi nal diagnosis obtained by EUS-guided fi ne needle aspiration(EUS-FNA) and/or by surgical pathology.An interobserver study was performed.RESULTS:The sensitivity and specificity of EUS elastography to differentiate benign from malignant pancreatic lesions are 92.3% and 80.0%,respectively,compared to 92.3% and 68.9%,respectively,for the conventional B-mode images.The sensitivity and specificity of EUS elastography to differentiate benign from malignant lymph nodes was 91.8% and 82.5%,respectively,compared to 78.6% and 50.0%,respectively,for the B-mode images.The kappa coefficient was 0.785 for the pancreatic masses and 0.657 for the lymph nodes.CONCLUSION:EUS elastography is superior compared to conventional B-mode imaging and appears to be able to distinguish benign from malignant pancreatic masses and lymph nodes with a high sensitivity,specificity and accuracy.It might be reserved as a second line examination to help characterise pancreatic masses after negative EUS-FNA and might increase the yield of EUS-FNA for lymph nodes. 展开更多
关键词 Endoscopic ultrasound Elasticity coefficient ELASTOGRAPHY Pancreatic mass Lymph node
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控制煤层气含量及可采性的主要地质因素 被引量:44
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作者 张胜利 陈晓东 《天然气工业》 EI CAS CSCD 北大核心 1997年第4期15-19,共5页
煤层含气量及煤层可采性是决定煤层气能否成藏的重要条件。研究表明,控制煤层气含量的主要地质因素有:煤变质程度,埋藏深度,煤层顶、底板岩性,以及断裂构造情况等,其中煤变质程度起着根本性作用。控制煤层气可采性的主要地质因素... 煤层含气量及煤层可采性是决定煤层气能否成藏的重要条件。研究表明,控制煤层气含量的主要地质因素有:煤变质程度,埋藏深度,煤层顶、底板岩性,以及断裂构造情况等,其中煤变质程度起着根本性作用。控制煤层气可采性的主要地质因素有:煤层渗透性、煤等温吸附特征及煤的含气饱和程度,其中煤层渗透率是最主要的影响因素。 展开更多
关键词 煤成气 含气量 可采性 渗透率 储集
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Improved BP Neural Network for Transformer Fault Diagnosis 被引量:42
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作者 SUN Yan-jing ZHANG Shen MIAO Chang-xin LI Jing-meng 《Journal of China University of Mining and Technology》 EI 2007年第1期138-142,共5页
The back propagation (BP)-based artificial neural nets (ANN) can identify complicated relationships among dissolved gas contents in transformer oil and corresponding fault types, using the highly nonlinear mapping nat... The back propagation (BP)-based artificial neural nets (ANN) can identify complicated relationships among dissolved gas contents in transformer oil and corresponding fault types, using the highly nonlinear mapping nature of the neural nets. An efficient BP-ALM (BP with Adaptive Learning Rate and Momentum coefficient) algorithm is proposed to reduce the training time and avoid being trapped into local minima, where the learning rate and the momentum coefficient are altered at iterations. We developed a system of transformer fault diagnosis based on Dissolved Gases Analysis (DGA) with a BP-ALM algorithm. Training patterns were selected from the results of a Refined Three-Ratio method (RTR). Test results show that the system has a better ability of quick learning and global convergence than other methods and a superior performance in fault diagnosis compared to convectional BP-based neural networks and RTR. 展开更多
关键词 transformer fault diagnosis BACK-PROPAGATION artificial neural network momentum coefficient
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Evaluation of diffusion weighted imaging of magnetic resonance imaging in small focal hepatic lesions:a quantitative study in 56 cases 被引量:39
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作者 Xian-Yue Quan, Xi-Jie Sun, Zhi-Jian Yu and Ming Tang Imaging Center, Affiliated Zhujiang Hospital of Southern Medical University, Guangzhou 510282, China 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2005年第3期406-409,共4页
Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepat... Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepatic lesions less than 3 cm in diameter by the quantitation of apparent diffusion coefficient (ADC) values. METHODS:DWI using 1.5T MRI scanner unit was performed with a spin-echo single-shot echo planar imaging (EPI) in 56 cases of small focal hepatic lesions, including hepatocellular carcinoma (11), hepatic metastatic tumor (15 ), hepatic cavernous hemangioma (14), and hepatic cyst (16).The ADC values of these lesions were calculated respectively. The ratios of the ADC values of lesion/liver in hepatocellular carcinomas and hepatic metastatic tumors were also estimated. RESULTS:The mean ADC values (mm2/s) were (0.93±0.06) ×10-3 in hepatocellular carcinomas, (1.09±0.18)×10-3 in hepatic metastatic tumors,(1.95±0.38)×10-3 in hepatic cavernous hemangiomas, and (3.18±0.33) ×10-3 in hepatic cysts. The ratios of ADC values of lesion/liver were 0.90±0.06 and 1.15±0.14 in hepatocellular carcinoma and hepatic metastatic tumors respectively, which were significantly different (P<0.05). CONCLUSION:The measurement of ADC values and the ratios of ADC values of lesion/liver are helpful in MR diagnosis and differentiation of focal hepatic lesions. 展开更多
关键词 quantitative study diffusion-weighted imaging apparent diffusion coefficient magnetic resonance imaging b value
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Role of diffusion-weighted magnetic resonance imaging in the differential diagnosis of focal hepatic lesions 被引量:38
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作者 Naoto Koike Akihiro Cho +4 位作者 Katsuhiro Nasu Kazuhiko Seto Shigeyuki Nagaya Yuji Ohshima Nobuhiro Ohkohchi 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第46期5805-5812,共8页
AIM: To evaluate the utility of diffusion-weighted imaging (DWl) in screening and differential diagnosis of benign and malignant focal hepatic lesions. METHODS: Magnetic resonance imaging (MRI) examinations were... AIM: To evaluate the utility of diffusion-weighted imaging (DWl) in screening and differential diagnosis of benign and malignant focal hepatic lesions. METHODS: Magnetic resonance imaging (MRI) examinations were performed using the Signa Excite Xl Twin Speed 1.5T system (GE Healthcare, Milwaukee, Wl, USA). Seventy patients who had undergone MRI of the liver [29 hepatocellular carcinomas (HCC), four cholangiocarcinomas, 34 metastatic liver cancers, 10 hemangiomas, and eight cysts] between April 2004 and August 2008 were retrospectively evaluated. Visualization of lesions, relative contrast ratio (RCR), and apparent diffusion coefficient (ADC) were compared between benign and malignant lesions on DWl. Su- perparamagnetic iron oxide (SPIO) was administered to 59 patients, and RCR was compared pre- and postadministration.RESULTS: DWI showed higher contrast between malignant lesions (especially in multiple small metastatic cancers) and surrounding liver parenchyma than did contrast-enhanced computed tomography. ADCs (mean±SD × 10^-3 mm2/s) were significantly lower (P 〈 0.05) in malignant lesions (HCC: 1.31 ± 0.28 and liver metastasis: 1.11 ± 0.22) and were significantly higher in benign lesions (hemangioma: 1.84 ± 0.37 and cyst: 2.61 ± 0.45) than in the surrounding hepatic tissues. RCR between malignant lesions and surrounding he- patic tissues significantly improved after SPIO administration, but RCRs in benign lesions were not improved.CONCLUSION: DWI is a simple and sensitive method for screening focal hepatic lesions and is useful for differential diagnosis. 展开更多
关键词 Hepatic tumor Liver imaging Magneticresonance imaging Diffusion-weighted imaging Apparent diffusion coefficient
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Evaluation of the suitability of a partially defatted black soldier fly (Hermetia illucens L.) larvae meal as ingredient for rainbow trout (Oncorhynchus mykiss Walbaum) diets 被引量:36
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作者 M. Renna A. Schiavone +11 位作者 F. Gai S. Dabbou C. Lussiana V. Malfatto M. Prearo M. T. Capucchio I. Biasato E. Biasibetti M. De Marco A. Brugiapaglia I. Zoccarato L. Gasco 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2017年第4期957-969,共13页
Background: Two trials were performed to evaluate a partially defatted Hermetia illucens(HI) larvae meal as potential feed ingredient in rainbow trout(Oncorhynchus mykiss Walbaum) diets. In the first trial, 360 trout(... Background: Two trials were performed to evaluate a partially defatted Hermetia illucens(HI) larvae meal as potential feed ingredient in rainbow trout(Oncorhynchus mykiss Walbaum) diets. In the first trial, 360 trout(178.9 ± 9.8 g of mean initial body weight) were randomly divided into three experimental groups(4 tanks/treatment, 30 fish/tank). The fish were fed for 78 days with isonitrogenous, isolipidic and isoenergetic diets containing increasing levels of HI, on as fed basis: 0%(HI0, control diet), 25%(HI25) and 50%(HI50) of fish meal substitution, corresponding to dietary inclusion levels of 0, 20% and 40%. In the second trial, 36 trout(4 tanks/treatment, 3 fish/tank) were used to evaluate the in vivo apparent digestibility coefficients(ADC) of the same diets used in the first trial.Results: Survival, growth performance, condition factor, somatic indexes, and dorsal fillet physical quality parameters were not affected by diet. The highest dietary inclusion of HI larvae meal increased dry matter and ether extract contents of trout dorsal fillet. The use of HI larvae meal induced a decrease of valuable polyunsaturated fatty acids(PUFA) even if differences were only reported at the highest level of HI inclusion. The insect meal worsened the lipids health indexes of the same muscle. Dietary inclusion of insect meal did not alter the villus height of the fish. No differences were found among treatments in relation to ADC of ether extract and gross energy, while ADC of dry matter and crude protein were higher in HI25 if compared to HI50.Conclusions: The obtained results showed that a partially defatted HI larvae meal can be used as feed ingredient in trout diets up to 40% of inclusion level without impacting survival, growth performance, condition factor, somatic indexes, dorsal fillet physical quality parameters, and intestinal morphology of the fish. However, further investigations on specific feeding strategies and diet formulations are needed to limit the observed negative effects of the insect meal on the FA 展开更多
关键词 Animal performance Apparent DIGESTIBILITY coefficient Carnivorous fish Fatty acids FISHMEAL substitution Insect MEAL
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沁水盆地南部煤层气勘探成果与地质分析 被引量:33
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作者 樊生利 《天然气工业》 EI CAS CSCD 北大核心 2001年第4期35-38,共4页
沁水盆地南部地区已累计投入 40口井的勘探工作量 ,并取得了重大的勘探成果 ,证实该区为煤层气高渗富集区。从含煤性、含气性、可采性等方面对该区进行了全面分析 ,得出以下认识 :煤层厚度较大 ,分布稳定 ;煤变质程度高 ,煤的吸附能力... 沁水盆地南部地区已累计投入 40口井的勘探工作量 ,并取得了重大的勘探成果 ,证实该区为煤层气高渗富集区。从含煤性、含气性、可采性等方面对该区进行了全面分析 ,得出以下认识 :煤层厚度较大 ,分布稳定 ;煤变质程度高 ,煤的吸附能力强 ,含气量高 ,含气饱和度也较高 ;煤体结构、煤岩类型和煤质好 ,煤层割理较发育 ,渗透性较好 ,适合于压裂改造 ;区域构造稳定 ,煤系及上覆连续地层保存较好 ,后期改造、断裂不严重 ,构造较简单 ,煤层气赋存和保存条件好 ;煤层埋藏较浅 ;水文地质条件比较有利。综合评价该区煤层气具有良好的可采性 ,可以作为我国第一个煤层气滚动勘探开发区块。 展开更多
关键词 沁水盆地 煤成气 勘探成果 勘探评价 滚动开发 地质分析
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定向井中摩擦阻力模式及其应用的初步研究 被引量:29
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作者 张建群 孙学增 赵俊平 《大庆石油学院学报》 CAS 北大核心 1989年第4期23-28,共6页
本文以约翰西克等人提出的摩擦阻力综合参数模式为基础,考虑了钻柱拉力与钻柱所受侧向力具有相关性这一因素,建立了更符合实际情况的摩擦阻力模式,根据此模式结合大庆油田中区所钻定向井的实际情况,对其摩擦系数值进行了初步确定,并对... 本文以约翰西克等人提出的摩擦阻力综合参数模式为基础,考虑了钻柱拉力与钻柱所受侧向力具有相关性这一因素,建立了更符合实际情况的摩擦阻力模式,根据此模式结合大庆油田中区所钻定向井的实际情况,对其摩擦系数值进行了初步确定,并对巳知泥浆性能、钻具组合和井斜资料的定向井进行了摩阻拉力和转矩损失的预测分析。 展开更多
关键词 定向井 摩擦阻力 模式 油田 钻井
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盘形滚刀刀间距对岩石跃进破碎参数的影响 被引量:31
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作者 纪昌明 张照煌 叶定海 《应用基础与工程科学学报》 EI CSCD 2008年第2期255-263,共9页
正确确定岩石的性能参数是全断面岩石掘进机使用及高性能全断面岩石掘进机研制的理论基础.通过盘形滚刀不同刀间距的压痕试验,研究了不同岩石上刀间距对盘形滚刀跃进破碎参数的影响,从而发现,盘形滚刀与北京昌平花岗岩相互作用时,岩石... 正确确定岩石的性能参数是全断面岩石掘进机使用及高性能全断面岩石掘进机研制的理论基础.通过盘形滚刀不同刀间距的压痕试验,研究了不同岩石上刀间距对盘形滚刀跃进破碎参数的影响,从而发现,盘形滚刀与北京昌平花岗岩相互作用时,岩石发生第一次、第二次和第三次跃进破碎时盘形滚刀切深与刀间距高度线性相关,只在第一次跃进破碎时,盘形滚刀推力与刀间距高度线性相关;盘形滚刀与北京顺义大理岩相互作用时,岩石发生第一次跃进破碎时的跃进量与刀间距高度线性相关;盘形滚刀与山东掖县大理岩相互作用时,岩石发生第一次、第三次跃进破碎时,盘形滚刀推力不仅与刀间距高度线性相关,盘形滚刀跃进量与刀间距也高度线性相关. 展开更多
关键词 盘形滚刀 跃进破碎 参数 试件 全断面岩石掘进机
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Phosphate removal from wastewater by model-La(Ⅲ)zeolite adsorbents 被引量:31
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作者 NING Ping BART Hans-Jorg +2 位作者 LI Bing LU Xiwu ZHANG Yong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第6期670-674,共5页
Phosphorus is one of the primary nutrients which leads to eutrophication and accelerates aging process in enclosed water bodies. Because of the poor phosphorus selectivity of other adsorbents, the novel La(Ⅲ)-modif... Phosphorus is one of the primary nutrients which leads to eutrophication and accelerates aging process in enclosed water bodies. Because of the poor phosphorus selectivity of other adsorbents, the novel La(Ⅲ)-modified zeolite adsorbent (LZA) was prepared by modifying 90 nm zeolite with lanthanide to selectively remove phosphate in the presence of various omnipresent anions, such as sulfates, bicarbonates, and chlorides. Through batch and fixed bed operation, the following optimum conditions were obtained: concentration of lanthanum chloride solution 0.05 mol/L; solid/liquor ratio 1/25; pH 10; calcination temperature 550℃; time 1 h. The value of the Freundlich model constants Kf and 1/n were found to be 16.76 mg/L and 0.2209, respectively. In addition, when calculated at pH 6.0, distribution coefficient KD could be as high as 36.6. Furthermore, in the alkaline pH range, solution of 0.8 mol/L NaCl was used to regenerate the saturated LZA, which could reach the high regeneration efficiency as high as 100%. Because of the good selectivity and regenerability of LZA, it might serve as a potential way for advanced phosphate removal from the sewage containing other anions. 展开更多
关键词 PHOSPHATE adsorption ZEOLITE regeneration distribution coefficient
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