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Lou Z.-F.,Key Laboratory for Precision and Non Traditional Machining of Ministry of Education | Wang L.-D.,Key Laboratory for Precision and Non Traditional Machining of Ministry of Education | Wang L.-D.,Key Laboratory for Micro Nano Technology and System of Liaoning Province | Wang X.-D.,Key Laboratory for Precision and Non Traditional Machining of Ministry of Education | Ma Y.,Key Laboratory for Precision and Non Traditional Machining of Ministry of Education
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2011

The slippage between discs and rail is one of important factors for the measurement accuracy of an involute. However, control of frictions effectively can modify the slippage of discs. In the paper, frictions between discs and rail are analyzed respectively when a cord and a belt are used to drive the discs to roll. According to the analysis and experiment, it shows that if measuring forces are 0.7 N and 0.2 N and the base discs is drived by the cord and belt, frictions are 0.02 N and 0.07 N respectively, for the base disc clockwise rolled; where the effect of the slippages of based discs on the involute measurement can be ignored. Moreover, the slippage can also be reduced by increasing the weight of base disc groups, and measurement difference of involute is 0.06 μm when the rolling directions of the base discs are different. Source


Xiao N.,Dalian University of Technology | Ling Z.,Dalian University of Technology | Wang L.-P.,Dalian University of Technology | Zhou Y.,Dalian University of Technology | And 2 more authors.
Xinxing Tan Cailiao/New Carbon Materials | Year: 2010

T-type zeolite/carbon foam composites with a hierarchical structure were prepared by carbonizing polyurethane foam impregnated with a mixture of polyamic acid and T-type zeolite. The carbonization was conducted at 900°C in flowing nitrogen. The as-prepared composites were examined using SEM, XRD and N2 adsorption techniques. It has been found that the foam-like monolith consists of open cells with an average size of ca. 500μm, and T-type zeolites are anchored on the cell walls of the foam with their structure remaining unchanged even after heat treatment at 900°C. The zeolite/CF composites with a BET surface area of 328 m2/g are microporous, and have a narrow pore size distribution centered at 0.45 nm. Source


Zhou Y.,Dalian University of Technology | Song X.-N.,Dalian University of Technology | Shu C.,Dalian University of Technology | Qiu J.-S.,Dalian University of Technology | Qiu J.-S.,Key Laboratory for Micro Nano Technology and System of Liaoning Province
Xinxing Tan Cailiao/New Carbon Materials | Year: 2011

Mesoporous carbons (MCs) were made from coal pitch derived from coal liquefaction residue with silica nanoparticles as template and CO2 as activation agent. The microstructure and electrochemical properties of the MCs were investigated with TEM, N2 adsorption, an electrochemical workstation and a Land battery test system. Results show that the specific surface area increases with activation time at 900°C under a CO2 flow rate of 100 mL·min-1. The specific surface area of MC activated for 150 min is 1360 m2·g-1 while that of the un-activated one is 722 m2·g-1. The specific capacitance of the MC activated for 150 min is 135 F·g-1 at a current density of 1000 mA·g-1 and the decrease in its specific capacitance is 7% after being charged and discharged 10000 times. Source


Le G.,Dalian University of Technology | Gao J.,Key Laboratory for Micro Nano Technology and System of Liaoning Province | Chu J.K.,Dalian University of Technology
Key Engineering Materials | Year: 2011

The methods of on-chip integrated testing have a wide application with the development of the study for MEMS materials properties measurement in microscale. A novel on-chip integrated micro-tensile testing system is designed through system-level simulation based on macromodels to measure the fracture strength and fatigue mechanical properties of polysilicon thin films. The structure of testing instrument consists of V-beam electrothermal actuator, differential capacitance sensor, supporting spring and specimen. The capacitance signal is sensed and controlled by a second sigma-delta modulator circuit. The analytic macromodel of polysilicon thin film specimen considering geometric nonlinearity and the numerical reduced-order model of V-beam electrothermal actuator based on Krylov subspace projection are created separately and described in the MAST hardware language. The mechanical structure dimension size and circuit components parameters are determined and optimized according to system-level simulation. The computing result has shown that the self-build macromodels and the on-chip integrated test system are efficient and reliable. © (2011) Trans Tech Publications. Source


Wang L.-P.,Dalian University of Technology | Zhou Y.,Dalian University of Technology | Qiu J.-S.,Dalian University of Technology | Qiu J.-S.,Key Laboratory for Micro Nano Technology and System of Liaoning Province
Xinxing Tan Cailiao/New Carbon Materials | Year: 2011

Asphaltene-based ordered mesoporous carbon (OMC) was oxidized with 5 mol/L nitric acid at 40-100°C. The influence of nitric acid oxidation treatment on its textural properties and electrochemical performance as a supercapacitor electrode material was investigated and the ionic transport behavior in relation to surface chemical structure was discussed. The pore structures and electrochemical performance were examined using XRD, nitrogen adsorption and an electrochemical workstation. Results indicate that electrochemical performance can be improved with nitric acid treatment under mild conditions. The regular mesostructure can be retained, and the surface areas and pore volumes vary slightly when oxidation temperature is below 60°C. A capacitor assembled with the OMC sample oxidized at 60°C exhibits excellent electric double layer behavior, improved frequency response characteristics and a fast charge-discharge rate with a time constant of 6 s. The gravimetric specific capacitance and energy density of OMC oxidized at 60°C are 138 F·g-1 and 3.9 Wh·kg-1 respectively at a scanning rate of 5 mV·s-1. These values are respectively 57% and 63% greater than for the un-treated one. Source

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