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Occurrence and removal of

Lin WANG,Yongmei LI,Xiaoling SHANG,Jing SHEN

《环境科学与工程前沿（英文）》 2014年 第8卷 第4期   页码 519-530 doi: 10.1007/s11783-013-0610-4

摘要： Six wastewater treatment plants (WWTPs) were investigated to evaluate the occurrence and removal of -nitrosodimethylamine (NDMA), NDMA formation potential (FP) and four specific NDMA precursors, dimethylamine (DMA), trimethylamine (TMA), dimethylformamide (DMFA) and dimethylaminobenzene (DMAB). DMA and tertiary amines with DMA functional group commonly existed in municipal wastewater. Chemically enhanced primary process (CEPP) had no effect on removal of either NDMA or NDMA FP. In WWTPs with secondary treatment processes, considerable variability was observed in the removal of NDMA (19%–85%) and NDMA FP (16%–76%), moreover, there was no definite relationship between the removal of NDMA and NDMA FP. DMA was well removed in all the six surveyed WWTPs; its removal efficiency was greater than 97%. For the removal of tertiary amines, biologic treatment processes with nitrification and denitrification had better removal efficiency than conventional activated sludge process. The best removal efficiencies for TMA, DMFA and DMAB were 95%, 68% and 72%, respectively. CEPP could remove 73% of TMA, 23% of DMFA and 36% of DMAB. After UV disinfection, only 17% of NDMA was removed due to low dosage of UV was applied in WWTP. Although chlorination could reduce NDMA precursors, NDMA concentration was actually increased after chlorination.

关键词： N-nitrosodimethylamine     NDMA precursors     NDMA formation potential     biological treatment process     chemically enhanced primary process    

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Characteristics of typical dissolved black carbons and their influence on the formation of disinfection

《环境科学与工程前沿（英文）》 2022年 第16卷 第12期 doi: 10.1007/s11783-022-1585-9

摘要：

● The physicochemical and structural properties of DBC were characterized.

关键词： Dissolved black carbon (DBC)     Chlorine     Chloramine     Disinfection by-products (DBPs)     Disinfection by-products formation potential (DBPFP)    

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Unlocked disinfection by-product formation potential upon exposure of swimming pool water to additional

Alvyn P. Berg, Ting-An Fang, Hao L. Tang

《环境科学与工程前沿（英文）》 2019年 第13卷 第1期 doi: 10.1007/s11783-019-1098-3

摘要：

• Swimming pool water was studied for DBPs upon exposure to additional stimulants.

• DBP formation could be induced by residual chlorine and extended incubation.

• Urine led to a massive formation of chloroform with additional stimulants.

• Reactions between chlorine and anthropogenic organics were slow and long-lasting.

• Urine control and air ventilation should be on the priority list for pool management.

关键词： Trihalomethanes     Haloacetic acids     Chloroform     Residual chlorine     Anthropogenic organics     Swimming pool water    

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Trends of chemical speciation profiles of anthropogenic volatile organic compounds emissions in China, 2005–2020

Wei WEI, Shuxiao WANG, Jiming HAO, Shuiyuan CHENG

《环境科学与工程前沿（英文）》 2014年 第8卷 第1期   页码 27-41 doi: 10.1007/s11783-012-0461-4

摘要： This study estimates the detailed chemical profiles of China’s anthropogenic volatile organic compounds (VOCs) emissions for the period of 2005–2020. The chemical profiles of VOCs for seven activity sectors are calculated, based on which the Photochemical Ozone Creation Potential (POCP) of VOCs for these sectors is evaluated. At the national level, the VOCs species emitted in 2005 include alkanes, alkenes and alkynes, aromatic compounds, alcohols, ketones, aldehydes, esters, ethers and halocarbons, accounting for 26.4 wt.%, 29.2 wt.%, 21.3 wt.%, 4.7 wt.%, 5.4 wt.%, 1.7 wt.%, 2.1 wt.%, 0.7 wt.% and 2.2 wt.% of total emissions, respectively. And during 2005-2020, their mass proportions would respectively grow or decrease by -6.9%, -32.7%, 7.3%, 65.3%, 34.7%, -48.6%, 108.5%, 100.5%, and 55.4%. This change would bring about a 13% reduction of POCP for national VOCs emissions in the future. Thus, although the national VOCs emissions are expected to increase by 33% over the whole period, its ozone formation potential is estimated to rise only by 14%. Large discrepancies are found in VOCs speciation emissions among provinces. Compared to western provinces, the eastern provinces with a more developed economy would emit unsaturated hydrocarbons and benzene with lower mix ratios, and aromatic compounds except benzene, oxidized hydrocarbons and halocarbons with higher mix ratios. Such differences lead to lower POCP of VOCs emitted in eastern provinces, and higher POCP of VOCs emitted in western provinces. However, due to the large VOCs emissions from Chinese eastern region, the ozone formation potential of VOCs emission in eastern provinces would be much higher than those in western provinces by about 156%–235%.

关键词： volatile organic compounds (VOCs)     chemical speciation     ozone formation     Photochemical Ozone Creation Potential (POCP)     China    

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四川盆地致密砂岩气藏勘探现状与资源潜力评价

卞从胜,王红军,汪泽成,徐兆辉

《中国工程科学》 2012年 第14卷 第7期   页码 74-80

摘要：

川中地区是目前须家河组已发现的储量集中区，由于气源的不充分性导致气藏含水饱和度高，规模经济开发难度偏大。在成藏条件综合研究的基础上，评价认为须家河组下一步勘探潜力区主要分布在川中西部的金华—蓬溪地区须二和须四段，以及川西北部的剑阁—柘坝场地区须三段，这些区域气源灶发育，生气强度大，储层保持较好，且构造和裂缝发育，多口高产气井和规模储量的发现表明其成藏潜力巨大，将成为须家河组天然气勘探的重要新领域。

关键词： 大型化成藏     源内成藏     资源潜力     致密砂岩气     须家河组     四川盆地    

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Factors influencing the photodegradation of

Bingbing XU, Zhonglin CHEN, Fei QI, Jimin SHEN, Fengchang WU

《环境科学与工程前沿（英文）》 2009年 第3卷 第1期   页码 91-97 doi: 10.1007/S11783-009-0013-8

摘要： In order to provide basic data for practical application,photodegradation experiment of -nitrosodimethylamine (NDMA) in aqueous solution was carried out with a low-pressure Hg lamp. Effects of the initial concentration of NDMA, solution pH, dissolved oxygen, and the presence of humic acid on NDMA photodegradation were investigated. NDMA at various initial concentrations selected in this study was almost completely photodegraded by UV irradiation within 20 min, except that at 1.07 mmol/L, NDMA could be photodegraded almost completely in the acidic and neutral solutions, while the removal efficiency decreased remarkably in the alkaline solution. Dissolved oxygen enhanced the NDMA photodegradation, and the presence of humic acid inhibited the degradation of NDMA. Depending on the initial concentration of NDMA, NDMA photodegradation by UV obeyed the pseudo-first-order kinetics. Dimethylamine, nitrite, and nitrate were detected as the photodegradation products of NDMA. O was found to be the reactive oxygen species present in the NDMA photodegradation process by UV, based on the inhibiting experiments using tert-butanol and sodium azide.

关键词： N-nitrosodimethylamine (NDMA)     ultraviolet irradiation     degradation kinetic     dimethylamine     photodegradation product    

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中国致密油形成分布与资源潜力评价

庞正炼,邹才能,陶士振,杨智,吴松涛

《中国工程科学》 2012年 第14卷 第7期   页码 60-67

摘要：

系统分析了国外成熟致密油区的形成条件与典型特征，为研究中国致密油的形成分布与资源潜力评价提供借鉴和参考。研究表明，国外成功致密油区具有“三大形成条件”和“七项基本特征”。三大条件为：大面积分布的致密储层；广覆式分布成熟度适中的腐泥型优质生油层；连续型分布的致密储层与生油岩紧密接触的共生层系。七项基本特征为：圈闭界限不明显；非浮力聚集，水动力效应不明显，油水分布复杂；异常压力，裂缝高产，油质轻；非达西渗流为主；短距离运移为主；纳米级孔喉连通体系为主；规模开采需要水平井技术结合分段压裂技术。从两大方面入手，系统比对了中国致密油的形成条件与典型特征，结果表明中国致密油资源潜力大，具备良好勘探前景。

关键词： 中国致密油     勘探进展     形成条件     典型特征     资源潜力    

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Time-varying formation tracking for uncertain second-order nonlinearmulti-agent systems

Mao-peng RAN, Li-hua XIE, Jun-cheng LI

《信息与电子工程前沿（英文）》 2019年 第20卷 第1期   页码 76-87 doi: 10.1631/FITEE.1800557

摘要：

Our study is concerned with the time-varying formation tracking problem for second-order multi-agent systems that are subject to unknown nonlinear dynamics and external disturbance, and the states of the followers form a predefined time-varying formation while tracking the state of the leader. The total uncertainty lumps the unknown nonlinear dynamics and the external disturbance, and is regarded as an extended state of the agent. To estimate the total uncertainty, we design an extended state observer (ESO). Then we propose a novel ESO based time-varying formation tracking protocol. It is proved that, under the proposed protocol, the ESO estimation error and the time-varying formation tracking error can be made arbitrarily small. An application to the target enclosing problem for multiple unmanned aerial vehicles (UAVs) verifies the effectiveness and superiority of the proposed approach.

关键词： Multi-agent system     Time-varying formation     Formation tracking     Nonlinear dynamics     Extended state observer (ESO)    

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3D finite element prediction of chip flow, burr formation, and cutting forces in micro end-milling of

A. DAVOUDINEJAD, P. PARENTI, M. ANNONI

《机械工程前沿（英文）》 2017年 第12卷 第2期   页码 203-214 doi: 10.1007/s11465-017-0421-6

摘要：

Predictive models for machining operations have been significantly improved through numerous methods in recent decades. This study proposed a 3D finite element modeling (3D FEM) approach for the micro end-milling of Al6061-T6. Finite element (FE) simulations were performed under different cutting conditions to obtain realistic numerical predictions of chip flow, burr formation, and cutting forces. FE modeling displayed notable advantages, such as capability to easily handle any type of tool geometry and any side effect on chip formation, including thermal aspect and material property changes. The proposed 3D FE model considers the effects of mill helix angle and cutting edge radius on the chip. The prediction capability of the FE model was validated by comparing numerical model and experimental test results. Burr dimension trends were correlated with force profile shapes. However, the FE predictions overestimated the real force magnitude. This overestimation indicates that the model requires further development.

关键词： 3D finite element modeling     micro end-milling     cutting force     chip formation     burr formation    

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Factors controlling

Chengkun WANG, Xiaojian ZHANG, Chao CHEN, Jun WANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第2期   页码 151-157 doi: 10.1007/s11783-013-0482-7

摘要： The formation of cancinogenic nitrosamines, esp. -nitrosodimethylamine (NDMA) in water and wastewater treatment plants has drawn much attention in recent years. Dissolved organic matter from the transported Luan River water as water source of Tianjin was fractionated with different XAD resins and a series of ultra-filtration membranes with molecular weight (MW) cut-offs of 5k Da, 3k Da, and 1k Da, respectively. The NDMA yields from the raw water and each fraction were measured to investigate their role in NDMA yield. Results indicated that the hydrophilic fraction had a higher NDMA yield than those of hydrophobic fraction and transphilic fraction. The fraction with MW below 1k Da had a higher NDMA yield than that with larger MW. NDMA formation increased as the dissolved organic carbon (DOC) to dissolved organic nitrogen (DON) ratio decreased, which indicated that DON might serve as the real important precursor for NDMA. The correlation between NDMA yield and specific ultraviolet absorbance at 254 nm (SUVA ) suggested that the latter might not represent the specific precursors for NDMA in the water. Besides the water quality, the influences of pH, disinfectant dosage, and disinfection contact time on the formation of NDMA were also examined. These results will help water treatment plants establish measures to control this harmful disinfection by-product.

关键词： N-nitrosodimethylamine (NDMA)     disinfection by-product     dissolved organic nitrogen (DOC)     hydrophilic     molecular weight (MW)     specific ultraviolet absorbance at 254 nm (SUVA254)    

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Mechanistic insight into the biofilm formation and process performance of a passive aeration ditch (PAD

《环境科学与工程前沿（英文）》 2022年 第16卷 第7期 doi: 10.1007/s11783-021-1494-3

摘要：

• A Passive Aeration Ditch was developed to treat decentralized wastewater.

关键词： Decentralized wastewater     Passive aeration ditch     Biofilm formation     C/N ratio     Salinity     Model simulation    

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Is atmospheric oxidation capacity better in indicating tropospheric O formation?

《环境科学与工程前沿（英文）》 2022年 第16卷 第5期 doi: 10.1007/s11783-022-1544-5

摘要：

● This study summarizes and evaluates different approaches that indicate O3 formation.

关键词： O3     AOC     O3 formation regime    

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Formation mechanism and modeling of surface waviness in incremental sheet forming

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0679-1

摘要： Improving and controlling surface quality has always been a challenge for incremental sheet forming (ISF), whereas the generation mechanism of waviness surface is still unknown, which impedes the widely application of ISF in the industrial field. In this paper, the formation mechanism and the prediction of waviness are both investigated through experiments, numerical simulation, and theoretical analysis. Based on a verified finite element model, the waviness topography is predicted numerically for the first time, and its generation is attributed to the residual bending deformation through deformation history analysis. For more efficient engineering application, a theoretical model for waviness height is proposed based on the generation mechanism, using a modified strain function considering deformation modes. This work is favorable for the perfection of formation mechanism and control of surface quality in ISF.

关键词： surface waviness     incremental sheet forming     numerical simulation     formation mechanism     deformation history    

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New insights into the formation of ammonium nitrate from a physical and chemical level perspective

《环境科学与工程前沿（英文）》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1737-6

摘要：

● Factor analysis of ammonium nitrate formation based on thermodynamic theory.

关键词： Ammonium nitrate formation     Thermodynamic theory     Aerosol liquid water content     Source apportionment    

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High-precision standard enthalpy of formation for polycyclic aromatic hydrocarbons predicting from general

《化学科学与工程前沿（英文）》 2022年 第16卷 第12期   页码 1743-1750 doi: 10.1007/s11705-022-2184-9

摘要： The standard enthalpy of formation is an important predictor of the reaction heat of a chemical reaction. In this work, a high-precision method was developed to calculate accurate standard enthalpies of formation for polycyclic aromatic hydrocarbons based on the general connectivity based hierarchy (CBH) with the discrete correction of atomization energy. Through a comparison with available experimental findings and other high-precision computational results, it was found that the present method can give a good description of enthalpy of formation for polycyclic aromatic hydrocarbons. Since CBH schemes can broaden the scope of application, this method can be used to investigate the energetic properties of larger polycyclic aromatic hydrocarbons to achieve a high-precision calculation at the CCSD(T)/CBS level. In addition, the energetic properties of CBH fragments can be accurately calculated and integrated into a database for future use, which will increase computational efficiency. We hope this work can give new insights into the energetic properties of larger systems.

关键词： standard enthalpy of formation     polycyclic aromatic hydrocarbons     connectivity based hierarchy     high-precision calculation    

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标题 作者 时间 类型 操作

Occurrence and removal of

Lin WANG,Yongmei LI,Xiaoling SHANG,Jing SHEN

期刊论文

Characteristics of typical dissolved black carbons and their influence on the formation of disinfection

期刊论文

Unlocked disinfection by-product formation potential upon exposure of swimming pool water to additional

Alvyn P. Berg, Ting-An Fang, Hao L. Tang

期刊论文

Trends of chemical speciation profiles of anthropogenic volatile organic compounds emissions in China, 2005–2020

Wei WEI, Shuxiao WANG, Jiming HAO, Shuiyuan CHENG

期刊论文

四川盆地致密砂岩气藏勘探现状与资源潜力评价

卞从胜,王红军,汪泽成,徐兆辉

期刊论文

Factors influencing the photodegradation of

Bingbing XU, Zhonglin CHEN, Fei QI, Jimin SHEN, Fengchang WU

期刊论文

中国致密油形成分布与资源潜力评价

庞正炼,邹才能,陶士振,杨智,吴松涛

期刊论文

Time-varying formation tracking for uncertain second-order nonlinearmulti-agent systems

Mao-peng RAN, Li-hua XIE, Jun-cheng LI

期刊论文

3D finite element prediction of chip flow, burr formation, and cutting forces in micro end-milling of

A. DAVOUDINEJAD, P. PARENTI, M. ANNONI

期刊论文

Factors controlling

Chengkun WANG, Xiaojian ZHANG, Chao CHEN, Jun WANG

期刊论文

Mechanistic insight into the biofilm formation and process performance of a passive aeration ditch (PAD

期刊论文

Is atmospheric oxidation capacity better in indicating tropospheric O formation?

期刊论文

Formation mechanism and modeling of surface waviness in incremental sheet forming

期刊论文

New insights into the formation of ammonium nitrate from a physical and chemical level perspective

期刊论文

High-precision standard enthalpy of formation for polycyclic aromatic hydrocarbons predicting from general

期刊论文