Conductive adhesive with transient liquid‐phase sintering technology for high‐power device applications

A highly reliable conductive adhesive obtained by transient liquid‐phase sintering (TLPS) technologies is studied for use in high‐power device packaging. TLPS involves the low‐temperature reaction of a low‐melting metal or alloy with a high‐melting metal or alloy to form a reacted metal matrix. For a TLPS material (consisting of Ag‐coated Cu, a Sn96.5‐Ag3.0‐Cu0.5 solder, and a volatile fluxing resin) used herein, the melting temperature of the metal matrix exceeds the bonding temperature. After bonding of the TLPS material, a unique melting peak of TLPS is observed at 356 °C, consistent with the transient behavior of Ag₃Sn + Cu₆Sn₅ → liquid + Cu₃Sn reported by the National Institute of Standards and Technology. The TLPS material shows superior thermal conductivity as compared with other commercially available Ag pastes under the same specimen preparation conditions. In conclusion, the TLPS material can be a promising candidate for a highly reliable conductive adhesive in power device packaging because remelting of the SAC305 solder, which is widely used in conventional power modules, is not observed.     

Highly Bendable and Rotational Textile Structure with Prestrained Conductive Sewing Pattern for Human Joint Monitoring

Human joints have respective ranges of motion and joint forces corresponding to each kind of joint; this necessitates considerations of the characteristics of human joints to fabricate wearable strain sensors conformable to the human body, and capable of precisely monitoring complex motions of the human body. In the present study, the “all textile‐based highly stretchable structure” that is capable of precisely sensing motions (folding and rotation) of the human joints (finger, wrist, elbow, spine, and knee) is fabricated by optimizing patterns (straight, blind, and zigzag) of conductive yarns employed as the conductive part of the strain sensor, and several textile substrates (braided elastic fabric, knit fabric, and woven fabric), having preferable elasticity and conformability employed for the fabrication of strain sensors suitable for human joints. In particular, the technology, enabling the prestraining of textile substrate, is exploited to fabricate a strain sensor that is capable of outputting selective signals corresponding to the folding motion of the spinal joint over a predetermined angle of motion, and the gait pattern of the wearer of the sensor, attached to his or her knee joint doing folding and rotational motions, is analyzed.     

Analyzing the Variability in Low-Flow Projections under GCM CMIP5 Scenarios

Water Resources Management - The present study considered the impacts of global climate model (GCM) selection in the Couple Model Intercomparison Phase 5 (CMIP5) scenarios on the low-flow...     

ACE-Asia intercomparison of a thermal-optical method for the determination of particle-phase organic and elemental carbon

A laboratory intercomparison of organic carbon (OC) and elemental carbon (EC) measurements of atmospheric particulate matter samples collected on quartz filters was conducted among eight participants of the ACE-Asia field experiment The intercomparison took place in two stages: the first round of the intercomparison was conducted when filter samples collected during the ACE-Asia experiment were being analyzed for OC and EC, and the second round was conducted after the ACE-Asia experiment and included selected samples from the ACE-Asia experiment Each participant operated ECOC analyzers from the same manufacturer and utilized the same analysis protocol for their measurements. The precision of OC measurements of quartz fiber filters was a function of the filter's carbon loading but was found to be in the range of 4-13% for OC loadings of 1.0-25 microg of C cm(-2). For measurements of EC, the precision was found to be in the range of 6-21% for EC loadings in the range of 0.7-8.4 microg of C cm(-2). It was demonstrated for three ambient samples, four source samples, and three complex mixtures of organic compounds that the relative amount of total evolved carbon allocated as OC and EC (i.e., the ECOC split) is sensitive to the temperature program used for analysis, and the magnitude of the sensitivity is dependent on the types of aerosol particles collected. The fraction of elemental carbon measured in wood smoke and an extract of organic compounds from a wood smoke sample were sensitive to the temperature program used for the ECOC analysis. The ECOC split for the three ambient samples and a coal fly ash sample showed moderate sensitivity to temperature program, while a carbon black sample and a sample of secondary organic aerosol were measured to have the same split of OC and EC with all temperature programs that were examined.     

Wheat sprouts (Triticum aestivum Linn.) cultured by a smart farm system ameliorate NAFLD through the AMPK-mediated SREBP signaling pathway

Wheat is cultivated worldwide and is the most widely distributed food crop. Wheat is a staple crop in many countries. However, the effects of various cultivation methods on the efficacy of wheat sprouts have not been determined. This study investigated wheat sprouts obtained using a standardized smart farm system (WS-S) to improve the effects of non-alcoholic fatty liver disease (NAFLD) and molecular mechanism. Wheat sprouts significantly attenuated the accumulation of lipid droplets in FFA-induced HepG2 cells through AMPK pathway activity. In vivo experiments showed that WS-S significantly lowered body weight gain and decreased adipose tissue, lipid, aspartate transaminase, and alanine aminotransferase levels in HFD/F-treated mice. Furthermore, WS-S stimulated the phosphorylation of ACC and peroxisome proliferator-activated receptor alpha via the AMPK pathway and inhibited SREBP-1/FAS signaling to inhibit de novo adipogenesis and increase fatty acid oxidation. These results suggest that WS-S ameliorates NAFLD by regulating fatty acid metabolism via the AMPK pathway.

     

Cloning and functional characterization of the SUR2/SYR2 gene encoding sphinganine hydroxylase in Pichia ciferrii

Saccharomyces cerevisiae sphinganine C4-hydroxylase encoded by the SUR2 gene catalyses the conversion of sphinganine to phytosphingosine. We isolated the SUR2 gene from Pichia ciferrii using nucleotide sequence homology to S. cerevisiae SUR2 to study hydroxylation of sphinganine in the sphingoid base overproducing yeast P. ciferrii. A positive clone was confirmed by nucleotide sequencing. A syringomycin-E resistance phenotype of a S. cerevisiae sur2-null mutant was complemented by expression of the cloned P. ciferrii SUR2 gene. Restoration of phytosphingosine production in the complemented strain was also confirmed, indicating that the cloned gene is a functional homologue of S. cerevisiae SUR2. .     

A study on reliability centered maintenance planning of a standard electric motor unit subsystem using computational techniques

The design and manufacture of urban transportation applications has been necessarily complicated in order to improve its safety. Urban transportation systems have complex structures that consist of various electric, electronic, and mechanical components, and the maintenance costs generally take up approximately 60% of the total operational costs. Therefore, it is essential to establish a maintenance plan that takes into account both safety and cost. In considering safety and cost limitations, this research introduces an advanced reliability centered maintenance (RCM) planning method using computational techniques, and applies the method to a standard electric motor unit (EMU) subsystem. First, this research devises a maintenance cost function that can reflect the current operating conditions, and maintenance characteristics, of components by generating essential cost factors. Second, a reliability growth analysis (RGA) is performed, using the Army Material Systems Analysis Activity (AMSAA) model, to estimate reliability indexes such as failure rate, and mean time between failures (MTBF), of a standard EMU subsystem, and each individual component Third, two optimization processes are performed to ascertain the optimal maintenance reliability of each component in the standard EMU subsystem. Finally, this research presents the maintenance time of each component based on the optimal maintenance reliability provided by optimization processesand reliability indexes provided by the RGA method. This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim Myung-Won Suh is a professor of Mechanical Engineering. During 1986–1988, he worked for Ford motor company as researcher. During 1989–1995, he worked in the technical center of KIA motors. He earned a BS degree in Mechanical Engineering from Seoul National University and an MS degree in Mechanical Engineering from KAIST, South Korea. He obtained his Doctorate at the University of Michigan, USA, in 1989. His research areas include structure and system optimization, advanced safety vehicle and reliability analysis & optimization. Chul-Ho Bae is a PhD candidate at Sungkyunkwan University in Suwon, South Korea. He ac-complished fellowship work as researcher at Mississippi State University, USA, in 2003 and 2005. He worked in Institute of Advanced Machinery and Technology (IMAT) as a Research Assistant in 2004. He was a part time Lecturer in computer aided Mechanical Engineering of Ansan College of Technology, Suwon Science College, and Osan College during 2004–2005. He took a BS Degree in Mechanical Design and an MS Degree in Mechanical Engineering from the Sungkyunkwan University. His research interests include computer aided engineering, reliability engineering, and optimization.     

Magnetic resonance imaging of renal lymphoma with computed tomography correlation

The magnetic resonance (MR) imaging and computed tomography (CT) findings in four patients (five kidneys) with non-Hodgkin's lymphoma involving the kidneys and perirenal spaces are presented. The patterns of disease in each case were as follows: bilateral renal nodules, infiltration in the perirenal space, infiltration in the perirenal space with renal involvement, and direct invasion from contiguous retroperitoneum. On plain CT, the lesions showed slight hyperdensity (three kidneys) and isodensity (two kidneys) as compared with normal renal parenchyma. But all lesions appeared as hypodense masses with more definite margins after contrast enhancement. MR imaging findings showed iso- or slight hypointense masses on T1-weighted images and definite hypointense masses on T2-weighted images as compared with the signal intensity of the renal cortex. Dynamic imaging and conventional delayed T1-weighted imaging following Gd-DTPA injection showed no significant enhancement of the lesions. In comparison with contrast enhanced CT, despite its poorer resolution, T2-weighted MR imaging showed nearly the same accuracy in the evaluation of number and extent of the lesions without contrast medium administration. MR imaging was also useful to evaluate the patency of vessel lumen surrounded by tumor mass and to determine the location and extent of huge lesions by its multiplanar imaging capabilities.     

NO/cGMP pathway is involved in exocrine secretion from rat pancreatic acinar cells

OBJECTIVE: To identify factors associated with the initiation of breast-feeding in a predominantly Puerto Rican population living in inner-city Hartford, Conn. DESIGN: Retrospective study of 144 Latino women (mean +/- standard deviation age = 26.3 +/- 5.7 years) with children at least 1 year old but younger than 6 years old (mean +/- standard deviation age = 3.0 +/- 1.2 years) at the time of the survey. Women were recruited from agencies sponsoring health programs for mothers and children. They were interviewed in their homes (69%) or at the Hispanic Health Council, Hartford, Conn (31%). SUBJECTS/SETTING: Low-income Latino women who had at least 1 preschooler at the time of the interview. The women lived in inner-city Hartford, and the overwhelming majority were Puerto Rican and received welfare assistance and food stamps. Seventy-eight percent of the women chose to be interviewed in Spanish; the other 22% were interviewed in English. STATISTICAL ANALYSES: Explanatory variables that related to breast-feeding initiation (P < or = .2) in bivariate chi 2 analyses were entered into a multivariate logistic regression model that was reduced using backward stepwise elimination procedures. RESULTS: Multivariate analyses indicated that breast-feeding the previous child, shorter length of maternal residence in the United States, not receiving prenatal bottle-feeding advice, more recent birth, and higher birth weight were positively associated with breast-feeding initiation. A major reason for choosing not to breast-feed was that women felt socially uncomfortable doing it. APPLICATIONS: Breast-feeding initiation was more likely in Latino women who received prenatal breast-feeding counselling and postpartum support. Mothers of low-birth-weight infants and women breast-feeding for the first time may need additional help. These findings can be used by programs like the Special Supplemental Nutrition Program for Women, Infants, and Children to increase breast-feeding initiation.