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1.
Controlled chemical precipitation method was used to obtain nanosized titania (TiO2) powders. XRD, DTA/TGA/DTG techniques were employed for phase analysis and to know the thermal changes taking place in precipitated precursor during heating. The effect of processing and fabrication conditions viz. calcination temperature, mold pressure and sintering temperature/time on membranes prepared from this titania powder was studied using permeability measurements. The bulk porosity, average pore size and permeability were found to decrease with increase in the molding pressure. However, an increase in the sintering period increases the bubble point and brings the diameter of the larger pores nearer to that of the average pore.  相似文献   

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Performance measures and metrics are essential for effectively managing logistics operations, particularly in a competitive global economy. The global economy is featured with global operations, outsourcing and supply chain and e-commerce. The real challenge for managers of this new enterprise environment is to develop suitable performance measures and metrics to make right decisions that would contribute to an improved organizational competitiveness. Now the question is whether traditional performance measures can be used and out of them which ones should be given priority for measuring the performance in a new enterprise environment. Some of the traditional measures and metrics may not be suitable for the new environment wherein many activities are not easily identifiable. Measuring intangibles and nonfinancial performance measures pose the greater challenge in the so-called knowledge economy. Nevertheless, measuring them is so critical for the successful operations of companies in this environment. Considering the importance of nonfinancial measures and intangibles, an attempt has been made in this paper to determine the key performance measures and metrics in supply chain and logistics operations. This is based on a literature survey and some of the reported case experiences. Suggestions for future research directions are also indicated.  相似文献   

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This paper explores the relationship between patenting and publishing in the field of nanotechnology for Chinese universities. With their growing patents, Chinese universities are becoming main technological source for nanotechnology development that is extremely important in China. Matching names of patentees to names of research paper authors in Chinese universities, we find 6,321 authors with patents, i.e. inventor–authors, and 65,001 without any patent. Research performance is measured using three indicators—publication counts, total citations and h-index received by each researcher. It is found that research performance of authors who are also inventors holding patents is better than that of those authors who do not have a patent, and that most of high quality research is performed by inventor–authors. Our findings indicate that patent-oriented research may produce better results.  相似文献   

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BACKGROUND: A criticism of conventional office or clinic-based models of care is that they focus on patients' urgent problems and do not provide the comprehensive assessments, education, and psychosocial support that vulnerable patients also need. Innovative models have emerged to address these needs. A systematic review of prospective studies involving searches of computerized databases, reviews of reference lists, and contacts with authors, was conducted to determine whether multidisciplinary teams, outreach or home care, and case management improve the quality of the care in two vulnerable populations-the terminally ill and the mentally ill. RESULTS: Literature searches identified 730 citations. 52 original articles met screening standards, and 24 studies fulfilled all criteria. Patient and caregiver satisfaction was consistently higher with innovative models. In no study was satisfaction lower. Functional, clinical, or psychological improvements were not consistently demonstrated. For mentally ill patients, multidisciplinary outreach strategies were effective in reducing inpatient hospitalizations. Costs were inadequately assessed in the studies to draw a summary conclusion. DISCUSSION: Like other interventions, health care delivery models can be assessed from an evidence-based perspective. More needs to be learned about the costs and health improvements of innovative models before we can determine whether the increased patient and caregiver satisfaction found justifies widespread use of these models. Development of a uniform set of quality outcome measures and encouragement to evaluate efforts and disseminate results will help accomplish this goal.  相似文献   

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The aim of this study was to analyze the influence of nanoporous structure of polymeric biomaterials on the in vitro osteogenic induction of human stem cells. An electronic search in three databases (MEDLINE, SCOPUS, and Web of Science) was performed for articles that were published before May 2018. In vitro studies were included if they met the following criteria: (1) the use of polymeric scaffolds (natural or synthetic); (2) the co-culture of human stem cells with the scaffold; and (3) cell viability, proliferation, and osteogenic differentiation assays. The main characteristics of the published studies were summarized, and a quality assessment tool was used to analyze methodological features. Eighty-eight potential articles were firstly retrieved. Thirteen were eligible for qualitative analysis. Only three studies characterized cell stemness. Nanostructure of the scaffolds showed a significant influence on viability, proliferation, and osteogenic differentiation of human stem cells. Combination of porosity between 72 and 93% and a large range diameter between 50 and 224 μm resulted in more remarkable cellular proliferation and differentiation. Porous polymeric scaffolds can be functionalized by stem cells leading to osteogenic induction. High standards of laboratory practice and accurate methodological reporting are essential for the credibility of the results.  相似文献   

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Li  Xin  Yao  Qiang  Tang  Xuli  Li  Qian  Wu  Mengjia 《Scientometrics》2020,125(2):1253-1274
Scientometrics - This paper aimed to provide an approach to investigate the historical roots and evolution of research fields in China by extending the reference spectroscopy year spectroscopy...  相似文献   

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Asubiaro  Toluwase 《Scientometrics》2019,120(3):1261-1287
Scientometrics - This study investigated if collaboration type, publication place, funding and author’s role affect citations received by publications from Africa. Library and Information...  相似文献   

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The study's purpose was to determine which factors influence a consumer's willingness to pay for sustainability and their intention to take action against climate change related to airports. An expanding body of literature relates to assessing whether consumers would be willing to pay for these ‘green’ practices in the aviation industry, such as biofuels or sustainable airport construction/renovations. While previous studies have experimentally examined these scenarios, we are aware of no prior research that has proposed and assessed a structural model related to determining which factors influence consumer's perspectives on ‘green’ airports. A sample of 722 eligible participants from the United States completed the study using Amazon's Mechanical Turk. We examined future time perspective, affect toward climate change, the perceived value of sustainability, and perceptions of climate change on the endogenous variables of willingness to pay for sustainability and intentions to take action against climate change. Six of the seven hypotheses proposed were supported. Affect, perceived value, and perceptions of climate change were all significant and positively related to willingness to pay, which was positively associated with intention to act. Two non-hypothesized paths, between perceived value and future time perspective, were also positively related to intention to act. The model explained 42% of the variance in willingness to pay and 66% in intention to act. These findings offer insights into what factors significantly influence these relationships as they relate to airports. Perceived value and perceptions of climate change had the largest effect sizes in the model and were significantly related to willingness to pay and intentions to act.  相似文献   

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A series of Ce1−x Fe x O2 (0 < x ≤ 0.5) catalysts were prepared by the co-precipitation method, and their catalytic performances were investigated for the total oxidation of CO and CH4 as model reactions. X-ray diffraction (XRD) and Raman spectroscopy results show that Ce1−x Fe x O2−δ solid solutions are formed with x ≤ 0.2. Ce0.9Fe0.1O2 solid solution presents superior catalytic performance for CH4 and CO oxidation, while Ce1−x Fe x O2 with x > 0.2 shows less active for CO and CH4 oxidation. The results of H2-temperature programmed reduction (H2-TPR), CH4-temperature programmed surface reaction (CH4-TPSR) and CO-TPSR reveal that, the surface oxygen of catalyst is relevant to CO oxidation, which was promoted by the oxygen vacancies formed in Ce–Fe–O solid solution, while the easier lattice oxygen migration property and the favorable reducibility of the catalysts is responsible for the promoted catalytic performance for CH4 oxidation.  相似文献   

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A grid was developed to evaluate control of serum calcium, phosphate, and parathyroid hormone levels in hemodialysis patients, based on guideline recommendations (National Kidney Foundation Kidney Disease Outcomes Quality Initiative and Canadian Society of Nephrology), and its face validity was examined in a representative sample of Canadian patients. A retrospective chart review was undertaken in hemodialysis patients from 7 Canadian units. Patients >18 years, on hemodialysis for ≥12 months, and ≥3 parathyroid hormone levels measured ≥1 month apart were included. The grid classified mineral metabolism control as optimal, suboptimal, or poor (mean of 3 measurements). Medication use, hospitalization, and Emergency Department visits were evaluated in relation to grid occupancy. A second comparative analysis of grid occupancy was undertaken on prevalent hemodialysis cases in British Columbia in 2008. Data from 268 patients (mean age 62.3 years) were analyzed. Using National Kidney Foundation Kidney Disease Outcomes Quality Initiative guidelines, 17.5%, 28.8%, and 53.7% of patients had optimal, suboptimal, and poor control, respectively, of all 3 parameters (calcium, phosphate, and parathyroid hormone). Using Canadian Society of Nephrology criteria, optimal, suboptimal, and poor control rates were 6.3%, 4.2%, and 89.5%, respectively. Poor control was a possible or a probable cause of hospitalization or Emergency Department attendance in 8 patients. Data from British Columbia in 2008 (n=1858) show optimal, suboptimal, and poor control rates of 15.8%, 24.5%, and 59.7%, respectively. Poor mineral metabolism control among Canadian hemodialysis patients is not showing improvement. The therapeutic grid is a valid tool and may help guide therapeutic decisions, quality control initiatives, and patient counseling. http://www.ukidney.com/bone‐and‐mineral‐metabolism‐resource .  相似文献   

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There is a specific nomenclature for the so-called mechanical twins or twins obtained by mechanical deformation. This nomenclature, (K 1, η 1, K 2, η 2), is due to Otto Mügge in 1889. The German mineralogist and crystallographer Mügge (1858–1932) rationalised twinning observations made by himself and by other German scientists since 1859 such as Friedrich Pfaff, Heinrich Wilhelm Dove, Eduard Reusch and Heinrich Baumhauer, not to forget a formal contribution by William Thomson and Peter Guthrie Tait noticed by Theodor Liebisch who informed Mügge about it, and further classifications by Arrien Johnsen, one of Mügge’s pupils. The presentation of this scientific development also mentions the medieval alchemist Pseudo-Geber and the Renaissance metallurgist Vannoccio Biringuccio who ‘heard’ the cry of the tin now known to be due to deformation twinning, the first models of progressive twinning involving some local atomic rearrangement, with Woldemar Voigt in 1898, Yacov Il’ich Frenkel and Tatyana Kontorova in 1938 and the first drawings of a twin(ning) dislocation by Vladimirskii in 1947 and by Charles Frank and Jan van der Merwe two years later.  相似文献   

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