scholarly journals Nonuniform Heating Method for Hot Embossing of Polymers with Multiscale Microstructures

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 337
Author(s):  
Chih-Yuan Chang
Keyword(s):  
Hot Embossing ◽  
Single Step ◽  
Nonuniform Heating ◽  
Process Conditions ◽  
Thermoplastic Polymer ◽  
Polymer Microstructure ◽  
Heating Method ◽  
Polymer Substrates ◽  
Flexible Fabrication

The hot embossing of polymers is one of the most popular methods for replicating high-precision structures on thermoplastic polymer substrates at the micro-/nanoscale. However, the fabrication of hybrid multiscale microstructures by using the traditional isothermal hot embossing process is challenging. Therefore, in this study, we propose a novel nonuniform heating method for the hot embossing of polymers with multiscale microstructures. In this method, a thin graphene-based heater with a nonuniform heating function, a facility that integrates the graphene-based heater and gas-assisted hot embossing, and a roll of thermoplastic film are employed. Under appropriate process conditions, multiscale polymer microstructure patterns are fabricated through a single-step hot embossing process. The quality of the multiscale microstructure patterns replicated is uniform and high. The technique has great potential for the rapid and flexible fabrication of multiscale microstructure patterns on polymer substrates.

Study on Replication of Densely Patterned, High-Depth Channels on a Polymer Substrate Using Hot Embossing Techniques

2009 ◽  
Vol 628-629 ◽  
pp. 411-416
Author(s):  
Huan Li Sun ◽  
Chong Liu ◽  
M.M. Li ◽  
Jun Sheng Liang ◽  
H.H. Chen
Keyword(s):  
Cost Effective ◽  
Hot Embossing ◽  
Experimental Results ◽  
Polymer Microstructure ◽  
Polymer Substrates ◽  
Small Channel ◽  
Cost Effective Method ◽  
Polymer Microstructures ◽  
High Depth ◽  
Replication Accuracy

Micro hot embossing process is a cost-effective method for parallel replication of polymer microstructures. To study the effect of hot embossing and demoulding parameters on the replication accuracy of the polymer microstructure, densely patterned and high-depth channels on 50mm×50mm polymer substrates were fabricated by hot embossing in this paper. Experimental results showed that the replication accuracy of the microstructure increased with the increasing of hot embossing temperature and the thickness of polymer substrates. It can be found that demoulding became more difficult when replication accuracy increased. The reason was that higher replication accuracy resulted in larger contact area between the replica and the embossing mold. The demoulding problem could be solved by rising demoulding temperature. However, overhigh demouding temperature (110°C) would lead to round corners at the edges of the ribs. Experimental results also showed that very small channel widths and depths errors (less than 1.2%) of the microstructures with 2mm thickness substrates could be achieved, when embossing and demoulding temperatures were set to 120°C and 100°C, respectively.

scholarly journals 2.45 GHz Patch Antenna Based on Thermoplastic Polymer Substrates

2018 ◽  
Author(s):  
Nurul Hanani Manab ◽  
Elfarizanis Baharudin ◽  
Fauziahanim Che Seman ◽  
Alyani Ismail
Keyword(s):  
Patch Antenna ◽  
Thermoplastic Polymer ◽  
Polymer Substrates

The Influence of the Carbonization Mechanisms on the Crystalline Quality of the Carbonization Layer for Heteroepitaxial Growth of 3C-SiC

2014 ◽  
Vol 778-780 ◽  
pp. 230-233
Author(s):  
Yukimune Watanabe ◽  
Tsuyoshi Horikawa ◽  
Kiichi Kamimura
Keyword(s):  
Diffusion Mechanism ◽  
Growth Direction ◽  
Crystalline Quality ◽  
Process Conditions ◽  
Heteroepitaxial Growth ◽  
Crystal Axis ◽  
Si Substrates ◽  
Selected Area Electron Diffraction ◽  
Better Than

The carbonized layer for a buffer layer strongly influences the crystalline quality of the 3C-SiC epitaxial films on the Si substrates. The growth mechanism of the carbonized layer strongly depended on the process conditions. The surface of silicon substrate was carbonized under the pressure of 7.8 × 10-3 Pa or 7.8 × 10-2 Pa in this research. Under the relatively low pressure of 7.8 × 10-3 Pa, the carbonized layer was grown by the epitaxial mechanism. The crystal axis of the carbonized layer grown under this pressure was confirmed to coincide with the crystal axis of the Si substrate from the results of the selected area electron diffraction (SAED) analysis. Under the relatively high pressure condition of 7.8 × 10-2 Pa, the carbonized layer was grown by the diffusion mechanism. The result of the SAED pattern and the XTEM image indicated that this layer consisted of small grainy crystals and their crystal axes inclined against the growth direction. It was confirmed that the crystalline quality of the SiC film deposited on the carbonized layer grown by the epitaxial mechanism is better than that deposited on the layer grown by the diffusion mechanism.

Single step synthesized three dimensional spindle-like nanoclusters as lithium-ion battery anodes

CrystEngComm ◽  
2018 ◽  
Vol 20 (22) ◽  
pp. 3043-3048 ◽  
Author(s):  
Lingyu Zhang ◽  
Zhigang Gao ◽  
Haiming Xie ◽  
Chungang Wang ◽  
Lu Li ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Lithium Ion Battery ◽  
Anode Materials ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Single Step ◽  
Conventional Heating ◽  
Heating Method ◽  
3D Architecture ◽  
One Step

A facile, green, mild and one-step conventional heating method was developed to synthesize monodisperse Sn-doped Fe2O3 nanoclusters with a novel spindle-like 3D architecture as anode materials for lithium-ion batteries.

Understanding Smart City Solutions in Turkish Cities From the Perspective of Sustainability

2018 ◽  
pp. 236-266
Author(s):  
H. Filiz Alkan Meshur
Keyword(s):  
Information And Communication Technologies ◽  
Smart City ◽  
Social Life ◽  
Communication Technologies ◽  
Global Scale ◽  
Single Step ◽  
Information And Communication ◽  
General Practices ◽  
Urban Problems

The purpose of this chapter is to analyze the concept of smart city and its potential solutions to correct urban problems. Smart city practices and solutions have been investigated through the lens of a sustainable perspective. As the general practices in the global scale were examined, particular focus has been directed to smart city practices in Turkey and applicable suggestions have been developed. A number of cities in Turkey rank the lowest in the list of livable cities index. Consequential to the rapidly rising population ratios, the quality of provided services declines; economic and social life in cities are adversely affected and brand images of cities are deteriorated. With the implementation of smart city practices, such problems could be corrected, and these cities could gain competitive advantage over their rivals. The key component of this smart administration is to most effectively utilize information and communication technologies during each single step of this process.

Gate Stack Engineering for High Temperature Silicon Carbide CMOS ICs

2015 ◽  
Vol 2015 (HiTEN) ◽  
pp. 000033-000036 ◽  
Author(s):  
M.H. Weng ◽  
A.D. Murphy ◽  
D.T. Clark ◽  
D.A. Smith ◽  
R.F. Thompson ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Systematic Evaluation ◽  
Process Conditions ◽  
Operating Characteristics ◽  
Gate Stack ◽  
Metal Insulator ◽  
Semiconductor Interfaces

The potential to thermally grow SiO2 on silicon carbide has resulted in it becoming the technology of choice to realise high temperature CMOS circuits. The challenge to achieve a high quality gate stack relies on engineering the metal-insulator-semiconductor interfaces to enable reliable high temperature functionality. Here we describe the effect of different process conditions for the formation of the dielectric layer on the characteristics of the resulting devices. The operating characteristics at elevated temperatures depend critically on the quality of the gate stack. Therefore a systematic evaluation of the intrinsic properties of the gate stack and data from reliability tests are needed.

scholarly journals Effect of Electron Beam Method on Processing of Titanium Technogenic Material

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 683 ◽  
Author(s):  
Katia Vutova ◽  
Vania Vassileva ◽  
Vladislava Stefanova ◽  
Dinesh Amalnerkar ◽  
Takeshi Tanaka
Keyword(s):  
Electron Beam ◽  
Removal Efficiency ◽  
Beam Power ◽  
Melting Time ◽  
Process Conditions ◽  
Technological Parameters ◽  
Electron Beam Processing ◽  
Composition Variation ◽  
High Level

This study reveals the efficiency of the electron beam processing of titanium technogenic material with a high level of impurities and the quality of the obtained metal in correlation to process parameters which are discussed. The influence of the beam power and melting time on the composition variation, morphologies, hardness of metal samples and mass losses is investigated. Based on the different technological parameters, the removal efficiency of impurities is also discussed, and the corresponding experiments are carried out in order to make a comparison. Different thermal process conditions are realized during the single-melt operation. Chemical and metallographic analyses are performed, and the results are discussed. The hardness of the titanium decreases by prolonging the time of the electron beam processing. A maximal overall removal efficiency of 99.975% is seen at 5.5 kW beam power for a 40 min melting time and the best purification of Ti (99.996%) is achieved.

scholarly journals Modelling and thermal simulation of absorber-free quasi-simultaneous laser welding of transparent plastics

2020 ◽  
Vol 64 (11) ◽  
pp. 1939-1946
Author(s):  
Nam-Phong Nguyen ◽  
Stefan Behrens ◽  
Maximilian Brosda ◽  
Alexander Olowinsky ◽  
Arnold Gillner
Keyword(s):  
Laser Wavelength ◽  
Single Step ◽  
Fibre Laser ◽  
Biotechnological Applications ◽  
Laser Transmission Welding ◽  
Emit Radiation ◽  
Radiation Sources ◽  
Plastics Processing ◽  
Plastic Components

Abstract The growing demands on the quality of plastic components and the trend towards miniaturisation are posing a great challenge on plastics processing technology. As many complex components can no longer be manufactured in a single step, joining processes such as laser transmission welding are gaining in importance. In classic laser transmission welding, the joining partners have different optical properties. The upper joining partner is transparent in the laser wavelength range, whilst the lower partner is absorbent due to the addition of absorber materials. In medical and biotechnological applications, the addition of absorber materials is often undesirable due to strict biocompatibility requirements. If, on the other hand, radiation sources are used which emit radiation in the area of the natural absorption of the plastic (λ = 1600–2000 nm), untreated transparent plastics can also be welded. In this work, a theoretical model will be presented to calculate the temperature distribution and progression during quasi-simultaneous welding using a thulium fibre laser (λ = 1940 nm). A sensitivity analysis is carried out to investigate the influence of different parameters on the heat affected zone (HAZ). The simulated HAZ is then compared with the HAZ from the experimental work.

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