煤与瓦斯突出潜在危险区（带）预测

煤矿的生产和实践证明,发生在矿井中的动力现象具有分区和成带的特点。文章探讨了把煤、岩和瓦斯作为一个体系,采用力学方法的划分问题。根据对煤岩复合样及含瓦斯煤样在复杂应力状态下力学性质的分析,基于对Drucker-prager理论的修正和完善,建立了它们的断裂判据,并给出了计算稳定性系数和潜在弹性应变能密度的公式,提出了按这两个指标划分煤与瓦斯突出潜在危险区（带）的基本方法。     

回旋加速器中的空间电荷效应和束晕(英文)

在考虑束团内粒子之间的空间电荷相互作用力的条件下,对日本理化研究所(RIKEN)现有的一台注入器(加速常数为K70的AVF型回旋加速器)中束团的演变过程进行了模拟计算。模拟结果表明,束团的形变、束晕现象同样发生在回旋加速器中,不过,其产生机制不同于直线加速器。它不是由共振和混沌引起,而是由于粒子的排斥运动和束团内粒子的涡流运动引起的。     

一种解决LED普通照明灯具电气强度测试中拉弧或灯珠失效的方法

针对LED普通照明灯具在电气强度测试过程中,会出现拉弧或灯珠失效的常见现象,对此现象从LED普通照明灯具的常见结构分析,给出了灯具带电部件(基板)距外壳爬电距离的安全值,并从LED本身封装设计特点,对LED基板表面接设旁路安规电容的设计方法,有效的解决了LED普通照明灯具在电气强度测试中拉弧或LED灯珠失效的现象,提高了LED灯具使用寿命,达到了安规标准要求。     

利用脉冲激光对木制品表面抛光技术的研究

介绍了木制品表面的毛刺现象以及去除木制品表面毛刺使木制品表面抛光的重要性。利用脉冲激光对木制品表面进行抛光的技术,最后对脉冲激光使木制品表面抛光技术的发展趋势进行展望。     

加热板液滴蒸发的理论分析及实验研究

液滴蒸发是由气-液浓度差驱动的一种常见而复杂的扩散现象。通过实验与理论相结合对去离子水在玻璃表面和有机硅油表面的蒸发特性进行研究,测量了液滴接触角和接触直径随时间的动态演变过程。结果发现:玻璃表面的液滴蒸发为典型的定底半径模式和混合模式;而液滴在有机硅油表面较为特殊,除了定底半径模式和混合模式还有周期性的黏滑模式。出现黏滑现象是由于实际表面的非光滑性,三相接触线存在摩擦力。当摩擦力最大时,接触角继续减小,液滴接触角增大,三相接触线收缩。     

牵引变流器-电机拍频现象及其抑制方法

交直交传动系统广泛应用于高速铁路牵引领域.由于单相脉冲整流器的工作特性,其输出直流电压含有频率为2倍电网频率的脉动分量.该分量在牵引电机侧会引起拍频现象,尤其当牵引逆变器工作频率接近2倍电网频率时最为严重.首先详细分析了直流电压脉动分量的来源和拍频现象产生的本质.然后,在取消LC谐振电路并考虑直流侧脉动电压幅值和相角变化的情况下,研究了一种基于频率补偿的无拍频控制算法,并应用于间接转子磁场定向矢量控制系统.通过在转速环注入脉动分量,补偿牵引逆变器工作频率,抑制牵引电机拍频电流.最后,仿真结果和硬件在回路实验结果验证了该算法的有效性.     

A Discussion on the Development of SCF-CO2 Hot Embossing Molding Technology and Replication Moldability

This study developed carbon dioxide (CO₂)-assisted hot embossing molding technology using the penetration of SCF (supercritical fluid), as generated by CO₂ in a high pressure process, into the high polymer plastic substrate in order to realize the plasticization phenomenon. At the glass transition temperature (Tg), microstructure array elements were molded by hot embossing replication, and the optical effects of the formed microstructure were discussed. This study first developed the SCF hot embossing system equipment by evenly infiltrating the plastic substrate through the SCF phenomenon generated by CO₂ under high pressure. Using the characteristics of the CO₂-aided uniform imprinting technology, this study discussed the microstructure replication moldability and optical effects of the microstructure at the Tg temperature. The results suggested that the SCF hot embossing system proposed in this study can successfully transliterate the microstructure onto the photo-resist at Tg temperature. This study also tested and discussed the replication moldability and optical effects of the structure.     

The inverse hockey stick effect: an empirical investigation of the fiscal calendar’s impact on firm inventories

We empirically investigate how manufacturers’ inventory decisions relate to the fiscal calendar. Although optimal firm inventories should depend on demand and supply, we find that the artificial accounting construct of the fiscal year frequently drives inventory dynamics. In an effort to manage earnings and cash flows (CFs) towards the fiscal year-end (FYE), firms significantly reduce their inventories in the fourth fiscal quarter only to increase their inventories in the next fiscal year. Using a sample of 4877 US manufacturing firms for the period 1990–2010, we find that inventories are 3.9–6.0% lower on average in the fourth fiscal quarter. In the analysis, we control for inventory theory-related factors that have been identified in prior literature. Because this pattern is the inverse of that observed for sales, we refer to this phenomenon as the inverse hockey stick effect. The effect holds for all three individual inventory types: raw materials, work in progress and finished goods. We find that inventory reductions in the fourth fiscal quarter are particularly substantial if firms have an incentive to beat CF targets. In contrast to our expectations, we do not find evidence that financial distress links to inventory reductions at the FYE.     

集装箱起重设备编码器故障及排除

阐述了集装箱装卸起重设备中编码器的作用和重要性,从排除编码器故障实例中,总结编码器使用中常出现的几种故障及排除方法。     

Quantitative conditions for the formation of p-wave neutron halos

With the experimental binding energies and configurations, the root-mean-square radii of p-wave valence neutron distributions for nuclei up to the second p-shell have been calculated in the framework of the single-particle potential model. By analyzing th