中国光纤光缆产业的发展趋势探讨

本文通过回顾我国光纤光缆产业的关键技术和产业构成,分析总结产业发展取得的成果和存在的不足,提出了我国光纤光缆产业下一步发展的五个方向的思考,供同行们参考。     

城市雨水口设计的探讨

在城市雨水排放系统中,设置合理的雨水口可以使雨水迅速排入雨水管网,避免积水产生。分别从雨水口的位置和长直路面雨水口设置间距2个方面介绍了城市雨水口的设置。     

短历时暴雨袭击致早龄期混凝土温度裂缝研究

早龄期混凝土表面开裂是工程中普遍存在的问题。模拟了某拱坝17号坝段混凝土在短历时暴雨袭击下的温度变化,分析了336.5 m高程裂缝产生的主要原因,并且讨论了其在有无保温养护条件下混凝土的温度变化和温度应力情况。计算结果表明,短历时暴雨引起的气温骤降和混凝土表面放热系数增大,是该表面裂缝产生的主要原因;做好表面保温养护工作可有效防止混凝土开裂,对后期大坝安全运行具有重要意义。     

OMG脱墨过程中Zeta电位及表面张力的变化

本文主要探讨了美国彩色废旧杂志纸(OMG)在脱墨处理时,浆料分散体系的胶体化学行为如Zeta电位、表面张力的变化与脱墨效果的关系,并对影响胶体化学行为的工艺条件进行了分析研究.实验证明,在一定范围内改变OMG脱墨分散体系胶体化学行为,有助于进一步去除油墨粒子,提高脱墨浆质量.     

对称密钥加密算法在IPsec协议中的应用

IPsec协议是互联网中最重要的协议之一,也是多年来用以解决网络安全问题的技术,在路由器、防火墙等设备中有着广泛的应用,同时在各种软件系统中也扮演重要角色。通过对IPsec协议中加密算法的讨论,重点分析了对称密钥加密算法在ESP中的应用,包括DES、3DES、IDEA、AES、SM4等加密算法。分析了各个算法实现的特点、复杂度和安全强度,对比了算法在软硬件平台实现所需资源以及实现速度,为IPsec协议设计应用时提出了建议,能有针对性的使用对称密钥加密算法,合理有效的解决安全方案。     

Method for solving the nonlinear inverse problem in gas face seal diagnosis based on surrogate models

Physical models carry quantitative and explainable expert knowledge. However, they have not been introduced into gas face seal diagnosis tasks because of the unacceptable computational cost of inferring the input fault parameters for the observed output or solving the inverse problem of the physical model. The presented work develops a surrogate-model-assisted method for solving the nonlinear inverse problem in limited physical model evaluations. The method prepares a small initial database on sites generated with a Latin hypercube design and then performs an iterative routine that benefits from the rapidity of the surrogate models and the reliability of the physical model. The method is validated on simulated and experimental cases. Results demonstrate that the method can effectively identify the parameters that induce the abnormal signal output with limited physical model evaluations. The presented work provides a quantitative, explainable, and feasible approach for identifying the cause of gas face seal contact. It is also applicable to mechanical devices that face similar difficulties.     

水杨酸体系抛光液中钌的化学机械抛光研究

研究了抛光液中H2O2和水杨酸浓度对钌的抛光速率的影响。采用电化学方法和X射线光电子能谱分析了H2O2和水杨酸对金属钌腐蚀效果的影响;采用原子力显微镜观察钌表面的微观形貌。结果表明:水杨酸浓度的增加有利于金属钌表面钝化膜的形成,抛光速率值随之增加;随着H2O2浓度的不断增加,抛光速率不断增加,当H2O2质量分数大于3%时,抛光速率值随浓度的增加而降低。抛光后的金属钌表面平均粗糙度Ra为7.2 nm。     

机器人灵活性表示及冶钢-弧焊-Ⅰ型工业机器人工作空间灵活度分析

本文提出了用机器人操作器末杆的自转角灵活度及两个互相垂直的主截面内的灵活度的组合,来表示机器人对给定工作点的灵活性的方法。这种方法直观、方便,易于求解和应用.用它研究具有结构条件限制的机器人操作器工作空间灵活度时,发现在工作空间里,存在有不同灵活度的区域,曲线或曲面.本文还特别提出了工具(夹具)的预置位姿的概念,并以 5R 操作器为例,充分证明了预置位姿的改变.可以在操作器灵活度不变的条件下大大改善机器人的工作可能性。     

Porous SnIn4S8 microspheres in a new polymorph that promotes dyes degradation under visible light irradiation

Porous SnIn(4)S(8) microspheres were initially synthesized through a facile solvothermal approach and were investigated as visible-light driven photocatalysts for dyes degradation in polluted water. The photocatalysts were characterized by XRD, SEM, TEM, N(2) adsorption-desorption, and UV-vis diffuse reflectance techniques. Results demonstrated that the as-synthesized SnIn(4)S(8) was of a new tetragonal polymorph, showing a band-gap of 2.5 eV, a specific surface area of 197 m(2) g(-1), and an accessible porous structure as well. The photocatalytic activity of the porous SnIn(4)S(8) was evaluated by decomposition of several typical organic dyes including methyl orange, rhodamine B, and methylene blue in aqueous solution under visible light irradiation. It is demonstrated that porous SnIn(4)S(8) was highly photoactive and stable for dyes degradation, showing photocatalytic activity much higher than binary constituent sulfides like In(2)S(3), SnS(2), or even ternary chalcogenide ZnIn(2)S(4) photocatalyst. The excellent photocatalytic performance of porous SnIn(4)S(8) is the consequence of its high surface area, well-defined porous texture, and large amount of hydroxyl radicals.     

岩爆的相似材料物理模拟研究

 根据不同配合比相似材料的物理力学性质测试结果,选取最具岩爆倾向的相似材料,结合一水电站引水隧洞典型断面,制作大尺寸模型,采取后开孔的隧洞成洞方式进行岩爆物理模拟试验研究。结果表明：在模型的边界条件保持工程区天然应力状态下,隧洞开挖过程中拱顶、拱肩和边墙部位在不同的时间段内分别有较明显的应力、应变突变现象,围岩声发射次数也表现出剧烈增大现象,说明围岩出现明显的岩爆表征。模型在超载条件下出现围岩剥落、鼓折和开裂现象,表明原型隧道段以剥落、鼓折式张性岩爆为主。