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1.
Stress measurements are required to prevent collapse accidents of structures. Surface SH‐wave acoustoelasticity can measure principal stress difference nondestructively and easily. Currently, surface SH‐wave acoustoelasticity can measure with high precision using a T‐type surface SH‐wave sensor in ideal environments such as in the laboratory. However, in actual environments, it cannot be measured with high precision due to change in the temperature of the specimen. In this paper, temperature dependence of surface SH‐wave acoustoelastic constants was verified to investigate the influence of specimen temperature on surface SH‐wave acoustoelasticity. In addition, the measuring system of surface SH‐wave acoustoelasticity using a cross T‐type surface SH‐wave sensor to reduce the influence of specimen temperature was developed. 相似文献
2.
Preparation of CaCO3‐based biomineralized polyvinylpyrrolidone–carboxymethylcellulose hydrogels and their viscoelastic behavior 下载免费PDF全文
In the blend of natural and synthetic polymer‐based biomaterial of polyvinylpyrrolidone (PVP) and carboxymethylcellulose (CMC), fabrication of CaCO3 was successfully accomplished using simple liquid diffusion technique. The present study emphasizes the biomimetic mineralization in PVP–CMC hydrogel, and furthermore, several properties of this regenerated and functionalized hydrogel membranes were investigated. The physical properties were studied and confirmed the presence of CaCO3 mineral in hydrogel by Fourier transform infrared spectroscopy and Scanning electron microscopy. Moreover, the absorptivity of water and mineral by PVP–CMC hydrogel was studied to determine its absorption capacity. Further, the viscoelastic properties (storage modulus, loss modulus, and complex viscosity) of mineralized and swelled samples (time: 5–150 min) were measured against angular frequency. It is interesting to know the increase of elastic nature of mineralized hydrogel filled with CaCO3 maintaining the correlation between elastic property and viscous one of pure hydrogel. All these properties of biomineralized hydrogel suggest its application in biomedical field, like bone treatment, bone tissue regeneration, dental plaque and tissue replacement, etc. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40237. 相似文献
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Katsuhiro Inomata Tamiko Terahama Rena Sekoguchi Tatsunori Ito Hideki Sugimoto Eiji Nakanishi 《Polymer》2012,53(15):3281-3286
Polypeptide hydrogels were prepared by cross-linking of hydrophobically-modified poly[N5-(2-hydroxyethyl) l-glutamine] having alkyl side chains –CnH2n+1. Chain length of the alkyl group was n = 8, 16, and 18, and their mole fractions in the polypeptide were varied in the range of 0.05–0.16. Shape memory ability of the prepared polypeptide hydrogels was investigated. After deformation at 60 °C, the hydrogel was cooled in order to fix the temporary deformed shape. It was found that crystallization of the alkyl side chains did not occur, and the fixation ability of the hydrogel at 0 °C was low. In the subsequent heating process, the deformed temporary shape spontaneously recovered to the original shape gradually with increasing temperature, in other words, the shape recovery ratio varied with depending on the recovery temperature. From these observations, it was proposed that the shape fixation of the polypeptide hydrogel was achieved by strong segregation of the hydrophobic alkyl chains at low temperature, and the shape recovery of the deformed hydrogel was accompanied by the gradual decrease of the segregation strength with the temperature increase. 相似文献
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[Correction Notice: An erratum for this article was reported in Vol 103(3) of Psychological Bulletin (see record 2008-10688-001). Tables 1 and 2 contain several errors. The correct data is provided in the erratum. These errors do not influence any of the main points or conclusions in this article.] Obesity is a common problem in children and is associated with an increased risk of adult obesity. Twenty-four studies on the behavioral treatment of childhood obesity are reviewed. Studies involving comparisons of behavioral treatment with no treatment or placebos have shown the superiority of behavioral treatment. In addition, the effects of a number of treatment factors on outcome are suggested. These factors include parental involvement, the arrangement of treatment contingencies, and exercise. Several directions for future research are presented, including selecting which children to treat, individualizing treatment, prevention, community programs, and the side effects of weight control. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
A high resolution camera has been developed for the small angle X-ray diffraction measurement of long-periodic layered structures such as Langmuir-Blodgett multilayers, superlattices and liquid crystals. A block collimation system known as a Kratky camera is used to produce a very narrow incident beam. The camera is mounted on a computer-controlled goniometer whose sample holder is rotated around a vertical Θ axis by a pulse motor. Measurements can be carried out in a θ-2θ scan, and also in θ or 2θ scans. Processing of the collected data includes smoothing, and correction for absorption, polarization factor and instrumental broadening. The performance of the present system has been demonstrated by observation of diffraction patterns of a Langmuir-Blodgett film of cadmium arachidate and a GaAs/AlAs superlattice. 相似文献
8.
Epstein Leonard H.; Wing Rena R.; Koeske Randi; Valoski Alice 《Canadian Metallurgical Quarterly》1987,55(1):91
This study was a 5-year follow-up of obese children who participated in a family-based behavioral weight-control program targeting and reinforcing children and parents for weight loss (Epstein, Wing, Koeske, Andrasik, & Ossip, 1981). Children in the parent-plus-child group showed significantly greater weight reductions after 5 years (–22.7% overweight) than did children in a child-alone target group or in a no-target control group (4.3% and 8.2% overweight, respectively). One third of children in the parent-plus-child group were within 20% of normal weight in comparison with 5% of the children in the no-target control group. Height percentile decreased from the 72nd to the 60th percentile; these changes were negatively related to weight change. These children remained taller than the average child after weight loss, and children of short and medium-height parents were still relatively taller than their parents after 5 years. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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We examined situational antecedents of dieting relapse crises and dieters' attempts to cope with temptations to overeat. We analyzed postreatment interviews with 57 obese Ss with Type II diabetes, comparing situations in which Ss lapsed with those in which they overcame temptation to overeat. Cluster analysis yielded 3 categories of relapse crises: mealtime, low-arousal, and emotional upset situations. The cluster differed in outcome: Upset situations almost always resulted in overeating; situational factors, especially food-related cues, increased relapse risk; but performance of coping was the strongest correlate of outcome. Cognitive and behavioral coping responses were each equally associated with positive outcomes. When Ss reported combining both types of coping, they were less likely to report overeating. The dynamics of relapse crises among dieters resemble those that govern relapse crises in addictive behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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This longitudinal study examined how depressive symptoms relate to children's self-perceptions and to estimates of children's cognitive distortions about the self in a nonclinical sample of children who were followed from 4th grade (n=248) through 6th grade (n=227). Report card grades measured children's academic competence, and teachers' ratings of children's level of peer acceptance at school indicated social acceptance. Self-reported depressive symptoms predicted a change in children's negative views of the self. Moreover, the self-perceptions of children who exhibited more symptoms of depression appeared to reflect an underestimation of their actual competence. Children's negative self-perceptions and underestimations about the self were not associated with a subsequent change in depressive symptoms. The implications of the findings for cognitive theories of depression and future research with this population are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献