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Field experiment on biological contact oxidation process to treat polluted river water in the Dianchi

Lu LI, Shuguang XIE, Hui ZHANG, Donghui WEN

《环境科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 38-47 doi: 10.1007/s11783-009-0007-6

摘要: In this study two types of biological contact oxidation processes (BCOP), a step-feed (SBCOP) unit and an inter-recycle (IBCOP) unit, were designed to investigate the treatment of heavily polluted river water. The Daqing River, which is the largest pollutant contributor to the Dianchi Lake, one of the most eutrophic freshwater lakes in China, was taken for the case study. It was found that the SBCOP had higher adaptability and better performance in the reduction of COD, TN, and TP, which made it applicable for the treatment of polluted river water entering the Dianchi Lake. Nitrification rate was observed to be greatly affected by the influent temperature. During each season, the nitrification in the SBCOP was higher than that in the IBCOP. TN removal efficiency in the SBCOP was higher than that in the IBCOP during the winter and spring but poorer during the summer, possibly due to the inhibition of denitrification by higher dissolved oxygen level in the summer. Moreover, symbiotic algae-bacteria growth may be conducive to the removal of pollutants.

关键词: step-feed biological contact oxidation process (SBCOP)     inter-recycle biological contact oxidation process (IBCOP)     river water     removal efficiency     nitrogen transformation     the Dianchi Lake watershed    

Comparison and modeling of two biofilm processes applied to decentralized wastewater treatment

Guanglei QIU, Yonghui SONG, Peng YUAN, Liancheng XIANG, Jianfeng PENG, Ping ZENG,

《环境科学与工程前沿(英文)》 2009年 第3卷 第4期   页码 412-420 doi: 10.1007/s11783-009-0141-1

摘要: In order to control water pollution in the rapidly urbanizing South China area, biological contact oxidation (BCO) process and biological aerated filter (BAF) process were applied in a pilot-scale experiment for decentralized wastewater treatment. An investigation to find the optimal parameters of the two biofilm systems was conducted on hydraulic loading, organic loading, and aeration rate. The results indicated that the water reuse criteria required a maximum hydraulic and organic loading of 30.0 m/(m·d) and 4.0 kg COD/(m·d), respectively, as well as a minimum effluent DO of 4.0 mg/L. The utilization of a new media allowed BAF to perform better than BCO. The kinetic description of the COD removal process for BAF and BCO are Yang ZHANG,Zifu LI,Ibrahim B MAHMOOD. [J]. Front. Environ. Sci. Eng., 2014, 8(6): 825-834.Daijun ZHANG, Cui BAI, Ting TANG, Qing YANG. [J]. Front Envir Sci Eng Chin, 2011, 5(2): 291-297.Deming ZHAO, Jie CHENG, Michael R. HOFFMANN. [J]. Front Envir Sci Eng Chin, 2011, 5(1): 57-64.Bo WANG, Wei WAN, Jianlong WANG, . [J]. Front.Environ.Sci.Eng., 2009, 3(4): 380-386. Junxiong LIN , Lan WANG , . [J]. Front.Environ.Sci.Eng., 2009, 3(3): 320-324.Lu LI, Shuguang XIE, Hui ZHANG, Donghui WEN. [J]. Front Envir Sci Eng Chin, 2009, 3(1): 38-47.

关键词: biological contact oxidation     biological aerated filter     decentralized wastewater treatment     kinetic model    

Biological conversion pathways of sulfate reduction ammonium oxidation in anammox consortia

Zhen Bi, Deqing Wanyan, Xiang Li, Yong Huang

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-019-1217-1

摘要: The SRAO phenomena tended to occur only under certain conditions. High amount of biomass and non-anaerobic condition is requirement for SRAO. Anammox bacteria cannot oxidize ammonium with sulfate as electron acceptor. AOB and AnAOB are mainly responsible for ammonium conversion. Heterotrophic sulfate reduction mainly contributed to sulfate conversion. For over two decades, sulfate reduction with ammonium oxidation (SRAO) had been reported from laboratory experiments. SRAO was considered an autotrophic process mediated by anammox bacteria, in which ammonium as electron donor was oxidized by the electron acceptor sulfate. This process had been attributed to observed transformations of nitrogenous and sulfurous compounds in natural environments. Results obtained differed largely for the conversion mole ratios (ammonium/sulfate), and even the intermediate and final products of sulfate reduction. Thus, the hypothesis of biological conversion pathways of ammonium and sulfate in anammox consortia is implausible. In this study, continuous reactor experiments (with working volume of 3.8L) and batch tests were conducted under normal anaerobic (0.2≤DO<0.5 mg/L) / strict anaerobic (DO<0.2 mg/L) conditions with different biomass proportions to verify the SRAO phenomena and identify possible pathways behind substrate conversion. Key findings were that SRAO occurred only in cases of high amounts of inoculant biomass under normal anaerobic condition, while absent under strict anaerobic conditions for same anammox consortia. Mass balance and stoichiometry were checked based on experimental results and the thermodynamics proposed by previous studies were critically discussed. Thus anammox bacteria do not possess the ability to oxidize ammonium with sulfate as electron acceptor and the assumed SRAO could, in fact, be a combination of aerobic ammonium oxidation, anammox and heterotrophic sulfate reduction processes.

关键词: Anammox bacteria     Autotrophic     Biological conversion     Sulfate reducing ammonium oxidation (SRAO)    

Performance of a hybrid anaerobic-contact oxidation biofilm baffled reactor for the treatment of decentralized

Minmin LIU,Ying ZHAO,Beidou XI,Li’an HOU,Xunfeng XIA

《环境科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 598-606 doi: 10.1007/s11783-013-0576-2

摘要: A novel hybrid anaerobic-contact oxidation biofilm baffled reactor (HAOBR) was developed to simultaneously remove nitrogenous and carbonaceous organic pollutants from decentralized molasses wastewater in the study. The study was based on the inoculation of anaerobic granule sludge in anaerobic compartments and the installation of combination filler in aerobic compartments. The performance of reactor system was studied regarding the hydraulic retention time (HRT), microbial characteristics and the gas water ratio (GWR). When the HRT was 24h and the GWR was 20:1, total ammonia and chemical oxygen demand (COD) of the effluent were reduced by 99% and 91.8%, respectively. The reactor performed stably for treating decentralized molasses wastewater. The good performance of the reactor can be attributed to the high resistance of COD and hydraulic shock loads. In addition, the high solid retention time of contact oxidation biofilm contributed to stable performance of the reactor.

关键词: combination filler     contact oxidation biofilm     food wastewater     anaerobic baffled reactor    

ROOT EXUDATES FROM CANOLA EXHIBIT BIOLOGICAL NITRIFICATION INHIBITION AND ARE EFFECTIVE IN INHIBITINGAMMONIA OXIDATION IN SOIL

《农业科学与工程前沿(英文)》 2022年 第9卷 第2期   页码 177-186 doi: 10.15302/J-FASE-2021421

摘要:

A range of plant species produce root exudates that inhibit ammonia-oxidizing microorganisms. This biological nitrification inhibition (BNI) capacity can decrease N loss and increase N uptake from the rhizosphere. This study sought evidence for the existence and magnitude of BNI capacity in canola ( Brassica napus). Seedlings of three canola cultivars, Brachiaria humidicola(BNI positive) and wheat ( Triticum aestivum) were grown in a hydroponic system. Root exudates were collected and their inhibition of the ammonia oxidizing bacterium, Nitrosospira multiformis, was tested. Subsequent pot experiments were used to test the inhibition of native nitrifying communities in soil. Root exudates from canola significantly reduced nitrification rates of both N. multiformis cultures and native soil microbial communities. The level of nitrification inhibition across the three cultivars was similar to the well-studied high-BNI species B. humidicola. BNI capacity of canola may have implications for the N dynamics in farming systems and the N uptake efficiency of crops in rotational farming systems. By reducing nitrification rates canola crops may decrease N losses, increase plant N uptake and encourage microbial N immobilization and subsequently increase the pool of organic N that is available for mineralization during the following cereal crops.

关键词: ammonia oxidizing microorganisms / biological nitrification inhibition / farming rotations / nitrogen cycling / nitrogen use efficiency    

Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated

Daijun ZHANG, Cui BAI, Ting TANG, Qing YANG

《环境科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 291-297 doi: 10.1007/s11783-010-0270-6

摘要: Shortcut nitrification-denitrification, anaerobic ammonium oxidation (ANAMMOX), and methanogenesis have been successfully coupled in an Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system. As fed different synthetic wastewater with chemical oxygen demand (COD) of 300–1200 mg·L and of 30–120 mg·L at the outer recycle ratio of 200%, the influence of influent on ANAMMOX in the integrated system was investigated in this paper. The experimental results showed that higher COD concentration caused an increase in denitrification and methanogenesis but a decrease in ANAMMOX; however, when an influent with the low concentration of COD was used, the opposite changes could be observed. Higher influent concentration favored ANAMMOX when the COD concentration of influent was fixed. Therefore, low ratio would decrease competition for nitrite between ANAMMOX and denitrification, which was favorable for reducing the negative effect of organic COD on ANAMMOX. The good performance of the integrated system indicated that the bacterial community of denitrification, ANAMMOX, and methanogenesis could be dynamically maintained in the sludge of EGSB reactor for a certain range of influent.

关键词: Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system     the influence of influent     anaerobic ammonium oxidation (ANAMMOX)     shortcut nitrification-denitrification     methano-genesis    

Anoxic phosphorus removal in a pilot scale anaerobic-anoxic oxidation ditch process

Hongxun HOU, Shuying WANG, Yongzhen PENG, Zhiguo YUAN, Fangfang YIN, Wang GAN

《环境科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 106-111 doi: 10.1007/s11783-009-0005-8

摘要: The anaerobic-anoxic oxidation ditch (A /O OD) process is popularly used to eliminate nutrients from domestic wastewater. In order to identify the existence of denitrifying phosphorus removing bacteria (DPB), evaluate the contribution of DPB to biological nutrient removal, and enhance the denitrifying phosphorus removal in the A /O OD process, a pilot-scale A /O OD plant (375 L) was conducted. At the same time batch tests using sequence batch reactors (12 L and 4 L) were operated to reveal the significance of anoxic phosphorus removal. The results indicated that: The average removal efficiency of COD, , , and TN were 88.2%, 92.6%, 87.8%, and 73.1%, respectively, when the steady state of the pilot-scale A /O OD plant was reached during 31-73 d, demonstrating a good denitrifying phosphorus removal performance. Phosphorus uptake took place in the anoxic zone by poly-phosphorus accumulating organisms could be used as electron receptors in denitrifying phosphorus removal, and the phosphorus uptake rate with as the electron receptor was higher than that with when the initial concentration of either or was 40 mg/L.

关键词: wastewater treatment     anaerobic-anoxic (A2/O)     oxidation ditch (OD)     biological phosphorus removal     denitrifying phosphorus removal    

A comparison of the biological activities of ethyl acetate fractions from the stems and leaves of

Zhaolei WANG, Kai JIANG, Qinchao DING, Shujun LIU, Xiaobing DOU, Bin DING

《农业科学与工程前沿(英文)》 2020年 第7卷 第4期   页码 505-512 doi: 10.15302/J-FASE-2019271

摘要:

Pursh (PCP) is a popular traditional medicinal plant in China, widely used for the treatment of a variety of liver diseases. Although it has been long recognized that the main active elements of PCP are contained in ethyl acetate fraction (EAF), little is known so far in terms of the relative effectiveness of EAF derived from the stems versus leaves of this plant. In the current study, we prepared EAF by reflux extraction and sequential extraction from the stems (SEAF) and leaves (LEAF) of PCP and tested their hepatoprotective efficacies. The extract rates and flavonoid contents of LEAF were higher than those of SEAF. EAFs (>50 μg·mL ) prevented lipid accumulation in cells and protected against lipotoxicity injury when the concentration exceeded 25 μg·mL . More than 95% free radicals released by 2,2-diphenyl-1-picrylhydrazyl (DPPH) were eliminated by 25 μg·mL SEAF and 50 μg·mL LEAF, respectively. Further, EAFs (25 μg·mL ) also showed protective antioxidant effects, with the activity of LEAF being significantly higher than that of SEAF. EAFs (10 mg·mL ) also showed similar unspecific bacteriostatic activity. In comparison with SEAF, LEAF contained more flavonoids and had a higher anti-oxidation capability and for these reasons we suggest it should be better for clinical use.

关键词: antibacterial     anti-oxidation     lipid accumulation     lipotoxicity     Penthorum chinense Pursh    

Thin-liquid-film evaporation at contact line

Hao WANG, Zhenai PAN, Zhao CHEN

《能源前沿(英文)》 2009年 第3卷 第2期   页码 141-151 doi: 10.1007/s11708-009-0020-2

摘要: When a liquid wets a solid wall, the extended meniscus near the contact line may be divided into three regions: a nonevaporating region, where the liquid is adsorbed on the wall; a transition region or thin-film region, where effects of long-range molecular forces (disjoining pressure) are felt; and an intrinsic meniscus region, where capillary forces dominate. The thin liquid film, with thickness from nanometers up to micrometers, covering the transition region and part of intrinsic meniscus, is gaining interest due to its high heat transfer rates. In this paper, a review was made of the researches on thin-liquid-film evaporation. The major characteristics of thin film, thin-film modeling based on continuum theory, simulations based on molecular dynamics, and thin-film profile and temperature measurements were summarized.

关键词: meniscus     thin film     contact line     disjoining pressure     evaporation    

Modelling of dynamic contact length in rail grinding process

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 242-248 doi: 10.1007/s11465-014-0305-y

摘要:

Rails endure frequent dynamic loads from the passing trains for supporting trains and guiding wheels. The accumulated stress concentrations will cause the plastic deformation of rail towards generating corrugations, contact fatigue cracks and also other defects, resulting in more dangerous status even the derailment risks. So the rail grinding technology has been invented with rotating grinding stones pressed on the rail with defects removal. Such rail grinding works are directed by experiences rather than scientifically guidance, lacking of flexible and scientific operating methods. With grinding control unit holding the grinding stones, the rail grinding process has the characteristics not only the surface grinding but also the running railway vehicles. First of all, it’s important to analyze the contact length between the grinding stone and the rail, because the contact length is a critical parameter to measure the grinding capabilities of stones. Moreover, it’s needed to build up models of railway vehicle unit bonded with the grinding stone to represent the rail grinding car. Therefore the theoretical model for contact length is developed based on the geometrical analysis. And the calculating models are improved considering the grinding car’s dynamic behaviors during the grinding process. Eventually, results are obtained based on the models by taking both the operation parameters and the structure parameters into the calculation, which are suitable for revealing the process of rail grinding by combining the grinding mechanism and the railway vehicle systems.

关键词: rail grinding     contact length     dynamic model     Hamiltonian system     grinding stone     rail grinding car    

Machinability of ultrasonic vibration-assisted micro-grinding in biological bone using nanolubricant

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0717-z

摘要: Bone grinding is an essential and vital procedure in most surgical operations. Currently, the insufficient cooling capacity of dry grinding, poor visibility of drip irrigation surgery area, and large grinding force leading to high grinding temperature are the technical bottlenecks of micro-grinding. A new micro-grinding process called ultrasonic vibration-assisted nanoparticle jet mist cooling (U-NJMC) is innovatively proposed to solve the technical problem. It combines the advantages of ultrasonic vibration (UV) and nanoparticle jet mist cooling (NJMC). Notwithstanding, the combined effect of multi parameter collaborative of U-NJMC on cooling has not been investigated. The grinding force, friction coefficient, specific grinding energy, and grinding temperature under dry, drip irrigation, UV, minimum quantity lubrication (MQL), NJMC, and U-NJMC micro-grinding were compared and analyzed. Results showed that the minimum normal grinding force and tangential grinding force of U-NJMC micro-grinding were 1.39 and 0.32 N, which were 75.1% and 82.9% less than those in dry grinding, respectively. The minimum friction coefficient and specific grinding energy were achieved using U-NJMC. Compared with dry, drip, UV, MQL, and NJMC grinding, the friction coefficient of U-NJMC was decreased by 31.3%, 17.0%, 19.0%, 9.8%, and 12.5%, respectively, and the specific grinding energy was decreased by 83.0%, 72.7%, 77.8%, 52.3%, and 64.7%, respectively. Compared with UV or NJMC alone, the grinding temperature of U-NJMC was decreased by 33.5% and 10.0%, respectively. These results showed that U-NJMC provides a novel approach for clinical surgical micro-grinding of biological bone.

关键词: micro-grinding     biological bone     ultrasonic vibration (UV)     nanoparticle jet mist cooling (NJMC)     grinding force     grinding temperature    

Computation and investigation of mode characteristics in nonlinear system with tuned/mistuned contact

Houxin SHE, Chaofeng LI, Qiansheng TANG, Hui MA, Bangchun WEN

《机械工程前沿(英文)》 2020年 第15卷 第1期   页码 133-150 doi: 10.1007/s11465-019-0557-7

摘要: This study derived a novel computation algorithm for a mechanical system with multiple friction contact interfaces that is well-suited to the investigation of nonlinear mode characteristic of a coupling system. The procedure uses the incremental harmonic balance method to obtain the nonlinear parameters of the contact interface. Thereafter, the computed nonlinear parameters are applied to rebuild the matrices of the coupling system, which can be easily solved to calculate the nonlinear mode characteristics by standard iterative solvers. Lastly, the derived method is applied to a cycle symmetry system, which represents a shaft–disk–blade system subjected to dry friction. Moreover, this study analyzed the effects of the tuned and mistuned contact features on the nonlinear mode characteristics. Numerical results prove that the proposed method is particularly suitable for the study of nonlinear characteristics in such nonlinear systems.

关键词: coupling vibration     nonlinear mode     original algorithm     contact interface    

Transient analysis of thermoelastic contact problem of disk brakes

Ali BELHOCINE, Mostefa BOUCHETARA

《机械工程前沿(英文)》 2013年 第8卷 第2期   页码 150-159 doi: 10.1007/s11465-013-0266-6

摘要:

The main purpose of this study is to analyze the thermomechanical behavior of the dry contact between the brake disk and pads during the braking phase. The simulation strategy is based on computer code ANSYS11. The modeling of transient temperature in the disk is actually used to identify the factor of geometric design of the disk to install the ventilation system in vehicles. The thermal-structural analysis is then used with coupling to determine the deformation established and the Von Mises stresses in the disk, the contact pressure distribution in pads. The results are satisfactory compared to those found in the literature.

关键词: brake disks     heat flux     heat-transfer coefficient     Von Mises stress     contact pressure    

Experimental study and numerical simulation on compressive buckling behavior of thin steel skins in unilateral contact

Nicholas KEAGE, Christopher MAIOLO, Rebecca PIEROTTI, Xing MA

《结构与土木工程前沿(英文)》 2011年 第5卷 第3期   页码 335-343 doi: 10.1007/s11709-011-0121-y

摘要: In this paper, a practical test and finite element analysis has been undertaken to further investigate the effects of contact buckling. A test rig was designed and constructed to record vertical and transverse deflections of compressively loaded steel skin plates. The boundary conditions were modeled as fully fixed. A finite element analysis was also undertaken using the software package Strand7. Results from both analyses have been examined and compared to data established from previous studies on contact buckling. Both the finite element analysis and practical results correlate well with this data. The result of the investigation has confirmed contact buckling theories and has foreshadowed the onset of the newly observed phenomenon of secondary contact buckling.

关键词: compressive     buckling     thin steel skins     unilateral contact     rigid constraints    

非连续接触下滚圈的接触压力及疲劳寿命预测

时彧,肖友刚,雷先明

《中国工程科学》 2006年 第8卷 第7期   页码 54-57

摘要:

建立了非连续接触下筒体-滚圈接触压力的计算模型,得出了滚圈弯矩及弯曲应力计算公式。应用名义应力法和局部应力应变法,建立了滚圈疲劳寿命预测模型。通过实例分析,得出了如下结论:通过调窑,将滚圈的最大支承载荷控制在2500kN以内,能显著提高滚圈的疲劳寿命;在传统设计中,将滚圈支承角定为30°不合理;存在一个最佳滚圈支承角,此时滚圈疲劳寿命最大。

关键词: 滚圈     接触压力     支承角     疲劳寿命    

标题 作者 时间 类型 操作

Field experiment on biological contact oxidation process to treat polluted river water in the Dianchi

Lu LI, Shuguang XIE, Hui ZHANG, Donghui WEN

期刊论文

Comparison and modeling of two biofilm processes applied to decentralized wastewater treatment

Guanglei QIU, Yonghui SONG, Peng YUAN, Liancheng XIANG, Jianfeng PENG, Ping ZENG,

期刊论文

Biological conversion pathways of sulfate reduction ammonium oxidation in anammox consortia

Zhen Bi, Deqing Wanyan, Xiang Li, Yong Huang

期刊论文

Performance of a hybrid anaerobic-contact oxidation biofilm baffled reactor for the treatment of decentralized

Minmin LIU,Ying ZHAO,Beidou XI,Li’an HOU,Xunfeng XIA

期刊论文

ROOT EXUDATES FROM CANOLA EXHIBIT BIOLOGICAL NITRIFICATION INHIBITION AND ARE EFFECTIVE IN INHIBITINGAMMONIA OXIDATION IN SOIL

期刊论文

Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated

Daijun ZHANG, Cui BAI, Ting TANG, Qing YANG

期刊论文

Anoxic phosphorus removal in a pilot scale anaerobic-anoxic oxidation ditch process

Hongxun HOU, Shuying WANG, Yongzhen PENG, Zhiguo YUAN, Fangfang YIN, Wang GAN

期刊论文

A comparison of the biological activities of ethyl acetate fractions from the stems and leaves of

Zhaolei WANG, Kai JIANG, Qinchao DING, Shujun LIU, Xiaobing DOU, Bin DING

期刊论文

Thin-liquid-film evaporation at contact line

Hao WANG, Zhenai PAN, Zhao CHEN

期刊论文

Modelling of dynamic contact length in rail grinding process

null

期刊论文

Machinability of ultrasonic vibration-assisted micro-grinding in biological bone using nanolubricant

期刊论文

Computation and investigation of mode characteristics in nonlinear system with tuned/mistuned contact

Houxin SHE, Chaofeng LI, Qiansheng TANG, Hui MA, Bangchun WEN

期刊论文

Transient analysis of thermoelastic contact problem of disk brakes

Ali BELHOCINE, Mostefa BOUCHETARA

期刊论文

Experimental study and numerical simulation on compressive buckling behavior of thin steel skins in unilateral contact

Nicholas KEAGE, Christopher MAIOLO, Rebecca PIEROTTI, Xing MA

期刊论文

非连续接触下滚圈的接触压力及疲劳寿命预测

时彧,肖友刚,雷先明

期刊论文