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排序方式: 共有194条查询结果,搜索用时 15 毫秒
1.
Takamichi Iida Roderick Guthrie Nagendra Tripathi 《Metallurgical and Materials Transactions B》2006,37(4):559-564
By combining the modified Stokes-Einstein formula with the authors’ model for the melting-point viscosity, the authors present
a model for accurate predictions of self-diffusivity of liquid metallic elements. The model is expressed in terms of well-known
physical quantities and has been applied to various liquid metallic elements for which experimental data are available. The
results of calculations show that agreement with experimental data is excellent; the uncertainties in the calculations of
the self-diffusivities in various liquid metallic elements are equal to the uncertainties associated with experimental measurements.
Also, the authors propose an expression for the temperature dependence of self-diffusivity in liquid metallic elements in
terms of melting-point temperature. Using the model, self-diffusivity data are predicted for liquid iron, cobalt, nickel,
titanium, aluminum, magnesium, silicon, and so forth. 相似文献
2.
Silicon - In this paper, a dielectric modulated dual material gate TFET (DM-DMG_TFET)based biosensor is proposed. In order to detect various biomolecules, a nanogap cavity is formed by the... 相似文献
3.
Resolving Deep Sub-Wavelength Scattering of Nanoscale Sidewalls Using Parametric Microscopy 下载免费PDF全文
Nagendra Parasad Yadav Ji-Chuan Xiong Wei-Ping Liu Wei-Ze Wang Yun Cao Ashish Kumar Xue-Feng Liu 《电子科技学刊:英文版》2021,19(3):233-242
The quantitative optical measurement of deep sub-wavelength features with sub-nanometer sensitivity addresses the measurement challenge in the semiconductor fabrication process. Optical scatterings from the sidewalls of patterned devices reveal abundant structural and material information. We demonstrated a parametric indirect microscopic imaging (PIMI) technique that enables recovery of the profile of wavelength-scale objects with deep sub-wavelength resolution, based on measuring and filtering the variations of far-field scattering intensities when the illumination was modulated. The finite-difference time-domain (FDTD) numerical simulation was performed, and the experimental results were compared with atomic force microscopic (AFM) images to verify the resolution improvement achieved with PIMI. This work may provide a new approach to exploring the detailed structure and material properties of sidewalls and edges in semiconductor-patterned devices with enhanced contrast and resolution, compared with using the conventional optical microscopy, while retaining its advantage of a wide field of view and relatively low cost. 相似文献
4.
Jagadeesh Nagendra Manda Milica Markovic Prof. Ellen M. Zimmermann Prof. Shimon Ben-Shabat Prof. Arik Dahan Prof. Aaron Aponick 《ChemMedChem》2020,15(17):1639-1644
Novel phospholipid (PL)-cyclosporine conjugates were prepared and studied as potential prodrugs for inflammatory bowel disease (IBD). Our approach relies on phospholipase A2 (PLA2), which is overexpressed in the inflamed intestinal tissues, as the prodrug activator to potentially release cyclosporine at the site of inflammation. PL-cyclosporine prodrug conjugates with methylene linkers of various lengths between the sn-2 position of the PL and cyclosporine were synthesized and evaluated for in vitro activation. Surprisingly, despite previous work indicating that conjugates with six methylene linkers between the lipid and drug would suffer rapid enzymatic hydrolysis, with cyclosporine this was not observed. However, compounds with longer linkers (n=10, 12 methylene units) display complete release of the drug by PLA2-catalyzed hydrolysis, thus demonstrating the importance and profound impact of structural fine-tuning. This study represents a proof-of-concept for our hypothesis and a first step towards a truly targeted IBD treatment with cyclosporine that could be administered throughout the GI tract. 相似文献
5.
6.
ATP-regulation of antioxidant properties and phenolics in litchi fruit during browning and pathogen infection process 总被引:3,自引:0,他引:3
Chun Yi Yueming Jiang John Shi Hongxia Qu Sophia Xue Xuewu Duan Jingyu Shi Nagendra K. Prasad 《Food chemistry》2010
The impact of energy level on antioxidant properties in relation to pericarp browning and loss of disease resistance of litchi fruit was investigated. Litchi fruits were vacuum-infiltrated with distiled water (control), 1 mM adenosine triphosphate (ATP) and 0.5 mM 2,4-dinitrophenol (DNP) under 75 kPa for 3 min before being inoculated with Peronophythora litchi or not. ATP-treated fruits presented higher activities of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX). Higher activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, reducing power and contents of phenolic compounds were also observed in ATP-treated fruit during storage. In contrast, DNP treatment lowered the enzymes activities, scavenging ability and the contents of phenolic compounds. Higher levels of antioxidant enzymatic system and non-enzymatic system were observed in P. litchii-inoculated fruits than those in non-inoculated fruits. Application of ATP and DNP exhibited a similar change patterns and effects in inoculated fruits. When related to previously reported ATP levels, the results suggested that ATP levels could regulate the antioxidant system. Sufficient available energy is crucial for inhibiting browning and preventing the loss of disease resistance in harvested litchi fruit. 相似文献
7.
Pradeep Bhartiya Neha Kaushik Linh N. Nguyen Sander Bekeschus Kai Masur Klaus-Dieter Weltmann Nagendra Kumar Kaushik Eun Ha Choi 《International journal of molecular sciences》2022,23(6)
Excess amounts of redox stress and failure to regulate homeostatic levels of reactive species are associated with several skin pathophysiologic conditions. Nonmalignant cells are assumed to cope better with higher reactive oxygen and nitrogen species (RONS) levels. However, the effect of periodic stress on this balance has not been investigated in fibroblasts in the field of plasma medicine. In this study, we aimed to investigate intrinsic changes with respect to cellular proliferation, cell cycle, and ability to neutralize the redox stress inside fibroblast cells following periodic redox stress in vitro. Soft jet plasma with air as feeding gas was used to generate plasma-activated medium (PAM) for inducing redox stress conditions. We assessed cellular viability, energetics, and cell cycle machinery under oxidative stress conditions at weeks 3, 6, 9, and 12. Fibroblasts retained their usual physiological properties until 6 weeks. Fibroblasts failed to overcome the redox stress induced by periodic PAM exposure after 6 weeks, indicating its threshold potential. Periodic stress above the threshold level led to alterations in fibroblast cellular processes. These include consistent increases in apoptosis, while RONS accumulation and cell cycle arrest were observed at the final stages. Currently, the use of NTP in clinical settings is limited due to a lack of knowledge about fibroblasts’ behavior in wound healing, scar formation, and other fibrotic disorders. Understanding fibroblasts’ physiology could help to utilize nonthermal plasma in redox-related skin diseases. Furthermore, these results provide new information about the threshold capacity of fibroblasts and an insight into the adaptation mechanism against periodic oxidative stress conditions in fibroblasts. 相似文献
8.
S. Nagendra J.B. Staubach A.J. Suydam S.J. Ghunakikar V.R. Akula 《Structural and Multidisciplinary Optimization》2005,29(3):213-231
The role of uncertainty in information rich design systems is critical to the development of advanced propulsion systems. Future turbine engines would have lower lifetime operating costs similar to current evolving automotive systems. Detailed multi-physics models (thermo-fluid, structural and mechanical systems) and an operational environment are enablers of rapid correction and model-based predictive analyses. Bayesian machine learning paradigms are developed to identify the behavior of turbo-machinery components for preliminary design. The embedded models approach enables systematic evolution from individual components level to the advanced engine. The embedded models approach enables systematic evolution from individual components level to the advanced engine. A rapid response strategy is proposed, for design of turbine disks by using multidisciplinary optimization and neural networks. iSIGHT optimization software is interfaced with ANSYS to find optimum designs for a given set of design boundary conditions (rpm, live rim load, thermals, etc.). The optimum designs obtained from iSIGHT for different set of design conditions are used for machine learning and design knowledge recognition using the neural network technique. The trained network is used to predict responses for design boundary conditions. Responses predicted by the neural network are validated using ANSYS. Discrete design points are chosen from the wide design space of turbine disks. A hierarchical neural network approach provides an ability to quickly train the network and predict responses (weight, stresses, burst margin, etc.) for applied design conditions. This basic building process involves four steps starting from identifying design boundary conditions to the prediction of design shape for the disk. Sensitivity-based scaling rules are developed, to accommodate different materials for the disk. The technique is developed in RAPIDDISK, which provides an optimal preliminary shape and design attributes for a turbine disk. 相似文献
9.
Chetana Nagendra Robert Michael Owens Mary Jane Irwin 《The Journal of VLSI Signal Processing》1995,9(3):193-209
In this paper, we present a novel scheme for performing fixed-point arithmetic efficiently on fine-grain, massively parallel,
programmable architectures including both custom and FPGA-based systems. We achieve anO(n) speedup, wheren is the operand precision, over the bit-serial methods of existing fine-grain systems such as the DAP, the MPP and the CM2,
within the constraints of regular, near neighbor communication and only a small amount of on-chip memory. This is possible
by means of digit pipelined algorithms which avoid broadcast and which operate in a fully systolic manner by pipelining at
the digit level. A base 4, signed-digit, fully redundant number system and on-line techniques are used to limit carry propagation
and minimize communication costs. p ]Although our algorithms are digit-serial, we are able to match the performance of the
bit-parallel methods, while retaining low communication complexity. Reconfigurable hardware systems built using field programmable
gate arrays (FPGA's) can share in the speed benefits of these algorithms. By using the organization of logic blocks suggested
in this paper, problems of placement and routing that exist in such systems can be avoided. Since the algorithms are amenable
to pipelining, very high throughput can be obtained. 相似文献
10.
A new method for the determination of the optical constants of absorbing films supported on a transparent substrate using measured normal incidence R/T and R/T values is presented. Compared to the classical normal incidence photometric methods of deducing the optical constants from the measured R and T values the present method offers a time saving of 50% in experimental measurements and is able to give the optical constants and thickness of the films simultaneously to an accuracy of 2% and 0.5% respectively. 相似文献