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排序方式: 共有2305条查询结果,搜索用时 31 毫秒
111.
Tünçay Mehmet Masum Nguyen Lucie Hendrickx Philippe Brochu Mathieu 《Journal of Materials Engineering and Performance》2016,25(10):4521-4528
Journal of Materials Engineering and Performance - Spark plasma sintering (SPS) is a powder metallurgy process that sinters powder materials within a short time by simultaneous application... 相似文献
112.
Safdar Muhammad Ozaslan Mehmet 《Journal of Inorganic and Organometallic Polymers and Materials》2022,32(5):1819-1827
Journal of Inorganic and Organometallic Polymers and Materials - In this study, the nanosized spherical erythromycin capped gold nanoparticles (eryth-Au(0)NPs) were fabricated for the first time.... 相似文献
113.
Effects of reactive and nonreactive POSS types on the mechanical,thermal, and morphological properties of plasticized poly(lactic acid)
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The aim of this study is to investigate the effects of the reactive and nonreactive polyhedral oligomeric silsesquioxane (POSSs) types and their composition on the mechanical, thermal, and morphological properties of poly(ethylene glycol) plasticized poly(lactic acid) (PLA) composites prepared with melt compounding. The results showed that the incorporation of POSS decreased the melt viscosity of the compounds regardless of POSS type. The lowest viscosity was obtained with epoxy‐POSS, which is the only one that is liquid at processing temperature in comparison to the others. It was revealed from the mechanical tests that the toughness‐related properties such as impact strength and elongation at break improved by the addition of POSS without remarkable deterioration in stiffness. The chemical structure of the POSS influenced the level of dispersion and hence the mechanical performance of the composites. Octaisobutyl‐POSS, being the nonreactive and nonpolar one, had the best dispersion among the other reactive and polar POSS types. The glass transition temperature of the matrix decreased in the presence of POSS types. In addition, the POSS particles also had an impact on the crystallization of PLA. The thermal stability of the composites improved in the presence of POSS particles with respect to the POSS content and the POSS type. POLYM. ENG. SCI., 54:264–275, 2014. © 2013 Society of Plastics Engineers 相似文献
114.
The concentrations of myricetin in medicinal plants such as Rosa canina L. (rosa hip), Terebinthina chica L. (terebinth), Urtica dioica L. (nettle), and Portuca oleracea L. (purslane) were determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS). The aglycones of myricetin were extracted using methanol–ascorbic acid– hydrochloric acid, methanol–hydrochloric acid, and methanol, separated within 5 min, and individually quantitated in the positive ionization mode using optimized conditions for HPLC-MS. Methanol–ascorbic acid–hydrochloric acid was the optimum extraction solvent. The myricetin concentration in the plants were between 3 and 58 mg kg?1, with a limit of quantification equal to 0.1 mg L?1. 相似文献
115.
Baki Hazer Songun I. Demirel Mehlika Borcakli Mehmet S. Eroglu Miko Cakmak Burak Erman 《Polymer Bulletin》2001,46(5):389-394
Summary
Poly(-3-hydroxy alkanoate) containing unsaturated side chains, PHA-soybean, were produced by feeding Pseudomonas oleovorans with soybean oily acids obtained from soybean oil. Unsaturation of PHA-soybean were found to be 10 mol-% of unsaturated side
chains.
Main saturated part of the biopolymer was Poly(3-hydroxy octanoate) with minor hexanoate and decanoate units. PHA films were
crosslinked via free radical mechanism by means of thermally or under UV irradiation in the presence of benzoyl peroxide,
benzophenon, and /or ethylene glycol dimethacrylate (EGDM). Crosslinking yield of the PHA films were found to be from 81 to
93 wt.-% from the sol-gel analysis. Swelling properties of the crosslinked PHA films in chloroform and toluene were also studied.
Mc values of crosslinked PHAs were also calculated using Flory-Rehner equation. The crosslinked biopolyester obtained by thermally
at 60 °C with benzoyl peroxide indicated the highest crosslinking density. Glass transition temperatures (Tg) of crosslinked
biopolyester samples were changed from −33 to −45 °C while that of PHA-soybean was −60 °C.
Received: 16 June 2000/Revised version: 22 January 2001/Accepted: 20 May 2001 相似文献
116.
117.
Mehmet Fatih Cengiz M. Zeki Durak Sukriye Nilufer Ayşe Kevser Bilgin 《International Journal of Food Properties》2013,16(4):746-756
An ion chromatographic method for the quantitative determination of free cyanide in bottled natural mineral waters were measured in terms of selectivity, linearity, the limit of detection, limit of quantification, repeatability, precision, and accuracy. Chromatographic separation of free cyanide ions was accomplished with an anion-exchange column and detected by pulsed amperometric detection with a silver working electrode. The method was found to be selective, linear (r2 = 0.999) at a concentration range of 0.5 to 134 μg L?1, precise, and accurate. Recovery values of free cyanide in all classes of natural mineral water varied from 65.9 ± 1.6 to 95.2 ± 0.7 at different spiking levels (5–70 μg L?1). Parameters (total dissolved solids, mineral interferences, and added sodium hydroxide) affecting the recovery values were studied in this project. The limit of detection and limit of quantification were found to be 0.295 and 0.983 μg L?1, respectively. The proposed method was applied to 27 different brands of commercially available bottled natural mineral water products sold in Turkish markets. These natural mineral waters were classified as: (i) very low mineral concentration, (ii) low mineral concentration, (iii) intermediate mineral concentration, and (iv) high mineral concentration based on their total dissolved solids contents according to European Union Directive (Directive 80/777/EEC). Levels of free cyanide residues in the samples ranged from > limit of detection to 6.12 μg L?1. The highest average concentration of free cyanide residues was found in the class of “high mineral concentration waters.” However, the determined free cyanide values in all of the tested natural mineral water samples were found to be within the limits of European Union legislation. 相似文献
118.
低噪声APD偏置电路 总被引:2,自引:0,他引:2
1APD的特性雪崩光电检测器 (APD)和PIN二极管通常被作为接收器用于光通信中。其中APD适合于高灵敏度和高带宽的光接收电路。但这种器件在工作时需要施加一个反向结压 ,这样 ,当接收到射线时产生的电子空穴对会被外加电场收集并转换为电流 ,其电流强度正比于射线强度。另外 ,工作时施加在器件上的反向偏置电压会引发雪崩效应 ,其雪崩增益可通过改变偏压来进行调节。这就有可能对光纤接收器的增益进行优化。然而 ,要得到满意的雪崩增益 ,就必须给APD提供一个比较高的反向偏压。很多APD需要40V~60V的偏压 ,有些器件… 相似文献
119.
Modelling and boundary control for the Burgers equation is studied in this paper. Modelling has been done via processing of numerical observations through proper orthogonal decomposition (POD) with Galerkin projection. This results in a set of spatial basis functions together with a set of ordinary differential equations (ODEs) describing the temporal evolution. Since the dynamics described by the Burgers equation are non-linear, the corresponding reduced-order dynamics turn out to be non-linear. The presented analysis explains how the free boundary condition appears as a control input in the ODEs and how controller design can be accomplished. The issues of control system synthesis are discussed from the point of practicality, performance and robustness. The numerical results obtained are in good compliance with the theoretical claims. A comparison of various different approaches is presented. 相似文献
120.
Mehmet Demirbag David G. Collings Ekrem Tatoglu Kamel Mellahi Geoffrey Wood 《Management International Review》2014,54(3):325-359
This study examines the association between the usage of high-performance work systems (HPWS) by subsidiaries of multinational enterprises (MNEs) in Turkey and employee and subsidiary level outcomes. The study is based on a survey of 148 MNE subsidiaries operating in Turkey. The results show that the usage of HPWS has a significant positive impact on employee effectiveness. However, their impact on employee skills and development, and organizational financial performance are far less clear. Our findings highlight the extent to which HWPS need to be adapted to take account of context-specific institutional realities. 相似文献