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排序方式: 共有427条查询结果,搜索用时 156 毫秒
21.
22.
Laurence Feldmeyer Kristine Heidemeyer Nikhil Yawalkar 《International journal of molecular sciences》2016,17(8)
Acute generalized exanthematous pustulosis (AGEP) is a severe, usually drug-related reaction, characterized by an acute onset of mainly small non-follicular pustules on an erythematous base and spontaneous resolution usually within two weeks. Systemic involvement occurs in about 20% of cases. The course is mostly benign, and only in rare cases complications lead to life-threatening situations. Recent studies highlight the importance of genetic variations in interleukin-36 receptor antagonist gene (IL-36RN) in the pathogenesis of this disease. The physiopathology of AGEP remains unclear, but an involvement of innate and acquired immune cells together with resident cells (keratinocytes), which recruit and activate neutrophils via production of cytokines/chemokines such as IL-17, IL-36, granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor alpha (TNFα) and chemokine (C-X-C motif) ligand 8 (CXCL8)/IL-8, has been postulated. Treatment is based on the removal of the causative drug, supportive care, infection prevention and use of potent topical or systemic steroids. 相似文献
23.
Applications of Polymer Matrix Syntactic Foams 总被引:1,自引:0,他引:1
Nikhil Gupta Steven E. Zeltmann Vasanth Chakravarthy Shunmugasamy Dinesh Pinisetty 《JOM Journal of the Minerals, Metals and Materials Society》2014,66(2):245-254
A collection of applications of polymer matrix syntactic foams is presented in this article. Syntactic foams are lightweight porous composites that found their early applications in marine structures due to their naturally buoyant behavior and low moisture absorption. Their light weight has been beneficial in weight sensitive aerospace structures. Syntactic foams have pushed the performance boundaries for composites and have enabled the development of vehicles for traveling to the deepest parts of the ocean and to other planets. The high volume fraction of porosity in syntactic foams also enabled their applications in thermal insulation of pipelines in oil and gas industry. The possibility of tailoring the mechanical and thermal properties of syntactic foams through a combination of material selection, hollow particle volume fraction, and hollow particle wall thickness has helped in rapidly growing these applications. The low coefficient of thermal expansion and dimensional stability at high temperatures are now leading their use in electronic packaging, composite tooling, and thermoforming plug assists. Methods have been developed to tailor the mechanical and thermal properties of syntactic foams independent of each other over a wide range, which is a significant advantage over other traditional particulate and fibrous composites. 相似文献
24.
This investigation reports the preparation of styrene–α‐olefinic random copolymers, using 1‐octene as an α‐olefin, via atom transfer radical polymerization. Atom transfer radical copolymerization of styrene with 1‐octene was successfully carried out using phenylethyl bromide as initiator and CuBr as catalyst in combination with N, N, N′, N″, N″‐pentamethyldiethylenetriamine as ligand. The copolymers had controlled molecular weight, narrow dispersity and well‐defined end groups with significant 1‐octene incorporation in the polymer. Incorporation of 1‐octene in the copolymers was confirmed using 1H NMR and matrix‐assisted laser desorption ionization time‐of‐flight mass spectroscopy. An increase in 1‐octene content in the monomer feed led to an increase in the level of incorporation of the α‐olefin in the copolymer. An increase in the concentration of 1‐octene led to a decrease in the rate of polymerization and an increase in dispersity. The glass transition temperature of the copolymer gradually decreased as the incorporation of 1‐octene increased. Copyright © 2011 Society of Chemical Industry 相似文献
25.
26.
Shajan Nikhil Arora Kanwer Singh Asati Brajesh Sharma Vikram Shome Mahadev 《Metallurgical and Materials Transactions A》2018,49(4):1276-1286
Metallurgical and Materials Transactions A - Effect of post-weld heat treatment on the weld microstructure, texture, and its correlation to the toughness of flash butt welded joints were... 相似文献
27.
Kumar Nikhil Verma A. K. Sardana Sahil Sarkar K. Singh T. N. 《Bulletin of Engineering Geology and the Environment》2018,77(2):595-608
Bulletin of Engineering Geology and the Environment - Landslides that occur due to the rapid motion of a rock-mass are a primary risk in mountainous terrains and are a danger to human life and... 相似文献
28.
Durga Prasad Muni Nikhil R Pal Jyotirmoy Das 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2006,36(1):106-117
This paper presents an online feature selection algorithm using genetic programming (GP). The proposed GP methodology simultaneously selects a good subset of features and constructs a classifier using the selected features. For a c-class problem, it provides a classifier having c trees. In this context, we introduce two new crossover operations to suit the feature selection process. As a byproduct, our algorithm produces a feature ranking scheme. We tested our method on several data sets having dimensions varying from 4 to 7129. We compared the performance of our method with results available in the literature and found that the proposed method produces consistently good results. To demonstrate the robustness of the scheme, we studied its effectiveness on data sets with known (synthetically added) redundant/bad features. 相似文献
29.
Naren Noolu Nikhil Murdeshwar Kevin Ely John Lippold William BaeslackIII 《Journal of Electronic Materials》2004,33(4):340-352
Gold-aluminum ball bonds were thermally exposed at constant elevated temperatures, and the resultant phase transformations
studied in detail. The as-bonded microstructure of a Au-Al ball bond essentially consisted of a reaction zone (termed “alloyed
zone” (AZ) in the as-bonded condition) between the Au bump and the bonded Al metallization. It is the growth of the reaction
zone between the Au bump and the bonded Al metallization and also the nonbonded Al metallization during thermal exposure that
gave rise to the various phase transformations. Au4Al, Au8Al3, and Au2Al are the predominant phases that grew across the ball bond until the bonded Al metallization is available to take part in
the interdiffusion reactions. After the complete consumption of the bonded Al metallization, the Au-Al phases reverse transformed
resulting in the formation of the Au4Al phase in the entire reaction zone across the ball bond (RZ-A). The lateral interdiffusion reactions resulted in the nucleation
and the growth of all of the Au-Al phases given by the phase diagram. Kidson’s analysis and Tu et al.’s treatment were extended
to a five-phase binary system to explain the phase transformations in thermally exposed Au-Al ball bonds. It is possible for
all of the Au-Al phases to grow across a ball bond uninhibited as long as the bonded metallization is available. However,
the supply limitation of the bonded metallization gives rise to reverse transformations where Al-rich phases transform to
Au-rich phases and eventually result in the formation of the Au4Al phase in the entire RZ-A. If infinite time is allowed, Au4Al would dissolve; the extent of which is dependent on the solubility of Al in Au. No supply of Au lateral to the bond causes
the reverse transformation of the Au4Al phase, giving rise to the lateral growth of the remaining Au-Al phases. If infinite time is allowed, the lateral phase
transformations would result in the formation of a phase that is dependant on the relative proportion of Au and Al present
in the nonbonded metallization (NBM) and Au4Al below the void line. Hence, the presence of a phase in a particular location of a ball bond is dependent on the time and
temperature of thermal exposure. 相似文献
30.
Beaucage G Kammler HK Mueller R Strobel R Agashe N Pratsinis SE Narayanan T 《Nature materials》2004,3(6):370-374
Flame synthesis is one of the most versatile and promising technologies for large-scale production of nanoscale materials. Pyrolysis has recently been shown to be a useful route for the production of single-walled nanotubes, quantum dots and a wide variety of nanostructured ceramic oxides for catalysis and electrochemical applications. An understanding of the mechanisms of nanostructural growth in flames has been hampered by a lack of direct observations of particle growth, owing to high temperatures (2,000 K), rapid kinetics (submillisecond scale), dilute growth conditions (10(-6) volume fraction) and optical emission of synthetic flames. Here we report the first successful in situ study of nanoparticle growth in a flame using synchrotron X-ray scattering. The results indicate that simple growth models, first derived for colloidal synthesis, can be used to facilitate our understanding of flame synthesis. Further, the results indicate the feasibility of studies of nanometre-scale aerosols of toxicological and environmental concern. 相似文献