Papers by Author: Ho Chang

Abstract: This study focused on the ultrasonic nanomachining by atomic force microscopy (AFM) to understand the phenomena of the ultrasonic nanomachining. The workpiece is an Au/Ti thin film and coated on the quartz crystal resonator (QCR). The ultrasound vibration of workpiece is carried out by used the Quartz crystal microbalance (QCM). And a normal force measurement model was built by force curve measurements in ultrasound vibration environment. The influence of different experimental parameters can be studied such as normal force and repeat number on the cutting depth and chip stacking. After the experiments, it can be found that the ultrasonic nanomachining by AFM is possessed great influence on the cutting depth.

Abstract: This paper mainly focuses in the use of an atomic force microscope, research about the nanooxidation technique of conductive diamond-like carbon thin film in the atmospheric environment. The hardness, high wear resistance and chemical stability of diamond-like carbon thin film is high, and coefficient of friction is low, it is very suitable as a mold material for nanoscale mold. However, tool can only use a diamond cutter to machine the high hardness diamond-like carbon by traditional hard machining method, and tool life is not long. To overcome this drawback, the paper proposed an atomic force microscope (AFM) as a platform, a conductive AFM probe for tool under atmospheric conditions, and imposed nanooxidation technique on conductive diamond-like carbon thin film using electroluminescent etching to carry out nanofabrication processing. During the nanofabrication process, by changing the various processing parameters, such as applied voltage, repeated nanooxidation times and probe speed, etc., in order to understand the effect of processing parameters. The experimental results show, the nanooxidation technique can be carried out nanofabrication on conductive diamond-like carbon thin film successfully. And found that applied voltage, repeated nanooxidation times and probe speed all for the groove depth on the conductive diamond-like carbon thin films have significant influence. Additionally, this study successfully created a nanopattern. Therefore, the adequate machinability of DLC coating was achieved successfully in this study, indicating a promising application in the fabrication of nanopatterns on a nanoscale.

Abstract: This study aims to deal with the preparation of membrane-electrolyte assembly (MEA) of Pt/Ru/C nanocomposite as well as connecting to a direct methanol fuel cell and using PCB process packaging to test the efficiency of the DMFC. The components assembled in DMFC are including anode flow field plates, MEA and current collector.Using PCB boards for the anode flow field plates as well as the electicity collector plates and the type of flow field plate adopts serpentine flow field. For the efficiency of DMFC, liquid motors are used to press methanol mixed solution at specific temperature into DMFC. Besides, the cathode of DMFC adopts natural-breath method with air and uses DC electronic load to activate DMFC to investigate operating voltage and further to set constant voltage to measure current to calculate the efficiency of DMFC. Initial results of I-V curve show that self-developed MEA of Pt/Ru/C nanocomposite can enhance around 0.2% current density of DMFC after being assembled like commercial MEA

Abstract: The purpose of the study is to measure the maximum static friction and dynamic friction in the actuation process of pneumatic cylinder after TiO2 nanoparticles are added to grease. The study makes an innovative design of a new measuring equipment of friction force, which can measure the friction force between the piston seal in pneumatic cylinder and the cylinder bore. The friction force of pneumatic cylinder bore directly affects the output dynamic property of pneumatic cylinder motion. Friction force measuring system can measure the change of friction force of pneumatic cylinder bore under the condition with different operating speeds, and can analyze the relationship between friction force of pneumatic cylinder and output dynamic property of pneumatic cylinder. Such a friction force measuring equipment takes pneumatic cylinder as an output of motive force to drive the measurement of pneumatic cylinder, and uses load cell and draw-line encoder to measure the friction force of pneumatic cylinder bore and the motion speed. In the experiment, the friction forces of pneumatic cylinder given with oil and without oil are measured respectively, achieving the friction force property of pneumatic cylinder bore when being lubricated by nanogrease added with nanoparticles of different weight percentages (wt.%). The experimental results show that adding TiO2 nanoparticles to grease can effectively decrease the friction force produced in the actuation process of pneumatic cylinder.

Abstract: The study explores the effects of the flame-retardant properties of nano-particles on water-based fire-retardant coatings, which include the effects on thermal stability and combustion properties. The coating used by the paper is acrylate resin (VAC), which is added with 3 basic components, including fire-retardant ammonium polyphosphate, pentaerythritol and melamine (APP-PER-MEL), to form an itumescent fire retardant (IFR). Then the fire retardent is added with magnesium hydroxide (Mg(OH)2, MH) nano-particles, multiwall carbon nanotubes (MWNT) and zinc borate (ZB) nano-powders of different concentrations, to form water-based fire-retardant coatings. By adjusting and controlling the concentration ratios of flame retardant to the 3 kinds of nano-particles with different profiles, the study analyzes the fire-retardant multiplying effect of nano-particles on water-based coatings. The nano-coatings mixed in special proportion are coated on plywood. Through thermogeavimetric analyzer (TGA) and cone calorimeter (CCT), the study inspects the thermal stability and combustion properties of water-based fire-retardant nano-coatings. The experimental results show that when the fire-retardant nano-coating composed of MH of concentration 28% and MWNT of concentration 2% is compared with the fire-retardant coating added with flame retardant only, the amount of residue can be increased by around 80% at combustion temperature 580°C. Besides, when the fire-retardant nano-coating composed of MH of weight concentration 28% and MWNT of weight concentration 2% is compared with the fire-retardant coating added with flame retardant only, the maximum heat release can be decreased by about 15%. The time required for this fire-retardant nano-coating to achieve maximum heat release is delayed by around 70 seconds when compared with other samples. Besides, the char-layered structure formed during thermal decomposition of nano-coating is more compact than the char-layered structure of water-based coating composed of the flame-retardant APP-PER-MEL components only. Therefore, nano-coatings can effectively decrease the transfer of heat and inflammable volatiles to plywood surface, and can enhance the flame retardant performance of plywood.

Abstract: This study develops a nanocomposite structure with magnetism and biocompatibility. Composite structures with magnetism can be applied for biomarkers, specific tissue cell detection and targeted drug therapy. This study adopts a chemical disposition method to prepare Fe3O4 magnetic nanoparticles with the average size of 20-25nm. The complex biocompatible chitosan-alginate membrane covers Fe3O4 magnetic nanoparticles and the thickness of the complex membrane is controlled at 50-80nm. The efficiency of the oligonucleotide (ODN) combination is increased through the high biocompatibility of this composite film. Two groups of different sequences of ODNs and a bridge ODN undergo hybridization. The results show that the intensity at which the Fe3O4 is covered by chitosan-alginate composite film conjugated with ODNs is 2300nN. Furthermore, Fe3O4 covered by complex membrane of chitosan-alginate hybridized with 30 μM ODNs to yield the optimum hybridization intensity of 4528 nN, and the average hybridization intensity of ODNs with different concentration is 3971 nN.

Abstract: This study proposes a new method—the ultrasonic vibration-assisted arc-submerged nanofluid synthesis system (VANSS). This method prepares for water-based TiO2 woodenware nano-coating and applies the nano-coating to medium density fiberboard (MDF) to measure the characteristics of the coatings on the woodenwares. For VANSS, water-based coating serves as dielectric fluid and anodes, while cathode electrodes use titanium rods (editor’s note: please check carefully and consider revising the above sentence. I’m confused by the multiple use of ‘and’ in this case). Electrodes soon vaporize under the influence of a high-temperature plasma arc and instantly condense into nanoparticles under the cool effect of low-temperature dielectric fluid to form Ti nano-coating with good suspension. Placed for two weeks, Ti nano-coating has transformed into TiO2 nano-coating. TiO2 nano-coating is applied to MDF to compare the coating with and without the addition of TiO2 nanoparticles. The results show that TiO2 nanoparticles have an average particle size of 20 nm. For the coating properties test, the results show that lightness rises from 49.7 to 69.32, increasing 39.5 % after the coating is added to the TiO2 nanoparticles. Chroma lowers from 37.1 to 33.3, decreasing 11.3 % after the coating is added to the TiO2 nanoparticles. However, hue difference is within 3 %, having little influence on vision. Adhesion enhances from 1B to 5B, increasing 4 grades when the aqueous polyurethane, AE-418, is added to the TiO2 nanoparticles; solvent resistance elevates from 46.3 % to 56.8 %, increasing 10.5 % after the coating is added to the TiO2 nanoparticles.

Abstract: The purpose of this study is testing the force of green energy lift mechanism and analyzes its result to get the key technology for green energy (saving force and energy). At first, the green energy lift mechanisms on the market are surveyed, then the mechanism are analyzed in this study. The force balance system of the mechanism is used to save force and energy. The position limitation of saving force and energy for the force balance system will be investigated. Universal testing machine is used to test the driving force by the different loads during the lift mechanism moving downward. The tested results of the driving force will be estimated. The study results show that the loads influence significantly the driving force. The angle between pulley and wire is the key factor of the driving force.

Abstract: This study adds nanopowder, such as ZnO and TiO₂, in different concentrations to water-based woodenware coating, and explores the properties of the coating on the woodenwares. After the coating has been applied to the testing materials, the thickness and lightness are measured. These values are compared to the properties of the water-based woodenware coating with nanopowder of specific concentration, such as hardness, lightness and adhesion. According to the results of the experiments, adding TiO₂ nanopowder to the AE-418 water-soluble polyurethane coating helps to increase the hardness of the coating. The amount added is positively related to the hardness of the coating; the result is the opposite with the WP-1715 water-soluble acrylic resin coating. After adding powder such as TiO₂ or ZnO to the AE-418 water-soluble polyurethane coating, the lightness of the coating becomes lower. However, powder with higher concentration leads to higher lightness. In addition, the adhesion of the coating is stronger when nanopowder of higher concentration is added.

Abstract: The paper deals with a coating CuO thin film coating on the surface of semiconductor thermoelements (Bi2Te3). In addition, the recycled external exhaust heat is used to generate electric power, further enhancing the thermoelectric conversion efficiency of the thermoelectric generator (TEG). By using electrophoresis deposition, a CuO nanofluid with high suspension stability and good dispersion is deposited on an aluminum foil at a thickness of 0.1mm. This film is conjugated with the top and base of a semiconductor thermoelements (Bi2Te3), and a thermoelectric generator is assembled in parallel with the modified thermoelectric material. Experimental results show that the CuO nanofilm coating on the surface of semiconductor thermoelements can enhance the overall heat conduction and thermoelectric conversion efficiency of thermoelectric generators by as much as 30%.