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Carbon monoxide (CO) is an odorless, colorless, tasteless, extremely flammable, and highly toxic gas. It is produced when there is insufficient oxygen supply during the combustion of carbon to produce carbon dioxide (CO2). CO is produced from operating engines, stoves, or furnaces. CO poisoning occurs when CO accumulates in the bloodstream and can result in severe tissue damage or even death. Many types of CO sensors have been reported, including electrochemical, semiconductor metal-oxide, catalytic combustion, thermal conductivity, and infrared absorption-type for the detection of CO. However, despite their excellent selectivity and sensitivity, issues such as complexity, power consumption, and calibration limit their applications. In this study, a fabricbased colorimetric CO sensor is proposed to address these issues. Potassium disulfitopalladate (II) (K2Pd(SO3)2) is dyed on a polyester fabric as a sensing material for selective CO detection. The sensing characteristics and performance are investigated using optical instruments such as RGB sensor and spectrometer. The sensor shows immediate color change when exposed to CO at a concentration that is even lower than 20 ppm before 2 min. The fast response time of the sensor is attributed to its high porosity to react with CO. This easy-to-fabricate and cost-effective sensor can detect and prevent the leakage of CO simultaneously with high sensitivity and selectivity toward CO.

As hydrogen (H2) gas is highly reactive and explosive in ambient atmosphere, its prompt detection in industrial areas is imperative to prevent serious accidents. In particular, high-performance H2 sensors that can promptly detect even low-concentrations of H2 gas are necessary for safety. Carbon nanotubes (CNTs) have a large surface area and a high surface-to-volume ratio, and therefore, they are suitable for use as sensing materials in gas sensors. Moreover, gold, platinum, and palladium are known to be excellent catalyst metals that increase reactivity with H2 gas through the catalytic effect referred to as spill-over mechanism. In this study, a CNT felt sensor with a palladium (Pd) layer was fabricated, and its reactivity with H2 was evaluated. The sensitivity of a CNT felt sensor to H2 gas at room temperature was found to improve when coated with Pd layer.

Palladium-coated multi-walled carbon nanotube (Pd-MWCNT) nanocomposites have been experimentally proven to show highly improved hydrogen (H2) gas detection characteristics at room temperature when compared with single MWCNTs. In this context, we develop an efficient and convenient method for forming nanocomposites by coating Pd nanoparticles on an MWCNT film. Furthermore, we test the applicability of the nanocomposites as sensing materials in detecting H2 gas at room temperature in a reliable and sensitive manner in contrast with ordinary metal-oxidebased gas sensors that operate at high temperatures. We first study the detection efficacy of the Pd-MWCNT film relative to pure MWCNT film. Subsequently, we investigate the Pd-MWCNT sensor’s sensitivity over time for different gas concentrations, the sensor response time, and sensor reproducibility and reliability under various conditions including bending tests. Our sensor exhibits stable reliable detection characteristics and excellent structural flexibility.

Powerful sunlight, a high water temperature, and stagnation in the water flow induce eutrophication in rivers and lakes, which destroys the aquatic ecosystem and threatens the downstream water supply systems. Accordingly, it is very important to perform real-time measurements of nutrients that induce algal growth, especially total phosphorus, to preserve and manage the aquatic ecosystem. To conduct quantitative analysis of the total phosphorus in the aquatic ecosystem, it is essential to perform a pretreatment process and quickly separate the phosphorus, combined with organic and inorganic materials, into a phosphate. In this study, the sandblasting process was used for the physical etching of the wafer, and photocatalytic materials were deposited on the surface with various roughness in order to improve the photocatalytic reaction surface and efficiency. The photocatalytic reaction was applied to combine the pretreated sample with the coloring agent for color development, and the absorbance of the colored sample was analyzed quantitatively to compare and evaluate the characteristics, followed by the surface increase in the photocatalytic materials. In addition, the pretreatment and measurement parts were materialized in a single chip to produce a small and light total phosphorus analysis sensor.

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.

In this study, experimental variables pertaining to the formation of nano-pillar arrays using p-type silicon were optimized by controlling current density and chamber temperature. Three factors aff...

In this study, we have studied coating method using high reflective White silicon on the whole Zener diode in order to resolve the reducing the luminance of the LED problem caused by the Ze...

Comparative properties of pin-type amorphous silicon (a-Si:H) thin-film solar cells with different PH3 flows for the i-layer and the presence of a buffer layer at the p–i interface were inv...

Squarylium-based colorimetric hydrogen sulfide (H2S) chemosensors (SQ1, SQ2, and SQ3) were developed, and their detection properties were systematically characterized. SQ1 exhibited rapid and high resolution H2S sensing properties through significant color changes detectable by naked-eye with limit of detection as low as 7.2 ppb. SQ1 also showed excellent selectivity for H2S detection over other relevant anions and nucleophiles. Sensing mechanisms of SQ1 were investigated based on spectroscopic and 1H NMR analyses with quantum calculations. Furthermore, SQ1 showed an efficient response to H2S under versatile conditions in the solution, solid, and dyed fabric states, which suggests applicability of SQ1 to simple, low-cost, and practical H2S sensors.

The proposed study describes the development of a carbon nanotube (CNT)-based gas sensor capable of detecting the presence of hydrogen (H2) gas at room temperature. CNT yarn used in the proposed sensor was fabricated from synthesized CNT arrays. Subsequently, the yarn was treated by means of a simple one-step procedure, called acid treatment, to facilitate removal of impurities from the yarn surface and forming functional species. To verify the proposed sensor’s effectiveness with regard to detection of H2 gas at room temperature, acid-treated CNT and pure yarns were fabricated and tested under identical conditions. Corresponding results demonstrate that compared to the untreated CNT yarn, the acid-treated CNT yarn exhibits higher sensitivity to the presence of H2 gas at room temperature. Additionally, the acid-treated CNT yarn was observed to demonstrate excellent selectivity pertaining to H2 gas.

A series of earthquake events give impetus to research on the ductile fracture behavior of steel materials. In the last decades, many fracture models have been developed and utilized in the mechanical or aerospace engineering. Nevertheless, very little application to structural members used in the construction industry has been made due to the lack of a suitable model for the fracture behavior of constructional steel. This paper presents the experimental and finite element (FE) technique to predict ductile fracture in mild carbon structural steel (SS275) sheets, which has been widely used in building structures. The post-necking true stress–strain responses were successfully estimated using the weighted-average method. The Bao and Wierzbicki (BW) model, which requires only two model parameters, was selected for the identification of fracture locus. Each model parameter was calibrated from uniaxial tension and in-plane shear specimens with the aid of digital image correlation (DIC) and finite element analysis. Fracture simulation was then performed and validated based on the experimental results of the specimens under combined tension and shear stress state.

Simple Summary Octamer-binding transcription factor 4 (OCT4) plays an important role in early embryonic development, but is rarely expressed in adults. However, in many cancer cells, this gene is re-expressed, making the cancer malignant. This present study revealed that inhibiting OCT4 transcriptional activity induces cancer cell differentiation and growth retardation. Specifically, when the phosphorylation of OCT4 serine 236 increases by interfering with the binding of protein phosphatase 1 (PP1) to OCT4, OCT4 loses its transcriptional activity and cancer cells differentiate. Therefore, this study presents the basis for the development of protein-protein interaction inhibitors that inhibit the binding of OCT4 and PP1 for cancer treatment. Abstract Octamer-binding transcription factor 4 (Oct4) plays an important role in maintaining pluripotency in embryonic stem cells and is closely related to the malignancies of various cancers. Although posttranslational modifications of Oct4 have been widely studied, most of these have not yet been fully characterized, especially in cancer. In this study, we investigated the role of phosphorylation of serine 236 of OCT4 [OCT4 (S236)] in human germ cell tumors (GCTs). OCT4 was phosphorylated at S236 in a cell cycle-dependent manner in a patient sample and GCT cell lines. The substitution of endogenous OCT4 by a mimic of phosphorylated OCT4 with a serine-to-aspartate mutation at S236 (S236D) resulted in tumor cell differentiation, growth retardation, and inhibition of tumor sphere formation. GCT cells expressing OCT4 S236D instead of endogenous OCT4 were similar to cells with OCT4 depletion at the mRNA transcript level as well as in the phenotype. OCT4 S236D also induced tumor cell differentiation and growth retardation in mouse xenograft experiments. Inhibition of protein phosphatase 1 by chemicals or short hairpin RNAs increased phosphorylation at OCT4 (S236) and resulted in the differentiation of GCTs. These results reveal the role of OCT4 (S236) phosphorylation in GCTs and suggest a new strategy for suppressing OCT4 in cancer.

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.

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.

modified powder is almost same as that of the pristine NiOpowder. The existence of Ti is identified through energydispersive spectroscopy (EDS) and these data demonstratethe homogeneous distribution of Ti without severe agglome-ration after annealing.The structural change in the modified powders after surfacemodification was investigated by X-ray diffraction (XRD).Figure 2 shows XRD data of the samples annealed at 650

Temozolomide is the current first-line treatment for glioblastoma patients but, because many patients are resistant to it, there is an urgent need to develop antitumor agents to treat temozolomide-resistant glioblastoma. Gossypol, a natural polyphenolic compound, has been studied as a monotherapy or combination therapy for the treatment of glioblastoma. The combination of gossypol and temozolomide has been shown to inhibit glioblastoma, but it is not clear yet whether gossypol alone can suppress temozolomide-resistant glioblastoma. We find that gossypol suppresses the growth of temozolomide-resistant glioblastoma cells in both tumor sphere and adherent culture conditions, with tumor spheres showing the greatest sensitivity. Molecular docking and binding energy calculations show that gossypol has a similar affinity to the Bcl2 (B-cell lymphoma 2) family of proteins and several dehydrogenases. Gossypol reduces mitochondrial membrane potential and cellular ATP levels before cell death, which suggests that gossypol inhibits several dehydrogenases in the cell&rsquo, s metabolic pathway. Treatment with a Bcl2 inhibitor does not fully explain the effect of gossypol on glioblastoma. Overall, this study demonstrates that gossypol can suppress temozolomide-resistant glioblastoma and will be helpful for the refinement of gossypol treatments by elucidating some of the molecular mechanisms of gossypol in glioblastoma.

This paper proposes a simple and efficient method to develop a nanocomposite by depositing platinum (Pt) nanoparticles on a carbon nanotube (CNT) sheet, and experimentally verifies the applicability of the proposed nanocomposite as a reliable and sensitive carbon monoxide (CO) gas sensor that operates at room temperature. A Pt-CNT nanocomposite shows improved CO gas sensing properties compared with the pristine CNT sheet. Owing to its large surface area and high conductivity, a CNT sheet exhibits improved sensitivity and fast response and recovery times. Based on the Pt-CNT nanocomposite implemented by the proposed method, we fabricated a Pt-CNT sheet-based CO gas sensor operating at room temperature and experimentally verified its stable and reliable room temperature sensing properties and excellent structural flexibility.

A gadolinium (Gd) complex with carboxylic acid was synthesized by using a neutralization chemical reaction. Gd (0.5%) was doped into a liquid scintillator by using a solvent-solvent extraction under controlled pH. Linear alkyl benzene (LAB) was used as a scintillation solvent. We measured several important physical and optical properties. The preparation, the synthesis procedures and the characterization of the resulting gadolinium-loaded, LAB-based, liquid scintillator are described in this paper.

A simple method was developed for the analysis of seven stilbene-type fluorescent whitening agents (FWAs) in paper materials by ion-pair reversed-phase high-performance liquid chromatography with fluorescence detection. These stilbene-type FWAs included two disulfonate, two tetrasulfonate, and three hexasulfonate compounds. After optimization of chromatographic conditions, the FWAs were satisfactorily separated using a reversed-phase column (RP-18) with the following isocratic mobile phase: methanol-water (60:40) containing 17.5 mM TBABr and 10 mM citrate buffer (pH = 7.0). The calibration plot was linear in the range from 5 to 500 ng/mL for two disulfo-FWAs and from 1 to 500 ng/mL for the other five FWAs. Precision levels of the calibration curve as indicated by RSD of response factors were 1.2 and 8.1%. Limits of quantitation (LOQ) ranged from 1.2 to 11 ng/mL.

The proton exchange membrane fuel cell (PEMFC) has received a great attention as a clean power generator to convert the chemical energy of hydrogen to electric energy electrochemically. It has major advantages for the portable electronic devices and transportation/stationary power systems such as the high power density and high energy efficiency, rapid start-up, etc. One of the most widely used proton exchange membrane is perfluorosulfonic acid (Nafion, DuPont Co.). It has excellent thermal and chemical stability and high proton conductivity below 80 C. However, PEMFC with Nafion membrane shows the poor performance at higher temperature due to the dehydration and low proton conductivity of the membrane. Recently, many studies have been performed to develop proton conducting membrane for operation above 100 C because the high temperature operation of PEMFC has the advantages of low CO poisoning of Pt catalyst and simple thermal and water management. Even if the Nafion composite membranes with incorporation of water retentive and inherent proton conductive fillers have been studied extensively under elevated temperature and low humidity conditions, the proton conductivity of the composite membrane is occasionally lower than the pristine Nafion because the wellconnected ionic domain of the Nafion is deformed by the inorganic fillers. In this paper, we report the physico-chemical and electrochemical properties of the phosphoric acid-functionalized mesoporous silica/Nafion composite membrane. The mesopore of silica increases the water retention capacity more effectively, and the phosphor-silicate has thermally and chemically stable silica networks and the surface-terminated phosphate interacts strongly with the water molecules. Therefore, the phosphoric acid-functionalized mesoporous silica/Nafion composite membrane shows the higher proton conductivities and cell performance than the pristine Nafion at high temperature and low humidity. The morphology and particle size of the prepared inorganic materials were investigated by TEM, and the data are shown in Figure 1. The shape of mesoporous SiO2 is spherical with a diameter of ~45 nm and their pore size is ~5 nm as shown in Figure 1(a). The specific surface area and the mean pore size of the mesoporous SiO2 are 560 m ·g and 4.82 nm, respectively. However, the morphology of the phosphoric acid-functionalized mesoporous SiO2 was quite different from that of pristine one. As shown in Figure 1(b)-(d), the porous structure is destructed and particle size increases as the annealing temperature increases after the mixing of mesoporous SiO2 with phosphoric acid. Figure 1(b) shows the sample heated at 80 C in the vacuum, and the result shows that the porosity of the sample is slightly reduced. With an annealing at 200 C, the morphology change is significant in that the mesopore disappears and large pore is formed. Interestingly, the further annealing above 200 C, the pore completely disappears and their particle size also increases, because of the formation of phosphor silicate through the reaction of silica and phosphoric acid, and the bulk-like phosphor silicate phase is confirmed by XRD (not shown for brevity). In order to elucidate the chemical structure of the prepared

The layered lithium-manganese oxide () as a cathode material of lithium ion secondary batteries was prepared and characterized the physico-chemical and electrochemical properties. The morphological and structural changes of MnO(OH) and are closely connected to the changes of electrochemical properties. The crystallinity of is enhanced as the annealing temperature increase, but its capacity is reduced due to the easier structural changes of less crystalline than highly crystalline one. Moreover, the addition of buffer material such as MnO(OH) into cathode causes to reduce the morphological and structural changes of layered and increase the discharge capacity and cycleability.

In this study, a cDNA microarray was developed from over 60,000 mRNA readings to analyze the expression profiles of transcriptomes of Haematococcus lacustris under astaxanthin-inducing culture conditions, high irradiance and nitrate starvation. Among 20,033 genes on the cDNA microarray, 2,675 genes exhibited a twofold or greater difference in expression. Of these, 1,333 genes were up-regulated and 1,342 genes were down-regulated. A significant decrease in the expression of chlorophyll biosynthesis and light harvesting complex (LHC) related genes were observed under astaxanthin inducing conditions (forming red cyst cells). On the other hand, respirationrelated genes, lipid metabolism-related genes and stress response-related genes were activated in the red cyst cells under stress conditions. These results enabled a better understanding of the cell responses during stress induction of H. lacustris such as photosynthesis, respiration, and some biopathways.

Sulfonated poly(fluorinated arylene ether)s (SDF-F)/poly[(N-vinylimidazole)-co-(3-methacryloxypropyl-trimethoxysilane)] (poly(VI-co-MPS))/poly(tetrafluoroethylene) (PTFE) is prepared for a high temperature proton exchange membrane fuel cell (PEMFC). The reaction of the membrane with phosphoric acid forms silicate phosphor, as a chemically bound proton carrier, in the membrane. Thus-formed silicate phosphor, nitrogen in the imidazole ring, and physically bound phosphoric acid act as proton carriers in the membrane. The physico-chemical and electrochemical properties of the membrane are investigated by various analytical tools. The phosphoric acid uptake and proton conductivity of the SDF-F/poly(VI-co-MPS)/PTFE membrane are higher than those of SDF-F/PVI/PTFE. The power densities of cells with SDF-F/poly(VI-co-MPS)/PTFE membranes at 0.6 V are 286, 302, and 320 mW at 150, 170, and 190 , respectively. Overall, the SDFF/poly(VI-co-MPS)/PTFE membrane is one of the candidates for anhydrous HT-PEMFCs with enhanced mechanical strength and improved cell performance.

Various TiO2-coated ZnO samples were prepared by the sol−gel method for use as the anode active materials of Ni−Zn secondary batteries. At a low annealing temperature, the added titanium does not r...

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.

C의 용융탄산염과 산소 분위기조건에서 안정하고 높은 전기 전도도를 가지는 장점이 있다. 그러나, 장시간 운전 시 양극에서전해질로의 Ni dissolution은 전지 내부의 단락을 초래하여 전지의 수명을 단축시킨다. 본 연구에서는 대체 전극물질로서 코발트와 나이오븀을 코팅시킨 NiO 전극을 제조하였으며, 이렇게 제조된 전극은 기존 NiO전극과 비교하여 낮은 Ni dissolution과 안정되고 우수한 전기화학 성능을보임을 확인하였다.Abstract: NiO is commonly used as the cathode for the molten carbonate fuel cell due to itsstability and high electrical conductivity in molten carbonates and oxygen atmosphere. However,long-term operation of MCFC has a serious problem which is the degradation of cathode material,the so-called Ni dissolution. In the present study, we have attempted to synthesize a new alter-native cathode material as Co/Nb-coated NiO cathode. The results obtained in this study suggestthat the Co/Nb-coated NiO cathode can be utilized as having lower dissolution and higher cellperformance than those of the pure NiO cathode.Keyword: MCFC, Cathode, Ni dissolution

Polycrystalline samples of RE 0.6Ca0.4Ba1.6Sr0.4Cu3O6 (RE = Nd, Gd, Dy, Y, Yb, Lu) without oxygen in the Cu(1)O chain have been prepared by the conventional solid-state reaction method. No superconductivity appears for larger RE = Nd, Gd, Dy, while superconductivity with T c ~50 K appears for smaller RE = Y, Yb, Lu. This is presumably because holes produced by the Ca-substitution for RE are more supplied to the conductive Cu(2)O2 plane than to Cu(1) as the lattice becomes small. The maximum T c = 53 K for RE = Lu is considerably lower than 90 K for REBa2Cu3O7. This may be due to the low hole-concentration in the Cu(2)O2 plane.

The surface modified LiMn2O4 materials with Li-Fe composites were prepared by a sol-gel method to improve the elec- trochemical performance of LiMn2O4 and were characterized by X-ray diffraction (XRD), X-ray photoelectron spec- troscopy (XPS), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and transmission electron microscopy (TEM)-EDS. XRD results indicate that all the samples (modified and pristine samples) have cubic spinel structures, and XRD, XPS, and TEM-EDS data reveal the formation of Li(LixFexMn2-2x)O4 solid solution on the sur- face of particles. For the electrochemical properties, the modified material demonstrated dramatically enhanced reversibility and stability even at elevated temperature. These improvements are attributed to the formation of the solid solution, and thus-formed solid solution phase on the surface of LiMn2O4 particle reduces the dissolution of Mn ion and suppresses the Jahn-Teller effect.

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.

The consolidation process of ultra fine Si powders, generated as by-product during the decomposition process of silane gases, was systematically investigated for use as economical solar-grade feedstock. Si powder compacts were tried to fabricate by a consolidation process without a binding agent and then their density ratio and strength were evaluated. The Si powders in as-received state were not pure enough to be used alone as solar grade feedstock material. After the adequate chemical treatments, a sufficiently high purity above solar-grade was able to be achieved.

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.

Lithium ion secondary battery has been applied widely to portable devices, and has been studied for application to high power electric cell system such as power tool or hybrid electronic vehicle. The structure change of the electrodes materials occur when lithium ions move between electrodes. Neutron or X-rays can analyze the structure of electrode. The advantage of X-rays is convenient in test. However X-rays is scattered by electron cloud in atoms. Therefore, The elucidation for correct position of lithium is difficult with X-rays because lithium has small atomic weight. Neutron analysis techniques could solve this problem. In this review, We wish to discuss about structure analysis and the principle of structural characterization method using neutron beam source.

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.