IMPACT OF APPLYING BCTMP TO WOOD-FREE LWC ON ITS PERFORMANCE

INTRODUCTIONBleached CTMP (BCTMP) is popular in many commercial paper grades, such as packaging, tissue, uncoated wood-free fine papers. There is a strong economic incentive to substitute BCTMP for kraft pulp in producing wood-free light weight coated paper (LWC). Wood free LWC is used mostly for high-speed heatset web offset (HWSO) color printing. With a low basis weight and also low coat weight, the strength, surface and structural properties of the LWC wood-free paper are al…     

板底粘钢加固区域的确定

借助有关文献、工程应用软件和特此编制的薄板弯曲有限元程序提出了两种确定板底粘钢加固区域的方法。     

冶金级硅酸洗提纯研究

冶金工艺被认为是非常有前途的一种有别于传统的西门子工艺而且能够满足市场对太阳能级硅需求的工艺.冶金级硅的预处理是冶金提纯工艺路径中非常重要的一个环节,因为酸洗可以有效地去除硅中的金属杂质例如铝、铁和钙等.通过系统性的对比试验对酸洗工艺去除硅中杂质的效果进行了详细的研究,分别探讨了酸的种类、酸的浓度、酸洗时间、酸洗温度以及硅粉颗粒粒径对杂质去除效率的影响.研究结果表明最佳的酸洗工艺参数为15%的盐酸,80℃,10h和100μm.在最佳酸洗工艺参数条件下金属杂质铝、铁和钙的去除率分别为70.90%、94.82%和82.69%.     

Investigation of the interfacial water structure on poly[2-（dimethylamino）ethyl methacrylate] at the air/water interface by sum frequency generation vibrational spectroscopy

The effect of pH on the conformation of surface alkyl groups and the structure of interfacial water molecules on poly[2-(dime-thylamino)ethyl methacrylate](PDEM) at the air/water interface were investigated with sum frequency generation vibrational spectroscopy(SFG-VS).At pH 4.1,the hydrogen bonding SFG spectra were similar to that of the air/pure water interface.As the pH increased from 5.4 to 9.6,the SFG intensities of both highly ordered hydrogen bonding(3200 cm-1 band) and less-ordered hydrogen bonding(3400 cm-1 band) were enhanced because of the charge-induced effect of deprotonated PDEM.The free OH peak disappeared completely because it was replaced by interfacial PDEM molecules.At pH 11.5,a new spectral band appeared at about 3580 cm-1 in the ppp and sps spectra,and this could be assigned to the C2v asymmetric stretching mode of the water molecules through molecular symmetry simulation.These hydrogen bonding structures are fully consistent with the conformational change of PDEM alkyl groups,and PDEM molecules act as a Hofmeister solvent.PDEM molecules are kosmotropic when they are charged and become more chaotropic as the pH increases.     

埋氧层及铝层对SOI／玻璃静电键合的影响

介绍了SOI／Pyrex玻璃静电键合的实验过程和实验现象,利用电流表对静电键合电流进行测量。发现埋氧层厚度越厚,键合电流越小,键合波扩散速度越小。提高键合电压,能有效增大键合电流及加快键合速度。实验也表明玻璃表面溅射铝层对键合产生较大影响。理论分析了产生这些现象的原因,得出埋氧层厚度和键合电压与静电力的关系式。还提出从阳极引一探针电极到SOI器件层,提高玻璃耗尽层与器件层之间电压,实现厚埋氧层SOI片与玻璃键合的方法。     

含锌电炉粉尘配碳球团的冶金特性

以某钢铁公司含锌电炉粉尘为原料,配入适当的无烟煤制成含碳球团,焙烧球团通过还原煤保护冷却至室温后进行化学分析·研究了1150℃～1300℃的范围内,温度、时间和内配煤量对锌、铁的还原速率以及球团抗压强度的影响·研究结果表明:锌、铁的还原率均随焙烧温度、焙烧时间以及内配煤量的增加而提高;抗压强度随焙烧温度、焙烧时间的增加而增高,但随内配煤量的增加出现极值点·焙烧球团最佳的工艺参数:焙烧时间为15min,内配煤量为13 04%,焙烧温度为1250℃·此时锌的还原率为98 43%,金属化率为94 51%,抗压强度为800 6N/球·     

Effects of SiO2 on the preparation and metallurgical properties of acid oxidized pellets

The effects of SiO₂ content on the preparation process and metallurgical properties of acid oxidized pellets, including compressive strength, reduction, and softening–melting behaviors, were systematically investigated.Mineralogical structures, elemental distribution, and pore size distribution were varied to analyze the mechanism of the effects.The results show that with an increase in SiO₂ content from 3.51 wt%to 7.18 wt%, compressive strength decreases from 3150 N/pellet to 2100 N/pellet and reducibility decreases from 76.5% to 71.4%.The microstructure showed that pellets with high SiO₂ content contained more magnetite in the mineralogical structures.Additionally, some liquid phases appeared, which hindered the continuous crystallization of hematite.Also, the softening–melting properties of the pellets clearly deteriorated as the SiO₂ content increased.With increasing SiO₂ content, the temperature range of the softening–melting zone decreased, and the maximum differential pressure and the comprehensive permeability index increased significantly.When acid oxidized pellets are used as the raw materials for blast furnace smelting, it should be combined with high basicity sinters to improve the softening–melting behaviors of the comprehensive charge.     

Processing and characterization of the microstructure and mechanical properties of Al6061–TiB2 composite

In the present research, aluminum metal matrix composites were processed by the stir casting technique. The effects of TiB2 rein-forcement particles, severe plastic deformation through accumulative roll bonding (ARB), and aging treatment on the microstructural charac-teristics and mechanical properties were also evaluated. Uniaxial tensile tests and microhardness measurements were conducted, and the micro-structural characteristics were investigated. Notably, the important problems associated with cast samples, including nonuniformity of the rein-forcement particles and high porosity content, were solved through the ARB process. At the initial stage, particle-free zones, as well as particle clusters, were observed on the microstructure of the composite. However, after the ARB process, fracturing phenomena occurred in brittle ceramic particles, followed by breaking down of the fragments into fine particles as the number of rolling cycles increased. Subsequently, com-posites with a uniform distribution of particles were produced. Moreover, the tensile strength and microhardness of the ARB-processed com-posites increased with the increase in the reinforcement mass fraction. However, their ductility exhibited a different trend. With post-deforma-tion aging treatment (T6), the mechanical properties of composites were improved because of the formation of fine Mg2Si precipitates.     

黏结指数G值表征炼焦煤结焦性的局限性研究

对7组相同变质程度和黏结指数G值炼焦煤煤岩显微组分、高温塑性和成焦光学组织结构进行研究。结果表明,相同变质程度和G值的炼焦煤高温塑性差异明显,软化温度相差3~29℃,固-软温度区间相差8~42℃,最大基氏流动度比值为1.3~1266;其炼焦煤焦炭光学组织结构差异亦明显,粗粒镶嵌结构占比相差9%~43%,同性结构占比相差2%~16%,纤维结构占比相差15%~36%。因此,G值对煤料受热所产生胶质体的数量能较好地表征,但对其结焦性的判断存在缺陷。     

基于ANSYS的扁平箱梁桥粘贴钢板加固方案优化研究

结合青岛市某主干道立交桥扁平箱梁桥加固工程,用有限元分析软件ANSYS对扁平箱梁的主梁粘贴钢板加固技术进行了数值模拟分析。通过比较不同加固方案加固前后的应力、位移等分布变化规律,评价各方案的加固效果,并最终得出最优加固方案。结果表明:三种粘贴钢板加固方案都能够显著增强桥梁的承载能力,其中C型方案加固效果最好。并将模拟结果与理论计算值进行了比较,分析了误差原因。