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Material removal rate in chemical-mechanical polishing of wafers based on particle trajectories

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Journal of Semiconductors 2010年第5期31卷 145-150页

作者：苏建修陈锡渠杜家熙康仁科 Henan institute of Science and Technology Key Laboratory for Precision and Non-Traditional Machining of Ministry of Education Dalian University of Technology

Distribution forms of abrasives in the chemical mechanical polishing（CMP） process are analyzed based on experimental *** the relationships between the wafer,the abrasive and the polishing pad are analyzed based on kinematics and contact *** to the track length of abrasives on the wafer surface,the relationships between the material removal rate and the polishing velocity are *** analysis results are in accord with the experimental *** conclusion provides a theoretical guide for further understanding the material removal mechanism of wafers in CMP.

关键词： chemical mechanical polishing material removal mechanism abrasive material removal rate

Enhancing hydrothermal stability of framework Al in ZSM-5:From the view on the transformation between P and Al species by solid-state NMR spectroscopy

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Chinese Journal of chemical Engineering 2020年第12期28卷 3052-3060页

作者： Lei Han Ying Ouyang Enhui Xing Yibin Luo Zhijian Da State Key Laboratory of Catalytic Materials and Reaction Engineering Research Institute of Petroleum ProcessingSinopecBeijing 100083China

HZSM-5,with good surface acidity and shape selectivity,was reported as hydrocarbon cracking catalyst for multiple decades,however the hydrothermal stability,especially dealumination of tetrahedrally coordinated framework aluminum(TFAl),has been proved extensively as one of the major challenges during reactionregeneration *** was proposed to stabilize TFAl and indeed it enhanced the hydrothermal ***,most of the phosphorus species would remain outside of the zeolite pore,mainly as polyphosphate species,and block the micropore severely,with only a limited portion introduced into the channel being able to interact with *** the pore size by alkali treatment(desilication)is one of the most convinced methods,but the details about specific P species during alkali treatment and its transformation upon hydrothermal activation is not acquired,thus the mechanism has not been fully ***,the P-containing species and its transformation during direct P modification and acid/alkali treatment followed by Pmodification have been studied,and the mechanism on the interaction between P and Al species has been investigated,using several analytical methods,especially Solid-state nuclear magnetic resonance(SSNMR)*** was found that the combination of desilication and subsequent phosphorus modification can enhance the activity of the ZSM-5 for the cracking of ethylcyclohexane,due to the better hydrothermal stabilization of acid sites by the enhanced interaction between phosphorus and TFAl,resulting from the improved accessibility of TFAl because of the successful generation of *** the acid treatment followed by phosphorus modification,with declined retention of crystallinity and P/Al ratio,monoclinic/orthorhombic transition during steam activation,and the failed generation of mesopores,would cause obvious aggregation of the phosphorus species and could not improve the hydrothermal stability of the ZSM-5 ef

关键词： Phosphorus modification TFAl NaOH/alkali treatment Interaction ZSM-5

New technology of ionic liquid-based NH3/CO2 separation from melamine tail gas

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Green chemical Engineering 2020年第1期1卷 5-5页

作者： Shaojuan Zeng Haifeng Dong Yinge Bai Xiangping Zhang Suojiang Zhang CAS Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemBeijing Key Laboratory of Ionic Liquids Clean ProcessInstitute of Process EngineeringChinese Academy of SciencesBeijing100190China

Melamine is an important industrial raw material,and widely used in the production of thermal insulation materials,adhesives,fiber materials and so ***,every 1 ton of melamine produced through decomposition and condensation reaction using urea generates about 2.2 tons of tail gas containing about 70%NH_(3)and 29%CO_(2).According to the phase diagram of NH_(3)–CO_(2)-AM(ammonium carbamate),NH_(3)and CO_(2)are easy to react and form AM solid under 63C at ambient pressure,which make it difficult to selective recovery of NH_(3).Water scrubbing is the mostly used technology in industries,but this method demands high energy consumption and discharges a large amount of NH_(3)-containg wastewater,which seriously restricts the sustainable development of industries.

关键词： insulation ambient restrict

Natural aging mechanism of buried polyethylene pipelines during long-term service

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Petroleum Science 2023年第5期20卷 3143-3156页

作者： Ying-Chun Chen Yan-Feng Li Yan Xi Qiang Li Qi Lu Jie Yang Beijing University of Technology Beijing100124China Xinjiang Inspection institute of Special Equipment Urumqi830011XinjiangChina

Currently,accelerated aging tests are widely used to study the aging process of polyethylene ***,this approach can only simulate one or several main influencing factors in the natural environment,which are often quite different from the actual environment of the buried *** this study,five types of PE80 buried pipelines in service for 9e18 years were taken as the research object,while new PE80 pipelines were taken as the reference *** aging process and mechanism of polyethylene buried pipelines were studied through mechanical and chemical property tests and microstructural *** results showed that the pipeline exhibited cross-linking as the main aging mechanism after being in service for 0e18 *** aging degree and law of the inner and outer surface of the pipeline were compared,and the observed mechanism of both surfaces was *** 18 years in service,the elongation at the break of the pipe decreased by 16.2%,and the toughness of the matrix in the main collapse area of the tensile sample was the fundamental reason responsible for changes in the mechanical ***,after 18 years in service,the oxidation induction time of the pipeline was 25.7 min,which was 28.5% higher than the national standard *** were no potential safety hazards during continuous long-term *** results of this paper provide reference data and theoretical guidance for the aging process study of buried polyethylene pipelines.

关键词： Polyethylene Buried pipelines Long-term service Natural aging

Hydrogen peroxide and applications in green hydrocarbon nitridation and oxidation

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Chinese Journal of chemical Engineering 2022年第1期35卷 145-161页

作者： Yanqiang Shi Yuetong Xia Guangtong Xu Langyou Wen Guohua Gao Baoning Zong State Key Laboratory of Catalytic Materials and Reaction Engineering Research Institute of Petroleum ProcessingSinopecBeijing 100083China

Basic organic chemicals and high value–added products are mainly produced by hydrocarbon nitridation and ***,several drawbacks limit the application of the traditional oxidation and nitridation technologies in the future,such as complex processes,poor intrinsic safety,low atom utilization,and serious environmental *** green nitridation and oxidation technologies are urgently *** peroxide,a well–known green oxidant,is widely used in green hydrocarbon oxidation and *** its industrial production in China adopts fixed–bed technology,which is fall behind slurry–bed technology adopted by advanced foreign chemical companies,limiting the development of hydrogen peroxide industry and green hydrocarbon nitridation or oxidation *** article reviews the industrial production technologies of hydrogen peroxide and basic organic chemicals such as caprolactam,aniline,propene oxide,epichlorohydrin,phenol,and benzenediol,especially introduces the green production technologies of basic organic chemicals related with H_(2)O_(2).The article also emphasis on the efforts of Chinese researchers in developing its own slurry–bed technology of hydrogen peroxide production,and corresponding green hydrocarbon nitridation or oxidation technologies with hydrogen *** with traditional nitridation or oxidation technologies,green production technologies of caprolactam,propene oxide,epichlorohydrin,and benzenediol with hydrogen peroxide promote the nitrogen atom utilization from 60%to near 100%and the carbon atom utilization from 80%to near 100%.The waste emissions and environmental investments are reduced *** blockade against the green chemical industry of China are partially broken down,and technological upgrade in the chemical industry of China is guaranteed.

关键词： Hydrogen peroxide Green chemical process Partial oxidation Nitridation

Reduction of Low-grade Manganese Dioxide Ore Pellets by Biomass Wheat Stalk

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Acta Metallurgica Sinica(English Letters) 2013年第2期26卷 167-172页

作者： Honglei ZHANG Guocai ZHU Hong YAN Yuna ZHAO Tiancheng LI Xiujuan FENG College of Life Science and Bio-engineering Beijing University of Technology institute of Nuclear and New Energy Technology Tsinghua University

An investigation on reducing low-grade manganese dioxide ore pellets was carried out by using wheat stalk as reductant. The main impact factors of reduction percent such as particle size, biomass/ore ratio, heating rate, nitrogen flow rate, temperature and time in reduction process were discussed. The morphology and component of manganese dioxide ore particle at different stages were also analyzed by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDS）. The results show the increase of the reduction temperature and time, biomass/ore ratio, and the decrease of particle size, heating rate and nitrogen flow rate can significantly enhance reduction efficiency. The reduction kinetic of the manganese ore is controlled by three-dimensional mass diffusion of gaseous reductive volatiles passing from the surface to the core of the ore particles. The activation energy E and frequency factor A were calculated to be 24.15 ***^-1 and 166 min^-1, respectively. Biomass pyrolysis volatiles adsorbed onto the surface of the ore particle leads to serious variation of the microstructures and chemical composition of the manganese ore particles.

关键词： Biomass Reduction Manganese oxide ore Kinetics

Forward osmosis coupled with lime-soda ash softening for volume minimization of reverse osmosis concentrate and CaCO_(3) recovery: A case study on the coal chemical industry

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Frontiers of Environmental Science & Engineering 2021年第1期15卷 135-144页

作者： Jiandong Lu Shijie You Xiuheng Wang State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin 150090China

Reverse osmosis(RO)is frequently used for water reclamation from treated wastewater or desalination *** RO concentrate(ROC)produced from the coal chemical industry(CCI)generally contains refractory organic pollutants and extremely high-concentration inorganic salts with a dissolved solids content of more than 20 g/L contributed by inorganic ions,such as Na^(+),Ca^(2+),Mg^(2+),Cl^(−),and SO_(4)^(2−).To address this issue,in this study,we focused on coupling forward osmosis(FO)with chemical softening(FO-CS)for the volume minimization of CCI ROC and the recovery of valuable resources in the form of CaCO_(3).In the case of the real raw CCI ROC,softening treatment by lime-soda ash was shown to effectively remove Ca^(2+)/Ba^(2+)(>98.5%)and Mg^(2+)/Sr^(2+)/Si(>80%),as well as significantly mitigate membrane scaling during *** softened ROC and raw ROC corresponded to a maximum water recovery of 86%and 54%,*** cyclic FO tests(4×10 h),a 27%decline in the water flux was observed for raw ROC,whereas only 4%was observed for softened *** cleaning efficiency using EDTA was also found to be considerably higher for softened ROC(88.5%)than that for raw ROC(49.0%).In addition,CaCO3(92.2%purity)was recovered from the softening sludge with an average yield of 5.6 kg/m^(3) treated *** study provides a proof-of-concept demonstration of the FO-CS coupling process for ROC volume minimization and valuable resources recovery,which makes the treatment of CCI ROC more efficient and more economical.

关键词： Coal chemical industry Forward osmosis chemical softening Reverse osmosis concentrate

Metamorphic Skarns in the Yangla Cu Ore Field,Northwest Yunnan Province,China

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Journal of Earth Science 2018年第3期29卷 508-519页

作者： Yanxiong Mei Zhenfei Zhang Yuanjin Xu Cheng Luo institute of Mineral Resources Chinese Academy of Geological SciencesBeijing 100037China institute of Mathematical Geology and Remote Sensing China University of GeosciencesWuhan 430074China Mining Development Co.Ltd. DiqingShangrila 674400China

The Yangla Copper Ore Field in Northwest Yunnan Province, China, is a large region of deposits dominated by copper-bearing skarns whose origin remains debatable despite numerous studies over the past two decades. We have investigated the geological and geochemical characteristics of the skarns using field and microscopic observations combined with chemical analyses. The results show that the skarns fall into two categories. The first category is metamorphic skarn, which constitute the majority （〉90%） of skarns in the deposit and is characterized by stratiform occurrences conformable to Devonian host strata, anhydrous mineral assemblages such as diopside＋hedenbergite＋quartz, widespread banded structure, fine-grainsize （〈200 μm） and preserved tuff-like textures. Whole-rock major element compositions, REE and trace-element compositions resemble those of the country rock slates or schists. The skarn layers occur at variable distances （0-2 000 m） from Indosinian plutonic bodies. Fracture-filling veins and/or alteration halos are scarce or absent in or near the skarn layers. This category of skarn probably formed by isochemical contact metamorphism of fine calcareous clastic sediments or impure carbonate rocks during emplacement of the plutonic bodies with no significant material migration by hydrothermal fluids involved during the process, in which case metallic enrichment of the skarn layers was present in the protolith of the skarn. The second category is metasomatic skarn with relatively coarse-grained textures （200-〉1 000 μm） and volatile-reach assemblages such as diopside＋tremolite＋scapolite at or near the igneous contact zones, which constitutes only a minor pro-portion of ore compared with metamorphic skarn. Taking into consideration diverse existing opinions about the genetic type of the deposit, we suggest that the geological and whole-rock geochemical characteristics of the skarus are consistent with a metamorphosed and metasomatized SEDEX （sedimentary exhalati

关键词： metamorphic skarn mineral deposit Yangla Copper Ore Field ore genesis.

Technology of Iron Carbide Synthesis

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Journal of Materials Science & Technology 2006年第3期22卷 423-432页

作者： M.Bahgat Central Metallurgical Research and Development institute (CMRDI) P.O.Box 87-Helwan Cairo 11421 Egypt

Iron carbides are very promising metallurgical products and can be used for steelmaking process, where it plays as an alternative raw material with significant economic advantages. Also it has many other applications, e.g. catalysts, magnets, sensors. The present review investigates the different properties and uses of the iron carbides. The commercial production and the different varieties for the iron carbides synthesis （gaseous carburization, mechanochemical synthesis, laser pyrolysis, plasma pyrolysis, chemical vapor deposition and ion implantation） were reviewed. Also the effect of different factors on the carburization process like gas composition, raw material, temperature, reaction time, catalyst presence and sulfur addition was indicated.

关键词： Iron carbides Cementite Carburization Reduction