首页 | 官方网站   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   94篇
  免费   0篇
工业技术   94篇
  2022年   1篇
  2021年   8篇
  2020年   1篇
  2017年   2篇
  2016年   1篇
  2015年   3篇
  2014年   1篇
  2013年   3篇
  2012年   5篇
  2011年   13篇
  2010年   4篇
  2009年   7篇
  2008年   4篇
  2007年   4篇
  2006年   2篇
  2005年   6篇
  2004年   2篇
  2003年   2篇
  2002年   1篇
  2001年   4篇
  2000年   1篇
  1999年   2篇
  1998年   7篇
  1997年   4篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1983年   1篇
  1976年   2篇
排序方式: 共有94条查询结果,搜索用时 15 毫秒
1.
2.

The dried bean beetle, Acanthoscelides obtectus, is an economically important, worldwide pest of legume crops including dry beans, Phaseolus vulgaris. Assessment of A. obtectus infestation levels in pre-harvest field crops and post-harvest granaries is difficult to achieve because there is no effective monitoring tool for early detection so that interventions can be deployed as needed. Because A. obtectus is a generic pollen and nectar feeder, we adopted an electrophysiological (EAG) screening approach, using the antennae of female A. obtectus to identify physiologically active, volatile phytochemicals, which could then be investigated for their attractiveness to A. obtectus in laboratory behavioral assays and preliminary field tests. Of the 27 compounds tested in EAG screening, 5 compounds, i.e., methyl anthranilate, methyl eugenol, benzyl alcohol, (RS)-lavandulol, and 2-phenylethanol, elicited stronger EAG responses than the standard (1-phenylethanol). In 4-arm olfactometer bioassays, female A. obtectus preferred the olfactometer arm containing the odor of either methyl anthranilate or benzyl alcohol compared to the solvent control. In preliminary field tests using these 2 compounds as a binary mixture, at least 5 times as many beetles were caught on baited traps compared to non-baited traps. The field data also suggested that benzyl alcohol was primarily responsible for the field activity of the blend. We hypothesize that the attraction of A. obtectus to the combined benzyl alcohol/methyl anthranilate and the single benzyl alcohol baits is connected to the species` nectar- and pollen-feeding behaviour and not to its intraspecific communication. To our knowledge, this is the first evidence that A. obtectus behavior in the field can be modified by the deployment of plant-derived semiochemicals.

  相似文献   
3.
4.
With the increasing awareness of the warm asphalt technology, it is imperative to study the properties of the binders containing the warm asphalt additives thoroughly, especially since not much research has been conducted on warm asphalt binder properties to date. Also, in the recent years, researchers have observed that the SHRP rutting parameter G1/sin δ is not very effective in predicting the rutting performance of binders, especially in case of modified binders. Zero shear viscosity (ZSV) has been evaluated to determine its effectiveness in predicting the rutting behavior of asphalt binders. Thus, in this paper, the ZSV of five asphalt binders with and without the warm asphalt additives, Asphamin® and Sasobit®, were calculated using the different models and test methods available in literature. From the test results, it was observed that the addition of the warm asphalt additives increased the ZSV of all the five binders used in this study. It was also observed that the different test methods gave different ZSV values, and that the selection of the test methods and the testing parameters are crucial parameters.  相似文献   
5.
In this paper we propose a Connection Admission Control (CAC) algorithm to provide Quality of Service (QoS) in UMTS Terrestrial Radio Access Networks (UTRAN). In UTRAN, the main QoS requirement is to ensure low packet delays. The CAC algorithm works with priority scheduling, which is used for QoS differentiation. We give a detailed investigation on the performance implications of applying priority scheduler. We provide novel closed-form formulae which are fast, simple and accurate enough for practical implementation of the CAC. A comprehensive performance evaluation study with illustrative numerical examples is also presented. The results are validated by simulations.  相似文献   
6.
A domain of attraction (DOA) analysis has been performed for a simplified model of the primary circuit of a pressurized water nuclear power plant, the Paks Nuclear Power Plant in Hungary. A simple two dimensional autonomous hybrid differential equation model of the controlled primary circuit has been developed for the purpose of the stability analysis that contains both continuous and discrete variables. It has been shown that the DOA of the controlled system encapsulates the operating domain for any positive value of the considered feedback gain of the power controller and the reactor power. However, the gain has a great impact on the dynamics of the controlled system that is also investigated, and a practically advantageous domain of the gain has been determined.  相似文献   
7.
The primate orbitofrontal cortex is a site of convergence of information from primary taste, olfactory, and somatosensory cortical areas. We describe the responses of a population of single neurons in the orbitofrontal cortex that responds to fat in the mouth. The neurons respond, when fatty foods are being eaten, to pure fat such as glyceryl trioleate and also to substances with a similar texture but different chemical composition such as paraffin oil (hydrocarbon) and silicone oil [Si(CH3)2O)n]. This is evidence that the neurons respond to the oral texture of fat, sensed by the somatosensory system. Some of the population of neurons respond unimodally to the texture of fat. Other single neurons show convergence of taste inputs, and others of olfactory inputs, onto single neurons that respond to fat. For example, neurons were found that responded to the mouth feel of fat and the taste of monosodium glutamate (both found in milk), or to the mouth feel of fat and to odor. Feeding to satiety reduces the responses of these neurons to the fatty food eaten, but the neurons still respond to some other foods that have not been fed to satiety. Thus sensory-specific satiety for fat is represented in the responses of single neurons in the primate orbitofrontal cortex. Fat is an important constituent of food that affects its palatability and nutritional effects. The findings described provide evidence that the reward value (or pleasantness) of the mouth feel of fat is represented in the primate orbitofrontal cortex and that the representation is relevant to appetite.  相似文献   
8.
Nowadays electrical waste (EW) recycling has become a practical way to provide raw material for new devices. Computer parts such as memory, motherboard or other parts contain large amount of metals from which the recovery of precious metals and copper represents the highest economical potential. With a proper chemical treatment these metals can be efficiently extracted and separated from the actual waste. For this task a specially designed leaching reactor, equipped with a perforated rotating drum, was used. This work is aimed at investigating if computational fluid dynamics (CFD) tools can be efficiently applied to model the chemical reactor used to dissolve the metals from the EW. First a hybrid CFD-compartment approach was developed to describe the dissolution process in the leaching reactor while the CFD models were used to model the hydrodynamics of the process. Based on the detailed model containing momentum and component mass balance the developed simulator could be used to enhance the performance of the existing reactor system. For the modelling studies COMSOL Multiphysics was used as CFD software.  相似文献   
9.
Sulfamate (NHSO(3)(-)) groups are critically important structural elements of the glycosaminoglycans heparin and heparan sulfate (HS). Experimental conditions are presented for detection of the sulfamate (1)H NMR resonances in aqueous solution. NMR spectra reported for N-sulfoglucosamine (GlcNS) and the synthetic pentasaccharide drug fondaparinux demonstrate the broad utility of the sulfamate group (1)H chemical shifts to reflect differences in molecular structure. The sulfamate protons also provide an efficient route for detection of (15)N chemical shifts through proton-nitrogen correlations measured with the heteronuclear single quantum coherence (HSQC) experiment. The HSQC spectra of GlcNS, fondaparinux, and the low-molecular weight heparin enoxaparin illustrate the power of the (1)H and (15)N chemical shifts of the sulfamate NH groups for the structural characterization of heparin and HS.  相似文献   
10.
The first Hungarian MEN IIB (multiplex endocrine neoplasia) syndrome is reported with the short summary of the literature about the pathogenesis and diagnosis of medullary thyroid carcinoma, presenting 80% in sporadic, 20% in hereditary form. The appearance of the patients alone (marfanoid stature, bulky lips, and ganglioneuromatosis of the tongue) may be almost enough for the presumption for the diagnosis of MEN IIB: For screening and preventing the clinical manifestation of the very aggressive medullary carcinoma in the relatives of the patient, the genetic screening is indispensable. The costs of the genetic screening and early treatment of the patients are much lower than the expenses of the traditional annual biochemical screening and the--delayed, often only supportive--treatment of the clinically manifested illness.  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-23

京公网安备 11010802026262号