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Effects of Na+on Cu/SAPO-34 for ammonia selective catalytic reduction

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Journal of Environmental Sciences 2018年第8期30卷 20-28页

作者： Can Wang Chen Wang Jun Wang Jianqiang Wang Meiqing Shen Wei Li Key laboratory for Green Chemical Technology of State Education Ministry School of Chemical Engineering&TechnologyTianjin UniversityTianjin 300350China. School of Environment and Safety Engineering North University of ChinaTaiyuan 030051China Collaborative Innovation Centre of Chemical Science and Engineering(Tianjin) Tianjin 300350China State Key laboratory of Engines Tianjin UniversityTianjin 300350China General Motors global research and Development Chemical Sciences and Materials Systems Lab30500 Mound RoadWarrenMI 48090USA

Copper-exchanged chabazite（Cu/CHA） catalysts have been found to be affected by alkali metal and alkaline earth ions. However, the effects of Na＋ ions on Cu/SAPO-34 for ammonia selective catalytic reduction（NH_3-SCR） are still unclear. In order to investigate the mechanism, five samples with various Na contents were synthesized and characterized. It was observed that the introduced Na＋ ion-exchanges with H＋and Cu2＋of Cu/SAPO-34. The exchange of H＋is easier than that of isolated Cu2＋. The exchanged Cu2＋ions aggregate and form ＂CuAl_2O4-like＂ *** NH_3-SCR activity of Cu/SAPO-34 decreases with increasing Na content, and the loss of isolated Cu2＋and acid sites is responsible for the activity loss.

关键词： Cu/SAPO-34 Ammonia selective catalytic reduction (NH3-SCR) Na effects Ion-exchange

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Surface modification of blue TiO2 with silane coupling agent for NOx abatement

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Progress in Natural Science:Materials International 2021年第2期31卷 230-238页

作者： Adriana Martinez-Oviedo Yuwaraj K.Kshetri Bhupendra Joshi Soo Wohn Lee Department of Environmental and Bio-Chemical Engineering Sun Moon University research Center for Eco Multifunctional Nanomaterials Sun Moon University Department of Fusion Science and Technology Sun Moon University

The role of hydroxyl-functionalization of reduced TiO2（Blue TiO2） for the photocatalytic oxidation of toxic NOx was systematically explored in the present study. A hydrogenation technique was used to reduce the rutile phase in P25 TiO2giving rise to a Magneli phase. Then, the process was followed by the surface functionalization of the Blue TiO2with Trimethoxy（Propyl） Silane（TPS）. The fabricated nanoparticles were structurally characterized,and photocatalytically tested for NOx abatement. OH-functionalized Blue TiO2showed strong photo-oxidation of NOx with NOx removal efficiency of 80.2%. The broad-band light absorption（UV and visible） and the formation of a higher number of radicals on the surface of OH-functionalized Blue TiO2made the material more efficient than other samples. In addition, the lowest NO2selectivity of 2.7% proved the effective suppression of toxic NO2and formation of nitrate ions. The reusability test was carried out for five cycles of 1 h and had 10% loss in NOx removal efficiency. The role of surface OH groups for the oxidation of NO and NO2has been discussed in this manuscript. A possible mechanism for NOx photo-oxidation is proposed based on FTIR, ESR, and ion chromatography test.

关键词： Blue TiO2 OH-Functionalization NOx Photo-oxidation Hydroxyl radicals

Near-resonance enhanced label-free stimulated Raman scattering microscopy with spatial resolution near 130 nm

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Light(Science & Applications) 2018年第1期7卷 279-288页

作者： Yali Bi Chi Yang Yage Chen Shuai Yan Guang Yang Yaozu Wu Guoping Zhang Ping Wang Britton Chance Center for Biomedical Photonics Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and TechnologyWuhanHubei 430074China MoE Key laboratory for Biomedical Photonics Collaborative Innovation Center for Biomedical EngineeringSchool of Engineering SciencesHuazhong University of Science and TechnologyWuhanHubei 430074China MoE Key laboratory of Quark and Lepton Physics and College of Physics Science and Technology Central China Normal UniversityWuhan 430079China

High-resolution optical microscopes that can break 180 nm in spatial resolution set to conventional microscopies are much-needed ***,current optical microscopes have to rely on exogenous fluorescent labels to achieve high resolution in biological ***,we report near-resonance enhanced label-free stimulated Raman scattering(SRS)microscopy with a lateral resolution near 130 nm,in which the high-resolution image contrast originates directly from a low concentration of endogenous biomolecules,with sensitivity gains of approximately 23 ***,by using a 0.3-m-long optical fiber,we developed hyperspectral SRS microscopy based on spectral focusing *** to enhancements in spatial resolution and sensitivity,we demonstrated highresolution imaging of three-dimensional structures in single cells and high-resolution mapping of large-scale intact mouse brain tissues in *** using enhanced high-resolution hyperspectral SRS,we chemically observed sphingomyelin distributed in the myelin sheath that insulates single *** concept opens the door to biomedical imaging with~130 nm resolution.

关键词： resolution resonance approximate

Counterfactual analysis of the 2023 Omicron XBB wave in China

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Infectious Disease Modelling 2024年第1期9卷 195-203页

作者： Hengcong Liu Xiangyanyu Xu Xiaowei Deng Zexin Hu Ruijia Sun Junyi Zou Jiayi Dong Qianhui Wu Xinhua Chen Lan Yi Jun Cai Juanjuan Zhang Marco Ajelli Hongjie Yu School of Public Health Fudan UniversityKey Laboratory of Public Health SafetyMinistry of EducationShanghaiChina laboratory for Computational Epidemiology and Public Health Department of Epidemiology and BiostatisticsIndiana University School of Public HealthBloomingtonINUSA

Background:China has experienced a COVID-19 wave caused by Omicron XBB variant starting in April *** aim is to conduct a retrospective analysis exploring the dynamics of the outbreak under counterfactual scenarios that combine the use of vaccines,antiviral drugs,and nonpharmaceutical ***:We developed a mathematical model of XBB transmission in China,which has been calibrated using SARS-CoV-2 positive rates per *** age-specific infection-hospitalization risk,infection-ICU risk,and infection-fatality risk were used to estimate disease burdens,characterized as number of hospital admissions,ICU admissions,and ***:We estimated that in absence of behavioral change,the XBB outbreak in spring 2023 would have resulted in 0.86 billion infections(∼61%of the total population).Our counterfactual analysis shows that the synergetic effect of vaccination(70%vaccination coverage),antiviral treatment(20%receiving antiviral treatment),and moderate nonpharmaceutical interventions(20%isolation and L1 PHSMs)could reduce the number of deaths to levels close to seasonal influenza(1.17 vs.0.65 per 10,000 individuals and 5.85 vs.3.85 per 10,000 individuals aged 60+,respectively).The maximum peak prevalence of hospital and ICU admissions are estimated to be lower than the corresponding capacities(8.6 vs.10.4 per 10,000 individuals and 1.2 vs.2.1 per 10,000 individuals,respectively).Conclusion:Our findings suggest that the capacity of the Chinese healthcare system was adequate to face the Omicron XBB wave in spring 2023 but,at the same time,supports the importance of administering highly effective vaccine with long-lasting immune response,and the use of antiviral treatments.

关键词： wave analysis starting

Long-lived electron emission reveals localized plasmon modes in disordered nanosponge antennas

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Light(Science & Applications) 2017年第1期6卷 458-465页

作者： Germann Hergert Jan Vogelsang Felix Schwarz Dong Wang Heiko Kollmann Petra Groß Christoph Lienau Erich Runge Peter Schaaf Carl von Ossietzky Universität Institut für PhysikCenter of Interface ScienceD-26129 OldenburgNiedersachsenGermany Technische Universität Ilmenau Institut für Physik and Institut für Mikro-und Nanotechnologien MacroNano®D-98693 IlmenauThüringenGermany Technische Universität Ilmenau Institut für Mikro-und Nanotechnologien MacroNano®and Institut für WerkstofftechnikFachgebiet Werkstoffe der ElektrotechnikD-98693 IlmenauThüringenGermany Forschungszentrum Neurosensorik Carl von Ossietzky UniversitätD-26111 OldenburgNiedersachsenGermany

We report long-lived,highly spatially localized plasmon states on the surface of nanoporous gold nanoparticles—nanosponges—with high excitation *** is well known that disorder on the nanometer scale,particularly in two-dimensional systems,can lead to plasmon localization and large field enhancements,which can,in turn,be used to enhance nonlinear optical effects and to study and exploit quantum optical ***,we introduce promising,three-dimensional model systems for light capture and plasmon localization as gold nanosponges that are formed by the dewetting of gold/silver bilayers and *** study light-induced electron emission from single nanosponges,a nonlinear process with exponents of n≈5...7,using ultrashort laser pulse excitation to achieve femtosecond time *** long-lived electron emission process proves,in combination with optical extinction measurements and finite-difference time-domain calculations,the existence of localized modes with lifetimes of more than 20 *** electrons couple efficiently to the dipole antenna mode of each individual nanosponge,which in turn couples to the ***,individual gold nanosponges are cheap and robust disordered nanoantennas with strong local resonances,and an ensemble of nanosponges constitutes a meta material with a strong polarization independent,nonlinear response over a wide frequency range.

关键词： disorder-induced plasmon localization nanoantennas nanoporous gold nanoparticles ultrafast photoemission spectroscopy

5-Methylcytosine RNA Methylation in Arabidopsis Thaliana

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Molecular Plant 2017年第11期10卷 1387-1399页

作者： Xuean Cui Zhe Liang Lisha Shen Qian Zhang Shengjie Bao Yuke Geng Bin Zhang Vonny Leo Leah A. Vardy Tiegang Lu Xiaofeng Gu Hao Yu Biotechnology research Institute Chinese Academy of Agricultural Sciences Beijing 100081 China Department of Biological Sciences and Temasek Life Sciences laboratory National University of Singapore 117543 Singapore Singapore Institute of Medical Biology Agency for Science Technology and Research (A^+STAR) 8A Biomedical Grove #06-06 Immunos 138648 Singapore Singapore

5-Methylcytosine （m^5C） is a well-characterized DNA modification, and is also predominantly reported in abundant non-coding RNAs in both prokaryotes and eukaryotes. However, the distribution and biological functions of m^5C in plant mRNAs remain largely unknown. Here, we report transcriptome-wide profiling of RNA m^5C in Arabidopsis thaliana by applying m^5C RNA immunoprecipitation followed by a deep- sequencing approach （m^5C-RIP-seq）. LC-MS/MS and dot blot analyses reveal a dynamic pattern of m^5C mRNA modification in various tissues and at different developmental stages, m^5C-RIP-seq analysis identified 6045 m^5C peaks in 4465 expressed genes in young seedlings. We found that m^5C is enriched in coding sequences with two peaks located immediately after start codons and before stop codons, and is associated with mRNAs with low translation activity. We further demonstrated that an RNA （cytosine-5）-methyl- transferase, tRNA-specific methyltransferase 4B （TRM4B）, exhibits m^5C RNA methyltransferase activity. Mutations in TRM4B display defects in root development and decreased m^5C peaks. TRM4B affects the transcript levels of the genes involved in root development, which is positively correlated with their mRNA stability and m^5C levels. Our results suggest that m^5C in mRNA is a new epitranscriptome marker inArabidopsis, and that regulation of this modification is an integral part of gene regulatory networks underlying plant development.

关键词： 5-methylcytosine (m^5C) Arabidopsis RNA methylation TRM4B root development

Scale-up of a high shear wet granulation process using a nucleation regime map approach

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Particuology 2017年第2期15卷 87-94页

作者： Gan Luo Bing Xu Yi Zhang Xianglong Cui Jianyu Li Xinyuan Shi Yanjiang Qiao research Center of Traditional Chinese Medicine Information Engineering Beijing University of Chinese Medicine Beijing 100029 China Institute of Chinese Materia Medica China Academy of Chinese Medical Science Beijing 100700 China Beijing Key laboratory of Traditional Chinese Medicine Manufacturing Process Control and Quality Evaluation Beijing Municipal Science & Technology Commission Beijing 100029 China

Scale-up of the high shear wet granulation （HSWG） process is considered a challenge because HSWG is complex and influenced by numerous factors, including equipment, formulation, and process variables. For a system of microcrystalline cellulose and water, HSWG experiments at three scales （1, 2, and 4 L working vessel） were conducted with a granulator. Scale-up was implemented on the basis of a nucleation regime map approach. To keep dimensionless spray flux and drop penetration time constant, water addition time at three processing scales were 300, 442, and 700 s, respectively. The other process parameters were kept unchanged. Granule size distributions were plotted and compared, and scanning electron microscopy was used to analyze granule surface morphology. Physical characterization was undertaken using a modified SeDeM method. At nearly all scales, granule yield was greater than 85% and all the cosine values were larger than 0.89. At the same experiment points, granules at all scales had similar surface morphology and similar physical characteristics. The results demonstrate that a rational scaling-up of the HSWG process is feasible using a regime map approach.

关键词： High shear wet granulation Quality by design Regime map Scale-up Microcrystanine cellulose

Flexible and stretchable metal oxide gas sensors for healthcare

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Science China(Technological Sciences) 2019年第2期62卷 209-223页

作者： ZHENG XiaoQi CHENG HuanYu Department of Engineering Science and Mechanics The Pennsylvania State University University Park School of Physical Science and Technology ShanghaiTech University Materials research Institute the Pennsylvania State University University Park

Capable of measuring volatile biomarker produced by the metabolism from several secretion pathways, flexible and stretchable metal oxide gas sensors have received increasing attention and their development for healthcare starts to gain *** of semiconducting metal oxide on a soft, thin, flexible substrate is the key to enable the flexible property to the gas sensor and such integration typically involves either a direct growth or post transfer of the metal oxide on or to the flexible substrate. In addition to the planar plastic substrate, textile represents another important class of flexible substrates due to its ease of integration with clothing. Moreover, the integration of metal oxide on a single fiber provides a great versatility for different applications. Though flexible sensors can easily conform to the developable surface(e.g., cylinder or cone) from a bending deformation, the conformal contact between the sensor and the tissue surface that is often non-developable requires the sensor to be capable of stretching. Due to the intrinsically brittle nature of the semiconducting metal oxide, several stretchable structures have been explored. Despite the great strides made to the burgeoning area of flexible and stretchable metal oxide gas sensors,grand challenges still need to be overcome before the technology can be applied for the practical application. The selected challenges discussed in this mini-review also represent a fraction of possibilities and opportunities for the research community in the future.

关键词： metal oxide gas sensor flexible and stretchable properties structural design strategies volatile biomarker

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Observing charge separation in nanoantennas via ultrafast point-projection electron microscopy

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Light(Science & Applications) 2018年第1期7卷 532-539页

作者： Jan Vogelsang Germann Hergert Dong Wang Petra Groß Christoph Lienau Carl von Ossietzky Universität Institut für Physik and Center of Interface Science26129 OldenburgNiedersachsenGermany TU Ilmenau Institut für Werkstofftechnik und Institut für Mikro-und Nanotechnologien98693 IlmenauThüringenGermany Carl von Ossietzky Universität Forschungszentrum Neurosensorik26129 OldenburgNiedersachsenGermany Department of Physics Lund UniversityBox 11822100 LundSweden

Observing the motion of electrons on their natural nanometer length and femtosecond time scales is a fundamental goal of and an open challenge for contemporary ultrafast science1–*** present,optical techniques and electron microscopy mostly provide either ultrahigh temporal or spatial resolution,and microscopy techniques with combined space-time resolution require further development6–*** this study,we create an ultrafast electron source via plasmon nanofocusing on a sharp gold taper and implement this source in an ultrafast point-projection electron *** source is used in an optical pump—electron probe experiment to study ultrafast photoemissions from a nanometer-sized plasmonic antenna12–*** probe the real space motion of the photoemitted electrons with a 20-nm spatial resolution and a 25-fs time resolution and reveal the deflection of probe electrons by residual holes in the *** is a step toward time-resolved microscopy of electronic motion in nanostructures.

关键词： projection separation sized