Comparison of emission signals for different polarizations in femtosecond laser-induced breakdown spectroscopy

In this study, a femtosecond laser was focused to ablate brass target and generate plasma emission in air. The influence of lens to sample distance(LTSD) on spectral emission of brass plasma under linearly and circularly polarized pulses with different pulse energies was investigated. The results indicated that the position with the strongest spectral emission moved toward focusing lens with increasing the energy. At the same laser energy, the line emission under circularly polarized pulse was stronger compared with linearly polarized pulse for different LTSDs. Next, electron temperature and density of the plasma were obtained with Cu(Ⅰ) lines,indicating that the electron temperature and density under circularly polarized pulse were higher compared to that under linearly polarized pulse. Therefore, changing the laser polarization is a simple and effective way to improve the spectral emission intensity of femtosecond laserinduced plasma.     

蜗形凸轮的误差分析

运用坐标变换和包络原理对蜗形凸轮进行误差分析,提出了一种加工误差的计算方法,为保证蜗形凸轮的加工精度具有一定的意义。     

非线性阻尼结构系统在随机振动条件下可靠度的估算

阐述了在白噪声特征的稳态随机激励下,两种非线性阻尼结构参数统计的不确定性,分析了它们对系统可靠度估算的影响;运用Ｆｏｋｋｅｒ－Ｐｌａｎｃｋ方程,推导了响应的概率密度函数;可靠度估算中考虑了两种失效机理：即超越门槛值失效和疲劳失效,并采用“两步记忆过程”确定超越概率。结果表明,非线性阻尼对可靠度估算的影响极大．     

悬臂板固有特性几种情况的分析比较

采用两种有限元（矩形板弯元、三角形板弯元）和两种质量矩阵形式（集中质量矩阵、一致质量矩阵）计算等厚度方形悬臂板的固有频率和固有振型，对四种单元／质量矩阵组合形式的固有特性进行了分析比较；指出这些组合形式的数值解与理论解相比产生误差的原因及其改进办法；对变厚度正方形悬臂板（翼面）和等厚度梯形悬臂板（翼面）的固有特性作了启示性分析说明；从中看出不同结构形式悬臂板的固有特性的特点。     

加拿大一枝黄花制浆研究(系列报道之二)碱法蒸煮工艺技术参数的研究

对加拿大一枝黄花碱法蒸煮性能进行了研究。探讨了保温时间、最高温度和用碱量对浆料性能的影响。得到AP法适宜的蒸煮工艺为：用碱量17％（以Na2O计），最高温度160℃下保温120min，其蒸煮结果是：得率49．08％．卡伯值45．4，残碱8．49g／L（以Na2O计）。KP法适宜蒸煮条件为：用碱量17％（以Na2O计），最高温度160℃下保温90min，硫化度20％，其蒸煮结果：得率48．56％，卡伯值28．8，残碱7．32g／L（以Na2O计）。KP法是加拿大一枝黄花较适宜的蒸煮方法。     

发黑工件质量的控制

一、问题的提出 我公司生产的槽筒机产品,有许多工件需进行发黑处理。按常规的操作方法,需对发黑槽液的化学成分进行化验,确定发黑槽液中各介质的含量是否符合配比要求,以便随时对发黑槽液各介质的含量进行调整。但在发黑处理工件的操作过程中,不     

Industrial Internet-enabled Resilient Manufacturing Strategy in the Wake of COVID-19 Pandemic:A Conceptual Framework and Implementations in China

COVID-19 pandemic has accelerated the re-shaping of globalized manufacturing industry.Achieving a high level of resilience is thereby a recognized,essential ability of future manufacturing systems with the advances in smart manufacturing and Industry 4.0.In this work,a conceptual framework for resilient manufacturing strategy enabled by Industrial Internet is proposed.It is elaborated as a four-phase,closed-loop process that centered on proactive industry assessment.Key enabling technologies for the proposed framework are outlined in data acquisition and management,big data analysis,intelligent services,and others.Industrial Internet-enabled implementations in China in response to COVID-19 have then been reviewed and discussed from 3Rs'perspective,i.e.manufacturer capacity Recovery,supply chain Resilience and emergency Response.It is suggested that an industry-specific and comprehen-sive selection coordinated with the guiding policy and supporting regulations should be performed at the national,at least regional level.     

Lower bound capacity based scheduling in MUMIMO system

The current existed scheduling schemes which are generally derived from the antenna selection algorithms can improve the sum-rate of MU-MIMO system to some extent.However,these schemes can not make th...     

C5/C6烷烃异构化机理与催化剂研究进展

为了达到环保要求,使用无铅、低芳烃、低蒸气压、高辛烷值和高氧含量的汽油,降低大气污染是大势所趋。通过C5／C6烷烃异构化生产高辛烷值组分异构化油,改善汽油组成,提高汽油辛烷值的研究和生产工艺得到迅速发展。本文介绍了C5／C6异构化催化反应机理,对国内外C5／C6异构化催化剂研究进行了综述。     

Estimation of thermal coefficients of magneto-optical media

Previously we described a method for estimating the thermal conductivity of magneto-optic recording media. The method relies on identifying the laser power that brings the maximum temperature of the TbFeCo layer to as high as the Curie temperature. We extensively use a similar method to estimate the heat capacity of a dielectric layer, a TbFeCo layer, and an aluminum alloy layer of magneto-optic recording media. Measurements are conducted on static disks with a beam of light focused on a TbFeCo layer. The method has the advantage of thermal diffusion depending on a multilayer structure and irradiation time.