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Unperturbed dimensions of atactic poly(dibenzyl itaconate)s

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第7期8卷 991-998页

作者： MA hai-zhu YE Gao-xiang Department of Physics Zhejiang University Hangzhou 310027 China School of Science and Technology Zhejiang Education Institute Hangzhou 310012 China

The unperturbed dimension and temperature character of poly(dibenzyl itaconate)s (PDBzI) are studied by a revised rotational isomeric state (RIS) method. The improved formulas of the mean-square radius of gyration, deduced by the pseudo-stereochemical equilibrium approach, may be used to investigate the configurational-conformational properties of atactic polymers with large side groups [poly(itaconates) for instance]. The calculated results showed that poly(itaconates) have larger dimension of the molecule than other vinyl polymers. Comparison of the dimension between considering and without considering side groups showed that the effect of large side groups on the unperturbed dimension for short-chain polymers is more obvious than that of long-chain polymers and, if the dimension of side groups increases, the effect also increases. The dimension differences of PDBzI between short-chain and long-chain polymers are investigated by the relation of characteristic ratios and temperature coefficients with temperature. Moreover, the dependence between the temperature coefficients and the tacticity of chains shows that the temperature characters of the isotactic, syndiotactic and atactic PDBzI chains have remarkable difference.

关键词： Poly(dibenzyl itaconate)s Mean-square radius of gyration Temperature coefficient Tacticity

Effect of nanocomposite pour point depressant EVAL/CNT on flow properties of waxy crude oil

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Petroleum Science 2023年第6期20卷 3807-3818页

作者： Yang Liu zheng-Nan Sun Sheng-zhu Ji Yi-hai Yang Jian-Qi Xu Guo-Lin Jing Provincial Key Laboratory of Oil&Gas Chemical Technology College of Chemistry&Chemical EngineeringNortheast Petroleum UniversityDaqing163318HeilongjiangChina No.8 Oil Production Plant Engineering Technology Brigade Daqing OilfieldDaqing163514HeilongjiangChina

The nanocomposite EVAL-CNT was produced by chemical grafting in the solution system through the esterification of ethylene-vinyl alcohol copolymer (EVAL) and carboxylated multi-walled carbon nanotubes (O-MWCNT), and its structural properties were characterized. The improvement of the rheological properties of the waxy oil system by the novel pour point depressant was investigated using macroscopic rheological measurements and microscopic observations. The results showed that EVAL-CNT nanocomposite pour point depressant (PPD) could significantly reduce the pour point and improve the low temperature fluidity of crude oil and had better performance than EVAL-GO at the same addition level. The best effect was achieved at the dosing concentration of 400 ppm, which reduced the pour point by 13 ℃ and the low-temperature viscosity by 85.4%. The nanocomposites dispersed in the oil phase influenced the precipitation and crystallization of wax molecules through heterogeneous crystallization templates, which led to the increase of wax crystal size and compact structure and changed the wax crystal morphology, which had a better effect on the rheological properties of waxy oil.

关键词： Pour point depressant Carbon nanotubes Nanocomposites Waxy crude oil Rheological behavior

Tough Polyion Complex Hydrogel Films of Natural Polysaccharides

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Chinese Journal of Polymer Science 2017年第10期35卷 1276-1285页

作者： Feng-bo zhu hai-chao Yu Wen-xi Lei Ke-feng Ren Jin Qian 吴子良 Qiang zheng Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Department of Engineering Mechanics Zhejiang University Ministry of Education Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University

The developments of tough hydrogels in recent years have greatly expanded the applications of hydrogels as structural materials. However, most of the tough hydrogels are made of synthetic polymers. To develop biopolymer-based tough hydrogels has both fundamental and practical significances. Here we report a series of polysaccharides-based tough hydrogel films prepared by polyion complexation and solvent evaporation of chondroitin sulfate（CS） and protonated chitosan（CHT） solutions with different weight ratios. The obtained CS/CHT gel films with thickness of 40-80 μm and water content of 66 wt%-81 wt% possess excellent mechanical properties, with tensile breaking stress and breaking strain being 0.4-3 MPa and 160%-320%, respectively. We found that in the mixture solutions there are large amounts of excess CHT in terms of charges; after swelling the films in water, the acetic acid, which is used to protonate the amino groups of CHT, diffuses out of the gel matrix, enhancing the intermolecular interactions between CHT molecules and thus improving the mechanical properties of gel films, besides the ionic bonds between CS and CHT. Antimicrobial tests also showed that the gel films with low weight ratio of CS to CHT, corresponding to the case with excess CHT, have evident antimicrobial effect. These CS/CHT gel films with good mechanical properties and antimicrobial effect should extend the applications of hydrogels in biomedical fields.

关键词： responsive polymerization methacrylate acrylamide hydrophilic reversible dissipation AMPS toughness swelling

Fe_(n)Co_(55-n)与Co_(n)Mo_(55-n)(n=0~55)团簇基态的能量与结构演化

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原子与分子物理学报 2025年第5期42卷 57-66页

作者：程彪郑琪琪陈轩段海明新疆大学物理科学与技术学院乌鲁木齐830049

采用半经验的Gupta多体势函数结合遗传算法及分子动力学淬火算法,系统研究了Co_(n)Mo_(55-n)(n=0~55)与Fe_(n)Co_(55-n)(n=0~55)团簇的基态结构与能量.通过分析基态结构的相似函数、质心间距、平均键长、平均原子配位数、平均结合能、... 详细信息

采用半经验的Gupta多体势函数结合遗传算法及分子动力学淬火算法,系统研究了Co_(n)Mo_(55-n)(n=0~55)与Fe_(n)Co_(55-n)(n=0~55)团簇的基态结构与能量.通过分析基态结构的相似函数、质心间距、平均键长、平均原子配位数、平均结合能、混合能与二阶差分能.探究了团簇基态的结构特征及稳定性与团簇所含元素种类及组分的关联.结果表明:对Co-Mo混合团簇,随Co原子数目增加,Co原子依次占据团簇中心与最外层顶点,混合团簇逐渐出现组分偏析与无序现象;对Fe-Co混合团簇,基态结构主体上均体现为围绕Mackay二十面体构型的结构畸变,随Fe原子含量增加,Fe原子先占据团簇外表面顶点位置直到全部包裹Co原子,逐渐形成核壳式结构;Co_(13)Mo_(42)与Fe_(42)Co_(13)是幻数结构团簇,研究发现组分效应导致的团簇高对称性相比团簇平均键长与平均原子配位数更能解释幻数结构的成因.

关键词：遗传算法淬火算法双金属团簇基态结构

Convergence of a Non-interior Continuation Algorithm for the Monotone SCCP

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Acta Mathematicae Applicatae Sinica 2010年第4期26卷 543-556页

作者： Nan Lu zheng-hai Huang Department of Mathematics School of ScienceTianjin UniversityTianjin 300072China

It is well known that the symmetric cone complementarity problem（SCCP） is a broad class of optimization problems which contains many optimization problems as special *** on a general smoothing function,we propose in this paper a non-interior continuation algorithm for solving the monotone *** proposed algorithm solves at most one system of linear equations at each *** using the theory of Euclidean Jordan algebras,we show that the algorithm is globally linearly and locally quadratically convergent under suitable assumptions.

关键词： Symmetric cone complementarity problem non-interior continuation method global linear convergence local quadratic convergence

Shipborne radar maneuvering target tracking based on the variable structure adaptive grid interacting multiple model

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第9期14卷 733-742页

作者： zheng-wei zhu School of Information Engineering Southwest University of Science and Technology Mianyang 621010 China

The trajectory of a shipbome radar target has a certain complexity, randomness, and diversity. Tracking a strong maneuvering target timely, accurately, and effectively is a key technology for a shipbome radar tracking system. Combining a variable structure interacting multiple model with an adaptive grid algorithm, we present a variable structure adaptive grid inter- acting multiple model maneuvering target tracking method. Tracking experiments are performed using the proposed method for five maneuvering targets, including a uniform motion - uniform acceleration motion target, a uniform acceleration motion - uni- form motion target, a serpentine locomotion target, and two variable acceleration motion targets. Experimental results show that the target position, velocity, and acceleration tracking errors for the five typical target trajectories are small. The method has high tracking precision, good stability, and flexible adaptability.

关键词： Shipbome radar Target tracking Variable structure Interacting multiple model Adaptive grid algorithm

Superparamagnetic iron oxide nanoparticle targeting of adipose tissue-derived stem cells in diabetes-associated erectile dysfunction

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Asian Journal of Andrology 2017年第4期19卷 425-432页

作者： Lei-Lei zhu zheng Zhang He-Song Jiang hai Chen Yun Chen Yu-Tian Dai Department of Andrology Drum Tower Hospital School of Medicine Nanjing University Nanjing 210008 China

Erectile dysfunction （ED） is a major complication of diabetes, and many diabetic men with ED are refractory to common ED therapies. Adipose tissue-derived stem cells （ADSCs） have been shown to improve erectile function in diabetic animal models. However, inadequate cell homing to damaged sites has limited their efficacy. Therefore, we explored the effect of ADSCs labeled with superparamagnetic iron oxide nanoparticles （SPIONs） on improving the erectile function of streptozotocin-induced diabetic rats with an external magnetic field. We found that SPIONs effectively incorporated into ADSCs and did not exert any negative effects on stem cell properties. Magnetic targeting of ADSCs contributed to long-term cell retention in the corpus cavernosum and improved the erectile function of diabetic rats compared with ADSC injection alone. In addition, the paracrine effect of ADSCs appeared to play the major role in functional and structural recovery. Accordingly, magnetic field-guided ADSC therapy is an effective approach for diabetes-associated ED therapy.

关键词： erectile dysfunction magnetic targeting stem cells superparamagnetic iron oxide nanoparticles

New Family of Exact Solutions and Chaotic Soltions of Generalized Breor-Kaup System in （2＋1）-Dimensions via an Extended Mapping Approach

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Communications in Theoretical Physics 2005年第2X期44卷 203-208页

作者： FANG Jian-Ping zheng Chun-Long zhu hai-Ping REN Qing-Bao CHEN Li-Qun Department of Physics Zhejiang Lishui University Lishui 323000 China Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

Starting from an extended mapping approach, a new type of variable separation solution with arbitrary functions of generalized (2+1)-dimensional Broer-Kaup system (GBK) system is derived. Then based on the derived sol... 详细信息

关键词： extended mapping approach GBK system exact solution chaotic soliton

Range resolution and sampling frequency trade-off for GPS passive radar

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Journal of Systems Engineering and Electronics 2022年第1期33卷 28-37页

作者： ZHANG zhuxian zheng Yu zheng Linhua zhu Peidong College of Electronic Science National University of Defense TechnologyChangsha 410073China College of Electronic Communication and Electrical Engineering Changsha UniversityChangsha 410022China

In a global positioning system(GPS)passive radar,a high resolution requires a high sampling frequency,which increases the computational *** the computational load and the range resolution is *** paper presents a method to trade off the range resolution and the computational load by experimentally determining the optimal sampling frequency through an analysis of multiple sets of GPS satellite data at different sampling *** test data are used to construct a range resolution-sampling frequency trade-off model using least-squares *** theoretical analysis shows that the experimental data are the best fit using smoothing and nthorder derivative *** field GPS C/A code signal-based GPS radar,the trade-off between the optimal sampling frequency is determined to be in the 20461.25–24553.5 kHz range,which supports a resolution of 43–48 *** with the conventional method,the CPU time is reduced by approximately 50%.

关键词： global positioning system(GPS)radar range resolution sampling frequency trade-off