Yu-Shiang Wu

A Mechanically Robust and Highly Ion‐Conductive Polymer‐Blend Coating for High‐Power and Long‐Life Lithium‐Ion Battery Anodes

A mechanically robust and ion-conductive polymeric coating containing two polymers, polyethylene glycol tert-octylphenyl ether and poly(allyl amine), with four tailored functional groups is developed for graphite and graphite-Si composite anodes. The coating, acting as an artificial solid electrolyte interphase, leads to remarkable enhancement in capacity reversibility and cycling stability, as well as a high-rate performance of the studied anodes.

Hydroxyapatite synthesised from nanosized calcium carbonate via hydrothermal method

Abstract Hydroxyapatite (HAp) was synthesised using a hydrothermal method. Nanosized CaCO3 was used as the calcium source, while (NH4)2HPO4 was used as the phosphorous source. Well crystallised HAp and a small amount of β-tricalcium phosphate (β-TCP) were obtained after the hydrothermal reaction. Fourier transform infrared spectra show that under conditions of pH 6 and 250°C, the functional groups of OH− and PO43− were stronger than those under pH 10. This suggests that the powder synthesised at pH 6 has more HAp phase than that at pH 10. Scanning and transmission electron microscope images show that HAp exhibits a rod-like shape at pH 6 and 250°C. After hydrothermal reaction at pH 6 and 250°C, most products are HAp with a small amount of β-TCP synthesised as byproduct and some residual CaCO3.

CHARACTERIZATION AND PHOTOCATALYTIC ACTIVITY OF Zn2SnO4 NANOSTRUCTURES SYNTHESIZED VIA HYDROTHERMAL METHOD

Nanosized zinc stannate Zn2SnO4 (ZTO) was synthesized via a simple hydrothermal method using sodium hydroxide NaOH as a mineralizer. Hydrothermally treated at 150, 200, and 250°C for 24 h and 48 h, the X-ray diffraction (XRD) pattern showed that highly crystalline ZTO nanostructures could be formed at 200 and 250°C. Transmission electron microscopy (TEM) images showed that ZTO nanocubes were formed at 250°C, and a sheet-like structure was found at 200°C. Raman spectra revealed that ZTO had a spinel structure and there were two Raman shift peaks at approximately 668 and 535 cm-1, which were similar to the peaks of ZTO nanowires. Furthermore, the photocatalytic activity of the ZTO samples was assessed utilizing methylene blue (MB) under ultraviolet irradiation, and the UV-Visible light absorption spectra was investigated to interpret the relationship between photocatalytic properties and light absorptivity. The sheet-like ZTO nanostructures exhibited better photocatalytic activity due to their excellent lig...

Photocatalytic Analysis and Characterization of Zn2SnO4 Nanoparticles Synthesized via Hydrothermal Method with Na2CO3 Mineralizer

Zinc stannate Zn2SnO4 (ZTO) nanoparticles were synthesized via a hydrothermal process utilizing sodium carbonate (Na2CO3) as a weak basic mineralizer. The samples were hydrothermally treated at 150, 200, and 250oC for 48 h. The X-ray diffraction (XRD) patterns show that the highly-crystalline ZTO nanostructure could be formed in a well-dispersed manner for the 250°C sample at a particle size of less than 50 nm. As determined from transmission electron microscopy (TEM) results, ZTO nanoparticles are face-centered cubic single crystals agglomerated together. The Raman spectra results showed that the ZTO nanocrystals have a spinel structure. Furthermore, photocatalytic activity was tested with methylene blue (MB) by UV irradiation. The ZTO synthesized by the 2 M Na2CO3 mineralizer at 250oC demonstrated excellent photocatalytic activity. The ZTO treated three different ways had three distinct UV-Visible absorption curves, which directly influences their corresponding photocatalytic activity.

Spheroidization Modification of Artificial Graphite Applied as Anode Materials for High Rate Lithium Ion Batteries

Rate capability tests showed that artificial graphite after spheroidization treatment exhibited a higher capacity in the higher C-rate region (2~10C) at a 0.1 C rate charge and variable C-rates discharge. Artificial graphite after spheroidization treatment exhibited a higher capacity in the higher C-rate region (0.5~9 C) at the same C-rate charge and discharge. These results show that artificial graphite after spheroidization treatment has a large amount of isotropic microstructures that lithium ions can intercalate into the graphene layers from all directions via edge-plane surfaces. Therefore, the artificial graphite is more suitable than natural graphite for the anode materials of high rate batteries.

Influence of Carbon Nanotubes on the Electrochemical Properties of Lithium-Ion Battery Anode Materials

Due to the quick leap on battery technology in recent years, the application of lithium-ion battery is expanding very fast. However, related researches mostly focus on surface modification of graphite anode materials. By contrast, subjects about conductive additives are relatively rare. This research investigated the adding carbon nanotubes (CNTs) on natural graphite anode materials. Due to the poor dispersing effect of CNTs, PVA was utilized as the dispersant in the process. After coating the natural graphite with PVA, modification was carried on by adding CNTs in different ratio in order to increase the electrochemical properties as well as raise rate and cycle performance of the battery. The results show that the coating natural graphite with 3 wt% PVC and then adding 2 wt% CNTs as conductive additive could achieve 361.0 mAh/g in discharge capacity. Moreover, rate and cycle performance were greatly improved at the same time.

The Evaluation of Fire Rescue Capability from Post-Earthquake Fires in Taipei, Taiwan

This paper assesses the Taipeis fire rescue capability against post-earthquake fires (PEFs) from a hypothetical earthquake. Taiwans Shanchiao Fault was used as the trigger fault for establishing earthquake modeling assumptions. Monte Carlo simulation was used with hypocenter coordinates, the Richter magnitude scale, and earthquake focal depths as the uncertainty analysis variables for performing stochastic simulations of 100 sets of seismic event parameters. These parameters were entered into the Simple Earthquake Seismic System (SESS) and the Taiwan Earthquake Loss Estimation System (TELES) to conduct uncertainty analysis regarding PEFs. PEFs were simulated and the disaster readiness of all firefighting squads (strongholds) in Taipei was investigated to analyze the uncertainty in PEF rescues. The SESS analysis results indicate that the original risk probability was 25.26%, increasing to 45.88% with the activation of a regional mutual aid system. The original risk calculated by the TELES was 52.97%, which increased to 96.22% of the overall disaster response capacity requirements after the regional mutual aid system was launched. Although the SESS results remained below the 60% risk threshold following the launch of the regional mutual aid system, the rescue capacity was substantially increased. The TELES analysis results indicate that the regional mutual aid system can substantially increase local disaster rescue capacity, nearly satisfying all disaster resource scheduling requirements. The location, scale, and pattern of earthquakes and the resulting casualties are always uncertain. However, the results of this study verify that the 2 independently developed earthquake damage estimation systems can provide an effective reference for post-earthquake rescue scheduling assessments.

Characteristic Improvement of Carbon Coating by Furan Resin on Natural Graphite as Anode for Lithium Ion Batteries

Natural graphite and carbonaceous materials are the most promising materials as the anode for lithium ion batteries. Carbon coating on natural graphite can inhibit the insertion of lithium complex into graphite and reduce its irreversibility. This study verifies that furan resin can be used as a carbon-coating material to enhance the electrochemistry of the charging and discharging cycles. Furan resin changes into amorphous carbon after heat treatment at 1100°C. It is determined that the 40 wt.% furan resin/natural graphite combination material clearly improves the electrochemical properties by electrical cycling tests. The surface properties have been investigated by Raman spectroscopy profiles and the bulk analyzed by X-ray diffraction (XRD) measurements.

Fire Hazard Factors of Residential-Commercial Composite Buildings through Fire Hazard Cases

Although meeting the regulations of the time, early buildings are prone to fire hazards, such as damages to the fire zones, changes of floor entrances and exits, locked emergency exit doors, blocking of entrances and exits by vehicles, increased fire sources, dense population in the buildings, due to insufficient professional knowledge and technology in fire prevention. Once a fire occurs, it can result in major casualties, serious loss of social costs, as well as environmental and social issues. This study investigated 17 major fire cases occurring in residential-commercial composite buildings in the last 20 years in Taiwan. The fire hazard factors were determined based on expert review. The findings can serve as a reference for fire agencies in promoting fire prevention.

Designing a Web-Based VR Machine for Learning of Packaging and Testing Skills

This research designed and implemented an interactive learning system to support self-directed learning of microfabrication technology from both technical and functional viewpoints, along with end-user evaluation results. The current study applied virtual technology to design virtual machines with online interaction, to acquaint students with microfabrication facilities, learn how to operate machines, and practice the microfabrication process through the internet. This study incorporated the microfabrication technology courses with the developed web-based learning system.