期刊文献+
共找到271篇文章
< 1 2 14 >
每页显示 20 50 100
新课程理念下,贫困山区《蒸发》探究设计
1
作者 潘中举 《物理教学探讨(中学教学教研版)》 2005年第10期31-31,34,共2页
关键词 《蒸发》 新课程理念 贫困山区 设计 教材分析 《物理》 北师大版 第四节 八年级
下载PDF
玩物悟理——《蒸发》实验教学设计
2
作者 陈家军 《中小学实验与装备》 2013年第1期51-51,共1页
新课程要求培养学生的创新精神和实践能力,要求教师用教材教,而不是教教材。人教版八年级物理上册第四章第三节《汽化和液化》中关于蒸发的教学内容,书中只有6句话与1幅图片,却包含了蒸发的定义、发生条件、发生部位、影响因素、蒸... 新课程要求培养学生的创新精神和实践能力,要求教师用教材教,而不是教教材。人教版八年级物理上册第四章第三节《汽化和液化》中关于蒸发的教学内容,书中只有6句话与1幅图片,却包含了蒸发的定义、发生条件、发生部位、影响因素、蒸发吸热、蒸发与沸腾的关系等内容。在这一部分的教学中,笔者进行了认真的挖掘,把这部分内容设计成探究实验,让学生回归生活,在玩物中悟理。 展开更多
关键词 实验教学设计 《蒸发》 实践能力 创新精神 课程要求 教学内容 发生条件 探究实验
下载PDF
构建有效教学从“三读懂”做起——以《蒸发》教学为例 被引量:1
3
作者 谢杰妹 《中学物理教学参考》 北大核心 2013年第9期5-8,共4页
有效性是教学的永恒追求,每一轮教学改革都是为了更好提高教学质量,更好促进学生发展.教学的载体是教材,教学的对象是学生,教学的主阵地在课堂,构建有效教学应从读懂教材、学生和课堂做起.笔者以《蒸发》课堂教学为例,从教材、... 有效性是教学的永恒追求,每一轮教学改革都是为了更好提高教学质量,更好促进学生发展.教学的载体是教材,教学的对象是学生,教学的主阵地在课堂,构建有效教学应从读懂教材、学生和课堂做起.笔者以《蒸发》课堂教学为例,从教材、学生和课堂三方面,谈谈自己对构建有效教学的一点认识. 展开更多
关键词 有效教学 《蒸发》 学生发展 课堂教学 教学质量 教学改革 有效性 教材
原文传递
《蒸发》一课的教学设计
4
作者 李杰 《小学教学设计(文科版)》 2002年第12期31-31,41,共2页
关键词 《蒸发》 教学设计 小学 自然教学
原文传递
OUTBREAK蒸发密令
5
《家用电脑与游戏》 2002年第4期58-58,共1页
关键词 电脑游戏 《蒸发密令》 游戏软件
下载PDF
Primary Comments on Chemotaxonomy of Paris spp. Based on Saponins Analysis 被引量:6
6
作者 黄芸 王强 崔力剑 《Journal of Chinese Pharmaceutical Sciences》 CAS 2005年第3期176-180,共5页
Aim The several species of the genus Paris called "Chonglou" are famous traditional Chinese herbal medicines. We established the quantitative analysis method of the steroidal saponins in some species of the genus Pa... Aim The several species of the genus Paris called "Chonglou" are famous traditional Chinese herbal medicines. We established the quantitative analysis method of the steroidal saponins in some species of the genus Paris and discussed their relations. Methods We detected the contents of 11 steroidal saponins in Paris samples with a Kromasel C18 ( 150 mm× 4.6 mm ID, 5μm) column which was subjected to gradient elution with acetonitrile-water (30:70- 60:40, V/V) at a flow rate of 1 mL· min^-1 by HPLC-ELSD and established chemical cluster tree using SPSS 11 software. Results All the samples could be separated and calibration curves of 11 saponins were prepared. We successfully detected the contents of 11 steroidal saponins in 14 Paris spp. in 30 min. The recovery for the assay of saponins was between 95 % and 97 %. The RSD of precision of 11 saponins and stability of samples were below 3 %. Chemical phylogenetic tree based on saponin contents indicated that 17 samples of Paris spp. clustered separately. Conclusion The established method is accurate and convenient, and suitable for the quantitative analysis of these 11 steroidal saponins in Paris spp.. The chemical phylogenetic tree is in accordance with Takhtajian classical taxonomy. 展开更多
关键词 PARIS steroidal saponin cluster analysis HPLC-ELSD
下载PDF
Fretting wear behavior of Inconel 690 in hydrazine environments 被引量:2
7
作者 张晓宇 任平弟 +1 位作者 彭金方 朱旻昊 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第2期360-367,共8页
The friction and wear behaviors of Inconel 690 flat against Si3Ni4 ball were investigated using a hydraulic fretting test rig equipped with a liquid container device. The loads of 20-80 N, reciprocating amplitudes of ... The friction and wear behaviors of Inconel 690 flat against Si3Ni4 ball were investigated using a hydraulic fretting test rig equipped with a liquid container device. The loads of 20-80 N, reciprocating amplitudes of 80-200 μm and two different environments (distilled water and hydrazine solution at temperatures from 25 to 90 ℃) were selected. The results show that the ratio of Ft/Fn is lower in distilled water than that in hydrazine solution at the same temperature in the slip regime. Both the ratio of Ft/Fn and wear volume gradually increase with increasing medium temperature under the given normal load and displacement amplitude. Besides the displacement amplitude and load, temperature also plays an important role for wear behavior of Inconel 690 material. The increase of temperature could reduce the concentration of dissolved oxygen, and promote the absorption reaction of hydrazine and dissolved oxygen. As a result, the oxidative corrosion rate is obviously lowered. Abrasive wear and delamination wear are the main mechanisms of Inconel 690 in distilled water. However, in hydrazine solution the cracks accompanied by abrasive wear and delamination wear are the main mechanisms. 展开更多
关键词 fretting wear steam generator delamination wear
下载PDF
Research on Climate Type Distribution in Yunnan Golden Corridor Tobacco Area 被引量:1
8
作者 马俊红 李军营 +2 位作者 马二登 逄涛 卢秀萍 《Agricultural Science & Technology》 CAS 2013年第12期1742-1746,共5页
In order to further evaluate the effect of climate conditions of Yunnan Golden Corridor on tobacco production, meteorological factors data such as sun- shine, temperature and rainfall over 34 years (1971-2004) in 53... In order to further evaluate the effect of climate conditions of Yunnan Golden Corridor on tobacco production, meteorological factors data such as sun- shine, temperature and rainfall over 34 years (1971-2004) in 53 counties of 10 pre- fectures across Yunnan Golden Corridor were analyzed. Based on the SPSS sys- tematic clustering method, with the growth stage average temperature, highest tem- perature, lowest temperature, total sunshine duration, rainfall, evaporation and aver- age relative humidity being the indexes, Yunnan Golden Corridor Tobacco Area could be divided into places with four climate types. The characteristics of four cli- mate types were also analyzed, which indicates that the differences of growth stage average temperature, highest temperature, total sunshine duration, and average rela- tive humidity among four climate types were relatively small, while there existed sig- nificant differences between growth stage lowest temperature, rainfall and evapora- tion of four climate types, which might be the key factors that influence the special quality of tobacco from Golden Corridor. 展开更多
关键词 Climate RAINFALL EVAPORATION
下载PDF
Influence Factors on Particle Growth for On-line Aerosol Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry 被引量:1
9
作者 夏玮玮 提汝芳 +2 位作者 张子良 郑海洋 方黎 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第3期269-273,I0001,共6页
An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometer for on-line bioaerosol detection and characterization,... An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the con- denser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of bi- ological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols. 展开更多
关键词 Matrix-assisted laser desorption/ionization Particle growth Homogeneous condensation Evaporation/condensation flow cell
下载PDF
Design calculation of porous ceramics tube type dew point indirect evaporative cooler 被引量:1
10
作者 毛秀明 黄翔 文力 《Journal of Southeast University(English Edition)》 EI CAS 2010年第2期205-208,共4页
To improve the wall surface hydrophilicity of a tube type indirect evaporative cooler,a new method adopting porous ceramics is proposed.This method realizes the combination of porous ceramics and the evaporative cooli... To improve the wall surface hydrophilicity of a tube type indirect evaporative cooler,a new method adopting porous ceramics is proposed.This method realizes the combination of porous ceramics and the evaporative cooling technique.The design calculation of the porous ceramics tube type dew point indirect evaporative cooler are carried out from such aspects as the volumes and status parameters of the primary and secondary air,the cooler structure,the heat transfer of the solid porous ceramic tubes and the resistance of the cooler.The calculation results show that the design is reasonable.Finally,based on the design calculation,the porous ceramics tube type dew point indirect evaporative cooler is successfully manufactured. 展开更多
关键词 tube type indirect evaporative cooler dew point porous ceramics design calculation
下载PDF
Liquid dehumidification-assisted evaporative supercooling method for ice slurry production 被引量:1
11
作者 李秀伟 张小松 《Journal of Southeast University(English Edition)》 EI CAS 2010年第2期351-354,共4页
Due to the fact that the conventional ice slurry production system using supercooled water suffers from ice block and depends heavily on electric power,a novel ice slurry production system is proposed.The new system c... Due to the fact that the conventional ice slurry production system using supercooled water suffers from ice block and depends heavily on electric power,a novel ice slurry production system is proposed.The new system consists of two major parts:the evaporative supercooling process and the liquid dehumidification process.The classical diffusion-control equation is improved by introducing an impact factor into the simulation analysis in the evaporative supercooling process.Meanwhile,experiments are carried out by adopting the particle analyzer to detect the radii and the velocities of the droplets,and an infrared camera to examine the temperature profile of the physical process.It is found that the theoretical conclusion agrees well with the experimental results.Compared with the conventional system,the new system can alleviate the burden on electric power and raise efficiency.These improvements are essentially attributed to the reutilization of the inner waste heat generated from the system itself. 展开更多
关键词 ice slurry liquid dehumidification EVAPORATION
下载PDF
Effects of Different Thicknesses of Gravel Covering on Daily Soil Evaporation 被引量:1
12
作者 周约 谢铁娜 《Agricultural Science & Technology》 CAS 2015年第10期2347-2349,2353,共4页
[Objective] The research aimed to explore the most suitable gravel cover- ing thickness for selenium sand melon in arid region of central Ningxia. [Method] The natural gravel, which was from Nanshantai Region in Zhong... [Objective] The research aimed to explore the most suitable gravel cover- ing thickness for selenium sand melon in arid region of central Ningxia. [Method] The natural gravel, which was from Nanshantai Region in Zhongwei City, Ningxia, was acted as test materials to study the effects of different thicknesses of gravel covering on daily evaporation using evaporator overall weighing method. [Result] The daily evaporation capacity order of the gravel covering thickness was as follows: CK〉HI(5 cm)〉 H2(8 cm)〉 H3(10 cm)〉 H4(15 cm). Meanwhile, with the increase of test days, the difference of cumulative evaporation capacity between H3 (10 cm) and H4 (15 cm) decreased gradually. Soil evaporation capacity reduced at the pow- er function with the increase of gravel covering thickness, and the decision coeffi- cient of the fitted curve reached to 0.925 5. [Conclusion] With the increase of gravel covering thickness, evaporation capacity of soil reduced gradually, and the soil water content increased gradually. Gravel covering could effectively reduce the evapora- tion. The thicker of covering, the more obvious inhibition effect on evaporation. The thickness of covering should increase moderately to prevent moisture loss from e- vaporation. Gravel inhibition effect on the evaporation wasn't obvious when the gravel covering thickness reached more than 10 cm. 10 cm gravel covering was the most appropriate thickness for local natural condition. The soil evaporation capacity along with the change of gravel covering could be simulated with power function e- quation Y=at^b. 展开更多
关键词 Thickness Gravel covering Soil evaporation
下载PDF
Experimental Study on the Utilization of Shallow Groundwater for Spring Wheat 被引量:1
13
作者 王炳亮 《Agricultural Science & Technology》 CAS 2011年第1期108-112,132,共6页
[Objective]The paper aimed to study effect of shallow groundwater at different depths on crop water requirement and crop evaporation in spring wheat field.[Method]Five treatments of shallow groundwater table at differ... [Objective]The paper aimed to study effect of shallow groundwater at different depths on crop water requirement and crop evaporation in spring wheat field.[Method]Five treatments of shallow groundwater table at different depth were designed to do evaporation experiment for spring wheat in 2008-2009.[Result]The groundwater at different depths had great impact on crop growth and field evaporation;its supply accounted for 0-52% of actual evapotranspiration.Atmospheric evaporation and crop rooting depth were the major factors to affect the uptake of groundwater at shallow table,and the supply of deep groundwater was controlled by groundwater table.[Conclusion]The study reveled the pattern of evapotranspiration of spring wheat and evaporation of shallow groundwater at different depth,in order to supply basis for the rational and effective utilization of shallow groundwater as well as optimization of the irrigation scheduling for spring wheat. 展开更多
关键词 Groundwater table Spring wheat Groundwater evaporation Utilization of groundwater
下载PDF
APPLICATION POSSIBILITY OF BINARY NONAZEOTROPIC REFRIGERANT IN JET REFRIGERATION *
14
作者 张于峰 张利民 +1 位作者 李灿华 孙萍 《Transactions of Tianjin University》 EI CAS 1998年第1期26-30,共5页
This paper analyzes the possibility of applying binary nonazeotropic refrigerants in the jet refrigeration cycle. The thermodynamic cycle performance of two kinds of working pairs (R30/R142b, R30/R124) are calculated ... This paper analyzes the possibility of applying binary nonazeotropic refrigerants in the jet refrigeration cycle. The thermodynamic cycle performance of two kinds of working pairs (R30/R142b, R30/R124) are calculated using the EOS of PR equation of state, and the results are discussed. The theoretical calculations indicate that refrigerating quality can be improved if the binary mixtures evaporate just in the low temperature region. The character of the rejecter to compress two phase medium supports the possibility of this kind of cycle. 展开更多
关键词 jet refrigeration evaporating in low temperature region vapour liquid two phase compression binary nonazeotropic refrigerant
下载PDF
Interaction of Soybean Phospholipids Based Lipo-Vesicle and Surfactants of Bile Salts In Vitro
15
作者 李凤前 胡晋红 朱全刚 《Journal of Chinese Pharmaceutical Sciences》 CAS 2001年第3期136-139,共4页
Liposomes were prepared with natural soybean phospholipids by extrusion method after rotating-film evaporating technique. Transmission electron micrography was used to detect the appearances of the prepared liposomes,... Liposomes were prepared with natural soybean phospholipids by extrusion method after rotating-film evaporating technique. Transmission electron micrography was used to detect the appearances of the prepared liposomes, and the liposome diameter was also measured. The prepared liposomes were sphere in shape with the mean diameter of 217 nm and span of 0.838. The phospholipid bilayer structure, suitable for entrapping various effector molecules, could be seen clearly under transmission electron microscopy. The bile salts of sodium cholate and sodium deoxycholate were used as the surfactants to investigate their interaction with liposomes. The turbidities for the mixture of bile salts and liposomes were evaluated by the visible spectrometry method at the wavelength of 500 nm. And the diameter changes of liposomes were also tested to examine the effect of bile salts on liposomes. At the beginning, the diameters and turbidities of liposomes increased a little as the result of mixed micelles formation during the different stages for the structure changes of surfactant-liposomes micelles. The further added bile salts decreased the diameters and turbidities of liposomes. The liposome suspension underwent several rearrangements before small mixed micelles formed. And the diameter of liposomes changed regularly. The interaction of bile salts and liposomes is important for the further study of the behaviors of liposomes in vivo. The drug loaded and release properties of liposomes can also be well reflected by the interaction of liposomes and surfactants. 展开更多
关键词 Soybean phospholipids Liposomes Bile salt Interaction in vitro DIAMETER TURBIDITY
下载PDF
Study on Artificial Neural Network Model for Crop Evapotranspiration
16
作者 冯雪 潘英华 张振华 《Agricultural Science & Technology》 CAS 2007年第3期11-14,41,共5页
Based on potted plant experiment, BP-artifieial neural network was used to simulate crop evapotranspiration and 3 kinds of artificial neural network models were constructed as ET1 (meteorological factors), ET2( met... Based on potted plant experiment, BP-artifieial neural network was used to simulate crop evapotranspiration and 3 kinds of artificial neural network models were constructed as ET1 (meteorological factors), ET2( meteorological factors and sowing days) and ET3 (meteorological factors, sowing days and water content). And the predicted result was compared with actual value ET that was obtained by weighing method. The results showed that the ET3 model had higher calculation precision and an optimum BP-artificial neural network model for calculating crop evapotranspiration. 展开更多
关键词 Crop evapotranspiration BP-artificial neural network Fitting precision
下载PDF
Determination of Astragaloside IV in Yupingfeng Oral Solution by HPLC-ELSD Method
17
作者 王建舫 张倩 穆祥 《Agricultural Science & Technology》 CAS 2015年第2期197-199,共3页
[Objective] This study aimed to establish a method for determining the content of Astragaloside IV in Yupingfeng oral solution.[Method] The HPLC-ELSD method was adopted.The chromatographic column was Venusil MP(4.6 m... [Objective] This study aimed to establish a method for determining the content of Astragaloside IV in Yupingfeng oral solution.[Method] The HPLC-ELSD method was adopted.The chromatographic column was Venusil MP(4.6 mm × 150 mm,5 μm).The mobile phase was acetonitrile-water(35∶65).The ELSD evaporator tube temperature was 65 ℃.N2 was used as the carrier gas(pressure,30 psi).[Result] When the content of Astragaloside IV ranged from 0.5 to 5.0 μg,the Astragaloside IV content showed a good linear relationship with peak area(r=0.999,n=6).The average recovery was 96.36%,and the RSD was 2.46%.[Conclusion] This method is accurate and reliable,and can be applied in the quality control of Yupingfeng oral solution. 展开更多
关键词 HPLC ELSD Yupingfeng oral solution Astragaloside IV
下载PDF
Modelling and Solution of a Ablation-Transpiration Cooling Control Systems
18
作者 郭宝珠 郝涌 《Journal of Beijing Institute of Technology》 EI CAS 1994年第2期114-121,共8页
A controlled model of thermal shield of ablation with trapspiration cooling is develoed. The existence and uniqueness of the classical solution can be obtained by Friedman and Jiang's methods. The positivity of th... A controlled model of thermal shield of ablation with trapspiration cooling is develoed. The existence and uniqueness of the classical solution can be obtained by Friedman and Jiang's methods. The positivity of the solution is proved and the conditions for the coolant flux under which the abladtion process will complete in finite time are also determined. Finally, we show the existence of critical coolant flux beyond which the ablation material begin melting. 展开更多
关键词 ablation evaporative cooling dristributed parameter system the boundary
下载PDF
Morphology and Growth Process of Bat-like ZnO Crystals by Thermal Evaporation 被引量:1
19
作者 高品 王凯 +2 位作者 黄超 孟路 徐法强 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2016年第3期369-373,I0002,共6页
A novel bat-like ZnO nanostructure was synthesized on the silicon substrate by simple ther- mal evaporation of zinc powders without any catalyst. Each bat-like nanorod ("nanobat") is composed of a hexagonal head, ... A novel bat-like ZnO nanostructure was synthesized on the silicon substrate by simple ther- mal evaporation of zinc powders without any catalyst. Each bat-like nanorod ("nanobat") is composed of a hexagonal head, a continuous neck and a thin handle. High-resolution transmission electron microscopy and selected area electron diffraction results reveal the single-crystalline feature and the growing direction along [0001] of the nanobat. The vapor- solid mechanism was found suitable to explain the growth process of the nanobat and a schematic model was proposed in detail based on the experimental results. 展开更多
关键词 ZNO Thermal evaporation NANOSTRUCTURE Growth process
下载PDF
Evapotranspiration and Soil Moisture Balance for Vegetative Restoration in a Gully Catchment on the Loess Plateau, China 被引量:15
20
作者 HUANG Yi-Long CHEN Li-Ding +2 位作者 FU Bo-Jie ZHANG Li-Ping WANG Yan-Lin 《Pedosphere》 SCIE CAS CSCD 2005年第4期509-517,共9页
Evapotranspiration, soil moisture balance and the dynamics in a gully catchment of the Loess Plateau in China were determined with 6 land use treatments including natural grassland, shrubs (Caragana rnicrophylla), t... Evapotranspiration, soil moisture balance and the dynamics in a gully catchment of the Loess Plateau in China were determined with 6 land use treatments including natural grassland, shrubs (Caragana rnicrophylla), two woodlands (Prunus armeniaca var. ansu and Pinus tabulaeformis), cultivated fallow, and farmland (Triticum aestiuum L.) in order to obtain a better understanding of soil moisture balance principles and to improve vegetation restoration efficiency for ecological rebuilding on the plateau. Average runoff from cultivated fallow was very high, reaching 10.3% of the seasonal rainfall. Evapotranspiration under T. aestivurn was not significantly different from natural grasslands. Compared with natural grass, evapotranspiration was significantly greater (P 〈 0.05) in 2002 and there was an increase in soil moisture depleted in the 1-3 m soil under P. armeniaca, P. tabulaeformis and C. microphylla. During the two years of the study the average soil moisture (0-100 cm soil profile) of T. aestivurn was generally the highest, with P. armeniaca, P. tabulaeformis and C. rnicrophylla usually the lowest. Thus, according to the soil moisture balance principle for this area the planned reforestation project was not ecologically reasonable. Reducing human disturbance and restoration with grass could be more effective. 展开更多
关键词 ecological restoration EVAPOTRANSPIRATION GULLY Loess Plateau soil moisture balance
下载PDF
上一页 1 2 14 下一页 到第
使用帮助 返回顶部