氧化还原滴定测定含钌加氢催化剂的活性

设计了一套实验室加氢反应生成山梨醇的装置,用来测试含钌加氢催化剂的活性,比较了反应过程中温度、压力和搅拌速度对催化剂活性的影响.结果表明,测定含钌加氢催化剂的最佳条件为:温度在120℃～140℃之间,压力在3 MPa～4 MPa之间,搅拌速度在200 r/min～400 r/min之间.用氧化还原滴定法测定含钌加氢催化剂的活性是可行的,与国外原有的测试方法相比,测试温度和压力要低得多,且测试时间缩短.     

乙腈加氢制乙胺催化剂的研究

以水合肼和硼氢化钾为共还原剂制备了多元合金催化剂,将其用于乙腈催化加氢反应制乙胺。研究了催化剂活性组分和乙腈催化加氢工艺条件对催化剂性能的影响,并考察了该催化剂的稳定性。结果表明,含有稀土元素、Fe、Cu和Ni等组分的多金属催化剂具有良好的催化活性和选择性。在优化工艺条件(氢压1.5MPa,温度120℃,反应时间1h)下,乙腈转化率可达100%,乙胺收率达95%以上。     

Ni-Pd纳米涂层整体式催化剂加氢性能研究

采用浸涂法将自制的介孔空心SiO2纳米粉体涂覆到堇青石基体上,然后采用微波法负载活性组分Pd和助剂Ni制备了纳米涂层整体式加氢催化剂,并考察空速、涂层增重、Ni助剂添加量等因素对其乙炔选择性加氢催化性能的影响。结果表明:经过涂覆后的堇青石整体式催化剂加氢性能与未涂覆时相比有了显著提高,且添加适量的助剂Ni有助于催化性能的进一步改进。在反应温度为54℃、压力为0.1 MPa、空速为3 800 h-1的条件下,使用涂层增重质量分数为6%、Ni与Pd物质的量比为4∶1的催化剂,当乙炔接近完全转化时,乙烯选择性能够到达40.9%。     

Mn-Cu-La/TiO_2低温催化剂催化还原氮氧化物性能研究

采用浸渍法制备了Mn-Cu-La/TiO2催化剂,研究了其组分配比、焙烧温度等制备条件和NO进口浓度、空速、O2含量、NH3/NO摩尔比等操作条件对Mn-Cu-La/TiO2上NH3低温还原NO活性的影响;探讨了H2O、SO2对Mn-Cu-La/TiO2活性的影响.结果表明,该催化剂具有很好的低温SCR活性,空速为10 000h-1,反应温度为150℃下时NO转化率接近99.6%.180℃下同时通SO2、H2O后的360min内,活性始终保持在95%以上;单独通入SO2时,该催化剂较容易中毒;单独通入体积分数10%的H2O对催化剂活性基本没有影响,转化率始终保持在98%以上.     

液相硝基苯加氢Ni-Zr-B非晶态合金催化剂制备及结构表征

将化学还原法制备的Ni-Zr-B非晶态合金催化剂用于硝基苯液相加氢制苯胺的反应,并通过XRD,TEM和H2-TPD技术对催化剂进行表征,研究了Zr含量对Ni-Zr-B催化剂微观结构和其催化加氢性能的影响。结果表明,Ni-B非晶态合金催化剂表现出较高硝基苯转化率和苯胺选择性,Zr助剂的引入减小了催化剂非晶态结构短程有序范围和催化剂粒径,粒径由60nm减小至10nm左右;增多了Ni活性中心数,并减弱了Ni化学吸附氢强度,使得吸附的氢物种更易于在各吸附中心间迁移并参与反应,导致Ni-B非晶态合金催化硝基苯加氢的活性和选择性进一步提高。当Zr含量为8%时,催化剂具有最优的催化加氢性能,硝基苯转化率和苯胺选择性分别高达99.6%和100%。     

用化工软件研究碳二前加氢催化剂及其工艺

用Material Studio化工软件计算、研究了碳二前加氢催化剂及其工艺,结果证实α-Al2O3为适宜的碳二前加氢催化剂载体,Pd为适宜的主活性组分,Ag为适宜的助活性组分。确定的碳二前加氢催化剂的最佳使用温度为70℃,适当提高CO含量可以提高碳二前加氢催化剂的选择性。利用Material Studio软件可以进行碳二前加氢催化剂的制备设计及其使用工艺参数的优化计算。     

Co-Mo/ZSM-5的制备与加氢脱硫性能研究

采用Na_2CO_3溶液分别处理二氧化硅∶三氧化二铝物质的量比为50∶1、80∶1、150∶1的ZSM-5分子筛,采用XRD、SEM和NH3-TPD等进行表征。结果表明,经Na2CO3处理后,形成了微孔-介孔多级孔ZSM-5分子筛。在多级孔分子筛上负载Co、Mo制备Co-Mo/ZSM-5催化剂并进行加氢脱硫反应;研究了工艺条件对最佳催化剂加氢脱硫性能的影响。结果表明,二氧化硅∶三氧化二铝物质的量比为50∶1的催化剂加氢脱硫率最高;该催化剂在反应温度为350℃,压力3.0MPa,空速2.0h-1时,脱硫率达90.8%。     

微反应器制备镁铝尖晶石介孔材料及其性能评价

采用膜分散微反应器,利用共沉淀法研究镁铝尖晶石介孔材料的制备条件,考察合成条件对镁铝尖晶石纯度、晶粒尺寸、晶体相态和孔结构的影响,并成型得到Ni-Mo-MgAl_2O_4-γ-Al_2O_3催化剂;以质量分数为20%的小桐籽油为反应原料,在高温、高压加氢脱氧装置中对催化剂的加氢脱氧性能进行评价。结果表明:原料金属盐溶液浓度总和为0. 5 mol/L(其中镁、铝金属的物质的量比为1∶2)、反应pH为11、表面活性剂CTAB浓度为0. 001 mol/L、焙烧温度为1 000℃时,制备得到的镁铝尖晶石介孔材料具有较大的介孔面积和介孔体积;Ni-Mo-MgAl_2O_4-γ-Al_2O_3催化剂具有较大的比表面积和良好的机械稳定性、水热稳定性;在温度为360～390℃、压力为4. 0 MPa、空速为5. 0 h~(-1)、氢油质量比为200的工艺条件下,加氢脱氧油的收率大于79%。     

具有核壳结构的Ni／SiO2催化剂的制备及加氢性能研究

采用水热法制备了Ni3Si2O5（OH）4,在823K下通过氢气还原制备出了具有核壳结构Ni／SiO2催化剂,探讨以Ni／SiO2为催化剂,反应时间、温度、压力等因素对硝基苯液相加氢性能的影响,确定了硝基苯液相加氢适宜的条件,在该条件下硝基苯的转化率为97％,苯胺的选择性为99％。     

Pd-ZrO2/Al2O3催化剂对丙烯选择性催化还原NO的催化活性研究

采用浸渍法制备了具有高比表面积的氧化铝负载的Pd-ZrO2复合物催化剂(Pd-ZrO2/Al2O3),利用BET、XRD、TEM等手段研究了该复合物催化剂的物理特性,并重点研究了该复合物催化剂对以C3H6为还原剂选择性催化还原(SCR)NO的催化反应活性,分别讨论了反应温度、组分、焙烧温度、原料气组分、空速等因素对该催化反应的影响.结果发现,少量的Pd纳米粒子均匀分散于载体氧化铝上,添加适量ZrO2后,所制备的低负载量的Pd(1wt%)-ZrO2(2wt%)/Al2O3复合物催化剂具有较高的NO选择性催化还原反应活性,在240～250℃可使NO的转化率达到50%～70%.其活性提高的机制在于适量ZrO2的添加增强了反应物中NO和C3H6在催化剂表面的吸附,同时与Pd催化剂形成一种协同催化作用.     

MDA及其衍生物的制备和应用进展

本文简要介绍了MDA的制备及应用 ,并就其在作为固化剂或交联剂时存在的问题 ,介绍了几种可作为替代品的MDA衍生物及其制备和应用情况     

LP—15聚酰亚胺复合材料研究

ＬＰ－１５聚酰亚胺是新一代不含ＭＤＡ的ＰＲＭ聚酰亚胺树脂体系。作为复合材料树脂基体，ＬＰ－１５酰亚胺具有优异的成型工艺性，较 好的抗热氧化和稳定性，优良的综合学性能及耐冷热疲劳性能，可在２８０℃下替代ＰＭＲ－１５复合材料长期使用。     

LP-15 聚酰亚胺复合材料研究

LP-15 聚酰亚胺是新一代不含MDA 的PMR 聚酰亚胺树脂体系。作为复合材料树脂基体,LP-15 聚酰亚胺具有优异的成型工艺性, 较好的抗热氧化稳定性, 优良的综合力学性能及耐冷热疲劳性能, 可在280℃下替代PMR-15 复合材料长期使用。     

MDA improvement technique for lung counter measurements of uranium workers

A practical and simple method was employed to improve the minimum detectable activity (MDA) for lung counting measurements by summing several accumulated spectra. The method was checked for natural uranium, which produces peaks due to photon energies of 63.3, 92.6 and 185.7 keV. By combining nine measurements, an overall improvement of the MDA by a factor of about 3 was achieved. Uranium contamination levels lower than the MDA of a single spectrum could be detected with acceptable accuracy when analyzing the sum spectra. Specific results are given for four workers occupationally exposed to natural uranium.     

BMI/MDA/改性物B预聚体的反应性能

通过ＤＳＣ测试方法研究了４,４’－二氨基二苯甲烷及改性物Ｂ的含量对双马来酰亚胺树脂固化反应的影响。实验发现,随ＭＤＡ含量的增加,改性ＢＭＩ的固化反应温度大大降低;对于确定配比的ＢＭＩ／ＭＤＡ体系,随改性物Ｂ含量的减少,其反应活性越大,同时对形成这一结果的原因进行了讨论。     

Cure rate of DGEBA/MDA/GN/HQ system by differential scanning calorimetry analysis

To compare investigations of the cure kinetics of DGEBA/MDA/GN/HQ system by different methods, the fractional life method, Kissinger equation, Barrett method and integral method were used. From the fractional life method, reaction orders were between 0.77 and 0.93 but had no correlation with cure temperature, and from the Kissinger equation, the activation energy was 11.08 kcal mol⁻¹ and pre-exponential factor was 2.78×10³ s⁻¹. For the second-order reaction by the Barrett method and integral method, the activation energy was 20 kcal mol⁻¹ and the pre-exponential factor was 8.5×10⁸ s⁻¹. By comparison of the Barrett model with experimental data, it was found that the Barrett model was useful for predicting the cure time at a given temperature.     

一种新的Presence建模方法

在分析Presence信息特征的基础上,提出了Presence模型的建模需求和功能目标,并指出:信息共享、隐私保护以及信息融合要求对信息提供一致的管理方式,可通过建立Presence信息模型来解决这一问题,信息模型的建立应该直观和易用.根据建模需求对适用的建模方法进行了比较,建立了一种新的面向普通应用开发者的混合建模方法,结合图形化建模和本体建模的优点,在建模过程引入了模型驱动结构(MDA)方法和工程化思想,标准化的表达方式和规范的建模步骤保证了建模的质量.     

Health risk assessment by measuring plasma malondialdehyde (MDA), urinary 8-hydroxydeoxyguanosine (8-OH-dG) and DNA strand breakage following metal exposure in foundry workers

Silica particles and metals are important occupational hazards in foundry workers, and exposure may result in DNA damage and lipid peroxidation through oxidative stress. This study aimed to compare oxidative damage by measuring the levels of plasma malondialdehyde (MDA), urinary 8-hydroxydeoxyguanosine (8-OH-dG) and DNA strand breakage in workers at two foundry plants (exposure group) and in town hall employees (control group) in central Taiwan. Air samples for metals analysis in the workplace were also collected to assess the health risk to foundry workers.Significantly higher MDA levels (4.28 μM versus 1.64 μM), DNA strand breakage (6.63 versus 1.22), and 8-OH-dG levels (5.00 μg/g creatinine versus 1.84 μg/g creatinine) were found in exposure group compared with the control group. Higher levels of these parameters were also found in workers involved in manufacturing than in workers involved in administration. Higher air respirable dust concentrations were found in manufacturing departments (0.99 mg/m³) than in administrative departments (0.34 mg/m³). The health risk assessment on metals exposure showed that the cancer risk for Cd, Cr and Ni were all above 1 × 10⁻⁶. Future studies are necessary to determine whether metals exposure can contribute to oxidative damage in foundry workers.     

Characterisation of sol–gel method synthesised MgZnFe2 O4 nanoparticles and its cytotoxic effects on breast cancer cell line,MDA MB‐231 in vitro

In this study, nanocrystalline magnesium zinc ferrite nanoparticles were successfully prepared by a simple sol–gel method using copper nitrate and ferric nitrate as raw materials. The calcined samples were characterised by differential thermal analysis/thermogravimetric analysis, Fourier transform infrared spectroscopy and X‐ray diffraction. Transmission electron microscopy revealed that the average particle size of the calcined sample was in a range of 17–41 nm with an average of 29 nm and has spherical size. A cytotoxicity test was performed on human breast cancer cells (MDA MB‐231) and (MCF‐7) at various concentrations starting from (0 µg/ml) to (800 µg/ml). The sample possessed a mild toxic effect toward MDA MB‐231 and MCF‐7 after being examined with MTT (3‐[4, 5‐dimethylthiazol‐2‐yl]‐2, 5 diphenyltetrazolium bromide) assay for up to 72 h of incubation. Higher reduction of cells viability was observed as the concentration of sample was increased in MDA MB‐231 cell line than in MCF‐7. Therefore, further cytotoxicity tests were performed on MDA MB‐231 cell line.Inspec keywords: sol‐gel processing, nanoparticles, nanofabrication, magnesium compounds, zinc compounds, toxicology, biological organs, cancer, cellular biophysics, nanomedicine, calcination, differential thermal analysis, Fourier transform infrared spectra, X‐ray diffraction, transmission electron microscopy, particle size, organic compoundsOther keywords: sol‐gel method, cytotoxic effects, breast cancer cell line, MDA MB‐231 in vitro, nanocrystalline magnesium zinc ferrite nanoparticles, copper nitrate, ferric nitrate, raw materials, calcined samples, differential thermal analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy, X‐ray diffraction, transmission electron microscopy, average particle size, cytotoxicity testing, human breast cancer cells, mild toxic effect, 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5 diphenyltetrazolium bromide) assay, cell viability, MCF‐7, MDA MB‐231 cell line, size 17 nm to 41 nm