检索结果-南通市图书馆

Effects of synthesis methods on the performance of Pt + Rh/Ce_(0.6)Zr_(0.4)O_2 three-way catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第3期26卷 683-693页

作者： Zongcheng Zhan liyun song Xiaojun Liu Jiao Jiao Jinzhou Li Hong He Laboratory of Catalysis Chemistry and Nano-Science Department of Chemistry and Chemical Engineering College of Environmental and Energy Engineering Beijing University of Technology

The 0.7 wt% Pt ＋ 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts were fabricated via different methods, including ultrasonic-assisted membrane reduction （UAMR） co-precipitation, UAMR separation precipitation, co-impregnation, and sequential impregnation. The catalysts were physico-chemically characterized by N2 adsorption, XRD, TEM, and Hz-TPR techniques, and evaluated for three-way catalytic activities with simulated automobile exhaust. UAMR co-precipitation- and UAMR separation precipitation- prepared catalysts exhibited a high surface area and metal dispersion, wide λ window and excellent conversion for NOx reduction under lean conditions. Both fresh and aged catalysts from UAMR- precipitation showed the high surface areas of ca. 60-67 m^2/g and 18-22 m^2/g, respectively, high metal dispersion of 41%-55%, and small active particle diameters of 2.1-2.7 nm. When these catalysts were aged, the catalysts prepared by the UAMR method exhibited a wider working window （△λ = 0.284--0.287） than impregnated ones （△λ = 0.065-0.115） as well as excellent three-way catalytic performance, and showed lower/so （169℃） and T90 （195℃） for NO reduction than the aged catalysts from impregnation processes, which were at 265 and 309℃, respectively. This implied that the UAMR-separation precipitation has important potential for industrial applications to improve catalytic performance and thermal stability. The fresh and aged 0.7 wt% Pt ＋ 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts prepared by the UAMR-separation precipitation method exhibited better catalytic performance than the corresponding catalysts prepared by conventional impregnation routes.

关键词： UAMRthree way catalyst Pt and Rh nanoparticles precipitation thermal stability

Clinical Observation of Disposal Uterine Cavity Observation and Suction Surgery System on Terminating Pregnancy in Very Early Pregnancy

在线全文

学校读者我要写书评

暂无评论

International Journal of Clinical Medicine 2023年第11期14卷 449-456页

作者： Qi Wu Suning Bai Wenfei Wu liyun song Lina Han Department of Gynecology Hebei General Hosipital Shijiazhuang China

Objective: To compare the clinical effects of uterine cavity observation and suction surgery system with ultrasound guided induced abortion in very early pregnancy induced abortion surgery. Method: Select 80 patients who requested termination of pregnancy due to early pregnancy from August 2022 to April 2023, and analyze the data. 40 patients who underwent ultrasound-guided induced abortion to terminate pregnancy were included in the control group, and 40 patients who underwent uterine cavity observation surgery to terminate pregnancy were included in the observation group. Compare the surgical time, number of times the straw enters the uterine cavity, incidence of complications, and menstrual recovery time between the two groups. Results: There was no statistically significant difference in the surgical time between the observation group and the control group, but the number of times negative pressure straws entered the uterine cavity and the incidence of surgical complications in the observation group were significantly lower than those in the control group (P Conclusion: Applying the uterine cavity observation and suction surgical system to terminate pregnancy in very early pregnancy has the advantages of minimal damage to the uterus and low incidence of surgical complications, greatly protecting the patient’s fertility.

关键词： Uterine Cavity Observation Suction Surgery Ultrasound-Guided Induced Abortion Clinical Observation of Early Pregnancy

In-situ DRIFT assessment on strengthening effect of cerium over FeO_(x)/TiO_(2)catalyst for selective catalytic reduction of NO_(x) with NH_(3)

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2021年第5期39卷 526-531页

作者： Hossein Chitsazi Ningqiang Zhang Lingcong Li Xiaojun Liu Rui Wu Junda He liyun song Hong He Beijing Key Laboratory for Green Catalysis and Separation and Key Laboratory of Beijing on Regional Air Pollution Control Beijing University of TechnologyBeijing 100124China College of Chemistry Chemical Engineering and Materials ScienceInstitute of Molecular and Nano ScienceShandong Normal UniversityJinan 250014China Collaborative Innovation Center of Electric Vehicle in Beijing Beijing 100081China

Fe-based catalysts have a great potential to be used for selective catalytic reduction(SCR)of NO_(x)with NH3 reaction due to their low cost,nontoxicity and excellent catalytic activity.The aim of this paper is to investigate Ce doping effect on activity of NH_(3)-SCR over the FeO_(x)/TiO_(2)catalyst.In-situ diffuse reflectance infrared fourier transform(DRIFT)technology was utilized to verity the adsorbed species on the surface of FeO_(x)/TiO_(2)and FeO_(x)-CeO_(2)/TiO_(2)catalysts.With respect to the obtained results,among the four catalysts studied,the FeO_(x)-CeO_(2)/TiO_(2)with the FeO_(x)/CeO_(2)ratio of 3/8 shows the best NO conversion more than 98%in the temperature range of 230—350℃,The active centers for NH_(3)adsorption and activation are assigned to Lewis acid sites over the FeO_(x)-CeO_(2)/TiO_(2)and monodentate nitrates can act as the key intermediate in the NH3-SCR.Moreover,both of Langmuir-Hinshelwood and Eley-Rideal mechanisms are observed over the FeO_(x)-CeO_(2)/TiO_(2)catalysts in the SCR.

关键词： Fe-based catalysts Ce doping Selective catalytic reduction In-situ DRIFT Rare earths

Use of rare earth elements in single-atom site catalysis:A critical review——Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2021年第3期39卷 233-242,I0001页

作者： Ningqiang Zhang Han Yan Lingcong Li Rui Wu liyun song Guizhen Zhang Wenjun Liang Hong He Key Laboratory of Beijing on Regional Air Pollution Control and Beijing Key Laboratory for Green Catalysis and Separation Beijing University of TechnologyBeijing 100124China Department of Chemistry Tsinghua UniversityBeijing 100084China Collaborative Innovation Center of Electric Vehicles in Beijing Beijing 100081China

Rare earth metals are strategic resources with potential applications in optics,metallurgy and catalysis.In recent years,single-atom site catalysts(SASCs) have attracted increasing attention owing to their 100%atom efficiency and unique catalytic performances.Over the past decade,rare earth elements,including rare earth metals and their oxides,have shown great potential in SASCs.However,systematic analyses of data are still handful.In this mini-review,the use of rare earth metals and their oxides in SASCs was summarized and the results are discussed.A particular focus was paid to the synthetic strategies,characterization of rare earth-containing SASCs,and applications as catalysis supports,promoters and active sites.Current issues faced by rare-earth metals and their oxides in SASCs,as well as future prospects were also provided.

关键词： Rare earth catalysis Single-atom site catalysis Synthetic strategies Characterization Applications

Promoting effect of microwave irradiation on CeO2-TiO2 catalyst for selective catalytic reduction of NO by NH3

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2020年第1期38卷 59-69页

作者： Jie Cheng liyun song Rui Wu Shining Li Yanming Sun Hongtai Zhu Wenge Qiu Hong He Key Laboratory of Beijing on Regional Air Pollution Control And Beijing Key Laboratory for Green Catalysis and SeparationBeijing University of TechnologyBeijing 100124China Collaborative Innovation Centre of Electric Vehicles in Beijing Beijing 100081China

In this work we prepared several CeO2-TiO2 catalysts for the NH3-SCR reactionusing co-precipitation with assistance of microwave irradiation.The catalytic NH3-SCR activities over CeO2-TiO2 catalysts at low temperatures are largely enhanced by the treatment of microwave irradiation,the operation temperature window is also broadened.For better understanding the promotion mechanism,the catalyst prepared by conventional co-precipitation with and without microwave irradiation treatment was characterized with H2-TPR,NH3-TPD,XPS,XRD and BET.Microwave irradiation treatment accelerates the crystallite rate of CeO2-TiO2 catalysts,and greatly enlarges their surface area by adjusting their microstructures.The resistance to SO2 and H2O is also improved via regulating the hierarchical pore structure by the microwave irradiation.Microwave irradiation treatment can also improve the redox property and increase the acid sites over the catalyst surfaces.The result of in situ DRIFTS suggests that the microwave irradiation treatment generates more Br?nsted acid sites on CeO2-TiO2-2 h catalyst,helpful in SCR reactions.XPS results show that after microwave irradiation on the CeO2-TiO2 catalysts,the surface demonstrates an elevated concentration of chemisorbed oxygen,consequently leading to better oxidation of NO to NO2.Additionally,the molar ratio of Ce3+/Ce4+has been elevated after being treated by microwave irradiation,a vital factor in enhancing the NH3-SCR activities.

关键词： SCR catalyst NH3-SCR Low temperature CeO2-TiO2 Microwave irradiation Rare earths

NiB_(2)O_(4)(B=Mn or Co)catalysts for NH_(3)-SCR of NO_(x) at low-temperature in microwave field

在线全文

学校读者我要写书评

暂无评论

环境科学与工程前沿(英文) 2023年第8期17卷 57-67页

作者： liyun song Shilin Deng Chunyi Bian Cui Liu Zongcheng Zhan Shuangye Li Jian Li Xing Fan Hong He Key Laboratory of Beijing on Regional Air Pollution Control Beijing Key Laboratory for Green Catalysis and SeparationBeijing University of TechnologyBeijing 100124China Qingdao Huashijie Environment Technology Co. Ltd.Qingdao 266510China

Microwave-assisted selective catalytic reduction of nitrogen oxides(NOx)was investigated over Nibased metal oxides.The NiMn2O4 and NiCo_(2)O_(4) catalysts were synthesized by the co-precipitation method and their activities were evaluated as potential candidate catalysts for low-temperature NH_(3)-SCR in a microwave field.The physicochemical properties and structures of the catalysts were characterized by X-ray diffraction(XRD),Scanning electron microscope(SEM),N_(2)-physisorption,NO adsorption-desorption in the microwave field,H2-temperature programmed reduction(H2-TPR)and NH3-temperature programmed desorption(NH_(3)-TPD).The results verified that microwave radiation reduced the reaction temperature required for NH_(3)-SCR compared to conventional heating,which needed less energy.For the NiMn_(2)O_(4) catalyst,the catalytic efficiency exceeded 90%at 70°C and reached 96.8%at 110°C in the microwave field.Meanwhile,the NiMn_(2)O_(4) also exhibited excellent low-temperature NH3-SCR reaction performance under conventional heating conditions,which is due to the high BET specific surface area,more suitable redox property,good NO adsorption-desorption in the microwave field and rich acidic sites.

关键词： Microwave field Spinel oxides NO_(x) Selective catalytic reduction

Five trends of China's pharmaceutical industry in 2022

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

药学学报:英文版 2023年第6期13卷 2812-2814页

作者： Yue Chen Jianing song Yihang Cui liyun Zhou Pharmcube(Beijing)Co. Ltd.Beijing 100020China Dongzhimen Hospital Beijing University of Chinese MedicineBeijing 100700China

In recent years, China has started to encourage pharmaceutical enterprises to carry out research and development of innovative drugs.From 2018 to 2021, with the capital rapidly influx into the pharmaceutical industry, there were increasing numbers of financing events with growing amount year by year1. The rapid development of China's pharmaceutical industry in the past five years is also accompanied by bubbles.

关键词： enterprises industry carry

在线全文

学校读者我要写书评

暂无评论

血清信号素3A在类风湿关节炎的诊断价值

中国医药指南 2024年第6期22卷 5-8页

作者：宋丽云宋丽青戴薇曾频频谭立明南昌大学第二附属医院检验科江西省检验医学重点实验室南昌330008 赣州市人民医院检验科赣州341000 赣州市人民医院急诊科赣州341000

目的通过检测血清信号素3A(Sema3A)在类风湿关节炎(RA)中的表达水平,探讨其对RA的诊断价值。方法随机选取到赣州市人民医院就诊者并分为三组:(1)RA组(病情活动性RA 51例,病情非活动性RA 52例)。(2)非RA组患者93例。(3)健康对照组(HC)50... 详细信息

目的通过检测血清信号素3A(Sema3A)在类风湿关节炎(RA)中的表达水平,探讨其对RA的诊断价值。方法随机选取到赣州市人民医院就诊者并分为三组:(1)RA组(病情活动性RA 51例,病情非活动性RA 52例)。(2)非RA组患者93例。(3)健康对照组(HC)50例。采用酶联免疫吸附法(ELISA)检测血清中Sema3A、抗环瓜氨酸多肽抗体(anti-CCP)和抗RA33抗体(anti-RA33);散射比浊法检测类风湿因子(RF)和C-反应蛋白(CRP);魏氏法检测红细胞沉降率(ESR)。结果RA组血清Sema3A、anti-CCP、RF和anti-RA33表达水平分别为(27.15±8.19)ng/ml、131.31(399.50)U/ml、105.90(167.50)U/ml和30.80(23.80)U/ml,与非RA组和HC组比较,结果具有统计学差异。Sema3A对RA诊断的曲线下面积为0.76,标准误为0.03,95%可信区间(95%CI)为0.70~0.82。ROC曲线分析各项指标对RA的诊断显示,特异度最高的是anti-CCP(Sp=0.92),灵敏度最高的是RF(Se=0.83),约登指数和曲线下面积最高的是anti-CCP(YDI=0.73,AUC=0.85)。RA病情活动组和非活动组血清Sema3A水平比较具有统计学差异(P<0.01),血清Sema3A与ESR、CRP、DAS28均呈负相关(r=-0.54,r=-0.66,r=-0.42,P<0.01)。结论Sema3A对RA患者具有良好诊断价值,与非RA患者比较具有鉴别诊断价值,且可以用来判断RA疾病的严重程度。

关键词：类风湿关节炎诊断信号素3A 抗环瓜氨酸多肽抗体类风湿因子抗RA33抗体

Dynamically modulated synthesis of hollow metal-organic frameworks for selective hydrogenation reactions

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第8期16卷 11334-11341页

作者： liyun Xiao Chuanqi Cheng Zhixi Li Chaoyang Zheng Jing Du Meina song Yue Wan Shaopeng Li Guo Jun Meiting Zhao Department of Chemistry Institute of Molecular Aggregation ScienceTianjin Key Laboratory of Molecular Optoelectronic SciencesTianjin UniversityTianjin 300072China Institute of New Energy Materials School of Materials Science and EngineeringTianjin UniversityTianjin 300072China State Key Laboratory of Separation Membranes and Membrane Processes School of ChemistryTiangong UniversityTianjin 300387China

Hollow metal-organic frameworks(MOFs)have attracted increasing attention in the field of catalysis in recent years due to their unique cavity structure with fast mass-diffusion rates and easily accessible active sites.Here,we report the use of dynamic modulators,which are formed by the in-situ imine condensation reaction of 4-aminobenzoic acid and 4-formylbenzoic acid,to regulate the growth of MOFs to synthesize well-defined hollow thioether functionalized UiO-67(denoted as H-UiO-67-S)single crystals.After supporting Pd nanoparticles,the designed catalysts Pd@H-UiO-67-S show excellent conversion(>99.9%),selectivity(>99.9%),and stability(10 cycles)in the selective hydrogenation of nitrobenzenes with other reducible groups.Density functional theory calculations and the experimental results reveal that Pd nanoparticles not only selectively adsorb the nitro-groups on nitrobenzene,but also restrict the adsorption of the aniline product,due to the interaction of thioether with Pd in the confined pores of H-UiO-67-S,finally result in a significant increase in selectivity of nitro-hydrogenation.

关键词： hollow structure metal-organic frameworks(MOFs) dynamically modulated synthesis selective hydrogenation nitrobenzene