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21.
 One of the quality parameters of chicory (Cichorium intybus L.) is its slightly bitter taste which is caused by sesquiterpene lactones. As the quality of chicons is highly dependent on the quality of the roots, the effects of the cultivation conditions of the roots on the levels of sesquiterpene lactones in chicons were investigated. Roots from a collection of 11 commercially available and 2 experimental chicory cultivars were grown at five different locations with two nitrogen manuring levels to evaluate the differences in sesquiterpene lactone levels as measured with enzyme-linked immunosorbent assays (ELISAs). There were significant differences (P<0.001) between cultivars in both lactucopicrin and lactucin-like (lactucin, 8-deoxylactucin and their 11β,13-dihydro derivatives) sesquiterpene lactone levels. In addition, a significant (P=0.006 and P=0.019, respectively) effect of additional nitrogen manuring was observed on the levels of lactucopicrin and lactucin-like sesquiterpene lactones. The interaction of cultivar with nitrogen manuring had a significant (P=0.013) effect on the level of lactucin-like sesquiterpene lactones. Furthermore, the lactucopicrin level was significantly influenced by the interactions of the cultivar with the nitrogen manuring level (P<0.001), with the location (P=0.001) and with both the nitrogen manuring level and location (P<0.001). The results indicate that it may be possible to influence the level of the bitter sesquiterpene lactones and, consequently, to influence the taste of chicons by cultivar choice and/or cultivation location and conditions. Received: 17 December 1996  相似文献   
22.
An evolutionary algorithm that constructs recurrent neural networks   总被引:33,自引:0,他引:33  
Standard methods for simultaneously inducing the structure and weights of recurrent neural networks limit every task to an assumed class of architectures. Such a simplification is necessary since the interactions between network structure and function are not well understood. Evolutionary computations, which include genetic algorithms and evolutionary programming, are population-based search methods that have shown promise in many similarly complex tasks. This paper argues that genetic algorithms are inappropriate for network acquisition and describes an evolutionary program, called GNARL, that simultaneously acquires both the structure and weights for recurrent networks. GNARL's empirical acquisition method allows for the emergence of complex behaviors and topologies that are potentially excluded by the artificial architectural constraints imposed in standard network induction methods.  相似文献   
23.
A series of azulene–carbazole–2,1,3-benzothiadiazole (BTD) conjugated terpolymers were synthesized and their electrochemical and electrochromic properties were studied. The terpolymer containing a small amount of BTD units exhibits significantly higher electrochromic contrast and faster switching speed than azulene–carbazole alternating copolymer under low potentials because the BTD units act as electron acceptors, facilitating electron removal from azulene and carbazole units (electron donors) upon oxidation and hence leading to a lower oxidation potential. A complementary electrochromic device (ECD) was fabricated using the terpolymer as the anodically coloring layer and poly(4-styrene sulfonic acid)-doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) as the cathodically coloring layer. The ECD exhibits black-to-transmissive electrochromism as the absorption bands of the two polymers are complementary to each other in covering the whole visible region and they can be switched simultaneously under relatively low potentials.  相似文献   
24.
 The effects of sample preparation on the amount of some sesquiterpene lactones, i.e. bitter compounds, extracted from chicory (Cichorium intybus L.) have been studied. Sample preparation was performed using water or a citric acid solution both with and without cellulolytic and pectolytic enzymes. The concentrations of sesquiterpene lactones in the samples were measured by enzyme-linked immunosorbent assay (ELISA) and by high-performance liquid chromatography (HPLC). The greatest amounts of sesquiterpene lactones were obtained by treatment of the chicory samples in water in the presence of the enzymes. Evidence was obtained that both free and glucosylated sesquiterpene lactones are measured in the specific ELISAs. Received: 28 February 1996/Revised version: 10 June 1996  相似文献   
25.
Modified rice bran oil (RBO) and modified mustard oil (MO) were prepared by adding oleic acid and oxidized oil separately. The physical and chemical indices like dielectric constant, viscosity, peroxide value (PV), acid value (AV), free fatty acids (FFA), iodine value (IV), and saponification value (SV) of pure and modified RO and MO were determined and correlated. Dielectric constant and viscosity were found to decrease in a non-linear fashion with increase in temperature (30°C–75°C). The dependence of dielectric constant and viscosity with temperature was investigated using model empirical equations. The dielectric variation was studied using Akerlof and Oshry’s model equations, which exhibited high dependency of R2 ranges from 0.99 to 0.997. The behaviour of viscosity with temperature was studied with Wright’s equation and the correlation coefficient (R2) was found to be 0.998. Model equations were developed, which relates dielectric constant with IV, SV, and PV with the regression coefficients R2 = 0.955, 0.936, and 0.994, respectively. The developed equations can be used in processing, pipelining, and to predict the parameters at a desired temperature. On comparing the correlations between the physical and chemical properties of the oil samples, RBO and its modified forms exhibited more oxidative stability than modified MO.  相似文献   
26.
News frames can influence how people think about disease. In a pair of studies, we demonstrate how contemporary news outlets frame cancer and how exposure to common frames can affect news audiences' perceptions of those who suffer from cancer. First, we examine the current landscape of frame usage in online cancer news, employing frames ideally suited to the depiction of health and disease. We compare our results with previously published research in this news domain. Second, we employ these frames in a multimessage experiment to assess the influence of cancer news framing on individuals' perceptions about cancer, cancer interventions, and those with cancer. We conclude with a discussion of implications for framing research and health news production.  相似文献   
27.
This study evaluated the effectiveness of packaging using a microencapsulated β‐cyclodextrin and trans‐cinnamaldehyde complex incorporated into a base chitosan matrix on the shelf life of fresh‐cut melon (Cucumis melo L. var. Reticulatus Naud) group Inodorus that were coated with a multilayered coating system using a polypropylene tray (Ziploc®) with (i) Ziploc® lid, (ii) Saran® wrap and (iii) plain cheesecloth and stored at 4 °C for 15 days. The multilayered antimicrobial coating improved the shelf life of fresh‐cut melon (up to 15 days), compared with the controls (7 days). Coated samples were firmer, maintained colour and total carotenoids content and showed less weight loss than the controls (P < 0.05). Among the packaging treatments, the Ziploc® lid was the most effective in maintaining shelf life. This study demonstrates the application of a new generation of edible coating using natural antimicrobial agents by means of the layer‐by‐layer assembly.  相似文献   
28.
Failure analysis plays a major role in all areas of the semiconductor company especially during product development cycle, 1st silicon stage, or in wafer processes and fabrication as well as assembly and package development. Different companies have different FA flows but all FA steps will need to start with fault isolation. Fault isolation is the step to narrow down the focus area of a failing component or product to a manageable area that will allow us to (a) improve success of finding the defect that is causing the failure and, (b) significant speed up turn-around time for analysis.This paper provides an overview of all the available failure analysis on fault isolation methodologies and tools, for device/product level and expanding to package/assembly and PFA level isolation. The aim of the paper is to provide sufficient depth to each topic including some case studies to emphasize the key points related to each methodology. The tutorial will also cover some future directions/roadmaps.  相似文献   
29.
Chlorination continues to be widely used by the fresh-cut industry for washing and disinfecting minimally processed fruits and vegetables. However, as chlorination has been reported to produce unhealthy by-products such as, chloramines and trihalomethanes, many alternative methods have been reported in the literature. This study examined the use of silver and hydrogen peroxide as possible alternative to chlorination. The results revealed an obvious bactericidal effect of hydrogen peroxide, silver and their combination on spoilage organisms. Combination of electrochemically generated silver (5 ppm) and hydrogen peroxide (0.4 ppm) caused significant (P < 0.05) reduction in the total plate count (0.87 log), Pseudomonas (2.66 logs), Enterobactericeae (1.61 logs) and yeast and mould (1.60 logs) immediately after washing in comparison to water washed shredded lettuce. However, washing with chlorinated water (5 ppm) under same conditions revealed insignificant reduction in TPC (0.17 log), Pseudomonas (0.60 log), Enterobactericeae (0.15 log) or yeast and mould (0.81 log) counts. Results revealed also that both sources of silver (electrochemical silver and silver nitrate) have similar disinfecting effects, however, electrochemical silver maintained the quality of washed lettuce.  相似文献   
30.
Abstract

Vitamin A deficiency (VAD) is one of the most prevalent micronutrient deficiencies that disproportionately affects low income populations in developing countries. Traditional breeding and modern biotechnology have significant potential to enhance micronutrient bioavailability in crops through biofortification. Bananas (Musa spp.) are economically important fruit crops grown throughout tropical and sub-tropical regions of the world where VAD is most prevalent. Some banana genotypes are rich in provitamin A carotenoids (pVACs), providing an opportunity to use bananas as a readily available vehicle for provitamin A delivery. This review summarizes the progress made in carotenoid research in bananas relative to banana diversity and the use of conventional breeding and transgenic approaches aimed at banana biofortification to address vitamin A deficiency. Existing reports on sampling strategies, pVAC retention and bioavailability are also evaluated as essential components for a successful banana biofortification effort. The wide variability of pVACs reported in banana cultivars coupled with recent advances in unraveling the diversity and genetic improvement of this globally important but often-neglected staple fruit crop underscores their importance in biofortification schemes.  相似文献   
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