首页 | 本学科首页   官方微博 | 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   28篇
  免费   4篇
化学工业   10篇
无线电   1篇
一般工业技术   9篇
冶金工业   8篇
自动化技术   4篇
  2021年   2篇
  2020年   2篇
  2019年   5篇
  2017年   2篇
  2016年   2篇
  2015年   2篇
  2014年   3篇
  2012年   1篇
  2011年   2篇
  2009年   1篇
  2008年   3篇
  2004年   1篇
  2001年   1篇
  1997年   2篇
  1993年   2篇
  1992年   1篇
排序方式: 共有32条查询结果,搜索用时 78 毫秒
1.
This paper addresses the discrete network design problem (DNDP) with emphasis on the environmental benefits. These benefits are traditionally quantified by emission models, which in general account for vehicle speeds, traffic flows and emission coefficients. An alternative approach for approximating the environmental impact of traffic is developed. This approach finds the route that keeps the most balanced speed profile throughout the route, which contributes to fuel consumption reduction. The paper formulates an optimization problem that includes the described approach for the DNDP. The solution of the problem consists of projects that contribute the most to the generation of such “balanced speed routes”. The paper illustrates the problem and the solution for a real-size network with a medium-size set of candidate projects.  相似文献   
2.
The removal of various organic micropollutants (OMPs), including six antibiotics (ERY, ROX, CLA, SMX, SMZ, and TMP), three pharmaceuticals (ibuprofen, salicylic acid, and diclofenac), one industrial product (BPA), and one hormone (cholesterol), was investigated in two pilot plants treating the same raw sewage of the Tel-Aviv WWTP. The effluent production by CAS-UF was 45 m3/h while that of MBR was 40 L/h. Each system's effluent constituted the feed for its RO, which comprised three RO steps after the CAS/UF and a semi-batch RO system after the MBR. Despite significant molecular differences between the selected OMPs, high removal rates were achieved after the RO stage (> 99% for macrolides, pharmaceuticals, cholesterol, and BPA, 95% for diclofenac, and > 93% removal of sulfonamides). However, low antibiotics concentrations and 28–223 ng/L residuals of ibuprofen, diclofenac, salicylic acid, cholesterol, and BPA in the MBR/RO and CAS-UF/RO permeates showed that although RO is an efficient removal solution, it cannot serve as an absolute barrier to OMPs. Therefore, additional treatment techniques should be considered to be incorporated aside the RO to ensure complete removal of such substances.  相似文献   
3.
Wheat is the staple food of Punjab province of Pakistan, which contributes more than 75% of the total national production. Accurate and timely forecasting of wheat yield is a cornerstone for monitoring food security and planning for agricultural markets, but the efficiency of the current system for near real-time forecasting should be improved. In this research paper, we developed a model to forecast wheat yield before harvest for each of eight individual districts and for Punjab province as a whole. The model uses weather and Moderate Resolution Imaging Spectroradiometer (MODIS)-derived normalized difference vegetation index (NDVI) data for 2001–2014 (14 years) to calculate Random Forest (RF) statistical models using 15 independent variables. Temperature, rainfall, sunshine hours, growing degree days, and MODIS-derived NDVI for each of the eight districts of Punjab province were used to forecast yield for the year 2014. The same independent variables were used to forecast wheat yield of the whole Punjab from 2001 to 2014 by excluding the respective year from training set. Sunshine hour data were not available for all districts and therefore we tested using temperature data and average latitude-based solar radiation as surrogates. The root mean square errors (RMSEs) of the forecast results of the whole of Punjab province were 147.7 kg ha?1 and 148.7 kg ha?1 with a mean error of less than 5% using average and generic RFs, respectively. Forecasts for individual districts showed R2 of 0.95 with RMSE of 175.6 kg ha?1 and 5.86% mean error.  相似文献   
4.
5.
DAP kinase links the control of apoptosis to metastasis   总被引:1,自引:0,他引:1  
DAP kinase is a new type of calcium/calmodulin-dependent enzyme that phosphorylates serine/threonine residues on proteins. Its structure contains ankyrin repeats and the 'death' domain, and it is associated with the cell cytoskeleton. The gene encoding DAP kinase was initially isolated as a positive mediator of apoptosis induced by interferon-gamma, by using a strategy of functional cloning. We have now tested whether this gene has tumour-suppressive activity. We found that lung carcinoma clones, characterized by their highly aggressive metastatic behaviour and originating from two independent murine lung tumours, did not express DAP kinase, in contrast to their low-metastatic counterparts. Restoration of DAP kinase to physiological levels in high-metastatic Lewis carcinoma cells suppressed their ability to form lung metastases after intravenous injection into syngeneic mice, and delayed local tumour growth in a foreign 'microenvironment' Conversely, in vivo selection of rare lung lesions following injection into syngeneic mice of low-metastatic Lewis carcinoma cells or of DAP kinase transfectants, was associated with loss of DAP kinase expression. In situ TUNEL staining of tumour sections revealed that DAP kinase expression from the transgene raised the incidence of apoptosis in vivo. DAP-kinase transfectants also showed increased sensitivity in vitro to apoptotic stimuli, of the sort encountered by metastasizing cells at different stages of malignancy. We propose that loss of DAP kinase expression provides a unique mechanism that links suppression of apoptosis to metastasis.  相似文献   
6.
Multivariate control charts are used for monitoring multiple series simultaneously, for the purpose of detecting shifts in the mean vector in any direction. In the context of disease outbreak detection, interest is in detecting only an increase in the process means. Two practical approaches for deriving directional Hotelling charts are Follmann's correction and Testik and Runger's quadratic programming. However, there has not been an extensive comparison of their practical performance. Moreover, in practice, many of the underlying method assumptions are often violated, and the theoretically guaranteed performance might not hold. In this work, we compare the two directionally sensitive approaches: a statistically based approach and an operations research solution. We evaluate Hotelling charts as well as two extensions to multivariate exponentially weighted moving average charts. We examine practical performance aspects such as robustness to often‐impractical assumptions, the amount of data required for proper performance, and computational aspects. We perform a large simulation study and examine performance on authentic biosurveillance data. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
7.
A new approach to resolve and quantify the effect of temperature on both the average, as well as the instantaneous, structure of generally symmetric molecules is presented. The method employs the efficient continuous symmetry measure, which is shown here to be capable of separating temperature-induced instantaneous disorders from other sources of distortion, such as the Jahn−Teller effect. We demonstrate the potential of the method by studying two highly symmetric molecules: adamantane and the cyclopentadienyl anion and their cationic states. Our results show that although the distortive effect of temperature is significant, it does not mask other distortion effects. Symmetry analysis provides means to quantify the extent of the distortion in each case, and is investigated from a statistical point of view. A major experimental and theoretical challenge is to resolve the Jahn−Teller effect from other environmental effects, such as solvent, solid matrix, concentration, etc. Our results provide a step forward in this direction.  相似文献   
8.
Depressive symptoms and pain are common in patients on chronic hemodialysis (HD), yet their associations with quality of life (QOL) are not fully understood. We sought to characterize the longitudinal associations of these symptoms with QOL. As part of a trial comparing two symptom management strategies in patients receiving chronic HD, we assessed depressive symptoms using the Patient Health Questionnaire‐9 (PHQ‐9), and pain using the Short Form McGill Pain Questionnaire (SF‐MPQ) monthly over 24 months. We assessed health‐related QOL (HR‐QOL) quarterly using the Short Form 12 (SF‐12) and global QOL (G‐QOL) using a single‐item survey. We used random effects linear regression to analyze the independent associations of depressive symptoms and pain, scaled based on 5‐point increments in symptom scores, with HR‐QOL and G‐QOL. Overall, 286 patients completed 1417 PHQ‐9 and SF‐MPQ symptom assessments, 1361 SF‐12 assessments, and 1416 G‐QOL assessments. Depressive symptoms were independently and inversely associated with SF‐12 physical HR‐QOL scores (β = ?1.09; 95% confidence interval [CI]: ?1.69, ?0.50, P < 0.001); SF‐12 mental HR‐QOL scores (β = ?4.52; 95% CI: ?5.15, ?3.89, P < 0.001); and G‐QOL scores (β = ?0.64; 95%CI: ?0.79, ?0.49, P < 0.001). Pain was independently and inversely associated with SF‐12 physical HR‐QOL scores (β = ?0.99; 95% CI: ?1.30, ?0.68, P < 0.001) and G‐QOL scores (β = ?0.12; 95%CI: ?0.20, ?0.05, P = 0.002); but not with SF‐12 mental HR‐QOL scores (β = ?0.16; 95%CI: ?0.050, 0.17, P = 0.34). In patients receiving chronic HD, depressive symptoms and to a lesser extent pain, are independently associated with reduced HR‐QOL and G‐QOL. Interventions to alleviate these symptoms could potentially improve patients' HR‐QOL and G‐QOL.  相似文献   
9.
Type IIB von Willebrand disease (vWD) is characterized by a selective loss of high molecular weight von Willebrand factor (vWF) multimers in plasma due to their abnormally enhanced reactivity with platelets. Several missense mutations in the platelet glycoprotein Ib (GPIb) binding domain of vWF were recently characterized that cause type IIB vWD. The effect of type IIB mutation Arg(545)Cys on vWF binding to platelet GPIb was studied using recombinant wild type (rvWFWT) and mutant rvWFR545C expressed in COS-7 cells. In the absence of ristocetin, 50% of rvWFR545C bound spontaneously to platelet GPIb and the binding increased to 70% in the presence of 0.2 mg/ml ristocetin; rvWFWT did not bind significantly under either condition. Botrocetin-induced binding of rvWFR545C was only slightly increased compared to rvWFWT. These data demonstrate that the Arg(545)Cys mutation increases the affinity of vWF for GPIb, resulting in the characteristics gain-of-function type IIB vWD phenotype.  相似文献   
10.
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