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Effect of site amplifi cation on inelastic seismic response 预览
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作者 Adhikary S Singh Y 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第3期535-554,共20页
The available models for eff ective periods of site and structure are reviewed in context of frequency tuning in the inelastic seismic response of soil-structure system. The eff ect of seismic intensity and ductility ... The available models for eff ective periods of site and structure are reviewed in context of frequency tuning in the inelastic seismic response of soil-structure system. The eff ect of seismic intensity and ductility demand, on the eff ective periods, is investigated, and inelastic site amplifi cation is shown to be strongly correlated to the normalized eff ective period. Two non-dimensional parameters, analogous to the conventional site amplifi cation factors in codes, are defi ned to quantify the inelastic site amplifi cation. It is shown that the inelastic site amplifi cation factor (i.e. ratio of constant ductility spectral ordinates at soil site to those at rock outcrop) is able to represent the site eff ects more clearly, as compared to the inelastic site amplifi cation ratio (i.e. ratio of inelastic spectral ordinates at soil site to the corresponding elastic spectral ordinates at rock outcrop). Further, the peak in the amplifi cation factor corresponding to the eff ective site period diminishes rapidly with increasing ductility demand. 展开更多
关键词 SITE amplifi CATION normalized RESPONSE SPECTRA eff ective period INELASTIC SEISMIC RESPONSE INELASTIC SITE amplifi CATION factor
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Recurrent surgical site infection after anterior cruciate ligament reconstruction:A case report 预览
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作者 Don Koh Shi Ming Tan Andrew Hwee Chye Tan 《世界骨科杂志(英文版)》 2019年第6期255-261,共7页
BACKGROUND Surgical site infections following anterior cruciate ligament(ACL)reconstruction are an uncommon but potentially devastating complication.In this study,we present an unusual case of recurrent infection of t... BACKGROUND Surgical site infections following anterior cruciate ligament(ACL)reconstruction are an uncommon but potentially devastating complication.In this study,we present an unusual case of recurrent infection of the knee after an ACL reconstruction,and discuss the importance of accurate diagnosis and appropriate management,including the issue of graft preservation versus removal.CASE SUMMARY A 33-year-old gentleman underwent ACL reconstruction using a hamstring tendon autograft with suspensory Endobutton fixation to the distal femur and an interference screw fixation to the proximal tibia.Four years after ACL reconstruction,he developed an abscess over the proximal tibia and underwent incision and drainage.Remnant suture material was found at the base of the abscess and was removed.Five years later,he re-presented with a lateral distal thigh abscess that encroached the femoral tunnel.He underwent incision and drainage of the abscess which was later complicated by a chronic discharging sinus.Repeated magnetic resonance imaging revealed a fistulous communication between the lateral thigh wound extending toward the femoral tunnel with suggestion of osteomyelitis.Decision was made for a second surgery and the patient was counselled about the need for graft removal should there be intraarticular involvement.Knee arthroscopy revealed the graft to be intact with no evidence of intra-articular involvement.As such,the decision was made to retain the ACL graft.Re-debridement,excision of the sinus tract and removal of Endobutton was also performed in the same setting.Joint fluid cultures did not grow bacteria.However,tissue cultures from the femoral tunnel abscess grew Enterobacter cloacae complex,similar to what grew in tissue cultures from the tibial abscess five years earlier.In view of the recurrent and indolent nature of the infection,antibiotic therapy was escalated from Clindamycin to Ertapenem.He completed a six-week course of intravenous antibiotics and has been well for six months since surgery,with excellent 展开更多
关键词 Chronic SURGICAL SITE INFECTION Anterior CRUCIATE ligament reconstruction SURGICAL SITE INFECTION Graft preservation ENTEROBACTER CLOACAE complex Septic arthritis Case report
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Site-Specific Zonation of Seismic Site Effects by Optimization of the Expert GIS-Based Geotechnical Information System for Western Coastal Urban Areas in South Korea
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作者 Han-Saem Kim Chang-Guk Sun Hyung-Ik Cho 《国际灾害风险科学学报:英文版》 CSCD 2019年第1期117-133,共17页
Earthquake-induced disasters are often more severe over soft soils than over firm soils or rocks owing to the seismic site effects related to the amplification of ground motion. On a regional scale, such differences c... Earthquake-induced disasters are often more severe over soft soils than over firm soils or rocks owing to the seismic site effects related to the amplification of ground motion. On a regional scale, such differences can be estimated by spatially predicting the subsurface soil thickness over the entire target area. Generally, soil deposits are deeper in coastal or riverside areas than in inland regions. In this study, the seismic site effects in the coastal metropolitan areas of Incheon and Bucheon, South Korea, were assessed to provide information on seismic hazards. Spatial prediction of geotechnical layers was performed for the entire study area within an advanced GIS framework. Approximately 7500 existing borehole records in the Incheon and Bucheon areas were gathered and archived into a GIS database. Surface geotechnical data were acquired from a walk-over survey. Based on the optimized geo-data, spatial zoning maps of site-specific seismic response parameters, based on multiscale geospatial modeling, were created and presented for use in a regional seismic mitigation strategy. Seismic zonation was also performed to determine site coefficients for seismic design over the entire target area and to compare them with each other. We verified that the geotechnical data based spatial zonation would be useful for seismic hazard mitigation. 展开更多
关键词 COASTAL urban areas Geodata Geostatistical spatial ZONATION SEISMIC SITE effects SITE classification South Korea
海绵城市理念在水厂设计中的应用 预览
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作者 李秋艳 单春林 《建筑技术开发》 2019年第8期21-22,共2页
国家提倡采用海绵城市理念规划建设城市,在工矿企业设计中也应当采用海绵城市的理念:优先利用植草沟、渗水砖、雨水花园、下沉式绿地等"绿色"措施来组织排水,以"慢排缓释"和"源头分散"控制为设计理念,可... 国家提倡采用海绵城市理念规划建设城市,在工矿企业设计中也应当采用海绵城市的理念:优先利用植草沟、渗水砖、雨水花园、下沉式绿地等"绿色"措施来组织排水,以"慢排缓释"和"源头分散"控制为设计理念,可以有效的收集了雨水,并进行再利用。 展开更多
关键词 海绵城市 场地 排水
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Reducing anastomotic leak in colorectal surgery:The old dogmas and the new challenges 预览
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作者 Jeremy Meyer Surennaidoo Naiken +4 位作者 Niki Christou Emilie Liot Christian Toso Nicolas Christian Buchs Frédéric Ris 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第34期5017-5025,共9页
Anastomotic leak(AL)constitutes a significant issue in colorectal surgery,and its incidence has remained stable over the last years.The use of intra-abdominal drain or the use of mechanical bowel preparation alone hav... Anastomotic leak(AL)constitutes a significant issue in colorectal surgery,and its incidence has remained stable over the last years.The use of intra-abdominal drain or the use of mechanical bowel preparation alone have been proven to be useless in preventing AL and should be abandoned.The role or oral antibiotics preparation regimens should be clarified and compared to other routes of administration,such as the intravenous route or enema.In parallel,preoperative antibiotherapy should aim at targeting collagenase-inducing pathogens,as identified by the microbiome analysis.AL can be further reduced by fluorescence angiography,which leads to significant intraoperative changes in surgical strategies.Implementation of fluorescence angiography should be encouraged.Progress made in AL comprehension and prevention might probably allow reducing the rate of diverting stoma and conduct to a revision of its indications. 展开更多
关键词 Anastomotic LEAKAGE RECTAL SURGERY COLIC SURGERY Prevention Surgical site infection ANASTOMOSIS COMPLICATION
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以场地与建构作为起点--上海浦东东岸贯通桥设计
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作者 张佳晶 《建筑学报》 CSSCI 北大核心 2019年第8期53-59,共7页
通过对2016年上海浦江东岸23km水岸上其中5座桥的设计策略分析,阐述建筑师在桥梁设计中的思考方法,以及建筑师介入市政的重要意义。
关键词 桥梁 市政 东岸 建构(这里泛指建筑结构与构造) 场地 建筑师
基于BIM的建筑施工现场安全管理研究 预览
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作者 丁徐骏 《工程建设(重庆)》 2019年第9期74-75,共2页
应用建筑信息模型技术做建筑施工的安全管理不同于传统的项目现场安全管理工作,后者依赖工作人员的人为管理,而BIM技术更多的依靠科学的分析判断来进行建筑项目的安全管理工作的规划和实施,对项目安全形势的准确判断也大大提高。现场危... 应用建筑信息模型技术做建筑施工的安全管理不同于传统的项目现场安全管理工作,后者依赖工作人员的人为管理,而BIM技术更多的依靠科学的分析判断来进行建筑项目的安全管理工作的规划和实施,对项目安全形势的准确判断也大大提高。现场危险源分析、安全技术的披露、危险地区的隔离以及虚拟紧急演习,显著的改善了传统的项目安全管理做法,建立起了更为精确的安全管理体系。 展开更多
关键词 BIM 建筑施工 现场 安全管理
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差分像运动视宁度优化监测法 预览
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作者 王子跃 任德清 《天文研究与技术》 CSCD 2019年第1期114-122,共9页
大气视宁度是衡量台址大气光学品质的重要指标。差分像运动视宁度监测仪(Differential Image Motion Monitor,DIMM)被广泛应用于国内外天文选址的视宁度测量作业。介绍了一种优良的视宁度测量方法--差分像运动视宁度优化监测(Improved t... 大气视宁度是衡量台址大气光学品质的重要指标。差分像运动视宁度监测仪(Differential Image Motion Monitor,DIMM)被广泛应用于国内外天文选址的视宁度测量作业。介绍了一种优良的视宁度测量方法--差分像运动视宁度优化监测(Improved to Differential Image Motion Monitor,I-DIMM)法。首先对I-DIMM的结构设计和视宁度计算方法进行了详细描述;随后通过设置0.36 m和0.12 m两种口径望远镜进行视宁度的模拟测量,将I-DIMM测量结果与传统的DIMM测量的结果进行对比,均证明I-DIMM视宁度计算方法比DIMM更为精确;最后对模拟结果进行了分析,证明了I-DIMM相比于DIMM的优势。 展开更多
关键词 差分像运动视宁度优化监测法 大气视宁度 台址 差分像运动视宁度监测仪
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Hydrogen etching induced hierarchical meso/micro-pore structure with increased active density to boost ORR performance of Fe-N-C catalyst 预览
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作者 Liqin Gao Meiling Xiao +3 位作者 Zhao Jin Changpeng Liu Junjie Ge Wei Xing 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第8期17-23,I0002共8页
Rational regulation on pore structure and active site density plays critical roles in enhancing the performance of Fe-N-C catalysts. As the microporous structure of the carbon substrate is generally regarded as the ac... Rational regulation on pore structure and active site density plays critical roles in enhancing the performance of Fe-N-C catalysts. As the microporous structure of the carbon substrate is generally regarded as the active site hosts, its hostility to electron/mass transfer could lead to the incomplete fulfillment of the catalytic activity. Besides, the formation of inactive metallic Fe particles during the conventional catalyst synthesis could also decrease the active site density and complicate the identification of real active site. Herein, we developed a facial hydrogen etching methodology to yield single site Fe-N-C catalysts featured with micro/mesoporous hierarchical structure. The hydrogen concentration in pyrolysis process was designated to effectively regulate the pore structure and active site density of the resulted catalysts.The optimized sample achieves excellent ORR catalytic performance with an ultralow H2O2 yield(1%)and superb stability over 10,000 cycles. Our finding provides new thoughts for the rational design of hierarchically porous carbon-based materials and highly promising non-precious metal ORR catalysts. 展开更多
关键词 HIERARCHICAL meso/micro-pore structure HYDROGEN ETCHING Single site Fe-N-C catalysts Carbon-nitrogen-coordinated iron(FeN4) Oxygen reduction reaction
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基于场地环境的空间组织与立面分化——广西荔园饭店设计分析 预览
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作者 韦栋安 《建筑与文化》 2019年第7期51-53,共3页
如何应对场地环境,是建筑设计中一个重要的问题。文章对广西荔园饭店进行设计分析,探讨了在空间组织中回应场地环境,以此形成立面分化的逻辑,并通过具体的材料处理来实现的操作策略。
关键词 场地 空间组织 立面分化 材料与细部
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Regeneration of pitch pine(Pinus rigida)stands inhibited by fire suppression in Albany Pine Bush Preserve,New York 预览
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作者 Chang-Seok Lee George R.Robinson +1 位作者 Ingrid P.Robinson Hansol Lee 《林业研究:英文版》 CAS CSCD 2019年第1期233-242,共10页
The Pine Barrens in New York State are dominated by pitch pine(Pinus ridgida)and scrub oaks(Quercus ilicifolia and Q.prinoides).With fire suppression over the last 90 years or so,P.rigida regeneration has become spars... The Pine Barrens in New York State are dominated by pitch pine(Pinus ridgida)and scrub oaks(Quercus ilicifolia and Q.prinoides).With fire suppression over the last 90 years or so,P.rigida regeneration has become sparse,even in areas set aside to preserve this type of vegetation.We evaluated the effects of fire and an alternative disturbance(mechanical removal of vegetation)for increasing P.rigida regeneration in the Albany Pine Bush Preserve in eastern New York State.By comparing cover,diameter and height of P.rigida,Q.ilicifolia,Q.prinoides,and Vaccinium spp.(blueberry)growing on the sites with a known fire history,we documented structural and compositional changes in the vegetation since its establishment.We also compared sites on which Quercus sprouts were controlled through mechanical removal.In the years following a disturbance,height and cover of Q.ilicifolia increased continuously and the species became increasingly competitive.Both the density of P.rigida seedlings and Vaccinium cover decreased significantly as the diameter and height of Quercus increased.Our results confirmed that the dominance by P.rigida could be attributed to periodic fires at intervals of 20–25 years.We conclude that removing Q.ilicifolia can favor P.rigida dominance on the barren without fire by releasing pine seedlings from competition. 展开更多
关键词 Fire Mechanical removal PINE barren PINUS rigida QUERCUS ilicifolia QUERCUS prinoides REGENERATION Safe site
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南亚热带杉木林分蓄积量生长立地与密度效应 预览
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作者 郭光智 段爱国 张建国 《林业科学研究》 CSCD 北大核心 2019年第4期19-25,共7页
[目的]揭示南亚热带不同密度和立地条件下杉木人工林蓄积量发育规律。[方法]以广西大青山36 a生杉木密度试验林为研究对象,分析A(1 667株·hm^-2 )、B(3 333株·hm ^-2 )、C(5 000株·hm^-2 )、D(6 667株·hm ^-2 )、E(... [目的]揭示南亚热带不同密度和立地条件下杉木人工林蓄积量发育规律。[方法]以广西大青山36 a生杉木密度试验林为研究对象,分析A(1 667株·hm^-2 )、B(3 333株·hm ^-2 )、C(5 000株·hm^-2 )、D(6 667株·hm ^-2 )、E(10 000株·hm^-2 )5种初植密度杉木人工林总蓄积、活立木蓄积动态变化。[结果]初植密度与立地对林分活立木蓄积生长的影响与总蓄积一致。中幼龄阶段林分总蓄积与初植密度和立地正相关,初植密度愈高,立地指数愈大,林分蓄积生长量愈大;但15 a后中等密度林分总蓄积最大。林分蓄积连年生长高峰随密度增大而愈早;平均生长达高峰后下降,密度越大下降越早、下降趋势越明显;林分蓄积连年生长量、平均生长量大多分别在10、14 a达到高峰,林分蓄积生长率降到3%时林龄为19-25 a。[结论]随初植密度增大,立地指数对林分总蓄积的影响程度减弱。若以蓄积生长量最大为培育目标,16指数级以C密度为最适宜造林密度。南亚热带杉木林首次间伐、最后间伐、主伐时间分别为10、14、25 a;主伐林龄不宜早于19 a,且初植密度愈低主伐林龄更晚,A、B密度林分的主伐林龄可推迟到25 a。 展开更多
关键词 杉木 人工林 蓄积 立地 密度 南亚热带
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Multi-aperture seeing profiler with multiple guide stars
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作者 Feng Yang Gang Zhao De-Qing Ren 《天文和天体物理学研究:英文版》 SCIE CAS CSCD 2019年第4期53-62,共10页
The daytime atmospheric turbulence profile is crucial for the design of both optical systems and the control algorithm of a solar Multi-Conjugate Adaptive Optics(MCAO) system. The Multi-Aperture Seeing Profiler(MASP) ... The daytime atmospheric turbulence profile is crucial for the design of both optical systems and the control algorithm of a solar Multi-Conjugate Adaptive Optics(MCAO) system. The Multi-Aperture Seeing Profiler(MASP) is a portable instrument which can measure the daytime turbulence profile up to~30 km. It consists of two portable small telescopes that can deliver performance similar to a SolarDifferential Image Motion Monitor +(S-DIMM+) on a 1.0 m solar telescope. In the original design of MASP, only two guide stars are used to retrieve the turbulence profile. In this paper, we studied the usage of multiple guide stars in MASP using numerical simulation, and found that there are three main advantages.Firstly, the precision of the turbulence profile can be increased, especially at a height of about 15 km, which is important for characterizing turbulence at the tropopause. Secondly, the equivalent diameter of MASP can be increased up to 30%, which will reduce the cost and weight of the instruments. Thirdly, the vertical resolution of the turbulence profile near the ground increases with the help of multiple guide stars. 展开更多
关键词 atmospheric effects site testing methods:numerical
‘Seowon,Korean Neo-Confudan Academies’:The Witness of the Spread of Chinese Confucian Culture in East Asia 预览
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作者 Han Xingyuan Jiang Xinyi 《中外文化交流:英文版》 2019年第8期43-45,共3页
"Seowon,Korean Neo-Confucian Academies"is a World Heritage Site consisting of a selection of nine seowon.They were founded in the Joseon Dynasty(15th to 19th century A.D.).The"Korean Neo-Confucian Acade... "Seowon,Korean Neo-Confucian Academies"is a World Heritage Site consisting of a selection of nine seowon.They were founded in the Joseon Dynasty(15th to 19th century A.D.).The"Korean Neo-Confucian Academies"is the product of the exchange and mutual learning of ancient Asian civilizations,and also the embodiment of the spread and development of Confucian culture originating from China in the Asian cultural circle and integration with local culture. 展开更多
关键词 World HERITAGE Site EMBODIMENT CIVILIZATIONS
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基于山地地形的高速公路服务区建筑设计浅析 预览
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作者 刘洋 石东浩 《华中建筑》 2019年第11期41-45,共5页
21世纪以来,中国高速公路建设如火如荼,与高速公路相应配套建设的高速公路服务区同样方兴未艾。中国南方地区相比北方地区来说,山地地形分布更加广泛,对于高速公路服务区的建设造成了一定的限制。研究基于山地地形,以建成案例对高速公... 21世纪以来,中国高速公路建设如火如荼,与高速公路相应配套建设的高速公路服务区同样方兴未艾。中国南方地区相比北方地区来说,山地地形分布更加广泛,对于高速公路服务区的建设造成了一定的限制。研究基于山地地形,以建成案例对高速公路服务区建筑设计在场所制约、人群需求以及地域文化等三个方面进行分析,提出了一系列适应性设计策略。 展开更多
关键词 高速公路服务区 山地 场地 需求 文化
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Facile synthesis of ultrathin metal-organic framework nanosheets for Lewis acid catalysis
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作者 Xiaofei Zhang Lin Chang +7 位作者 Zhongjie Yang Yanan Shi Chang Long Jianyu Han Binhao Zhang Xueying Qiu Guodong Li Zhiyong Tang 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第2期437-440,共4页
Ultrathin metalorganic framework (MOF) nanosheets are attracting great interest in catalysis due to their unique and intriguing two-dime nsional (2D) features. Although many progresses have been achieved, it is still ... Ultrathin metalorganic framework (MOF) nanosheets are attracting great interest in catalysis due to their unique and intriguing two-dime nsional (2D) features. Although many progresses have been achieved, it is still highly desirable to develop novel strategies for controllable synthesis of the well-defined ultrathin MOF nanosheets. Herein we report a polyvinylpyrrolidone (PVP)-assisted route to synthesize the ultrathin Ni-MOF nanosheets characteristic of 1.5 nm in thickness, in which PVP is reacted with 2-aminoterephthalic acid (H2BDC-NH2) via formation of C=N bon d, followed by coord inatio n with Ni2+ io ns to form the ultrathi n MOF n anosheets. Impressively, when used in the Kno eve nagel condensation reactions of propane dinitrile with different aldehydes, ultrathin Ni-MOF nanosheets display the significantly enhanced catalytic activity and good stability in respect with the bulk Ni-MOF, mainly owing to the exposed active sites as well as facile mass transfer and diffusion of substrates and products. 展开更多
关键词 ULTRATHIN NANOSHEET METAL-ORGANIC framework Lewis acid site KNOEVENAGEL CONDENSATION
土壤电阻加热技术原位修复有机污染土壤的关键问题与展望
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作者 焦文涛 韩自玉 +5 位作者 吕正勇 马栋 胡健 田垚 代子俊 王静 《环境工程学报》 CAS CSCD 北大核心 2019年第9期2027-2036,共10页
为解决我国近年来重污染企业搬迁遗留的有机污染土壤问题,土壤电阻加热修复技术(electrical resistance heating,ERH)等热处置技术日益受到重视。ERH是目前修复挥发性、半挥发性有机污染土壤最具有潜力的原位热修复技术之一,其污染物去... 为解决我国近年来重污染企业搬迁遗留的有机污染土壤问题,土壤电阻加热修复技术(electrical resistance heating,ERH)等热处置技术日益受到重视。ERH是目前修复挥发性、半挥发性有机污染土壤最具有潜力的原位热修复技术之一,其污染物去除率及土壤性质变化是用以评估该土壤修复技术的核心指标。在查阅文献的基础上,系统分析了热处置及电阻加热技术相关原理与适用范围,并对ERH处置过程中土壤性质可能发生的变化进行了深入讨论,以期为我国有机污染土壤原位热修复技术的推广和应用提供参考。 展开更多
关键词 土壤修复 热脱附 电阻加热技术 原位
Monitoring biofouling based on aerobic respiration in reverse osmosis system
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作者 Youngjae Yu Keun-Young Park +5 位作者 Jaehyun Jung Wonjung Song Jaehyeok Kim Junhee Ryu Harshad Lade Jihyang Kweon 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第4期247-256,共10页
A monitoring method of biofouling in reverse osmosis(RO) system was proposed based on the fluorescent signal of resorufin, which is reduced by nicotinamide adenine dinucleotide released from viable cells during aerobi... A monitoring method of biofouling in reverse osmosis(RO) system was proposed based on the fluorescent signal of resorufin, which is reduced by nicotinamide adenine dinucleotide released from viable cells during aerobic respiration. The fluorescent signal of resorufin reduced by planktonic cells and microorganisms of biofilm showed linearity, indicating its feasibility to monitor biofouling in a RO system. For the application of the method to the lab-scale RO system, the injection concentration of resazurin and the injection flow rate were optimized. Biofilm on RO membranes continuously operated in a lab-scale RO system was estimated by resorufin fluorescence under optimized detection condition. As a result,resorufin fluorescence on RO membrane showed a significant increase in which the permeability of RO system decreased by 30.48%. Moreover, it represented the development of biofilm as much as conventional biofilm parameters such as adenosine triphosphate,extracellular polymeric substances, and biofilm thickness. The proposed method could be used as a sensitive and low-cost technology to monitor biofouling without autopsy of membranes. 展开更多
关键词 ON-SITE MONITORING BIOFILM Aerobic RESPIRATION RESAZURIN reduction mechanism Resorufin fluorescence
The plurality eff ect of topographical irregularities on site seismic response 预览
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作者 Saeed Ghaffarpour Jahromi Sama Karkhaneh 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第3期521-534,共14页
Topography can have signifi cant eff ects on seismic ground response during an earthquake because topographic irregularities cause considerable diff erences between the seismic waves emitted by the source and the wave... Topography can have signifi cant eff ects on seismic ground response during an earthquake because topographic irregularities cause considerable diff erences between the seismic waves emitted by the source and the waves reaching the ground surface. When a seismic motion happens in a topographically irregular area, seismic waves are trapped and refl ected between the topographic features. Therefore, the interaction between topographies can amplify seismic ground response. In order to reveal how interaction between topographies infl uences seismic response, several numerical fi nite element studies have been performed by using the ABAQUS program. The results show that topographic features a greater distance between the seismic source and the site would cause greater seismic motion amplifi cation and is perceptible for the hills far away from the source and the ridges. Also, site acceleration response is impacted by surrounding topography further than site velocity and displacement response. 展开更多
关键词 TOPOGRAPHY eff ECTS surrounding TOPOGRAPHY site seismic response ABAQUS PROGRAM and PLAXIS PROGRAM
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First principles study of Fenton reaction catalyzed by FeOCl:reaction mechanism and location of active site
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作者 Xuan-Xuan Ji Hai-Feng Wang Pei-Jun Hu 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第8期783-792,共10页
Fe-based solid catalysts in promoting Fenton reaction to generate ·OH radical has drawn much attention,and interestingly,FeOCl was reported to have superior activity compared with the traditional Fe2 O3 catalysts... Fe-based solid catalysts in promoting Fenton reaction to generate ·OH radical has drawn much attention,and interestingly,FeOCl was reported to have superior activity compared with the traditional Fe2 O3 catalysts.However,the mechanism of Fenton reaction on FeOCl and the origin of high activity remain unclear.Herein,by virtue of DFT+ U calculations,the H2 O2 decomposition and conversion mechanism on FeOCl(100)surface were systematically investigated.It is found that on clean FeOCl(100)surface,the exposed[Fe^3+-Fe^3+]sites can hardly break O-O bond of H2 O2 into OH groups,but instead H2 O2 tends to dehydrogenate by the surface lattice O,resulting in a series of side reactions and final conversion into O2,while the left H atoms gradually saturate the surface lattice O and reduce Fe^3+ into Fe^2+.On fully H-covered FeOCl(100),H2O2 can efficiently dissociate at[Fe^2+-Fe^2+]sites into two OH,but OH binds with Fe^2+ so strongly that it cannot desorb as OH radical as easily as that on Fe^3+.Interestingly,FeOCl(100)tends to be partially protonated in the real acid solution,which,along with H2 O2 dehydrogenation,results in the formation of active unit [Fe^2+-Fe^3+].On[Fe^2+-Fe^3+]unit,H2 O2 can easily break its O-O bond and OH at Fe3+ can desorb as OH radical,while the other OH at Fe^2+ couples with the surface H into H2O and finish the catalytic cycle.By comparison,Fe2 O3(012)cannot provide enough [Fe^2+-Fe^3+] active units due to the relative difficulty in H2 O2 dehydrogenation,which accounts for its inferior catalytic efficiency for Fenton reaction. 展开更多
关键词 FENTON reaction FeOCl Density functional theory H2O2 Active SITE
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