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   147篇
  免费   6篇
综合类   1篇
化学工业   37篇
金属工艺   5篇
机械仪表   7篇
建筑科学   14篇
能源动力   14篇
轻工业   14篇
水利工程   3篇
石油天然气   1篇
无线电   6篇
一般工业技术   33篇
冶金工业   3篇
原子能技术   3篇
自动化技术   12篇
  2023年   1篇
  2022年   4篇
  2021年   6篇
  2020年   6篇
  2019年   10篇
  2018年   6篇
  2017年   6篇
  2016年   3篇
  2015年   3篇
  2014年   6篇
  2013年   15篇
  2012年   13篇
  2011年   9篇
  2010年   13篇
  2009年   11篇
  2008年   8篇
  2007年   13篇
  2006年   3篇
  2005年   7篇
  2004年   3篇
  2003年   3篇
  2002年   2篇
  1996年   1篇
  1995年   1篇
排序方式: 共有153条查询结果,搜索用时 0 毫秒
141.
Background Research is considered the essence of graduate engineering education, but knowledge about the engineering graduate student research experience is scarce in literature. Some studies that examine graduate engineering education suggest that students are experiencing educational deficiencies that can affect the research experience. Thus, exploring engineering graduate student research proficiency is warranted. Purpose (Hypothesis ) This work begins to earnestly answer the research questions “How proficient are engineering graduate students in research?” and “What factors affect the research proficiency of these students?” Design /Method In order to answer the two research questions specifically for the Georgia Institute of Technology Environmental Engineering graduate program, current students in the program participated in two surveys. Survey questions were designed to measure students' perceptions of their research proficiency and to aid in determining student academic motivations tied to proficiency. Results Many students indicated that they lacked research preparation upon beginning graduate study and during the first year of study, lacked development in important research skills like statistics and communicating in writing, and were somewhat hindered in research organization and progress. Regarding academic motivations, students generally valued personal advancement and enrichment over paper publication. Doctoral students overall indicated more preparation with respect to several aspects of research and more value placed on paper publication than did master's students. Conclusions The surveys provided important findings regarding student research proficiency for the engineering graduate program in question. These findings encourage the exploration of engineering graduate student research proficiency on a broader scale in future studies.  相似文献   
142.
Boron removal from geothermal waters by electrocoagulation   总被引:2,自引:0,他引:2  
Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm(2), but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%.  相似文献   
143.
A novel edge detection algorithm for color images was described in this paper. In the proposed method, smoothness of each pixel in color image is firstly calculated by means of similarity relation matrix and is normalized to maximum gray level. In other words, color image in three-dimensional color spaces is mapped into one dimension. Accordingly the edges are performed in such a way that pixels lower than thresholds are assigned to be edge. Thus with proposed method, edge pixels in a color image are detected simultaneously without any complex calculations such as gradient, Laplace and statistical calculations.  相似文献   
144.
The design and synthesis of a necklace‐like nitrogen‐doped tubular carbon (NTC) are presented by growing microporous polyhedral ZIF‐8 particles and a uniform layer of ZIF‐8 on sacrificial ZnO tetrapods (ZTPs). Oxygen vacancies together with defect regions on the surface of the ZTPs result in the formation of ZIF‐8 polyhedra in conjunction with a very thin shell. This necklace‐like NTC structure has a high N content, very large surface area, ultrahigh microporosity, and quite high electrical conductivity. NTC‐based symmetrical supercapacitor and zinc‐ion capacitor (ZIC) devices are fabricated and their electrochemical performance is measured. The NTC supercapacitor shows an ultrahigh rate capability (up to 2000 mV s?1) and promising cycle life, retaining 91.5% of its initial performance after 50 000 galvanostatic charge–discharge cycles. An aqueous ZIC, constructed using the NTC, has a specific capacitance of 341.2 F g?1 at a current density of 0.1 A g?1 and an energy density of 189.6 Wh kg?1 with a 2.0‐V voltage window, respectively. The outstanding performance is attributed to the NTC high N‐doping content, a continuous “polyhedral 3D hollow” architecture and the highly porous microtubular arms exhibiting very high surface area.  相似文献   
145.
The constants of the extraction equilibrium and the distribution for dichloromethane as an organic solvent having low dielectric constant of metal cations with chiral Schiff bases, benzaldehydene-(S)-2-amino-3-phenylpropanol (I), ohydroxybenzaldehydene-( S)-2-amino-3-phenyl-propanol (II), benzaldehydene-(S)-2- amino-3-methylbutanol (III) with anionic dyes [4-(2-pyridylazo)-resorcinol mono sodium monohydrate (NaPar), sodium picrat (NaPic) and potassium picrat (KPic)] and some heavy metal chlorides were determined at 25 ºC. All the ligands have given strongest complexation for NaPar. In contrast, similar behaviour for both alkali metal picrates is not apparent in the complexation of corresponding ligands.  相似文献   
146.
主要介绍了触发器的设计和性能。为了分析撞击型触发器的几何特征对于轴向冲击荷载作用下耗能构件的抗挤压性能的影响,对其进行数值分析。该耗能构件由一个平盖加一个帽形顶部剖面构成。将触发器视为一个在帽形剖面上具有半圆形横截面的突起物,采用有限元软件LS-DYNA模拟所有的挤压作用。结果显示:在挤压力峰值和轴向冲击荷载作用下的构件耗能能力上,触发器的引入非常有效。同时发现,通过改变触发器的位置和几何尺寸,可以控制构件的挤压响应。  相似文献   
147.
148.
In the present study, beta-type low elastic modulus Ti–Ta–Zr–Co alloy foams were manufactured by powder metallurgy-mechanical alloying based space holder route for hard tissue implant purposes. Ta was included to the alloy for low elastic modulus beta-Ti phase stabilisation in order to prevent stress shielding effect between implant and bone. Zr was introduced for corrosion resistance. Co addition was lowered the sintering temperature of the alloy, provided easier machining, and introduced aging capacity. Electrochemical anodisation (oxidation) surface treatment was carried out to produce a surface oxide film in order to improve the corrosion resistance and bioactivity. Corrosion properties of the surface passive oxide film were investigated in artificial saliva. Digital radiography and computed tomography studies were used for three-dimensional defect and pore structure characterisation.  相似文献   
149.
In recent years,with the development of technology,interest in microelectronics and thin film devices has increased considerably.Future improvements in microele...  相似文献   
150.
In this study, the treatment of pistachio processing wastewater (PPW) by electro-oxidation method was investigated. Ti/Pt-plated electrodes were used for the anode material, and stainless steel electrodes were used for cathode material. Experimental studies were carried out in batch mode. Stirring speed, supporting electrolyte species and concentration, initial pH value, current density, temperature and dilution ratio were selected as experimental parameters effecting removal efficiency. In Ti/Pt electrode experimental studies on the optimum conditions, chemical oxygen demand (COD), total organic carbon (TOC) and total phenols (TP) removal efficiencies were obtained, respectively, as 99.98%, 70.74% and 100%, and energy consumption value was obtained as 297.5 kW-h/m3 (12.39 kW-h/kg COD, 51.29 kW-h/kg TOC and 64.68 kW-h/kg TP). As a result of the experimental studies, the PPW can be treated by electro-oxidation. Given the results of removal efficiency and energy consumption values, it was concluded the electro-oxidation using Ti/Pt anode very appropriate treatment of PPW.  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