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排序方式: 共有229条查询结果,搜索用时 15 毫秒
101.
102.
C. N. R. Rao Prof. Dr. A. K. Sood Prof. Dr. K. S. Subrahmanyam A. Govindaraj Dr. 《Angewandte Chemie (International ed. in English)》2009,48(42):7752-7777
Every few years, a new material with unique properties emerges and fascinates the scientific community, typical recent examples being high‐temperature superconductors and carbon nanotubes. Graphene is the latest sensation with unusual properties, such as half‐integer quantum Hall effect and ballistic electron transport. This two‐dimensional material which is the parent of all graphitic carbon forms is strictly expected to comprise a single layer, but there is considerable interest in investigating two‐layer and few‐layer graphenes as well. Synthesis and characterization of graphenes pose challenges, but there has been considerable progress in the last year or so. Herein, we present the status of graphene research which includes aspects related to synthesis, characterization, structure, and properties. 相似文献
103.
Kim JH Yeo WH Shu Z Soelberg SD Inoue S Kalyanasundaram D Ludwig J Furlong CE Riley JJ Weigel KM Cangelosi GA Oh K Lee KH Gao D Chung JH 《Lab on a chip》2012,12(8):1437-1440
A rapid, accurate tuberculosis diagnostic tool that is compatible with the needs of tuberculosis-endemic settings is a long-sought goal. An immunofluorescence microtip sensor is described that detects Mycobacterium tuberculosis complex cells in sputum in 25 minutes. Concentration mechanisms based on flow circulation and electric field are combined at different scales to concentrate target bacteria in 1 mL samples onto the surfaces of microscale tips. Specificity is conferred by genus-specific antibodies on the microtip surface. Immunofluorescence is then used to detect the captured cells on the microtip. The detection limit in sputum is 200 CFU mL(-1) with a success rate of 96%, which is comparable to PCR. 相似文献
104.
We present new experimental data on thick target bremsstrahlung spectra generated from the interaction of energetic electrons
with bulk matter. The ‘photon yields’ in terms of double differential cross-sections (DDCS) are measured for pure elements
of thick targets: Ti (Z = 22), Ag (Z = 47), W (Z = 74) and Pt (Z = 78) under the impact of 10 keV electrons. Comparison of DDCS obtained from the experimental data is made with those predicted
by Monte-Carlo (MC) calculations using PENELOPE code. A close agreement between the experimental data and the MC calculations
is found for all the four targets within the experimental error of 16%. Furthermore, the ratios of DDCS of bremsstrahlung
photons emitted from Ag, W and Pt with those from Ti as a function of photon energy are examined with a relatively lower uncertainty
of about 10% and they are compared with MC calculations. A satisfactory agreement is found between the experiment and the
calculations within some normalizing factors. The variations of DDCS as a function of Z and of photon energy are also studied which show that the DDCS vary closely with Z; however, some deviations are observed for ‘tip’ photons emitted from high Z targets. 相似文献
105.
An extractive atomic-absorption spectrophotometric (AAS) procedure is developed for fast and accurate determination of up to 20 mug/g antimony in lead and zinc concentrates and other smelter products. The procedure involves digestion of the sample with potassium bisulphate and sulphuric acid, addition of hydrazine to reduce all antimony to Sb(III), reoxidation to Sb(V), extraction of the chloro-complex of antimony(V) with n-butyl acetate, and AAS analysis of the organic phase for antimony. 相似文献
106.
M. B. Subrahmanyam 《Journal of Optimization Theory and Applications》1989,62(2):311-319
The simplex algorithm of Nelder and Mead is extended to handle nonlinear optimization problems with constraints. To prevent the simplex from collapsing into a subspace near the constraints, a delayed reflection is introduced for those points moving into the infeasible region. Numerical experience indicates that the proposed algorithm yields good results in the presence of both inequality and equality constraints, even when the constraint region is narrow. We note that it may be possible to modify and improve the algorithm by trying out variants. 相似文献
107.
Gantumur Battogtokh Oyuntuya Gotov Nithya Subrahmanyam Young Tag Ko Hamidreza Ghandehari 《Macromolecular bioscience》2019,19(7)
Photodynamic therapy (PDT) is a promising cancer treatment approach. However, the photosensitizers (PS) used for PDT are often limited by their poor solubility and selectivity for tumors. The goal of this study is to improve water solubility and delivery of the photosensitizer 2‐[1‐hexyloxyethyl]‐2‐divinyl pyropheophorbide‐a (HPPH) to breast cancer cells. An N‐(2‐hydroxypropyl)methacrylamide (HPMA) copolymer–HPPH photosensitizer conjugate is synthesized with heat shock receptor glucose‐regulated protein 78 (GRP78), targeting to GRP78 receptors of MCF‐7 cells, which are upregulated under mild hyperthermia. It is found that the uptake of the GRP78 targeted pep‐HPMA‐HPPH copolymer conjugate in MCF‐7 cells is improved through heat induction. Under mild hyperthermia the targeted copolymers are more effective compared to free HPPH. These results show potential for the utility of mild hyperthermia and copolymer delivery vehicles to enhance the efficacy of photodynamic therapy. 相似文献
108.
109.
A versatile and useful preparation of 4-pyridine carboxaldehyde, an important pharmaceutical intermediate, by vapour phase mode of oxidation of 4-pyridinemethanol over V-Mo-O catalyst is developed for the first time. The probable mechanism and experimental procedure are reported. 相似文献
110.
Lakshmi Narayana Chennuru Thirupathi Choppari Subrahmanyam Duvvuri Pramod Kumar Dubey 《Journal of separation science》2013,36(18):3004-3010
The enantioselectivity of proton pump inhibitors, namely, omeprazole, lansoprazole, rabeprazole, pantoprazole, tenatoprazole, and ilaprazole were studied using new generation chiral packing materials: CHIRALPAK IA, CHIRALPAK IB, and CHIRALPAK IC. Two versatile techniques, HPLC and supercritical fluid chromatography (SFC) were used in this study. CHIRALPAK IC has shown superior selectivity under both LC and SFC conditions, whereas CHIRALPAK IA has shown good selectivity in SFC when compared to LC under primary screening conditions. The chiral recognition ability in LC and SFC modes were found to be in the order CHIRALPAK IC > CHIRALPAK IA > CHIRALPAK IB. In addition to diode array detection, chiral detection was carried out using a laser polarimeter and the elution orders were found to be the same in both LC and SFC elution modes. Mobile phase modifiers and column temperature effects were also studied. In SFC, modifiers (cosolvent) elution strength was found to be in the order ethanol > methanol > 2‐propanol > acetonitrile. In both LC and SFC, a decrease in retention and increase in resolution with an increase in temperature was noticed for all the proton pump inhibitors. 相似文献