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排序方式: 共有752条查询结果,搜索用时 15 毫秒
61.
Nanda Gopal Sahoo Yong Chae Jung Jae Whan Cho 《Materials and Manufacturing Processes》2007,22(4):419-423
We report the electroactive shape memory composites obtained by shape memory polyurethane block copolymer (PU) and multi-walled carbon nanotubes (MWNTs), and polypyrrole (PPy). An addition of combined MWNTs and PPy contributed to an enhancement in conductivity of PU-MWNTs composites. PU containing 2.5% MWNTs showed better mechanical and thermal properties than other composites, but conductivity was not sufficient for showing the shape memory effect by applying electrical voltages. However, when the composite was lightly coated by PPy (2.5%), its conductivity was the highest than other composites. Such the conductivity of this composite was enough to show electroactive shape recovery by heating above transition temperature of 40-48°C due to melting of polycaprolactone soft segment domain. The good shape recovery of 90-96% could be obtained in the shape recovery test when an electric field of 25 V was applied. 相似文献
62.
Swapan K. Bhattacharya Mahesh G. Varadarajan Premjeet Chahal Gopal C. Jha Rao R. Tummala 《Journal of Electronic Materials》2007,36(3):242-244
To realize embedded resistors on multilayer benzocyclobutene (BCB) either on-chip or on-board, a low-cost large format electroless
process for deposition of NiP and NiWP thin-film resistors using both low-temperature (25°C) and high-temperature (90°C) baths
has been developed. The electroless process exhibits uniform resistor thickness in the submicron range and offers low profile
and excellent adhesion to the BCB dielectric layer. The resistor films also act as a seed layer for direct electroplating
of copper traces. The NiP alloys can also be tailored to a variable temperature coefficient of resistance (TCR) with different
alloy compositions. The electroless process can be adopted in the PCB manufacturing industries with no additional investment.
This article is the first report on electroless plated thin film resistors on low loss BCB dielectric. 相似文献
63.
Thermoluminescence (TL) characteristics of NaYF4 crystals doped with Sm3+ have been studied after γ-ray irradiation. Dependence of luminescence efficiency on Sm3+ concentration and radiation dose has been measured and possible applications of NaYF4: Sm3+ as a novel phosphor for TL dosimetry have been investigated. The efficiency of 0·3 mole% Sm3+ doped NaYF4 crystal has been found to be maximum and comparable with commercial thermoluminescence dosimetric (TLD) materials. 相似文献
64.
Judy Gopal Manikandan Muthu Se-Chul Chun Hui-Fen Wu 《Proteomics. Clinical applications》2015,9(5-6):469-481
Urine proteomics has become a subject of interest, since it has led to a number of breakthroughs in disease diagnostics. Urine contains information not only from the kidney and the urinary tract but also from other organs, thus urinary proteome analysis allows for identification of biomarkers for both urogenital and systemic diseases. The following review gives a brief overview of the analytical techniques that have been in practice for urinary proteomics. MALDI-MS technique and its current application status in this area of clinical research have been discussed. The review comments on the challenges facing the conventional MALDI-MS technique and the upgradation of this technique with the introduction of nanotechnology. This review projects nano-based techniques such as nano-MALDI-MS, surface-assisted laser desorption/ionization, and nanostructure-initiator MS as the platforms that have the potential in trafficking MALDI-MS from the lab to the bedside. 相似文献
65.
The continuous increase of heavy metal ions in the environment is imposing serious problems in agricultural yield and increases human health threats through accumulation in the food chain. Various studies have shown that heavy metals influence the metabolic processes and pigment concentrations in leaves, and thus affect the laser induced fluorescence (LIF) spectra. Leaf level in vivo LIF spectra using the 488 nm and 355 nm laser lines, fluorescence induction kinetics (FIK) using the 488 nm laser line, and photosynthetic pigments of the control and nickel treated wheat seedlings were measured. The peak parameters of the blue and UV‐excited spectral bands were calculated by Gaussian curve fitting. The FIK measured at both the chlorophyll (Chl) fluorescence bands was used to evaluate the fluorescence decrease ratio (R Fd). The variations in R Fd and fluorescence ratios of intensities, bandwidth and band area, with varying concentrations of nickel, were revealed as promising parameters in determining the health status of wheat seedlings. These leaf level findings can be extended at canopy level in the field using laser based light detection and ranging (LIDAR) systems. 相似文献
66.
An understanding of human factors and ergonomics facilitates the design of artefacts, tasks and environments that fulfil their users’ physical and cognitive requirements. Research in these fields furthers the goal of efficiently accommodating the desired percentage of user populations through enhanced awareness and modelling of human variability. Design for sustainability (DfS) allows for these concepts to be leveraged in the broader context of designing to minimise negative impacts on the environment. This paper focuses on anthropometry and proposes three ways in which its consideration is relevant to DfS: reducing raw material consumption, increasing usage lifetimes and ethical human resource considerations. This is demonstrated through the application of anthropometry synthesis, virtual fitting, and sizing and adjustability allocation methods in the design of an industrial workstation seat for use in five distinct global populations. This work highlights the importance of and opportunities for using ergonomic design principles in DfS efforts. Practitioner Summary: This research demonstrates the relevance of some anthropometry-based ergonomics concepts to the field of design for sustainability. A global design case study leverages human variability considerations in furthering three sustainable design goals: reducing raw material consumption, increasing usage lifetimes and incorporating ethical human resource considerations in design. 相似文献
67.
We report the fluorescence properties of Sm3+-doped lead telluroborate glasses of composition PbF2.TeO2.H3BO3.Sm2O3 as a function of Sm3+ concentration. A Judd-Ofelt scheme was used to determine the intensity parameters and radiative properties of Sm3+ ion. The emission and decay measurements were carried out at 402 nm excitation. Beyond 1.0 mol% Sm3+ concentration, the luminescence quenching is observed. The decay curves of 4G5/2 level are well fitted to a single exponential function. The evaluated radiative properties suggest that the 4G5/2 → 6H7/2 transition is responsible for reddish-orange luminescence which might be used in the development of visible lasers. 相似文献
68.
The simulation model of a transcritical CO2 heat pump dryer presented in Part 1 has been first validated with available experimental data in this part and then used to simulate the heat pump dryer to study the variation of performance parameters such as heating COP, moisture extraction rate, and specific moisture extraction rate. The validation with experimental data shows that the model slightly over predicts the system performance. The possible reasons for the difference between experimental and numerical results are explained. Simulation results show the effect of key operating parameters such as bypass air ratio, re-circulation air ratio, dryer efficiency, ambient condition (temperature and relative humidity), and air mass flow rate. Results show that unlike bypass air ratio and ambient relative humidity, the effect of dryer efficiency, recirculation air ratio, ambient temperature, and air mass flow rate are very significant as far as the system performance is concerned. 相似文献
69.
S. Sathish S. Chaterjee O. N. Awasthi E. S. R. Gopal 《Journal of Low Temperature Physics》1986,63(5-6):423-429
The electron-electron scattering contribution to the ultrasonic attenuation in potassium at low temperatures is evaluated using the Landau Fermi liquid theory. The scattering function is evaluated using the approximation suggested by MacDonald and Geldart. The results are compared with theoretically evaluated electron-phonon scattering contributions. The results show that the electron-electron scattering contribution is of the same order as the electron-phonon scattering contribution in the 2–5 K range. Below 2 K the electron-electron scattering predominates. 相似文献
70.
Anil Kumar Mandeep Kaur Rajeev Kumar Pinaki Ranjan Sengupta Vasantha Raman Gopal Bhatia Kedar Nath Sood 《Journal of Materials Science》2010,45(5):1393-1400
Carbon–copper composites with varying copper to carbon ratio of 0.66–1.5 (by weight) were developed from coal-tar-pitch-derived
green coke (as such or modified with natural graphite) as carbon source and electrolytic grade copper powder at different
heat treatment temperatures (HTTs) of 1000–1400 °C. The physical, mechanical, and electrical properties differ depending upon
the HTT and also on copper to carbon ratio (Cu/C). The composites prepared at HTT of 1100 °C having Cu/C ratio of 0.66 and
0.9 exhibited a high bending strength of 150 and 140 MPa, bulk density of 2.63 and 2.81 gm/cm3, electrical resistivity of 1.6 and 0.96 m Ω cm and shore hardness of 88 and 84, respectively, in spite of well-known inadequate
wettability between copper and carbon. Increasing the temperature from 1100 °C for processing of the composites deteriorated
the properties mainly due to the loss of copper through melting above 1100 °C as revealed by X-ray, scanning electron microscopy,
thermal analysis and EDAX studies. 相似文献