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Statistical study of cement additives with and without chloride on performance modification of Portland cement

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Progress in Natural Science:Materials International 2011年第3期21卷 246-253页

作者： Hong HUANG,Xiao-dong SHEN state key laboratory of Materials-Oriented Chemical Engineering,College of Material Science and Engineering, nanjing university of technology,nanjing 210009,china state key laboratory of Materials-Oriented Chemical Engineering College of Material Science and Engineering Nanjing University of Technology Nanjing 210009 China

The effectiveness of cement additives with and without chloride on the fluidity and the strength development of Portland cement was compared by using statistical full factorial *** experimental results show that the cement additive containing CaCl2and Ca(NO3)2can enhance early strength of cement ***,Ca(NO3)2is less effective than CaCl2even if it is combined with other organic chemicals such as alkanolamine and *** significant difference is found between CaCl2and Ca(NO3)2influencing the fluidity and 28 d strength of *** fluidity is determined by saccharide and its interaction with *** 28 d strength enhancement is determined by *** fluidity as well as the mechanical performance of treated cement can be significantly improved by combining Ca(NO3)2with TIPA and saccharide.

关键词： Portland cement cement additive accelerator type fluidity strength development full factorial design

Analysis of variance for testing method of cement in determination of strength

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Progress in Natural Science:Materials International 2011年第4期21卷 341-346页

The statistical tools such as descriptive statistics,full factorial design and analysis of source of variation were used to identify the potential factors that impact the validity of testing method for determining the strength of *** results showed that personal error impacted both accuracy and precision of test *** time associated with temperature fluctuation resulted in strength variation but did not impact the precision of test in all curing *** compactions did not impact the precision of test but resulted in the strength variation on 3 d and 28 d *** methods for the initial moist air curing significantly impacted the precision of testing method and resulted in the strength variation of cement on 1 d.

关键词： testing method of cement analysis of variance strength accuracy precision

On power allocation for a cognitive radio network with hybrid spectrum sharing

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Science china(Information Sciences) 2011年第11期54卷 2425-2434页

作者： ZHANG Jing 1,2,3 & ZHU HongBo 1 1 key laboratory of Wireless Communications of Jiangsu Province,nanjing university of Posts & Telecommunications,nanjing 210003,china 2 College of Electronic Science & Engineering,nanjing university of Posts & Telecommunications,nanjing 210003,china 3 state key laboratory of Millimeter Waves,nanjing 210096,china 1. key laboratory of Wireless Communications of Jiangsu Province Nanjing University of Posts & Telecommunications Nanjing 210003 China2. College of Electronic Science & Engineering Nanjing University of Posts & Telecommunications Nanjing 210003 China3. State Key Laboratory of Millimeter Waves Nanjing 210096 China

In this study we propose a hybrid spectrum sharing scheme based on power control by combining Overlay with Underlay schemes,to improve radio spectrum *** the scheme,the secondary users dynamically switch their operational states between Overlay and Underlay according to the spectrum *** the dynamics of the primary network is first modeled with a discrete-state Markov process to find the time fraction of secondary users in the Overlay state and that in the Underlay state,which leads to the capacity model of the hybrid spectrum sharing *** the criterion of maximizing capacity,the power allocation of the cognitive network is researched and the optimum power allocation for secondary users is *** a result,the maximum achievable capacity of the cognitive network is *** are given to prove the analysis *** and simulated results indicate that hybrid spectrum sharing based on power control provides a higher capacity than single Overlay and Underlay systems for the cognitive network,i.e.,hybrid spectrum sharing can further improve radio spectrum efficiency.

关键词： cognitive radio network hybrid spectrum sharing primary network dynamics power allocation achievable capacity

Computed tomography of the acoustic nonlinearity parameter B/A for biological tissues via difference frequency wave from a parametric array in reflection mode

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Chinese Science Bulletin 2003年第22期48卷 2427-2430页

作者： WANG Huanlei, ZHU Xiaofeng, GONG Xiufen & ZHANG Dong state key laboratory of Modern Acoustics, Institute of Acoustics, nanjing university, nanjing 210093, china state key laboratory of Modern Acoustics Institute of Acoustics Nanjing University China

Based on the finite amplitude insert-substitu- tion method, a novel technique to reconstruct the acoustic nonlinear parameter B/A tomography for biological tissues in reflection mode via the difference frequency wave generated by a parametric array is developed in this paper. An experimental system is established, and the beam pattern of the difference frequency wave is measured and compared with that excited directly from a transmitter at the same frequency. B/A tomography for several biological tissues including normal and pathological tissues, is experimentally obtained with satisfying quality. Results indicate that B/A imaging using this mode may become a novel modality in ultrasonic diagnosis.

关键词： X线断层摄影术插入置换法生物学超声波诊断

One-step estimation for varying coefficient models

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Science china Mathematics 2005年第2期48卷 198-213页

作者： TANG Qingguo & WANG Jinde Department of Mathematics, nanjing university, nanjing 210093, china Institute of Sciences, PLA university of Science and technology, nanjing 210007, china 1. Department of Mathematics Nanjing University 210093 Nanjing China 2. Institute of Sciences PLA University of Science and Technology 210007 Nanjing China

A one-step method is proposed to estimate the unknown functions in the varying coefficient models, in which the unknown functions admit different degrees of smoothness. In this method polynomials of different orders are used to approximate unknown functions with different degrees of smoothness. As only one minimization operation is employed, the required computation burden is much less than that required by the existing two-step estimation method. It is shown that the one-step estimators also achieve the optimal convergence rate. Moreover this property is obtained under conditions milder than that imposed in the two-step estimation method. More importantly, as only one minimization operation is employed, the full asymptotic properties, not only the asymptotic bias and variance, but also the asymptotic distributions of the estimators can be derived. The asymptotic distribution results will play a key role for making statistical inference.

关键词： varying coefficient model, one-step estimation, asymptotic distribution, optimal convergence rate.

Predicting bioconcentration factor values of organic pollutants based on medv descriptors derived QSARs

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Science china Chemistry 2007年第5期50卷 587-592页

作者： CUI ShiHai1,2, YANG Jing1, LIU ShuShen2,3 & WANG LianSheng2 1 College of Chemistry and Environment, nanjing Normal university, nanjing 210097, china 2 state key laboratory of Pollution Control and Resources Reuse, School of the Environment, nanjing university, nanjing 210093, china 3 key laboratory of Yangtze Aquatic Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji university, Shanghai 200092, china 1. College of Chemistry and Environment Nanjing Normal University Nanjing 210097 China 2. state key laboratory of Pollution Control and Resources Reuse School of the Environment Nanjing University Nanjing 210093 China 3. key laboratory of Yangtze Aquatic Environment Ministry of Education College of Environmental Science and Engineering Tongji University Shanghai 200092 China

The molecular electronegativity-distance vector (MEDV) is employed todescribe the chemical structure of organic *** linear relationships between themolecular descriptors and BCF values are developed by best subset regression and partial leastsquare regression *** main structural factors influencing the bioactivities are -CH2,-X,-Cnot 2 and q2_(LOO) present good estimation ability and stabilityof *** prediction power for external samples is validated by the model developed from thetraining set.

关键词： POPs, BCF, MEDV, QSAR

The Interaction of Cobalt (Ⅲ) Mixed-Ligand Coordination Compound Containing Dipyrido[3,2-a:2′,3′-c] phenazine With Calf Thymus DNA -

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Chinese Chemical Letters 1997年第6期8卷 551-552页

作者： Lan JIN Pin YANG (state key laboratory of Coordination Chemistry, nanjing university, nanjing 210093: Institute of Molecular Science, Shanxi university. Taiyuan 030006) state key Lab. of Coord. Chemistry Nanjing University Nanjing 210093 China Institute of Molecular Science Shanxi University Taiyuan 030006 China

The binding of Co (phen)2dppz3+ to calf thymus DNA,as investigated using absorption spectroscopy. viscosity and electrophoresis measurements,here dppz is dipyrido[3, 2-a: 2'3'-c]phenazine. The compound shows absorption hypochromicity and the specific viscosity increased upon binding to calf thymus DNA The complex is also shown to be more efficient photosensitisers for single strand breaks in plasmid DNA

关键词： phenazine With Calf Thymus DNA Figure Mixed-Ligand Coordination Compound Containing Dipyrido[3,2-a The Interaction of Cobalt

Environmental archaeology of the Dachang region in the Daning Valley,the Three Gorges reservoir region of the Yangtze River,china

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Chinese Science Bulletin 2008年第S1期53卷 140-152页

作者： ZHANG Yun 1 &ZHU Cheng 2 1 state key laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093, china 2 School of Geographic and Oceanographic Sciences,nanjing university,nanjing 210093,china 1. state key laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing 100093 China 2. School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China

Environmental archaeology of archaeological sites on both sides of the Dachang section in the Daning River,the Three Gorges of the Yangtze River,shows that riverbed evolution has a great influence on the distribution of archaeological sites during the prehistorical and historical period,and it restricts human activity and the development of ancient *** investigation,dating data,paleocurrent analysis of 100 gravels on the riverbed and archaeological excavation reveal that the riverbed of the Dachang section developed in the Shuangyantang region during the early stage,after about 30 kaBP it shifted westward gradually and reached the present *** with the westward shift,the focus of ancient culture changed for several *** the Western Zhou Dynasty's period,the east riverbank of the Daning River was the main residential *** the Han Dynasty,along with the westward shift,the living space of ancient people was no longer confined to the east riverbank and the focus of culture moved *** the Zhangjiawan site became the main dwelling *** the late Han Dynasty, the villages were flooded and the ancients had to immigrate to a high *** of the Han and the Jin Dynasties outcropped on the flood plain of the east bank because their surface sediments were eroded by several flood events and the westward shift of the riverbed.

关键词： the Daning River environmental archaeology the Shuangyantang site the Zhangjiawan site tombs of the Han and the Jin Dynasties

Advances in research of sulphide ore textures and their implications for ore genesis

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Progress in Natural Science:Materials International 2006年第10期16卷 1007-1021页

作者： GU Lianxing, ZHENG Yuanchuan, TANG Xiaoqian, WU Changzhi and HU Wenxuan (state key laboratory for Endogenic Metal Deposits Research, Department of Earth Sciences, nanjing university, nanjing 210093, china) [a]state key laboratory for Endogenic Metal Deposits Research Department of Earth Sciences Nanjing University Nanjing China

Important advances in research of sulphide ore textures in recent years have deepened our understanding of ore genesis of related mineral deposits. Pressure solution of sulphide minerals has been suggested as a mechanism for remobilization of ore materials, whereas pressure solution of the gangues is believed to raise the grade of the primary ores. We have known that precipitation of base metal sulphides from fluids prefers crystal and crack surfaces of pyrite to form overgrowth. Therefore, pyrite-bearing embryo beds in a sedimentary sequence can be acted as effective crystal seed beds and are favorable for fluid overprinting to form huge statabound deposits. Texture studies of various sulphides can be used to interpret the entire history of sedimentation, diagenesis, deformation and metamorphism of the ores. The study of chalcopyrite disease in sphalerite has brought about the idea of zone refining, and given a new explanation to metal zonation in massive sulphide deposits. Ductile shearing of sulphide ores may form ore mylonites, which will become oreshoots enriched in Cu, Au and Ag during late-stage fluid overprinting. Despite that various modern analytical techniques are being rapidly developed, ore microscopy remains to be an unreplaceable tool for ore geologists. Combined with these modern techniques, this tool will help accelerate the development of theories on ore genesis.

关键词： pyrite pyrrhotite chalcopyrite pressure sulution overgrowth mylonite.