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Frontiers of Chemical Science and Engineering 2016年第3期10卷 417-424页

作者： guozhen xu Jian Zhang Shengping Wang Yujun Zhao Xinbin Ma Key Laboratory for Green Chemical Technology of Ministry of Education Collaborative Innovation Centre of Chemical Science and Engineering School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

The effect of thermal pretreatment on the active sites and catalytic performances of PtSn/SiO2 catalyst in acetic acid （AcOH） hydrogenation was investigated in this article. The catalysts were characterized by N2 physical adsorption, X-ray diffraction, transmission electron microscopy, pyridine Fourier-transform infrared spectra, and H2-O2 titration on its physicochemical properties. The results showed that Pt species were formed primarily in crystalline structure and no PtSnx alloy was observed. Meanwhile, with the increment of thermal pretreatrnent temperature, Pt dispersion showed a decreas- ing trend due to the aggregation of Pt particles. Simultaneously, the amount of Lewis acid sites was remarkably influenced by such thermal pretreatment owning to the consequent physicochemical property variation of Sn species. Interestingly, the catalytic activity showed the similar variation trend with that of Lewis acid sites, confirming the important roles of Lewis acid sites in AcOH hydrogenation. Moreover, a balancing effect between exposed Pt and Lewis acid sites was obtained, resulting in the superior catalytic performance in AcOH hydrogenation.

关键词： thermal pretreatment acetic acid hydrogenation ethanol PtSn/SiO2

Valency Study of Vanadium in Stone Coal of Southern China

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Rare Metals 1990年第2期10卷 110-116页

作者： xu, guozhen Ge, Nai'e Chen, Jianping Shen, Shaobo Chinese Univ of Geosciences China

Vanadium - bearing stone coal is a new resource of vanadium. V in stone coal mainly exists in three oxidation states: 7.84% V(III), 72.08% V(IV) and 20.08% V(V). The change and distribution of valency during oxidizing roasting shows that organic matter in the coal determines the valency at low temperatures. At about 450°C, V(III) is completely oxidized to V(IV); above 500°C, temperature is the most important factor for the oxidation of V. At 700-1000°C, 92% of V in the coal has been oxidized to V(V). At higher temperature, no more oxidation of V takes place, equilibrium being established. The role of NaCl in the recovery of V2O5 from the coal is discussed. The best conditions for roasting are an oxidation-chlorination atmosphere, temperature 800°C for 30 minutes, ore:NaCl = 100:10, ηroast reaching 90%.

关键词： Coal Deposits Peoples Republic of China Mineral Industry and Resources Peoples Republic of China

Energy-Efficient Beamforming for Two-Tier Massive MIMO Downlink

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China Communications 2015年第10期12卷 64-75页

作者： xu guozhen LIU An JIANG Wei XIANG Haige LUO Wu China Mobile Research Institute & The State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University Department of Electrical and Computer Engineering Hong Kong University of Science and Technology The State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University

Heterogeneous networks(HetNets)consisting of macro cells with very large antenna arrays and a secondary tier of small cells with a few antennas each can well tackle the contradiction of large coverage of the network and high data rate at the hot ***,it is not permissible to assign orthogonal pilot sequences for all the supported users due to the large ***,we propose a pilot reduction scheme based on the heterogeneous system configurations and the unique topology of this *** reusing of pilot sequences causes the presence of the contaminated channel state information(CSI) and results in receivers' Quality of Service(QoS) *** the contaminated CSI,we provide an energy-efficient beamforming based on minimizing the total power consumption while keeping the QoS constraints satisfied and restricting the QoS outage probability below a given *** applying the approach of Bernstein approximation and semi-definite relaxation,we transform the original intractable chance constrained program to a convex problem *** results show that the average power consumption of the proposed beamforming for our pilot reduction scheme is close to that of the perfect CSI *** our scheme will greatly compress the length of pilot sequence especially for those highly densified network with large number of small cells,it will be crucially helpful to put such two-tier massive multiple-input and multiple-output(MIMO) systems into practice.

关键词： massive MIMO small cell Het-Net energy efficiency

Sedimentary Expressions of the Early Jurassic Jenkyns Event in an Inland Lacustrine System in the Yin'gen-Ejinaqi Basin,North China

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Acta Geologica Sinica(English Edition) 2024年第5期98卷 1359-1375页

作者： YANG Bing xu guozhen HUI Guangji WEI Yi ZHANG Xinzhi YI Jinjun SUN Siyuan ZHANG Sujiang Cores and Samples Center of Natural Resources LangfangHebei 065201China Nanjing Institute of Geology and Palaeontology Chinese Academy of SciencesNanjing 210008China North China Institute of Science and Technology LangfangHebei 065201China

The Jenkyns Event,more widely known as the Toarcian Oceanic Anoxic Event(T-OAE),is marked by globally distributed negative carbon-isotope excursions,widespread oxygen depletion,and large-scale organic carbon burial,which indicate major climate/environmental perturbations in Earth's surface systems during the Early *** extensive research has been conducted in European continental settings,particularly in the western peri-Tethys regions,the impacts of this event beyond Europe remains largely ***,a multiapproach study including investigations into the sporepollen assemblages,pyrite framboids,clay minerals,total organic carbon(TOC)levels,and organic carbon isotope(δ13Corg)levels in a lacustrine borehole section(MED1)from the Yin'gen-Ejinaqi Basin,North China,provides evidence of the occurrence of the Jenkyns Event and its extensive sedimentary responses in the eastern Tethys terrestrial *** distinct spore-pollen assemblages have been identified in MED1(drilling depth:982.4 m to 1267.5 m),with the Cycadopites-Protopinus-Osmundacidites assemblage in the lower part(1267.5 m to 1132.9 m)indicating a middle Early Jurassic age and the Classopollis assemblage in the upper part(1132.9 m to 985.7 m)suggesting a Toarcian *** pyrite data suggest more anoxic conditions during the deposition of black mudstone and shale intercalations in the lower part of the Classopollis assemblage(1132.9 m to 1066.9 m),which combined with organic carbon enrichment and negativeδ13Corg excursions,are considered the paleoenvironmental response to the Jenkyns Event in the study ***,the evolution of vegetation groups changed from plant groups characterized by bisaccate and cycad pollen,as well as fern spores,to vegetation groups represented by Cheirolepidiaceae pollen across the Jenkyns Event,as evidenced by sporepollen data,together with the clay mineral assemblage change characterized by a notable increase in illite at the expense of kaolinite,

关键词： spore-pollen assemblages clay minerals pyrite framboids organic carbon isotope Jenkyns event

Discussion　of　Xixia’s　Forestry　A　Model　for　the　Development　of　China’s　Township　Forestry

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Forestry and Society Newsletter 1994年第1期 1-4页

作者： $$$$ xu guozhen

ＤｉｓｃｕｓｓｉｏｎｏｆＸｉｘｉａ’ｓＦｏｒｅｓｔｒｙＡＭｏｄｅｌｆｏｒｔｈｅＤｅｖｅｌｏｐｍｅｎｔｏｆＣｈｉｎａ’ｓＴｏｗｎｓｈｉｐＦｏｒｅｓｔｒｙ￥ｂｙＸｕＧｕｏｚｈｅｎＰｏｖｅｒｔｙｉｓｓｔｉｌｌａｓｅｒｉｏｕ... 详细信息

ＤｉｓｃｕｓｓｉｏｎｏｆＸｉｘｉａ’ｓＦｏｒｅｓｔｒｙＡＭｏｄｅｌｆｏｒｔｈｅＤｅｖｅｌｏｐｍｅｎｔｏｆＣｈｉｎａ’ｓＴｏｗｎｓｈｉｐＦｏｒｅｓｔｒｙ￥ｂｙＸｕＧｕｏｚｈｅｎＰｏｖｅｒｔｙｉｓｓｔｉｌｌａｓｅｒｉｏｕｓｓｏｃｉａｌａｎｄｅｃｏｎｏｍｉ...

关键词： China Model

Joint User Scheduling and Antenna Selection in Distributed Massive MIMO Systems with Limited Backhaul Capacity

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China Communications 2014年第5期11卷 17-30页

作者： xu guozhen LIU An JIANG Wei XIANG Haige LUO Wu The State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University China Department of Electrical and Computer Engineering Hong Kong University of Science and Technology Hong Kong China

Massive MIMO systems offer a high spatial resolution that can drastically increase the spectral and/or energy efficiency by employing a large number of antennas at the base station(BS).In a distributed massive MIMO system,the capacity of fiber backhaul that links base station and remote radio heads is usually limited,which becomes a bottleneck for realizing the potential performance gain of both downlink and *** solve this problem,we propose a joint antenna selection and user scheduling which is able to achieve a large portion of the potential gain provided by the massive MIMO array with only limited backhaul *** sub-optimal iterative algorithms with the objective of sumrate maximization are proposed for the joint optimization of antenna selection and user scheduling,either based on greedy fashion or Frobenius-norm *** and complexity analysis are presented for the *** provided Monte Carlo simulations show that,one of our algorithms achieves a good tradeoff between complexity and performance and thus is especially fit for massive MIMO systems.

关键词： massive MIMO limited backhaul capacity antenna selection user scheduling

Valency Study of Vanadium in Stone Coal Ash of Jiangxi Province

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Journal of Earth Science 1990年第1期9卷 126-134页

作者： xu guozhen Ge Naie Li JiguiDepartment of Basic Courses, China University of Geosciences, Beijing 100083

Vanadium-bearing stone coal is a new vanadium resource; recovery of V2O5 from the coal has been investigated. It has been found that a satisfactory extraction of V2O5 depends on both the oxidation of V and its reaction with sodium salt. V in the coal ash of Yushan mainly exists in two oxidation states; 98% V (Ⅲ) and 2% V(Ⅳ). The distribution of valency of V shows that organic matter determines V valency at low temperatures, at about 470℃ , V(Ⅲ) is completely oxidized to V (Ⅳ); above 500 ℃, the temperature is the most important factor for the oxidation of V At higher temperatures no more V is oxidized to V(Ⅴ); an equilibrium is established after 92% of V is oxidized to V(Ⅴ). The roles of NaCl in the recovery of V2O5 from the coal ash were discussed. The best conditions for roasting are temperature 750-800℃ for 1 h. under the oxidation-chlorination atmosphere. When the ore : NaCl = 100 :10 by weight, ηroast reaches 85.5%. According to the results, a flowsheet for V2O5 extraction from coal ash has been proposed.

关键词： coal ash NaCl / oxidation roasting leaching and extraction the soluble vanadate recovery Jiangxi Province.

Impact of Demographic Structure on Paddy and Forestland Management

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Chinese Forestry Science and Technology 2006年第1期5卷 86-92页

作者： LI Tiehua XIANG Wenhua xu guozhen ZENG Guangzheng School of Resource and Environment Central South University of Forestry and Technology Changsha 410004. P. R. China

In order to understand the impact of demographic structure on paddy and forestland managementafter the convening of the Third Plenary Session of the 11th CPC (Communist Party of China) CentralCommittee and the implementation of the Household Responsibility System (the government divided upland among peasants for cultivating and the peasants sell a set part of their produced goods to thegovernment at stipulated prices by contract in the countryside of China), 147 households in 6 villages,belonging to Xiangtan County and Zhuzhou County in Hunan Province, were selected as research samples,and interview, questionnaire survey and second hand data analyzing were used as the methods. The resultsshowed: Persons with different ages had different ideas, and young peasants would like to work in townsor cities for more income, so they used and depended on land less; In terms of sex, the male was still themain user of land, and therefore the ability, idea and activity of male played an important role in landmanagement; Generally, the labors with better educational background grasped more knowledge andtechnologies, and they had more opportunity to get jobs and had better working condition and moreincome in town or cities, so they depended on and used land less.

关键词： demographic structure paddy and forestland management age structure sex structure educational background China

Community Forestry Is a Development and Innovation to Forestry

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Forestry and Society Newsletter 2002年第2期 1-4页

作者： xu guozhen (For more information,please contact Mr.xu guozhen,South-Central China Forestry College,Zhuzhou,Hunan Province,412006)

The history of human’s social development indicates thatthe progress and development of a society is the resultof the collaborative role of science and technologyadvancement and humane society progress.”Humans live not

关键词： forestry collaborative sustainable humane operational connotation agricultural timber agriculture conception

金融创新与世博会项目融资——美国金融创新实证研究的几点启示

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上海经济研究 2006年第1期18卷 60-64页

作者：徐国贞国家开发银行上海市分行 200120

近几十年来,美国金融衍生产品发展非常迅速,已经形成了多层次、多方式金融资本融合的格局。金融创新是金融业保持活力和提供全面、快捷、高效服务的基础。金融创新不仅能够拓宽金融业务的领域,提高资金融通的效率,增加金融机构的收益,... 详细信息

近几十年来,美国金融衍生产品发展非常迅速,已经形成了多层次、多方式金融资本融合的格局。金融创新是金融业保持活力和提供全面、快捷、高效服务的基础。金融创新不仅能够拓宽金融业务的领域,提高资金融通的效率,增加金融机构的收益,满足客户的需求,降低企业的融资成本,促使借贷双方的选择呈多样化趋势;更重要的是金融创新还有助于规避金融风险,显著降低对冲风险的成本,促使整个金融系统变得更加灵活、有效、富有弹性。本文主要借鉴美国这方面的经验,探索上海世博会的项目融资途径。

关键词：金融创新世博会