Amorphization reaction of Ni-Ta powders during mechanical alloying

This study examined the amorphization behavior of Ni _x Ta_100−x alloy powders synthesized by mechanically alloying (MA) mixtures of pure crystalline Ni and Ta powders with a SPEX high energy ball mill. According to the results, after 20 hours of milling, the mechanically alloyed powders were amorphous for the composition range between Ni₁₀Ta₉₀ and Ni₈₀Ta₂₀. A supersaturated nickel solid solution formed for Ni₉₀Ta₁₀, as well. X-ray diffraction analysis reveals two different types of amorphization reactions. Through an intermediate solid solution and by direct formation of amorphous phase. The thermal stability of the amorphous powders was also investigated by differential thermal analysis. As the results demonstrated, the crystallization temperature of amorphous Ni-Ta powders increased with increasing Ta content. In addition, the activation energy of amorphous Ni-Ta powders reached a maximum near the eutectic composition.     

Improved coupled-microstrip filter design using effective even-mode and odd-mode characteristic impedances

The transmission zeros of two coupled-microstrip circuits are studied in this research. Estimates for the frequencies of transmission zeros are given. A new concept of effective even- and odd-mode characteristic impedances is introduced. Useful design equations are given for improving the passband responses that are inherently distorted by different mode velocities. Finally, two filters with different topologies are designed for their zeros to be at the frequencies of the spurious harmonics and, thus, yield wide out-of-band rejections.     

碎屑岩酸化中含铝垢形成机理与预防

3种含5％盐酸的土酸（HCI／0．5％HF，HCI／1．0％HF，HCI／8％HBF4）与6种碎屑岩储层矿物（钾长石，斜长石，蒙脱石，高岭石，伊利石，绿泥石）在60℃静态反应0．5～12小时，测定残酸中可溶Si、Al浓度、残酸蒸发残渣元素组成厦矿物组成、结构。列表给出了残酸中可溶Si、Al浓度范围厦平均值（单位mg／L）并作了分析讨论：残酸中Si、Al浓度很高，在某些情况下Al浓度甚至高于sj啦度；酸．矿物反应初期（0．5～2．0小时）Si、Ai浓度起伏变化，这是各种垢的主要形成期：长石类、高岭石厦蒙脱石与酸反应后的残酸（厦残酸蒸发残渣）的Si／Al比小于原始值，说明长石晶体[AlO4]^5-四面体和黏土晶体[Al4（OH）6]^6＋八面体的酸蚀速率和程度大于相应的[SiO4]^4-四面体；酸蚀后各矿物X衍射峰无明显变化．即矿物结构无大政变，无新矿物生成。根据文献资料讨论了水溶液中各种含铝离子的平衡反应，给出了分布系数与pH的关系，讨论了碎屑岩酸化中含铝垢的形成反应和条件：在酸性介质中形成Na3AIF6、K2AlF5、AlF3等垢．在弱酸性介质中形成Al（OH）3垢，在高温下（91℃）pH=2．5时形成AlF（OH）2垢。讨论了防止碎屑岩酸化中生成含铝垢的措施。图1表1参1l。     

聚合物驱采出液中HPAM的分子参数、结构及形貌研究

富集并提纯了锦州9-3(JZ9-3)油田W7-4井聚驱采出液中的部分水解聚丙烯酰胺(HPAM),利用红外光谱分析了HPAM纯化品的结构,利用扫描电镜、原子力显微镜和动态光散射分析了其微观结构形貌,并测定了浓度和相对分子质量.结果表明,采出液中的HPAM聚集体是以某一中心向四周放射的多层立体网络状结构,其大分子具有树枝状的支化结构;采出液中HPAM与驱油用HPAM具有相同的结构与特征基团;与原驱油用聚合物相比,采出液中HPAM水化分子粒径由约720 nm减至约280 nm,仅含有少量Rh>1μm的水化分子;浓度由1270 mg/L减至400 mg/L;经过地层的剪切、降解等作用,HPAM的相对分子质量大幅度减小,由12×106g/mol减至1.52×106g/mol.     

创鲁班精品工程 树企业社会形象

通过对创"鲁班奖"工程的策划、实施,精心准备"鲁班奖"的复查,获得高度评价,提升企业形象。     

Studies on the synthesis and electrocatalytic properties of hollow PdAu nanocatalysts

Pd-based nanocatalysts (NCs) are the potential substitutes for the Pt-based NCs used in the direct methanol fuel cells (DMFCs) because of their lower cost and comparable catalytic performance. The catalytic performance of Pd-based NCs is highly connected with the morphology, composition and surface structure of the catalysts. Here, solid bimetallic PdAu and hollow PdAu NCs were synthesized by a successive reduction and co-reduction method, respectively, using P123 both as reducing reagent and protectant. Compared with the solid PdAu NCs and commercial Pd black catalyst, the hollow PdAu NCs exhibited enlarged electrochemical surface areas (ECSA), and showed an enhanced electrocatalytic activity and stability for methanol oxidation reaction (MOR) in alkaline solution. The excellent electrocatalytic performance is contributed to the unique hollow structure and alloy effects of the PdAu NCs.     

Electrochemical performance of Al_2O_3 pre-coated spinel LiMn_2O_4

Al_2O_3-coated spinel LiMn_2O_4 cathode materials, presintered LiMn_2O_4(P-LMO), and calcined LiMn_2O_4(C-LMO) were synthesized by chemical deposition and thermal treating method using presintered and calcined LiMn_2O_4 as precursors. The crystal structure, morphology,the thickness of the coating layer, and particle size of prepared samples were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), high-resolution transmission electron microscopy(HRTEM), and Malvern instruments. The average particle size of P-LMO with like-spheres(0.3 μm) is much smaller than that of C-LMO(0.5 μm). The Al_2O_3 layer of P-LMO can effectively reduce the charge transfer resistance and inhibit the Mn dissolution. The electrochemical performance of P-LMO is better than that of C-LMO. It is found that the LiMn_2O_4 cathode materials have excellent electrochemical cyclability by coated 2 mol% Al_2O_3 at the surface of presintered material. The initial discharge capacity of the material with 2 mol% Al_2O_3-coated is 114.0 m Ah·g~(-1) at 0.1 C rate and 55 ℃, and the capacity retention is 87.3 % at 0.5 C rate.     

非均质油藏封窜及化学驱复合技术研究

利用单层均质模型及并联填砂管模型,评价改性淀粉凝胶体系的调剖性能。该凝胶体系由4%改性淀粉、4%丙烯酰胺单体、成胶控制剂按一定比例组成。凝胶体系成胶前的选择注入性良好,成胶后的残余阻力系数为834～2548,突破压力梯度高于50MPa/m,封堵率大于99%,可有效解决水窜流问题。利用双层非均质岩心模型,考察3种后续驱替段塞对提高采收率的影响。由0.3%聚丙烯酰胺、0.3%烷基苯磺酸钠和0.1 g/L NaOH组成的三元驱、0.3%聚丙烯酰胺及水驱的采收率增幅分别为20%、17%和10%。"改性淀粉凝胶体系+三元复合驱"组合调驱中,改性淀粉凝胶可进一步开采高渗层位残余油,三元复合驱在封堵后可有效启动低渗层位,整体提高采收率37%。     

Si3N4颗粒及SiC晶须强韧化MoSi2复合材料的低温氧化行为

对Si₃N₄颗粒及SiC晶须强韧化MoSi₂复合材料在773K下的氧化行为进行了研究.通过热重量分析法（TG）分析了MoSi2及其复合材料MoSi₂-Si₃N_4(p)和MoSi₂-Si₃N_4(P)SiC_(w)在773K下的氧化性能, 采用SEM和X射线衍射测定其表面形貌和氧化物相组成.结果发现：在773K下, 纯MoSi₂和MoSi₂+20vol%Si₃N₄均发生了“Pesting”氧化, 氧化过程服从直线规律, 氧化产物层疏松, 氧化产物主要为MoO₃; MoSi₂+40vol%Si₃N₄氧化服从抛物线规律, 速率常数K_p为0.04mg²/(cm⁴·h), 氧化层致密, 成分主要为SiO₂、Si₂N₂O, 增加Si₃N₄的含量可显著提高MoSi₂的抗“Pesting”氧化能力; MoSi₂+20vol%Si₃N₄+20vol%SiC发生了严重的粉化现象, 氧化产物主要为短针状MoO₃.     

Flash fixation of heavy metals from two industrial wastes into ferrite by microwave hydrothermal co-treatment

Flash fixation of heavy metals from electroplating wastewater (EPW) and pickling waste liquor (PWL) into ferrite lattice can be investigated by microwave hydrothermal process. The toxicity of wastewater may be reduced by the redox reaction between Cr(VI) in electroplating wastewater and Fe(II) in pickling waste liquor. Box-Behnken design (BBD) experiment gives optimal process condition of ferrite formation as follows: wastewater volume ratio (V_PWL:V_EPW = 0.20), pH value 11 and retention time 15 min, on which formed ferrite has a soft magnetic property with high saturation magnetization (M_s) 47.4 emu/g. The rapid ferrite process has lower activation energy 7.01 kJ/mol according to grain growth kinetics. Concerning the environmental and economy, we introduced a new and interesting method for water remediation simultaneously synthesizing ferrite by using microwave mediated hydrothermal processes.