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   34篇
  免费   5篇
化学工业   10篇
金属工艺   1篇
建筑科学   5篇
轻工业   11篇
石油天然气   3篇
无线电   2篇
一般工业技术   4篇
冶金工业   1篇
自动化技术   2篇
  2023年   1篇
  2022年   1篇
  2021年   3篇
  2020年   4篇
  2019年   1篇
  2018年   5篇
  2017年   3篇
  2016年   4篇
  2013年   2篇
  2012年   1篇
  2009年   1篇
  2008年   1篇
  2007年   1篇
  2006年   1篇
  1995年   1篇
  1985年   2篇
  1984年   1篇
  1983年   3篇
  1982年   1篇
  1981年   2篇
排序方式: 共有39条查询结果,搜索用时 781 毫秒
1.
The overall aim of this study is to identify factors that influence architects' demotivation in design firms. After a review of extant literatures in design management, project management, and organisational behaviour, a list of 43 demotivating criteria was produced and used in a questionnaire survey. Analyses included reliability analysis, Mann–Whitney U and Kruskal–Wallis tests, demotivation severity index (DSI) computation and exploratory factor analysis. Results show an underlying factor structure of seven demotivating factors that include ‘organisational injustice’, ‘project induced stress’, ‘dysfunctional design team’, ‘poor interpersonal relationships’, ‘perceived career decline’, ‘negative leadership behaviours’ and ‘poor organisational culture’. Comparing these demotivational factors with motivational factors identified from previous related research, this study confirms that demotivation and motivation are on the same pole. In addition, what causes motivation or demotivation is a function of individual frame of reference. This implies that the presence or absence of a factor might cause motivation or demotivation depending on an individual frame of reference. Positive attention to the identified factors in relation to individual personality differences therefore helps to remove impediments that could affect employees' well-being such as being downcast, dispirited, depressed and despondent. The study would help directors and managers of design firms to develop a healthy workforce through recognition and eradication of the identified demotivating factors using some of the suggested solutions.  相似文献   
2.
This study investigated the potential cardiovascular health benefits of leavened bread produced from wheat flour that contained 1%, 2% and 3% additions of leafy vegetable powders obtained from Amaranthus viridis (AO), Solanum macrocarpon (SM) or Telfairia occidentalis (TO). Dried breads were extracted with water at 60 °C followed by analysis for total polyphenolic content (TPC), as well as in vitro inhibitions of angiotensin‐converting enzyme and renin activities. HPLC analysis of the bread extracts indicated the presence of mainly rutin, gallic acid, myricetin and caffeic acid. TPC of the vegetable‐fortified breads was significantly (< 0.05) higher (5.8–7.6 mg gallic acid equivalent, GAE/g) than that of control bread (5.5 mg GAE/g). Oral administration of 100 mg dried extract/kg body weight to spontaneously hypertensive rats led to reductions (up to 42 mmHg) in systolic, diastolic and mean arterial blood pressure in comparison with 20 mmHg for the control bread.  相似文献   
3.
This study focuses on the rheological and physiochemical characterization of three samples of light crude oil and fuel oil from the United Arab Emirates. The dependence of density on temperature ranging from 20 to 200°C was determined. Also, the impact of temperature was investigated on viscosity, shear stress τ, shear rate, yield stress, and thixotropic behavior, and characterized by the Haake RheoStress. The exponential decrease of viscosity over temperature range was modeled using Arrhenius equation. The shear stress–viscosity data revealed that crude oil A solely exhibited Newtonian behavior while crude oils B and C and fuel oil followed the Herschel-Bulkley model.  相似文献   
4.
African traditional beverages are widely consumed food‐grade liquids processed from single or mixed grains (mostly cereals) by simple food processing techniques, of which fermentation tops the list. These beverages are very diverse in composition and nutritional value and are specific to different cultures and countries. The grains from which home‐processed traditional beverages are made across Africa are often heavily contaminated with multiple mycotoxins due to poor agricultural, handling, and storage practices that characterize the region. In the literature, there are many reports on the spectrum and quantities of mycotoxins in crops utilized in traditional beverage processing, however, few studies have analyzed mycotoxins in the beverages themselves. The available reports on mycotoxins in African traditional beverages are mainly centered on the finished products with little information on the process chain (raw material to final product), fate of the different mycotoxins during processing, and exposure estimates for consumers. Regulations targeting these local beverages are not in place despite the heavy occurrence of mycotoxins in their raw materials and the high consumption levels of the products in many homes. This paper therefore comprehensively discusses for the 1st time the available data on the wide variety of African traditional beverages, the mycotoxins that contaminate the beverages and their raw materials, exposure estimates, and possible consequent effects. Mycotoxin control options and future directions for mycotoxin research in beverage production are also highlighted.  相似文献   
5.
Activity concentrations of the naturally occurring radionuclides like (238)U, (232)Th and (40)K in 400 soil samples collected from four major towns across the northern region of Namibia have been determined using gamma-ray spectrometry with the objective of providing baseline data on the radiation level in the region. The average concentrations of radionuclides in the towns vary from 7.5 +/- 2.3 to 14.2 +/- 3.3 Bq kg(-1) for (238)U, 5.8 +/- 2.6 to 24.9 +/- 6.1 Bq kg(-1) for (232)Th and 52.1 +/- 28.7 to 380.1 +/- 112.9 Bq kg(-1) for (40)K. These concentrations were used to calculate the mean absorbed dose rate and the mean annual effective dose in the region. The low value of 21 +/- 16 microSv obtained for the mean annual effective dose indicates that the region has normal background radiation.  相似文献   
6.
7.
Changes in the chemical and nutritional composition of naturally fermented soy nono were studied at ambient temperature (27 ± 2°C) for 72h. The differently fermented soy nono samples were collected at 6 h intervals and analysed for chemical, proximate and mineral composition using standard laboratory procedures. Biochemical changes in the fermenting soy nono showed a drop in pH from 6.90 to 4.09 while titratable acidity (lactic acid equivalent) increased from 0.42 to 1.82% after 72 h of natural fermentation. The moisture, carbohydrate and fat contents decreased from 93.45 to 92.70, 1.52 to 0.60 and 2.18 to 0.87 % respectively while total solids, ash and protein contents increased from 6.55 to 7.30, 0.23 to 0.74 and 2.62 to 5.09 % respectively. Results reveal that the calcium, iron and magnesium contents in fermenting soymilk increased from 52.86 to 71.43, 28.00 to 40.00 and 7.66 to 8.87 mg/l respectively within time intervals of 0 to 54 h and then decreased to 65.00, 28.00 and 7.83 mg/l respectively till the end of fermentation period while the zinc content increased from 4.42 to 6.75 mg/l throughout the fermentation period. It was evident that there was increase in protein, calcium, magnesium, zinc and iron contents during natural fermentation of soymilk.  相似文献   
8.
应用近红外光谱技术在线监测工业产品质量时,会出现环境条件变化或仪器的部件如探头或光纤更换的情况,使原模型不再具有原来的预测效果,但是完全从头开始采集数据重新建立新模型工作量大,造成原来宝贵的模型和数据的浪费。为了解决这一矛盾,本文以一种中草药口服液中多糖含量、可溶性固形物含量及pH 为研究对象,利用近红外光谱技术对其进行实时在线检测,研究了主从机分辨率不同的光谱之间的模型转移。模型转移过程利用已建模完成并成功上线应用的模型为原模型,在不能获取原主仪器和从仪器一一对应的标准标样的条件下,找到虚拟标样建立转移矩阵。以直接标准化法结合主成分分析降维作为模型转移方法,以质量指标化学参考值与预测值间的相对误差为指标筛选最佳模型。模型转移结果显示,多糖模型预测值与化学参考值间的相对误差可控制在10%以内,可溶性固形物相对误差在5%以内,pH 相对误差在3%以内。在线生产使用表明,转移的模型同原模型一样可有效应用于在线、快速对质量指标做出准确的预测。结果表明,本文提出的采用虚拟标样的模型转移方法对于无法获得主从机一一对应的标准标样的情况下的模型转移,是一个可行的有效方法。  相似文献   
9.
Over 75 pc of 138 patients prospectively studied tolerated field block local anaesthesia for inguinal herniorrhaphy. This tolerance was, however, lower in the younger age groups. There were few complications and patients were discharged within 24 to 72 hours.  相似文献   
10.
Organics and trace metals of the resin fraction of Nigerian crude oil were analysed in order to characterise the fossil fuel. The crude oil samples were deasphaltened by n-pentane, while maltene fraction was fractionated into its components (saturates, aromatics and resin) using column chromatography. The organic compounds and elemental concentrations of the resin fraction were investigated using Fourier Transform Infrared Spectroscopy and Inductively Coupled Plasma Optical Emission Spectrometry respectively. The infrared spectra showed characteristic bands containing polar functional groups expected confirming that the resin was purely eluted. The elemental concentrations were found to be high compared to other fractions and was confirmed by their T-test values. Zinc had the highest mean concentration of 32.13 ± 35.66 mg/kg, while Mn had the least (1.14 ± 0.17 mg/kg). Results indicated that processing of the crude oil resin may cause catalyst poisoning/fouling, corrosion of equipment/pipelines. Therefore, adequate consideration of these trace metals must be taken before processing.  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