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1.
纸浆绿色漂白技术新进展   总被引:6,自引:4,他引:2       下载免费PDF全文
回顾了国内外纸浆绿色漂白技术的现状,主要介绍了H2O2漂白、臭氧漂白、生物漂白、电化学漂白以及其他漂白技术的新进展。  相似文献   
2.
We present a large class of nonlinear models of European options as parabolic equations with quasi-linear diffusion and fully nonlinear hyperbolic part. The main idea of the operator splitting method (OSM) is to couple known difference schemes for nonlinear hyperbolic equations with other ones for quasi-linear parabolic equations. We use flux limiter techniques, explicit–implicit difference schemes, Richardson extrapolation, etc. Theoretical analysis for illiquid market model is given. The numerical experiments show second-order accuracy for the numerical solution (the price) and Greeks Delta and Gamma, positivity and monotonicity preserving properties of the approximations.  相似文献   
3.
<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586  相似文献   
4.
稀土永磁电机由于其高效、高功率密度的特点,在轨道交通牵引系统的设计中受到了广泛和密切的关注。由于其全封闭式结构,牵引电动机的负载能力主要受限于冷却系统的散热能力。建立了一台永磁牵引电动机的全封闭式自循环空-空冷却系统,通过对参数散热敏感性的分析,确定了适宜的冷却结构参数范围。针对该冷却结构,应用有限公式法进行三维温度场数值计算,确定了散热系统的结构参数,并用流固耦合仿真验算了计算结果。  相似文献   
5.
为了在不增加计算复杂度的前提下,构造既具有凸包性,又具有保形性的类3次均匀B样条曲线。首先采用逆向思维法,通过预设的曲线性质来反推调配函数的性质,进而计算出调配函数的表达式。然后采用定性分析法,分别讨论当曲线具备凸包性、保单调性、保凸性、变差缩减性时,曲线中参数的取值范围,文中图例显示了分析结果的正确性。不同情况下所得参数取值范围的交集,即为最终确定的曲线中形状参数的可行域,在可行域内改变形状参数,可以在不破坏曲线保形性的前提下调整曲线对控制多边形的逼近程度。简要讨论了与曲线对应的张量积曲面,并给出了图例。  相似文献   
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ABSTRACT

In this paper, the problem of finite-time stability and stabilisation for positive singular discrete-time linear systems with time-varying delay is investigated. We first present novel delay-dependent sufficient conditions for positivity and finite-time stability of the unforced systems. We then apply the obtained results to solve finite-time stabilisation problem of the considered systems. The sufficient conditions for the positivity and finite-time stabilisable of such systems are formulated in terms of a standard linear programming (LP) problem. Numerical examples are provided to illustrate the effectiveness and advantages of our results.  相似文献   
8.
首先运用两种方法构造了带多形状参数的C^3连续的插值曲线.其次,利用方法二把构造出的带多形状参数的C^4连续的B样条曲线与参数化的奇异多边形按某个因子调配,可自动生成C^4连续的插值曲线.所有这些曲线的形状既能整体又可局部调控.  相似文献   
9.
Emotion theorists have long debated whether valence, which ranges from pleasant to unpleasant states, is an irreducible aspect of the experience of emotion or whether positivity and negativity are separable in experience. If valence is irreducible, it follows that people cannot feel happy and sad at the same time. Conversely, if positivity and negativity are separable, people may be able to experience such mixed emotions. The authors tested several alternative interpretations for prior evidence that happiness and sadness can co-occur in bittersweet situations (i.e., those containing both pleasant and unpleasant aspects). One possibility is that subjects who reported mixed emotions merely vacillated between happiness and sadness. The authors tested this hypothesis in Studies 1–3 by asking subjects to complete online continuous measures of happiness and sadness. Subjects reported more simultaneously mixed emotions during a bittersweet film clip than during a control clip. Another possibility is that subjects in earlier studies reported mixed emotions only because they were explicitly asked whether they felt happy and sad. The authors tested this hypothesis in Studies 4–6 with open-ended measures of emotion. Subjects were more likely to report mixed emotions after the bittersweet clip than the control clip. Both patterns occurred even when subjects were told that they were not expected to report mixed emotions (Studies 2 and 5) and among subjects who did not previously believe that people could simultaneously feel happy and sad (Studies 3 and 6). These results provide further evidence that positivity and negativity are separable in experience. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
10.
Previous studies reveal age by valence interactions in attention and memory, such that older adults focus relatively more on positive and relatively less on negative stimuli than younger adults. In the current study, eyeblink startle response was used to measure differences in emotional reactivity to images that were equally arousing to both age groups. Viewing positive and negative pictures from the International Affective Picture System had opposite effects on startle modulation for older and younger adults. Younger adults showed the typical startle blink pattern, with potentiated startle when viewing negative pictures compared to positive pictures. Older adults, on the other hand, showed the opposite pattern, with potentiated startle when viewing positive pictures compared to viewing negative and neutral pictures. Potential underlying mechanisms for this interaction are evaluated. This pattern suggests that, compared with younger adults, older adults are more likely to spontaneously suppress responses to negative stimuli and process positive stimuli more deeply. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
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