首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   176篇
  免费   14篇
  国内免费   2篇
电工技术   5篇
化学工业   28篇
金属工艺   5篇
机械仪表   3篇
建筑科学   10篇
能源动力   10篇
轻工业   20篇
水利工程   4篇
石油天然气   8篇
无线电   14篇
一般工业技术   45篇
冶金工业   4篇
自动化技术   36篇
  2023年   3篇
  2022年   9篇
  2021年   11篇
  2020年   7篇
  2019年   10篇
  2018年   11篇
  2017年   15篇
  2016年   16篇
  2015年   12篇
  2014年   15篇
  2013年   25篇
  2012年   15篇
  2011年   11篇
  2010年   11篇
  2009年   9篇
  2008年   4篇
  2007年   2篇
  2006年   1篇
  2005年   2篇
  1998年   2篇
  1997年   1篇
排序方式: 共有192条查询结果,搜索用时 0 毫秒
31.
Sonodisruption behavior of re-assembled casein micelles was compared at two ultrasound frequencies (35 and 130 kHz) by turbidity measurement and laser-diffraction based particle size analysis. Sonochemical ultrasound (130 kHz) was more effective than power ultrasound (35 kHz) in micelle disruption. This was attributed to the higher strain rates generated upon implosion of cavities, as well as the liberation of more free radicals to the surrounding medium. The higher the pH of solution, the more effective was the ultrasonic disruption due to a looser expanded assembly of particles at higher pH values. Sonochemical ultrasound decreased the consistency coefficient of casein solutions and increased their flow index except at a pH value of 6.35, while power ultrasound did not affect the flow behavior of solutions across the whole pH range.  相似文献   
32.
The effect of heat-treatment on foaming properties of ostrich albumen was investigated. At pH 7.5, coagulation of ovotransferrin (OT) resulted in minimum foaming capacity (FC) and maximum foam density (FD). While both exposure of sulfhydryl groups of ovalbumin (OV) and OT-OV interactions improved FC at lower pH, neither of them had beneficial effect on FC at pH 9. At pH 9, FC and FD were mildly affected by heat-treatment because of less aggregation of OT, then FC decreased due to covalent aggregates composed of ovomucin and OV, but at higher temperatures, higher level of OV unfolding resulted in enhanced FC.  相似文献   
33.
The phytochemicals content and radical scavenging activity of pistachio (Pistacia vera L.) hull extract obtained by different solvents (water, ethanol, and butanol) were measured and compared. Water was selected as superior solvent. Ultrasound-assisted aqueous extraction of the hull by power ultrasound (35 kHz) was more efficient in ascending the phytochemicals content than the sonochemical ultrasonication (130 kHz). High-performance liquid chromatography-mass spectrometry showed increased amounts of vanillic acid, p-coumaric acid, naringenin, and catechin in ultrasound-assisted extracts. Post-extraction sonication declined significantly the phenolics amount and antioxidant property of the aqueous extract. Microwave-assisted extraction increased the phenolics and flavonoids content at extract in a power-dependent trend.  相似文献   
34.
The effects of spray‐drying air temperature, aspirator rate (drying air mass flow rate), peristaltic pump rate (feed mass flow rate) and spraying air mass flow rate on microencapsulation properties of fish oil including moisture content, particle size, bulk density, encapsulation efficiency and peroxide were investigated. The process was carried out on a mini spray dryer, and skim milk powder was used as the encapsulating wall material. Results indicated that increasing inlet air temperature increased the particle size, encapsulation efficiency and peroxide value but decreased the bulk density and moisture content of product. Increasing aspirator rate resulted in increased particle size and peroxide value but decreased the moisture content and bulk density. Increase in feed mass flow rate increased the moisture content, particle size, bulk density and peroxide value but decreased the encapsulation efficiency of microcapsules. The encapsulation efficiency and bulk density increased with the increasing aspirator rate but moisture content, particle size and peroxide value decreased.  相似文献   
35.
36.
37.
The charge, discharge, and total energy efficiencies of lithium‐ion batteries (LIBs) are formulated based on the irreversible heat generated in LIBs, and the basics of the energy efficiency map of these batteries are established. This map consists of several constant energy efficiency curves in a graph, where the x‐axis is the battery capacity and the y‐axis is the battery charge/discharge rate (C‐rate). In order to introduce the energy efficiency map, the efficiency maps of typical LIB families with graphite/LiCoO2, graphite/LiFePO4, and graphite/LiMn2O4 anode/cathode are generated and illustrated in this paper. The methods of usage and applications of the developed efficiency map are also described. To show the application of the efficiency map, the effects of fast charging, nominal capacity, and chemistry of typical LIB families on their energy efficiency are studied using the generated maps. It is shown how energy saving can be achieved via energy efficiency maps. Overall, the energy efficiency map is introduced as a useful tool for engineers and researchers to choose LIBs with higher energy efficiency for any targeted applications. The developed map can be also used by energy systems designers to obtain accurate efficiency of LIBs when they incorporate these batteries into their energy systems.  相似文献   
38.
Miniaturized laboratories on chip platforms play an important role in handling life sciences studies. The platforms may contain static or dynamic biological cells. Examples are a fixed medium of an organ‐on‐a‐chip and individual cells moving in a microfluidic channel, respectively. Due to feasibility of control or investigation and ethical implications of live targets, both static and dynamic cell‐on‐chip platforms promise various applications in biology. To extract necessary information from the experiments, the demand for direct monitoring is rapidly increasing. Among different microscopy methods, optical imaging is a straightforward choice. Considering light interaction with biological agents, imaging signals may be generated as a result of scattering or emission effects from a sample. Thus, optical imaging techniques could be categorized into scattering‐based and emission‐based techniques. In this review, various optical imaging approaches used in monitoring static and dynamic platforms are introduced along with their optical systems, advantages, challenges, and applications. This review may help biologists to find a suitable imaging technique for different cell‐on‐chip studies and might also be useful for the people who are going to develop optical imaging systems in life sciences studies.  相似文献   
39.
Objective: To optimize air-jet milling conditions of ibuprofen (IBU) using design of experiment (DoE) method, and to test the generalizability of the optimized conditions for the processing of another non-steroidal anti-inflammatory drug (NSAID).

Methods: Bulk IBU was micronized using an Aljet mill according to a circumscribed central composite (CCC) design with grinding and pushing nozzle pressures (GrindP, PushP) varying from 20 to 110?psi. Output variables included yield and particle diameters at the 50th and 90th percentile (D50, D90). Following data analysis, the optimized conditions were identified and tested to produce IBU particles with a minimum size and an acceptable yield. Finally, indomethacin (IND) was milled using the optimized conditions as well as the control.

Results: CCC design included eight successful runs for milling IBU from the ten total runs due to powder “blowback” from the feed hopper. DoE analysis allowed the optimization of the GrindP and PushP at 75 and 65?psi. In subsequent validation experiments using the optimized conditions, the experimental D50 and D90 values (1.9 and 3.6?μm) corresponded closely with the DoE modeling predicted values. Additionally, the optimized conditions were superior over the control conditions for the micronization of IND where smaller D50 and D90 values (1.2 and 2.7?μm vs. 1.8 and 4.4?μm) were produced.

Conclusion: The optimization of a single-step air-jet milling of IBU using the DoE approach elucidated the optimal milling conditions, which were used to micronize IND using the optimized milling conditions.  相似文献   
40.
Newsvendor model is one of the most important issues in inventory models. In this paper, we investigate a newsvendor model without lead time, which have difference between distributer and wholesale/retailer. At the end of day, the residual products of newsvendor sold to a secondary market at a unit salvage value. Also, the amount of orders that cannot be met, should be paid the penalty for each unit. In addition, in each one of channels, the percent of these orders cannot be met by the distributer. Then, the newsvendor provides the difference between the amount that ordered to distributor and the amount that met in the occurrence of interruptions risk as a special order from the manufacturer, more expensive than the price of distributor. The limitations of the study are the procurement budget that used for special order. Finally, the model is applied in a real case as a numerical example to determine order amount that maximize profit and is solved by Maple 15. The Kuhn–Tucker method was used to illustrate the optimal points that have necessary condition. Also, the hessian matrix was used to illustrate the optimal points that have sufficient condition for optimization. Consequently, the considered points are global optimum. The main factor in the disruption risk that effect on the ordering amount and profit, are including the probability of appearing of disruption \((p_i)\) and a percent of ordering amount which are met in the case of appearing of disruption \((y_i)\). Therefore, the analysis of sensitivity has been done on two parameters of \(p_i\) and \(y_i\) by using contour curves. According to result of solved problem, the change of disruption appearance reduced. Finally, the proposed method besides being simple is so exact which is sensible in the solved problems.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号