304不锈钢薄壁环类零件的车削加工

介绍不锈钢材料薄壁环类零件切削加工的特点,总结实际切削加工中出现的不良现象并浅析其原因,针对这类零件具有的韧性高、导热性差、高温硬度高、切削黏附性强、易于加工硬化与切削变形等不利因素,基于工件装夹、刀具材料及参数、切削用量、冷却润滑等方面,总结出了1套加工方案。实践表明,此方案能延长刀具的使用寿命,保证零件的加工质量,提高生产效率,降低刀具损耗,节能减排。其采用的冷却方式环保,近乎于清洁生产。     

气溶胶细粒子与能见度的相关性研究

为了分析气溶胶粒子特别是细粒子（PM2.5）对能见度的影响,本文从理论上建立了气溶胶细粒子与能见度的关系,分析了谱分布、PM2.5/PM10和细粒子消光所占总消光比重的关系。利用2004年8月在北京的测量数据与理论计算对比表明：建立的气溶胶细粒子与能见度的关系是合理的。这对治理污染提高城市能见度是很有指导意义的。     

Uncoupling tumor necrosis factor-α and interleukin-10 at tumor immune microenvironment of breast cancer through miR-17-5p/MALAT-1/H19 circuit

Triple Negative Breast Cancer (TNBC) immunotherapy has recently shown promising approach. However, some TNBC patients presented with resistance. One of the reasons was attributed to the excessive release of cytokines at the tumor microenvironment (TME) such as Tumor necrosis factor alpha (TNF-α) and Interleukin-10 (IL-10). Fine regulation of these cytokines’ levels via non-coding RNAs (ncRNAs) might alleviate the immune quiescent nature of TME at TNBC tumors. However, the extrapolation of ncRNAs as therapeutic tools is highly challenging. Therefore, disentanglement the nature for the isolation of natural compounds that could modulate the ncRNAs and their respective targets is an applicable translational therapeutic approach. Hence, this study aimed to targeting the chief immune suppressive cytokines at the TME (TNF-α and IL-10) via ncRNAs and to examine the effects of Rosemary aerial parts extract on the expression levels of these ncRNAs in TNBC. Results revealed miR-17-5p as a dual regulator of TNF-α and IL-10. Moreover, an intricate interaction has been shown between miR-17-5p and the oncogenic lncRNAs: MALAT1 and H19. Knocking down of MALAT1 and/or H19 caused an induction in miR-17-5p and reduction in TNF-α and IL-10 expression levels. miR-17-5p was found to be down-regulated, while TNF-α, IL-10, MALAT1 and H19 were up-regulated in BC patients. Forced expression of miR-17-5p in MDA-MB-231 cells reduced TNF-α, IL-10, MALAT1 and H19 expression levels, as well as several BC hallmarks. In a translational approach, ursolic acid (UA) isolated from rosemary induced the expression of miR-17-5p, MALAT1 and decreased H19 expression levels. In conclusion, this study suggests miR-17-5p as a tumor suppressor and an immune-activator miRNA in BC through tuning up the immunological targets TNF-α, IL-10 at the TME and the oncological mediators MALAT1 and H19 lncRNAs.     

激光选区熔化3D打印AlSi10Mg合金的铺粉厚度

基于铺粉厚度优选出的3个工艺参数组合,分析了工艺参数组合对激光选区熔化技术成形AlSi10Mg合金试样基本性能的影响。3个工艺参数组合成形的试样硬度均高于63HRB,上表面单位面积磨损量均低于1.5×10-5 g/(s·mm2),孔隙率在0.05%以下,抗拉强度高于440 MPa,成形的测试试样尺寸误差均在±0.1 mm以内。试样上表面的表面粗糙度Ra在4 μm以下,侧表面的表面粗糙度Ra在5 μm以下。铺粉厚度30 μm的试样表面质量最优。     

Fluorescence of complexes of EuⅢwith aromatic carboxylic acid-1,10-phenanthroline

Fluorescence of complexes of EuⅢwith aromatic carboxylic acid-1,10-phenanthroline@舒万艮 @周忠诚 @牛聪伟~~     

柴油机实现超低排放的应对策略

从柴油机排放的主要污染物PM和NOX的生成机理出发,提出了实现柴油机超低排放的对应策略。     

颗粒致密度对WC-10Co-4Cr涂层性能的影响

利用超声速火焰喷涂技术(High velocity oxygen fuel,HVOF)并采用两种不同颗粒致密度的WC- 10Co-4Cr合金粉末在300M钢表面制备涂层.采用扫描电镜、X射线衍射仪、显微硬度计等设备对两种涂层的微观组织结构及特性进行分析,重点研究碳化钨颗粒的沉积过程,并通过腐蚀电化学试验研究两种涂层的耐...     

D-STATCOM硬件电路PCB板设计与制作

首先介绍了三相四线制D．STATCOM的主要结构,电流检测算法和电流跟踪控制方法,在以上方法基础上,利用Multisim 10和Protel DXP 2004对D—STATCOM硬件电路进行设计和仿真,并利用Protel DXP 2004得到所设计的PCB板,为D-STATCOM在实际电力系统中投入使用奠定基础。     

不同晶型SiC_p对铜基粉末冶金摩擦材料摩擦磨损性能的影响

采用加压烧结法制备含有不同晶型SiCp的铜基粉末冶金摩擦材料,研究不同晶型SiCp对铜基粉末冶金摩擦材料摩擦磨损性能的影响。结果表明:不同晶型SiCp对铜基粉末冶金摩擦材料的摩擦磨损性能的影响不同。摩擦材料的摩擦因数随着β-SiCp加入量的增加而升高,当β-SiCp的质量分数超过6%时,在摩擦过程中材料和对偶发生严重磨损;α-SiCp含量对铜基粉末冶金摩擦材料的摩擦磨损性能影响不显著;当SiC颗粒的质量分数为2%~6%时,β-SiCp相比α-SiCp更适合作为摩擦组元用于铜基粉末冶金摩擦材料中。     

超高效液相色谱-串联质谱法测定北京市区灰霾天气空气颗粒物中的全氟化合物

全氟化合物（PFCs）是全球性持久性有毒有机污染物（POPs）中危害最为严重的一类物质,而有关环境气溶胶中所含PFCs的报道却较少,尤其是北京市区灰霾天气PM2.5和PM10中PFCs含量研究未见报道。本文应用甲醇和丙酮混合溶剂提取采集的大气颗粒物样品,超高效液相色谱-串联质谱法（UPLC—MS／MS）测定颗粒物中全氟丁烷磺酸、全氟己烷磺酸、全氟辛烷磺酸、全氟辛烷酸、以及全氟十一烷酸、全氟十二烷酸、全氟十三烷酸和全氟十四烷酸等八种全氟化合物的含量。采集了2014年3月底到4月上旬北京市区北四环附近苏州街南典型的灰霾天气空气颗粒物样品。结果表明PM2.5和PM10浓度分别为73．8-260μg／m^3和219-398μg／m^3,所采集的样品中均检出PFCs,PM2.5中PFCS的总含量在13．5-115pg／m^3,平均值78．2pg／m^3,在PMl0中含量在22．2-160pg／m^3,平均值105pg／m^3,颗粒物中成分以全氟辛烷酸、全氟己烷磺酸和全氟辛烷磺酸为主。