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直接转化法合成大尺寸纯相多晶金刚石 被引量:3
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作者 王海阔 张相法 +5 位作者 位星 王永凯 任瑛 赵海军 卢灿华 刘乾坤 《金刚石与磨料磨具工程》 CAS 北大核心 2018年第1期1-6,共6页
在不同热力学条件下,以不同碳源为初始材料,采用直接转化法合成不同晶粒尺寸、不同颜色的纯相多晶金刚石块体(φ6mm×6mm),并用X射线衍射、Raman光谱及扫描电镜等方法检测验证。采用维氏压痕法测得纳米结构的黄色透明样品硬度为130~... 在不同热力学条件下,以不同碳源为初始材料,采用直接转化法合成不同晶粒尺寸、不同颜色的纯相多晶金刚石块体(φ6mm×6mm),并用X射线衍射、Raman光谱及扫描电镜等方法检测验证。采用维氏压痕法测得纳米结构的黄色透明样品硬度为130~270GPa(加载3N)。对黄色透明样品进行砂轮对磨实验,其磨耗比达1.658×10~6,约为现在市场上主流钴基石油用金刚石复合片的25倍。差热分析表明:黄色透明样品的热稳定性与克拉级单晶金刚石基本持平;以纳米结构多晶金刚石与金刚石大单晶对磨,测定其磨耗比为2.5,表现出比金刚石大单晶更优越的耐磨性。 展开更多
关键词 纳米结构多晶金刚石 超高压烧结 直接相变
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六方氮化硼直接转化合成多晶立方氮化硼的研究 被引量:2
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作者 王永凯 位星 +4 位作者 王大鹏 魏朝阳 刘红伟 鲁翠莲 张相法 《金刚石与磨料磨具工程》 CAS 北大核心 2021年第3期19-22,共4页
以六方氮化硼为初始材料,采用直接转化法在9~15 GPa、1500~2100℃的条件下合成多晶立方氮化硼。采用X射线衍射仪、扫描电子显微镜、维氏硬度计,对多晶立方氮化硼块材的微观结构和力学性能进行表征。结果表明:在合适的温度、压力条件下,... 以六方氮化硼为初始材料,采用直接转化法在9~15 GPa、1500~2100℃的条件下合成多晶立方氮化硼。采用X射线衍射仪、扫描电子显微镜、维氏硬度计,对多晶立方氮化硼块材的微观结构和力学性能进行表征。结果表明:在合适的温度、压力条件下,六方氮化硼可转化为纯相多晶立方氮化硼,其晶粒尺寸最小约为70 nm,最大可达10μm以上;在温度相同条件下,多晶立方氮化硼块材的晶粒尺寸随着合成压力的升高而减小,硬度随着合成压力的升高而增大,最高硬度可达64.45 GPa。 展开更多
关键词 六方氮化硼 多晶立方氮化硼 高温高压 直接相变
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Formation of crystalline particles from phase change emulsion: Influence of different parameters 被引量:1
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作者 Javed Iqbal Zulfiqar Ali +4 位作者 Murid Hussain Rizwan Sheikh Khaliq Majeed Asad Ullah Khan Joachim Ulrich 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第7期929-936,共8页
Solidification or crystallization of phase change emulsion in the form of fine emulsion drops in a direct contact coolant at temperatures below their freezing point was studied. This work is mainly focused on the size... Solidification or crystallization of phase change emulsion in the form of fine emulsion drops in a direct contact coolant at temperatures below their freezing point was studied. This work is mainly focused on the size and shape of the generated partides from phase change emulsified fats. Size of the particles is the major or key factor being considered during their formation, however, other factors that govern the particle size and shape were also observed. The operating parameters of the process were optimized in order to obtain particles of smaller size ranges in the window of current operating conditions. The crystallization of complex emulsion maffices is very difficult to control in the bulk at desired requirement. Hence, the emulsion drop to particle formation has advan- tage in comparison with the bulk solidification or crystallization. The main objective of this work is to achieve spherical emulsion particles in a direct contact cooling system. Parameters like: stat)ility, characterization, viscos- ity, and the effect of different energy inputs were examined. Moreover, the effects of the capillary size, interracial tension, temperature of the emulsion on the particle size were also monitrored. 展开更多
关键词 EmulsionParticle formationSizePhase changeInterracial tension
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Analysis of the effect of HCV resistance-associated substitutions on the short-term efficacy of DAA after single administration in three phase Ib clinical trials
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作者 Jing Zhou Hong Zhang +3 位作者 Xiaojiao Li Xiangshi Song Mengmeng Zhang Yanhua Ding 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2021年第2期133-145,共13页
As crucial factors in hepatitis C virus(HCV)management,resistance-associated substitutions(RASs)are associated with the treatment outcome of some direct-acting antiviral(DAA)-based regimens.In this study,we mainly ana... As crucial factors in hepatitis C virus(HCV)management,resistance-associated substitutions(RASs)are associated with the treatment outcome of some direct-acting antiviral(DAA)-based regimens.In this study,we mainly analyzed the impact of baseline Y93 H or Y93 Y/H on the short-term efficacy after single administration of NS5 A inhibitors in three phaseⅠb clinical trials(yimitasvir phosphate,KW-136 and fopitasvir),and analyzed the prevalence of baseline RASs and treatment-emergent RASs.A total of 94 treatment-naive HCV genotype(GT)-1 b(n=63)and GT-2 a(n=31)Chinese patients were enrolled in three phase lb clinical trials.We investigated RASs in 77 patients with next generation or Sanger sequencing.In the 7-day trial of yimitasvir phosphate,the mean maximum HCV RNA decrease of patients with baseline Y93 H or Y93 Y/H was lower than that of patients without the mutation in the 30 mg and 200 mg cohorts(0.83 vs.2.45 log10 IU/mL and 1.92 vs.2.63 log10 IU/mL).In the3-day trial of KW-136,the mean maximum HCV RNA decrease in patients with baseline Y93 H or Y93 Y/H was lower than that of patients without the mutation in the 30,60 and 120 mg cohorts(1.58 vs.2.89 log10 IU/mL,3.16 vs.4.09 log10 IU/mL and3.00 vs.5.04 log10 IU/mL,respectively).In the 3-day trial of fopitasvir,only 30 mg group had baseline Y93 H or Y93 Y/H,and the average maximum HCV RNA decrease of patients with baseline Y93 H or Y93 Y/H was lower than that of patients without the mutation(1.45 vs.3.59 log10 IU/mL).In the three trials,baseline RASs were observed in 54 patients(70.1%;54/77).The most prevalent baseline RASs were Y93 H and Y93 Y/H(18.2%;14/77),followed by L3 IM(16.9%;13/77).The most common RASs after single administration of DAA were Y93 H and Y93 Y/H.Our data could provide reference for future clinical treatment and clinical trial. 展开更多
关键词 Direct acting antiviral agents Resistance-associated substitutions HCV sequencing Genotype 1b and 2a HCV NS5A inhibitors
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