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Mian A Newaz G Vendra L Rahman N Georgiev DG Auner G Witte R Herfurth H 《Journal of materials science. Materials in medicine》2005,16(3):229-237
Bioencapsulation of medical implant devices, and neural implant devices in particular, requires development of reliable hermetic joints between packaging materials that are often dissimilar. Titanium-polyimide is one of the biocompatible material systems, which are of interest to our research groups at Wayne State University and Fraunhofer USA. We have found processing conditions for successful joining of titanium with polyimide using near-infrared diode lasers or fiber lasers along transmission bonding lines with widths ranging from 200 to 300 m. Laser powers of 2.2 and 3.8 W were used to create these joints. Laser-joined samples were tested in a microtester under tensile loading to determine joint strengths. In addition, finite element analysis (FEA) was conducted to understand the stress distribution within the bond area under tensile loading. The FEA model provides a full-field stress distribution in and around the joint that cause eventual failure. Results from the investigation provide an initial approach to characterize laser-fabricated microjoints between dissimilar materials that can be potentially used in optimization of bio-encapsulation design. 相似文献
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The equations governing the boom-assisted deployment of a lifeboat from a moving support are formulated in three dimensions using Kanes method, accounting for the coupling of the dynamics of the boom and lifeboat. The effect of wind loading is included. At splashdown we assume a controlled water entry and hence the buoyancy force, but not impact force, is modeled. The equations are solved numerically using a standard Runge-Kutta MATLAB routine. Comparison with a known solution for a special case is illustrated. 相似文献
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Kyoung-Su?ImEmail author Ming-Chia?Lai Suck-Ju?Yoon 《Journal of Mechanical Science and Technology》2003,17(12):2053-2065
The current trend in automotive finishing industry is to use more electrostatic rotating bell (ESRB) need space to their higher
transfer efficiency. The flow physics related with the transfer efficiency is strongly influenced by operating parameters.
In order to improve their high transfer efficiency without compromising the coating quality, a better understanding is necessary
to the ESRB application of metallic basecoat painting for the automobile exterior. This paper presents the results from experimental
investigation of the ESRB spray to apply water-borne painting. The visualization, the droplet size, and velocity measurements
of the spray flow were conducted under the operating conditions such as liquid flow rate, shaping airflow rate, bell rotational
speed, and electrostatic voltage setting. The optical techniques used in here were a microscopic and light sheet visualization
by a copper vapor laser, and a phase Doppler particle analyzer (PDPA) system. Water was used as paint surrogate for simplicity.
The results show that the bell rotating speed is the most important influencing parameter for atomization processes. Liquid
flow rate and shaping airflow rate significantly influence the spray structure. Based on the microscopic visualization, the
atomization process occurs in ligament breakup mode, which is one of three atomization modes in rotating atomizer. In the
spray transport zone, droplets tend to distribute according to size with the larger drops on the outer periphery of spray.
In addition, the results of present study provide detailed information on the paint spray structure and transfer processes. 相似文献
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Daniel?G.?GeorgievEmail author Taslema?Sultana Ahsan?Mian Greg?Auner Hans?Herfurth Reiner?Witte Golam?Newaz 《Journal of Materials Science》2005,40(21):5641-5647
Laser-fabricated joints of sub-millimeter widths between biocompatible, dissimilar materials have the potential for application
as encapsulation of miniature implantable biomedical devices. In this work, we briefly describe the laser joining method of
a very promising system, polyimide/titanium-coated borosilicate glass, and present results from characterization of such laser
joints by means of mechanical failure (tensile) tests, optical and scanning electron microscopy, X-ray photoelectron spectroscopy
(XPS) and Raman spectroscopy. Our results suggest that the formation of the joints is a result of the creation of strong chemical
bonds between Ti-containing species and certain polymeric functional groups. Mechanical tensile strength failure testing showed
that such joints experience some degradation as a result of soaking in physiological solutions. This degradation is limited
and, even after relatively long-term exposure the joints retain considerable strength. 相似文献
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Victor?BerdichevskyEmail author Khanh?Chau?Le 《International Journal of Fracture》2005,133(4):L47-L54
A theory of microcracks nucleation in brittle solids is proposed. Theoretical predictions are compared with the experimental data for silica glass. 相似文献
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Modification of milk fat both by partially replacing saturated FA with oleic acid (18∶1) and by increasing calcium intake
independently reduces plasma cholesterol. Whether modification of both factors together would synergistically reduce plasma
cholesterol is unknown. Seventy-two male golden Syrian hamsters were separated into four diet treatment groups (n=18/group) and fed ad libitum for 7 wk. Diets contained either modified milk fat (MMF) or regular milk fat (RMF) with either 0.5% (MMF and RMF) or 1.3%
calcium (w/w) (MMFC and RMFC). All diets contained 11% test fat, 4% soybean oil, and 0.15% cholesterol (w/w). During the last
week, feces were collected for three consecutive days for analysis of fecal FA, cholesterol, and calcium excretion. Overnight-fasted
animals were sacrificed, and plasma and livers were collected for lipid analysis. Neither MMF nor additional calcium significantly
affected plasma lipids. However, significant interactions existed between MMF and additional calcium for the ratio of LDL
cholesterol to HDL cholesterol (LDL/HDL), indicating that increased calcium intake reduced this ratio only in RMF animals.
In addition, MMF reduced LDL/HDL relative to RMF. MMF significantly increased hepatic total and esterified cholesterol. Additional
calcium significantly increased fecal calcium and saturated FA (SFA) excretion, whereas MMF significantly reduced SFA excretion.
RMFC induced the highest excretion of 16∶0 among all groups. Replacement of SFA with 18∶1 in the MMF reduced the impact of
high calcium on LDL/HDL. Additional calcium reduced LDL/HDL only in the presence of RMF, which may be achieved through an
increased excretion of 16∶0. 相似文献
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