中国“入世”与科技创新发展

世纪相交之际,上海举办了"科技论坛"学术研讨活动,集中展示了科学家、专家、政府官员和企业家对新世纪发展和"十五"规划的科学技术智慧与真知灼见,提出了建设新上海的大量精彩金点子,业已引起市府领导的重视。 　　为此,本刊按有关专题择要发表。本期刊登"中国入世与科技创新发展"主题研讨会有关内容。     

LF(VD)精炼工艺对控制28MnCr5齿轮钢中硫和硫化物的影响

试验了45 t LF精炼渣的碱度、喂硫线和脱氧工艺对28MnCr5钢(％:0.25～0.30C、0.60～0.80Mn、0.020～0.035S、0.80～1.00Cr)硫含量的控制、氧化物含量和钢中硫化物的影响。结果表明,LF精炼渣碱度控制在2.8～5.1喂硫线,VD后硫的回收率达80％～90％;钢中氧化物级别≤1.5级;精炼结束喂适量CaSi线可改善钢中硫化物的形貌。     

冷却速度对含Ti非调质钢中晶内铁素体形成的影响

观察了不同冷速下获得的含Ti非调质钢的显微组织,并绘制了静态连续冷却转变曲线(CCT曲线).结果表明,在0.5～2.5℃/s的冷速范围内,会有晶内铁素体析出,其中在2℃/s冷却时可以获得大量针状铁素体.空冷条件下获得细小无序分布的晶内铁素体,明显提高试验用含Ti非调质钢的韧性.     

HN2154非调质钢过冷奥氏体连续冷却转变曲线研究

采用热膨胀仪、金相显微镜与维氏硬度计对轿车前悬挂前后控制臂HN2154高氮非调质钢的过冷奥氏体在不同冷速条件下的连续冷却转变曲线(CCT)进行了测定,观察和测试了该试验钢在不同冷却条件下的组织号性能.结果表明,所测定的CCT曲线的可靠性已经得到实际工业生产的验证.     

改质沥青对冶金炼焦过程单种煤成焦性质的影响

 针对宣化钢铁公司焦化厂所用的种煤,分别研究改质沥青的加入量,对灰分Ad、挥发分Vdaf、硫分St,d、收缩指数X和煤粘结指数G等主要成焦性能的影响。研究表明：加入改质沥青小于5％时,对瘦煤、1/3焦煤、焦2煤和弱粘煤的灰分、硫含量的影响不大,对弱粘煤、1/3焦煤和瘦煤的粘结指数没有明显的影响,对弱粘煤和瘦煤的胶质层厚度影响也不明显;随着改质沥青的加入,焦2煤和1/3焦煤的胶质层厚度显著增加,焦2煤的粘结性指数也显著增加。加入改质沥青大于5％时,随着改质沥青的加入,瘦煤和弱粘煤的灰分下降明显,焦2煤硫含量降低增大,瘦煤的胶质层厚度显著增加,弱粘煤、1/3焦煤和瘦煤的粘结指数有明显增加。加入改质沥青对各单种煤收缩指数影响规律较复杂,弱粘煤和1/3焦煤的收缩指数在配入3%改质沥青降到最小,以后又都明显增大,但改质沥青达到5%~6%后又减小;焦2煤和瘦煤在加入量小于5％时,收缩指数变化不大,加入量大于5％时才明显减少。     

Reaction between Lanthanum and Phosphorus in Steel

P always causes low temperature emhrittlement and temper embrittlement owing to itsgrain boundary segregation[']. Garcia C I etal. [2) reported a complex compound containingLa, O I S and P, in which LaZOZS acted as anucleation site and Fe-P precipitated on thesurface of the oxysulfide. Nevertheless, thermodynamic calculation by Seah M P showedthat La could not react with P in steel unlesstemperature is lower than 1100 T, sinceGibbs free energy of formation of LaP is positive above thi…     

Excel在企业工时定额工作中的应用

将Excel引入企业工时定额管理进行数据分析.     

Y/Eu co-doped TiO2:synthesis and photocatalytic activities under UV-light

Y and Eu co-doped nano-TiO2 photocatalysts were successfully prepared via a sol-gel method and characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), ultraviolet-visible spectrophotometry(UV-vis), photoluminescence(PL) and Fourier transform infrared(FT-IR) spectra. Experimental results indicated that Y and Eu doping inhibited the growth of crystalline size and the transformation from anatase to rutile phase and had the function of reducing particle reunion. At the same time, co-doping could also enhance the absorption in visible region and then narrowed the band gap. The photocatalytic activities of the samples were evaluated by the degradation of methylene blue(MB) under ultraviolet(UV) light irradiation, which showed much enhanced photocatalytic activities over un-doped TiO2. The degradation rate of 1.5% Y/Eu-TiO2 of methylene blue was 86%, which was about 5 times of that of un-doped TiO2, and the possible reasons for the improvement of photocatalytic activities were analyzed. In this experiment, the dopant amount of rare earth was 1.5% and the ratio of Y:Eu was 2:3 for the maximum photocatalytic degradation, and the sample calcined at 500 oC showed the best reactivity. For the best samples above, the removal rate of phenol under visble light was 53% whthin 2 h.     

SiO2-Al2O3-CaO-MgO系夹杂物低熔点区域优化及控制的热力学计算

为了预测CaO-Al2O3-SiO2-MgO系夹杂物具有良好变形能力的成分控制范围,首次通过热力学软件Fact-Sage对CaO-Al2O3-SiO2-MgO系液相投影图、低熔点区域大小进行了计算分析,并以阀门弹簧钢60Si2CrA为例,对CaO-Al2O3-SiO2-MgO系低熔点夹杂物的生成条件进行了探讨.结果表明...     

基于单片机的红外测温仪设计

设计以单片机作为整个测温仪的核心,结合A/D转换器、液晶显示器等外部设备,在软件设计和硬件设计的基础上,设计出一种拥有汉字显示逻辑判断等智能型电子测温计。它提供了一种新的温度测量方案,采用红外温度传感器来测量温度信号,可同时测量目标温度和环境温度,并将测量的数据经过放大器,转换器送给单片机处理,之后送数码管显示。红外测温打破了传统的测温模式,它响应快、测量精度高、可靠性高、范围广,为非接触测量,因而不易损坏。该温度计以准确快捷的测量功能、清晰易懂的数字化显示方便人们日常生活使用。