Applied Mechanics and Materials Vol. 487

Abstract: Objective: The aim of this study was to investigate and compare the loading and unloading characteristics of various nickel-titanium (NiTi) and nickel-titanium-copper (NiTiCu) after direct electric resistance heat treatment method (Bender soarer-X equipment). Materials and Methods: Five types of commercial NiTi and NiTiCu orthodontic archwires [NiTi (W&H), NiTi (Ormco), CuNiTi (Ormco), Sentalloy (Tomy) and L&H (Tomy)] underwent heat treatment by the Bender soarer-X equipment and all samples underwent the three point bending tests to analyze their loading and unloading characteristics. Each type of wire was divided into 6 groups with 10 samples per group with one of the groups serving as non-heat treatment control group. The wire composition was analyzed by energy dispersive spectroscopy (EDS) method. Results: The results showed that the loading and unloading characteristics of W&H NiTi and Ormco NiTi after heat treatment were not significantly different from the non-heat treatment groups. But the Tomy Sentalloy, Tomy L&H and Ormco NiTiCu had significantly different results (p<0.05) after heat treatments. The factors which could affect the loading and unloading characteristics were the difference in alloy composition and the condition of heat treatment. Conclusion: Heat treatment increased the loading and unloading force of Tomy L&H and improved the shape forming ability of NiTi wire.

Abstract: This paper investigates the factors that affect the surface roughness on an Aluminium deposited wafer after reactive ion etching (RIE) using a combination of Tetrafluoromethane (CF₄) and Oxygen (O₂) gaseous. A total of four controllable process variables, with 16 sets of experiments were scrutinized using an orderly designed design of experiment (DOE). The four variables in the investigation are the composition of CF₄ gas, the composition of O₂ gas, RF power, and time. The estimate of effect calculated for the composition of CF₄ gas, the composition of O₂ gas, RF power, and time are-0.9813, -0.7488, -0.0438, and 4.7138 respectively. All factors gave negative effects except for time. This implies that the surface roughness decreases when the content of CF₄, O₂, and RF power is high. The results indicate that time is the most influential factor compared to the other three factors and is directly proportional to the surface roughness of the etched Aluminium deposited wafer.

Abstract: High power light emitting diodes is the new era of lighting due to momentous supremacy in terms of lighting efficacy over traditional lighting systems. The reliability of LED is dependent on its junction temperature. This study confers on the thermal and stress characterization of LED chip with copper cylindrical heat slug through simulation method. The simulation characterization was carried out with Ansys version 11 at ambient temperature of 25°C under natural convection condition. The LED package was powered with input powers of 0.1 W, 0.5 W and 1W .Results indicated that input power influences the junction temperature and stress of LED chip.

Abstract: Thermal management of high power LED is crucial the reliability and performance of the LED affected by the heat produced during photon emission. Heat sinks are utilized to dissipate the heat and to lower the operating junction temperature of LED. This paper demonstrates a simulation work done to evaluate the influence heat sink fin number on the junction temperature and stress of single chip LED package using Ansys version 11. The heat sink with fin number of 4 fins, 6 fins and 8 fins were used and compared. Results showed that increase in heat sink fin number significantly reduces the junction temperature of the LED package.

Abstract: Effects of specific pressure and the dual refiner of Al-5Ti-1B and Al-10RE on microstructure of the hollow 2024 aluminum alloy drive shaft prepared by squeeze casting in express locomotive were investigated in this paper. With the increasing specific pressure, the ɑ-A1 primary grains became rounder and smaller. With the specific pressure up to 120 MPa, the average grain size of the ɑ-A1 primary grains and the average equivalent roundness were 38 μm and 0.75 respectively. When the dual refiner was adopted, the average grain size of the alloy decreased obviously with a lower mass fraction of A1-5Ti-1B and a higher mass fraction of Al-10RE. However, no obvious change was detected in the average equivalent roundness. The roundness value ranged from 0.62 to 0.72. With the dual refiner of 1wt% Al-5Ti-1B and 3wt% Al-10RE, the average grain size of the alloy and the average equivalent roundness were 26 μm and 0.71 respectively.

Abstract: Gelatin and polyethylene oxide and styrene-butadiene rubber to blend with water as solvents, and add to improve adhesion surface active agent, the composition of multi-component blend to lithium iron phosphate batteries battery anode materials have the effect of adhesion. Experiments show that the multi-component water-based adhesives in lithium iron phosphate coating process good effect.

Abstract: As the population ages, dementia disease is increasingly becoming the most concerned social problems. According to the cause of dementia, it can be divided into many kinds class, among them with Alzheimer's Disease (Alzheimers diseases, AD) and Vascular Dementia (Vascular Dementia, VD) are common. Data shows it accounts for nearly 60% of total AD dementia patients, VD (20%), but only 2% of patients could get timely diagnosis and treatment, make its cognitive damage to a certain extent suppress and improve. for untimely diagnosis and treatment, most patients makes the disease development worse. In recent years, studies have shown that plasma Homocysteine,Hcy levels associated with AD. And studies show that from the power of the risk factors to the mechanism analysis, dementia disease level correlation with magnesium ions. On this basis, this study of plasma homocysteine in patients with AD,VD and magnesium ion detection results were analyzed retrospectively. Discuss their levels between the distributio relationship of patients ages in AD and VD.

Abstract: Surface integrity is widely used for evaluating the quality of machined components. It has a set of various parameters which can be grouped as: (a) topography parameters (b) mechanical parameters and (c) metallurgical state. Many factors affect surface integrity including cutting parameters, tool geometry, material properties and vibrations. We can make prediction and optimization for surface integrity by taking advantages of these factors. This paper reviews previous studies and offers a comprehensive summary of surface integrity in the following order: introduction of surface integrity, main parameters of surface integrity, factors affecting surface integrity, prediction and optimization for surface integrity.

Abstract: Gelatin and polyethylene oxide and styrene-butadiene rubber to blend with water as solvents, and add to improve adhesion surface active agent, the composition of multi-component blend to lithium iron phosphate batteries battery anode materials have the effect of adhesion. Experiments show that the multi-component water-based composite binder in lithium iron phosphate coating process good dispersion effect.

Abstract: The appropriate heat treatment process may obviously enhance the material mechanics performance, lengthens the service life of the machine parts , reduces the exploitation conditions of the material . This article uses mechanical properties test and the optical microscope research quenching and tempering comprehensive heat treatment craft is 15mm controls to thickness controlled rolling and controlled cooling (TMCP) condition tissue and the properties of the EH36 level ship plate steel influence. The result indicated that, after the heat treatment the TMCP condition ship plate steel overall performance has enhances greatly, although has the drop slightly in the intensity, but its plasticity, the low temperature impact performance all has the distinct improvement in particular.