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   104篇
  免费   2篇
电工技术   2篇
化学工业   6篇
金属工艺   3篇
机械仪表   3篇
建筑科学   1篇
能源动力   5篇
轻工业   5篇
无线电   15篇
一般工业技术   28篇
冶金工业   18篇
自动化技术   20篇
  2023年   1篇
  2021年   4篇
  2020年   2篇
  2019年   1篇
  2018年   4篇
  2015年   1篇
  2014年   1篇
  2013年   3篇
  2012年   2篇
  2011年   4篇
  2010年   2篇
  2009年   8篇
  2008年   7篇
  2007年   5篇
  2006年   4篇
  2005年   2篇
  2004年   5篇
  2003年   5篇
  2002年   4篇
  2001年   5篇
  2000年   1篇
  1999年   1篇
  1998年   8篇
  1997年   4篇
  1996年   5篇
  1995年   1篇
  1994年   1篇
  1992年   3篇
  1991年   3篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1980年   1篇
  1976年   3篇
  1974年   1篇
  1969年   1篇
排序方式: 共有106条查询结果,搜索用时 15 毫秒
71.
K Yokoo  S Ono 《Vacuum》1982,32(5):265-268
A new type of high-speed ion pump using a multipactor cathode is proposed and the experimental results, obtained with the first trial pump, are described. The multipactor cathode has excellent characteristics as an electron source in order to obtain increased pumping speed of an ion pump, namely: (1) since it is a cold cathode made of pure metal, such as Al, it does not contaminate the vacuum condition, (2) the electron emission density is high, (3) the supply of electrons can be greatly increased in comparison with that of any other supply method, (4) the electrons can be supplied easily into a very wide area.This proposal is to make a high-speed ion pump by combining such an attractive cathode with a normal ion pump. The experimental results showed that the maximum pump current per unit pump volume reached up to 30 times that of a normal ion pump in vacuum conditions of less than 10?4 Pa.  相似文献   
72.
In the autoresonant peniotron interaction, all of the electrons will be able to give almost all of their kinetic energy to an electromagnetic wave, resulting in a conversion efficiency of nearly 100%, if the condition of Vp=C is satisfied in an interaction circuit and the initial velocity ratio of electrons is correctly given as a function of the electron kinetic energy. A quadrupole circuit is proposed in which the above circuit condition is usually satisfied and the RF electric field distribution in a cross section is suitable for the peniotron interaction at the fundamental cyclotron frequency. The design procedure for the test tube with the circuit and some simulation results concerned with the tube's operation are described  相似文献   
73.
A solid oxide fuel cell (SOFC)–polymer electrolyte fuel cell (PEFC) combined system was investigated by numerical simulation. Here, the effect of the current densities in the SOFC and the PEFC stacks on the system's performance is evaluated under a constant fuel utilization condition. It is shown that the SOFC–PEFC system has an optimal combination of current densities, for which the electrical efficiency is highest. The optimal combination exists because the cell voltage in one stack increases and that of the other stack decreases when the current densities are changed. It is clarified that there is an optimal size of the PEFC stack in the parallel-fuel-feeding-type SOFC–PEFC system from the viewpoint of efficiency, although a larger PEFC stack always leads to higher electrical efficiency in the series-fuel-feeding-type SOFC–PEFC system. The 40 kW-class PEFC stack is suitable for the 110 kW-class SOFC stack in the parallel-fuel-feeding type SOFC–PEFC system.  相似文献   
74.
We propose a safe exchange mechanism involving indivisible goods and divisible goods. A typical situation is an exchange involving goods and money in a person-to-person trade in an Internet auction. Although the Internet and agent technologies have facilitated world-wide trade, we sometimes encounter risky situations, such as fraud, in the process of exchanges involving goods and money. This problem is becoming more serious with the growing popularity of person-to-person trade. One of the reasons why fraud is becoming widespread is that obtaining a new identifier in a network is cheap. This makes it almost impossible to exclude malicious agents from trade. One solution is to impose an entry fee. However, if the entry fee is too high, it will discourage newcomers from starting deals. To resolve the conflict between safety and convenience, we developed three exchange mechanisms that can guarantee against defection from a contract. Two of them reduce the entry fee by integrating multiple deals and controlling the flow of goods and money. The other reduces the entry fee by incorporating a third-party agent into the exchange process. We examine the lower bound of the entry fee for both of these mechanisms and describe a calculation method by which this value can be obtained in linear time. Our results show that the described mechanism can effectively reduce the lower bound of the entry fee.  相似文献   
75.
In this paper, we propose a novel medium for interactions based on an interpersonal psychological approach referred to as ‘naïve psychology’. We adopt the visual assessment of clustering tendency (VAT) to naïve psychology for the visual understanding of other people. The VAT algorithm produces a visual display that can be used to assess clustering tendencies in a set of persons (notions) by reconstructing a digital image representation of a square relational dissimilarity matrix for its set. This algorithm clearly represents two types of imbalanced situations in naïve psychology: crisp and fuzzy. The visual image of a balanced or imbalance situation is useful for a deeper human understanding.  相似文献   
76.
This article presents an asynchronous algorithm for solving distributed constraint optimization problems (DCOPs). The proposed technique unifies asynchronous backtracking (ABT) and asynchronous distributed optimization (ADOPT) where valued nogoods enable more flexible reasoning and more opportunities for communication, leading to an important speed-up. While feedback can be sent in ADOPT by COST messages only to one predefined predecessor, our extension allows for sending such information to any relevant agent. The concept of valued nogood is an extension by Dago and Verfaille of the concept of classic nogood that associates the list of conflicting assignments with a cost and, optionally, with a set of references to culprit constraints. DCOPs have been shown to have very elegant distributed solutions, such as ADOPT, distributed asynchronous overlay (DisAO), or DPOP. These algorithms are typically tuned to minimize the longest causal chain of messages as a measure of how the algorithms will scale for systems with remote agents (with large latency in communication). ADOPT has the property of maintaining the initial distribution of the problem. To be efficient, ADOPT needs a preprocessing step consisting of computing a Depth-First Search (DFS) tree on the constraint graph. Valued nogoods allow for automatically detecting and exploiting the best DFS tree compatible with the current ordering. To exploit such DFS trees it is now sufficient to ensure that they exist. Also, the inference rules available for valued nogoods help to exploit schemes of communication where more feedback is sent to higher priority agents. Together they result in an order of magnitude improvement.  相似文献   
77.
C‐axis‐aligned crystalline‐oxide semiconductor field‐effect transistor (CAAC‐OS FET) can be scaled down to a width and a length of 60 nm. We fabricated an organic light‐emitting diode (OLED) display with more than 5000 ppi, which is required in virtual reality (VR) display applications, using CAAC‐OS FETs as the backplane.  相似文献   
78.
Consequence finding has been recognized as an important technique in many intelligent systems involving inference. In previous work, propositional or first-order clausal theories have been considered for consequence finding. In this paper, we consider consequence finding from a default theory, which consists of a first-order clausal theory and a set of normal defaults. In an extension of a default theory, consequence finding can be done with the generating defaults for the extension. Alternatively, all extensions can be represented at once with the conditional answer format, which represents how a conclusion depends on which defaults. We also propose a procedure for consequence finding and query answering in a default theory using the first-order consequence-finding procedure SOL. In computing consequences from default theories efficiently, the notion of TCS-freeness is most important to prune a large number of irrational tableaux induced by the generating defaults for an extension. In order to simulate the TCS-freeness, the refined SOL calculus called SOL-S(Γ) is adopted using skip preference and complement checking. This research is supported in part by JSPS Grant-in-Aid for Scientific Research (No. 17300051)  相似文献   
79.
Maintenance of the red blood cell volume is a fundamental aspect of ensuring oxygen supply to the tissue. Recombinant human erythropoietin (rHuEPO) was approved for marketing in Japan in 1990 for the treatment of anemia in patients on dialysis. Recombinant human erythropoietin caused a significant increase in hemoglobin (Hb) levels in patients on dialysis. However, not all have a good response to rHuEPO therapy; the causes of rHuEPO failure include iron deficiency, infection, uremia, and interaction of some drugs. Juzen-taiho-to (TJ-48), a mixture of extracts from 10 medicinal herbs, has been used traditionally to treat patients with anemia, anorexia, or fatigue. To clarify the effect of TJ-48 on erythropoietin-resistant anemia, we studied the effect of TJ-48 in patients on hemodialysis with erythropoietin-resistant anemia. We divided 42 end-stage renal disease patients on hemodialysis with erythropoietin-resistant anemia (Hb<10.0 g/dL with rHuEPO 9000 U/wk or 15 U/kg/wk treatment) into 2 groups as follows: a TJ-48-treated group (TJ-48 group, 7.5 g/d, n=22) and a TJ-48 nontreated (control group, n=20). At the beginning of this study, there was no significant difference between the groups in age, sex, serum creatinine, blood urea nitrogen, serum iron, and ferritin. After 12 weeks of treatment, the Hb level had significantly increased from 8.4 +/- 1.1 to 9.5 +/- 1.3 g/dL (P=0.0272) in the TJ-48 group. C-reactive protein (CRP) had significantly decreased from 1.4 +/- 1.7 to 0.6 +/- 0.8 mg/dL (P=0.0438). There was a significant negative correlation between Hb and CRP in the TJ-48 group (r(2)=0.121, P=0.0066). In contrast, in the control group, Hb and CRP showed no significant changes throughout this study. Nor was there a significant correlation between Hb and CRP in the control group. In conclusion, TJ-48 was effective in improving erythropoietin-resistant anemia in end-stage renal disease patients. This effect was, at least in part, due to the anti-inflammatory effect of TJ-48 in patients on hemodialysis.  相似文献   
80.
In the mouse, oogonia enter the prophase of the first meiotic division and differentiate into oocyte while developing in the fetal ovary. Shortly after birth, all oocytes are arrested in the dictyate stage of late prophase in the developing follicles; a small number of follicles reach the ovulatory stage; the rest are lost by apoptosis. The resumption of meiotic division and nuclear progression to metaphase II (oocyte maturation) occur in the ovulatory follicles. In this article we review recent morphological data that have clarified how cytokines and glycosaminoglycans (GAGs) are involved in mouse follicular development, atresia, and maturation during oogenesis, as exogenous/endogenous factors. (1) Microvascular networks and angiogenic factors (epidermal growth factor; GAGs) are deeply involved in selective mouse oocyte growth beyond approximately 20-30 microm in diameter. (2) Gonadotropin-inducible neuronal apoptosis inhibitory protein may indirectly affect oocyte survival as a result of the inhibition of apoptotic granulosa-cell death during folliculogenesis. (3) The pattern of oocyte degeneration depends on follicle and oocyte developmental stages, and follicle stimulating hormone accelerates the process of degeneration of oocytes. (4) The process of degeneration of mouse oocytes/eggs is modulated by tumor necrosis factor-alpha that is accumulated in the expanded cumulus during oocyte maturation. (5) A colloidal iron-positive substance was detected in the intercellular spaces of follicular tissue, especially in the cumulus mass. Cells located where the cumulus mass and granulosa cell layer interwound became enlarged during the resumption of oocyte meiosis. Colloidal iron-positive substances accumulated extensively within the intercellular spaces of the enlarged 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