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This paper investigates the accuracy of different design equations given in design specifications and literatures in determining the block shear strength of the lean duplex stainless steel fillet welded connections with base metal fracture. It points out the problem inherent in the block shear provision specified in the North American cold-formed design specification, which does not consider shear strain hardening. The previous test results have found that full shear strain hardening can be assumed for the carbon steel and ferritic stainless steel welded connections, but not applicable to the thin-walled lean duplex stainless steel welded connections with a higher ratio of the tensile strength to yield stress. Based on the results of finite element analysis including ductile damage simulation, this study reveals that the block shear strength of the lean duplex stainless steel specimens can be determined accurately using the mean between the shear yield stress and the shear ultimate stress. This paper also investigates the effect of stress triaxiality incorporated in the block shear equations found in the literature through comparative analysis with the bolted connection. The effect is shown to be negligible for the thin-walled lean duplex stainless steel welded connection, although higher stress triaxiality is developed in welded connection than in bolted connection. This paper recommends a block shear equation assuming the normal tensile stress in the net area in conjunction with partial shear strain hardening. The recommended equation was found to be more accurate than other equations for determining the block shear strength of the thin-walled lean duplex stainless steel welded connections.

The debris from exploded buildings can ricochet after colliding with the ground, thus increasing the debris travel distance and danger from any associated impacts or collisions. To reduce this danger, the travel distance of ricocheted debris must be accurately predicted. This study analyzed the change in the travel distance of ricocheted concrete debris relative to changes in the properties of a sand medium. Direct shear tests were conducted to measure the change in internal friction angle as a function of temperature and water content of the sand. Finite element analysis (FEA) was then applied to these variables to predict the speed and angle of the debris after ricochet. The FEA results were compared with results of low-speed ricochet experiments, which employed variable temperature and water content. The travel distance of the debris was calculated using MATLAB, via trajectory equations considering the drag coefficient. As the internal friction angle decreased, the shear stress decreased, leading to deeper penetration of the debris into the sand. As the loss of kinetic energy increased, the velocity and travel distance of the ricocheted debris decreased. Changes in the ricochet velocity and travel distance of the debris, according to changes in the internal friction angle, indicated that the debris was affected by the environment.

We have investigated the effect of the Sr-substitution for Ba on the superconductivity in Yb0.6Ca0.4Ba2-ySryCu3O6 without Ochain forming the so-called Cu(1)O chain in the blocking layer. It has been found that Tc increases with increasing y even though no holes are doped through the Sr2+-substitution for Ba2+. The increase in Tc is because holes doped by the Ca-substitution for Yb are more likely supplied to the superconducting Cu(2)O2 plane than the blocking layer of Cu(1) owing to the contraction of the Cu(2)O2 plane through the substitution of smaller Sr2+ for larger Ba2+. The highest Tconset = 73 K observed for y(Sr) = 0.6 is greatly higher than the previous record of Tconset = 50 K in (RE,Ca)Ba2Cu3O6 (RE: rare-earth element). The reason why it is lower than ∼90 K for REBa2Cu3O7 is the low hole-concentration in the Cu(2)O2 plane.

In this study, pristine carbon nanotubes (CNTs) and the CNTs functionalized through heat treatment were fabricated, and their hydrogen (H2) gas sensing characteristics were evaluated at room temperature. Pristine CNTs exhibited relatively low reactivity toward H2 gas, whereas functionalized CNTs demonstrated linear electrical response characteristics with an increase in the gas concentration due to the presence of functional groups (such as COOH and OH) on the CNT surface, which reduced the activation energy for the adsorption of H2 molecules and provided additional reactive sites. Thus, functionalized CNTs can be potentially utilized in various fields because their operation does not require high-temperature environments (unlike the currently used metal oxide-based H2 sensors), while the power consumption and explosion risks of these materials are easily reduced through a simple heat treatment process.

Germ cell tumours (GCTs) are one of the most threatening malignancies in young men and women. Although several reports have suggested the importance of OCT4 in human GCTs, its role has not been clearly investigated on a molecular level. In this study, we revealed GCT-specific direct transcriptional target genes of OCT4. Conditional knockdown of OCT4 in GCT cell lines reduced cell proliferation by affecting both cell cycle and death. Knockdown of OCT4 also reduced stemness of GCTs, as assessed by the expression of other stemness factors, alkaline phosphatase staining, and tumour sphere formation ability. Analysis of whole mRNA expression patterns among GCT cells harbouring endogenous, depleted, and rescued OCT4 revealed 1133 OCT4 target genes in GCT. Combined analysis of both the chromatin binding signature of OCT4 and the genes whose expression levels were changed by OCT4 revealed 258 direct target genes of OCT4 in GCTs. In a similar way, 594 direct target genes in normal embryonic stem cells (ESCs) were identified. Among these two sets of OCT4 direct target genes, 38 genes were common between GCTs and ESCs, most of which were related to regulation of pluripotency, and 220 genes were specific to GCTs, most of which were related to focal adhesion and extracellular matrix organisation. These results provide a molecular basis for how OCT4 regulates GCT stemness and will aid our understanding of the role of OCT4 in other cancers.

Recently, in order to overcome the key shortcoming in Hamilton’s principle, the extended framework of Hamilton’s principle was formulated. This new variational framework provides a sound base to develop novel temporal finite element methods with the proper use of initial conditions to the strong form. As its initial and practical application in structural dynamic analysis, this paper presents a quadratic temporal finite element method for linear elastic multi-degrees-of-freedom systems. Numerical features of the developed method are analytically and numerically investigated with comparison to the currently dominant method; the results highlight the improved performance of the proposed method.

Wearable sensors for tracking human body motion are being increasingly applied in medical systems and are considered important components of human–machine interfaces. This study proposes a flexible sandwich-like capacitive pressure sensor that consists of carbon nanotube–polydimethylsiloxane (CNT–PDMS) composite electrodes and a porous polymer dielectric layer. CNT yarn and polymer materials help fabricate a pressure sensor without complex patterns, easily and quickly. The dielectric layer is made of a porous polymer to improve the sensor sensitivity. The high porosity of the dielectric layer increases its deformation under pressure and enhances the sensitivity (to approximately 5.6 kPa−1 (%)) even under low pressures ( Owing to the high porosity of the dielectric layer and flexibility of the CNT yarn, the capacitive pressure sensor proposed in this study exhibits good performance in detecting even a slight change in stimulus. The proposed pressure sensor can be applied in wearable applications such as human-friendly interfaces and sensitive electronic skins.

Internal short circuit of a lithium polymer battery (4.6 Ah capacity and 4.30 V charging voltage) with a ceramic-coated separator has been investigated by infrared measurement during nail penetration. The surface temperatures at nail penetration area and battery body were simultaneously measured by infrared camera and, as a result, three different failure modes have been proposed. The battery with 100% of SOC experiences thermal runaway phenomenon by means of the second internal short circuit. The batteries with low SOC (0% and 50% of SOC) were also investigated to identify the phenomena occurred in SOC 100% battery (the second internal short circuit), but neither fire nor explosion in the battery with low SOC was observed. The analysis of burr status after nail penetration demonstrates that it is quite important factor related to the failure modes. The results of this study can be applied to the design of safe battery.

Summary Objectives Maximal extrathyroidal extension (ETE) is known to be an important prognostic factor in papillary thyroid carcinoma (PTC). However, the significance of minimal ETE is controversial. The aim of this study was to investigate the clinicopathologic characteristics and prognostic significance of minimal vs maximal ETE in PTC. Materials and methods A group of 967 patients who underwent thyroidectomy for PTC in a tertiary hospital between January 2000 and December 2011 were studied retrospectively. Patients were classified into three groups: absence of ETE, and minimal and maximal ETE. The minimal ETE group was further categorized into two subgroups according to invasion of strap muscles or no invasion (STI+ and STI−). Results Gender did not differ between the three groups of patients. The mean age of the patients with maximal ETE was significantly higher than in those belonging to the other groups. Tumor size, bilaterality, lymph node metastasis and stage increased significantly according to the degree of ETE. Recurrence and survival rates did not differ between the absence and minimal ETE groups, or between the STI− and STI+ subgroups of minimal ETE. However, the maximal ETE group had significantly higher recurrence and lower survival rates than the other groups (P Conclusion Maximal ETE is a significant factor for poor prognosis. However, minimal ETE is not associated with increased recurrence or decreased survival in patients with PTC.

Si-Ti-Ni alloy (STN) is a promising active material for lithium ion batteries with high coulombic efficiency and stable cycleability since inactive matrix plays an important role in buffer action against large volume changes of Si during charge/discharge reactions. However, there still remain several challenges to apply to electric vehicles due to capacity fading and unstable cycle performances at high current density. In this study, to improve the properties of STN, we modified the surface of STN with poly(3,4-ethylenedioxythiophene) (PEDOT) by in-situ polymerization. The modified STN provides many advantages including stable cycleability, low charge transfer resistance, strong adhesion between active materials and active material and current collector, etc. Electrochemical performances are significantly improved after modification; especially under high current density conditions.

The areal capacity ratio of negative to positive electrodes (N/P ratio) is the most important factor to design the lithium ion batteries with high performance in the consideration of balanced electrochemical reactions. In this study, the effect of N/P ratio (1.10, 1.20, and 1.30) on electrochemical properties has been investigated with a lithium polymer battery with PVdF-coated separator and 1.40 Ah of capacity. The N/P ratio is controlled by adjusting the anode thickness with a fixed anode density. The cell with an N/P ratio higher than 1.10 effectively suppresses the lithium plating at the 0.85C-rate charging at 25 °C and the cell with 1.20 of N/P ratio shows the enhanced cycle performance in comparison with other cells. Among the cells with differently designed N/P ratios, significant difference was not observed in the aging test with fully charged batteries at 25 and 45 °C. The effect of N/P ratio on electrochemical properties of lithium batteries can help to design the safe full cell without lithium plating.

The objective of this study is to develop a new constitutive model for cyclic response of metals with much broader applicability. Accordingly, a two-surface damage thermoplasticity model is proposed to understand inelastic behavior and to evaluate a potential damaged state of the metals. This model, which derived from small strain theory, is formulated through a thermodynamic approach to damage mechanics based on entropy production. A simple shear problem was utilized to examine several effects of this model, such as fatigue by cyclic loading and temperature, and to allow for the thermal effects on metals. Following this, the proposed cyclic damage model is implemented as a user subroutine in the finite element software ABAQUS. Finally, numerical results of energy dissipation devices are compared with experimental data for validity of this model.

The degradation of cathode materials due to the so-called ‘NiO dissolution’ problem, is one of the most critical issues restricting the long-term operation of molten carbonate fuel cells (MCFCs). To overcome this problem, a modified NiO powder is prepared by the annealing of a pre-mixed powder consisting of Ni powder and Co 3 O 4 nano-particles ( n -Co 3 O 4 ) at 650 °C. Annealing above 300 °C plays an important role in converting the physically bound mixed oxide system to a chemically bound system and, therefore, the separation of n -Co 3 O 4 from Ni is prevented. This modification leads to the formation of a Ni 0.9 Co 0.1 O solid solution, and the lithiated Ni 0.9 Co 0.1 O has a core–shell structure that consists of different Li contents. Whereas the core phase has a low concentration of lithium, the outer layer is a highly lithiated phase. Since the highly lithiated outer phase, acting as a barrier, minimizes the dissolution of NiO, the modified cathode demonstrates good electrochemical properties and chemical stability under actual operating conditions. This study can provide an effective way to mass produce MCFC cathode materials.

We have successfully synthesized a new superconductor EuSr 2 Cu 2 Ta 1− x Sn x O 8− y of the so-called Ta-1212 system, where Ta is substituted for Cu(1) in the Y-123 type structure and holes are doped into the CuO 2 plane through the partial substitution of Sn 4+ for Ta 5+ . The superconducting transition temperature, T c , is about 40 K at x = 0.2. This is the first superconductor in the Ta-1212 system.

LiMn 1.5 Ni 0.5 O 4 materials coated with AlPO 4 are prepared by a sol–gel method with citric acid to improve their electrochemical performance; the physical and electrochemical properties are characterized by various analytical techniques. The coated AlPO 4 layer completely covers the surfaces of the LiMn 1.5 Ni 0.5 O 4 particles and the thickness of the coated layer is ∼15 nm. 1 wt.% AlPO 4 -coated LiMn 1.5 Ni 0.5 O 4 has much lower surface and charge-transfer resistances and shows a higher lithium diffusion rate in comparison with the pristine sample. The modified material demonstrates dramatically enhanced electrochemical reversibility and stability under elevated temperature conditions. This is because the coated AlPO 4 layer reduces the contact area between the electrode and electrolyte and suppresses the formation of undesirable solid electrolyte interface films.

Pem, a member of homeobox genes, is an oncofetal gene which is preferentially expressed in reproductive tissues and in multiple tumor cell lines. However, the function of Pem in tumor cell lines has not been elucidated. Herein we report that the ectopic expression of Pem in TC-1, a human papillomavirus type 16 (HPV-16) E7-expressing surrogate cervical tumor cell line, demonstrated a significant increase in extracellular signal-regulated kinase (ERK) activity and multiple resistance to various apoptotic pressures from an E7-specific CD8(+) T cell-mediated immune response and anticancer drug treatment. The observed resistance to apoptotic death of the Pem-over-expressing TC-1 tumor cells (TC-1/Pem) was associated with the down-regulation of a pro-apoptotic molecule, such as BIM, and up-regulation of an anti-apoptotic molecule, such as Bcl-2 protein, which mediated ERK activation. We also observed that the intratumoral injection of an ERK inhibitor enhanced the therapeutic efficacy of E7-specific CD8(+) T cell adoptive transfer or anticancer drug treatment against the resistant TC-1/Pem tumor. This is the first evidence demonstrating an association between Pem and a signaling pathway, namely the ERK-mediated survival signal transduction pathway. Thus, our data indicate that activation of the ERK pathway represents a new mechanism of Pem-mediated multiple resistances and the present research will contribute to the development of a novel strategy in cancer therapy against Pem-over-expressing tumor cells.

Nafion®–silica nanocomposite membranes are successfully prepared by adding hydrophobic silica nanoparticles to a Nafion® solution. To distribute these nanoparticles evenly in the Nafion® matrix, various fluorosurfactants of different ionic character are employed. Fluorosurfactants with acid groups such as phosphonic acid and sulfonic acid play an important role in simultaneously increasing the homogeneous dispersion of silica nanoparticles, enhancing proton conductivity, and reducing the methanol permeability of the nanocomposite membranes. Therefore, the dispersion properties of inorganic fillers such as silica can significantly affect nanocomposite performance in direct methanol fuel cell (DMFC) applications, whereas surfactants, if used properly, can improve the nanocomposite membrane properties. In particular, a commercial fluorosurfactant containing a sulfonic acid group (Zonyl® TBS) at the end of the surfactant chain exhibits better miscibility with the Nafion® ionomer. This feature results in a reduction in the dimensional change of the nanocomposite membrane due to relatively lower water swelling and significantly reduced methanol permeability through the membrane. A membrane–electrode assembly (MEA) prepared from a Nafion®–silica nanocomposite membrane with TBS shows the highest DMFC performance in terms of voltage vs. current density (V–I) and power density vs. current density (P–I). The current densities at 0.4 V and 90 °C are 342, 508, and 538 mA cm−2 with 1, 3 and 5 M methanol being fed at the anode side, respectively.

Polymer electrolyte nanocomposite membranes were prepared by using a commercial perfluorinated sulfonic acid ionomer (Nafion ® ), nonporous hydrophilic fumed silica (Aerosil 380 ® ), and anionic fluorosurfactant (Zonyl ® TBS). The fluorosurfactant-containing an acid group, which includes sulfonic acid, contributes to well-dispersion of the silica nanoparticles and simultaneously enhances the proton conductivity of the nanocomposite membrane. Hence, the addition of inorganic fillers such as silica to the fluorosurfactant can significantly improve the properties of the Nafion ® -based polymer electrolyte nanocomposite membrane. The membranes were characterized in terms of their mechanical properties ( e.g. , dimensional change and tensile strength) and fundamental electrochemical properties ( e.g. , proton conductivity and current–voltage ( I – V ) curve). Zonyl ® TBS, a commercial anionic fluorosurfactant with sulfonic acid groups at the end of the surfactant chain, added to the Nafion ® matrix showed improved mechanical and electrochemical properties. The sulfonic acid groups in Zonyl ® TBS allowed for the additional transport of protons. As a result, the nanocomposite membrane with surfactant exhibited an improved performance. In a single cell test on a proton exchange membrane fuel cell (PEMFC), a membrane electrode assembly (MEA) prepared from the Nafion ® –silica nanocomposite membrane with TBS exhibited the highest PEMFC performance. The cell was fed with H 2 and O 2 humidified at 75 °C for 80 °C, respectively at ambient pressure. The current density of this membrane was 1600 mA cm −2 at 0.6 V and 80 °C, superior to 999 mA cm −2 for Nafion ® 112.

Trioctylphosphine (TOP)/Pd composites have been synthesized and used as a methanol-barrier material to modify the surface of Nafion 115. The TOP/Pd composites have been applied to the surface of Nafion instead of being incorporated into the Nafion matrix, to provide the best chance of maintaining the inherent proton conductivity of Nafion. The properties of the TOP/Pd-modified membrane, in terms of its conductivity and methanol permeability, as well as the performance of the membrane electrode assembly (MEA) in direct methanol fuel cell (DMFC), have been analyzed and compared with those of bare Nafion. The DMFC performance of the TOP/Pd-modified membrane is somewhat better than that of the bare Nafion one at methanol concentration of 2 M and significantly better at a high concentration of 5 M. The TOP/Pd-modified membrane is able to operate the DMFC using a high concentration of methanol, which can satisfy the requirement to reduce the reactant volumes for portable applications as well as to achieve high performance. In contrast to bare Nafion, the TOP/Pd-modified membrane with its well-adhering and crack-free modified surface shows effect on reducing the methanol loss.

Nafion is modified by incorporating poly(1-vinylimidazole)/Pd composites into the ion cluster channels of the membrane. The poly(1-vinylimidazole)/Pd-impregnated (PVI/Pd-impregnated) membranes is characterized by means of X-ray photoelectron spectroscopy (XPS), proton conductivity and methanol permeability measurements and compared with those of the untreated Nafion. The dependence of the membrane proton conductivity and methanol permeability on the poly(1-vinylimidazole) (PVI) and palladium contents in the PVI/Pd-impregnated Nafion is studied. The performance of the cells employing the PVI/Pd-impregnated Nafion is evaluated using a direct methanol fuel cell (DMFC) unit cell. It is found that the best cell performance is obtained when Nafion is impregnated with the PVI/Pd composite solution for 20 h. This result suggests that there exists an optimum content of palladium and PVI in the modified membrane to obtain a high-proton conductivity and low-methanol permeability that result in a high-cell performance.

We prepared a novel phosphoric acid-doped sulfonated poly(fluorinated arylene ether)s/poly(N-vinylimidazole) blend polymer and poly(tetrafluoroethylene) (PTFE) layered membrane. The thermal and electrochemical properties of the new layered membrane were investigated by thermogravimetric analysis (TGA), electrochemical impedance spectroscopy (EIS), as well as the performance of its membrane electrode assembly (MEA). The morphology of membrane was observed with field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). The fabricated membrane shows good mechanical property comparable to PBI membrane. The conductivity of new layered membrane was similar to that of polybenzimidazole (PBI) at high temperature. The single cell test showed that new PTFE layered membrane had a good performance over 150 °C. The PTFE layered membrane can be an alternative approach for PEMFC applications at high temperature.

The surface of Nafion was modified by applying palladium nanoparticles as methanol barrier materials to decrease methanol crossover and improve the performance of fuel cells. The properties of the Pd-modified membrane, in terms of conductivity, methanol permeability, percentage of liquid uptake as well as the performance of its membrane electrode assembly (MEA) in the direct methanol fuel cell, were analyzed and compared with those using bare Nafion. The modified membrane showed considerable improvement on reducing methanol loss without decreasing proton conductivity. The DMFC performance of modified membrane was superior to that of bare Nafion both at a typical fuel state of 2 M and at high concentration of 5 M, implying that the palladium-modified Nafion can be a good alternative approach for DMFC applications.

More than 1800 hundreds of millions of beverage cans are manufactured yearly over the world, which will pollute the globe environment without recycle. The recycle and regeneration estates of used beverage cans are highly profitable enterprises. Vacuum technologies are mature on a large scale today, and therefore, the re-melting process of used beverage cans (UBCs) does not have to use flux. Furthermore, the coating on UBCs becomes the key factor causing poor product quality. The present paper concerns removing the coating of UBCs and compares two different kinds of methods to remove the coating: a thermal method and a chemical reagent method. A new kind of reagent, thick sulfuric acid, was employed in the chemical reagent de-coating process. The de-coating ratio in the thermal method reached 93% at most, but the de-coating ratio reached 100% within 30 min in the chemical reagent method by using thick sulfuric acid. Recycling the used thick sulfuric acid was also supplied. A titanium yellow product can be simultaneously obtained. The experiments show that the chemical reagent method is more available than the thermal method, which will enhance the purity of the regeneration product enormously.

CeO 2 -coated LiMn 2 O 4 spinel cathode was synthesized using two-step synthesis method. All the samples exhibited a pure cubic spinel structure without any impurities in the XRD patterns. The results of the electrochemical performances on CeO 2 -coated electrode are compared to those of electrodes based on LiMn 2 O 4 spinel without CeO 2 coating. CeO 2 -coated LiMn 2 O 4 cathode improved the cycling stability of the electrode. The capacity retention of 2 wt% CeO 2 -coated LiMn 2 O 4 was more than 82% after 150 cycles between 3.0 and 4.4 V at room temperature and 82% after 40 cycles at elevated temperature of 60 °C. The amounts of dissolved manganese-ions in CeO 2 -coated LiMn 2 O 4 significantly are smaller than pristine LiMn 2 O 4 systems especially at elevated temperatures. Surface-modified LiMn 2 O 4 can suppress the dissolution reaction of manganese-ions at elevated temperature and clearly improve the cyclability of the spinel LiMn 2 O 4 cathode materials.

A novel method, a hydrothermal method, was firstly employed to prepare a catalyst of Pt supported on carbon nanotubes (Pt/CNTs) used in a proton exchange membrane fuel cell (PEMFC) in the present work. The catalyst was characterized through the IR spectrum, XRD, TEM and Image-Pro PLUS2 software. The results show that the pretreatment using a HNO 3 –H 2 O 2 redox system on CNTs opened the ports and removed a large quantity of impurities. Reaction temperature and time are important factors to determine the Pt granule size. The average size of the Pt nanoparticles is less than 1.94 nm with homogenous dispersion and narrow distribution under the optimal reaction conditions with a reaction time of 1.5 h at 140 °C. The hydrothermal method using the conventional Pt precursor H 2 PtCl 6 ·2H 2 O together with HCHO with brief operation will be a promising method to yield Pt nanoparticles for the Pt/CNTs catalyst.

LiNi 1− x Ti x O 2 (0 ≤ x ≤ 0.1) compounds have been synthesized by a direct molten-salt method that uses a eutectic mixture of LiNO 3 and LiOH salts. According to X-ray diffraction analysis, these materials have a well-developed layered structure (R3-m) and are an isostructure of LiNiO 2 . The LiNi 1− x Ti x O 2 (0 ≤ x ≤ 0.1) compounds have average particle sizes of 1–5 μm depending on the amount of Ti salt. Charge–discharge tests show that a LiNi 1− x Ti x O 2 (0 ≤ x ≤ 0.1) cathode prepared at 700 °C has an initial discharge capacity as high as 171 mA h g −1 and excellent capacity retention in the range 4.3–2.8 V at a current density of 0.2 mA cm −2 .

Olivine structure LiFePO 4 /C composite powders are synthesized as cathode materials for Li-ion batteries via a conventional solid-state reaction. Improvement in electrochemical performance has been achieved by using poly(vinyl alcohol) as the carbon sources for the as-prepared materials. The influence of the heat treatment on the physical and the electrochemical properties of LiFePO 4 /C materials is investigated. To examine the effect of added carbon content on the properties of materials, a one-step heat treatment has been employed with control of the PVA content in the precursor. Six samples were prepared with 0, 1, 3, 5, 10 and 30 wt.% PVA added to the raw materials. The particle size of LiFePO 4 decreases as the carbon content increases. Materials with medium carbon contents have a small charge-transfer resistance and thus exhibit superior electrochemical performance. Interestingly, for a LiFePO 4 /C composite with a low PVA content, an unusual plateau at 4.3 V is observed. It is considered that this is due to the Fe 3+ /Fe 4+ redox reaction of Fe 3+ compounds that are present as an impurity. For samples with a high PVA amount, a thicker carbon coating provides an obstacle to improve the electrochemical properties.

The dissolution of nickel oxide cathode in the electrolyte is one of the major technical obstacles to the commercialization of molten carbonate fuel cell (MCFC). To improve the MCFC cathode stability, the alternative cathode material for MCFC was prepared, which was made of Co/Ce-coated on the surface of Ni powder using a polymeric precursor based on the Pechini method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) were employed in characterization of the alternative cathode materials. The Co/Ce-coated Ni cathode prepared by the tape-casting technique. The solubility of the Co/Ce-coated Ni cathode was about 80% lower when compare to that of pure Ni cathode under CO2:O2 (66.7:33.3%) atmosphere at 650 °C. Consequently, the fine Co/Ce-coated Ni powder could be confirmed as a new alternative cathode material for MCFC.

Organic–inorganic hybrid composite membranes have been prepared and evaluated for polymer electrolyte membrane fuel cells (PEMFCs) at 100–140 °C. A series of synthesized poly (fluorinated arylene ether)s was sulfonated by fuming sulfuric acid (20% SO3). The zirconium phosphate composite membrane was prepared by soaking the sulfonated poly (fluorinated arylene ether)s stepwise in 1 M zirconyl chloride solution and 1 M phosphoric acid solution. The chemical, thermal, and electrochemical properties of the composite membrane were investigated by thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and unit cell test. The cell performance of the zirconium phosphate sulfonated poly (fluorinated arylene ether)s composite membrane was superior to that of the starting membrane at intermediate temperature, 100–140 °C. And the cell performance with composite membrane indicated stable behavior during experimentation when operating temperature maintained at 120 °C, whereas sulfonated poly (fluorinated arylene ether)s membrane was irreversible degradation under the same condition.

The properties of a new cathode material of nano-sized TiO 2 -coated Ni powder for application in molten carbonate fuel cells (MCFCs) are investigated. The material is prepared by a sol–gel method. X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM) with energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM) and Raman spectroscopy are employed to characterize the cathode material. The nano-sized TiO 2 particles are homogenously coated on the surface of the Ni powder. A stable LiTi 1− x Ni x O 2 phase is formed on the surface of the Ni powder during immersion in molten carbonate at 650 °C. The solubility of the TiO 2 -coated Ni cathode is about 50% lower compare with that of a pure Ni cathode.

CeO2-coated LiCoO2 particles were successfully synthesized by a sol–gel coating of CeO2 on the surface of the LiCoO2 powder and subsequent heat treatment at 700 °C for 5 h. The surface-modified and pristine LiCoO2 powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Auger electron spectroscopy (AES), slow rate cyclic voltammogram (CV), and differential scanning calorimetry (DSC). Cyclic voltammetry curves suggested that the CeO2 coating suppressed the phase transitions. Unlike pristine LiCoO2, the CeO2-coated LiCoO2 cathode exhibited better capacity retention than the pristine LiCoO2 electrode in the higher cutoff voltage. Differential scanning calorimetric data revealed the higher thermal stability of the CeO2-coated LiCoO2 electrode.

Fluorine-doped nanocrystalline tin dioxide materials (F:SnO 2 ) have been successfully prepared by the sol–gel process from a single molecular precursor followed by a thermal treatment at 450–650 °C. The resulting materials were characterized by FTIR spectroscopy, powder X-ray diffraction, nitrogen adsorption porosimetry (BET) and transmission electron microscopy (TEM). The mean particle size increased from 5 to 20 nm and the specific surface area decreased from 123 to 37 m 2 /g as the temperature of heat treatment was risen from 450 to 650 °C. Fluorine-doped nanocrystalline SnO 2 exhibited capacity of 560, 502, and 702 mA h/g with 48%, 50%, and 40% capacity retention after 25 cycles between 1.2 V and 50 mV at the rate of 25 mA/g, respectively. In comparison, commercial SnO 2 showed an initial capacity of 388 mA h/g, with only 23% capacity retention after 25 cycles.

Layered Li[Ni0.5−xMn0.5−xZr2x]O2 (x = 0, 0.025) have been prepared by the mixed hydroxide and molten-salt synthesis method. The individual particles of synthesized materials have a sub-microsize range of 200–500 nm, and LiNi0.475Mn0.475Zr0.05O2 has a rougher surface than that of LiNi0.5Mn0.5O2. The Li/Li[Ni0.5−xMn0.5−xZr2x]O2 (x = 0, 0.025) electrodes were cycled between 4.5 and 2.0 V at a current density of 15 mA/g, the discharge capacity of both cells increased during the first ten cycles. The discharge capacity of the Li/LiNi0.475Mn0.475Zr0.05O2 cell increased from 150 to 220 mAh/g, which is 50 mAh/g larger than that of the Li/LiNi0.5Mn0.5O2 cell. We found that the oxidation of oxygen and the Mn3+ ion concerned this phenomenon from the cyclic voltammetry (CV). Thermal stability of the charged Li[Ni0.5−xMn0.5−xZr2x]O2 (x = 0, 0.025) cathode was improved by Zr doping.

Ordinary graphite plate was impregnated by PTFE (polytetrafluoroethylene) scattering solution to make it suitable for fuel cell collector. The feasibility of impregnation process was investigated, and the process was optimized. SEM analysis showed that the depth of impregnation process was 2.50 mm. Porosity of graphite dropped from 18.20 percent to 3.29 percent after impregnation. There is no detectable leakage of H2, even at a pressure of 0.3 MPa after impregnation with PTFE. The impregnation process has no effect on graphite resistivity. Impregnation process successfully met the requirements for fuel cell graphite collector.

A high-performance LiNi 0.8 Co 0.2 O 2 cathode was successfully fabricated by a sol–gel coating of CeO 2 to the surface of the LiNi 0.8 Co 0.2 O 2 powder and subsequent heat treatment at 700 °C for 5 h. The surface-modified and pristine LiNi 0.8 Co 0.2 O 2 powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), slow rate cyclic voltammogram (CV), and differential scanning calorimetry (DSC). Unlike pristine LiNi 0.8 Co 0.2 O 2 , the CeO 2 -coated LiNi 0.8 Co 0.2 O 2 cathode exhibits no decrease in its original specific capacity of 182 mAh/g (versus lithium metal) and excellent capacity retention (95% of its initial capacity) between 4.5 and 2.8 V after 55 cycles. The results indicate that the surface treatment should be an effective way to improve the comprehensive properties of the cathode materials for lithium ion batteries.

Co/Mg solid solution coated Ni powder, where Mg-doped LiCoO2 is coated on NiO in molten carbonate, has been used as a new cathode material to reduce the solubility of NiO and to maintain the advantages of NiO cathode. The (Co/Mg)-coated NiO cathode was prepared by a coating Co/Mg solid solution on the surface of the Ni powder using a PVA assisted sol–gel method. The phase changes of the (Co/Mg)-coated Ni powder after immersed into Li/K eutectic carbonate mixtures at 550 °C ∼ 850 °C for 48 h was performed by XRD and Raman. SEM was used to study the particle morphologies. Co/Mg solid solution was coated on the surface of the Ni powder and Li(NiCoMg)O2 is formed on NiO in molten carbonate. It is expected that the Li(NiCoMg)O2 phase will reduce the solubility of NiO cathode in molten carbonate.

Preparation of catalyst layer in PEMFC electrodes was investigated. Toray carbon paper was used as diffusion layer, and Johnson–Matthey 20% Pt/C was employed as catalyst. Electrode contains neither PTFE nor carbon powder. The optimal catalyst layer composition was discovered by orthogonal test method, with the use of cell voltage–current curve and cyclic voltammogram curve. The optimal amount of the Nafion (ionomer) in the catalyst layer was found to be 1.4 mg / cm 2 when Pt loading was kept at 0.4 mg / cm 2 . Power density of PEMFC achieved 0.37 W / cm 2 with air and H 2 were used at the outlet pressure of 0.1 MPa.

We have successfully synthesized new superconductor EuSr 2 Cu 2 Nb 1− x Sn x O 8− y of the so-called Nb-1212 system, where Nb is substituted for Cu1 in the RE -123 ( RE = rare earth elements) type structure by the hole-doping through the partial substitution of Sn 4+ for Nb 5+ . The highest value of the superconductivity of the superconducting transition temperature, T c , is about 40 K at x = 0.2. This is the first superconductor in the Nb-1212 system.

Organic–inorganic composite membranes for operation above 100 °C in polymer electrolyte membrane fuel cells (PEMFCs) were prepared, characterized and cell-tested. Composite membranes were obtained by mixing organic polymers, which have a SO 3 H group as a proton conductor with inorganic material, SiO 2 , using the sol–gel process. Electron probe micro analyser (EPMA) was used to show the homogeneous and uniform distribution of SiO 2 . The physico-chemical properties of all membranes were investigated regarding their tensile strength, water uptake and thermogravimetric analyzer (TGA). Due to a higher water uptake and thermal stability of composite membranes, the cell performances at high temperatures above 100 °C, were improved. In addition, the SiOH group in the composite membrane was shown to play a major role in capturing water strongly and maintaining proton conductivity even at high temperature. Furthermore, the fuel cell performance of organic–inorganic composite membranes was superior to that of the Nafion membrane at high current density over all ranges of temperature.

New proton exchange membranes were prepared and evaluated as polymer electrolytes for a proton exchange membrane fuel cell (PEMFC). Two types of fluorinated poly(arylene ether)s (FPAEs) were synthesized by nucleophilic aromatic substitution of decafluorobiphenyl (DFBP) with 4,4′-(hexafluoroisopropylidene)diphenol (HFDP) and bisphenol-A (BPA). The FPAEs so prepared were converted into proton exchange polymers by sulfonation with fuming sulfuric acid (30% SO3). The FPAEs and sulfonated-fluorinated poly(arylene ether)s (S-FPAEs) with various sulfonation levels were characterized using 1 H NMR, thermogravimetric analysis (TGA) and back titration, and then successfully evaluated as proton exchange membranes (PEM) with unit cell operation. power output measurements of S-DFBP-HFDP carried out at a cell temperature of 80 °C. They exhibited a maximum power density of 425.5 mW/cm2 at 1150 mA/cm2.

In this study, we made a novel alternative cathode material of molten carbonate fuel cell (MCFC) using electroless deposition of Co on the surface of the Ni powder. Using this manufacturing method, we expect that economical and large-scale cathode can be made easily. The cathode prepared by this method formed LiCo 1− y Ni y O 2 phase in molten (Li 0.62 K 0.38 ) 2 CO 3 at 650 °C under CO 2 :O 2 =66.7:33.3% atmosphere, its solubility is 40% lower than that of NiO cathode. In the unit cell test, the performance of the cell composed of Co-coated Ni cathode was same as that of the cell composed of NiO cathode. Thus the cathode made by Co-coated Ni powder used as an alternative cathode can maintain the advantages of NiO cathode and lengthen the lifetime of MCFC.

Single phases of M-substituted lithium cobalt oxides, HT-LiCo 0.8 M 0.2 O 2 (M=Al, Ni), were prepared by molten salt synthesis (MSS) method using coprecipitated Co–M hydroxides in 0.59 LiNO 3 –0.41 LiOH. The prepared powders consisted of well-developed particles with spherical shape and the particle size was around 150 nm in diameter. Among them, HT-LiCo 0.8 Al 0.2 O 2 showed an inferior cyclic performance and a smaller discharge capacity than HT-LiCo 0.8 Ni 0.2 O 2 , even though the former is more structurally stable than the latter. Structural analysis of HT-Li x Co 0.8 Al 0.2 O 2 indicated that the Al substitution, causing an enhanced internal resistance for lithium ion diffusion, is responsible for the capacity fading. In the meanwhile, HT-Li x Co 0.8 Ni 0.2 O 2 with large c layer spacing showed as high as 146 mAh/g at the first cycle and 130 mAh/g at the twentieth cycle.

Recently the role of surgical and interventional therapy has been increasing in the management of ischemic stroke due to carotid artery stenosis or occlusion. Various treatment modalities have been reported to be beneficial if these procedures are performed within therapeutic window and with optimal indication: intravascular thrombolysis for acute carotid occlusion, extracranial–intracranial (EC–IC) bypass surgery for hemodynamic ischemic stroke, and carotid endarterectomy (CEA) or percutaneous transluminal angioplasty and stenting (PTAS) for severe symptomatic carotid artery stenosis or occlusion. Recent management strategies will be described from literature review and our limited experience for enhancing the effectiveness of treatment modalities for carotid artery stenosis or occlusion.

Iodine-containing, cation-deficient, lithium manganese oxides (ICCD-LMO) are prepared by reaction of MnO2 with LiI. The MnO2 is completely transformed into spinel-structured compounds with a nominal composition of Li1−δMn2−2δO4Ix. A sample prepared at 800 °C, viz. Li0.99Mn1.98O4I0.02, exhibits an initial discharge capacity of 113 mA h g−1 with good cycleability and rate capability in the 4-V region. Iodine-containing, lithium-rich lithium manganese oxides (ICLR-LMO) are also prepared by reaction of LiMn2O4 with LiI, which results in a nominal composition of Li1+xMn2−xO4Ix. Li1.01Mn1.99O4I0.02 shows a discharge capacity of 124 mA h g−1 on the first cycle and 119 mA h g−1 a on the 20th cycle. Both results indicate that a small amount of iodine species helps to maintain cycle performance.

To elucidate the mechanism of gas generation during charge–discharge cycling of a lithium-ion cell, the generated gases and passive films on the carbon electrode are examined by means of gas chromatography (GC) and Fourier transform infrared (FTIR) spectroscopy. In ethyl carbonate/dimethyl carbonate and ethyl carbonate/diethyl carbonate 1 M LiPF 6 electrolytes, the detected gaseous products are CO 2 , CO, CH 4 , C 2 H 4 , C 2 H 6 , etc. The FTIR spectrum of the surface of the carbon electrode shows bands which correspond to Li 2 CO 3 , ROCO 2 Li, (ROCO 2 Li) 2 , and RCO 2 Li. These results suggest that gas evolution is caused by electrode decomposition, reactive trace impurities, and electrolyte reduction. The surface of the electrode is composed of electrolyte reduction products. When 0.05 M Li 2 CO 3 is added as an electrolyte additive, the total volume of generated gases is reduced, and the discharge capacity and the conductivity of lithium-ions are increased. These results can be explained by a more compact and thin ‘solid electrolyte interface’ film on the carbon electrode formed by Li 2 CO 3 , which effectively prevents solvent co-intercalation and carbon exfoliation.

The crystal structures of n =3 Dion–Jacobson phases M La 2 Ti 2 TaO 10 ( M =Cs, Rb) and NaLa 2 Ti 2 TaO 10 · x H 2 O ( x =2, 0.9, 0) have been investigated by the Rietveld analysis of their powder XRD patterns. These compounds show the new-type ordering sequence of (Ti 1/2 Ta 1/2 )O 6 –TiO 6 –(Ti 1/2 Ta 1/2 )O 6 in the tripled octahedra, corresponding to the niobium analogs of M La 2 Ti 2 NbO 10 . They crystallize in the tetragonal system P 4/ mmm with lattice constants of a =3.84733(9) and c =15.4364(4) A for CsLa 2 Ti 2 TaO 10 , and a =3.8342(2) and c =15.2776(9) A for RbLa 2 Ti 2 TaO 10 . Sodium-exchanged phase was easily hydrated to NaLa 2 Ti 2 TaO 10 ·2H 2 O, belonging to the space group I 4/ mmm with a =3.8399(3) and c =34.288(3) A. Upon firing, NaLa 2 Ti 2 TaO 10 ·2H 2 O was dehydrated to NaLa 2 Ti 2 TaO 10 ·0.9H 2 O with P 4/ mmm at around 100°C and then NaLa 2 Ti 2 TaO 10 with I 4/ mmm at above 200°C. The Na cations in two hydrates were surrounded with six oxygens, forming face-shared octahedra along (110) direction. These structural models, especially for the coordination environment of Na cations, were proposed for the first time.