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Significant enhancement in catalytic ozonationefficacy: From granular to super-fine powdered activated carbon

Tianyi Chen, Wancong Gu, Gen Li, Qiuying Wang, Peng Liang, Xiaoyuan Zhang, Xia Huang

《环境科学与工程前沿（英文）》 2018年 第12卷 第1期 doi: 10.1007/s11783-018-1022-2

摘要： In this study, super-fine powdered activated carbon (SPAC) hasbeen proposed and investigated as a novel catalyst for the catalyticozonation of oxalate for the first time. SPAC was prepared from commercialgranular activated carbon (GAC) by ball milling. SPAC exhibited highexternal surface area with a far greater member of meso- and macropores(563% increase in volume). The catalytic performances of activatedcarbons (ACs) of 8 sizes were compared and the rate constant for pseudofirst-order total organic carbon removal increased from 0.012 min to 0.568 min (47-fold increase) withthe decrease in size of AC from 20 to 40 mesh (863 mm) to SPAC (~1.0 mm). Furthermore, the diffusion resistance of SPAC decreased17-fold compared with GAC. The ratio of oxalate degradation by surfacereaction increased by 57%. The rate of transformationof ozone to radicals by SPAC was 330 times that of GAC. The resultssuggest that a series of changes stimulated by ball milling, includinga larger ratio of external surface area, less diffusion resistance,significant surface reaction and potential oxidized surface all contributedto enhancing catalytic ozonation performance. This study demonstratedthat SPAC is a simple and effective catalyst for enhancing catalyticozonation efficacy.

关键词： Super-fine activated carbon     Catalytic ozonation     External surface area     Surface reaction     Hydroxyl radical    

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Genotoxicity evaluation of surface waters located in urban area of Xi’an City using

Yongjun LIU, Aining ZHANG, Xiaoyan MA, Xiaochang WANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第6期   页码 860-866 doi: 10.1007/s11783-012-0462-3

摘要： In this study, micronucleus (MCN) and chromosome aberration (CA) tests in root tip cells were carried out in order to assess the water quality and the comprehensive genotoxic potential of surface waters located in the urban area of Xi’an City, China. For these evaluations, water samples from different surface waters (four rivers, two lakes, two biological treatment plant effluents) were collected, the ultra-pure water and methyl methanesulfonate solution was used as the negative and positive control, respectively. In our results, highly significant differences in MCN permillage (average number of micronuclei per 1000 cells), CA frequencies and PI (pollution index) values were found among three rivers and two WWTP effluents, the tested samples from two rivers caused the decrease of mitotic index over 22% compared with the negative control. No significant changes were observed in micronuclei and chromosome aberrations frequencies at one river and two lakes during the period of test (wet season). These results point out a poor state of the water quality and genotoxic activity of the main surface waters in Xi’an City. It is recommended to establish a monitoring program for the presence of genotoxic agents in these surface waters.

关键词： genotoxicity     surface water     evaluation     Vicia faba    

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Upgrade of three municipal wastewater treatment lagoons using a high surface area media

John WANG, Peng JIN, Paul L. BISHOP, Fuzhi LI

《环境科学与工程前沿（英文）》 2012年 第6卷 第2期   页码 288-293 doi: 10.1007/s11783-011-0280-z

摘要： Lagoon-based municipal wastewater treatment plants (WWTPs) are facing difficulties meeting the needs of rapid population growth as well as the more stringent requirements of discharge permits. Three municipal WWTPs were modified using a high surface area media with upgraded fine-bubble aeration systems. Performance data collected showed very promising results in terms of five-day biochemical oxygen demand (BOD ), ammonia (NH ) and total suspended solids (TSS) removal. Two-year average ammonia effluents were 4.1 mg·L for Columbia WWTP, 4 mg·L for Larchmont WWTP and 2.1 mg·L for Laurelville WWTP, respectively. Two- year average BOD effluents were 6.8, 4.9 and 2.7 mg·L , and TSS effluents were 15.0, 9.6 and 7.5 mg·L . The systems also showed low fecal coliform (FC) levels in their effluents.

关键词： wastewater lagoons     wastewater biological treatment     ammonia removal     high surface area media     fine bubble aeration    

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Perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFASs) in surface and tap water around

Yong QIU, He JING, Hanchang SHI,

《环境科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 301-310 doi: 10.1007/s11783-010-0236-8

摘要： Perfluorinated compounds (PFCs) are ubiquitously distributed in the environment mainly as perfluoro-carboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFASs). In this paper, six PFCAs and two PFASs were quantified in surface and tap water samples from 12 sites around Lake Taihu near Shanghai City in East China. Predominant PFCs were perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), of which the concentration ranges were 6.8–206 and 1.2–45 ng·L, the geometric means were 35.3 and 9.4 ng·L, and the median (quartile range) values were 31.4 (34.4) and 10.4 (10.7) ng·L, respectively. Other PFCs were also detected but in much lower concentrations than PFOA. The sources of the PFCs were expected to be direct industrial discharges in the Lake Taihu area, and this area was also a possible source of PFCs contaminations in Shanghai district in the downstream. PFCs distributions were found different in the upstream, downstream and north part of Lake Taihu. Occurrences of PFCs in the tap water in Lake Taihu area indicated their exposure to the local people. A brief estimation of the environmental risks by PFCs implied no acute or immediate risks from PFCs to local human health, but chronic risks from PFOA in the tap water should be considered in the downstream regions.

关键词： surface and tap water     perfluorocarboxylic acids (PFCAs)     perfluoroalkyl sulfonates (PFASs)     Lake Taihu area     ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS)    

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Prediction on CO

Kaiwen HUANG, Ao LI, Bing XIA, Tao DING

《结构与土木工程前沿（英文）》 2020年 第14卷 第3期   页码 746-759 doi: 10.1007/s11709-020-0635-2

摘要： Carbonation of concrete is a process which absorbs carbon dioxide (CO ). Recycled aggregate concrete (RAC) may own greater potential in CO uptake due to the faster carbonation rate than natural aggregate concrete (NAC). A quantitative model was employed to predict the CO uptake of RAC in this study. The carbonation of RAC and the specific surface area of recycled coarse aggregates (RCAs) were tested to verify accuracy of the quantitative model. Based on the verified model, results show that the CO uptake capacity increases with the increase of RCA replacement percentage. The CO uptake amount of 1 m C30 RAC within 50 years is 10.6, 13.8, 17.2, and 22.4 kg when the RCA replacement percentage is 30%, 50%, 70%, and 100%, respectively. The CO uptake by RCAs is remarkable and reaches 35.8%–64.3% of the total CO uptake by RAC when the RCA storage time being 30 days. Considering the fact that the amount of old hardened cement paste in RCAs is limited, there is an upper limit for the CO uptake of RCAs.

关键词： RAC     CO2 uptake     carbonation     specific surface area     RCA    

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nitride enabled benzimidazoles production from furyl/aryl bio-alcohols and -nitroanilines without an external

《化学科学与工程前沿（英文）》 2023年 第17卷 第1期   页码 68-81 doi: 10.1007/s11705-022-2174-y

摘要： Benzimidazole derivatives have wide-spectrum biological activities and pharmacological effects, but remain challenging to be produced from biomass feedstocks. Here, we report a green hydrogen transfer strategy for the efficient one-pot production of benzimidazoles from a wide range of bio-alcohols and o-nitroanilines enabled by cobalt nitride species on hierarchically porous and recyclable nitrogen-doped carbon catalysts (Co/CNx-T, T denotes the pyrolysis temperature) without using an external hydrogen source and base additive. Among the tested catalysts, Co/CNx-700 exhibited superior catalytic performance, furnishing 2-substituted benzimidazoles in 65%–92% yields. Detailed mechanistic studies manifest that the coordination between Co2+ and N with appropriate electronic state on the porous nitrogen-doped carbon having structural defects, as well as the remarkable synergetic effect of Co/N dual sites contribute to the pronounced activity of Co/CNx-700, while too high pyrolysis temperature may cause the breakage of the catalyst Co–N bond to lower down its activity. Also, it is revealed that the initial dehydrogenation of bio-alcohol and the subsequent cyclodehydrogenation are closely correlated with the hydrogenation of nitro groups. The catalytic hydrogen transfer-coupling protocol opens a new avenue for the synthesis of N-heterocyclic compounds from biomass.

关键词： biomass conversion     furanic compounds     benzimidazoles     hydrogen transfer     bifunctional catalysis    

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Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain

CHEN Changfu, XIAO Shujun, YANG Yu

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 329-333 doi: 10.1007/s11709-007-0043-x

摘要： Based on the unified strength theory [1], a unified strength criterion for strain softening materials, such as concrete or rock, was derived, and the elastic and plastic limit loads of a thick-walled cylinder made of these materials subject to external pressure were also given. In addition, the influence of some factors on the limit loads of such cylinders as the ratio of the external radius to internal radius,/, the coefficient , which reflects the effect of medium principal stress and the normal stress of the relevant surface on the material destroy degree, the ratio of tensile strength to compressed strength of the material, , and the damage variable
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monitoring of the strengthening construction of a segmental box girder bridge and field testing of external

Ali Fadhil NASER, Zonglin WANG

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 308-320 doi: 10.1007/s11709-012-0140-3

摘要： Prestressed concrete segmental box girder bridges are composed of short concrete segments that are either precast or cast in situ and then joined together by longitudinally post-tensioning internal, external, or mixed tendons. The objectives of this study are to monitor the construction process of the external prestressing tendons to strengthen the bridge structure and perform a field load test to measure the strain and the deflection of the anchorage devices of the external prestressing tendons to determine the state of these devices after tension forces are applied. The monitoring process of the external prestressing tendons construction includes inspecting the cracks in the diaphragm anchorage and the deviation block devices before the tension forces are applied to the external tendons; measuring the deformation of the steel deviation cross beam during the tension process; measuring the deformation of the box girder after different levels of tension forces are applied; measuring the elongation of the external tendons in each level of the tension; and measuring the natural frequency of the external tendons after the tension process is complete. The results of the monitoring process show that the measured values of the deformation, the elongation, and the natural frequency meet the requirements. Therefore, there is no damage during the construction and the tensioning of the external prestressing tendons. A field load test is performed to the anchorage beam, the steel deviation block devices, and the steel deviation cross beam. The field load test results of the anchorage devices show that the values of the strains, the stresses, and the deflection are less than the respective allowable limit values in the requirements. Therefore, the anchorage devices have sufficient strength, and the working state is good after the tension forces are applied to the external prestressing tendons.

关键词： prestressed concrete     box girder     monitoring     external tendons     strain     deflection    

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Shear behavior of ultra-high-performance concrete beams prestressed with external carbon fiber-reinforced

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1426-1440 doi: 10.1007/s11709-021-0783-z

摘要： The ultra-high-performance concrete (UHPC) and fiber-reinforced polymer (FRP) are well-accepted high-performance materials in the field of civil engineering. The combination of these advanced materials could contribute to improvement of structural performance and corrosion resistance. Unfortunately, only limited studies are available for shear behavior of UHPC beams reinforced with FRP bars, and few suggestions exist for prediction methods for shear capacity. This paper presents an experimental investigation on the shear behavior of UHPC beams reinforced with glass FRP (GFRP) and prestressed with external carbon FRP (CFRP) tendons. The failure mode of all specimens with various shear span to depth ratios from 1.7 to 4.5 was diagonal tension failure. The shear span to depth ratio had a significant influence on the shear capacity, and the effective prestressing stress affected the crack propagation. The experimental results were then applied to evaluate the equations given in different codes/recommendations for FRP-reinforced concrete structures or UHPC structures. The comparison results indicate that NF P 18-710 and JSCE CES82 could appropriately estimate shear capacity of the slender specimens with a shear span to depth ratio of 4.5. Further, a new shear design equation was proposed to take into account the effect of the shear span to depth ratio and the steel fiber content on shear capacity.

关键词： beam     external prestressing     ultra-high-performance concrete     fiber-reinforced polymers     shear behavior     design equation    

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The effect of SiO

Ismael FLORES-VIVIAN, Rani G.K PRADOTO, Mohamadreza MOINI, Marina KOZHUKHOVA, Vadim POTAPOV, Konstantin SOBOLEV

《结构与土木工程前沿（英文）》 2017年 第11卷 第4期   页码 436-445 doi: 10.1007/s11709-017-0438-2

摘要： The nanoparticles of SiO were used in cement systems to modify the rheological behavior, to enhance the reactivity of supplementary cementitious materials, and also to improve the strength and durability. In this research, low-cost nano-SiO particles from natural hydrothermal solutions obtained by membrane ultrafiltration and, optionally, by cryochemical vacuum sublimation drying, were evaluated in portland cement based systems. ??The SiO -rich solutions were obtained from the wells of Mutnovsky geothermal power station (Far East of Russia). The constant nano-SiO dosage of 0.25% (as a solid material by weight of cementitious materials) was used to compare the cement systems with different nanoparticles against a reference mortar and a commercially available nano-SiO . Nanoparticles were characterized by X-Ray Diffraction (XRD), BET Surface Area, Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR) spectroscopy techniques. It was demonstrated that the addition of polycarboxylate ether superplasticizer and the dispersion treatment using an ultrasound processor can be used to facilitate the distribution of nano-SiO particles in the mixing water. The effect of nano-SiO particles in portland cement mortars was investigated by evaluating the flow, heat of hydration and compressive strength development. It was demonstrated that the use of nano-SiO particles can reduce the segregation and improve strength properties.

关键词： ultrafiltration     cryochemical vacuum sublimation drying     nanoparticles     portland cement     heat of hydration     surface area     compressive strength    

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Ductile extension of 3-D external circumferential cracks in pipe structures

Wuchao YANG, Xudong QIAN

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 294-303 doi: 10.1007/s11709-011-0115-9

摘要： This study investigates the ductile fracture resistance of 3-D external circumferential cracks in the wall of a steel pipe under remote tension, using a damage-mechanism model originally proposed by Gurson and Tvergaard. The ductile crack extension utilizes an element extinction technique implemented in the computational cell framework. The key parameter for the computational cell method, i.e., the initial porosity ratio , is calibrated using both the fracture resistance and the load-deformation responses obtained from fracture tests of multiple single-edge bend [SE(B)] specimens made of high-strength steel, HY80, which has a yield strength of 630 MPa. The fracture resistance along the 3-D semi-elliptical crack front is computed from the calibrated cell model. Based on the similarity concept in the near-tip stress-strain fields, this study demonstrates that an equivalent 2-D axi-symmetric model provides conservative estimations of the fracture resistance for 3-D circumferential cracks in pipes.

关键词： ductile fracture     computational cell method     G-T model     J-R curve    

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Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

《机械工程前沿（英文）》 2022年 第17卷 第1期   页码 9-9 doi: 10.1007/s11465-021-0665-z

摘要： Gear wear is one of the most common gear failures, which changes the mesh relationship of normal gear. A new mesh relationship caused by gear wear affects meshing excitations, such as mesh stiffness and transmission error, and further increases vibration and noise level. This paper aims to establish the model of mesh relationship and reveal the vibration characteristics of external spur gears with gear wear. A geometric model for a new mesh relationship with gear wear is proposed, which is utilized to evaluate the influence of gear wear on mesh stiffness and unloaded static transmission error (USTE). Based on the mesh stiffness and USTE considering gear wear, a gear dynamic model is established, and the vibration characteristics of gear wear are numerically studied. Comparison with the experimental results verifies the proposed dynamic model based on the new mesh relationship. The numerical and experimental results indicate that gear wear does not change the structure of the spectrum, but it alters the amplitude of the meshing frequencies and their sidebands. Several condition indicators, such as root-mean-square, kurtosis, and first-order meshing frequency amplitude, can be regarded as important bases for judging gear wear state.

关键词： gear wear     mesh relationship     mesh stiffness     transmission error     vibration characteristics    

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单向离合器外环应力计算的有限元方法研究

罗一新,吴波

《中国工程科学》 2004年 第6卷 第9期   页码 56-59

摘要：

单向离合器是一种常见的机械传动部件，其外环应力计算尚无理想的方法。文章以五滚柱式单向离合器为研究对象，根据外环的特点，采用有限元分析方法，分析了影响其计算精度的各种因素，计算出其外环的应力，并且将计算结果与曲梁计算法进行了比较。研究表明，有限元分析方法对于外环类零件的应力计算确是一种理想的方法。

关键词： 离合器     外环     应力     有限元    

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patients with advanced malignant obstructive jaundice treated by percutaneous transhepatic biliary external

ZHU Lidong, CHEN Xiaoping

《医学前沿（英文）》 2007年 第1卷 第4期   页码 364-368 doi: 10.1007/s11684-007-0070-y

摘要： The aim of this article was to study the influence of immunity function of advanced malignant obstructive jaundice (MOJ) treated by percutaneous transhepatic biliary external and internal drainage. Ninety-six cases of MOJ were divided into two groups according to the different ways of biliary drainage. Fifty-two external drainage tubes were placed in 41 cases of percutaneous transhepatic biliary external drainage group and 66 metal stents were placed in 55 cases of percutaneous transhepatic biliary internal drainage group. Liver function, serum TNF- and cellular function were examined one day before operation and one week after operation and liver function was re-examined two weeks after operation, in order to observe the change and analyze the asso ciation among them and compare with the control group. All patients conditions were improved after operation. In the percutaneous transhepatic biliary external and internal drainage groups, the total level of bilirubin decreased from (343.54±105.56) μ mol/L and (321.19±110.50) μ mol/L to (290.56±103.46) μ mol/L and (283.72±104.95) μ mol/L after operation respectively, which were significantly lower than pre-operation (<0.05), but there was no significant difference between the two groups (>0.05). Serum alanine aminotransferase (ALT) of all patients one week after operation was significantly lower than that before operation. TNF- in percutaneous transhepatic biliary external and internal groups decreased from (108.58±19.95) pg/mL, (109.98±16.24) pg/mL of pre-operation to (104.32±19.59) pg/mL, (83.92±13.43) pg/mL of post-operation respectively, there was notable improvement (<0.01) in internal drainage group after operation. Patients serum CD4, CD3 and CD4/CD8 were notably increased, but CD8 was notably decreased (<0.05). There was no difference in external drainage group (>0.05). There was a significant difference between the two groups. Serum TNF- and ALT had positive correlation. Percutaneous transhepatic biliary internal or external drainage was an effective and important method to treat MOJ. Patients immune function was weak when they suffered MOJ, but body s cellular immune function can be notably improved after internal biliary drainage.
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Intrinsic kinetics and external diffusion of catalytic steam gasification of fine coal char particles

Xuantao Wu, Jie Wang

《化学科学与工程前沿（英文）》 2019年 第13卷 第2期   页码 415-426 doi: 10.1007/s11705-018-1725-8

摘要： Catalytic steam gasification of fine coal char particles was carried out using a self-made laboratory reactor to determine the intrinsic kinetics and external diffusion under varying pressures (0.1–0.5 MPa) and superficial gas flow velocities (GFVs) of 13.8–68.8 cm?s . In order to estimate the gas release rate at a low GFV, the transported effect of effluent gas on the temporal gasification rate pattern was simulated by the Fluent computation and verified experimentally. The external mass transfer coefficients ( ) and the effectiveness factors were determined at lower GFVs, based on the intrinsic gasification rate obtained at a high GFV of 55.0 cm?s . The was found to be almost invariable in a wider carbon conversion of 0.2–0.7. The variations of at a median carbon conversion with GFV, temperature and pressure were found to follow a modified Chilton-Colburn correlation: (0.04< <0.19), where is total pressure and is atmospheric pressure. An intrinsic kinetics/external diffusion integrating model could well describe the gasification rate as a function of GFV, temperature and pressure over a whole gasification process.

关键词： coal char     catalytic steam gasification     pressure     kinetics     diffusion    

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标题 作者 时间 类型 操作

Significant enhancement in catalytic ozonationefficacy: From granular to super-fine powdered activated carbon

Tianyi Chen, Wancong Gu, Gen Li, Qiuying Wang, Peng Liang, Xiaoyuan Zhang, Xia Huang

期刊论文

Genotoxicity evaluation of surface waters located in urban area of Xi’an City using

Yongjun LIU, Aining ZHANG, Xiaoyan MA, Xiaochang WANG

期刊论文

Upgrade of three municipal wastewater treatment lagoons using a high surface area media

John WANG, Peng JIN, Paul L. BISHOP, Fuzhi LI

期刊论文

Perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFASs) in surface and tap water around

Yong QIU, He JING, Hanchang SHI,

期刊论文

Prediction on CO

Kaiwen HUANG, Ao LI, Bing XIA, Tao DING

期刊论文

nitride enabled benzimidazoles production from furyl/aryl bio-alcohols and -nitroanilines without an external

期刊论文

Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain

CHEN Changfu, XIAO Shujun, YANG Yu

期刊论文

monitoring of the strengthening construction of a segmental box girder bridge and field testing of external

Ali Fadhil NASER, Zonglin WANG

期刊论文

Shear behavior of ultra-high-performance concrete beams prestressed with external carbon fiber-reinforced

期刊论文

The effect of SiO

Ismael FLORES-VIVIAN, Rani G.K PRADOTO, Mohamadreza MOINI, Marina KOZHUKHOVA, Vadim POTAPOV, Konstantin SOBOLEV

期刊论文

Ductile extension of 3-D external circumferential cracks in pipe structures

Wuchao YANG, Xudong QIAN

期刊论文

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

期刊论文

单向离合器外环应力计算的有限元方法研究

罗一新,吴波

期刊论文

patients with advanced malignant obstructive jaundice treated by percutaneous transhepatic biliary external

ZHU Lidong, CHEN Xiaoping

期刊论文

Intrinsic kinetics and external diffusion of catalytic steam gasification of fine coal char particles

Xuantao Wu, Jie Wang

期刊论文