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1.
A triarylmethane dye 1 detects CN? from water and shows remarkable selectivity over other anions and dramatic color changes, in solution as well as when dyed. The pH stability of 1 in the range of 1.2–10.7 offers additional advantage in the sensing process under physiological conditions.  相似文献   
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Multiobjective Pareto optimal solutions have been generated for three grades of nylon 6 being produced in an industrial semibatch reactor. The optimal operating conditions (called preferred solutions) for these three batches are easy to implement and lead to substantial improvements over current practice. The technique used is quite general and can easily be applied to improve the operation of other industrial polymerization reactors or design better (new) reactors. Good mathematical models, which account for the important physicochemical aspects actually operative in a reactor and which have been tested on industrial data, are a prerequisite for such optimization studies. © 1995 John Wiley & Sons, Inc.  相似文献   
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Abstract: Three‐dimensional (3D) range scanning of large spaces, such as civil structures, generates an immense cloud of 3D points with inconsistent data densities due to the limited positions of the stationary scanner, inaccessible surfaces, and narrow pathways. This density variation is the dominant detrimental factor in extracting accurate scanned shapes. This article introduces an effective scan planning methodology for capturing accurate geometry from long and narrow spaces, which minimizes the need for subsequent data approximations. The technique computes an optimum scanning range for each stationary position of the scanner that limits the density variation to a user‐defined value. Three cases are proposed to define the “limited data density” and a FARO®‐LS880 laser scanner is used to illustrate the proposed approach that achieves acceptable scanning results in terms of its critical shape capturing capability, overall point cloud density, and accurate point‐based visualization. The experimental observations confirm that the accuracy of the scanned data can be improved by registering multiple partial scans with restricted density and positioning the data acquisition device close to the critical features. The latter recommended step decreases the incident angle to the world domain, which, in turn, reduces the surface occlusions and data density variations.  相似文献   
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We report synthesis of amorphous silicon oxide nano-spheres in bulk quantity by using a simple non-catalytic process based on thermal evaporation of silicon monoxide. Structural characteristics of the nano-spheres were investigated using high resolution scanning and transmission electron microscopes equipped with energy dispersive X-ray spectroscopy (EDAX). Selected area electron diffraction and EDAX analyses revealed that nano-spheres were amorphous and comprised of silicon oxide only with Si and O in an atomic ratio of ~ 1:2. Photoluminescence measurements showed that the SiOx nano-spheres had strong emission band in the blue region. Possible growth mechanism based on vapor-solid model has been discussed. The SiO vapors generated at high temperature react with O2 to form SiOx vapors which subsequently condense on the substrates (placed in the appropriate temperature zone) to form SiOx nano-spheres.  相似文献   
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The operation of ion implanted silicon position sensitive detectors at low temperatures will be described. The improved noise performance of the detector at these temperatures in both the energy and position modes will be analyzed and its implications on low energy applications will be discussed. A large part of the investigation was devoted to the study of boron implanted resistors and their noise properties both at room temperature and cryogenic temperatures.  相似文献   
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Background: Glioblastoma (GBM) is a highly aggressive cancer with poor prognosis that needs better treatment modalities. Moreover, there is a lack of reliable biomarkers to predict the response and outcome of current or newly designed therapies. While several molecular markers have been proposed as potential biomarkers for GBM, their uptake into clinical settings is slow and impeded by marker heterogeneity. Detailed assessment of prognostic and predictive value for biomarkers in well-defined clinical trial settings, if available, is scattered throughout the literature. Here we conducted a systematic review and meta-analysis to evaluate the prognostic and predictive significance of clinically relevant molecular biomarkers in GBM patients. Material and methods: A comprehensive literature search was conducted to retrieve publications from 3 databases (Pubmed, Cochrane and Embase) from January 2010 to December 2021, using specific terms. The combined hazard ratios (HR) and confidence intervals (95% CI) were used to evaluate the association of biomarkers with overall survival (OS) in GBM patients. Results: Twenty-six out of 1831 screened articles were included in this review. Nineteen articles were included in the meta-analyses, and 7 articles were quantitatively summarised. Fourteen studies with 1231 GBM patients showed a significant association of MGMT methylation with better OS with the pooled HR of 1.66 (95% CI 1.32–2.09, p < 0.0001, random effect). Five studies including 541 GBM patients analysed for the prognostic significance of IDH1 mutation showed significantly better OS in patients with IDH1 mutation with a pooled HR of 2.37 (95% CI 1.81–3.12; p < 0.00001]. Meta-analysis performed on 5 studies including 575 GBM patients presenting with either amplification or high expression of EGFR gene did not reveal any prognostic significance with a pooled HR of 1.31 (95% CI 0.96–1.79; p = 0.08). Conclusions: MGMT promoter methylation and IDH1 mutation are significantly associated with better OS in GBM patients. No significant associations were found between EGFR amplification or overexpression with OS.  相似文献   
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MXene nanomaterials have sparked significant interest among interdisciplinary researchers to tackle today's medical challenges. In particular, colloidal MXene quantum dots (MQDs) offer the high specific surface area and compositional flexibility of MXene while providing improvements to aqueous stability and material–cell interactions. The current study for the first time reports the development and application of immunoengineered tantalum-carbide (Ta4C3Tx) MQDs for in vivo treatment of transplant vasculopathy. This report comes at a critical juncture in the field as poor long-term safety of other MXene compositions challenge the eventual clinical translatability of these materials. Using rational design and synthesis strategies, the Ta4C3Tx MQDs leverage the intrinsic anti-inflammatory and antiapoptotic properties of tantalum to provide a novel nanoplatform for biomedical engineering. In particular, these MQDs are synthesized with high efficiency and purity using a facile hydrofluoric acid-free protocol and are enriched with different bioactive functional groups and stable surface TaO2 and Ta2O5. Furthermore, MQDs are spontaneously uptaken into antigen-presenting endothelial cells and alter surface receptor expression to reduce their activation of allogeneic T-lymphocytes. Finally, when applied in vivo, Ta4C3Tx MQDs ameliorate the cellular and structural changes of early allograft vasculopathy. These findings highlight the robust potential of tailored Ta4C3Tx MQDs for future applications in medicine.  相似文献   
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The effect of Saccharomyces cerevisiae yeast culture (YC, Yea-Sacc 1026) as a supplement to the high-roughage diet of buffalo calves on the rumen microbial populations, fermentation pattern and in sacco dry matter disappearance of dietary constituents was examined. A control group was fed a diet consisting of, on a dry matter basis, 2·12 kg bajra (Pennisetum typhoides) hay and 0·45 kg groundnut cake per day per calf, while the treatment group had the same diet plus 5 g YC. After feeding for 6 weeks, inclusion of YC was stopped and both groups were given the control diet for 2 weeks. At week 4 the pH in the rumen fluid (RF) was significantly higher (P<0·05) up to 6 h post-feeding in the treatment group compared with the control group. The concentrations of total, total viable and cellulolytic bacteria were increased by 41·0 (P<0·05), 33·5 and 57·4% (P<0·01), respectively, with YC supplement. The concentration of total volatile fatty acids (P<0·05), particularly at 4 h post-feeding (P<0·01) and acetate (P<0·01) and acetate to propionate ratio (P<0·05) were higher in the treatment compared with the control group. On YC supplementation, the concentration of NH3-N was decreased (P<0·05) while that of TCA-precipitable protein in RF was marginally but non-significantly increased. Withdrawal of YC from the diet reversed these effects and the rumen variables returned to values close to control levels after 2 weeks. The in sacco dry matter disappearance of dietary components was higher in the treatment compared with the control group, particularly during the first 24 h of incubation. © 1997 SCI.  相似文献   
10.
In this study, optimal vapor release rate (or pressure) histories have been generated for an industrial semi-batch nylon 6 reactor using Pontryagin's minimum principle. The batch time has been taken as the objective function, which is to be minimized. The pressure is constrained to lie between a lower and an upper limit. The temperature, a state variable, is also constrained to lie between 220°C and 270°C in order to ensure single-phase polymerization. Optimization has been carried out with a single end-point constraint (on monomer conversion) and a stopping condition (obtaining a product having a desired degree of polymerization, μn). Techniques have been developed to overcome the discontinuities present in the model, as well as to take care of state variable constraints. The effects of various physical and computational variables on the optimal pressure history and the corresponding batch time have been studied. It is found that the optimal batch time is almost 50% of the industrial value used currently. Interestingly, the optimal pressure history is quite similar qualitatively with the current practice though quantitatively there is a significant difference. Improvements in reactor operation along these lines have been reported. © 1996 John Wiley & Sons, Inc.  相似文献   
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