一种支持云计算的遥感影像数据组织模型研究

当主用户和次用户在地理上存在一定距离时,由于次用户到达主用户系统的信号不同步,会产生异步干扰,此干扰不但影响主用户系统,使得其干扰增大,也会影响次用户系统,使得次用户系统传输速率损失,特别是误比特性能上升。为了消除异步干扰对主次用户系统的影响,提出了一种基于最小均方误差的预编码方法,此方法在预编码阶段就预先消除了异步干扰,并且是在保证主用户的服务质量基础上进行的。通过分析和仿真结果表明,所提方案在对主用户系统干扰受限的条件下,有效提升了次用户系统和次用户系统的容量,同时提高了次用户系统传输的可靠性。     

Preparation of cobalt ferrite nanoparticles by using spent Li-ion batteries

Cobalt ferrite nanoparticles are a soft magnetic material have been extensively used in many electronic and magnetic applications. In this study, Co_0.8Fe_2.2O₄ nanoparticles with particle size of about 23.5 nm were directly synthesized by sol–gel auto-combustion and calcination methods using spent Li-ion batteries as raw materials. The overall process involves four steps: formation of homogeneous sols; formation of dried gels; combustion of the dried gels; and calcination of the dried gels after combustion at 1173 K for 2 h. The DTA–TG and IR were used to study the auto-combustion and thermal decomposition of the precursor, the morphology and structure of cobalt ferrite nanoparticles were characterized by XRD and TEM techniques. Moreover, the precise metal ion stoichiometry of cobalt ferrite nanoparticles was analyzed by ICP. The results revealed that the auto-combustion process was considered as a heat-induced exothermic oxidation–reduction reaction between nitrate ions and carboxyl group. The XRD patterns of calcination the dried gels after combustion confirmed the single phase spinel structure for the synthesized materials. The crystallite size was calculated from the most intense peak (3 1 1) using the Scherrer equation. The TEM photograph also shown that cobalt ferrite nanoparticles were well-dispersed and with little aggregation.     

求解马鞍点的两种算法及性能分析

求解矩阵中的马鞍点是计算机程序设计中的常见问题。结合矩阵中马鞍点的特点,给出了求解矩阵中的马鞍点的依次搜索法和多马鞍点相等法,详细叙述了它们的算法思想,特别对多马鞍点相等法的理论基础做了证明,分别给出了对应的算法。最后针对这两种算法进行了时间性能和空间性能的分析和比较,总结了两种算法各自的优缺点。     

乙肝疫苗苦参素拉米夫定联合治疗慢性乙型肝炎的临床研究

目的探讨乙肝疫苗苦参素拉米夫定联合治疗慢性乙型肝炎的临床疗效。方法随机选择62例慢性乙型肝炎患者分为治疗组31例,苦参素0.2tidpo。疗程7～9个月,乙肝疫苗60ug,每15天1次,皮下注射,疗程12个月,拉米夫定0.1qdpo.疗程12个月。对照组31例单用拉米夫定0.1qdpo。疗程12个月。疗程中定期检测血常规、谷丙转氨酶(ALT)、HBeAg、抗-HBe、HBV、DNA。结果全部患者完成1年治疗。治疗组ALT复常率,HBeAg/抗-HBe血清转换率、HBVDNA阴转率明显高于对照组(分别为80.6%和51.6%,P<0.05;45.2%和19.4%,P<0.05;77.4%和51.6%,P<0.05)。结论乙肝疫苗、苦参素、拉米夫定联合治疗慢性乙型肝炎疗效优于单用拉米夫定。     

医用镁合金微弧氧化/有机复合涂层的研究现状及演进方向

医用镁及镁合金过快的降解速率严重缩短了其有效服役时间，过高的析氢速率引发局部炎症，束缚了其临床应用前景。微弧氧化（MAO）/有机复合涂层良好的抑蚀降析性能，在医用镁及镁合金表面改性领域展现出巨大的应用潜力。首先，从有机材料（植酸（PA）、壳聚糖（CS）、硬脂酸（SA）、多巴胺（DA）、聚乳酸-乙醇酸共聚物（PLGA）、聚乳酸（PLA）、聚已内酯（PCL））自身的组织及性能特征入手，分析了单一有机涂层提高镁及镁合金耐蚀性的作用机理，并指出单一涂层自身的性能弱点（单一MAO涂层微孔和裂纹的不可避免，单一有机涂层与镁合金结合强度低，易于剥落）限制了对镁合金降解保护效能。其次，从结合强度、耐蚀性、多功能性（生物安全性、生物相容性、诱导再生性、抑菌抗菌性、载药缓释性等）的角度，详细阐述了各MAO/有机复合涂层的结构特点、优势特征。在此基础上，明确指出以MAO/PCL(MAO/CS)复合涂层为基底涂层，通过PCL(CS)涂层与其他涂层的交叉组合，是实现医用镁合金植入材料的生物活性及多功能性的最佳路径。最后，对镁合金MAO/有机复合涂层的演进方向进行了科学展望。     

Systematic parameter estimation for PEM fuel cell models

The problem of parameter estimation is considered for the case of mathematical models for polymer electrolyte membrane fuel cells (PEMFCs). An algorithm for nonlinear least squares constrained by partial differential equations is defined and applied to estimate effective membrane conductivity, exchange current densities and oxygen diffusion coefficients in a one-dimensional PEMFC model for transport in the principal direction of current flow. Experimental polarization curves are fitted for conventional and low current density PEMFCs. Use of adaptive mesh refinement is demonstrated to increase the computational efficiency.     

Experimental and Theoretical Investigations on the Supermolecular Structure of Isoliquiritigenin and 6-O-α-d-Maltosyl-β-cyclodextrin Inclusion Complex

Isoliquiritigenin (ILTG) possesses many pharmacological properties. However, its poor solubility and stability in water hinders its wide applications. The solubility of bioactive compounds can often be enhanced through preparation and delivery of various cyclodextrin (CD) inclusion complexes. The 6-O-α-d-maltosyl-β-CD (G₂-β-CD), as one of the newest developments of CDs, has high aqueous solubility and low toxicity, especially stable inclusion characteristics with bioactive compounds. In this work, we for the first time construct and characterize the supermolecular structure of ILTG/G₂-β-CD by scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffractometry (XRD). The solubility of ILTG in water at 25 °C rises from 0.003 to 0.717 mg/mL by the encapsulation with G₂-β-CD. Our experimental observations on the presence of the ILTG/G₂-β-CD inclusion complex are further supported by the ONIOM(our Own N-layer Integrated Orbital molecular Mechanics)-based QM/MM (Quantum Mechanics/Molecular Mechanics) calculations, typically substantiating these supermolecular characteristics, such as detailed structural assignments, preferred binding orientations, selectivity, solvent effects, interaction energies and forces of the ILTG/G₂-β-CD inclusion complex. Our results have elucidated how ILTG interacts with G₂-β-CD, demonstrating the primary host-guest interactions between ILTG and G₂-β-CD, characterized by hydrogen bonds, hydrophobic interactions, electrostatic forces, and conformational effects, are favored for the formation of the ILTG/G₂-β-CD inclusion.     

造园材料课程教学内容体系再探

造园材料课程是风景园林专业的重要基础课程,但一直以来该课程并未受到应有的重视。文章梳理了"造园材料"一词的起源及概念,明确了造园材料的分类,提出了造园材料课程教学内容体系的构建原则,简单阐述了教学实践的效果。     

三氮唑(脱氧)核苷的生产方法研究

综述了化学合成法、发酵法和酶法三种生产三氮唑(脱氧)核苷方法,指出用重组的核苷磷酸化酶进行酶法合成三氮唑核苷将是核苷类药物生产的必由之路,对核苷类衍生物药物的生产产生很大的推动作用。     

Hybrid modeling of penicillin fermentation process based on least square support vector machine

According to the problem of the pre-estimation with least square support vector machine (LSSVM) modeling is not ideal in the initial stages of penicillin fermentation process, two hybrid models are designed by utilizing the advantage of LSSVM and kinetics model. Through selecting the appropriate state variables and adopting these methods for penicillin fermentation, the mycelial concentration can be pre-estimated. Experiment results show that these hybrid modeling methods not only improve the above problem, but also have higher predicting accuracy and more powerful generalization ability than the single LSSVM method.