Due to the shortage of fossil fuel and the environmental pollution problem, solar energy applications have drawn a lot of attention worldwide. This paper reports the use of the latest patented distributed photovoltaic (PV) power system design, including the two possible maximum power point tracking (MPPT) algorithms, a power optimizer, and a PV power controller, in grid-connected and standalone applications. A distributed PV system with four amorphous silicon thin-film solar panels is used to evaluate both the quadratic maximization (QM) and the Steepest descent (SD) MPPT algorithms. The system’s design is different for the QM or the SD MPPT algorithm being used. The test result for the grid-connected silicon-based PV panels will also be reported. Considering the settling time for the power optimizer to be 20 ms, the test result shows that the tracking time for the QM method is close to 200 ms, which is faster when compared with the SD method whose tracking time is 500 ms. Besides this, the use of the QM method provides a more stable power output since the tracking is restricted by a local power optimizer rather than the global tracking the SD method uses. For a standalone PV application, a solar-powered boat design with 18 PV panels using a cascaded MPPT controller is introduced, and it provides flexibility in system design and the effective use of photovoltaic energy.

Photovoltaic (PV) system under partial shading condition has been discussed by many researchers. By using the distributed PV system, one can control every PV panel independently in order minimum effect caused by panel shading and mismatching. To maximum the use of microcontroller and further to reduce the cost for the distributed PV system, research work switches to the development of multivariable MPPT technique. This paper reports the design of the power optimizer and the central MPPT controller associated with the distributed PV system. Performance test by several MPPT methods including the multi-variable particle swarm optimization (PSO) and the steepest decent method is presented. Thin film and poly-Si types of PV panels in various format connecting to the battery bank or the power grid are examined. It is found that multi-variable MPPT of the steepest decent method gives faster convergent tracking result, and therefore the tracking efficiency is improved and the transient power output variation is minimized. Distributed PV system with more than 10 PV panels using cascaded MPPT controller is also possible, which provides the flexibility of system design and the effective use of photovoltaic energy.

Effect of micro–meso porosity of MWW zeolites on the catalytic linear alkylbenzene synthesis was studied.

This paper identifies the partial shading problem of a PV module using the one-diode model and simulating the characteristics exhibiting multiple-peak power output condition that is similar to a PV array. A modified particle swarm optimization (PSO) algorithm based on the suggested search-agent deployment, retracking condition, and multicore operation is proposed in order to continuously locate the global maximum power point for the PV system. Partial shading simulation results for up to 16 modules in series/parallel formats are presented. A distributed PV system consisting of up to 8 a-silicon thin film PV panels and also having a dedicated DC/DC buck converter on each of the modules is tested. The converter reaches its steady state voltage output in 10 ms. However for MPPT operation, voltage, and current measurement interval is set to 20 ms to avoid unnecessary noise from the entire electric circuit. Based on the simulation and experiment results, each core of the proposed PSO operation should control no more than 4 PV modules in order to have the maximum tracking accuracy and minimum overall tracking time. Tracking for the global maximum power point of a distributed PV system under various partial shading conditions can be done within 1.3 seconds.

Several synthesis parameters including silica precursor, alumina precursor and composition of reactant gel, during hydrothermal synthesis of SAPO-37, were studied. It was found that silica species is one indispensable component for the formation of SAPO-37. SAPO-37 could be synthesized only in a very narrow range within weak basic condition of pH =  8 ~ 9. In the use of no silica starting gel even SAPO-37 seeding, AlPO4-5 and SAPO-5 dominated the zeolite product without SAPO-37 formation. A new ion exchange procedure was developed for the removal of tetrapropyl ammonium (TPA) template from SAPO-37 with enhanced thermal stability by which the structure damage in SAPO-37 caused by the excessive steam during TPA burning could be avoided.

This paper evaluates the performance of a serial and parallel connected distributed PV power generation system built by silicon thin film solar cell using the steepest decent MPPT method. Simulation and experimental test results show that this method can track the MPPT nearly 1s under various insolation or partial shading conditions.

Several environmental benign processes have been developed for transformation of aromatics utilizing zeolite catalysts with controlled porosities and diffusivities. This review aims to summarize the available pore engineering techniques for zeolites and relevant enhancement in catalytic performances during aromatics conversion reactions, especially in terms of para-dialkylbenzene product selectivity and stability.

In this review, we discuss the recent advances in both of non-zeolitic and zeolitic solid acid catalysts for linear alkylbenzene (LAB) synthesis with special focus on improvements of 2-LAB isomer selectivity and catalyst stability. Effects of post treatment methods particularly dealumination and desilication on the catalytic performance of mordenite in terms of mesoporosity, diffusivity and deactivation mechanism are extensively reviewed. Perspective trends in the development of mesoporous zeolites for LAB synthesis are also presented.

Lactic esters were synthesized with good yields by the reaction between lactic acid and n-butanol/ethanol over titania-silica binary oxides. These catalysts had various atomic ratios and were prepared by a coprecipitation method. XRD, n-butylamine adsorption, nitrogen adsorption, and SEM/EDS were used to characterize the oxides. In general, the turnover frequency for ester formation increased with increasing Ti content. However, the catalyst with Ti/Si atomic ratio = 1/3 (TS13) exhibited the highest ester yield (92.3%) because it had the largest surface area and the greatest amount of acid sites. The optimum Ti/Si atomic ratio for esterification is different from that (Ti/Si similar to 9/1) reported previously for alkene isomerization. For lactic acid esterification, different optimum catalyst compositions were observed for Ti-Si, Ti-Al, and Ti-Zr mixed oxides (the best Ti/M atomic ratios = 1/3, 1/1, and 3/1 when M = Si, Al, and Zr, respectively), which might be caused by the electronegativity and acid strength differences.

High thermal conductivity films were prepared by blending silver nanowires (AgNws) with epoxy resins. 3-Aminopropyltriethoxysilane (APTES) silane was used to modify the AgNws surface, to produce a high aspect ratio and high thermal conductivity. A thermal interface material with a high thermal conductivity coefficient was used to form a thermal channel in epoxy resins, which possess superior thermal conductivity when the composite contained AgNws higher than 50 phr. The phr ratio of AgNws to silver nanoparticles (AgNps) loading was 50:300 when the thermal conductivity coefficient of the composite reached approximately 8 W/mK. The composite density ratio of AgNws (50 phr) to AgNps (300 phr) was 1.512:3.650 (g/cm(3)), which suggests that the density can be reduced by more than 50% in weight when AgNws, rather than AgNps, were used to prepare thermal interface composites. Furthermore, the adhesion test indicates that the composite containing a lower loading of AgNws exhibits higher adhesive property than that of the composite containing a higher loading of AgNps with a similar thermal conductivity coefficient, thereby resulting in enhanced adhesiveness between devices. (C) 2013 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers.

To improve the stability of the modified mordenite for resolving catalyst deactivation problem in the linear alkylbenzene (LAB) synthesis, the desilication treatment was found to be more effective than other approaches such as dealumination or metal/zeolite. The improved stability of the desilicated mordenite can be attributed to the enhanced diffusivity of oligomer by-products and coke precursors due to the enlarged mesopore size of the mordenite. In addition, 2-phenyl LAB isomer selectivity can be tuned by modification of the microporous structure of mordenite. The desilicated mordenite showed unprecedented stability and the 2-pheny LAB isomer yield up to 78% even if the octadiene-containing dodecene feed was used.

This paper reviews acid–base bifunctional catalysis and surface properties (morphology, composition, specific area, acidity/basicity, site density) on TiO 2 –ZrO 2 (abbreviated as TZ) mixed oxides. The phase change from crystalline single oxides (TiO 2 and ZrO 2 ) to amorphous TZ mixed oxide results in decreasing grain size and site density, increasing surface area, acid/base amount and strength, and better activity/selectivity. Different acid–base bifunctional mechanisms (concerted, go-together, stepwise) were proposed to interpret the reaction behavior of various reactions (esterification, dehydration, dehydrogenation, isomerization, dehydrocyclization) over the acid–base bifunctional TZ catalysts.

A low-temperature thermal chemical vapor deposition with an applied external magnetic field was used to grow carbon nanotubes (CNTs) on the bottom of a triode-type glass substrate. The Raman spectra reveal the graphitization of CNTs synthesized with different external magnetic fields. The magnetic field plays an important role in the growth of CNTs at low temperature (the ID/IG ratios decreased from 0.774 to 0.579, 0.426 and 0.305, for the samples with different magnetic forces of 0, 6.8, 12 and 13kG, respectively), which enhances the crystalline structure of CNTs and improves their field emission properties (the anode current increased from 0.01 to 180, 290 and 420μA with different applied external magnetic fields) for a triode-type field emission display application.

A variety of carbon-modified titania powders were prepared by impregnation method using a commercial available titania powder, Hombikat UV100, as matrix material while a range of alcohols from propanol to hexanol were used as precursors of carbon sources. Rising the carbon number of alcoholic precursor molecule, the modified titania showed increasing visible activities of NOx photodegradation. The catalyst modified with cyclohexanol exhibited the best activities of 62%, 62%, 59%, and 54% for the total NOx removal under UV, blue, green, and red light irradiation, respectively. The high activity with long wavelength irradiation suggested a good capability of photocatalysis in full visible light spectrum. Analysis of UV-visible spectrum indicated that carbon modification promoted visible light absorption and red shift in band gap. XPS spectroscopic analysis identified the existence of carbonate species (C=O), which increased with the increasing carbon number of precursor molecule. Photoluminescence spectra demonstrated that the carbonate species suppressed the recombination rate of electron-hole pair. As a result, a mechanism of visible-light-active photocatalyst was proposed according to the formation of carbonate species on carbon-modified TiO2.

High electrical conductive films were prepared by blending silver nanowires (AgNws) with hydrophilic and hydrophobic resins. 3-Aminopropyltriethoxysilane (APTES) silane was utilized to modify the surface of AgNws. The electrical properties. SEM morphological observation and weathering resistance of AgNws based conductive films were compared with those of silver nanoparticles (AgNps) conductive films. Due to the high aspect ratio of AgNws, the silver content in the conductive film could be reduced significantly by adding AgNws. Therefore, with increasing of binder ratio the conductive film possessed better mechanical stability. With the increasing of the silver content, the shielding effectiveness (SE) of electromagnetic interference (EMI) of the silver nanomaterial conductive film was increased. When the SE was under -20 dB (>99%) for all frequency ranging between 3 and 17 GHz, AgNws showed better efficiency in EMI shielding than AgNps, as a result of less requirement in content, which is of critical importance for the potential of silver based materials in enhancing electrical conductivity and EMI. (c) 2012 Elsevier B.V. All rights reserved.

This study develops a technique for enhancing the electrical conductivity and optical transmittance of transparent double-walled carbon nanotube (DWNT) film. Silver nanoparticles were modified with a NH(2)(CH(2))(2)SH self-assembled monolayer terminated by amino groups and subsequent surface condensation that reacted with functionalized DWNTs. Ag nanoparticles were grafted on the surface of the DWNTs. The low sheet resistance of the resulting thin conductive film on a polyethylene terephthalate (PET) substrate was due to the increased contact areas between DWNTs and work function by grafting Ag nanoparticles on the DWNT surfaces. Increasing the contact area between DWNTs and work function improved the conductivity of the DWNT-Ag thin films. The prepared DWNT-Ag thin films had a sheet resistance of 53.4 Ω/sq with 90.5% optical transmittance at a 550 nm wavelength. After treatment with HNO(3) and annealing at 150 °C for 30 min, a lower sheet resistance of 45.8 Ω/sq and a higher transmittance of 90.4% could be attained. The value of the DC conductivity to optical conductivity (σ(DC)/σ(OP)) ratio is 121.3.

This study uses a low temperature thermal chemical vapor deposition with an applied external magnetic field to grow carbon nanotubes (CNTs) on Ni/Ag-printed glass substrates. A mixture of C2H2 and H2 gas was used for the growth of the CNTs. A Ni catalyst layer was deposited on the Ag-printed glass substrate by pulse electroplating. Scanning electron micrographs as well as the presence of two sharp peaks at 1320cm−1 (D band) and 1590cm−1 (G band) in the Raman spectra indicate that the graphitized structure of CNTs synthesized under a magnetic field has higher quality (i.e., a D-band to G-band intensity ratio of 0.303) than CNTs synthesized without a magnetic field. Transmission electron micrographs show a fine Ni catalyst at the tip of the tube for CNTs synthesized under a magnetic field, exhibiting a CNT “tip-growth” model. The synthesis of CNTs in the presence of a magnetic field also generates better field emission properties and better lighting morphology than without a magnetic field.

n-Butyl lactate was synthesized with a good yield by the reaction between lactic acid and n-butanol over TiO2–ZrO2 catalysts. These catalysts had various Ti/(Ti+Zr) atomic ratios and were prepared by a co-precipitation method. XRD, n-butylamine/acetic acid adsorption, nitrogen adsorption, and SEM/EDS were used to characterize the oxides. The maximum activity was found for the catalyst with Ti/(Ti+Zr) ratio=0.75 (TZ31), which had smaller surface area and acid amount than the catalyst with Ti/(Ti+Zr) ratio=0.5. In general, turnover frequency (TOF) increased with increasing areal concentration of acid sites. The superiority performance of TZ31 (with a maximum product yield of 94.2%) was ascribed to the cooperation of TOF, acid site density, and specific surface area.

Osteopontin (OPN) is an extracellular matrix protein in hard tissues. The polymorphism in promoter region of OPN gene correlates to different gene expression and might implicate potential roles in tumor progression and metastasis. Immunohistochemistry (IHC) was utilized to detect the OPN expression in 58 oral squamous cell carcinoma (OSCC) tissues and adjacent normal oral mucosa. The differential OPN expression was further analyzed in relation to clinico-pathological features. Genomic DNA was obtained from isolated leukocytes of blood samples of OSCC patients (n = 100), and healthy individuals (n = 97) from Taiwan. The OPN gene polymorphism was analyzed by direct sequencing. Our result showed OPN expression was significantly higher in OSCC tissues than in the paired adjacent normal tissues (p < 0.01). The expression of OPN was significantly associated with nodal metastasis and the more advanced clinical stage (p < 0.05). More prevalent −156 insGG/insGG genotype and −443 T/T genotype was found in OSCC patients (p < 0.05). A significant difference in −443T/−156GG/−66T and −443C/−156G/−66T haplotypes between OSCC and controls (p < 0.05) was also noted. The OPN expression in tumor tissues significantly correlated with −156 insGG/insGG and −156 G/G + insGG/G genotypes (p < 0.05). The conclusion is tissue OPN expression correlates to OSCC progression. −156 insGG/insGG genotype is associated with OSCC susceptibility and higher OPN expression.