CHEMICAL-IONIZATION MASS-SPECTROMETRY OF BENZOYL PEROXIDE - A RADICAL AROMATIC-SUBSTITUTION RESULTING IN BIPHENYLCARBOXYLIC ACID IN THE GAS-PHASE

A radical aromatic substitution resulting in biphenylcarboxylic acid is inferred for the decomposition of benzoyl peroxide from the chemical ionization and collision-induced dissociation mass spectra. The thermolysis of benzoyl peroxide gives rise to a benzoyloxy radical, which undergoes rapid decarboxylation and hydrogen abstraction leading to phenyl radical and benzoic acid, respectively. Attack of the resulting phenyl radical on the benzoic acid results in bipbenylcarboxylic acid. On the other hand, the phenyl radical abstracts a hydrogen atom to yield benzene, which is then subjected to the attack of a benzoyloxy radical, affording phenyl benzoate. This substitution reaction rather than the recombination of benzoyloxy and phenyl radicals is found to be responsible for the formation of phenyl benzoate under the present conditions.

甾体化合物结构活性相关性的SIMCA方法研究

本文用模式识别(PR)技术中的SIMCA法对甾类抗炎药物进行了结构活性相关性的研究。“训练集”和“测试集”分别为50个和27个甾类药物。利用模型化能力(MP)、判断能力(DP)和变化幅度权重(VW)三个因子从16维特征中选取了11维,分别对“训练集”和“测试集”进行了SIMCA法分类,平均识别率和平均预测率分别为95％和85％。通过SIMCA法所得到的参数“得分scores”与这类药物的活性相关联,对于新的8个甾类药物进行了类别的划分以及活性预报。

THE CHARACTERIZATION OF 2 COPPER PHTHALOCYANINE LANGMUIR-BLODGETT-FILMS AND THEIR GAS-SENSITIVE PROPERTIES

The monolayer and deposition behaviour of a symmetrically substituted copper tetra-4-(2, 4-di-t-amylphenoxy) phthalocyanine (tapCuPc) and an asymmetrically substituted copper [tri-4-(2, 4-di-t-amylphenoxy)-mono-4-(-2-methoxyethoxy)]phthalocyanine (AsyCuPc) were investigated. The results on monolayer behaviour and spectroscopic characterization of the LB films show that both CuPc molecules in a monolayer at the air-water interface and the LB films are stacked and inclined. The gas-sensitive properties show that the responding speed of AsyCuPc LB film is faster than that of tapCuPc LB film.

THE EFFECT OF FILM-FORMING CONDITIONS FOR TAPCUPC LANGMUIR-BLODGETT-FILMS ON MORPHOLOGY AND PROPERTIES

The dependence of morphology and properties on film-forming conditions is described for the symmetrically substituted copper tetra-4-(2, 4-di-t-amylphenoxy) phthalocyanine (tapCuPc) Langmuir-Blodgett (LB) films. The effects of LB film-forming conditions (such as the surface pressure, pH value and the concentrations of spreading solutions) on film quality were studied with the help of a UV-visible spectrophotometer and a transmission electron microscope. Transmission electron microscopy photographs of the surface morphology of tapCuPc LB films show that a smooth and homogeneous surface structure can be obtained under optimum film-forming conditions.

高聚物玻璃化转变温度和分子参数的关系 Ⅰ.高聚物链柔性与T_g的关系

本文采用晶格模型,以动力学链段长度作为统计单元大小,推导了高聚物玻璃化温度T_8和链静态刚性因子σ~2(T_8),链动态刚性因子β(T_8)以及聚合度DP等分子参数之间的关系。具体讨论了链柔性对T_8的影响。理论预测和几十种聚合物的实验数据能较好吻合,分析结果表明T_8值基本上取决于高聚物链σ(T_8)大小。

The preparation and bioactivity research of agaro-oligosaccharides

Agaro-oligosaccharides were hydrolytically obtained from agar using hydrochloric acid, citric acid, and cationic exchange resin (solid acid). The FT-IR and NMR data showed that the hydrolysate has the structure of agaro-oligomers. Orthogonal matrix method was applied to optimize the preparation conditions based on alpha-naphthylamine end-labeled HPLC analysis method. The optimal way for oligosaccharides with different degree of polymerization (DP) was achieved by using solid acid degradation, which could give high yield and avoid solution neutralization process. Agaro-oligosaccharides with high purity were consequently obtained by activated carbon column isolation. Furthermore, the antioxidant and alpha-glucosidase inhibitory activity of three fractions were also investigated. The result indicated that 8% ethanol-eluted fraction showed highest activity against alpha-glucosidase with IC50 of 8.84 mg/mL, while 25% ethanol-eluted fraction possessed excellent antioxidant ability.

Growth promotion of vegetative gametophytes of Undaria pinnatifida by blue light

Through an acclimation period of 10 days, compared to white light, the maximal net photosynthetic rates were significantly higher for gametophytes of Undaria pinnatifida cultivated under blue light (400-500 nm), and were lower under red light (600-700 nm). Chlorophyll c and the carotenoid content of gametophytes were similar under blue light and red light but were much lower under white light. The growth rate of female gametophytes under blue light was higher than that under other lights, and the growth rate of male gametophytes showed little variation with respect to blue and white light. Male and female gametophytes were mixed together to form sporophytes under white, blue and red light. After approximately 5 days, 50% gametophytes became fertile under blue and white light, but remained vegetative under red light after 10 days.

Mass culture of Undaria gametophyte clones and their use in sporeling culture

Undaria pinnatifida (Harv.) Sur. is one of the three main seaweed species under commercial cultivation in China. In the mid-1990s the annual production was about 20000 tons dry. The supply of healthy sporelings is key to the success of commercial cultivation of Undaria. Previous studies demonstrated that instead of the zoospore collection method, sporelings can be cultured through the use of gametophyte clones. This paper reports the experimental results on mass culture of clones and sporeling raising in commercial scale. Light had an obvious effect on growth of gametophyte clones. Under an irradiance of 80 mumol m(-2) s(-1) and favorable temperature of 22-25degreesC, mean daily growth rate may reach as high as 37%. Several celled gametophyte fragments were sprayed onto the palm rope frame. Gametogenesis occurred after 4-6 days. Juvenile sporeling growth experiments showed that nitrate and phosphate concentrations of 2.9 10(-4) mol 1(-1) and 1.7 10(-5) mol 1(-1) were sufficient to enable the sporelings to maintain a high daily growth rate. Sporelings can reach a length of 1 cm in a month. Since 1997, extension of the clone technique has been carried out in Shandong Province. Large-scale production of sporelings for commercial cultivation of 14 and 31 hectares in 1997 and 1998 had been conducted successfully.

Comparison of photobioreactors for cultivation of Undaria pinnatifida gametophytes

Undaria pinnatifida gametophytes were grown in 2.5 l bubble column and airlift reactor at 25 degreesC and light intensity of 40 mumol m(-2) s(-1) for 6 days. With aeration at 1 l min(-1), the airlift reactor yielded higher growth rate (0.12 mg DW ml(-1) d(-1)) than a bubble column (0.08 mg DW ml(-1) d(-1)). The advantages were related to the more homogeneous fluid dynamic characteristics of the airlift reactor.

A new method of Laminaria japonica strain selection and sporeling raising by the use of gametophyte clones

One-celled female and male gametophytes of three Laminaria japonica strains were isolated, cultured and gametophyte clones were formed. A technique combining strain selection with sporeling raising by the use of these female and male gametophyte clones was studied. Experiments on 9 different crossing combinations was conducted in November of 1997 in Qingdao, P. R. China. The main economic characteristics, frond length and fresh weight, of sporophytes of different crossing combinations were measured. F-1 sporophytes of No. 2 showed a higher fresh weight and longer length, therefore, No. 2 (Wh860 + x Lid) was selected as a good combination. Its parental female and male gametophyte clones are being mass cultured for sporeling production. By this method, the time needed for strain selection was shortened from 5-6 to 2 years. As compared with the routine method of sporeling raising by the collection of zoospores, the time of sporeling raising of this method decrease by 50%, and the production cost is also reduced by 50%. It is believed that this method will be labour and time saving and a more economic way for strain selection and sporeling raising in L. japonica cultivation industry.

Flocculation and removal of the brown tide organism, Aureococcus anophagefferens (Chrysophyceae), using clays

Previous attempts to remove the brown tide organism, Aureococcus anophagefferens, through flocculation with clays have been unsuccessful, in spite of adopting concentrations and dispersal protocols that yielded excellent cell removal efficiency (RE>90%) with other species, so a study was planned to improve cell removal. Four modifications in clay preparation and dispersal were explored: 1) varying the salinity of the clay suspension; 2) mixing of the clay-cell suspension after clay addition; 3) varying of concentration of the initial clay stock; 4) pulsed loading of the clay slurry. The effect of salinity was dependent on the clay mineral type: phosphatic clay (IMC-P2) had a higher RE than kaolinite (H-DP) when seawater was used to disperse the clay, but H-DP removed cells more efficiently when suspended in distilled water prior to application. Mixing after dispersal approximately doubled RE for both clays compared to when the slurry was layered over the culture surface. Lowering the concentration of clay stock and pulsing the clay loading increased RE, regardless of mineral type. However, this increase was more apparent for clays dispersed in seawater than in distilled water. In general, application procedures that decrease the rate of self-aggregation among the clay particles and increase the collision frequency between clay particles and A. anophagefferens achieve higher cell removal efficiency. These empirical studies demonstrated that clays might be an important control option for the brown tide organism, given the proper attention to preparation, dispersal methods, environmental impacts, and the hydrodynamic properties of the system being treated. Implications for the treatment of brown tides in the field are discussed.

Hypoxia-inducible factor 1 alpha cDNA cloning and its mRNA and protein tissue specific expression in domestic yak (Bos grunniens) from Qinghai-Tibetan plateau

Adaptation to hypoxia is regulated by hypoxia-inducible factor 1 (HIF-1), a heterodimeric transcription factor consisting of an oxygen-regulated a-subunit and a constitutively expressed beta-subunit. How animals living on Qinghai-Tibetan plateau adapt to the extreme hypoxia environment is known indistinctly. In this study, the Qinghai yak which has been living at 3000-5000 m attitude for at least two millions of years was selected as the model of high hypoxia-tolerant adaptation species. The HIF-1 alpha ORFs (open reading frames) encoding for two isoforms of HIF-1 alpha have been cloned from the brain of the domestic yak. Its expression of HIF-1 alpha was analyzed at both mRNA and protein levels in various tissues. Both its HIF-1 alpha mRNA and protein are tissue specific expression. Its HIF-1 alpha protein's high expression in the brain, lung, and kidney showed us that HIF-1 alpha protein may play an important role in the adaptation to hypoxia environment. (c) 2006 Elsevier Inc. All rights reserved.

Leptin cDNA cloning and its mRNA expression in plateau pikas (Ochotona curzoniae) from different altitudes on Qinghai-Tibet Plateau

Leptin, an adipocyte-derived hormone, plays all important role in body energy homeostasis. Plateau pika (Ochotona curzoniae), an endemic and keystone species living only at 3000-5000 in above sea level oil Qinghai-Tibet Plateau, is a typically high hypoxia and low temperature tolerant mammal with high resting metabolic rate (RMR), non-shivering thermogenesis (NST), and high ratio of oxygen utilization to cope with harsh plateau environment. To explore the molecular mechanism of ecological acclimation in plateau pika, we first cloned pika leptin cDNA and compared its mRNA expression in different altitudes (3200 and 3900 in) using real-time RTPCR (Taqman probe) technology. The full-length pika leptin cDNA was 3015 with 504 bp open-reading frame encoding the precursor peptide of 167 amino acids including 21 residues of signal peptide. Pika leptin was 70-72% homologous to that of other species and was of similarly structural characteristics with other species. The pika-specific genetic diversity in leptin sequence occurred at twenty sites. With the increase in attitude, there were larger fat store and high level of ob gene expression in plateau pika. Our results indicated that leptin is sensitive to cold and hypoxia plateau environment and may play one of important roles in pika's ecological adaptation to harsh plateau environment. (c) 2006 Elsevier Inc. All rights reserved.

工业无线网络化控制系统结构及调度问题研究

无线通信技术在工业网络化控制系统中的应用已成为当今工业领域中的研究热点。然而无线通信技术在恶劣的工业环境中通信质量严重下降，使得现有无线通信技术在工业网络化控制系统中的应用受阻。为此在不断提高和改进无线信号传输性能的同时，更要在控制系统级层面上充分考虑无线通信技术的特点，进行相关系统结构和实时调度机制等方面的改进，以达到使系统产生的通信任务在应用层上得到可靠、实时调度的目的。同时也要从无线网络技术层面上入手，解决上层下达的通信任务在数据链路层中的实时调度问题。要设计适合工业无线网络化控制系统应用特点的MAC协议来有效调度网络所有节点的信息收发，减少高层下达的通信任务在网络中的平均时延，提高吞吐量，进而保证工业无线网络化控制系统的实时性。 因此，本文从工业无线网络化控制系统中的通信任务在数据链路层和应用层上的调度角度出发，以解决、改善工业无线网络化控制系统的实时性和可靠性等性能指标为目的。对工业无线网络化控制系统的结构、应用层调度策略和优化以及数据链路层中的MAC协议进行了系统的研究。主要工作和贡献有以下几点： （1）对工业网络化控制系统的基本问题和引入无线通信技术后产生的问题进行了探讨。在定性分析了工业环境对无线通信的影响及要求的同时，又推导出了无线通信的链路预算模型，并利用Matlab对该预算模型进行了建模，计算出了在工业级噪声指数和工业要求的误码率下，IEEE802.11b和IEEE802.15.4两大主流无线通信技术的链路预算情况及具体的量化数据。 （2）提出了工业无线网络化控制系统的双频二级拓扑结构和多路径传输机制。利用了无线信道特点和路径冗余优势，在系统级上改进了目前无线通信技术在工业网络化控制系统中的应用模式，部分缓解了无线通信技术在工业恶劣环境中的实时性和可靠性问题。为工业无线网络化控制系统结构的设计做了有益的尝试。同时，首次将DS-UWB技术应用于工业网络化控制系统中，设计出了基于该结构的UWB和FF及PROFIBUS的集成方案，为该结构的快速应用提供了有效的途径。 （3）提出了极大容忍无线通信时延的调度算法(GTD)。有效解决了工业无线网络化控制系统中周期性通信任务的实时性问题,部分弥补了因无线网络时延而导致周期性通信任务超时的缺陷。并针对GTD调度算法产生的通信窗口碎片问题进行了优化处理，又提出了面向非周期信息吞吐量最大化的优化调度算法，该算法提高了非周期性通信任务的吞吐量。同时，给出了基于这两种调度算法的非线性规划模型的调度时间表求解方法。 （4）提出了根据通信任务调度时间表进行分配无竞争期的混合CAP和CFP的MAC协议（HAF-MAC）。解决了工业无线网络化控制系统上层下达的周期性通信任务和非周期性通信任务在数据链路层中的实时调度问题，并有效解决了本文提出的应用层调度算法生成的预留时间可能存在浪费的问题。同时，在理论分析了HAF-MAC协议时隙利用率的基础上，提出了基于时隙的HAF-MAC（TSHAF-MAC）协议。TSHAF-MAC协议比HAF-MAC协议提高了时隙利用率，使吞吐量和平均延时得到了进一步改善，进而提高了非周期性通信任务的实时性。最后，对这两个协议进行了仿真建模与验证，进而较系统地解决了工业无线网络化控制系统中的通信任务的实时调度问题。 （5）分别将论文中的第三章和第四章的部分研究成果,在本人博士研究阶段研发的无线智能照明控制系统这一物理实验平台上进行了一定的验证。

一类载人潜水器的改进LQG控制研究

针对一类载人潜水器(MSV,MannedSubmersibleVehicle)在动力定位中多自由度之间存在的强耦合、非线性,以及系统参数的时变特性,文章采用带遗忘因子的递推最小二乘法和平方根法对系统参数进行辨识,然后在状态空间进行多输入多输出(MIMO)线性系统的最优控制研究。仿真结果表明,该两种改进LQG控制方法对于外界扰动以及系统的参数时变具有良好的控制效果,控制精度得到提高,为实际载人潜水器控制系统的多自由度动力定位控制提供了坚实的依据。