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21.
The literature suggests that individuals will be healthier if they live in Active Community Environments that promote exercise and activity. Two key elements of such environments are walkability and safety. Examining data from the National Health and Nutrition Examination Survey III, 1988-1994 and using a multilevel analysis, we found that individuals who live in counties that are more walkable and have lower crime rates tended to walk more and to have lower body mass indices (BMIs) than people in less walk-able and more crime-prone areas, even after controlling for a variety of individual variables related to health. Among lifelong residents of an area, lesser walk-ability and more crime were also associated with respondents reporting weight-related chronic illness and lower ratings of their own health. The effect of high crime rates was substantially stronger for women than for men, and taking this interaction into account eliminated gender differences in walking, BMI, weight-related chronic conditions, and self-reported poor health. The results suggest that to promote activity and health, planners should consider community walkability, crime prevention, and safety.  相似文献   
22.
The efficiency of cyclones varies widely with the size of particles and complex mathematic formulations are used for predicting the collection efficiency of a single particle size. Numerical integration of the latter, in conjunction with the appropriate in each case input particle size distribution, or direct use of nomographs if lognormal input particle size distribution can be assumed, yields the overall efficiency. In either case, no information is available regarding the size distribution of the penetrating particles. As shown in this paper, lognormal input particle size distributions yield lognormal output particle size distributions. Based on this and on the analysis of functional relations, a set of nomographs is developed directly yielding the mean diameter and standard deviation of penetrating particles as a function of the input particle size distribution parameters and key cyclone design and operating conditions. The above set the stage for the rigorous computation of the size-specific emissions from cyclones and the overall and size-specific efficiencies of secondary control systems that may follow. This analysis is in line with current trends, which, on the basis of health considerations, place emphasis on the size-specific rather than on the overall particle emissions.  相似文献   
23.
Car crashes are a major cause of death and serious injury to children but most analyses of risk are based on US data. The Australian context is different in at least three ways: (1) the proportion of passenger-side airbags, a potential risk to children in front seats, is much lower; (2) unlike in the US, Australian airbags are designed to work with restrained passengers; (3) restraint use for children 0-12 years is high (>90%). Official data drawn from Victorian crash records (n=30,631) were used to calculate relative risks of death or serious injury for children (0-3 years, 4-7 years; 8-12 years) traveling in passenger cars during 1993-1998 and 1999-2004. Over 90% were reportedly wearing a restraint, and 20% were traveling in the front seat. For children under 4 years traveling in the front seat, the relative risk of death was twice as great as when traveling in the rear, and that of serious injury was 60% greater. The relative risk of death whilst traveling in the front seat was almost four times greater for children aged under 1 year. We suggest that serious consideration should be given to mandating rear seating for children, particularly those aged 4 and under.  相似文献   
24.
The potential use of ultrasound measurements, combined with other physical measurements, has been investigated. The good relationship between soluble solids content (SSC) and ultrasonic wave velocity reported in the literature being confirmed by our study, our main goal was to evaluate the added value of ultrasound measurements around 25 MHz for the determination of biochemical compounds responsible of organoleptic quality of mangoes. Among the main sugar constituents of mango juice, only sucrose content prediction was improved by combining SSC and ultrasonic waves velocity using a PLS model (R2 = 0.81, RMSECV = 12.3, bias = 0.10, RPD = 2.3) when compared to the linear model with SSC only (R2 = 0.75, SEP = 14.05, bias = 0.08). The same conclusion was obtained for titratable acidity PLS model using whole fruit hardness, SSC and ultrasonic wave velocity (R2 = 0.82, RMSECV = 1.84, bias = 0.02, RPD = 2.4) compared to the linear model with fruit hardness only (R2 = 0.78, SEP = 2.07, bias = 0.02). However, the added value of ultrasound measurements was not always found to be significant (P = 0.05) when a Wilcoxon statistical tests was conducted on the residuals of the linear and PLS models for both sucrose and titratable acidity.  相似文献   
25.
26.
BACKGROUND: Coconut (Cocos nucifera L.) water is a refreshing tropical drink whose international market has recently been growing. However, little is yet known about its physicochemical composition, particularly its aroma. This study set out to characterise the volatile profile of water from five coconut varieties. RESULTS: Aroma compounds were characterised by headspace solid phase microextraction gas chromatography (HS‐SPME‐GC) analysis. An experimental design was established to optimise SPME conditions, leading to an equilibration time of 10 min followed by an extraction time of 60 min at 50 °C. Accordingly, immature coconut water from WAT (West African Tall), PB121 (MYD × WAT Hybrid), MYD (Malayan Yellow Dwarf), EGD (Equatorial Guinea Green Dwarf) and THD (Thailand Aromatic Green Dwarf) palms was analysed and described. Ketones were mainly present in the Tall and Hybrid varieties, whereas aldehydes were most abundant in the Dwarf palms. Tall coconut water was characterised by a high lactone content. THD exhibited a high ethyl octanoate level. The cluster analysis of the volatile fraction from the five coconut cultivars was found to be related to their genetic classification. CONCLUSION: The volatile compounds of immature coconut water from five varieties were characterised for the first time. Volatile profile analysis could be a useful tool for the selection of Dwarf coconut varieties, which are mainly consumed as a beverage. Copyright © 2012 Society of Chemical Industry  相似文献   
27.
A highly localized source of low-frequency shear waves can be created by the modulated radiation force resulting from two intersecting quasi-continuous-wave ultrasound beams of slightly different frequencies. In contrast to most other radiation force-based methods, these shear waves can be narrowband. Consequently, different frequency-dependent effects will not significantly affect their spectrum as they propagate within a viscoelastic medium, thereby enabling the viscoelastic shear properties of the medium to be determined at any given modulation frequency. This can be achieved by tracking the shear wave phase delay and change in amplitude over a specific distance. In this paper we explore the properties of short duration (dynamic) low-frequency shear wave propagation and study how the shear displacement field depends on the excitation conditions. Our investigations make use of the approximate Green's functions for viscoelastic media, and the evolution of such waves is studied in the spatiotemporal domain from a theoretical perspective. Although nonlinearities are included in our confocal source model, just the properties of the fundamental shear component are examined in this paper. We examine how the shear wave propagation is affected by the shear viscosity, the coupling wave, the spatial distribution of the force, the shear speed, and the duration of the modulated wave. A method is proposed for estimating the shear viscosity of a viscoelastic medium. In addition, it is shown how the Voigt model paremeters can be extracted from the frequency-dependent speed and attenuation.  相似文献   
28.
The analysis of periodic or repetitive motions is useful in many applications, such as the recognition and classification of human and animal activities. Existing methods for the analysis of periodic motions first extract motion trajectories using spatial information and then determine if they are periodic. These approaches are mostly based on feature matching or spatial correlation, which are often infeasible, unreliable, or computationally demanding. In this paper, we present a new approach, based on the time- frequency analysis of the video sequence as a whole. Multiple periodic trajectories are extracted and their periods are estimated simultaneously. The objects that are moving in a periodic manner are extracted using the spatial domain information. Experiments with synthetic and real sequences display the capabilities of this approach.  相似文献   
29.
This study extended incivility research beyond the confines of the workplace by exploring the relationships between incivility, work-to-family conflict and family support. Data collected from 180 employees from various organizations in Singapore showed that incivility is not a rare phenomenon in Asian cultures. Employees experienced more incivility from superiors than coworkers or subordinates, and these experiences were related to different outcomes. Coworker-initiated incivility was associated with decreased coworker satisfaction, increased perceptions of unfair treatment, and increased depression. On the other hand, superior-initiated incivility was associated with decreased supervisor satisfaction and increased work-to-family conflict. Results also revealed that employees with high family support showed stronger relationships between workplace incivility and negative outcomes, compared with employees with low family support. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
30.
The problem we study in this paper arises from the washing step of hospital sterilisation services. Washers in the washing step are capable of handling more than one medical device set as long as their capacity is not exceeded. The medical device set sizes and arrival times to the sterilisation service may be different, but they all have the same washing duration. Thus, we model the washing step as a batch scheduling problem where medical device sets are treated as jobs with non-identical sizes and release dates, but equal processing times. The main findings we present in this paper are the following. First, we study two special cases for which polynomial algorithms are presented. We then develop a 2-approximation algorithm for the general problem. Finally, we develop a MILP model and compare it with another MILP model from the literature. Computational results show that our MILP model outperforms the model from the literature.  相似文献   
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