Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance （PTCR）. The fine grain of ceramic powders and base metal nickel are necessary. This paper uses re...Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance （PTCR）. The fine grain of ceramic powders and base metal nickel are necessary. This paper uses reducing hydrazine to gain submicron nickel powder whose diameter was 200-300 nm through adjusting the consumption of nucleating agent PVP properly. The submicron nickel powder could disperse well and was fit for co--fired of multilayer chip PTCR. It analyes the submicron nickel powder through x-ray Diffraction （XRD） and calculates the diameter of nickel by PDF cards. Using XRD analyses it obtains several conclusions： If the molar ratio of hydrazine hydrate and nickel sulfate is kept to be a constant, when enlarging the molar ratio of NaOH/Ni^2＋, the diameter of nickel powder would become smaller. When the temperature in the experiment raises to 70-80 ℃, nickel powder becomes smaller too. And if the molar ratio of NaOH/Ni2＋ is 4, when molar ratio of （C2H5O）2/Ni^2＋ increases, the diameter of nickel would reduce. Results from viewing the powders by optical microscope should be the fact that the electrode made by submicron nickel powder has a better formation and compactness. Furthermore, the sheet resistance testing shows that the electrode made by submicron nickel is smaller than that made by micron nickel.展开更多
Carbon fiber oxidized by KMnO4 was combined with ethylene vinyl acetate（EVA） copolymer,the obtained composite shows a fine stability of thermal cycles and nearly unchanged switching temperature under thermal（cycles...Carbon fiber oxidized by KMnO4 was combined with ethylene vinyl acetate（EVA） copolymer,the obtained composite shows a fine stability of thermal cycles and nearly unchanged switching temperature under thermal（cycles）,at the same time negative temperature coefficient（NTC） phenomenon is eliminated.Solvent-extraction method is used to examine the interaction between EVA and CF and insolublity with the gel structure were found.The crosslinking network in the gel adsorb CF intensely which makes CF disperse in EVA uniformly,orientate consistently,combine with EVA tightly and shows the elimination of NTC phenomenon.The（switching） temperature of the composite in the heating process is not identical with that of the composite in the cooling process absolutely,but the temperatures in the above two processes are consistent with the outset of melting temperature and the end of crystallization temperature respectively.展开更多
针对目前虚拟实验热触觉装置缺乏的现状,设计了一种基于PTC(Positive Temperature Coefficient)加热片的热触觉感知复现系统。该系统利用HTC VIVE的红外定位,将虚拟环境下热源的空间位置映射为现实环境下制热模块的空间位置。根据虚拟...针对目前虚拟实验热触觉装置缺乏的现状,设计了一种基于PTC(Positive Temperature Coefficient)加热片的热触觉感知复现系统。该系统利用HTC VIVE的红外定位,将虚拟环境下热源的空间位置映射为现实环境下制热模块的空间位置。根据虚拟实验中不同位置和不同温度的热源,使用两个步进电机控制热源的位置和方向,并提供4个自由度的热源定位方法;使用PID控制算法控制PTC加热片产生热风的温度,获得不同的热触觉感知。该系统以一种非接触式的触觉感知来呈现虚拟实验的热触觉,保证了热触觉产生的真实性。通过铝热反应虚拟实验,验证该系统的实用性,结果表明该系统的热触觉再现能够提高虚拟实验的真实感受,补偿触觉上缺失的热反馈。展开更多
基金Project supported by the "863" (Grant No. SQ2008AA03Z4471960)the National Natural Science Foundation of China(Grant No. 60676050)
文摘Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance （PTCR）. The fine grain of ceramic powders and base metal nickel are necessary. This paper uses reducing hydrazine to gain submicron nickel powder whose diameter was 200-300 nm through adjusting the consumption of nucleating agent PVP properly. The submicron nickel powder could disperse well and was fit for co--fired of multilayer chip PTCR. It analyes the submicron nickel powder through x-ray Diffraction （XRD） and calculates the diameter of nickel by PDF cards. Using XRD analyses it obtains several conclusions： If the molar ratio of hydrazine hydrate and nickel sulfate is kept to be a constant, when enlarging the molar ratio of NaOH/Ni^2＋, the diameter of nickel powder would become smaller. When the temperature in the experiment raises to 70-80 ℃, nickel powder becomes smaller too. And if the molar ratio of NaOH/Ni2＋ is 4, when molar ratio of （C2H5O）2/Ni^2＋ increases, the diameter of nickel would reduce. Results from viewing the powders by optical microscope should be the fact that the electrode made by submicron nickel powder has a better formation and compactness. Furthermore, the sheet resistance testing shows that the electrode made by submicron nickel is smaller than that made by micron nickel.
文摘Carbon fiber oxidized by KMnO4 was combined with ethylene vinyl acetate（EVA） copolymer,the obtained composite shows a fine stability of thermal cycles and nearly unchanged switching temperature under thermal（cycles）,at the same time negative temperature coefficient（NTC） phenomenon is eliminated.Solvent-extraction method is used to examine the interaction between EVA and CF and insolublity with the gel structure were found.The crosslinking network in the gel adsorb CF intensely which makes CF disperse in EVA uniformly,orientate consistently,combine with EVA tightly and shows the elimination of NTC phenomenon.The（switching） temperature of the composite in the heating process is not identical with that of the composite in the cooling process absolutely,but the temperatures in the above two processes are consistent with the outset of melting temperature and the end of crystallization temperature respectively.
文摘针对目前虚拟实验热触觉装置缺乏的现状,设计了一种基于PTC(Positive Temperature Coefficient)加热片的热触觉感知复现系统。该系统利用HTC VIVE的红外定位,将虚拟环境下热源的空间位置映射为现实环境下制热模块的空间位置。根据虚拟实验中不同位置和不同温度的热源,使用两个步进电机控制热源的位置和方向,并提供4个自由度的热源定位方法;使用PID控制算法控制PTC加热片产生热风的温度,获得不同的热触觉感知。该系统以一种非接触式的触觉感知来呈现虚拟实验的热触觉,保证了热触觉产生的真实性。通过铝热反应虚拟实验,验证该系统的实用性,结果表明该系统的热触觉再现能够提高虚拟实验的真实感受,补偿触觉上缺失的热反馈。
