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11.
G.O. Phillips S. Al-Assaf A. du Plessis 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,265(1):390-393
Using a mediating alkyne gas during the radiation treatment prevents the degradation of natural and synthetic polysaccharides and proteins. The product has higher viscosity and is more elastic than the original material and, therefore, gives enhanced functionality. Protein, within demineralised bone, too can be modified to give enhanced osteoinductive capacity after transplantation. Thus new functionalities can be achieved from the new products produced in food and medical products. 相似文献
12.
13.
Karen S. Servilla Antonios H. Tzamaloukas Charles Carter Glen H. Murata 《Hemodialysis international. International Symposium on Home Hemodialysis》2002,6(1):35-39
We developed a composite compliance index as the sum of the compliance scores for interdialytic weight gain (IDWG), pre‐dialysis serum potassium and phosphorus concentrations (each scored from zero to 3, with 3 indicating the poorest compliance), and skipping hemodialysis sessions (scored from zero to 9, with 9 indicating the poorest compliance). We used this composite score to prospectively evaluate compliance in 25 prevalent hemodialysis patients over a period of 1 year. We then followed these patients for another 3.5 years. The patients studied were divided into two groups: group A (poor compliance) consisted of 9 subjects with composite score ≥ 9 (13.2 ± 3.2); group B (better compliance) consisted of 16 subjects with composite score < 9 (4.7 ± 1.8). Age, duration of hemodialysis, and frequency of diabetes mellitus did not differ between the groups. Group A contained higher fractions of subjects with history of alcoholism (66.7% vs 12.5%, p = 0.010), other substance addiction (44.4% vs 0%, p = 0.010), and severe psychosocial problems (88.9% vs 18.8%, p = 0.002). Mean survival from the beginning of observation, estimated by actuarial life‐table survival analysis, was 1.19 years in group A and 2.60 years in group B (p = 0.0265). A composite compliance index incorporating domains indicating adherence to diet, medications, and dialysis schedule identified other behavioral problems in poorly compliant patients. Hemodialysis patients characterized by this composite index as poorly compliant had shortened survival. 相似文献
14.
This paper presents an application of digital signal processing to data acquired by the radio imaging method (RIM) that was adopted to measure moisture distribution inside the human body. RIM was originally developed for the mining industry; we are applying the method to a biomedical measurement because of its simplicity, economy, and safety. When a two‐dimensional image was constructed from the measured data, the method provided insufficient resolution because the wavelength of the measurement medium, a weak electromagnetic wave in a VHF band, was longer than human tissues. We built and measured a phantom, a model simulating the human body, consisting of two water tanks representing large internal organs. A digital equalizer was applied to the measured values as a weight function, and images were reconstructed that corresponded to the original shape of the two water tanks. As a result, a two‐dimensional image containing two individual peaks corresponding to the original two small water tanks was constructed. The result suggests the method was applicable to biomedical measurement by the assistance of digital signal processing. This technique may be applicable to home‐based medical care and other situations in which safety, simplicity, and economy are important. 相似文献
15.
The physical preconditions are considered for the temperature of a body to influence the force of gravity experienced by it. The results are given of experiments on weighing metal rods heated by ultrasound which confirm a dependence of the weight of the rods on their temperature. 相似文献
16.
A generalized equation was derived to calculate the melting temperatures of homopolymers and copolymers. The Gibbs‐Thomson equation for homopolymers and a modified application to copolymers were derived using the proposed equation. The melting temperature Tm0 in the Flory equation corresponds to the melting temperature TmC,∞ of copolymer crystals with stems of infinite length. Also, TmC,n*, the melting temperature for copolymer crystals with stems containing the maximum possible number of structural units, n*, should be used instead of Tm0 as the basis of supercooling in crystallization. The proposed equation shows good agreement with experimental data for α‐alkene‐ethylene homogeneous copolymers. 相似文献
17.
This paper deals with the non-steady-state kinetics of direct thermal initiated polymerization. The initiation is assumed to be a bimolecular reaction of the monomer. The relationship between the radical concentration and the monomer conversion is rigorously derived. In further treatment a few very close approximations are introduced based on the fact that the number of monomer molecules reacting in the initiation step is much less than that consumed in the propagation step for a process producing high polymer, and the value of the rate constant for propagation or chain transfer is much lower than that for chain termination. Expressions for various molecular parameters, such as molecular weight distribution, number-average and weight-average degrees of polymerization, and dispersity, are given. Several numerical examples are provided. 相似文献
18.
Wood has long traditions as a building material, and is often used in construction elements, and as interior and exterior surfaces in the Nordic countries. In most applications, there are reaction to fire requirements to products used as surfaces, e.g. in escape routes and larger public spaces. Most wood products will therefore have to be treated with fire retardant (FR) agents to fulfil the strict requirements to properties connected to heat release and flame spread. Unfortunately, FR agents usually also increase the smoke production, as they cause a more incomplete combustion of the wood. The wood product manufacturers seek to find the optimal amount of FR additives where both heat release and smoke production in the classifying test are within the requirements given in the building regulations. This paper describes models for prediction of the European reaction to fire classes of wood products. The models are based on multivariate statistical analysis, and use test results from the cone calorimeter test as input. The presented models are, with very good precision, able to predict which Euroclass and additional smoke class a wood based product would obtain if it were to be tested in the single burning item test. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
19.
Polyurethanes were prepared from pure 4,4′-diphenylmethane diisocyanate (MDI), 1,4-butane diol (BDO) or 1,2-ethane diol (EDO) and α,ω-hydroxyl poly(propylene oxide) (PPO) by reaction injection moulding (RIM). Hard segment (MDI + BDO or EDO) level was 45–50 wt%. The PPO had about 20% ethylene oxide copolymerized in at the chain ends to provide 80% primary OH end groups. Mn was varied from 2000 to 4000. Dibutyl tin dilaurate catalyst and mould temperature were varied. Dynamic mechanical, wide-angle X-ray, differential scanning calorimeter, molecular weight and tensile elongation measurements were made on the RIM polyurethanes. At low reaction rates (low catalyst or temperature) highly crystalline, well phase separated but low molecular weight polymers were produced. At high catalyst or temperature levels more poorly phase separated but high molecular weight, tough polymers resulted. Higher Mn PPO gave better phase separation and EDO gave higher melting temperatures. Preventing hard segment crystallinity by substituting asymmetric MDI or glycols resulted in phase compatibility. 相似文献
20.
钢结构稳定设计——理论与实践 总被引:2,自引:0,他引:2
本文提出了实际工程结构的非线性理论设计和分析方法(NIDA),并以澳门回归纪念馆的设计为例,展示了本方法的优越性.在设计过程中,设计者无需假设K系数和有效长度,在结构分析完成后便可迅速完成设计,因此本文提出的方法既经济又便利.尽管对于钢框架在往复荷载及动力荷载作用下的弹塑性大位移分析已经非常成熟,但本文的方法开创了结构的非线性分析及设计的新纪元,能够对现行的设计方法理论起到巨大的推动作用. 相似文献