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Megacrysts in the Cenozoic basalt of the Tuoyun Basin,Southwest Tianshan

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Science China Earth Sciences 2007年第1期50卷 55-66页

作者： lÜ yongjun lUO ZhaoHua REN ZhongBao lIANG Tao State Key laboratory of Geological Processes and Mineral Resources China University of GeosciencesBeijing 100083China

Abundant megacrysts of clinopyroxene, amphibole, anorthoclase, and phlogopite are found together with deep-seated xenoliths in the Cenozoic basalt of the Tuoyun Basin, Southwest Tianshan. The megacrysts are mainly in the cone sheet formed at the early stage of the volcanic activity. Clinopyroxene megacrysts are located in the lower part of the profile, with amphibole and phlogopite megacrysts in the middle part and anorthoclase megacrysts in the upper part. The crystal integrity, absence of deformation fabric and their relation to the host basalt suggest that they were crystallized from the host magma and quickly transported to the surface. The mineralogical studies imply that the clinopyroxene megacrysts are of Al-augite with higher Al2O3 (>9%). Amphibole megacrysts are kaersutite rich in TiO2 (>4.5%). Sulfide inclusions such as pyrrhotite occur in some clinopyroxene and amphibole megacrysts. Thermodynamic calculations reveal that pyroxene megacrysts formed under the temperature of 1185.85–1199.85°C and the pressure between 1.53 and 1.64 GPa comparable to the crust-mantle boundary and amphibole megacrysts crystallized under the pressure of around 0.85 GPa, temperature about 1000°C comparable to the depth of 30 km. Anorthoclase megacrysts crystallized under the pressure between 0.8–1 GPa, temperature about 900°C. The absence of Ti-rich inclusions such as rutile can be considered as an evidence of quick magma ascending. The P-T conditions estimated via pyroxene megacrysts and phenocrysts compose a P-T path with a steep slope. It can be considered as another evidence of quick magma ascending. However, the estimated temperatures for amphibole megacrysts are markedly lower than those for pyroxene megacrysts given the same pressure. It probably shows that the amphiboles have crystallized at the vanguard of magma and under the volatile-rich condition. Thus, we can conclude that the Cenozoic basalts are produced in an extensional tectonic setting and the processes governin

关键词： Tuoyun Basin megacryst clinopyroxene amphibole anorthoclase alkaline basalt Tianshan.

A molecular dynamics study on surface properties of supercooled water

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Science China(Physics,Mechanics & Astronomy) 2006年第5期49卷 616-625页

作者： lü yongjun & WEI Bingbo Department of Applied Physics, Northwestern Polytechnical University, Xi’an 710072, China Department of Applied Physics Northwestern Polytechnical University Xi’an 710072 China

Molecular dynamics simulations were performed to study the surface properties of water in a temperature range from 228 to 293 K by using the extended simple point charge (SPC/E) and four-site TIP4P potentials. The calculated surface tension increases with the decrease of temperature, and moreover the slopes of the surface tension-temperature curves show a weak rise below 273 K, whereas no obvious anomalies appear near 228 K, which accords with the previous experiments. Compared with the measured values, the SPC/E potential shows a good agreement, and the TIP4P potential underestimates the surface tension. The main reason for that may be the reasonable description of the surface structure of supercooled water for the SPC/E. When simulating the orientational distributions of water molecules near the surface, the SPC/E potential produces higher ordering and larger surface potentials than the TIP4P potential.

关键词： surface tension supercooled water molecular dynamics simulation.

A molecular dynamics study on melting point and specific heat of Ni_3Al alloy

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Science China(Physics,Mechanics & Astronomy) 2007年第4期50卷 407-413页

作者： YANG Hong,lü yongjun,CHEN Min & GUO ZengYuan Department of Engineering Mechanics,Tsinghua University,Beijing 100084,China Department of Engineering Mechanics Tsinghua University Beijing 100084 China

Using the Embedding Atom Method(EAM)for highly undercooled Ni3Al alloy,the melting point and the specific heat were studied by a molecular dynamics *** simulation of melting point was carried out by means of the sandwich method and the NVE ensemble method,and the results show a good agreement,whereas are larger than the experimental value of 1663 *** difference is attrib-uted to the influence of surface melting on experimental results,which causes the smaller measurements compared with the thermodynamic melting *** simulated specific heat of Ni3Al alloy weakly and linearly increases with the in-crease of undercooling in the temperature range from 800 K to 2000 K.

关键词： Ni3Al alloy undercooled melting point specific heat

Petrogenesis of the Paleoproterozoic Guandishan Granitoids in Shanxi Province:Constraints from Geochemistry and Nd Isotopes

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Acta Geologica Sinica(English Edition) 2006年第6期80卷 925-935页

作者： lIU Chaohui lIU Shuwen lI Qiugen lü yongjun K. H. PARK Y. S. SONG The Key laboratory of Orogenic Belts and Crustal Evolution Ministry of Education School of Earth and Space Sciences Peking University Beijing 100871 China Department of Environmental Geosciences Pukyong National University 599-1 Dayeong-dong Nam-gu Busan 608-737 Korea

The Guandishan granitoids consist mainly of various granitoid intrusions with different scales, including the Huijiazhuang intrusion, Shizhuang intrusion and Hengjian intrusion, which were formed between 1906 Ma and 1848 Ma. On the basis of geological and petrological characteristics, these granitoids can be classified into two groups： the earlier gneissic granodiorites and monzogranites, and the later massive leuco-monzogranites. Their geochemical and Nd isotopic features indicate that they could be derived from complicated partial melting of supracrustal rocks with an affinity of continental arc materials, such as sandy shale and pelite, and with garnet, pyroxene, hornblende and plagioclase as residual phases. Biotite, feldspar and other minerals were most likely fractionated during the magma evolution. Their source may have an affinity with continental arcs, and the granitoids could be derived from the main syn-collisional to late-orogenic tectonic environment, which may be related to the final amalgamation between the Eastern and Western continental blocks in the North China Craton.

关键词： granitoids geochemistry Sm-Nd isotopes petrogenesis Paleoproterozoic Guandishan

Geochemistry,Nd Isotopic Characteristics of Metamorphic Complexes in Northern Hebei:Implications for Crustal Accretion

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Acta Geologica Sinica(English Edition) 2006年第6期80卷 807-818页

作者： lIU Shuwen TIAN Wei lü yongjun lI Qiugen FENG Yonggang K. H. PARK Y. S. SONG The Key laboratory of Orogen-ic Belis and Crustal Evolution Ministry of Education China School of Earth and Space Sciences Peking University Beijing 100871 China Department of Environmental Geosciences Pukyong National University 599-1 Dayeong-dong Nam-gu Busan 608-737 Korea

The middle segment of the northern margin of the North China Craton （NCC） consists mainly of metamorphosed Archean Dantazi Complex, Paleoproterozoic Hongqiyingzi Complex and unmetamorphosed gabbro-anorthosite-meta-alkaline granite, as well as metamorphosed late Paleozoic mafic to granitoid rocks in the Damiao-Changshaoying area. The -2.49 Ga Dantazi Complex comprises dioritic-trondhjemitic-granodoritic-monzogranitic gneisses metamorphosed in amphibolite to granulite facies. Petrochemical characteristics reveal that most of the rocks belong to a medium- to high-potassium calc-alkaline series, and display Mg^# less than 40, right-declined REE patterns with no to obviously positive Eu anomalies, evidently negative Th, Nb, Ta and Ti anomalies in primitive mantlenormalized spider diagrams, εNd（t）=＋0.65 to -0.03, and depleted mantle model ages TDM=2.78-2.71 Ga. Study in petrogenesis indicates that the rocks were formed from magmatic mixing between mafic magma from the depleted mantle and granitoid magma from partial melting of recycled crustal mafic rocks in a continental margin setting. The 2.44-2.41 Ga Hongqiyingzi Complex is dominated by metamorphic mafic-granodioritic-monzogranitic gneisses, displaying similar petrochemical features to the Dantazi Complex, namely medium to high potassium calc-alkaline series, and the mafic rocks show evident change in lIlEs, negative Th, Nb, Ta, Zr anomalies and positive P anomalies. And the other granitiod samples also exhibit negative Th, Nb, Ta, P and Ti anomalies. All rocks in the Hongqiyingzi Complex show right-declined REE patterns without Eu anomaly. The metamorphic mafic rocks with εNd（t） = -1.64 may not be an identical magmatic evolution series with granitoids that have εNd（t） values of ＋3.19 to ＋1.94 and TDM ages of 2.55-2.52 Ga. These granitic rocks originated from hybrid between mafic magma from the depleted mantle and magma from partial melting of juvenile crustal mafic rocks in an island arc setting. All the -311 Ma late

关键词： Dantazi Complex Hongqiyingzi Complex late Paleozoic geochemistrv. Nd isotone. wcrustal accretion North China Craton

Geochemistry and Petrogenesis of Neoarchean Metamorphic Mafic Rocks in the Wutai Complex

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Acta Geologica Sinica(English Edition) 2006年第6期80卷 899-911页

作者： lü yongjun lIU Shuwen Guochun ZHAO lI Qiugen Jian ZHANG lIU Chaohui K. H. PARK Y. S. SONG The Key laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University Beijing 100871 China Department of Earth Sciences The University ofHong Kong Pokfulam Road Hong Kong China Department of Environmental Geosciences Pukyong National University 599-1 Dayeong-dong Nam-gu Busan 608-737 Korea

Neoarchean metamorphic mafic rocks in the lower and the middle Wutai Complex mainly comprise metamorphic gabbros, amphibolites and chlorite schists. They can be subdivided into three groups according to chondrite normalized REE patterns. Rocks in Group #1 are characterized by nearly flat REE patterns （lan/Ybn=0.86-1.3）, the lowest total REEs （29-52 ppm）, and weak negative to positive Eu anomalies （Eun/Eun=0.84-1.02）, nearly flat primitive mantle normalized patterns and strong negative Zr（Hf） anomalies. Their geochemical characteristics in REEs and trace elements are similar to those of ocean plateau tholeiite, which imply that this group of rocks can represent remnants of Archean oceanic crust derived from a mantle plume. Rocks in Group #2 are characterized by moderate total REEs （34-116 ppm）, lREE-enriched （lan/Ybn=1.76-4.34） chondrite normalized REE patterns with weak Eu anomalies （Eun/Eun=0.76-1.16）, and negative Nb, Ta, Zr（Hf）, Ti anomalies in the primitive mantle normalized spider diagram. The REE and trace element characteristics indicate that they represent arc magmas originating from a sub-arc mantle wedge metasomatized by slab-derived fluids. Rocks in Group #3 are characterized by the highest total REEs （61-192 ppm）, the strongest lREEs enrichment （lan/Ybn=7.12-16） with slightly negative Eu anomalies （Eun/Eun=0.81-0.95） in the chondrite normalized diagram. In the primitive mantle normalized diagram, these rocks are characterized by large negative anomalies in Nb, Ta, Ti, negative to no Zr anomalies. They represent arc magmas originating from a sub-arc mantle wedge enriched in slab-derived melts. The three groups of rocks imply that the formation of the Neoarchean Wutai Complex is related to mantle plumes and island-arc interaction.

关键词： metamorphic mafic rocks geochemistry petrogenesis Wutai Complex central tectonic zone North China Craton

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基于敏感信息邻近抵抗的匿名方法

计算机工程 2020年第12期46卷 142-149,184页

作者：桂琼吕永军程小辉桂林理工大学信息科学与工程学院广西桂林541004 武汉理工大学信息工程学院武汉430070

针对相似性攻击造成隐私泄露的问题,构建一种(r,k)-匿名模型,基于敏感属性语义关联,设定邻近抵抗阈值r,并提出满足该模型的匿名方法GDPPR。采用模糊聚类技术完成簇的划分,结合敏感属性相异度得出距离矩阵,使得每个等价类中相邻语义下的... 详细信息

针对相似性攻击造成隐私泄露的问题,构建一种(r,k)-匿名模型,基于敏感属性语义关联,设定邻近抵抗阈值r,并提出满足该模型的匿名方法GDPPR。采用模糊聚类技术完成簇的划分,结合敏感属性相异度得出距离矩阵,使得每个等价类中相邻语义下的敏感属性取值频率不高于阈值r,同时保证较高的数据可用性。在两个标准数据集上的实验结果表明,该方案能够较好地满足(r,k)-匿名模型,有效抵抗相似性攻击,减少泛化产生的信息损失。

关键词：数据匿名相似性攻击模糊聚类邻近抵抗数据泛化

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基于MaxEnt模型的胡杨潜在适生区预测

林业科学 2019年第12期55卷 133-139页

作者：厉静文郭浩王雨生辛智鸣吕永军中国林业科学研究院荒漠化研究所北京100091 山东师范大学地理与环境学院济南250358 中国林业科学研究院沙漠林业实验中心磴口015200

【目的】利用最大熵生态位模型(MaxEnt)预测胡杨潜在分布区,以期确定胡杨在我国的潜在分布区,为其合理引种栽培、资源保护利用及可持续管理提供科学依据。【方法】通过文献查找、数据库检索、实地调查等,获取我国胡杨的分布点。根据胡... 详细信息

【目的】利用最大熵生态位模型(MaxEnt)预测胡杨潜在分布区,以期确定胡杨在我国的潜在分布区,为其合理引种栽培、资源保护利用及可持续管理提供科学依据。【方法】通过文献查找、数据库检索、实地调查等,获取我国胡杨的分布点。根据胡杨生长区的环境特点和其自身生长特性,确定各分布点的气候、土壤、地形等29个环境因子,并将环境因子进行多重组合,筛选出影响胡杨潜在分布的主要限制因子,确定相关阈值并据此预测胡杨的潜在分布范围,同时利用受试者工作特征曲线检验模型精度。【结果】从本研究涉及指标来看,我国胡杨潜在分布的适宜区为132.83万km^2,占全国陆地总面积的14.8%;潜在分布区为新疆维吾尔自治区、内蒙古自治区、甘肃省和宁夏回族自治区;最适宜区为新疆中南部和内蒙古西部的额济纳旗,总面积为23.12万km^2,占全国陆地总面积的2.4%;其中新疆的最适宜区面积为22.42万km^2,占全国最适宜区面积的96%;影响胡杨潜在分布的环境因子主要包括最湿月降水量、海拔、年降水量、年均气温、气温年较差和气温季节差,其中最湿月降水量是最重要因子。【结论】胡杨最适宜分布的气候条件是年均气温9.4~11℃、极端最高气温39.2~44℃、极端最低气温-17^-25℃、年降水量32.9~43.7 mm,土壤pH值为7.9~8.5,海拔约1000 m。研究结果利于合理规划胡杨的引种栽培区,避免盲目引种造成人力、物力和财力的浪费,可为我国未来胡杨引种栽植及可持续管理提供科学依据。

关键词：胡杨最大熵模型环境因子适生区潜在分布适宜性评价

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酶在有序介孔材料上的固定化

化学进展 2008年第7期20卷 1172-1179页

作者：吕勇军李佩晋郭杨龙王艳芹卢冠忠结构可控先进功能材料及其制备教育部重点实验室华东理工大学工业催化研究所上海200237

本文回顾了近年来有序介孔材料用于酶的固定化的研究进展;对比了不同固定化方法对介孔材料固定化酶活性的影响以及各种固定化方法的优缺点;分析了影响酶在有序介孔材料上的固定化因素,并分别对这些影响因素进行了讨论;对酶在有序介孔材... 详细信息

本文回顾了近年来有序介孔材料用于酶的固定化的研究进展;对比了不同固定化方法对介孔材料固定化酶活性的影响以及各种固定化方法的优缺点;分析了影响酶在有序介孔材料上的固定化因素,并分别对这些影响因素进行了讨论;对酶在有序介孔材料上固定化的发展和潜在的应用进行了讨论,指出介孔材料固定化酶的潜在应用。

关键词：有序介孔材料酶固定化