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Solid-state NMR for metal-containing zeolites: From active sites to reaction mechanism

Xingling Zhao, Jun Xu, Feng Deng

《化学科学与工程前沿（英文）》 2020年 第14卷 第2期   页码 159-187 doi: 10.1007/s11705-019-1885-1

摘要： Metal-containing zeolite catalysts have found a wide range of applications in heterogeneous catalysis. To understand the nature of metal active sites and the reaction mechanism over such catalysts is of great importance for the establishment of structure-activity relationship. The advanced solid-state NMR (SSNMR) spectroscopy is robust in the study of zeolites and zeolite-catalyzed reactions. In this review, we summarize recent developments and applications of SSNMR for exploring the structure and property of active sites in metal-containing zeolites. Moreover, detailed information on host-guest interactions in the relevant zeolite catalysis obtained by SSNMR is also discussed. Finally, we highlight the mechanistic understanding of catalytic reactions on metal-containing zeolites based on the observation of key surface species and active intermediates.

关键词： metal-containing zeolites     solid-state NMR     active site     host-guest interaction     reaction mechanism    

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noble metal nanoparticle size on C–N bond cleavage performance in hydrodenitrogenation: a study of active

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 1986-2000 doi: 10.1007/s11705-023-2337-5

摘要： Breakage of the C–N bond is a structure sensitive process, and the catalyst size significantly affects its activity. On the active metal nanoparticle scale, the role of catalyst size in C–N bond cleavage has not been clearly elucidated. So, Ru catalysts with variable nanoparticle sizes were obtained by modulating the reduction temperature, and the catalytic activity was evaluated using 1,2,3,4-tetrahydroquinoline and o-propylaniline with different C–N bond hybridization patterns as reactants. Results showed a 13 times higher reaction rate for sp3-hybridized C–N bond cleavage than sp2-hybridized C–N bond cleavage, while the reaction rate tended to increase first and then decrease as the catalyst nanoparticle size increased. Different concentrations of terrace, step, and corner sites were found in different sizes of Ru nanoparticles. The relationship between catalytic site variation and C–N bond cleavage activity was further investigated by calculating the turnover frequency values for each site. This analysis indicates that the variation of different sites on the catalyst is the intrinsic factor of the size dependence of C–N bond cleavage activity, and the step atoms are the active sites for the C–N bond cleavage. When Ru nanoparticles are smaller than 1.9 nm, they have a strong adsorption effect on the reactants, which will affect the catalytic performance of the Ru catalyst. Furthermore, these findings were also confirmed on other metallic Pd/Pt catalysts. The role of step sites in C–N bond cleavage was proposed using the density function theory calculations. The reactants have stronger adsorption energies on the step atoms, and step atoms have d-band center nearer to the Fermi level. In this case, the interaction with the reactant is stronger, which is beneficial for activating the C–N bond of the reactant.

关键词： sp3/sp2-hybridized C–N bond     noble metal nanoparticle     catalytic active site     turnover frequency     DFT    

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Influence of site conditions on seismic design parameters for foundations as determined via nonlinearsite response analysis

Muhammad Tariq A. CHAUDHARY

《结构与土木工程前沿（英文）》 2021年 第15卷 第1期   页码 275-303 doi: 10.1007/s11709-021-0685-0

摘要： Site conditions, including geotechnical properties and the geological setting, influence the near-surface response of strata subjected to seismic excitation. The geotechnical parameters required for the design of foundations include mass density ( ), damping ratio ( ), shear wave velocity ( ), and soil shear modulus ( ). The values of the last three parameters are sensitive to the level of nonlinear strain induced in the strata due to seismic ground motion. In this study, the effect of variations in soil properties, such as plasticity index ( ), effective stress ( ), over consolidation ratio (OCR), impedance contrast ratio ( ) between the bedrock and the overlying strata, and depth of soil strata over bedrock ( ), on seismic design parameters ( , , and ) was investigated for National Earthquake Hazards Reduction Program (NEHRP) site classes C and D, through 1D nonlinear seismic site response analysis. The Morris one-at-a-time (OAT) sensitivity analysis indicated that , , and were significantly influenced by variations in , while affected more than it affected and . However, the influence of on these parameters was less significant. It was also found that variations in soil properties influenced seismic design parameters in soil type D more significantly than in soil type C. Predictive relationships for , , and were derived based on the 1D seismic site response analysis and sensitivity analysis results. The , , and values obtained from the analysis were compared with the corresponding values in NEHRP to determine the similarities and differences between the two sets of values. The need to incorporate and in the metrics for determining , , and for the seismic design of foundations was highlighted.

关键词： site effects     1D seismic site response analysis     sensitivity analysis     foundations     shear wave velocity     soil shear modulus    

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Development and application of an off-site maintenance system in the petrochemical industry

Ruisheng YONG, Yanbing YE, Hanbin LUO, Lieyun DING

《工程管理前沿（英文）》 2017年 第4卷 第2期   页码 111-126 doi: 10.15302/J-FEM-2017027

摘要： On-site maintenance (ONSM) is critical to ensuring the safety of equipment in the petrochemical industry. However, many accidents occur during ONSM processes because of unstable equipment, complicated work environment, and human error. To reduce congestion and exposure to hazards during on-site operations and thereby reduce the probability of accidents, off-site maintenance (OFSM) is proposed based on Energy Release Theory (ERT). The information requirements for OFSM are analyzed. A support system for OFSM, which makes use of visualization, information management, and localization capabilities, is developed. A case study utilizing OFSM and its support system for an oil-loading facility of a petrochemical company is conducted. The application results indicated that implementation of OFSM system can significantly reduce the operation risks and can improve the operation efficiency.

关键词： on-site maintenance     petrochemical industry     safety     off-site maintenance system    

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雅砻江普斯罗坝址深部裂缝带成因的探讨

李玶,李愿军,杨美娥,赵东芝

《中国工程科学》 2007年 第9卷 第3期   页码 11-20

摘要：

雅砻江普斯罗坝址在工程勘探过程中，发现了深部裂缝带，裂缝带位于１００～２００m深处，与地表有 巨厚的完整岩体相隔，产状与该区的一组NE向断裂基本一致；断层物质的最新形成年龄为２畅７～９万年，裂缝 面上有水平、斜向和上下擦痕，表明深部裂缝带可能是断裂带新活动的结果。断裂新活动所产生的地震波，受 到疏松破碎带的阻挡，导致深部裂缝带出现。这一成因机制，在地下核爆炸和岩石动力学的试验观测中有所证实。

关键词： 雅砻江普斯罗坝址     深部裂缝带     卸荷和重力滑塌     活断层    

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An integrated approach to site-specific management zone delineation

Yuxin MIAO, David J. MULLA, Pierre C. ROBERT

《农业科学与工程前沿（英文）》 2018年 第5卷 第4期   页码 432-441 doi: 10.15302/J-FASE-2018230

摘要：

Dividing fields into a few relatively homogeneous management zones (MZ) is a practical and cost-effective approach to precision agriculture. There are three basic approaches to MZ delineation using soil and/or landscape properties, yield information, and both sources of information. The objective of this study is to propose an integrated approach to delineating site-specific MZ using relative elevation, organic matter, slope, electrical conductivity, yield spatial trend map, and yield temporal stability map (ROSE-YSTTS) and evaluate it against two other approaches using only soil and landscape information (ROSE) or clustering multiple year yield maps (CMYYM). The study was carried out on two no-till corn-soybean rotation fields in eastern Illinois, USA. Two years of nitrogen (N) rate experiments were conducted in Field B to evaluate the delineated MZs for site-specific N management. It was found that in general the ROSE approach was least effective in accounting for crop yield variability (8.0%–9.8%), while the CMYYM approach was least effective in accounting for soil and landscape (8.9%–38.1%), and soil nutrient and pH variability (9.4%–14.5%). The integrated ROSE-YSTTS approach was reasonably effective in accounting for the three sources of variability (38.6%–48.9%, 16.1%–17.3% and 13.2%–18.7% for soil and landscape, nutrient and pH, and yield variability, respectively), being either the best or second best approach. It was also found that the ROSE-YSTTS approach was effective in defining zones with high, medium and low economically optimum N rates. It is concluded that the integrated ROSE-YSTTS approach combining soil, landscape and yield spatial-temporal variability information can overcome the weaknesses of approaches using only soil, landscape or yield information, and is more robust for MZ delineation. It also has the potential for site-specific N management for improved economic returns. More studies are needed to further evaluate their appropriateness for precision N and crop management.

关键词： economically optimum nitrogen rate     fuzzy cluster analysis     precision nitrogen management     site-specific management     soil landscape property     yield map    

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Site-directed mutagenesis of long QT syndrome KCNQ1 gene

LI Wei, WANG Bin, XU Qiumei, KE Qinmei, YANG Junguo, DU Rong, TIAN Li, WANG Qing

《医学前沿（英文）》 2008年 第2卷 第1期   页码 100-104 doi: 10.1007/s11684-008-0018-x

摘要： To construct a polymerase chain reaction (PCR) site-directed mutagenesis of the long QT syndrome KCNQ1 gene , two sets of primers were designed according to the sequence of KCNQ1 cDNA and a mismatch was introduced into primers. Mutagenesis was performed in a two-step PCR. The amplified fragments from the third PCR which contained the mutation site were sub-cloned into the T-vector pCR2.1. Then, the fragments containing the mutation site was obtained from pCR2.1 using restriction enzymes digestion and inserted into the same restriction site of pIRES-EGFP-KCNQ1. The sequencing analysis shows that the mutation site was correct. Mutation from A to G in site 983 of KCNQ1 cDNA was found. Using the Effectene transfection reagent, pIRES-EGFP-KCNQ1 (G983A) was transfected into HEK cells successfully. These results may shed light on further functional study of KCNQ1 gene.

关键词： restriction     digestion     syndrome     sequence     site-directed mutagenesis    

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Construction Technology of Off-Site Precast Concrete Buildings

Ting Gong,Jian Yang,Hao Hu,Feng Xu

《工程管理前沿（英文）》 2015年 第2卷 第2期   页码 122-124 doi: 10.15302/J-FEM-2015039

摘要： The industrialization of building construction is gradually becoming a new choice of construction technology driven by some great advantages such as high efficiency in construction, low energy consumption and environmental friendliness. Construction management plays an important part to ensure the quality of projects. A comparison between traditional on-site and modern off-site construction methods has been conducted. The streamlining of the process including the fabrication, transportation, stacking and assembling of precast components has also been analyzed with a discussion on the BIM application in the process.

关键词： off-site construction     precast concrete     modular construction     construction management     building information model (BIM)    

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Evaluation of site response characteristic using nonlinear method (Case study: Babol, Iran)

Asskar Janalizadeh CHOOBBASTI, Sadegh REZAEI, Farzad FARROKHZAD, Pedram Haidarzaeh AZAR

《结构与土木工程前沿（英文）》 2014年 第8卷 第1期   页码 69-82 doi: 10.1007/s11709-014-0231-4

摘要： In this the present study, an attempt has been made to evaluate the seismic hazard considering local site effects by carrying out detailed geotechnical site characterization in Babol, Iran. Use of geotechnical data and synthesis of drilling data extracted from the Babol’s subsurface database have enabled authors to determine the geotechnical properties of each site. These data are consisted of twenty five boreholes up to depth of 40 m. Based on the obtained data from geotechnical investigation the study area is divided to five zones. Dynamic analysis was performed in time domain, using fully nonlinear model by PLAXIS. A series of analysis in the study area showed the site period, ranging from 0.4 to 0.8 s. Finally the obtained response spectra from fully nonlinear method were compared with site response spectra of Iran’s 2800 (earthquake) code.

关键词： fully nonlinear method     site effect     dynamic analysis     response spectra    

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Performance evaluation on the pollution control against wet weather overflow based on on-site coagulation

Zongqun Chen, Wei Jin, Hailong Yin, Mengqi Han, Zuxin Xu

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1400-z

摘要： Abstract • A way for overflow control based on on-site coagulation/flocculation was proposed. • Coagulant and flocculant dose were optimized based on pollutant removal performance. • Settling time of 5 min is enough in a proper transmission distance. • Fast removal of particulate pollutants could be achieved under varied flow. The pollution caused by wet weather overflow in urban drainage systems is a main factor causing blackening an odorization of urban rivers. The conventional overflow treatment based on coagulation/flocculation in terminal drainage systems requires relatively large space and long retention time demand that makes it not applicable in crowded urban drainage systems or under heavy rains. On-site coagulation/flocculation in terminal drainage pipes was proposed in this study which was aimed to transfer the coagulation/flocculation process to the inside of pipes at the terminal drainage system to save space and reduce the retention time of the coagulation/flocculation process. The optimized dose of chemicals was studied first which was 80 mg/L of coagulant and 0.8 mg/L of flocculant. Settling for only 5 min can remove most of the pollutants at 406.5 m of transmission distance. In addition, the relation of wet weather overflow rate and concentration of pollution load on the on-site coagulation/flocculation process was investigated, which indicated that high removal of pollutant was gained at a large range of flow velocity and pollutant concentration. Finally, the study confirmed electric neutralization, bridging, and net capture as the major mechanisms in this process, and further optimization was proposed. The proposed process can reduce much turbidity, chemical oxygen demand, and total phosphorous, but hardly remove soluble ammonia and organics. This work provides scientific guidance to address wet weather overflow in terminal drainage pipes.

关键词： Wet weather overflow     On-site coagulation/flocculation     Fast removal of particulate pollutants    

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advanced engineering measures on displacement and stress field of surrounding rock in tunnels crossing active

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0966-x

摘要： Based on significant improvements in engineering materials, three advanced engineering measures have been proposed—super anchor cables, high-strength concrete anti-fault caverns, and grouting modification using high-strength concrete-to resist fault dislocation in the surrounding rock near tunnels crossing active strike-slip faults. Moreover, single- or multiple-joint advanced engineering measures form the local rock mass-anti-fault (LRAF) method. A numerical method was used to investigate the influence of LRAF methods on the stress and displacement fields of the surrounding rock, and the anti-fault effect was evaluated. Finally, the mechanism of action of the anchor cable was verified using a three-dimensional numerical model. The numerical results indicated that the anchor cable and grouting modification reduced the displacement gradient of the local surrounding rock near the tunnels crossing fault. Furthermore, anchor cable and grouting modifications changed the stress field of the rock mass in the modified area. The tensile stress field of the rock mass in the modified anchor cable area was converted into a compressive stress field. The stress field in the modified grouting area changed from shear stress in the fault slip direction to tensile stress in the axial tunnel direction. The anti-fault cavern resisted the dislocation displacement and reduced the maximum dislocation magnitude, displacement gradient, and shear stress. Among the three advanced engineering measures, the anchor cable was the core of the three advanced engineering measures. An anchor cable, combined with other LRAF measures, can form an artificial safety island at the cross-fault position of the rock mass to protect the tunnel. The research results provide a new supporting idea for the surrounding rock of tunnels crossing active strike-slip faults.

关键词： anti-fault effect     engineering measures     LRAF method     stress and displacement field     tunnel-crossing active faults    

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Application of StrucGP in medical immunology: site-specific -glycoproteomic analysis of macrophages

《医学前沿（英文）》 2023年 第17卷 第2期   页码 304-316 doi: 10.1007/s11684-022-0964-8

摘要： The structure of N-glycans on specific proteins can regulate innate and adaptive immunity via sensing environmental signals. Meanwhile, the structural diversity of N-glycans poses analytical challenges that limit the exploration of specific glycosylation functions. In this work, we used THP-1-derived macrophages as examples to show the vast potential of a N-glycan structural interpretation tool StrucGP in N-glycoproteomic analysis. The intact glycopeptides of macrophages were enriched and analyzed using mass spectrometry (MS)-based glycoproteomic approaches, followed by the large-scale mapping of site-specific glycan structures via StrucGP. Results revealed that bisected GlcNAc, core fucosylated, and sialylated glycans (e.g., HexNAc4Hex5Fuc1Neu5Ac1, N4H5F1S1) were increased in M1 and M2 macrophages, especially in the latter. The findings indicated that these structures may be closely related to macrophage polarization. In addition, a high level of glycosylated PD-L1 was observed in M1 macrophages, and the LacNAc moiety was detected at Asn-192 and Asn-200 of PD-L1, and Asn-200 contained Lewis epitopes. The precision structural interpretation of site-specific glycans and subsequent intervention of target glycoproteins and related glycosyltransferases are of great value for the development of new diagnostic and therapeutic approaches for different diseases.

关键词： macrophage     glycoproteome     glycopeptides     N-glycan structures     PD-L1    

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Adsorption of herring sperm DNA onto pine sawdust biochar: Thermodynamics and site energy distribution

《环境科学与工程前沿（英文）》 2022年 第16卷 第11期 doi: 10.1007/s11783-022-1579-7

摘要：

● Adsorption of environmental deoxyribonucleic acid on biochar was studied.

关键词： Environmental deoxyribonucleic acid     Antibiotic resistance genes     Biochar     Adsorption thermodynamics    

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Smart construction site in mega construction projects: A case study on island tunneling project of Hong

Hongtao ZHOU, Hongwei WANG, Wei ZENG

《工程管理前沿（英文）》 2018年 第5卷 第1期   页码 78-87 doi: 10.15302/J-FEM-2018075

摘要： The construction sites of mega construction projects (MCP) often have numerous participants with interfacing work within a highly complex system. It is critical how to realize collaborative work and information sharing among such participants. The information and communication technologies (ICTs) provides a technical guarantee for solving this problem. Existing research has been achieved the partial processes digitization of construction site, but certain problems still exist: 1)information perception of the construction site is passive. 2) common collaboration and coordination problems in the construction industry have not been addressed. The emerging trends of ICTs have resulted in the integration of various computer technologies such as CPS, BIM, big data, and cloud computing into construction process, which would changes behavioral and management mode of construction sites. These new ICTs have been applied successfully in MCP, in particular, Hong Kong-Zhuhai-Macao Bridge project. A new management mode of construction sites is inspired by these case. In this paper, a new management mode of construction site for MCP has been proposed, namely, smart construction site. The ultimate goal of smart construction site is to accomplish safe, efficient and high-quality construction. This study put forward the conceptual framework for smart construction site, and have identified three key elements of smart construction site, including information support platform, collaboration work, and intelligent construction management. A case study on Hong Kong-Zhuhai-Macao Bridge project work as an evidence to support the practicability of the proposed mode. Significant contributions of this study is to propose a new management mode for MCP in construction industry, which would enrich the body of knowledge or the construction management community. Future research should be dedicated to further explore the potential of smart construction site in MCP management.

关键词： mega construction projects     smart construction site     information perception     collaborative work     intelligent construction management     information and communication technologies    

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Rapid method for on-site determination of phenolic contaminants in water using a disposable biosensor

Yuanting LI, Dawei LI, Wei SONG, Meng LI, Jie ZOU, Yitao LONG

《环境科学与工程前沿（英文）》 2012年 第6卷 第6期   页码 831-838 doi: 10.1007/s11783-012-0393-z

摘要： A disposable biosensor was fabricated using single-walled carbon nanotubes, gold nanoparticles and tyrosinase (SWCNTs-AuNPs-Tyr) modified screen-printed electrodes. The prepared biosensor was applied to the rapid determination of phenolic contaminants within 15 minutes. The SWCNTs-AuNPs-Tyr bionanocomposite sensing layer was characterized with scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry methods. The characterization results revealed that SWCNTs could lead to a high loading of tyrosinase (Tyr) with the large surface area and the porous morphology, while AuNPs could retain the bioactivity of Tyr and enhance the sensitivity. The detection conditions, including working potential, pH of supporting electrolyte and the amount of Tyr were optimumed. As an example, the biosensor for catechol determination displayed a linear range of 8.0 × 10 to 2.0 × 10 mol·L with a detection limit of 4.5 × 10 mol·L (S/ = 3). This method has a rapid response time within 10 s, and shows excellent repeatability and stability. Moreover, the resulting biosensor could be disposable, low-cost, reliable and easy to carry. This kind of new Tyr biosensor provides great potential for rapid, on-site and cost-effective analysis of phenolic contaminants in environmental water samples.

关键词： on-site determination     tyrosinase biosensor     phenolic contaminants     single-walled carbon nanotubes     gold nanoparticles     screen-printed electrodes    

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标题 作者 时间 类型 操作

Solid-state NMR for metal-containing zeolites: From active sites to reaction mechanism

Xingling Zhao, Jun Xu, Feng Deng

期刊论文

noble metal nanoparticle size on C–N bond cleavage performance in hydrodenitrogenation: a study of active

期刊论文

Influence of site conditions on seismic design parameters for foundations as determined via nonlinearsite response analysis

Muhammad Tariq A. CHAUDHARY

期刊论文

Development and application of an off-site maintenance system in the petrochemical industry

Ruisheng YONG, Yanbing YE, Hanbin LUO, Lieyun DING

期刊论文

雅砻江普斯罗坝址深部裂缝带成因的探讨

李玶,李愿军,杨美娥,赵东芝

期刊论文

An integrated approach to site-specific management zone delineation

Yuxin MIAO, David J. MULLA, Pierre C. ROBERT

期刊论文

Site-directed mutagenesis of long QT syndrome KCNQ1 gene

LI Wei, WANG Bin, XU Qiumei, KE Qinmei, YANG Junguo, DU Rong, TIAN Li, WANG Qing

期刊论文

Construction Technology of Off-Site Precast Concrete Buildings

Ting Gong,Jian Yang,Hao Hu,Feng Xu

期刊论文

Evaluation of site response characteristic using nonlinear method (Case study: Babol, Iran)

Asskar Janalizadeh CHOOBBASTI, Sadegh REZAEI, Farzad FARROKHZAD, Pedram Haidarzaeh AZAR

期刊论文

Performance evaluation on the pollution control against wet weather overflow based on on-site coagulation

Zongqun Chen, Wei Jin, Hailong Yin, Mengqi Han, Zuxin Xu

期刊论文

advanced engineering measures on displacement and stress field of surrounding rock in tunnels crossing active

期刊论文

Application of StrucGP in medical immunology: site-specific -glycoproteomic analysis of macrophages

期刊论文

Adsorption of herring sperm DNA onto pine sawdust biochar: Thermodynamics and site energy distribution

期刊论文

Smart construction site in mega construction projects: A case study on island tunneling project of Hong

Hongtao ZHOU, Hongwei WANG, Wei ZENG

期刊论文

Rapid method for on-site determination of phenolic contaminants in water using a disposable biosensor

Yuanting LI, Dawei LI, Wei SONG, Meng LI, Jie ZOU, Yitao LONG

期刊论文