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91.
研究了促进剂的种类,促进剂并用及硫化温度等条件对平衡硫化体系(EC)硫化天然橡胶(NR)的影响。结果表明,噻唑类促进剂具有较低的硫化返原率,尤其是促进剂DM,在130~170℃的硫化温度范围内,硫化2小时的硫化返原率均为0;当促进剂NOBS或CZ与DM并用时,可缩短正硫化时间;当DM摩尔分数分别为40%和50%左右时,不仅使硫化2小时的硫化返原率为0,而且可使300%定伸应力保持恒定;以NOBS或CZ为主促进剂时,正硫化时具有较高的拉伸强度和撕裂强度,但硫化2小时时的降低幅度比DM大。 相似文献
92.
采用主监视窗扩展技术的增强现实三维注册方法 总被引:1,自引:0,他引:1
在增强现实三维注册中,采用重新检测策略时顿卡现象严重。提出一种采用主监视窗扩展技术的增强现实三维注册方法。在检测阶段,引入特征点可信度和主监视窗,并设计主监视窗的分割、扩展和调控策略,大幅提升了计算速度;在跟踪阶段,采用基于图像金字塔的光流算法进行特征点跟踪。实验证明,该方法不仅有效缓解了顿卡现象,也提升了系统整体的实时性。 相似文献
93.
M. Ghiaci R. Kia A. Abbaspur F. Seyedeyn-Azad 《Separation and Purification Technology》2004,40(3):285-295
Synthetic and natural zeolites, modified by the quaternary amines, i.e. hexadecyltrimethylammonium (HDTMA) bromide and n-cetylpyridinium bromide (CPB) as well as MCM-41 molecular sieve were employed for removal of chromate from aqueous solution. Obtained data from chromate adsorption experiments over the mentioned materials were compared. It was shown that adsorption data for modified zeolite using the amine was consistent with Langmuir isotherm equation. The maximum chromate adsorption over as synthesized MCM-41 was much greater than that of the natural clinoptilolite and ZSM-5 zeolites. 相似文献
94.
Tae?Joon?Chung Min?Chan?Kim Chang?Kyun?ChoiEmail author 《Korean Journal of Chemical Engineering》2004,21(1):41-47
The temporal development of thermal disturbances in the fluid layer heated isothermally from below is investigated, based
on propagation theory. This theory is examined by using scaling. To examine the behavior of thermal instability the mean-field
approximation is employed and resulting equations are solved by Galerkin method. The stability criteria to mark the onset
of convective instability are newly suggested as the intersection point of the growth rate of averaged temperature with that
of its fluctuation. The resulting critical time is close to that derived from propagation theory. By considering the nonlinear
effects, the characteristic times to represent the detection time of manifest convection and also to exhibit the minimum Nusselt
number are discussed. 相似文献
95.
96.
Desislava Bögner Frederike Schmachtl Björn Mayr Christopher P. Franz Sabine Strieben Gregor Jaehne 《臭氧:科学与工程》2019,41(2):105-117
Recirculating Aquaculture Systems (RAS) reduce water consumption by efficient filtration to maintain appropriate levels of accumulating compounds and sludge. Sludge is mechanically separated by drum filters and disposed of to the detriment of overall system water budgets. Dissolved nitrogen compounds are reduced via nitrification–denitrification filters, requiring commercial external carbon sources. The reuse of sludge after ozone pre-treatment may represent the next step in RAS optimization. The present study analyzes the content of sludge from RAS and tests ozonation as a pre-treatment for recycling as carbon source. The dissociative effect of ozone and the physicochemical changes due to ozonation lead to a significant increase in soluble carbon availability. Predominantly long-chain fatty acid (FA) (saturated and unsaturated) with 16 and 18 carbon atoms independently of the treatment were found in the profiles. Saturated FA concentrations in solution increased after 20, 40, and 60 min ozonation. The solid content of the sludge was practically unaffected by ozonation in terms of FA profile: only saturated FA slightly increases after 40 min treatment. The implications of these findings for denitrifying bacteria are discussed.
Abbreviations: Recirculating Aquaculture Systems (RAS); Advanced Oxidation Processes (AOPs) 相似文献
97.
Ghada Al‐Bandak Vassiliki Oreopoulou 《European Journal of Lipid Science and Technology》2007,109(3):247-255
Majorana syriaca is an important food‐flavouring ingredient in the Middle Eastern culture known commonly as Za'atar. The components of the plant were extracted in a Soxhlet apparatus sequentially with solvents of increasing polarity, specifically with petroleum ether (P), diethyl ether (D), ethyl acetate (EAc), and ethanol (E). The activity of the extracts to scavenge the 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH?) followed the order D > E > EAc > P. Moreover, the antioxidant activity in corn oil at concentrations of 200, 500 and 1000 ppm was monitored through peroxide value and conjugated hydroperoxide measurements and revealed that D and E extracts resulted in the highest protection followed by EAc and P extracts. Increasing the concentration from 200 to 500 ppm depressed peroxide formation, while a further increase had no effect. The main components of the P extract according to GS‐MS analysis were thymol (42.89%) and carvacrol (42.75%). The remaining extracts comprise flavonoids and phenolic acids that provide the antiradical and antioxidant activity. 相似文献
98.
99.
The inverse problem approach by conjugate gradient with adjoint equations is adapted to the context of a non-isothermal bioprocess, controlled by internal heat generation from microbial oxidation, as could be found in a composting reactor for instance, to determine the heat source from internal temperature measurements. The volumetric heat source is assumed proportional to the rate of consumption of a substrate by a biomass, as described by a Monod model. Computations are performed for Rayleigh numbers equal to 0.25 and 25, for a representative biochemical reaction under typical boundary conditions, for constant and temperature-dependent model parameters. The influence of noisy input data is also considered. It is found that good solutions can be obtained when heat release and diffusion occur over very different time scales. The variation of the model parameters with temperature must be taken into account, but single sensor solutions are possible at relatively small Rayleigh numbers when convection is present. 相似文献
100.
In this work, magnesia from natural brucite mineral has been used firstly for catalytic degradation of nitrobenzene and aniline
in presence of ozone. Compared with single ozonation, the catalytic ozonation accelerated markedly the degradation of nitrobenzene
and aniline. The influences of hydroxyl radical scavengers, pH values, and reaction temperatures on degradation were investigated.
It was found that the essential of catalysis was the homogeneous catalysis of hydroxyl ions in water, which accelerated the
generation of hydroxyl radicals. As a catalyst, magnesia from natural brucite has supplied an economical and feasible choice
for catalytic ozonation of nitrobenzene and aniline in industrial wastewater. 相似文献