排序方式: 共有70条查询结果,搜索用时 15 毫秒
41.
An all-optical adder/subtractor (A/S) unit with the (TOAD) is proposed. The all-optical A/S unit with help of terahertz optical asymmetric demultiplexer a set of all-optical full-adders and optical exclusive- ORs (XORs), can be used to perform a fast central processor unit using optical hardware components. We try to exploit the advantages of TOAD-based optical switch to design an integrated all-optical circuit which can perform binary addition and subtraction. With computer simulation results confirming the described methods, conclusions are given. 相似文献
42.
Using particle simulations of the uniform shear flow of a rough dilute granular gas, we show that the translational and rotational velocities are strongly correlated in direction, but there is no orientational correlation-induced singularity at perfectly smooth (beta=-1) and rough (beta=1) limits for elastic collisions (e=1); both the translational and rotational velocity distribution functions remain close to a Gaussian for these two limiting cases. Away from these two limits, the orientational as well as spatial velocity correlations are responsible for the emergence of non-Gaussian high-velocity tails. The tails of both distribution functions follow stretched exponentials, with the exponents depending on normal (e) and tangential (beta) restitution coefficients. 相似文献
43.
Keshab Ch Ghosh Indranil Duttagupta Chandra Bose Priyanjalee Banerjee Anuran Kumar Gayen 《合成通讯》2019,49(2):221-236
A solution phase method was adopted for the synthesis of proline-containing cyclic pentapeptide 2 and total synthesis of naturally occurring cyclic heptapeptide Reniochalistatin B 3. For the synthesis of 3, both divergent and convergent strategies were used to improve the overall yield from 12 to 25%. Different N and C terminal modified linear analogs and congeners of 2 and 3 were synthesized. Both cyclic peptides 2 and 3 and their linear analogs/congeners were evaluated for anti-cancer activity against HeLa cell line, among which pentapeptide 2?h and hexapeptide 3n with N-terminal protected hexafluoroisopropyl carbamates (HFIPC) interestingly showed higher cytotoxicity with an IC50 of 2.73 and 4.3?µM, respectively compared to their Boc-protected analogs 2a (IC50 20?µM) and 3c (IC50 38.51?µM) and cyclic peptides 2 (>100?µM) and 3 (47?µM). These results were further validated by biological experiments such as colony formation and wound healing assays. 相似文献
44.
45.
Sengupta T Gayen KS Pandit P Maiti DK 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(7):1905-1909
The first ever breakthrough toward activation of β-ketoacetanilide and subsequent C-C and C-N bond-forming intermolecular-cascade cyclization processes is demonstrated by development of the unprecedented Lewis acid property of non-toxic FeCl(3)?6H(2)O. Aromatic, aliphatic, α,β-unsaturated, chiral sugar-based and chromone aldehydes were regio- and stereoselectively cyclized with acetoacetanilides toward construction of valuable N-containing highly functionalized 2-pyridones (see scheme for an example). 相似文献
46.
Ruma Roy Choudhury Chirantan Roy Choudhury Stuart R. Batten Samiran Mitra 《Structural chemistry》2008,19(4):645-649
One new one-dimensional polymeric complex [Cd(C5H6N2)2(SeCN)2]
n
(1) has been synthesized and characterized by elemental analyses, spectroscopic studies and single crystal X-ray crystallography.
Crystal structure shows the one-dimensional chain is propagated through doubly bridging selenocyanate and 4-aminopyridine
acts as terminal ligand. The complex was characterized by fluorescence and NMR spectral studies and the results are consistent
with the crystal structure. 相似文献
47.
Paramita Gayen Somnath Jan Dr. Nilkanta Chowdhury Dr. Snehasish Ghosh Monjuri Hembram Dr. Angshuman Bagchi Dr. Rituparna Sinha Roy 《化学:亚洲杂志》2021,16(24):4018-4036
Developing non-immunogenic therapeutic biomolecules for facilitating blood clotting followed by wound healing via therapeutic angiogenesis, still remains a formidable challenge. Excessive blood loss of accident victims and battalions cause a huge number of deaths worldwide. Patients with inherited bleeding disorders face acute complications during injury and post-surgery. Biologically-inspired peptide-based hemostat can act as a potential therapeutic for handling coagulopathy. Additionally, non-healing wounds for patients having ischemic diseases can cause severe clinical complications. Advancement in stabilized growth-factor-based proangiogenic therapy may offer effective possibilities for the treatment of ischemic pathology. This review will discuss nature-inspired biocompatible stabilized peptide- and protein-based molecular medicines to serve unmet medical challenges for handling traumatic coagulopathy and impaired wound healing. 相似文献
48.
Vertically aligned ZnO nanorod arrays with different aspect ratios were synthesized by hybrid wet chemical route. Modulation of the field emission properties (FE) with aspect ratio of ZnO nanorods was examined. With the increase in the aspect ratio, the emission current density increases from 0.02 to 8 μA/cm2 at 7.0 V/μm. Turn-on voltage was seen to decrease from 9.6 to 7 V/μm at a current density of 10 μA/cm2 with the increase in aspect ratio in the ZnO films. The interrelation between the FE characteristics (emission thresholds, current density, surface uniformity, etc.) and microstructure of the ZnO nanostructure obtained from scanning electron microscopy (SEM) and atomic force microscopy (AFM) was discussed. Quality of the ZnO nanorods was also examined by using Raman spectroscopy and Fourier transformed infrared spectroscopy (FTIR). It was found that the observed enhancements of FE characteristics could mainly be attributed to the increase in aspect ratio and associated number density of ZnO nanorods. 相似文献
49.
N. Valappil M. Luberto V.M. Menon I. Zeylikovich T.K. Gayen J. Franco B.B. Das R.R. Alfano 《Photonics and Nanostructures》2007,5(4):184-188
The authors report the fabrication of a one-dimensional microcavity structure embedded with colloidal CdSe/ZnS core/shell quantum dots using solution processing. The microcavity structures were fabricated by spin coating alternating layers of polymers of different refractive indices (poly-vinylcarbazole—PVK, and poly-acrylic acid—PAA) to form the distributed Bragg reflectors (DBRs). Greater than 90% reflectivity was obtained using ten periods of the structure. The one-dimensional microcavity was formed by sandwiching a λ/n thick defect layer between two such DBRs. The emission of the quantum dots from the microcavity structure demonstrated directionality following the cavity mode dispersion and spectral narrowing. Room temperature time-resolved photoluminescence measurements carried out on this structure showed significant reduction in the photoluminescence decay time which is attributed primarily to nonradiative mechanism originating in the presence of the PVK host matrix. The photoluminescence decay time of the quantum dots was found to be 1000 ps while for the quantum dots embedded in the polymer host and the microcavity were 400 and 150 ps, respectively. 相似文献
50.
The interaction of flexural‐gravity waves with a thin circular‐arc‐shaped permeable plate submerged beneath the ice‐covered surface of water with uniform finite depth is considered under the assumption of linear theory. The problem is reduced to a second kind hypersingular integral equation for the potential difference across the plate which is solved approximately by an expansion–collocation method. Utilizing the solution, the reflection and the transmission coefficients and the hydrodynamic forces are evaluated numerically. The focus of the paper is to illustrate the effect of a porous curved plate submerged in finite depth water with an ice‐cover on the normally incident waves. Numerical results for a circular‐arc‐shaped plate for different configurations are derived and represented graphically. Also, by choosing an appropriate set of parameters, the known results for a circular‐arc‐shaped rigid plate submerged in deep water and a semicircular porous plate submerged in finite depth water with a free surface are recovered as special cases. 相似文献