十二烷基硫酸钠改性氢氧化镁阻燃剂的实验研究

氢氧化镁具有阻燃、消烟、填充多种功能,是一种重要的无机环保型阻燃材料。实验采用十二烷基硫酸钠对氢氧化镁阻燃剂进行了湿法表面改性研究,对改性前后的氢氧化镁粉体进行了黏度、吸油值、堆积密度及红外光谱等表面物化性能表征,从而确定最佳的表面改性工艺条件。实验结果表明：对氢氧化镁的最佳改性时间为60 m in,改性温度为90℃,改性剂用量为2%。改性前后氢氧化镁粉体红外光谱图的对比分析显示氢氧化镁表面有新的化学键形成。     

胶黏剂剪切强度影响因素的研究

胶黏剂作为一种新型的连接材料在国民经济的各个领域应用越来越广泛。胶黏剂的剪切强度与黏接过程中形成的化学键等作用力以及胶黏剂本身的结构有关,同时还与胶接材料表面状况、胶接工艺等因素有密切联系。主要研究了胶接材料的表面处理方法、漂洗水温、胶层厚度、胶液稳定性等因素对胶黏剂剪切强度的影响。     

硬脂酸镁改性氢氧化镁阻燃剂的实验研究

采用硬脂酸镁对氢氧化镁进行湿法表面改性,考察了硬脂酸镁用量、改性温度及改性时间对改性效果的影响。通过改性前后氢氧化镁阻燃剂粉体的活化指数、吸油值及其在分散介质(液体石蜡)中的黏度等表面物化性能来评价氢氧化镁的改性效果,从而确定最佳改性条件,同时采用红外谱图研究了硬脂酸镁与氢氧化镁表面的作用机理。实验结果表明,在硬脂酸镁用量为3%,改性温度为90℃,改性时间为40min的条件下制备的产品性能优良,活化指数达99.4%,吸油值由改性前的78.6%降至40%,黏度较改性前明显降低,硬脂酸镁分子在氢氧化镁表面发生化学吸附键合。     

粗糙表面电磁散射系数数字方法分析与比较

回顾了随机粗糙表面电磁散射特性计算方法的特点,分析对比了各类积分方程法和微分方程法的核心算法,着重讨论了矩阵分裂算法的计算效率,以及时域有限差分法求解色散粗糙面宽带散射特性的有关问题,指出了粗糙表面散射系数的计算和选择方法。     

倒边盖挖逆作法基坑支护结构可靠性分析

为了解决采用标准Monte Carlo法计算复杂基坑工程上常见小概率失效,导致计算效率低的问题,以南京市湖南路地下商业街工程为工程背景,首先,将随机响应面法与基坑工程三维模型相结合,求解极限功能函数的响应面方程,并用标准Monte Carlo法计算失效概率和可靠指标,探讨采用倒边盖挖逆作法作为基坑支护结构施工方法的可行性;其次,基于该响应面方程,以土体的弹性模量为随机变量参数,采用马尔可夫链蒙特卡罗子集模拟法(MCMC子集模拟法)计算基坑支护结构的失效概率,并与标准Monte Carlo法结果进行对比分析。结果表明：当支护结构最大侧移控制指标为25 mm时,计算得到的可靠指标均大于4.6,即采用倒边盖挖逆作法施工过程中基坑是安全的;10万次和50万次标准Monte Carlo法计算得到的失效概率均为零,说明对于标准Monte Carlo法,在计算小概率失效问题时10万与50万的样本量是不足的;而MCMC子集模拟法用2.98万个样本计算出的结果与标准Monte Carlo法采用100万个样本计算的结果相对误差仅为1.7%,表明MCMC子集模拟法对于小概率失效问题求解的优势。所提算法在一定...     

基于响应面法的换流变压器励磁涌流峰值快速计算分析

为解决传统数值法和软件仿真法求解变压器励磁涌流存在模型参数固定、效率低下等问题,提出将响应面拟合计算方法运用在换流变励磁涌流的计算中,实现考虑到主心柱在不同剩磁的条件下的励磁涌流峰值随合闸角变化的高效计算分析。理论分析变压器励磁涌流的产生机理,提取出关键影响因素,采用参数建模建立换流变压器模型,通过响应面试验设计拟合绕组初始电流、合闸角和励磁涌流峰值之间的响应面模型,并验证响应面的精度。研究成果可为变压器励磁涌流快速计算分析、电力变压器数字孪生技术提供技术参考。     

Machine learning for quantitative finance: fast derivative pricing,hedging and fitting

In this paper, we show how we can deploy machine learning techniques in the context of traditional quant problems. We illustrate that for many classical problems, we can arrive at speed-ups of several orders of magnitude by deploying machine learning techniques based on Gaussian process regression. The price we have to pay for this extra speed is some loss of accuracy. However, we show that this reduced accuracy is often well within reasonable limits and hence very acceptable from a practical point of view. The concrete examples concern fitting and estimation. In the fitting context, we fit sophisticated Greek profiles and summarize implied volatility surfaces. In the estimation context, we reduce computation times for the calculation of vanilla option values under advanced models, the pricing of American options and the pricing of exotic options under models beyond the Black–Scholes setting.     

An examination of the congruence and incongruence between employee actual and customer perceived emotional labor

This study examines the effects of the congruence and incongruence between employee actual and customer perceived emotional labor on customer trust. Based on data collected from 510 service employee and customer dyads in restaurants, the results of response surface modeling indicate that customer trust is higher when employee deep acting and customer perceived deep acting are both high rather than both low. Customer trust is also higher when customer perceived deep acting is higher than employee actual deep acting rather than vice versa. The effects are different in surface acting: as employee surface acting and customer perceived surface acting increase, customer trust initially decreases, then increases, exhibiting a U‐shaped effect. Implications for both theory and practice are discussed.     

Perceptual Density of Guava Juice: The Effect of Image Location and Surface Texture

Guava is known for its rough (astringent) appearance and texture; feature attached to its nutritional benefits but rejected from consumers’ point of view. This study deals with the rough property of guava juice through packaging expecting to influence its perceived density. Two studies were designed by manipulating (a) the location of the image on the bottle and (b) the surface texture of the bottle, controlling for transparency. Results confirm that it is possible to shift the perception of density in guava juice (a) locating the image of the fruit on the top (not the bottom) of the bottle and (b) using a smooth surface texture (not a rough) on an opaque bottle. Concerning practical implications, agribusinesses should enforce the use of sensory marketing strategies to sell the best of fruits and vegetables.     

员工-配偶工作家庭边界分割偏好匹配对员工工作投入的影响机制研究

依据个体-环境匹配理论和平衡理论，基于320份员工与配偶的配对问卷调查数据，采用多元回归分析、响应面分析以及块变量分析方法，探讨了员工-配偶工作家庭边界分割偏好不同匹配/不匹配类型对员工工作投入及情感平衡的影响。结果表明：员工-配偶工作家庭边界分割偏好匹配有利于提高员工的情感平衡和工作投入水平；而员工-配偶工作家庭边界分割偏好不匹配则会降低员工的情感平衡和工作投入水平。具体而言，当员工-配偶工作家庭边界分割偏好匹配时，员工边界分割偏好高-配偶边界分割偏好高对员工情感平衡和工作投入的正向影响更强；当员工-配偶工作家庭边界分割偏好不匹配时，员工边界分割偏好低-配偶边界分割偏好高对员工情感平衡和工作投入的负向影响更强。无论员工-配偶工作家庭边界分割偏好是否匹配，情感平衡均在其对员工工作投入的影响中起中介作用。