988 resultados para alkaline pH


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PEO/PH共混体系的组份之间存在着氢键的相互作用,从偏光显微镜观察及熔点下降法测定,PEO/PH共混体系是相容体系,且PEO是在非晶区与PH相容,PH分子链不进入到PEO的晶格中,不引起晶胞参数的改变。对PEO/PH共混体系的等温结晶动力学研究表明,随共混体系中非晶组份PH含量的增加,体系的结晶生长方式由盘状生长转化为原纤状生长,成核方式由方式I(Kg=Kg(I)=4b. σσeTm/ΔHf.K)转化为方式II(Kg=Kg(Ii)=2b. σσeTm/ΔHf.K)析叠链表面自由能(σe)逐渐增大,体系的平衡溶点降低。在PEO/PH共混体系非等温结晶动力学的研究中,DSC实验表明,在常冷却速率下,PEO/PH共混体系符合Avrami方程所揭示的规律,为更好地反映非等温结晶特点,从Avrami方程和Ozawa方程出发,导出一个新的基本方程,根据这个方程,获得了描述非等温结晶过程的一些基本参数,在一定冷却速率下,随非晶组份PH含量的增加,东混体系的结晶速率降低;对于同一组成,冷却速率越大,体系结晶速率越快。WAXD和SAXS分析表明,随非晶组份PH含量的增加,PEO/PH共混体系的结晶度降低,长周期增大,过渡层厚略有变化,但变化很小。进一步表明,过渡层基本上是PEO的非晶相的贡献,PH不进入到PEO的晶格中,PEO是在非晶区与PH相容。

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于2010-11-17批量导入

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于2010-11-23批量导入

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This paper introduced a long-term ambulatory intragastric pH monitoring system, which is designed for prolonged ambulatory studies of Gastroesophageal Reflux Diseases. The whole system is composed of the gastric catheter with two pH sensors, a small data logger (Microdatalog), and a notebook PC. In this paper, the design of monitoring system hardware and software are described in detail. Clinical applications reveal good results.

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