基于DSP的磁场电源控制器软件设计

为了使兰州重离子加速器冷却储存环的磁场电源控制器及时更新输出的波形数据,以TI公司的TM320C6713芯片为中央处理器,结合FPGA逻辑编程,采用双FIFO数据缓存机制和Aitken插值算法,编写并优化了磁场电源控制器软件系统。利用数据驱动模式的编程方式提高了系统的执行效率和可维护性。同时通过对更新的波形数据做Aitken插值运算,使其大小减少为原始数据的1/1024,提高了数据的传输和存储效率。经现场测试,本软件系统运行稳定可行,达到设计要求。

稠油污染土壤的臭氧预处理研究

采用蛭石模拟土壤,研究稠油污染土壤的臭氧预处理工艺。在臭氧浓度为50mg·L-1,气体流量为0.2m3·h-1的条件下,分析了臭氧通气时间、水土比、污染土壤陈化时间和污染浓度对土壤中石油烃去除率的影响。结果表明,模拟稠油污染土壤的最佳处理条件为臭氧通气30min,水土比为0∶1,此时总石油烃降解率为40.97%,其中芳烃降解率最高为90.18%,其次是饱和烃为61.81%。此外,臭氧预处理可以促使酯类等可溶性石油烃的生成,从而提高稠油的生物可利用率。因而,臭氧预处理能够降低后续处理的负荷,是一种可行的预处理方法。

东北黑土有机磷的矿化过程研究

用室内恒温控湿培养法和埋袋法研究了不同时间序列下黑土有机磷的矿化过程.结果表明,无论是实验室培养法还是埋袋法,有机磷含量和矿化速率都逐渐下降,累积矿化率逐渐上升.培养法中,两个处理的矿化速率均在1个月时最大,分别为31.67和38.75mg·kg-1·month-1,6个月时累积矿化率和矿化速率分别为7.94%,13.26mg·kg-1·month-1;9.24%,17.99mg·kg-1·month-1.埋袋法中,5个有机物料处理的矿化速率均在1年时最大,分别为55.67、55.65、49.60、19.71和22.52mg·kg-1·month-1,3年时玉米根和小麦根处理的累积矿化率和矿化速率较高(二者3年的累积矿化率约50%,矿化速率约35mg·kg-1·month-1),而大豆根和草根的处理则较低.同时,两种研究方法均表明,有机磷初始含量影响其矿化率和矿化速率,有机磷初始含量愈高,其矿化率和矿化速率就愈高.

多环芳烃降解菌筛选及其降解特性

通过选择性富集培养,从辽河油田稠油污染土壤4号土样中,获得了能以高浓度菲(2000 mg·L-1)为唯一碳源和能源快速生长的优势菌系和优良菌株ZL5.16S rDNA核苷酸序列分析表明,ZL5菌株归类于鞘氨醇单胞菌属.分得的菌系和菌株有较强的降解菲能力,120 h混合菌系降解了投加菲的95.28％,菌株降解了69.24％,但它们对芘的降解能力均较低.外加碳源葡萄糖可提高菌系和菌株的菲、芘降解能力,加量多,提高幅度大,但超过一定量,降解速率开始下降,表现出抑制效应.所以,应用时需控制适宜的浓度.

河北省康保县景观变化研究

利用1999年TM5和2003年的SPOT5遥感影像辅助GIS技术对河北省康保县土地利用景观变化进行了系统研究,并用Logistic逐步回归对驱动因素进行分析;利用Kappa指数对分类结果进行精度评价.结果表明,1999和2003年分类结果的Kappa指数分别为86.72%和89.76%.康保县的旱地大面积减少,但仍为景观基质.菜地、人工草地、有林地面积和未成林造林地明显增加,主要由旱地、天然草地和改良草地转化而来.菜地、人工草地的变化速率增加最快,研究区的景观格局破碎化程度加剧.其景观变化主要是退耕政策实施的结果,坡向因素为主要退耕驱动因素,而直接的驱动因素是由坡向决定的水热条件和肥力因素.

利用边缘检测对高分辨率影像中建筑物的提取研究

遥感作为一种探测技术,越来越广泛地运用到城市建设等应用研究领域中。近年来,高分辨率遥感影像的应用推动了城市遥感进一步向定量化方向发展,同时,也大大增加了数据处理的工作量。如何从海量的遥感数据中筛选出有价值的信息一直是遥感影像处理工作最需要解决的难题。将尝试使用Sobel算子与数学形态学相结合的方法,利用2001年阜新市区的QuickBrid多光谱影像,探索一种高分辨率多光谱影像建筑物的提取方法。

气候变化对森林演替的影响

森林演替是森林生态动力源驱动下森林再生的生态学过程 ,自 2 0世纪初建立群落演替理论以来 ,演替研究成为生态学研究中的热点 .客观准确地认识森林演替规律 ,研究森林演替动力学机理及其模型 ,是科学管理森林生态系统的需要 ;对于天然林保护工程与森林植被的恢复重建 ,具有重要的理论与实际意义 .干扰是森林循环的驱动力 ,导致森林生态系统时空异质性 ,是更新格局和生态学过程的主要影响因素 .它可改变资源的有效性 ,干扰导致的林隙是森林循环的起点 .回顾了目前演替研究的几种方法 ,即马尔科夫模型、林窗模型 (GAP)、陆地生物圈模型 (BIOME)和非线性演替模式 .介绍了气候变化对森林演替的影响 ;并在已有成果的基础上 ,提出了目前研究存在的问题及未来的发展方向 .

Influence of the deposition energy on the composition and thermal cycling behavior of La-2(Zr0.7Ce0.3)(2)O-7 coatings

Lanthanum-zirconium-cerium composite oxide (La-2(Zr0.7Ce0.3)(2)O-7, LZ7C3) coatings were prepared under different conditions by electron beam-physical vapor deposition (EB-PVD). The composition, crystal structure, surface and cross-sectional morphologies, cyclic oxidation behavior of these coatings were studied. Elemental analysis indicates that the coating composition has partially deviated from the stoichiometry of the ingot, and the existence of excess La2O3 is also observed.

The effect of Co-60 gamma-rays on the crystal structure, melting and crystallization behavior of poly(butylene succinate)

The results obtained for poly(butylene succinate) (PBS) after Co-60 gamma-ray irradiation, studied by wide-angle X-ray diffraction (WAXD), differential scanning calorimeter (DSC) and polarizing optical microscopy (POM), revealed that the degree of crystallinity, melting temperature and enthalpy decreased with increasing irradiation dose, but that the crystal structure of PBS did not vary when compared to non-irradiated PBS. By using Scherrer equation, small changes occurred in the crystal sizes of L-020, L-110 and L-111. The spherulitic morphology of PBS was strongly dependent on irradiation dose and changed significantly at higher irradiation dosages. The crystallization kinetics of PBS indicated that the Avrami exponent (n) for irradiated PBS was reduced to 2.3, when compared to non-irradiated PBS (3.3).

Preparation and characterization of poly(ethyl acrylate)/bentonite nanocomposites by in situ emulsion polymerization

Transparent poly(ethyl acrylate) (PEA)/bentonite nanocomposites containing intercalated-exfoliated combinatory structures of clay were synthesized by in situ emulsion polymerizations in aqueous dispersions containing bentonite. The samples for characterization were prepared through direct-forming films of the resulting emulsions without coagulation and separation. An examination with X-ray diffraction and transmission electron microscopy showed that intercalated and exfoliated structures of clay coexisted in the PEA/bentonite nanocomposites. The measurements of mechanical properties showed that PEA properties were greatly improved, with the tensile strength and modulus increasing from 0.65 and 0.24 to 11.16 and 88.41 MPa, respectively. Dynamic mechanical analysis revealed a very marked improvement of the storage modulus above the glass-transition temperature. In addition, because of the uniform dispersion of silicate layers in the PEA matrix, the barrier properties of the materials were dramatically improved. The permeability coefficient of water vapor decreased from 30.8 x 10(-6) to 8.3 x 10(-6) g cm/cm(2)s cmHg. (C) 2002 Wiley Periodicals, Inc.