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   8篇
  免费   5篇
化学工业   3篇
建筑科学   1篇
矿业工程   3篇
一般工业技术   4篇
冶金工业   1篇
自动化技术   1篇
  2019年   2篇
  2018年   1篇
  2017年   2篇
  2016年   3篇
  2015年   1篇
  2014年   1篇
  2009年   1篇
  1990年   1篇
  1983年   1篇
排序方式: 共有13条查询结果,搜索用时 34 毫秒
1.
Mine Water and the Environment - Correct values for radium have been rewritten in Table 1 and Table 2. Correct radium units in Figure 2(c) are Bq/L (Becquerel per liter). The same applies to...  相似文献   
2.
Solvent‐assisted crystallization has previously been employed to remove long‐chain saturated fatty acids (≥ 18 carbons) from animal fat to improve its cold temperature biofuel properties. The same technology can be used for removing long‐chain saturated fatty acids (SFA) from animal fats for human consumption, but SFA remaining (i.e., 14:0 and 16:0) are more atherogenic than longer chain SFA. In the present study, an easy and efficient method was developed using short‐path distillation prior to solvent‐assisted crystallization for the more complete removal of SFA from beef tallow, and for the first time reports the distillation and crystallization behavior of polyunsaturated fatty acid biohydrogenation products (PUFA‐BHP). Shorter chain SFA methyl esters (i.e., 14:0 and 16:0) were efficiently removed at 90 °C, 9.3 Pa, with a rotor speed of 70 rpm and either two cycles of distillation at 90 drops/min or three cycles at 110 drops/min. Stearic acid (18:0) was then effectively removed by crystallization at ?20 °C using a sample to methanol ratio of 1:10. The remaining fraction enriched with PUFA‐BHP (i.e., rumenic acid, c9,t11‐18:2, and its precursor vaccenic acid, t11‐18:1) have potential use in disease model (i.e., cell culture and animal) studies to help further elucidate their bioactivity and mode of action, and may in the future have functional food or nutraceutical potential.  相似文献   
3.
The mining of coal in the Upper Silesian Coal Basin and the relatively recent closure of many of these mines during the past two to three decades has affected surface and underground water quality. Regulations in Poland are designed to protect active mining operations rather than water quality and water environment. Dewatering mechanisms in abandoned coal mines and characteristics of water pumped (quality, temperature) are discussed.  相似文献   
4.
5.

Coal mine discharges in several European countries were investigated as part of the European Commission’s MANAGER project. The emphasis of the project was identification of priority pollutants and potential remedial approaches. The main identified priority pollutants were sulphate (all countries) and iron (all countries except Greece). High concentrations of chloride (particularly in Germany and Poland) were associated with discharge of saline mine waters linked to the presence of fossil sea water; these mine waters also had high boron concentrations, in contrast to chloride-rich waters in UK that are linked to recent sea water inflow. Concentrations of trace metals vary among countries, but radium is an important contaminant in barium-rich waters with low sulphate concentrations, essentially in Poland. Concentrations of trace metals and metalloids were generally low because of their relative scarcity in coal strata and adsorption onto ferric oxides and hydroxides, but they still often exceeded the environmental quality thresholds.

  相似文献   
6.
Studies of the lead and cadmium content of soils and vegetables from 126 allotments in 12 towns in a polluted region of Poland are described. Metal concentrations in parsley, celery, carrots and red beet were determined using AAS. In most cases, metal concentrations in soils and vegetables exceeded accepted standards and concentrations found in rural regions. A total of 756 vegetable samples were studied and only 170 met the standard for lead and 17 for cadmium. The lowest lead content was found in parsley roots and the highest in celery leaves. Cadmium content between species did not differ greatly and the highest concentrations were recorded for celery. The metal intake by the consumer was also calculated using questionnaire data concerning vegetable consumption. In relation to the reference area, the metal intake in the polluted area was 2-5 times higher for lead and 2-16 times higher for cadmium. The main species responsible for the high metal concentrations were carrots and red beet. Replacing carrots and red beet with the same species grown in an unpolluted region would reduce the consumer's metal intake from vegetables considerably.  相似文献   
7.
8.
In this note we delve some more into the formal analogy of quantum mechanics and filtering theory, and we integrate the DMZ equation by transforming it into a Schroedinger equation that can be integrated in the standard way.  相似文献   
9.
Incremental equal channel angular pressing (I-ECAP) is a severe plastic deformation process used to refine grain size of metals, which allows processing very long billets. As described in the current article, an AZ31B magnesium alloy was processed for the first time by three different routes of I-ECAP, namely, A, BC, and C, at 523 K (250 °C). The structure of the material was homogenized and refined to ~5 microns of the average grain size, irrespective of the route used. Mechanical properties of the I-ECAPed samples in tension and compression were investigated. Strong influence of the processing route on yield and fracture behavior of the material was established. It was found that texture controls the mechanical properties of AZ31B magnesium alloy subjected to I-ECAP. SEM and OM techniques were used to obtain microstructural images of the I-ECAPed samples subjected to tension and compression. Increased ductility after I-ECAP was attributed to twinning suppression and facilitation of slip on basal plane. Shear bands were revealed in the samples processed by I-ECAP and subjected to tension. Tension–compression yield stress asymmetry in the samples tested along extrusion direction was suppressed in the material processed by routes BC and C. This effect was attributed to textural development and microstructural homogenization. Twinning activities in fine- and coarse-grained samples have also been studied.  相似文献   
10.
Biohydrogenation intermediates (BHI) including conjugated linoleic acid (CLA) isomers are formed during ruminal biohydrogenation of polyunsaturated fatty acids (PUFA) in ruminants. Although many studies have examined the anticarcinogenic effects of CLA, few studies have reported the anticarcinogenic properties of BHI in their natural form found in dairy and beef fats. The present study compared the growth‐inhibitory effects of fatty acids from beef perirenal fat (PRF) or subcutaneous fat (SCF) with low or high levels of BHI in MCF‐7 human breast cancer cells. Cells were exposed for 72 h to media containing increasing doses (50 to 400 μM) of different beef fat treatments. Fatty‐acid analysis showed that BHI were readily incorporated into cell phospholipids (PL) in a treatment‐dependent manner, but higher BHI in PL did not consistently inhibit growth. Culturing with low‐BHI PRF or high‐BHI PRF did not lead to growth inhibition, but low‐BHI SCF inhibited growth, and inhibition was further increased by high‐BHI SCF. Other classes of fatty acids may, therefore, be interacting with BHI resulting in differential effects on growth inhibition in human breast cancer cells.  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