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排序方式: 共有27条查询结果,搜索用时 31 毫秒
1.
We present the comparison of atmospheric concentrations of eleven currently used pesticides (HCB, alpha-HCH, gamma-HCH, trifluraline, mecoprop, phosalone, atrazine, carbofuran, carbaryl, diuron and isoproturon) measured in remote (Aubure), rural (Colmar) and urban (Strasbourg) areas of Alsace and Vosges regions (cast France). Pesticides samples were collected simultaneously on two of the three sites during the summer season of 1993 and 1994, using a Hi-Vol sampler with Whatman filter paper and XAD-2 resin. The particle and gas phases were collected separately during 24 h. The relative importance of local emissions and local, regional and long distance transport on the contamination of the atmosphere in the three environments (remote, rural and urban) were investigated. To facilitate the interpretation of the results, the alpha/gamma-HCH ratio was used as a tracer of pesticide emissions.  相似文献   
2.
'Pena-Shokeir syndrome' in a newborn male infant   总被引:1,自引:0,他引:1  
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3.
With the de facto transformation of technology into nano-technology, more and more functional components can be embedded on a single silicon die, thus enabling high degree pipelining operations such as those required for multimedia applications. In recent years, system-on-chip designs have migrated from fairly simple single processor and memory designs to relatively complicated systems with multiple processors, on-chip memories, standard peripherals, and other functional blocks. The communication between these IP blocks is becoming the dominant critical system path and performance bottleneck of system-on-chip designs. Network-on-chip architectures, such as Virtual Channel (2004), Black-bus (2004), Pirate (2004), AEthereal (2005), and VICHAR (2006) architectures, emerged as promising solutions for future system-on-chip communication architecture designs. However, these existing architectures all suffer from certain problems, including high area cost and communication latency and/or low network throughput. This paper presents a novel network-on-chip architecture, Pipelining Multi-channel Central Caching, to address the shortcomings of the existing architectures. By embedding a central cache into every switch of the network, blocked head packets can be removed from the input buffers and stored in the caches temporally, thus alleviating the effect of head-of-line and deadlock problems and achieving higher network throughput and lower communication latency without paying the price of higher area cost. Experimental results showed that the proposed architecture exhibits both hardware simplicity and system performance improvement compared to the existing network-on-chip architectures.  相似文献   
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5.
Response surface methodology was used to study the process optimization of cationic percentage through grafting diallyldimethylammonium chloride (DADMAC) into cassava starch. Based on Box–Behken design, quadratic models were developed to correlate the synthesis variables: concentration of DADMAC (A), concentration of initiator (B), and polymerization temperature (C), to the responses of cationic percentage (y). Analysis of variance (ANOVA) revealed that the concentration of initiator was the most significant variable for the response. The optimum preparation conditions for starch grafted polyDADMAC were 14% cationic using 31 g DADMAC/10 g dry starch of concentration DADMAC, a polymerization temperature of 74°C, and 4.92 g cerric ammonium nitrate/10 mL of initiator concentration.  相似文献   
6.
Clinical diagnosis is one of the areas in which flow cytometry (FCM) has gained wide popularity and FCM now plays a crucial role in several aspects of medical hematology. It has progressively replaced many traditional laboratory tests due to its greater accuracy, sensitivity and rapidity. Unfortunately, among the very large number of its potential applications, only a minority of flow cytometric protocols have been standardized. Numerous factors are responsible for variation in analytical conditions and may affect results obtained by FCM. All these variables can be schematically divided into three major groups: factors related to the biological samples, immunological and accessory reagent factors and factors associated with the use of instruments. The quality control program must monitor and evaluate all aspects of the procedure. This includes the following main aspects: 1) performance of the flow cytometer, 2) specimen collection, transportation and maintenance of its integrity, 3) reagents, particularly monoclonal antibodies and 4) sample measurements, data acquisition and their interpretation. Procedures described here are designed to assess all the settings which affect the reliability, reproducibility and sensitivity of the cytometer in order to ensure identical conditions on a daily basis.  相似文献   
7.
A case of advanced extrauterine pregnancy involving the rectum and with passage of fetal limb through the anus is presented. The patient probably had a heterotopic gestation.  相似文献   
8.
Traditionally, two isolated sequential stopping rules are employed for monitoring the time of occurrence of an event (T) and the magnitude of an event (X) . Recently, several researchers recommend monitoring T and X together using some unified approach. A unified approach based on combinations of two statistics, one for monitoring T and the other for X , is often more efficient. Likewise, a new approach of simultaneous monitoring of location and scale parameters of a process, combining a max and a distance based statistics, is recently introduced in literature. Motivated by such emerging concepts, we design a new scheme combining a Max‐type and a Distance‐type schemes, referred to as the MT scheme, to monitor T  and X simultaneously and efficiently. It retains the advantages of both the Max‐type and the Distance‐type schemes for joint inference. The proposed scheme is very competent in detecting a shift in the process distribution of T  or X or both. Moreover, it is computationally simpler. It has nice exact expressions for design parameters. Therefore, it is easier to implement. It has a distinct advantage over its traditional counterparts in detecting moderate to large shifts. Finally, we illustrate the implementation of the proposed scheme with a real dataset of damage caused by outbreak of fire disaster.  相似文献   
9.
Wireless local area networks – or Wi-Fi networks – are proliferating in some societies. Our interest in this exploratory essay is to illustrate how ostensibly free, publicly-accessible Wi-Fi requires users to apply conventional understandings of space and place (particularly commercial spaces and places) as they make sense of some ambiguities about proper use in those places. We show, through an examination of the metaphorical terms used to describe Wi-Fi, how spatial notions are employed in an attempt to define ownership of the signal and rights to its use. We consider how place-behaviors require evaluation of legitimacy of users in public places and of hospitality of Wi-Fi providers. We observe that commercial interests underpin notions of ownership, legitimacy and hospitality of social actors in public places like coffee shops and parking lots. As researchers considering matters of participation in virtual places, we must first have some appreciation for the normative constraints and conventions that govern the commercial public places in which users access “free” Wi-Fi.  相似文献   
10.
The demand for gas turbines that accept a variety of fuels has continuously increased over the last decade. Understanding the effects of varying fuel compositions on combustion characteristics and emissions is critical to designing fuel‐flexible combustors. In this study, the combustion characteristics and emissions of methane and hydrogen‐enriched methane were both experimentally and numerically investigated under ultra‐lean conditions (Ø ≤ 0.5). This study was performed using global mechanisms with a one‐step mechanism by Westbrook and Dryer and a two‐step mechanism with an irreversible and reversible CO/CO2 step (2sCM1 and 2sCM2). Results show that the 2sCM2 mechanism under‐predicted the temperature, major species, and NOx by more than 100% under ultra‐lean conditions; thus, we proposed a modified‐2sCM2 mechanism to better simulate the combustion characteristics. The mechanisms of Westbrook, 2sCM1, and modified 2sCM2 predicted the temperature and the CO2 emission with an average deviation of about 5% from the experimental values. Westbrook and 2sCM1, however, over‐predicted the NOx emission by approximately 81% and 152%, respectively, as compared with an average under‐prediction of 11% by the modified‐2sCM2 mechanism. The numerical results using the proposed modified‐2sCM2 mechanism shows that the presence of hydrogen in the fuel mixture inhibits the oxidation of methane that led to the formation of unburned hydrocarbons in the flame. We also showed that for any given fuel compositions of H2/CH4, there is an optimum equivalence ratio at which the pollutant emissions (CO and NOx) from the combustor are minimal. Zero CO and 5 ppm NOx emissions were observed at the optimal equivalence ratio of 0.45 for a fuel mixture containing 30% H2. The present study provides a basis for ultra‐lean combustion toward achieving zero emissions from a fuel‐flexible combustor. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
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