静电纺丝中基布的静电性能对纺丝的影响研究

静电纺纳米纤维存在分子链取向较低、强度低等缺点,这些缺点使纳米纤维毡不能单独使用,必须沉积在基布上。使用了1#铝箔、2#聚丙烯熔喷驻极非织造布、3#聚丙烯熔喷非驻极非织造布、4#聚丙烯纺粘非织造布4种不同的基布进行静电纺丝。对基布的静电性能进行测试,结果为标准情况下静电压排序为:2#>4#>3#>1#;标准情况下静电压衰减率排序为:1#>3#>4#>2#。研究同时发现纺丝过程顺畅程度由好到差及收集纤维毡产生的"小白点"由少到多的顺序均为1#>2#>3#>4#。静电纺丝采用不同的基布影响纺得的纤维均匀分布但不影响纤维的直径。     

Evolution mechanism of active groups and thermal effects of Chinese lignite in low-temperature oxidation

Abstract

The evolution of active groups at low temperature was examined using Chinese lignite by infrared technology and X-ray photoelectron spectroscopy (XPS). The results showed that the hydroxyl, aliphatic ether, methylene, and methyl groups played important roles in the low-temperature oxidation of lignite below 200?°C. Carbonyl and carboxyl groups were important intermediates. Thus, a multi-step evolution mechanism involving the hydroxyl, aliphatic ether groups, and alkane was reasoned to describe the low-temperature oxidation of lignite. In addition, according to the oxidation kinetics experiment and the evolution laws of the active groups, the ratios of the reaction lines were determined considering the accuracy of thermal effects. The thermal effects and the heat release intensities of each temperature interval were obtained based on the evolution mechanism and the reaction ratios. The shortest spontaneous combustion period of lignite was calculated and compared with the experimental value, which proved that the reasoned evolution mechanism of the active groups and the calculations of the thermal effects were reliable.     

有机硅改性丙烯酸酯/纳米SiO2复合低表面能防污涂料

用逐步滴加引发剂合成有机硅改性丙烯酸树脂,将纳米SiO2、铁红、滑石粉分散于有机硅改性丙烯酸树脂中,制成低表面能防污涂料.结果表明,当纳米SiO2的加入量为5.5%～8%时,涂膜与液体的接触角大于98°,涂膜具有较低的吸水率,具有一定的防污效果.     

原料结构对高MgO烧结矿生产的影响

原料结构的优劣对烧结生产技术质量指标具有决定性的影响,尤其是在低硅烧结条件下生产高MgO烧结矿.本文介绍了以白云石、高镁粉作MgO熔剂添加剂生产高MgO烧结矿时,原料结构对烧结生产影响的试验研究情况.研究结果表明,只要原料结构选择适宜,无论使用何种MgO熔剂添加剂,均可在低硅条件下生产出具有高强度的高MgO烧结矿.     

安钢2200m3高炉清洁生产实践

介绍了安钢2200m^3高炉采用了TRT余压发电、汽轮鼓风机、INBA渣处理、低压脉冲除尘等多项先进的清洁生产工艺,节约资源、综合利用、减少污染排放的生产实践。     

First-principles study on the mechanical,thermal properties and hydrogen behavior of ternary V-Ni-M alloys

Studying hydrogen behavior in alloys and the mechanical properties of alloys are essential to various practical uses,such as separation membranes,as well as hydrogen embrittlement protection.In order to further develop the non-Pd-alloy membranes used in hydrogen separation,the mechanical,thermal properties of V14NiM(M= Al,Fe,Si,Ti,Zn)and hydrogen solubility and diffusion behaviors of V-based ternary alloys were studied by first principles calculation.The results indicated that the hydrogen solution energies of V-Ni-M are greater than pure vanadium.And the mono-vacancy in pure vanadium can capture 6 H atoms while the V-Ni-M alloys can only capture 5 H atoms.Therefore,the V-Ni-M alloys exhibit lower solubility of hydrogen and higher brittleness resistance to embrittlement compared with pure vanadium.And the diffusion coefficients of V-Ni-M alloys are smaller than that of pure vanadium thanks to smaller hydrogen solubility.The hydrogen solubility and hydrogen permeability can maintain relatively balanced.The study of mechanical properties suggests that the V-Ni-Ti has the best resistance to deformation and pure vanadium has the best ductility.Moreover,V-Ni-Si alloy has the smallest thermal expansion coefficient in the temperature range of 473-723 K,which is the temperature of hydrogen separation,indicating that V-Ni-Si is the best for hydrogen separation according to thermal properties.     

基于冗余关系分析的传感器自诊断设计方法研究

工业过程中传感器数量众多且可靠性要求高,而传统定期检测评估其健康状况的方式不但费时费力且不能满足传感器 智能化的发展需求。 针对这一问题,提出了一种基于测量数据统计相关性的传感器自诊断设计方法。 利用传感器测量数据建 立其统计关系模型,借助自编码器提取传感器数据特征并将其编码为二进制形式。 在同时考虑传感器测量数据统计独立和统 计相关两种情况下,在有参考值时,通过引入故障检测概率和误检概率建立了独立统计模型实现传感器的故障自诊断;在无参 考值情况下,借助高斯 Copula 函数建立多元统计依赖模型评估参数之间的相关性,并利用贝叶斯理论在不依赖参考值的情况 下自学习获取传感器的健康状况。 本研究以镍闪速炉系统为例,两种模式下测量系统中健康传感器的故障检测后验概率达到 了 0. 92,即故障统计模型的参数与建模期望相符。 实验结果表明,所提方法在两种模式下均能准确识别出测量系统中的故障 传感器,验证了所提方法的有效性与可行性。     

Developement of neutral polymeric bonding agents for propellants with polar composites filled with organic nitramine crystals

Versatile neutral polymeric bonding agents (NBPA's) have been developed for energetic propellants in which polar HMX particles are dispersed in a polar binder matrix containing highly polar plasticizers (TMETN, NG, etc.). Using a semi-empirical approach through adjustment of solubility parameters and molecular weight, neutral acrylonitrile interpolymers were synthesized which mix uniformly with the submix and still have a high affinity for the HMX particles when they are added. Addition of about 0.2 % w/w of NPBA to HMX-filled PEG binders increases the strength by a factor of as high as five compared to samples with no NPBA, and also eliminates the sudden decrease in modulus (knee) which occurs at relatively low elongation. The degree of filler reinforcement achieved by our NPBA's in energetic propellants is far superior to that achieved by adding nitrocellulose or any other previously proposed bonding agents, and similar to the effect of precoating the HMX particles with polyurea shells.     

Extraction of cerium(III) with N,N′-dimethyl-N,N′-dioctyl-diglycolamide in [Bmim][PF6] compared in 40% octanol/kerosene

The extraction of Ce(III) nitrate has been investigated by using N, N′-dimethyl-N, N′-dioctyl-diglycolamide (DMDODGA = L) as extractant with 1-Butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF₆]) as diluent in comparison with 40% octanol/kerosene. DMDODGA in two different diluents shows good extraction ability for Ce(III), but the trends are quite different depending on the concentrations of the ligand in solvent phase and nitric acid in aqueous phase. The slope analysis method is used to obtain the stoichiometric ratio of the extracted complexes. 1:3 complex of Ce(III) to DMDODGA may be formed in both systems, while 1:2 complex may be also formed in DMDODGA-40% octanol/kerosene system. The extraction of Ce(III) is by the cation exchange mechanism in DMDODGA-[Bmim][PF₆] system. Unlike the expected positively charged 1:3 complex of Ce(III) formed in the DMDODGA-40% octanol/kerosene system, the 1:2 complex is assumed to be a neutral complex with two DMDODGA molecules bonding to Ce(III). In addition, the stronger interaction between the C = O groups of L and Ce(III) in the DMDODGA-[Bmim][PF₆] system than in the DMDODGA-40% octanol/kerosene system is confirmed by IR spectroscopy.     

某企业不同工种的放射工作人员发生甲状腺结节风险分析

采用职业健康体检资料和问卷形式,利用单因素和多因素logistic回归模型,分析探讨某企业内不同工种的放射工作人员暴露在低剂量电离辐射环境下发生甲状腺结节的风险。结果表明,放射工作人员中以混合射线组甲状腺结节发生风险最高,随着年龄和放射工龄的增加发生风险会增加;性别不同与甲状腺结节发生风险有关。