首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   45篇
  免费   4篇
工业技术   49篇
  2023年   7篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2019年   3篇
  2018年   3篇
  2017年   2篇
  2016年   6篇
  2015年   2篇
  2014年   3篇
  2013年   2篇
  2012年   2篇
  2011年   3篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   1篇
  2006年   1篇
  2004年   2篇
  1999年   1篇
  1998年   2篇
  1991年   1篇
  1977年   1篇
排序方式: 共有49条查询结果,搜索用时 15 毫秒
21.
This is a case report of corneal hydrops associated with keratoconus with a review of current literature pertaining to diagnosis, histopathology, and treatment options. A 30-year-old African American male presented to the University Eye Institute with acute unilateral pain, redness, and visual impairment. His symptoms, clinical presentation and past diagnosis of keratoconus confirmed his condition to be acute corneal hydrops (CH). The condition was closely followed utilizing topical treatment including hyper-osmotic (Muro 128) and non-steroidal anti-inflammatory agents (Acular and Voltaren). After 4 months, the patient's condition resolved but subsequent corneal scarring resulted. Corneal ectasia in patients with keratoconus may progress into acute rupture of the posterior limiting lamina (PLL) and the endothelium, resulting in CH, which may manifest as an area of edematous and opacified cornea lasting up to 4 months in duration. Acute complications such as CH seldom occur. Histopathology and confocal microscopy can be used to help visualize and understand CH on a cellular level. After regeneration of the corneal structures, central scarring may limit visual acuity and necessitate a corneal transplant.  相似文献   
22.
This article presents a systematic study on creep design of epoxy bonded anchor system. First, a theoretical model for prediction of long-term performance of an anchor system is suggested assuming epoxy layer following Maxwell visco-elastic behavior, which is then validated through an ABAQUS numerical model. A close match between the ABAQUS result and the theoretical model has been reached. Next, a general-purpose methodology for estimating creep capacity of an adhesive bonded anchor system is suggested following AC58 and two creep capacity equations are reached for Model Dry Epoxy and Model Wet Epoxy bonded anchor systems. The derived creep capacity is then used to re-examine the Boston D Tunnel anchor design and a safe design is reached through the suggested method considering the anchor system's long-term creep performance. Last, the ABAQUS model is extended to include the effect of curing temperatures, which shows significant influences of curing temperature on the capacity of an epoxy bonded anchor system.  相似文献   
23.
An unprecedented A‐B‐A type block copolymer electroactive polyurea (EPU) is designed and synthesized with tetraaniline dimer and 1,4‐phenylenediamine via an oxidative coupling, where aniline–nonamer and hexamethylene di‐urea constitute two segments. The EPU was characterized by spectral techniques such as Fourier transform infrared spectroscopy, nuclear magnetic resonance, and UV–vis spectra. The structural characterization of the prepared EPU was obtained by powder X‐ray diffraction and X‐ray photoelectron spectroscopy techniques. EPU reorganizes into core–shell microcapsules in presence of aqueous acetic acid/n‐octane interface. These microcapsules exhibited a wide range of pH responses in their absorption spectrum (UV–vis). The EPU is modified as carbon paste electrode which exhibits a remarkable electrocatalytic oxidation of ascorbic acid (AA, Vitamin C) in 0.2 M and pH 7.0 phosphate buffer solution. The carbon paste electrode is useful in sensing as low as 50 µM of ascorbic acid. This can open up new opportunities for fast, simple detection of AA providing a promising platform for sensor/biosensor designs for AA detection. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46630.  相似文献   
24.
25.
A theoretical outline is sketched to figure out the stream of polyvinyl alcohol (PVA)–based CNTs along a moving surface with multiple slip effects on homogeneous and heterogeneous chemical reactions. The nonlinear radiant, heat, and nonuniform heat source/sink is incorporated in the energy equation to discuss the heat transport phenomenon. The novel theory of non‐Fourier flux model of heat diffusion is also merged in the energy equation. Two kinds of nanoparticles are considered, namely, single wall carbon nanotubes and multiple wall carbon nanotubes, and are suspended in the working PVA to illustrate the flow behavior. Due to a large variety of applications, PVA is used in papermaking, textiles, and a variety of coatings. The principal structure of mathematical model is based upon the system of differential equations, which has been tackled through Runge–Kutta–Fehlberg method in MATLAB software. Graphical images are made vs different physical parameters which emerged in the model. The heat transfer of the fluid enhances with the increase of nonuniform thermal radiation. The homogeneous and heterogeneous chemical reactions slow down the concentration rate.  相似文献   
26.
New class of conducting polyurethanes (CPUs) containing oligoanilines, namely tetraaniline (TAni) or trianiline (TriAni), in the backbone have been synthesized and characterized by formal spectral techniques. The unique properties of these CPUs, viz., electronic conductivity and electrochemical activity arising from the presence of oligoaniline units have been evaluated. The basic polyurethane backbone is derived from toluene diisocyanate, isophorone diisocyanate or hexamethylene diisocyanate, and polypropylene glycols of molecular weight 425 and 2000. In the first category of polyurethanes, the prepolymers obtained from the above reactants were chain terminated by TAni in emeraldine base oxidation state. The conductivity of these CPUs films ranged from 1.2 × 10?5 to 1.77 × 10?3 S cm?1. These polymers showed lower conductivity due to the presence of nonconjugated polyurethane segments. These CPUs exhibited slightly different electrochemical activity than that of TAni. The second category of CPUs is obtained from prepolymers by chain extension with TriAni. The conductivity of these polymers is similar to the TAni analogues but are electrochemically inactive. The anticorrosion properties of two of these polymers have also been evaluated in this study. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40794.  相似文献   
27.
Under ideal conditions, continuous arterial spin labeling (ASL) techniques are higher in SNR than pulsed ASL techniques by a factor of e. Presented here is a direct theoretical and experimental comparison of continuous ASL and pulsed ASL, using versions of both that are amenable to multislice imaging and insensitive to variations in transit times (continuous ASL with a delay before imaging, and QUIPSS II (Quantitative Imaging of Perfusion Using a Single Subtraction-second version)). Perfusion image quality for comparable imaging time was nearly identical for both single-slice and multislice imaging. The measured raw signal was approximately 25% higher with continuous ASL, but the SNR per unit time was identical.  相似文献   
28.
29.
Examination of cottonseed production has shown that boll weevils (Anthonomus grandis), boll rots, and improper handling and storage conditions are critical factors inAspergillus flavus contamination of cotton-seed.A. flavus cultures were isolated from both field-collected and laboratory emerged boll weevils, as well as from boll weevil emergence holes. Diseased cotton bolls have been found to containA. flavus conidia. Infection byA. flavus was limited to the surface of cottonseeds collected from gin and from the gin blower. Seeds improperty stored outside the gin were infected internally withA. flavus. Observation of bright greenish-yellow fluorescence was not useful as a diagnostic procedure to detect contaminated seeds. Aflatoxin-producing potential ofA. flavus isolates is being investigated. WhenA. flavus conidia were artifically inoculated onto the surface of the seeds, 87% of the seeds from Athens, GA, were internally infected whereas only 29% of the seeds from Macon, GA, were internally infected.A. flavus invade the cottonseed embryo through the chalazal region, the micropylar region, or cracks developed in the seed coat during ginning. Invasion of cottonseed byA. flavus was predominant at 28, 30, and 37 C while at 15 and 20 C other fungi dominated in surface and internal invasions of cottonseed. At relative humidities of 75% and 80%,Chaetomium spp. successfully competed in growth on the surface, while at a relative humidity of 90% and above, fungi belonging to the orderMucorales outgrewA. flavus.  相似文献   
30.
Mastitis is an important economic disease causing production losses in dairy industry. Antibiotics are becoming ineffective in controlling mastitis due to the emergence of resistant strains requiring the development of novel therapeutic agents. In this study, the authors present the phytochemical synthesis of silver nanoparticles (AgNPs) with acetyl‐11‐α‐keto‐β‐boswellic acid and evaluation of their activity in Staphylococcus aureus induced murine mastitis. Boswellic acid mediated AgNP (BANS) were oval, polydispersed (99.8 nm) with an minimum inhibitory concentration of 0.033 µg ml−1 against S. aureus, inhibitory concentration (IC50) of 30.04 µg ml−1 on mouse splenocytes and safe at an in vivo acute oral dose of 3.5 mg kg−1 in mice. Mastitis was induced in lactating mice by inoculating S. aureus (log10 5.60 cfu) and treated 6 h post‐inoculation with BANS (0.12 mg kg−1, intramammary and intraperitoneal), and cefepime (1 mg kg−1, intraperitoneal). S. aureus inoculated mice showed increased bacterial load, neutrophil infiltration in mammary glands and elevated C‐reactive protein (CRP) in serum. Oxidative stress was also observed with elevated malondialdehyde level, superoxide dismutase (SOD) and catalase (CAT) activities. BANS treatment significantly (P  < 0.05) reduced bacterial load, CRP, SOD, CAT activities and neutrophil infiltration in affected mammary glands. BANS could be a potential therapeutic agent for managing bovine mastitis.Inspec keywords: nanomedicine, nanoparticles, silver, antibacterial activity, drugs, diseases, enzymesOther keywords: antibacterial effects, antiinflammatory effects, antioxidant effects, acetyl‐11‐α‐keto‐β‐boswellic acid, mediated silver nanoparticles, experimental murine mastitis, economic disease, dairy industry, resistant strains, phytochemical synthesis, Staphylococcus aureus, minimum inhibitory concentration, inoculating S. aureus, neutrophil infiltration, mammary glands, elevated C‐reactive protein, superoxide dismutase, catalase, bovine mastitis, Ag  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号