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排序方式: 共有693条查询结果,搜索用时 15 毫秒
1.
Hydrophilic polymer networks (hydrogels) based on sodium carboxymethylcellulose (NaCMC) and polycarboxylic acids (oxalic, succinic, citric and adipic) as cross-linking agents are synthesized by esterification reaction; one series of NaCMC hydrogels cross-linked with citric acid is prepared with acrylamide and acrylic acid (Aam/Aac) copolymers using the design of semi-interpenetrating polymer networks (semi-IPN), in order to increase their potential application for flocculation purposes. The Infrared spectroscopy (FTIR) of hydrogels confirms the esterification reaction between NaCMC and cross-linking agents. Results of swelling measurements show that citric acid in the amount of 15 wt% gives the hydrogels with the best absorption capacity. The results of Differential scanning calorimetry (DSC) and Thermal gravimetric analysis (TGA) show no significant difference in thermal properties of neat and semi-interpenetrating NaCMC hydrogels. The amorphous nature of hydrogels is confirmed by X-ray diffraction analysis (XRD). The results of flocculation study show that combination of NaCMC network and Aam/Aac copolymer with initial mass ratio of 10/90 creates a theoretical platform for the production of flocculant which could show high efficacy in purifying of water dominated by positively charged particles. 相似文献
2.
5类网络电缆由四对双绞线组成,并有耐用的外套,这种电缆能为分量视频信号的传输提供一种通用而有良好性价比的选择。三个线对可以承载RGB视频信号,而第四对线可以承载音频信号、同步信号和其它传输信号。不幸的是,5类电缆缺乏屏蔽,因此容易遭受共模噪声耦合 相似文献
3.
This study examined the role of marital conflict structure--who desires and requests change versus who responds to the change request--in spouses' cardiovascular responses to marital interactions. Forty-one couples discussed 2 marital topics: one in which the wife desired change in the husband, and one in which the husband desired change in the wife. Cardiovascular responses were assessed at 2-min intervals. Results indicated that marital conflict structure moderates cardiovascular reactivity during negative marital interactions: Husbands and wives whose interactions were characterized by high levels of negative behavior showed the most pronounced diastolic blood pressure reactivity, but only when they were in the role of desiring change in their spouses. Implications for gender differences in marital conflict physiology are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Crabbe John C.; Gallaher Edward S.; Phillips Tamara J.; Belknap John K. 《Canadian Metallurgical Quarterly》1994,108(1):186
Mice from 15 inbred strains (n?=?27–40 per strain) differed in sensitivity to ethanol-induced effects on open-field activity, hypothermia, rotarod ataxia, and anesthesia. Sensitivities to the different behavioral responses were generally uncorrelated. This suggests that the genetic determinants of behavioral sensitivity to one domain of ethanol effects are unrelated to those determining other responses. On the other hand, some variables were genetically related. For example, those strains sensitive to the loss of righting reflex induced by higher doses of ethanol showed reduced activity in the open field at lower doses and were more sensitive to ethanol-induced decreases in rearing. More generally, the pattern of results suggests that genetically influenced sensitivity to ethanol is not a monolithic phenomenon. Rather, it is specific to the particular response variable studied. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Various physical parameters of gravity pipes such as gravity pipe diameter, the inclination of the gravity pipe, the cone angle, temperature of the discharged material and the rate of air counter flow into the gravity pipe were studied. The results obtained from the pipe diameter and cone angle experiments showed that the mass flow rate was proportional to (D-1.4d)2.5 and also to θ-0.5. The results from the pipe inclination experiment showed the existence of an angle of inclination for maximum flow, which was also reported by Wieghardt [Uber einige versuche an stromungen in sand. Ingenieur Archived 20, 109-115]. The air flow experiment also showed that the mass flow rate was inversely proportional to the air counter-flow rate, and strongly influenced by the material properties. Results from the temperature experiment showed that the temperature of the material had slight effect on the mass flow rate for the temperature range that was used in the experiment. Flow visualization images showed formation of solid plugs in the pipe that played a part in influencing the behaviour and mass flow rate of solids in the system. 相似文献
6.
Lutgendorf Susan K.; Russell Daniel; Ullrich Philip; Harris Tamara B.; Wallace Robert 《Canadian Metallurgical Quarterly》2004,23(5):465
This study prospectively examined the relationship between religious attendance, interleukin-6 (IL-6) levels, and mortality rates in a community-based sample of 557 older adults. Attending religious services more than once weekly was a significant predictor of lower subsequent 12-year mortality and elevated IL-6 levels (> 3.19 pg/mL), with a mortality ratio of .32 (95% confidence interval [CI] = 0.15,0.72; p 相似文献
7.
Pavel L. Katsel Tamara M. Dmitrieva Rashid B. Valeyev Yuri P. Kozlov 《Journal of chemical ecology》1992,18(11):2003-2010
Three components of the male yellowfin Baikal sculpin pheromonal signal have been isolated from urine by diethyl ether extraction, thinayer chromatography (TLC), and high-performance liquid chromatography (HPLC). Using mass spectrometry, we have identified two of them as testosterone (T) and 11-hydroxytestosterone (11HT). These steroids are synthesized in testes during full spermatogenesis, and they are excreted in male urine with milt. The third component is not a steroid. It is more likely to be a polyene alcohol (farnesol). 2Z,6E-Farnesol possesses behavioral activity. 相似文献
8.
This paper is a review of microfluidics for particle synthesis from photocrosslinkable materials. Microfluidics for particle synthesis is rapidly gaining attention as a viable method for the synthesis of particles with applications in drug delivery, security, abrasives, rheology, catalysis and other areas. Particle synthesis can follow several schemes, but the focus of this review is particle synthesis from photocrosslinkable materials. In these systems, solid particles are formed by the light-initiated cross-linking of precursor materials. This review begins with a discussion of photocrosslinkable materials, typically synthetic hydrogels for particle synthesis applications. Next, polydimethyl siloxane and glass devices are presented as the primary microfluidic devices for synthesis from photocrosslinkable materials. Then, the review discusses three types of polymeric particles: spherical, spheroidal and Janus. Subsequently, composite particles and metal or metal oxide particles are discussed. The review closes with a discussion of particle throughput and the outlook for the field of particle synthesis from photocrosslinkable materials. 相似文献
9.
Juan Chirinos Jose Arévalo Tamara Rajmankina Angel Morillo Darmenia Ibarra Ali Bahsas Alvaro Parada 《Polymer Bulletin》2004,51(5-6):381-387
Summary The complex
5-(C5H5)2Ti
(1-OC(O)C6H5)2
was synthesized and activated with MA0 for ethylene
polymerization. The resultant polymer is UHMW-PE with a
viscosimetric molecular weight of Mv = 6.8 x
106 to 0.7 x
106 g/mol dependent on the
temperature of the reaction. The effects of the Al/Ti molar
ratio and temperature of the reaction on the catalytic activity
and polymer properties were studied. 相似文献
10.
A glassceramic material, which can be used in stomatology for production of dentinal layer of the dental crown multilayer coating, was received. In order to colour the material the admixtures of Tb and Ce compounds were used, as well as composite admixture representing a mixture of Ce, Nd and La oxides. It was demonstrated that the admixture of Tb oxide tones the material only when it is used together with Ce oxide. It was found that the more admixtures of rare earth elements oxides are contained in the sample composition, the higher the colour strength of the sintered material is. The wave length for the test samples is in the range of 600~650 nm, which corresponds to the yellow-orange and orange-red spectral range. 相似文献