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排序方式: 共有107条查询结果,搜索用时 15 毫秒
21.
Payam Hanafizadeh Mohammad Mehrabioun Kambiz Badie Jahanyar Bamdad Soofi 《Systemic Practice and Action Research》2018,31(4):437-461
Developing innovative business models is one of the complicated issues. Owing to the multiplicity of stakeholders with diverse worldviews about value creation and dynamic markets, the development of innovative business models has turned out to be a complex issue. Therefore, this research seeks to: (1) examine the complicated nature of the development of business model problem and, (2) provide a holistic and systemic framework for the development of business models. The proposed framework employs the Soft Systems Methodology (SSM). This framework is composed of 18 phases, which ranges from the phase of finding out the problem of developing a business model to the phase of its implementation. This methodology is characterized by taking into account the considerations of rational positioning views, evolutionary views, and cognitive views in designing and developing business models. 相似文献
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Benzyl alcohol oxidation by molecular oxygen using solid manganese oxide as a catalyst and n-heptane as the solvent was studied in the liquid phase. The catalyst was synthesized by a simple mechanochemical process at room temperature and was characterized by different physical methods. The catalyst was highly active and 100% selective for benzyl alcohol conversion to benzaldehyde. The solid catalyst can be recovered from the reaction mixture by simple filtration and can be re-used. We found n-heptane to be an excellent solvent for the oxidation reaction, and that the catalyst did not leach into solution. 相似文献
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Javad Safaei-Ghomi 《复旦学报(自然科学版)》2007,(5)
1 Results Sulfonylsemicarbazide derivatives are important compounds as blowing agents in cellular rubber and plastics[1]. Different methods for the preparation of these compounds are reported. For example, sulfonylsemicarbazides are prepared by reaction of sulfinic acid salt with azodicarbonamide in water[2] and reaction of sulfonylchloride with semicarbazide[3-4]. In these methods the yields of products are not high[3-4], the solvent such as pyridine is toxic and also the sulfinic acid salt as starting... 相似文献
26.
Deposition behavior and tribological properties of diamond-like carbon coatings on stainless steels via chemical vapor deposition
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Labani Mustafi M. M. Rahman Mohammad Nur E Alam Al Nasim Mohammad Asaduzzaman Chowdhury M. H. Monir 《矿物冶金与材料学报》2018,25(11):1335-1343
A systematic investigation was carried out to observe the deposition rate of a diamond-like carbon (DLC) coating on two stainless steel substrates by chemical vapor deposition (CVD). The objective of this research is to study the deposition behavior of the DLC coating and its tribological properties in different combinations of methane (CH4) and nitrogen, which were used as precursor gases. The results reveal that the deposition rate increases with increasing CH4 content up to 50vol%. The hardness of the DLC-deposited layer also increases while the friction coefficient decreases with increasing CH4 gas content up to 50% in the precursor gas mixture. 相似文献
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CFH haplotypes without the Y402H coding variant show strong association with susceptibility to age-related macular degeneration 总被引:8,自引:0,他引:8
Li M Atmaca-Sonmez P Othman M Branham KE Khanna R Wade MS Li Y Liang L Zareparsi S Swaroop A Abecasis GR 《Nature genetics》2006,38(9):1049-1054
In developed countries, age-related macular degeneration is a common cause of blindness in the elderly. A common polymorphism, encoding the sequence variation Y402H in complement factor H (CFH), has been strongly associated with disease susceptibility. Here, we examined 84 polymorphisms in and around CFH in 726 affected individuals (including 544 unrelated individuals) and 268 unrelated controls. In this sample, 20 of these polymorphisms showed stronger association with disease susceptibility than the Y402H variant. Further, no single polymorphism could account for the contribution of the CFH locus to disease susceptibility. Instead, multiple polymorphisms defined a set of four common haplotypes (of which two were associated with disease susceptibility and two seemed to be protective) and multiple rare haplotypes (associated with increased susceptibility in aggregate). Our results suggest that there are multiple disease susceptibility alleles in the region and that noncoding CFH variants play a role in disease susceptibility. 相似文献
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Javad Safaei-Ghomi Zohreh Alishahi 《复旦学报(自然科学版)》2005,44(5):789-790
1 Introduction Indazole and its derivatives have little biological significance and have not been found in natural products due to the difficulty for living organisms to construct an N-N bond. Indazole derivatives exhibit variety of pharmacological properties such as anti-inflammatory, antidepressant, antitumor, antiarthritic and analgesic activities~([1]). Different synthetic pathways generate these compounds. For instance, ring closure of pyrazole moiety, addition of hydrazine derivatives t… 相似文献
30.
CuCrW(Al2O3) nanocomposite: mechanical alloying,microstructure, and tribological properties
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The effect of alumina nanoparticle addition on the microstructure and tribological properties of a CuCrW alloy was investigated in this work.Mechanical alloying was carried out in a satellite ball mill.The tribological properties of the samples were evaluated using pin-on-disk wear tests with different pins (alumina,tungsten carbide,and steel pins).The results indicated that the tungsten carbide pin had a lower coefficient of friction than the alumina and steel pins because of its high hardness and low surface roughness.In addition,when the sliding rate was decreased,the weight-loss rate increased.The existence of alumina nanoparticles in the nanocomposite led to a lower weight-loss rate and to a change in the wear mechanism from adhesive to abrasive. 相似文献