期刊文献+
共找到10,681篇文章
< 1 2 250 >
每页显示 20 50 100
Overview of Precious Metal Content Analysis Methods in Automotive Catalytic Converter 被引量:1
1
作者 Xianpeng Yang Chengbao Xie +4 位作者 Ning Liu Xin Du Suqing Wang Huasheng Jiang Zhengang Zhang 《Journal of Materials Science and Chemical Engineering》 2023年第11期7-14,共8页
With the increasing awareness of environmental protection, people’s concern of pollution issues arising. Vehicles, as the most important means of transportation, its exhaust emission has received considerable attenti... With the increasing awareness of environmental protection, people’s concern of pollution issues arising. Vehicles, as the most important means of transportation, its exhaust emission has received considerable attention. The catalytic converter is able to purify harmful substances in exhaust gas. The absolute content of precious metals in the catalytic converter dominates the exhaust gas purification effect. Accurate detection of precious metal content is of great significance for controlling the cost of catalysts, ensuring catalytic performance and recovering precious metals from spent catalysts. We herein summarized several instruments for precious metals content exploration, such as X-ray fluorescence spectrometer (XRF), atomic absorption spectrometer (AAS), inductively coupled plasma emission spectrometer (ICP) and spectrophotometer. In this thesis, the feasibility of using various devices for characterizing precious metal content in catalytic converters is analyzed and their strengths or weaknesses are elaborated. 展开更多
关键词 Catalytic Converter Precious Metal content Analysis methods
下载PDF
Total phenolic, flavonoid content, and antioxidant activity of flour, noodles, and steamed bread made from different colored wheat grains by three milling methods 被引量:9
2
作者 Yaoguang Li Dongyun Ma +4 位作者 Dexiang Sun Chenyang Wang Jian Zhang Yingxin Xie Tiancai Guo 《The Crop Journal》 SCIE CAS CSCD 2015年第4期328-334,共7页
The objective of this study was to evaluate the effects of wheat variety, food processing, and milling method on antioxidant properties. Black wheat variety Heibaoshi 1 had the highest total phenolic content(659.8 μg... The objective of this study was to evaluate the effects of wheat variety, food processing, and milling method on antioxidant properties. Black wheat variety Heibaoshi 1 had the highest total phenolic content(659.8 μg gallic acid equivalents g-1), total flavonoid content(319.3 μg rutin equivalents g-1), and antioxidant activity, whereas light purple wheat variety Shandongzimai 1 had the lowest total flavonoid content(236.2 μg rutin equivalents g-1) and antioxidant activity. Whole wheat flour and partially debranned grain flour had significantly higher total phenolic contents, total flavonoid contents, and antioxidant activity than refined flour(P < 0.05). Compared with flour, total phenolic contents, total flavonoid contents and antioxidant activity decreased in noodles and steamed bread, whereas noodles had slightly higher total phenolic and flavonoid content than steamed bread. Antioxidant activities(by ferric reducing ability of plasma assay) of steamed bread made from whole wheat flour, partially debranned grain flour, and refined flour were 23.5%, 21.1%, and 31.6% lower, respectively, than the corresponding values of flour. These results suggested that black whole wheat flour and partially debranned grain flour are beneficial to human health. 展开更多
关键词 TOTAL PHENOLIC content TOTAL flavonoid content Milling method Antioxidant activity COLORED wheat
下载PDF
Re-discussing the content of the prescription rights of midwives under certain circumstances using the Delphi method 被引量:1
3
作者 Shi-Fan Han Rui-Fang Zhu +1 位作者 Jin-Lian Cheng Xiao-Ding Yue 《Chinese Nursing Research》 CAS 2017年第3期146-150,共5页
Objective: This study sought to investigate the content of the prescription rights and the prescription types of midwives under certain circumstances in China. Methods: The Delphi method was used to consult 18 nursi... Objective: This study sought to investigate the content of the prescription rights and the prescription types of midwives under certain circumstances in China. Methods: The Delphi method was used to consult 18 nursing experts and 14 medical experts, A total of 30 experts finished the consulting. The reliability of the expert opinions was analyzed to determine the specific situations in which midwives may write prescriptions, the content of the prescription rights and the prescription types. Results: In six specific circumstances (uterine contraction fatigue, uterine contractions that are too strong, postpartum hemorrhage, premature rupture of the membranes, normal delivery and neonatal asphyxia), midwives have the right to prescribe and administer medication, including 20 drugs and 13 auxiliary examinations. Of these drugs and examinations, 51.5% of the drugs and adjuvant examination prescriptions tend to be independent prescriptions, 30.3% tend to be protocol prescriptions, and 18.2% are similar to both types. Conclusions: The midwives should be granted some prescription rights to enhance their autonomy and the professionalism of midwifery. 展开更多
关键词 Delphi method Midwife Specific circumstances Prescription content Prescription type
下载PDF
Comparing Two Methods for Measuring Soil Bulk Density and Moisture Content 被引量:1
4
作者 Jalal D. Jabro William B. Stevens William M. Iversen 《Open Journal of Soil Science》 2020年第6期233-243,共11页
<span style="font-family:Verdana;">Soil bulk density and moisture content are dynamic properties that vary with changes in soil and field conditions and have many agricultural, hydrological and environ... <span style="font-family:Verdana;">Soil bulk density and moisture content are dynamic properties that vary with changes in soil and field conditions and have many agricultural, hydrological and environmental implications. The main objective of this study was to compare between a soil core sampling method (core) and the CPN MC-3 Elite<span style="white-space:nowrap;"><sup>TM</sup></span> nuclear gauge method (radiation) for measuring bulk density (<span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"></span><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>ρ<sub>B</sub></i></span></span></i></span>) and volumetric moisture content (<span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>θ<span style="font-size:10.9091px;">v</span></i></span></span></i></span>) in a clay loam soil. Soil <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>ρ<sub>B</sub></i></span></span></i></span> and <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"></span><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>θ<span style="font-size:10.9091px;">v</span></i></span></span></i></span> measurements were determined using the core and radiation methods at 0 - 10 and 10 - 20 cm soil depths. The mean values of soil <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>ρ<sub>B</sub></i></span></span></i></span> obtained using the core method (1.454, 1.492 g<span style="color:#4F4F4F;font-family:" font-size:14px;white-space:normal;background-color:#f7f7f7;"="">·</span>cm<span style="white-space:nowrap;"><sup>&minus;3</sup></span>) were greater than those obtained using the radiation method (1.343, 1.476 g<span style="color:#4F4F4F;font-family:" font-size:14px;white-space:normal;background-color:#f7f7f7;"="">·</span>cm<span style="white-space:nowrap;"><sup>&minus;3</sup></span>) at the 0 - 10 and 10 - 20 cm depths, respectively. Mean <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>ρ<sub>B</sub></i></span></span></i></span> and <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>θ<span style="font-size:10.9091px;">v</span></i></span></span></i></span> values averaged across both depths (referred to as the 0 - 20 cm depth) measured by the core method were 4.47% and 22.74% greater, respectively, than those obtained by the radiation method. The coefficients of variation (CV) of soil <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"></span><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>ρ<sub>B</sub></i></span></span></i></span> values measured by the core method were lower than the CV values of those measured by the radiation method at both depths;however, the CV’s of <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>ρ<sub>B</sub></i></span></span></i></span> values for both methods were larger at the 0 - 10 cm depth than those measured at the 10 - 20 cm depth. Similarly, the CV values of soil <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>θ<sub>v</sub></i></span></span></i></span> values measured by the core method were lower than the CV values of those measured by the radiation method at both depths. There were significant differences between two methods in terms of <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>ρ<sub>B</sub></i></span></span></i></span> and <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>θ<sub>v</sub></i></span></span></i></span>, with the core method generating greater values than the radiation method at the 0 - 20 cm depth. These discrepancies between the two methods could have resulted from soil compaction and soil disturbance caused by the core and radiation techniques, respectively, as well as by other sources of error. Nevertheless, the core sampling method is considered the most common one for measuring <span style="white-space:nowrap;"><i><span style="font-family:Verdana;white-space:normal;"><span style="white-space:nowrap;"><i>ρ<sub>B</sub></i></span></span></i></span> for many agricultural, hydrological and environmental studies in most soils.</span> 展开更多
关键词 SOIL Bulk Density Moisture content Core method Radiation method
下载PDF
Synthesis of KNiF_3 with Lower Oxygen Content by Refluxing Method 被引量:1
5
作者 SHEN Hai-yun YANG Qiu-hua ZHAO Shao-jing WANG Dan 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2010年第2期178-180,共3页
The complex fluoride, KNiF3, with perovskite structure was synthesized by refluxing KF and Ni(NO3)2·6H20 in ethanediol. The samples were characterized by X-ray diffraction(XRD), transmission electron microsc... The complex fluoride, KNiF3, with perovskite structure was synthesized by refluxing KF and Ni(NO3)2·6H20 in ethanediol. The samples were characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), and ultraviolet-visible diffuse reflectance speetroseopy(UV-Vis DRS). The results indicate that the mean diameter of KNiF3 particles is about 30-60 nm and the oxygen content in the samples is ≤5%. The prepared KNiF3 shows obvious absorption peaks at 400-830 nm. 展开更多
关键词 KNiF3 Refluxing method Oxygen content
下载PDF
Nondestructive testing method of wood moisture content based on a planar capacitance sensor model 被引量:3
6
作者 WANG Jue LUO Yue-sheng LIU Shao-gang 《Forestry Studies in China》 CAS 2010年第3期142-146,共5页
For our research, a new hybrid experimental-computational method is presented. We applied a least squares fitting method (LSFM) to reconstruct the wood moisture content (WMC) from the data measured with a planar c... For our research, a new hybrid experimental-computational method is presented. We applied a least squares fitting method (LSFM) to reconstruct the wood moisture content (WMC) from the data measured with a planar capacitance sensor. A boundary element method (BEM) was used to compute the relationship between capacitance and the dielectric constant. A functional relationship between MC and the dielectric constant was identified by LSFM. The agreement of this final computation result with the experimental data indicates that this method can be used to estimate the WMC quickly and effectively with engineering analysis. Compared with popular statistical methods, a large number of experiments are avoided, some costs of testing are reduced and the efficiency of testing is enhanced. 展开更多
关键词 planar capacitance sensor nondestructive testing wood moisture content boundary element method least squares fitring method
下载PDF
Optimization of Coarse Aggregate Content based on Efficacy Coefficient Method 被引量:10
7
作者 汪振双 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第2期330-335,共6页
The influence of coarse aggregate content on concrete properties was investigated.From the perspective of Frame Concrete Theory,six groups concrete were produced with the same proportion except for coarse aggregate co... The influence of coarse aggregate content on concrete properties was investigated.From the perspective of Frame Concrete Theory,six groups concrete were produced with the same proportion except for coarse aggregate content,with coarse aggregate content of 0%,40%,50%,60%,75%,and 80%,respectively.Slump,compressive and flexural tensile strengths,elastic modulus,and water penetration were tested to research the effect of coarse aggregate content on concrete.The experimental results reveal that slump reduces with increasing of coarse aggregate content,while compressive strength,elastic modulus and flexural tensile strength increase with the coarse aggregate content increasing,and water penetration reduces with coarse aggregate content increasing before 75% then increased.Workability,strength,durability and economical indexes system were established to optimize the coarse aggregate content in concrete based on efficacy coefficient method.The optimization results show that when coarse aggregate content is 60%,the system efficacy coefficient reaches to 0.89,and it expresses the better comprehensive performance. 展开更多
关键词 coarse aggregate content WORKABILITY STRENGTH DURABILITY efficacy coefficient method
下载PDF
Deconvolution Method for Determination of the Nitrogen Content in Cellulose Carbamates
8
作者 Guang Mei CHEN Yi Ping HUANG 《Chinese Chemical Letters》 SCIE CAS CSCD 2001年第4期365-368,共4页
Cellulose carbamates (CC) were synthesized with microcrystalline cellulose as raw materials. The Fourier transform infrared spectra of CC with different nitrogen content were recorded. The accurate results of the nitr... Cellulose carbamates (CC) were synthesized with microcrystalline cellulose as raw materials. The Fourier transform infrared spectra of CC with different nitrogen content were recorded. The accurate results of the nitrogen content for CC can be obtained by using the deconvolution method when the nitrogen content is less than 3.5%. The relationship between the nitrogen content and the absorption intensity ratio of the corresponding separated absorption peaks in FTIR spectra has been expressed bg an equation precisely. 展开更多
关键词 Cellulose carbamates nitrogen content deconvolution method baseline method
下载PDF
Chemical Analysis Method for Magnesia and Magnesia-Alumina Refractories——Gravimetric-Molybdenum Blue Photometric Method for Determination of Silicon Dioxide Content 被引量:1
9
作者 Wang Jing 《China's Refractories》 CAS 2007年第1期39-41,共3页
This standard specifies the gravimetric-molybdenum blue photometric method for determination of silicon dioxide content.
关键词 Chemical Analysis method for Magnesia and Magnesia-Alumina Refractories Gravimetric-Molybdenum Blue Photometric method for Determination of Silicon Dioxide content
下载PDF
A Rapid Method for Measuring Seed Protein Content in Cowpea (<i>Vigna unguiculata</i>(L.) Walp) 被引量:1
10
作者 Yuejin Weng Ainong Shi +5 位作者 Waltram Second Ravelombola Wei Yang Jun Qin Dennis Motes David Octor Moseley Pengyin Chen 《American Journal of Plant Sciences》 2017年第10期2387-2396,共10页
Cowpea (Vigna unguiculata (L.) Walp), a legume crop that is grown in the worldwide, provides beneficial proteins for human consumption and animal feeding. In comparison, Rapid N analyzer as traditional method, has bee... Cowpea (Vigna unguiculata (L.) Walp), a legume crop that is grown in the worldwide, provides beneficial proteins for human consumption and animal feeding. In comparison, Rapid N analyzer as traditional method, has been widely used to measure protein content through the percentage of total nitrogen in the seed’s grounded powder. Near-Infrared Reflectance (NIR) has commonly been used to measure protein content in soybean seeds using whole grain without the need of seed grinding, which makes it possible to obtain fast results at a lower cost-per-analysis than the traditional combustion method. The specific objective of this study is to test a rapid method for measuring cowpea seed protein content by the NIR analyzer comparing to the traditional rapid N analyzer. A total of 240 cowpea genotypes were used in this study, including six seed coat colors, black, blackeye, browneye, cream, pinkeye, and red with 40 cowpea genotypes. The results showed that a linear relationship exists between the NIR analyzer and the Rapid N analyzer in the six different color groups. The correlation efficiency (r) between the seed protein contents from NIR and Rapid N was higher for pinkeye seed (r = 0.867), blackeye (0.771), cream (0.729), browneye (0.700), and red (0.623), respectively, but lower for black seeds, indicating that the NIR analyzer can be used to measure protein content for cowpea seeds with the five types of seed coat except black. Overview, the cowpea seed protein content measured from the NIR analyzer showed a little higher seed protein content. A series of regression models with different seed coat color have been built to adjust to protein content of colorful cowpea seeds from the NIR analyzer. But, it is not recommended to use for black color seeds due to a very low correlation efficiency (r) value with 0.184. 展开更多
关键词 COWPEA Seed PROTEIN content PROTEIN Measurement method Rapid N ANALYZER Near-Infrared Reflectance (NIR) Vigna unguiculata
下载PDF
Chemical Analysis Method for Carbon Bearing Refractory Products——Determination of Magnesium Oxide Content by CyDTA Volumetric Method
11
作者 Zhang Xiaohui 《China's Refractories》 CAS 2007年第1期37-38,共2页
This standard specifies the method summary, reagents, apparatus, sampling, procedure, test results calculation and permissible tolerance of the determination of magnesium oxide by CyDTA volumetric method.
关键词 Determination of Magnesium Oxide content by CyDTA Volumetric method TEST Chemical Analysis method for Carbon Bearing Refractory Products
下载PDF
Effects of Different Preservation Methods on Vitamin C and Nitrate Content in Vegetables 被引量:1
12
作者 Lili SONG Huijuan ZHANG 《Asian Agricultural Research》 2019年第4期62-66,共5页
This paper studied and compared the effects of three preservation methods( normal temperature 20℃,fresh-keeping box cold storage 4℃,and fresh-keeping box + fresh-keeping film cold storage 4℃) on six kinds of vegeta... This paper studied and compared the effects of three preservation methods( normal temperature 20℃,fresh-keeping box cold storage 4℃,and fresh-keeping box + fresh-keeping film cold storage 4℃) on six kinds of vegetables. The results showed that the content of vitamin C in the six vegetables was higher in cold storage than in normal temperature storage; the nitrate content was lower in cold storage than in normal temperature storage. In both the normal temperature storage and cold storage,the vitamin C in vegetables declined with the increase of the storage time,while the nitrate content increased with the increase of the storage time. Thus,cold storage has better fresh-keeping effect for vegetables. In cold storage conditions,the vitamin C content was higher in vegetables packaged by fresh-keeping box,and the nitrate content was lower,followed by the fresh-keeping film + fresh-keeping box cold storage. In conclusion,the best preservation method for vegetable is fresh-keeping box cold storage. 展开更多
关键词 PRESERVATION methods VEGETABLE VC content NITRATE content Ultraviolet SPECTROPHOTOMETRY
下载PDF
壳源氦气成藏主控因素及资源评价方法研究 被引量:1
13
作者 吴义平 王青 +6 位作者 陶士振 王建君 李谦 张宁宁 吴晓智 李浩武 王晓波 《地学前缘》 EI CAS CSCD 北大核心 2024年第1期340-350,共11页
当前国内外尚无系统的氦气资源评价方法以及针对性的参数取值标准。通过天然气和氦气的成藏要素对比,明确了载体气和壳源氦气的异源同储、同源同储和同源异储3类共生关系,以及壳源氦气成藏的8个关键因素。构建了4类10种氦气资源分级分... 当前国内外尚无系统的氦气资源评价方法以及针对性的参数取值标准。通过天然气和氦气的成藏要素对比,明确了载体气和壳源氦气的异源同储、同源同储和同源异储3类共生关系,以及壳源氦气成藏的8个关键因素。构建了4类10种氦气资源分级分类评价方法,其中含量法包括5个亚类,统计法包括1个亚类,类比法包括3个亚类,成因法1个亚类,初步解决了氦气资源定量计算的难题。结果表明:高氦气含量的气藏一般为常压及低压气藏,氦气含量与氦源岩类型、铀钍含量和氦源岩规模3个参数呈正向关系,而与离主断裂距离、埋深和生烃强度3个参数呈负相关,适度的基底构造活动有利于氦气释放及富集。基于8类氦气成藏主控因素与氦气含量的定量关系,建立了氦气含量类比法。基于异源同储不同序的原理,构建了氦气资源规模序列法;基于放射性元素衰变释氦机理,建立了氦气成因法。氦气资源评价方法在国内外得到了较为广泛的应用,研究成果将为我国氦气储量规模发现提供了有效支撑。 展开更多
关键词 载体气 共生关系 氦气含量 生氦法 规模序列 资源评价
下载PDF
Chemical Analysis of Magnesia and Magnesia-Alumina Refractory Materials——Flame atomic absorption spectrometric method for determination of calcium oxide content
14
作者 ZHANG Xiaohui 《China's Refractories》 CAS 2006年第4期41-43,共3页
1 Scope This standard specifics the determination of calcium oxide coutent by flame atomic absorption spectrometric method.
关键词 Chemical Analysis of Magnesia and Magnesia-Alumina Refractory Materials Flame atomic absorption spectrometric method for determination of calcium oxide content
下载PDF
Study on Colorimetric Method and Content Determination of Total Phenol in Homemade Plum Wine 被引量:2
15
作者 Yun TENG Pei QUN +1 位作者 Xue ZHAI Yuan LIU 《Medicinal Plant》 2017年第1期22-26,共5页
[Objectives] To study on colorimetric method and content determination of total phenol in homemade plum wine. [Methods]The optimal determination condition of total polyphenols content in plum wine( commercially availa... [Objectives] To study on colorimetric method and content determination of total phenol in homemade plum wine. [Methods]The optimal determination condition of total polyphenols content in plum wine( commercially available and homemade) by Folin-Ciocalteu method was inspected,and commercially available and homemade plum wine was evaluated by the method. [Results]The optimal determination conditions of total polyphenols content: sample dose of 1. 0 m L,Folin-Ciocalteu reagent of 1 m L,4% Na_2CO_3 solution of 4. 0 m L,reaction temperature of 50 ℃,reaction time of 1. 5 h,and determination wavelength of 756 nm. Absorbance showed good linear relationship with total polyphenols content within the range of 17. 73-59. 12 μg/m L( y = 14. 878 x + 0. 0739,R^2= 0. 9998). Recovery rate of adding standard sample was between 98. 8% and 103. 5%,and relative standard deviation was 2. 0%( n = 5). [Conclusions]The method had high precision degree and good stability,which was suitable for measuring total polyphenols content in plum wine( commercially available and homemade). 展开更多
关键词 PLUM wine(commercially available and homemade) FOLIN-CIOCALTEU SPECTROPHOTOMETRIC method TOTAL POLYPHENOLS content determination
下载PDF
A TOTAL CONTENT X—RAY FLUORESCENCE METHOD FOR COPPER PROSPECTING
16
作者 周四春 谢庭周 葛良全 《Nuclear Science and Techniques》 SCIE CAS CSCD 1992年第3期191-195,共5页
A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of... A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of a Cu deposit. Applications of the technique in Northeast China are presented. 展开更多
关键词 Portable X-RAY FLUORESCENCE ANALYZERS Total content X-RAY FLUORESCENCE method PROSPECTING for COPPER DEPOSITS
下载PDF
THE QUICK DETERMINATION METHOD OF RESIN CONTENT IN LARCH WOOD
17
作者 Lu Wenda Xu Xiuwen Zhao Dejun Tan Haiyan Northeast Forestry University 《Journal of Northeast Forestry University》 SCIE CAS CSCD 1992年第1期62-67,共6页
The resin content in larch wood is usually determined by the traditionalBenzene-Alcohol Extract Method(BAEM).In order to meet the requirement of production prac-tice,the authors present two simple quick determination ... The resin content in larch wood is usually determined by the traditionalBenzene-Alcohol Extract Method(BAEM).In order to meet the requirement of production prac-tice,the authors present two simple quick determination methods,IR lamp method and hydrogenperoxide solution method.Compared with the results of traditional method,the results of newmethods are nearly the same as former,therefore,both two methods can reflect the change condi-tion of resin content in wood. 展开更多
关键词 LARCH Resin content Benzene-Alcohol EXTRACT method (BAEM) IR lamp method (IRLM) Hydrogen PEROXIDE solution method (HPSM)
下载PDF
Method of Predicting Water Content in Crude Oil Based on Measuring Range Automatic Switching
18
作者 陈祥光 朱文博 +1 位作者 赵军 任磊 《Journal of Beijing Institute of Technology》 EI CAS 2010年第1期87-91,共5页
Water content in output crude oil is hard to measure precisely because of wide range of dielectric coefficient of crude oil caused by injected dehydrating and demulsifying agents.The method to reduce measurement error... Water content in output crude oil is hard to measure precisely because of wide range of dielectric coefficient of crude oil caused by injected dehydrating and demulsifying agents.The method to reduce measurement error of water content in crude oil proposed in this paper is based on switching measuring ranges of on-line water content analyzer automatically.Measuring precision on data collected from oil field and analyzed by in-field operators can be impressively improved by using back propogation (BP) neural network to predict water content in output crude oil.Application results show that the difficulty in accurately measuring water-oil content ratio can be solved effectively through this combination of on-line measuring range automatic switching and real time prediction,as this method has been tested repeatedly on-site in oil fields with satisfactory prediction results. 展开更多
关键词 water content in crude oil prediction method BP network measuring range automatic switching
下载PDF
城市生态学长期监测的几个关键问题
19
作者 王效科 任玉芬 +4 位作者 张红星 孙旭 苏芝敏 李铣 欧阳志云 《生态学报》 CAS CSCD 北大核心 2024年第14期5945-5959,共15页
伴随城市人口快速聚集及人类活动加剧,城市生态环境质量及其对人类社会经济发展的支撑能力正在受到严重挑战,城市生态系统及其变化的研究越来越受到重视,国内外涌现出大量城市生态学长期监测工作,但相关监测方法的讨论还很少。在分析城... 伴随城市人口快速聚集及人类活动加剧,城市生态环境质量及其对人类社会经济发展的支撑能力正在受到严重挑战,城市生态系统及其变化的研究越来越受到重视,国内外涌现出大量城市生态学长期监测工作,但相关监测方法的讨论还很少。在分析城市生态学长期监测类型和实践经验基础上,从城市面临的环境胁迫和建设管理需求出发,构建了城市生态学长期监测的“胁迫+需求-生态系统响应”总体思路框架;从科学上最基本和社会上最关心的城市生态系统要素、格局和过程着眼,提出城市生态学长期监测的7项内容(土地覆盖与利用、人居环境质量、生物多样性、生物质生产、水文过程、生物地球化学循环和物质代谢);并分析了城市生态学长期监测的4种方法(遥感监测、仪器监测、调查监测、公众科学监测),分析了城市生态学长期监测单元及其空间布局及监测频率。这将为我国城市生态学长期监测工作开展提供方法论基础和实践参考。 展开更多
关键词 城市生态学 长期监测 监测内容 监测方法 监测频率
下载PDF
我国安宁疗护通识创新教育思考
20
作者 祁晓娜 姚强 +4 位作者 于钦明 赵苗苗 王妍 钟梦岚 于立娟 《中国医学伦理学》 北大核心 2024年第3期332-338,共7页
随着中国人口老龄化进程加剧,安宁疗护作为提高临终患者生命质量的重要保障越来越受到社会关注,需求不断增加。安宁疗护需要复合型人才,通识教育可提升人们对安宁疗护的认知和理解,使更多的人了解、接纳并参与安宁疗护。随着安宁疗护知... 随着中国人口老龄化进程加剧,安宁疗护作为提高临终患者生命质量的重要保障越来越受到社会关注,需求不断增加。安宁疗护需要复合型人才,通识教育可提升人们对安宁疗护的认知和理解,使更多的人了解、接纳并参与安宁疗护。随着安宁疗护知识和技术的进步,传统的灌输式教育模式已无法满足实际需求,因此,急需创新安宁疗护教育策略。通过分析目前中国安宁疗护通识教育存在的问题,并从建立安宁疗护通识创新教育体系和评价体系、多元化的教育内容和方法、加强医务人员培训、促进学员群体多元化、加强社会公众安宁疗护知识普及等方面提出安宁疗护通识创新教育的思考和建议。 展开更多
关键词 安宁疗护 通识教育 创新教育 教育内容 教育方式
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部