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Multimedia Tools and Applications - In recent years, several technologies have been utilized to bridge the communication gap between persons who have hearing or speaking impairments and those who...  相似文献   
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Capital budget evaluation plays a crucial role in financial management. This places a firm in a competitive position. Recent development points to the need for implementing capital budgeting in construction organizations due to the capital-intensive nature of construction business. The aim here is to investigate the trends in the practice of capital budget evaluation among construction contractors operating in Hong Kong over a 20-year period. A longitudinal survey approach is used; four cross-sectional surveys were conducted between 1994 and 2014. The findings indicate that ‘formal financial evaluation’ is the most common technique used for capital budget evaluation. In addition, the practice of capital budget evaluation is more pronounced in the large-sized firms. A comparative analysis of the results of the four surveys reveals that there are variations in the degree and frequency of use of capital budget evaluation techniques over the study period. Further research is needed to understand the challenges associated with the use of sophisticated capital budget evaluation techniques in the construction industry of Hong Kong.  相似文献   
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The present study aims at the removal of copper from industrial wastewater by using a low-cost adsorbent. Activated periwinkle shell carbon (PSC) was prepared and characterized for various physiochemical properties. To determine copper removal capacity, the performance of PSC was compared with commercial activated carbon (CAC) and a mixture of activated periwinkle shell carbon and commercial activated carbon (PSC:CAC) in a ratio 1:1. The effect of adsorbent dose, contact time, pH, agitation speed and adsorbent particle size was studied for adsorption of copper from wastewater under batch conditions. The result obtained showed that PSC competes favourably with CAC. The maximum adsorption capacity was observed for PSC:CAC with 88.12% removal at an optimal pH of 8. The PSC and CAC had 84.19% removal and 85.15% removal, respectively. The equilibrium data obtained fitted both the Langmuir and the Freundlich models. Good correlation coefficients were obtained for the pseudo-second-order kinetic model.  相似文献   
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The adsorption of Cr (VI) from aqueous solution onto nanoparticles hematite (α-Fe2O3) of different morphologies synthesized by acid hydrolysis, transformation of ferrihydrite, sol gel methods has been investigated. The hematite particle sizes were in the range 15.69-85.84 nm and exhibiting different morphologies such as hexagonal, plate-like, nano-cubes, sub-rounded and spherical. The maximum adsorption capacity of Cr (VI) was found to be in the range 6.33–200 mgg?1 for all hematite samples. The kinetics of sorption was rapid, reaching equilibrium at 45–240 minutes. Sorption kinetics and equilibria followed pseudo-second order and Langmuir adsorption isotherm models. The rate constants were in the range 0.996–2.37×10?2 g/mg/min for all samples. The maximum adsorption was attained at pH 3.0, while adsorption decreased as the pH increased from pH 3.0 to 10.0. The study revealed that the hematite with plate-like morphology has the highest adsorption capacity. The sorption process has been found to be feasible following a chemisorption process, and adsorption of Cr (VI) onto hematite nanoparticles was by inner sphere surface complexation due to low desorption efficiency in the range 9.54–53.4%. However, the result of ionic strength revealed that the reaction was by outer sphere complexation. This study showed that morphologies play a vital role in the adsorption capacities of samples of hematite in the removal of Cr (VI) from aqueous solution.  相似文献   
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Precipitable water vapour (PWV) retrieved from ground-based Global Navigation Satellite System (GNSS) stations over Nigeria from 2013 to 2014 is compared with PWV from a satellite remote-sensing technique (Atmospheric Infrared Sounder [AIRS]) and a global reanalysis model (ERA-Interim) over Nigeria. The PWV for AIRS and ERA-Interim was obtained from the respective data providers. PWV estimates from the different techniques were grouped into daily estimates and were matched and re-grouped into monthly and seasonal averages. The performance of the PWV techniques was evaluated using recommended indices by the World Meteorological Organization. All datasets gave a reasonable estimate of PWV when compared against GNSS at daily, monthly, and seasonal scales, the agreement between the various techniques was better at monthly and seasonal scales. In terms of bias, precision, accuracy, fitness, and reliability of measurement, ERA-Interim outperformed the other technique and could possibly be a complementary data source to GNSS PWV, although as a reanalysis, it cannot be used for meteorology. The AIRS night-time (or descending) retrieval was ranked next to the ERA-Interim; AIRS daytime (or ascending) retrieval agreed less with GNSS PWV when compared with ERA Interim and night-time AIRS. These results indicate that GNSS PWV as observed over the study area represents a remarkable dataset for further evaluation studies and serves as a useful source of humidity information to improve the water cycle in numerical weather models for varying applications in the region.  相似文献   
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ABSTRACT

This contribution summarizes the temporal intermediates produced during the ozonation of phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol, as followed by liquid chromatography coupled to a time of flight mass spectrometer (LC-MS-TOF). A 2 × 10?3 M solution of the phenolic compounds was ozonated in a sintered glass reactor at an ozone dose of 0.14 mg/min (O2/O3 flow 10 mL/min). Identified intermediates showed that catechol pathway was the predominant route for phenol oxidation with acrylic acid being the end product. Hydroxylative dechlorination of 2-chlorophenol also gave catechol, and the reaction products were similar to that of phenol. Hydroxylation and ring opening via the 4-chlorocatechol pathways were the predominant route for the ozonation of 4-chlorophenol, while 2,4-dichlorophenol followed both hydroxylation and hydroxylative dechlorination mechanism. Several novel intermediates and coupling products were identified and reaction schemes leading to breakdown products are provided for each phenolic compound.  相似文献   
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Protein isolates and concentrates were obtained from defatted cashew nut powder by two methods: alkaline extraction-isoelectric precipitation (IP) and alkaline extraction-methanol precipitation (MP). The functional properties of cashew nut protein isolates, concentrates and powder were significantly different (p < 0.05). Cashew nut protein isolate (CNPI) had higher water and oil absorption capacities (2.20 ml/g and 4.42 ml/g, respectively), emulsifying stability index (447%), foam capacity and stability (45% and 55%, respectively), and least gelation capacity (13.5%) than cashew nut protein concentrate (CNPC), which was also higher than that of defatted cashew nut powder (DCNP). However, emulsifying activity index (12.45%) and bulk density (0.31) of CNPI were lower than that of CNPC, which were also lower than that of DCNP. The water solubility of CNPI (95%) and CNPC (95%) was not significantly different (p > 0.05) among the samples, but was significantly different (p < 0.05) from that of DCNP (75%). The CNPI, CNPC and DCNP showed decreasing solubility with decreasing pH, with the minimum solubility being observed at a pH range of 4.0–4.5, confirming the isoelectric point of cashew proteins. However, higher water solubility, emulsifying activity, and foaming property were observed at an alkaline pH than at an acidic pH in all samples.  相似文献   
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