NaY分子筛担载FeSO4催化剂用于氨气还原NOx的性能

研究了分子筛担载FeSO₄催化剂在SCR脱硝反应中的催化性能和反应机理。实验结果表明,在同等工况下分子筛担载FeSO₄后的催化剂具有更好的物理结构,与纯FeSO₄相比脱硝率可提高将近20%。经Mossbauer谱分析,催化剂制备过程中Fe²⁺转化为Fe³⁺,其具体存在形式为Fe (OH)SO₄与Fe₂O(SO₄)₂,前者催化脱硝效果优于后者。原位红外分析结果表明,吸附在分子筛担载催化剂表面的氨与气相中的NO反应,Fe离子是吸附及发生催化氧化还原反应的活性中心。与钒、钛系相似文献   

四丁基氯化铵水合物的蓄冷特性

探讨了一种新型季铵盐——四丁基氯化铵的水合物作为蓄冷工质的可行性,对其蓄冷特性进行了实验研究:研究了溶液浓度、循环次数及添加成核剂硼砂对四丁基氯化铵水合物的生长特性的影响。实验结果表明:浓度为40%的TBAC溶液相变过程相对稳定,更适合空调蓄冷工况;添加成核剂硼砂使TBAC溶液的相变温度降低了2℃,结晶过冷度减小2℃;经过多次重复水合反应后,溶液在结晶过程中的过冷度减小了1.5℃,相变温度无变化。利用DSC测试得到四丁基氯化铵水合物相变温度为10.41℃,相变潜热为197.707J.g-1。     

SMES超导磁体动态载荷温度场仿真分析

研究了超导磁储能磁体在动态载荷作用下的热稳定性,基于有限元方法构建了直接冷却高温超导磁储能磁体的数学模型,进行了充放电过程磁体温度场仿真,研究表明,在间断载荷作用下磁体具有较好的热稳定性,在连续载荷作用下,控制励磁电流速度和间隔时间可保证磁体的运行温度在30 K以下。     

无机/有机复合载体SiO_2/MgCl_2·xBu(OH)_2/PSA负载TiCl_4催化剂的制备及其乙烯聚合行为

采用SiO2、MgCl2以及苯乙烯-丙烯酸共聚物(PSA)合成了SiO2/MgCl2.xBu(OH)2/PSA无机/有机复合载体并负载TiCl4,得到具有SiO2无机支撑层、MgCl2.xBu(OH)2加合物以及PSA有机载体3种化学环境的SiO2/MgCl2.xBu(OH)2/PSA/TiCl4复合载体负载催化剂。研究了复合载体组成对催化剂的载钛量、形貌以及乙烯聚合行为的影响。当PSA存在时,催化剂的载钛量明显降低。乙烯/1-己烯共聚的反应动力学结果表明,与SiO2/MgCl2.xBu(OH)2/TiCl4相比,无机/有机复合载体负载催化剂的动力学曲线具有一段较长的受扩散控制的诱导期,并且随着PSA质量分数的增加,诱导期延长,动力学曲线由衰减型转变为上升-稳定型。由于复合载体具有多种化学环境,使得负载催化剂活性中心种类增多,共聚性能提高,聚乙烯产品分子量分布变宽,熔流比显著提高。根据聚乙烯树脂的扫描电镜照片,探讨了复合载体负载催化剂在聚乙烯生长过程中的破碎机理。     

Improvement of porcine interferon-α production and ATP regeneration efficiency by reducing induction temperature

在10 L发酵罐、控制甲醇浓度的条件下,考察了诱导温度对毕赤酵母发酵生产猪α-干扰素（pIFN-α）性能的影响。结果表明,温度对pIFN-α表达的影响明显,20℃低温有利于pIFN-α的表达,该条件下pIFN-α最高活性可达1.5×106 IU·ml^-1,是30℃传统诱导生产时最高活性（1.0相似文献   

利用液化天然气冷能捕集CO_2的动力系统的集成

为提高液化天然气(LNG)冷能的利用效率和CO2近零排放动力循环的发电效率、降低CO2减排的能耗,在对CO2近零排放动力循环利用LNG冷能进行火用分析的基础上,提出了一个以天然气为介质的Rankine循环与CO2近零排放动力循环进行集成的动力系统模型,可以在保持CO2预冷和液化所需冷能不变的情况下,将深冷部分的LNG冷火用转换为电能。研究结果表明,集成后动力系统中LNG冷火用的利用效率从34.9%提高到55.7%,整个动力循环的火用效率可达到57.9%。同时,对影响以天然气为介质的Rankine循环发电效率的参数进行了分析。     

基于粒子群优化Hopfield网络匹配的稀相颗粒速度测量

提出了一种基于粒子群算法(PSO)和Hopfield神经网络相结合的粒子跟踪测速算法。该方法采用高速摄影系统拍摄气固两相流的稀相颗粒运动图像,经图像处理后,提取形心参数。将粒子匹配问题转化为优化问题,采用粒子群优化算法与Hopfield神经网络相结合的方法进行优化,求出最优解来实现颗粒的正确匹配,然后计算出颗粒的速度矢量,并与互相关法求出的速度进行对比,实验结果表明,该方法能准确地跟踪稀相颗粒,是一种有效的稀相流场速度测量方法。     

化学修饰啤酒酵母菌对铀的吸附特性

以甲醛为交联剂, 将胱氨酸修饰到啤酒酵母菌(SC)上, 并采用海藻酸钠和明胶固定化, 得到一种新型的生物吸附剂--修饰啤酒酵母菌(MSC)。通过红外光谱(IR)分别表征了两种吸附剂的结构, 考察了其吸附铀的主要影响因素即溶液pH值、吸附时间等。结果表明: MSC细胞表面具有大量吸附铀的基团, MSC和SC吸附铀的最佳条件是: pH值为6.0, 相似文献   

高效能两段组合式煤气化过程热态试验

针对现有气流床气化技术在显热回收方面的不足,华东理工大学洁净煤技术研究所创新性开发煤基两段组合式气化工艺。在所建立的两段组合式煤气化炉热态试验装置上,考察了二段处理煤量和一段出口煤气组成对出口煤气热值、有效气浓度、二段碳转化率、水蒸气和二氧化碳转化率的影响。试验结果表明此气化工艺能有效利用一段炉煤气中的显热,提高气化炉出口煤气热值;二段适宜加入褐煤量为1400g,是一段处理量的10%;二段加煤量过多会降低二段煤层反应温度和促使焦油的生成;随着一段气化炉出口煤气所含水蒸气、CO2等气化剂浓度的增加,其对显热回收的作用就更明显;该工艺能减少CO2排放,具有良好的环境效益。     

水煤浆气流雾化的初次破裂特性

以水煤浆和空气作为实验介质,利用高速摄像仪对同轴双通道喷嘴水煤浆气流雾化的初次破裂过程进行了实验研究,重点考察了在喷嘴出口附近水煤浆的射流核心长度和振荡频率等特征。研究结果显示,实验中水煤浆的破裂模式为非轴对称雷利破裂模式,根据实验结果,得到了浆体的量纲1射流核心长度与气速和液速之间的关系式。雾化过程中浆滴的产生与水煤浆射流振荡有关,研究了其Strouhal数与Weber数和液体Reynolds数之间的关系。     

Immobilization of polyphenol oxidase on carboxymethylcellulose hydrogel beads: preparation and characterization

Carboxymethylcellulose (CMC) beads were prepared by a liquid curing method in the presence of trivalent ferric ions, and epicholorohydrin was covalently attached to the CMC beads. Polyphenol oxidase (PPO) was then covalently immobilized onto CMC beads. The enzyme loading was 603 µg g⁻¹ bead and the retained activity of the immobilized enzyme was found to be 44%. The K_m values were 0.65 and 0.87 mM for the free and the immobilized enzyme, and the V_max values were found to be 1890 and 760 U mg⁻¹ for the free and the immobilized enzyme, respectively. The optimum pH was 6.5 for the free and 7.0 for the immobilized enzyme. The optimum reaction temperature for the free enzyme was 40 °C and for the immobilized enzyme was 45 °C. Immobilization onto CMC hydrogel beads made PPO more stable to heat and storage, implying that the covalent immobilization imparted higher conformational stability to the enzyme. © 2000 Society of Chemical Industry     

Immobilization of metal nanoparticles on polyurethane membranes: synthesis and electrical properties

Ag and Cu nanoparticles were immobilized into crosslinked polyurethane (PU) membranes by taking advantage of the swelling characteristics of the membranes. The formation, shape and size of the nanoparticles inside the post‐swollen PU membranes were observed by transmission electron microscopy and atomic force microscopy. X‐ray diffraction indicated the presence of the pure Ag and Cu embedded in the amorphous PU matrix. Because of their compatibility, the nanoparticles improved the thermal stability and increased the glass transition temperature of PU. The membranes exhibited interesting conducting behavior with increasing temperature. The metal immobilization increased the ionic conductivity which further increased with temperature, with an activation energy of 0.15 eV indicating a thermally activated conduction mechanism. The optical and electrical properties of these starch‐based membranes can be utilized in the development of novel sensors for biomedical applications. Copyright © 2012 Society of Chemical Industry     

Polyorganophosphazene membranes: preparation and transport properties

Polyphenoxyphosphazene, polycumylphenoxyphosphazene, polybutylphenoxyphosphazene and their copolymers were synthesized. Asymmetric and homogeneous membranes for liquid-liquid and gas separations were prepared. The ultrafiltration membranes were characterized by a cut-off higher than 100,000 Daltons. The gas separation membranes, tested with O₂, N₂, CO₂ and CH₄, were characterized by permeabilities similar to the ones of rubbery polymers and selectivities similar to the ones of glassy polymers.     

High-strength ceramic based on zirconium dioxide: preparation and properties

Strength properties are considered for ZrO₂ hot-pressed ceramic materials stabilized with 4 – 6 wt.% Y₂O₃ in relation to original powder preparation method: solid phase synthesis, high-temperature salt thermolysis, combined hydroxide precipitation followed by freezing, drying and calcining, and the sol-gel method. Ceramic material with the highest strength in bending (up to 1350 MPa) are prepared from ZrO₂ – 5 wt.% Y₂O₃ powders, synthesized by coprecipitation of hydroxides followed by freezing.     

pH敏感聚合物微球的制备及其性能研究

通过原位聚合的方法制备了生物相容的、具有环境响应特性核壳型羟乙基纤维素／聚甲基丙烯酸(HEC／PMAA)聚合物微球。采用动态光散射法和荧光光谱法研究了HEC／PMAA聚合物微球的形成机理;采用红外光谱(FTIR)分析了微球中分子间相互作用;利用TEM观察了HEC／PMAA微球的形貌;考察了HEC／PMAA微球的pH敏感性能。     

Thermoresponsive microhydrogels: preparation,properties and applications

A microgel is a fascinating type of soft matter. Among the various microgels, great interest has been shown in microhydrogels because their functions are realized in water, which is the most benign liquid to humans. The microhydrogel‐composing polymers have their own delicate hydrophilic ? hydrophobic balance, which is sensitive to environmental conditions such as temperature, pH, ionic strength, light and specific (bio)molecules, in many cases. This review describes the methodology for the preparation of such microhydrogels, their properties, and finally their applications in physicochemical, biological and biomedical, optical and photonic, and chemical fields. The main material cited is a representative temperature‐sensitive polymer, poly(N‐isopropyl acrylamide), but some other environment‐friendly polymers such as cellulose derivatives are also reported. © 2013 Society of Chemical Industry     

医用黏合剂的制备及性能研究

以氰乙酸丁酯和多聚甲醛为主要原料,通过缩合、裂解反应合成了α-氰基丙烯酸丁酯单体,并制备了α-氰基丙烯酸酯医用黏合剂。着重探讨了增塑剂、固化促进剂(聚乙二醇二甲醚)对医用黏合剂柔韧性、固化速率和粘接力等影响,并对医用黏合剂的生化性能进行了表征。研究结果表明:当w(增塑剂)=10%、w(固化促进剂)=1.5%(均相对于混合物总质量而言)时,黏合剂的增韧效果相对最好、固化速率相对较大,并且其无溶血反应和无过敏反应,完全满足医用要求。     

一种壳聚糖基敷料的制备及其性能研究

近年来,临床上由于压疮、溃足等现象而导致伤口感染病例日益增加,而目前尚未有好的解决方法或是存在对应的"金标准"产品。在选用伤口敷料上具有潜力的天然高分子材料——壳聚糖,将其与一种力学性能优良、生物相容性好的聚合物P (LLA-CL)复合,通过静电纺丝技术制备了纳米纤维膜。经过一系列表征,该纳米纤维膜被证实具有纳米级的结构、微小的空隙、良好的力学性能以及较好的生物相容性,有望运用于伤口敷料。     

热塑性聚酰亚胺薄膜的制备与性能研究

以自制的双[4-(4-氨基苯氧基)苯基]砜(BAPS)、4,4′-二氨基二苯醚(ODA)和3,3′,4,4′-二苯醚四甲酸二酐(ODPA)为主要原料,采用共聚法合成了较高黏度的聚酰胺酸(PAA)溶液;然后该PAA溶液经高温酰亚胺化后,制得了TPI(热塑性聚酰亚胺)薄膜。研究结果表明:所有样品均具有较好的尺寸稳定性和较低的吸水率,并具有一定的热塑性;当n(BAPS)∶n(ODA)=50∶50时,相应的TPI薄膜具有相对最好的综合性能,其基本完成了酰亚胺化的转变过程,具有较好的耐热性[玻璃化转变温度(Tg)约为249℃,热失重10%时的温度约为510℃,800℃时的残炭率约为18%]和优异的电绝缘性能(介电常数为2.5、介电损耗为0.001 2和体积电阻率为2.3×10~(13)Ω·m)。     

Ni-Fe-SiC复合镀层的制备及性能研究

用电沉积的方法在含NiSO4及FeSO4的电解质溶液中制备了Ni-Fe-SiC复合镀层.通过正交试验,研究了Fe2 与Ni2 的浓度比、温度、pH和电流密度对镀层中SiC质量分数的影响,讨论了镀液中SiC含量与镀层显微硬度的关系,确定了最佳工艺条件为:c(Fe2 )/c(Ni2 )=0.09,镀液温度55 ℃,pH=3.0,电流密度1.8 A/dm2.在最佳工艺条件下所获得的复合镀层,显微硬度达650～850 HV,结合力和耐蚀性均良好.