危险化学品管理现状及其分类的一般程序

文章首先对目前国内外化学品管理的现状进行了综述,然后阐述了化学危险品分类的判据以及危险品分类的一般程序,最后还说明了危险品分类的注意事项.     

NiTi合金表面镀类金刚石薄膜的生物摩擦学性能研究

用脉冲电弧离子镀在镍钛合金基底上沉积了无氢类金刚石(DLC)薄膜,研究和评价了镀膜样片的体外生物摩擦学特性.结果表明,在干摩擦及润滑条件下,DLC薄膜的体积磨损率仅为NiTi合金的3%～7%,有很好的抗磨损能力.DLC薄膜的减摩效果也很明显,干摩擦条件下最大,达到80%以上,润滑条件下也都达到了70%以上.     

低压氧液化流程与中压氧液化流程的比较

简单介绍了现有钢厂用液化设备流程的分类 ,主要从液化流程本身的特点和降低液化装置能耗两方面来探讨低压氧液化流程和中压氧液化流程。     

Electrical properties of Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics modified with WO3

Ferroelectrics 0.67Pb (Mg_1/3Nb_2/3)O₃-0.33PbTiO₃ (PMN-PT) + x mol% WO₃ (x=0.1, 0.5, 1, 2) were prepared by columbite precursor method. Electrical properties of WO₃-modified ferroelectrics were investigated. X-ray diffraction (XRD) was used to identify crystal structure, and pyrochlore phase were observed in 0.67Pb (Mg_1/3Nb_2/3)O₃-0.33PbTiO₃+2 mol% WO₃. Dielectric peak temperature decreased with WO₃ doping, indicating that W⁶⁺ incorporated into PMN-PT lattice. Lattice constant, pyrochlore phase and grain size contribute to the variation of K_max. Both piezoelectric constant (d₃₃) and electromechanical coupling factors (k_p) were enhanced by doping 0.1 mol% WO₃, which results from the introduction of “soft” characteristics into PMN-PT, while further WO₃ addition was detrimental. We consider that the two factors, introduction of “soft” characteristics and the formation of pyrochlore phase, appear to act together to cause the variation of piezoelectric properties of 0.67PMN-0.33PT ceramics doping with WO₃.     

Rapid fabrication and optical properties of zinc sulfide nanocrystallines in a heterogeneous system

ZnS nanoparticles about 3 nm in size were prepared by a simple, rapid and reliable route under microwave irradiation in a heterogeneous system, using ZnAc₂·2H₂O (AcCH₃COO) and Na₂S·9H₂O as the starting materials, ethylene glycol (EG) as the medium. The product was characterized with X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and ED, respectively. The optical properties of ZnS nanoparticles were studied.     

柔性生产线工艺设计

以别克仪表生产线的平面布置设计为例 ,叙述柔性生产线工艺设计的整个过程 ,以达到用最少的加工设备、最少的人员配置满足顾客的需求     

调质状态下 4 0 C r钢的焊接

在合理制定焊接工艺的基础上,采用R307珠光体耐热钢焊条成功地进行了40Cr钢在调质状态下的焊接,解决了通常采用25-13型奥氏体焊条焊接时出现的焊缝强度低、焊接接头性能差的问题。     

模拟退火算法的改进及其在电机电磁场逆问题数值计算中的应用

在对制约模拟退火（ＳＡ）算法收敛速度的若干问题研究的基础上,本文构造了改进的ＳＡ算法。通过应用于大型水轮发电机极靴形状优化设计中电磁场逆问题的数值计算,以及与国外样机数据和其他优化算法计算结果的对比分析,验证了本算法的有效性和正确性。     

130 t钢包底吹氩喷嘴布置模式优化的水模型试验

通过建立的130t钢包水力学模型，用电导法测定了单喷嘴、双喷嘴垂直分布和对称分布时不同供气量下钢水混匀时间。结果表明，双喷嘴喷吹的混匀时间较单喷嘴的混匀时间短，搅拌效果优于单喷嘴。单喷嘴底吹氩，喷嘴距钢包底部中心0．55R（钢包底半径）时混匀时间最短；双喷嘴间距由0．40R增至0．70R时混匀时间明显减少。     

KThin-YOLOV7:轻量级的焊接件表面缺陷检测

针对目前市面主流焊接件表面缺陷的模型检测精度不高,模型复杂和不满足实时监测等问题,提出了一种基于YOLOV7-tiny改进得到的焊接件表面缺陷新型检测模型KThin-YOLOV7。首先,设计了基于模拟人类视觉感受野的EMA-BasicRFBC模块,更换YOLOV7-tiny模型的空间特征金字塔SPP模块,从而加强模型特征表达的性能。其次,以SlimNeck设计范式结构为基础设计了ThinNeck结构,并用其更换YOLOV7-tiny的NECK特征融合部分,减少模型的参数量和计算量的同时提高了模型的平均检测精度。最后,引入K-means++算法找出合适的锚框,并用FEIOU损失函数更换原模型的LOSS,进一步帮助模型优化目标框的位置和大小。KThin-YOLOV7相对原始YOLOV7-tiny模型的mAP提升了7.11％,达到87.64％,同时模型的参数量和计算量分别下降了11.14％和15.26％。实验结果表明,KThin-YOLOV7能够高效且准确地定位检测焊接件表面的缺陷。