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71.
Machine vision systems are increasingly being used in industrial applications because of their ability to quickly provide information on product geometry, surface defects, surface finish, and other product and process characteristics. Previous research for monitoring these visual characteristics using image data has focused on either detecting changes within an image or between images. Extending these methods to include both the spatial and the temporal aspects of image data would provide more detailed diagnostic information, which would be of great value to industrial practitioners. Therefore, in this article, we show how image data can be monitored using a spatiotemporal framework that is based on an extension of a generalized likelihood ratio control chart. The performance of the proposed method is evaluated through computer simulations and experimental studies. The results show that our proposed spatiotemporal method is capable of quickly detecting the emergence of a fault. The computer simulations also show that our proposed generalized likelihood ratio control charting method provides a good estimate of the change point and the size/location of the fault, which are important fault diagnostic metrics that are not typically provided in the image monitoring literature. Finally, we highlight some research opportunities and provide some advice to practitioners. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
72.
Solar extraction of common salt from seawater has been practiced for centuries in a rather crude manner because the process was not performed in stages to obtain a pure salt. The common practice in developing countries is to carry through with the evaporation process to the stage of dryness to facilitate harvesting the salt mix. If salt is harvested prior to the deposition of impurities during the evaporation process then the resulting bittern would provide chemicals which could have many commercial applications particularly in treatment industries. This paper describes an effective procedure for the separation of common salt and impurities. Sufficiently sensitive indicators that would signal the start and deposition of impurities in the course of the solar evaporation process were established. These indicators are particularly useful in regions where advanced desalting technology is not readily available.  相似文献   
73.
Acetosolv-solubilized lignins were characterized by their solubility in different organic solvents, Fourier transform infrared, 13C-NMR, UV, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. Solvents having a solubility parameter in the range of 10–12.7 and a hydrogen-bonding parameter in the range of 3.6–5 were considered good solvents for acetosolv lignins. Fourier transform infrared spectra of the lignins were typical for lignins containing p-hydroxy phenylpropane (H), guaiacyl (G), and syringyl (S) units. The lignins contained more conjugated and fewer nonconjugated CO groups, and the guaiacyl groups were etherified and condensed. 13C-NMR confirmed partial acetylation of the lignins and the presence of β-O-4 and β-5 linkages. Acetosolv lignins also showed the typical UV spectrum of annual plants. The effects of the acetic acid concentration and pulping time on the molecular weights of the lignins were explained with the presieving and condensation concepts. The thermal behavior of the acetosolv lignins was also studied. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   
74.
Exponential CUSUM charts are used in monitoring the occurrence rate of rare events because the interarrival times of events for homogeneous Poisson processes are independent and identically distributed exponential random variables. In these applications, it is assumed that the exponential parameter, i.e. the mean, is known or has been accurately estimated. However, in practice, the in‐control mean is typically unknown and must be estimated to construct the limits for the exponential CUSUM chart. In this article, we investigate the effect of parameter estimation on the run length properties of one‐sided lower exponential CUSUM charts. In addition, analyzing conditional performance measures shows that the effect of estimation error can be significant, affecting both the in‐control average run length and the quick detection of process deterioration. We also provide recommendations regarding phase I sample sizes. This sample size must be quite large for the in‐control chart performance to be close to that for the known parameter case. Finally, we provide an industrial example to highlight the practical implications of estimation error, and to offer advice to practitioners when constructing/analyzing a phase I sample. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
75.
Three multiparous Holstein cows in midlactation were fitted with ruminal and duodenal cannulas. Cows were used in an experiment with a 3 x 3 Latin square design to study the effect of corn processing on nutrient flow from the rumen to the duodenum and on ruminal fermentation in lactating cows. Cows were fed diets consisting of 40% forage and 60% concentrate. The only difference in dietary ingredients was the type of processed corn included at 24% of the total diet (as-fed basis). Treatments were dry-rolled corn with a bulk density of 0.54 kg/L and steam-flaked corn with a bulk density of either 0.39 kg/L or 0.31 kg/L. Ruminal fluid pH was not affected by corn processing, but steam-flaking decreased the molar percentage of acetate and increased the molar percentage of propionate. Digestibility of starch in the rumen was not affected by processing. Digestibility of starch entering the duodenum as well as apparent digestibility of starch in the total tract were increased by steam-flaking. Flow of feed and microbial N from the rumen and microbial N efficiency were not affected by grain processing. Yields of milk and milk components as well as composition of milk were not affected by grain processing.  相似文献   
76.
The Davis Growth Model (a dynamic steer growth model encompassing 4 fat deposition models) is currently being used by the phenotypic prediction program of the Cooperative Research Centre (CRC) for Beef Genetic Technologies to predict P8 fat (mm) in beef cattle to assist beef producers meet market specifications. The concepts of cellular hyperplasia and hypertrophy are integral components of the Davis Growth Model. The net synthesis of total body fat (kg) is calculated from the net energy available after accounting for energy needs for maintenance and protein synthesis. Total body fat (kg) is then partitioned into 4 fat depots (intermuscular, intramuscular, subcutaneous, and visceral). This paper reports on the parameter estimation and sensitivity analysis of the DNA (deoxyribonucleic acid) logistic growth equations and the fat deposition first-order differential equations in the Davis Growth Model using acslXtreme (Hunstville, AL, USA, Xcellon). The DNA and fat deposition parameter coefficients were found to be important determinants of model function; the DNA parameter coefficients with days on feed >100 days and the fat deposition parameter coefficients for all days on feed. The generalized NL2SOL optimization algorithm had the fastest processing time and the minimum number of objective function evaluations when estimating the 4 fat deposition parameter coefficients with 2 observed values (initial and final fat). The subcutaneous fat parameter coefficient did indicate a metabolic difference for frame sizes. The results look promising and the prototype Davis Growth Model has the potential to assist the beef industry meet market specifications.  相似文献   
77.
N-Methacryloyloxyphthalimide (NMPI) and N-methacryloyloxytetrabromophthalimide (NMTPI) were prepared by the reaction of methacrylic acid with N-hydroxy-phthalimide and N-hydroxytetrabromophthalimide, respectively. The resulting monomers were polymerized. The reactions of the resulting polymers with hydroxy and amine compounds have been studied.  相似文献   
78.
OBJECTIVE: Hospital and physician experience have been linked to improved outcomes for persons with HIV. Because many HIV-infected patients receive care in clinics, we studied clinic HIV experience and survival for women with AIDS. DESIGN: Retrospective cohort study of women with AIDS whose dominant sources of care were clinics. Clinic HIV experience was estimated as the cumulative number of Medicaid enrollees with advanced HIV who used a particular clinic as their dominant provider up to the year of the patient's AIDS diagnosis: low experience (< 20 patients), medium (20-99 patients), high (> or = 100 patients). Proportional hazards models examined relationships between experience and survival. SETTING: A total of 117 New York State clinics. PATIENTS: A total of 887 New York State Medicaid-enrolled women diagnosed with AIDS in 1989-1992. MAIN OUTCOME MEASURE: Survival after AIDS diagnosis. RESULTS: In later study years (1991-1992), patients in high experience clinics had an approximately 50% reduction in the relative hazard of death (0.53; 95% confidence interval, 0.35-0.82) compared with patients in low experience clinics. Adjusting for demographic and clinical variables, 71% of patients in high experience clinics were alive 21 months after diagnosis compared with 53% in low experience clinics. Experience and survival were not significantly associated in the early study years (1989-1990). CONCLUSIONS: In more recent years, women with AIDS receiving care in high experience clinics survived longer after AIDS diagnosis than those in low experience clinics, providing further evidence of a relationship between provider HIV experience and outcomes.  相似文献   
79.
Many reservoirs have been constructed throughout the world during the 20th century, with many also suffering from eutrophication. The resulting increased phytoplankton biomass in reservoirs impairs their use. Except for Lake Kinneret, the environmental status of lakes and reservoirs in the Middle East is poorly documented. Karaoun reservoir, also known as Qaroun, Qaraoun or Qarun, is the largest water body in Lebanon, having been constructed for irrigation and hydropower production. This present study reviews Karaoun reservoir, including its characteristics, uses, water quality and phytoplankton succession, to assess the environmental status of the reservoir on the basis of the few existing previous publications about the reservoir. Since 2004, which is 39 years after its construction, the reservoir is considered to be hypereutrophic, with low phytoplankton biodiversity and regular blooms of toxic cyanobacteria. The nutrient and trace metal concentrations would not prevent use of the reservoir for a drinking water supply for Beirut, as is currently being planned, although not all the micropollutants in the lake were documented. Karaoun reservoir is compared to other monitored lakes and reservoirs around the Mediterranean Sea. They share annual toxic cyanobacteria blooms of Aphanizomenon ovalisporum and of Microcystis aeruginosa. The phytoplankton composition and succession of Karaoun reservoir is more similar to El Gergal reservoir (Spain) than nearby natural lakes such as Lake Kinneret (Israel) and Lake Trichonis (Greece). Phytoplankton diversity in Karaoun reservoir was the lowest, due to higher nutrient concentrations and a larger decrease in water level in the dry season. Karaoun reservoir represents an interesting example of the potential response of the phytoplankton community in other lakes and reservoirs during the drought periods expected to occur as a result of global climate change.  相似文献   
80.
The most significant feature of Nanofiber electrospinning is its capability of producing very fine Nanofiber mats which can be suitable as oil absorbent. This paper presents an investigation of oil adsorption and retention of poly(vinyl chloride) (PVC) Nanofiber mat absorbent. The emphasis is on the numerical modeling of the oil sorption capacity and the factors affecting it such as the packing density and the Nanofiber diameter. Finally, the mechanism of absorbent property enhancement and the ways to improve performance and fracture toughness for oil sorption are discussed. To enhance the oil sorption, it was suggested to add a low percentage of cellulose acetate (CA) and assess the performance of various Nanofibers as absorbent material. When the results of these studies were compared to results that of PVC Nanofiber mat, it was shown that PVC/CA 8% blend absorbs oil more efficiently.  相似文献   
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