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Background and Objectives: acute kidney injury (AKI), formerly called acute renal failure (ARF), is commonly defined as an abrupt decline in renal function, clinically manifesting as a reversible acute increase in nitrogen waste products—measured by blood urea nitrogen (BUN) and serum creatinine levels—over the course of hours to weeks. AKI occurs in about 20% of all hospitalized patients and is more common in the elderly. Therefore, it is necessary to prevent the occurrence of AKI, and to detect and treat early, since it is known that a prolonged period of kidney injury increases cardiovascular complications and the risk of death. Despite advances in modern medicine, there are no consistent treatment strategies for preventing the progression to chronic kidney disease. Through many studies, the safety and efficacy of natural products have been proven, and based on this, the time and cost required for new drug development can be reduced. In addition, research results on natural products are highly anticipated in the prevention and treatment of various diseases. In relation to AKI, many papers have reported that many natural products can prevent and treat AKI. Conclusions: in this paper, the results of studies on natural products related to AKI were found and summarized, and the mechanism by which the efficacy of AKI was demonstrated was reviewed. Many natural products show that AKI can be prevented and treated, suggesting that these natural products can help to develop new drugs. In addition, we may be helpful to elucidate additional mechanisms and meta-analysis in future natural product studies.

Chalcone isomerase (CHI) is a key enzyme in flavonoid biosynthesis. In plants, CHIs occur in multigene families, and they are divided into four types, types I–IV. Type I and II CHIs are bona fide CHIs with CHI activity, and type III and IV CHIs are non-catalytic members with different functions. Rice contains seven CHI family genes (OsCHIs). Molecular analysis suggested that OsCHI3 is a type I CHI, and the other OsCHIs were classified into types III and IV. To elucidate their biochemical functions, OsCHI1, OsCHI3, OsCHI6, and OsCHI7 were expressed in Escherichia coli, and the recombinant OsCHI proteins were purified. An activity assay of recombinant OsCHIs showed that OsCHI3 catalyzed the isomerization of naringenin chalcone and isoliquiritigenin, whereas the other recombinant OsCHIs had no CHI activity. OsCHI3 also exhibited a strong preference to naringenin chalcone compared to isoliquiritigenin, which agrees well with the catalytic properties of type I CHIs. These results ascertain OsCHI3 to be a bona fide CHI in rice. OsCHI3 and the other OsCHIs were expressed constitutively throughout the rice growth period and different tissues. OsCHI3 expression was induced immediately in response to ultra-violet (UV) stress, suggesting its involvement in the biosynthesis of sakuranetin, a flavonoid phytoalexin in rice.

Objective Renal ischemia/reperfusion (I/R) injury is characterized by the acute deterioration of renal function during ischemia and renal inflammation. Cassia tora has various effects, including antioxidant, antidiabetic, and hypolipidemic properties. In the present study, we investigated whether C tora has a renoprotective effect on I/R-induced acute kidney injury in rats. Methods We fed Sprague-Dawley rats either C tora (100 mg/kg/d) or saline. One week later, ischemia was induced by bilateral renal pedicle occlusion for 30 minutes, followed by reperfusion. Rats were randomized into 3 major groups, which were treated as follows: 1. the sham operation group; 2. the I/R group; and 3. the I/R-C tora group. Results Compared to the sham group, the I/R group had higher levels of blood urea nitrogen and serum creatinine in serum and lower expression of catalase, superoxide dismutase, glutathione peroxidase, antioxidant, and nitric oxide. Compared to the I/R group, the I/R-C tora group had higher expression of catalase, superoxide dismutase, glutathione peroxidase, antioxidant, and nitric oxide, as well as lower levels of blood urea nitrogen and creatinine in serum. Conclusions These results suggest that C tora has significant therapeutic effects in ischemic renal injury.

Jung Seok Kim,1,* Min Woo Kim,1,* Seong Jae Kang,1,* Hwa Yeon Jeong,1 Sang Il Park,1 Yeon Kyung Lee,1 Hong Sung Kim,2 Keun Sik Kim,3 Yong Serk Park1 1Department of Biomedical Laboratory Science, Yonsei University, Wonju, Republic of Korea; 2Department of Biomedical Laboratory Science, Korea Nazarene University, Cheonan, Republic of Korea; 3Department of Biomedical Laboratory Science, Konyang University, Daejeon, Republic of Korea *These authors contributed equally to this work Background: Efficient target-specific siRNA delivery has always been a primary concern in the field of siRNA clinical application. Purpose: In this study, four different types of anti-epidermal growth factor receptor (EGFR) antibody-conjugated immunonanoparticles were prepared and tested for cancer cell-targeted therapeutic siRNA delivery. Materials and methods: The prepared nanoparticles encapsulating siRNAs were characterized by gel retardation and particle analysis using a Zetasizer. In vitro transfection and reduction of target genes, vimentin and JAK3, were determined using quantitative reverse transcription polymerase chain reaction. In vivo tumor targeting and antitumoral efficacies of the nanoparticles were evaluated in mice carrying tumors. Results: Among these immunonanoparticles, anti-EGFR immunolipoplexes and immunoviroplexes exhibited remarkable cell binding and siRNA delivery to EGFR-expressing tumor cells compared to immunoliposomes and immunovirosomes. Especially, the anti-EGFR immunoviroplexes exhibited the most efficient siRNA transfection to target tumor cells. Therefore, antitumoral vimentin and Janus kinase-3 siRNAs were loaded in the anti-EGFR immunolipoplexes and immunoviroplexes, which were tested in mice carrying SK-OV-3 tumor xenografts. In fact, the therapeutic siRNAs were efficiently delivered to the tumor tissues by both delivery vehicles, resulting in significant inhibition of tumor growth. Moreover, administration of doxorubicin in combination with anti-EGFR immunoviroplexes resulted in remarkable and synergistic tumor growth inhibition. Conclusion: This study provides experimental proof that cancer cell-targeted immunoviroplexes are an efficient siRNA delivery system for cancer therapy. Moreover, this study also suggests that a combination of conventional chemotherapy and tumor-directed anticancer siRNA therapy would be a better modality for cancer treatment. Keywords: EGFR, siRNA delivery, anti-EGFR immunonanoparticles, anti-EGFR immunoviroplexes, combinatorial therapy

Objectives The purpose of the study was to investigate the protective effect of the Curcuma longa L. extract (CLE) and its curcuminoids against blue light-induced cytotoxicity in human retinal pigment epithelial (RPE) cells laded with A2E. A2E has been concerned in age-related macular degeneration (AMD). Methods To perform this study, A2E-accumulated ARPE-19 cells were exposed to blue light to induce cytotoxicity. The cytotoxicity and apoptotic gene expression levels were evaluated using a lactate dehydrogenase (LDH) assay and real-time PCR analysis, respectively. Key findings Curcuma longa L. extract was found to exert a protective effect in a dose-dependent manner. At a concentration of 15 μm, curcumin, demethoxycurcumin and bisdemethoxycurcumin exerted significant protective effects against blue light-induced cytotoxicity. Treatment with CLE and curcuminoids meaningfully reduced the mRNA levels of c-Abl and p53, which was known to be augmented in apoptotic RPE cells. Demethoxycurcumin and bisdemethoxycurcumin were found to inhibit p38 expression, which is increased in blue light-irradiated A2E-accumulated RPE cells. Conclusions Curcuma longa L. extract and its curcuminoids provided significant protection against photooxidative damage and apoptosis in the RPE cells. Our results suggest that curcuminoids may show potential in the treatment of AMD.

Blue light has high photochemical energy and induces cell apoptosis in retinal pigment epithelial cells. Due to its phototoxicity, retinal hazard by blue light stimulation has been well demonstrated using high intensity light sources. However, it has not been studied whether blue light in the displays, emitting low intensity light, such as those used in today's smartphones, monitors, and TVs, also causes apoptosis in retinal pigment epithelial cells. We attempted to examine the blue light effect on human adult retinal epithelial cells using display devices with different blue light wavelength ranges, the peaks of which specifically appear at 449 nm, 458 nm, and 470 nm. When blue light was illuminated on A2E-loaded ARPE-19 cells using these displays, the display with a blue light peak at a shorter wavelength resulted in an increased production of reactive oxygen species (ROS). Moreover, the reduction of cell viability and induction of caspase-3/7 activity were more evident in A2E-loaded ARPE-19 cells after illumination by the display with a blue light peak at a shorter wavelength, especially at 449 nm. Additionally, white light was tested to examine the effect of blue light in a mixed color illumination with red and green lights. Consistent with the results obtained using only blue light, white light illuminated by display devices with a blue light peak at a shorter wavelength also triggered increased cell death and apoptosis compared to that illuminated by display devices with a blue light peak at longer wavelength. These results show that even at the low intensity utilized in the display devices, blue light can induce ROS production and apoptosis in retinal cells. Our results also suggest that the blue light hazard of display devices might be highly reduced if the display devices contain less short wavelength blue light.

A2E-laden ARPE-19 cells were exposed to a blue light to induce cytotoxicity, in order to investigate the protective effects of various tinted ophthalmic lenses against photo-induced cytotoxicity in human retinal pigment epithelial (RPE) cells laden with A2E, known to be among the etiologies of age-related macular degeneration (AMD). Different-colored tinted lenses with varying levels of tint and different filtering characteristics, such as polarized, blue-cut, and photochromatic lenses, were placed over the cells, and the protective efficacies thereof were evaluated by lactate dehydrogenase assay. When tinted lenses were placed over ARPE-19 cells, there were different reductions in cytotoxicity according to the colors and tint levels. The level of protection afforded by brown-tinted lenses was 6.9, 36.1, and 49% with a tint level of 15, 50, and 80%, respectively. For gray-tinted lenses, the protective effect was 16.3, 35, and 43.4% for the corresponding degree of tint, respectively. In the case of blue-tinted lenses, a protective effect of 20% was observed with 80% tinted lenses, but 15 and 50% tinted lenses provided no significant protection. In addition, photochromic lenses showed a protective effect but blue-cut lenses and polarized lenses provided no significant protection. Tinted lenses significantly reduced cytotoxicity in RPE cells irradiated with blue light. The protection was more efficient in lenses with a brown or gray tint than in blue-tinted lenses. Tinted glasses may provide significant protection against potential blue-light-induced photochemical and photo-oxidative damage in RPE cells.

A non-destructive metrology technique for critical dimension of Fin structure is important for better device characterization and development for improving yield. Due to extremely small dimension with high complexity in FinFET a new metrology solution needs to be evaluated. In-line atomic resolution profiler was performed to provide a suitable metrology for oxide recess metrology in Fin process. The technique could measure accurately the height and CD of Fin structures, which has the space with of 25 nm and the height of 60 nm. The uniformity of recess height could be measured, which could be interpreted by loading effect of etch process. High long term repeatability of the technique was achieved for process monitoring purpose.

BACKGROUND The effective delivery of therapeutic genes to target cells has been a fundamental goal in cancer gene therapy because of its advantages with respect to both safety and transfection efficiency. In the present, study we describe a tumor-directed gene delivery system that demonstrates remarkable efficacy in gene delivery and minimizes the off-target effects of gene transfection. METHODS The system consists of a well-verified cationic O,O'-dimyristyl-N-lysyl glutamate (DMKE), Sendai virus fusion (F) protein and hemagglutinin-neuraminidase (HN) protein, referred to as cationic Sendai F/HN virosomes. To achieve tumor-specific recognition, anti-epidermal growth factor (EGF) receptor antibody was coupled to the surface of the virosomes containing interleukin-12 (IL-12) and/or salmosin genes that have potent anti-angiogenetic functions. RESULTS Among the virosomal formulations, the anti-EGF receptor (EGFR) viroplexes, prepared via complexation of plasmid DNA (pDNA) with cationic DMKE lipid, exhibited more efficient gene transfection to tumor cells over-expressing EGF receptors compared to the neutrally-charged anti-EGFR virosomes encapsulating pDNA. In addition, the anti-EGFR viroplexes with IL-12 and salmosin genes exhibited the most effective therapeutic efficacy in a mouse tumor model. Especially when combined with doxorubicin, transfection of the two genes via the anti-EGFR viroplexes exhibited an enhanced inhibitory effect on tumor growth and metastasis in lungs. CONCLUSIONS The results of the present study suggest that anti-EGFR viroplexes can be utilized as an effective strategy for tumor-directed gene delivery. Copyright © 2016 John Wiley & Sons, Ltd.

A field test of a 70 ㎾ heat pump system with flue gas heat recovery was performed by an experiment at theKorea Institute of Energy Research. The flue gas is exhausted from a 320 RT absorption chiller-heater in the heating season.Using this flue gas, source water of the heat pump is heated by a condensed-type heat exchanger in the chimney. Theoperating characteristics of the heat recovery heat pump system were analyzed. Based on the results of the experiments, operating maps were obtained, and an optimum operating range is suggested, in which the return and heat source watertemperature are 51 ℃ and 31 ℃ , respectively. Additionally, economic analysis of this system was conducted and about 50%energy cost savings can be expected in the heating season. Key words Condensing heat recovery(응축열회수), Flue gas(배가스), Heat recovery system(열회수 시스템), Latent heat(잠열), Condensation(응축)†Corresponding author, E-mail: yslee@kier.re.kr 기호설명COP H ： 난방성능계수 Q cond ： 응축(난방)열량 [ ㎾ ] Q evap ： 증발열량 [ ㎾ ]

Single crystal silicon wafers are the fundamental elements of semiconductor manufacturing industry. The wafers produced by Czochralski (CZ) process are very high quality single crystalline materials with known defects that are formed during the crystal growth or modified by further processing. While defects can be unfavorable for yield for some manufactured electrical devices, a group of defects like oxide precipitates can have both positive and negative impacts on the final device. The spatial distribution of these defects may be found by scattering techniques. However, due to limitations of scattering (i.e. light wavelength), many crystal defects are either poorly classified or not detected. Therefore a high throughput and accurate characterization of their shape and dimension is essential for reviewing the defects and proper classification. While scanning electron microscopy (SEM) can provide high resolution twodimensional images, atomic force microscopy (AFM) is essential for obtaining three-dimensional information of the defects of interest (DOI) as it is known to provide the highest vertical resolution among all techniques [1]. However AFM’s low throughput, limited tip life, and laborious efforts for locating the DOI have been the limitations of this technique for defect review for 300 mm wafers. To address these limitations of AFM, automatic defect review AFM has been introduced recently [2], and is utilized in this work for studying DOI on 300 mm silicon wafer. In this work, we carefully etched a 300 mm silicon wafer with a gaseous acid in a reducing atmosphere at a temperature and for a sufficient duration to decorate and grow the crystal defects to a size capable of being detected as light scattering defects [3]. The etched defects form a shallow structure and their distribution and relative size are inspected by laser light scattering (LLS). However, several groups of defects couldn’t be properly sized by the LLS due to the very shallow depth and low light scattering. Likewise, SEM cannot be used effectively for post-inspection defect review and classification of these very shallow types of defects. To verify and obtain accurate shape and three-dimensional information of those defects, automatic defect review AFM (ADR AFM) is utilized for accurate locating and imaging of DOI. In ADR AFM, non-contact mode imaging is used for non-destructive characterization and preserving tip sharpness for data repeatability and reproducibility. Locating DOI and imaging are performed automatically with a throughput of many defects per hour. Topography images of DOI has been collected and compared with SEM images. The ADR AFM has been shown as a non-destructive metrology tool for defect review and obtaining three-dimensional topography information.

Objectives: This study was conducted in order to examine the relationship between heavy metal concentrations in the soil and the level of heavy metals in the blood or urine of 216 local residents living near abandoned metal mines. Methods: Residents around abandoned metal mines were interviewed about their dietary habits, including seafood consumption, medical history, cigarette smoking, and drug history. Metal concentrations in the soil were determined by atomic absorption spectrophotometer (AA-7000, Shimadzu, Japan). Lead (Pb) and cadmium (Cd) contents in the blood or urine were analyzed by GF-AAS (AA-6800, Shimadzu). Mercury (Hg) contents in the blood were determined by means of a mercury analyzer (SP-3DS, NIC). Arsenic (As) content in the soil and urine were measured by a HG-AAS (hydride vapor generation-atomic absorption spectrophotometer). Results: The heavy metal concentrations in the soil showed a log normal distribution and the geometric means of the four villages were 8.61 mg/kg for Pb, 0.19 mg/kg for Cd, 1.81 mg/kg for As and 0.035 mg/kg for Hg. The heavy metal levels of the 216 local residents showed a regular distribution for Pb, Cd, Hg in the blood and As in the urine. The arithmetic means were3.37 µg/dl for Pb, 3.07 µg/l for Cd and 2.32 µg/l for Hg, 10.41 µg/l for As, respectively. Conclusions: As a result of multi-variate analysis for the affecting factors on the bodily heavy metal concentrations, gender and concentration in the soil (each, p

We fabricated hydrogenated microcrystalline silicon (μc-Si:H) solar cells on SnO 2 coated glass using a seed layer insertion technique. Since rich hydrogen atoms from the μc-Si:H deposition process degrade the SnO 2 layer, we applied p-type hydrogenated amorphous silicon (p-a-Si:H) as a window layer. To grow the μc-Si:H layer on the p-a-Si:H window layer, we developed a seed layer insertion method. We inserted the seed layer between the p-a-Si:H layer and intrinsic bulk μc-Si:H. This seed layer consists of a thin hydrogen diluted silicon buffer layer and a naturally hydrogen profiled layer. We compared the characteristics of solar cells with and without the seed layer. When the seed layer was not applied, the fabricated cell showed the characteristics of a-Si:H solar cell whose spectral response was in a range of 400–800 nm. Using the seed layer, we achieved a μc-Si:H solar cell with performance of V oc =0.535 V, J sc =16.0 mA/cm 2 , FF=0.667, and conversion efficiency=5.7% without any back reflector. The spectral response was in the range of 400–1100 nm. Also, the fabricated device has little substrate dependence, because a-Si:H has weaker substrate selectivity than μc-Si:H.

Recently, heavy metals contamination of the agricultural soil and crops surrounding mining areas has been identified as one of the most serious environmental problems in South Korea. The Ministry of the Environment in Korea conducted a Preliminary National Environmental Health Survey (PNEHS) in abandoned metal mines in 2007. The priority for a subsequent detailed examination was ranked from the results of PNEHS. The studied mine which was ranked as being of the highest priority is located in the midwestern part of Korea and was operated from 1911 to 1985. In this study, the contamination levels of the heavy metals in the abandoned metal mine were investigated. From the results, the average daily dose (ADD), target hazard quotient (THQ) and target cancer risk of the heavy metals were evaluated. The concentration of arsenic (As) in all of the tailings from the mine was higher than its countermeasure standard of Korea. In particular, the highest concentration of As, 330 ㎎/㎏, was up to 15 times higher than its countermeasure standard. The average concentration of As in agricultural soils was higher than the warning standard of Korea, and higher than its countermeasure standard at six sites. The average concentrations of the analyzed heavy metals in agricultural soil were below the warning standard, but concentrations of cadmium (Cd) and lead (Pb) at 4 sites were higher than its warning standard. The average concentration of As in surface water exceeded the warning standard of Korea. The value of the THQ of As for the tailings was higher than the health protection standard 1. The value of THQ of As for the farmlands was lower than the standard, while the hazard index (HI) of As was higher than the standard. The value of target cancer risk (TCR) of As, 6.44 × 10?⁴, were higher than the health protection standard of a lifetime risk for TCR at 1 × 10??. This suggests that the residents around the metal mines are exposed to As pollution with a carcinogenic risk.

This paper describes materials and mechanics aspects of bending in systems consisting of ribbons and bars of single crystalline silicon supported by sheets of plastic. The combined experimental and theoretical results provide an understanding for the essential behaviors and for mechanisms associated with layouts that achieve maximum bendability. Examples of highly bendable silicon devices on plastic illustrate some of these concepts. Although the studies presented here focus on ribbons and bars of silicon, the same basic considerations apply to other implementations of inorganic materials on plastic substrates, ranging from amorphous or polycrystalline thin films, to collections of nanowires and nanoparticles. The contents are, as a result, relevant to the growing community of researchers interested in the use of inorganic materials in flexible electronics.

This paper describes experimental and theoretical studies of the mechanics of free-standing nanoribbons and membranes of single-crystalline silicon transfer printed onto patterned dielectric layers. The results show that analytical descriptions of the mechanics agree well with experimental data, and they explicitly reveal how the geometry of dielectric layers (i.e., the width and depth of the features of relief) and the silicon (i.e., the thickness and widths of the ribbons) affect mechanical bowing (i.e., ‘‘sagging’’) in the suspended regions of the silicon. This system is of practical importance in the use of semiconductor nanomaterials for electronic devices, because incomplete sagging near defects in gate dielectrics provides a level of robustness against electrical shorting in those regions which exceeds that associated with conventional deposition techniques for thin films. Fieldeffect transistors formedusingsilicon nanoribbonstransferred onto arangeofultrathingate dielectrics, includingpatterned epoxy, organic self-assembled monolayers, and HfO2, demonstrate these concepts.

We have developed p–i–n/p–i–n-type protocrystalline silicon (pc-Si:H) multilayer tandem solar cells. The purpose of this work is to make a thin film silicon solar cell with low degradation by combining the virtues of a pc-Si:H multilayer and tandem structure. The usefulness of the pc-Si:H multilayer as a low degradation top and bottom cell was confirmed when we achieved a low degradation ratio of 10.0%. Notably, this tandem cell stabilized rapidly, within 1 h. Nanocrystalline silicon (nc-Si) grains embedded in a pc-Si:H multilayer were detected with the aid of a planer transmission electron microscope. The isolated nc-Si grains may suppress the photocreation of dangling bonds due to non-radiative recombination in an a-Si:H matrix. Because of these embedded nc-Si grains, the pc-Si:H multilayer has a fast and high light-induced metastability.

We investigate the hydrogen doping effect on polycrystalline ZnO thin films prepared by the photoassisted metalorganic chemical vapor deposition technique. In situ post-deposition hydrogen doping was performed using mercury-sensitized photodecomposition of hydrogen gas. From Fourier transform infrared spectra, we observe small changes in O–H bond-stretching local vibrational modes as a result of hydrogen doping. The photoluminescence measurements reveal that intentional hydrogen doping significantly suppresses nonradiative recombination centers in the ZnO films. The undoped ZnO film reveals a heavily n-type as-grown conductivity due to the high hydrogen content, but it is unstable in a humid air atmosphere. However, the electrical stability is significantly improved as a result of hydrogen doping.

Scanning capacitance microscopy (SCM) has been gaining attention for its capability to measure local electrical properties in doping profile, oxide thickness, trapped charges and charge dynamics. In many cases, stray capacitance produced by different samples and measurement conditions affects the resonance frequency of a capacitance sensor. The applications of conventional SCM are critically limited by the fixed operating frequency and lack of tunability in its SCM sensor. In order to widen SCM application to various samples, we have developed a novel SCM sensor with variable operating frequency. By performing variable frequency sweep over the band of 160 MHz, the SCM sensor is tuned to select the best and optimized resonance frequency and quality factor for each sample measurement. The fundamental advantage of the new variable frequency SCM sensor was demonstrated in the SCM imaging of silicon oxide nano-crystals. Typical sensitivity of the variable frequency SCM sensor was found to be 10−19 F/V.

Emission of methane and nitrous oxide affected by nitrogen fertilizer materials were measured simultaneously in rice paddy fields under flooding and intermittent irrigation in 2000. Studies focused on mitigating emission from rice paddy fields are summarized and the possibilities and limits applied to world`s rice cultivation are discussed. The mitigation options are water management, soil amendments, organic matter management, different tillage, rotation, and cultivar selection. Altering water management, in particular promoting midseason aeration by short-term drainage, is one of the most promising strategies, although these practices may be limited to the rice paddy fields where the irrigation system is well prepared. The test site was divided into two water managements: a continuously flooded plot which was maintained flooded by constant irrigation from May to September, and an intermittently drained plot in which short-term (20days) draining practices were performed one times during the flooding period. By total emission of GHGs converted by global warming potential (GWP), flooding plots were higher 170208% than interimittent irrigation plots. For emission of GHGs in fertilizer materials, it was high in the order of Swine slurry>Urea+Rice straw>Urea>LCU. Basing on GHGs emission of urea fertilization under flooding as baseline GWP of urea fertilization and Latex-coated urea under intermittent irrigation showed lower GHGs emission by 41.4% and 55.8 respectively. In this case fertilizer use efficiency (kg unhulled rice/ of applied N) were 18.220.2 and 18.719.0 and 9.3 and 5.86.6 for Swine slurry and LCU and Urea+Rice straw and Urea in the continuously flooded and intermittently drained plot.

The multi-stage fluidized bed can be used to preheat the combustion air by recovering the waste heat from the exhaust gas from industrial furnaces. The dilute-phase fluidized bed may be formed to exclude the excessive pressure drop across the multi-stage fluidized bed. But, in this case, the solid particles do not reach to the thermal equilibrium due to relatively short residence time in each layer of fluidized bed. In this study, a theoretical analysis on the dilute phase multistage fluidized bed heat exchanger was performed. A parameter related to the degree of thermal equilibrium between gas and solid particles at the dilute-phase fluidized beds was derived. Using this parameter, a relatively simple expression was obtained for the thermal efficiencies of the multi-stage fluidized bed heat exchanger and air preheater. Copyright © 2001 John Wiley & Sons, Ltd.

We have investigated domain structure and dynamics of a triglycine sulfate (TGS) single crystal with a dynamic contact mode electrostatic force microscope (DC-EFM), which is operated in contact mode. DC-EFM can overcome a problem in conventional noncontact EFM measurement. The temperature dependence of surface charge density was measured by a nulling technique. We also investigated local domain switching behaviors of TGS single crystal and PZT thin film. Complex pattern was written on a PZT thin film by the polarization reversal. A writing capability such as a writing speed and voltage dependence in PZT film has been studied by DC-EFM.

A dynamic contact mode operation of electrostatic-force microscopy (EFM) with an ac modulation has been developed and used to investigate the domain strucutre and dynamics of a triglycine sulfate single crystal. Well-separated topographic and domain contrast images have been obtained by detecting the force instead of the force gradient in the dynamic contact mode operation of EFM. Surface charge density and the anisotropic domain wall thickness have been measured. The evolution of domains embedded in an oppositely polarized larger domain indicates the existence of a significant interaction between domains of the same polarity.

Amorphous silicon (a-Si:H) solar cell fabricated on zinc oxide (ZnO) has poor fill factor (FF) resulting from a high resistive contact between ZnO and p-type amorphous silicon carbide (p-a-SiC:H) films. This is due to the existence of a wide depletion region in the p-a-SiC:H adjacent to the ZnO/p-a-SiC:H interface. To overcome this contact problem, an amorphous tungsten oxide (WO 3 ) layer was inserted between ZnO and p-a-SiC:H. It was found that the insertion of the WO 3 layer improves the cell performance by reducing series resistance. Since this layer has higher optical band-gap (3.35 eV) than a-SiC:H (2.1 eV), there was no change of current density in short wavelength regions. A radio-frequency magnetron sputtering apparatus was used to deposit ZnO:Al on glass. The structure of the cells was ZnO:Al (800 nm)/n-a-WO 3 (4 nm)/p-a-SiC:H (10 nm)/i-a-Si:H (270 nm)/n-a-Si:H (30 nm)/Al (100 nm). As a result of the WO 3 insertion, the efficiency of the solar cell enhanced from 6.89% to 7.45%.

Flexible and lightweight amorphous silicon (a-Si:H) based thin-film solar cells on surface-textured glass-fabric reinforced inorganic-organic hybrid materials (hybrimer) composite films are developed in a superstrate configuration. The flexible and transparent film for the substrate was fabricated by impregnation and lamination of a woven glass-fabric with an epoxy-oligosiloxane based hybrimer on glass used as a temporary substrate. The epoxy hybrimer film showed high optical transparency of more than ∼90% for wavelengths above 500nm and light scattering property. In order to improve light trapping, the surface texture of the film was replicated from a master texture of Asahi U-type glass by nanoimprint lithography. The fabricated cell was a single junction structure of ZnO:Al/p-μc-Si:H/p-a-SiC:H/i-a-Si:H/n-μc-Si:H/Al on the flexible film, and the thickness of i layer is ∼300 nm. The flexible a-Si:H solar cell on surface-textured expoxy hybrimer film showed an conversion efficiency of 6.4%.

Flexible and lightweight amorphous silicon (a-Si:H) based thin-film solar cells on glass-fabric reinforced inorganic-organic hybrid materials (hybrimer) composite films are newly proposed in the paper. They were developed in a superstrate configuration where light is absorbed in a-Si:H layers after passing through the transparent film. The flexible and transparent film for the substrate was fabricated using glass-fabric placement and a hybrimer coating on glass used as a temporary substrate. It was cured under a high pressure. The flexible film on the glass showed optical transmittances of more than ∼87% for wavelengths above 550nm and moderate light-scattering properties. Flexible p-i-n a-Si:H solar cells were developed on glass-fiber reinforced hybrimer composite film in the superstrate configuration using the glass as a temporary substrate during the deposition process. The flexible a-Si:H single junction solar cells show an efficiency of 5.3% with V oc =0.86 V, J sc =10.6 mA/cm2 and FF=58%.

The enhancement of optical transmittance at the air/glass interface of amorphous silicon thin film solar cells was shown by application of a nanoporous polymethyl methacrylate (PMMA) antireflection (AR) coating. The PMMA coating was prepared by spin coating of PMMA solution in chloroform in the presence of a small amount of nonane. Because of the difference of the vapor pressure of chloroform and nonane, phase separated structure formed after complete evaporation of both of them during spin coating process. The Corning 1737 glass with the AR coating has high transmittance near 95% from 450-1100nm wavelengths. The amorphous silicon solar cells with the nanoporous PMMA AR coating realize an improvement in quantum efficiency (QE) up to 4% in 450-650nm spectral regions.

Charge trapping induced by hot carriers in a metal–oxide–semiconductor capacitor was studied with a scanning capacitance microscope (SCM). The local charge trapping/detrapping and the readout of the trapped charge in SiO2 was performed using a SCM combined with an atomic force microscope. When applying a voltage between the conductive probe tip and the p-type silicon substrate, hot carriers injected from silicon substrate into the SiO2 generated a positive trapped charge in the 10-nm-thick SiO2 layer. The resulting shift in capacitance–voltage (C–V) curves due to the locally trapped charge was measured by the high-frequency C–V measurement. For an application to the ultrahigh density data storage field, we investigated how the charge trapping and detrapping characteristics depend on the writing speed and bias voltage.

The high natural abundance of silicon, together with its excellent reliability and good efficiency in solar cells, suggest its continued use in production of solar energy, on massive scales, for the foreseeable future. Although organics, nanocrystals, nanowires and other new materials hold significant promise, many opportunities continue to exist for research into unconventional means of exploiting silicon in advanced photovoltaic systems. Here, we describe modules that use large-scale arrays of silicon solar microcells created from bulk wafers and integrated in diverse spatial layouts on foreign substrates by transfer printing. The resulting devices can offer useful features, including high degrees of mechanical flexibility, user-definable transparency and ultrathin-form-factor microconcentrator designs. Detailed studies of the processes for creating and manipulating such microcells, together with theoretical and experimental investigations of the electrical, mechanical and optical characteristics of several types of module that incorporate them, illuminate the key aspects.

AuCl 3 efficiently catalyzes cyclization of tert -butyl allenoates into γ-butenolides. Advantage of directly using allenic ester precursor instead of corresponding acid is demonstrated in the synthesis of a variety of 2,4-disubstituted butenolides. A low catalyst loading and mild reaction condition makes this process an attractive alternative over conventional methods using strong Lewis acids.

We have developed a simple tapping mode in atomic force microscopy using a capacitive electrostatic force. In this technique, the probe‐to‐sample distance is modulated by the capacitive force between tip and sample induced by a sinusoidal bias applied to the conductive probe instead of a conventional mechanical vibration. The electrostatic force versus distance curve of the probe indicates that it is necessary to use a rather stiff cantilever to prevent the snapping of the tip into the surface due to the adhesive force at the surface. We have succeeded in obtaining topographic images of a conductive surface as well as a soft polystyrene sample with a low tracking and lateral force through this method.

A thermally evaporated molybdenum oxide (MoO3) film was used as a window layer of a hydrogenated amorphous silicon (a-Si:H) solar cell instead of the conventional p-type hydrogenated amorphous silicon carbide (p-a-SiC:H) film. The short circuit current density (JSC) and fill factor were increased due to the wide optical band gap and high conductivity of the MoO3 film. As a result, the conversion efficiency of the fabricated MoO3 solar cell was increased to 6.21% compared to the typical a-Si:H solar cell (5.97%).

We present scanning tunneling microscope images that confirm a 1 3 ML adatom model for the Ga induced 3 × 3 reconstruction of Si(111). We have also identified the bonding site of the Ga adatoms in this structure as the threefold site above second layer Si atoms. The images also show the presence of defects that arise from Si adatom replacement.

SUMMARY We have used scanning tunnelling microscopy (STM) to study changes in the structure of the Si(111) surface induced by deposition of the group III metals In and Ga. For both metals, several different ordered reconstructions are seen as a function of coverage. The STM images provide new structural information on each of these reconstructions. With In metal deposition, we have seen the surface reconstructions √3×, √3, √31× √31, √7×√3 and 4×1 as the coverage increases. In the case of Ga on Si(111), we have studied structures that exist up to 0·7 ML. At 1/3 ML, there is a √3×√3 structure identical to that of In. Above 0·3 ML there is a different phase that may correspond to the (6·3times6·3) RHEED pattern reported in this coverage range. This surface tends to grow as triangular islands at higher coverages.

We have performed electron tunneling measurements on thin niobium films made by electron beam evaporation. From these data tunneling ${\ensuremath{\alpha}}^{2}F(\ensuremath{\omega})$, the electron-phonon spectral function has been generated as a function of thickness from 900 \AA{} down to 30 \AA{}. Despite the onset of some phonon mode softening as sample thickness gets thinner, the electron-photon coupling constant $\ensuremath{\lambda}$ decreases from 0.9 at 900 \AA{} to 0.74 at 30 \AA{} consistent with the drop in the transition temperature.

Images of graphite have been recorded with a scanning tunneling microscope operating in air at ambient pressure. The results, which are in agreement with theory and previous experiments in vacuum, confirm that with a surface such as graphite the tunneling microscopy in air can be used to examine the geometry of the surface with a resolution that is less than 2 A.

The structure of different reconstructions of Sn on Si(111) has been studied by scanning tunneling microscopy. For less than a monolayer (ML) of Sn, three reconstructions are seen with 7×7, 7/8 × 7/8 , and 2 7/8 ×2 7/8 periodicities. The 7×7 structure is similar to that of the clean surface. The 7/8 × 7/8 phase is a (1)/(3) ML array of adatoms similar to that of Al, Ga, or In on Si(111). The 2 7/8 ×2 7/8 structure is twofold symmetric with three possible orientations on the surface giving the threefold symmetry apparent in the low‐energy electron diffraction pattern. All three surface phases coexist above 0.3 ML.

The behavior of gallium on the Si(100) surface has been studied with scanning tunneling microscopy at low metal coverages. The Ga atoms are more mobile on Si(100) than on Si(111) under the same conditions. At less than 0.1 monolayer, the Ga atoms line up in rows parallel to the Si dimerization direction with a two unit cell periodicity. At higher metal densities, these rows are organized into areas of 3×2 two‐dimensional order. The relevance of these results to studies of the initial stages of growth of GaAs on Si is discussed.

The scanning tunneling microscope(STM) has the capability of mapping the topography of a surface with unprecedented resolution in both vertical and lateral directions. STM has been used to obtain real space images of individual atoms on a surface. In this paper we review the principles and technical aspects of STM, and give some examples of its applications both in air and vacuum. These include images of graphite, silicon, and indium on silicon. Several techniques of digital image processing developed to facilitate the analysis of STM data are also described.

The simple metal indium is known to induce different reconstructions of the silicon (111) surface in the range of metal coverages below one monolayer (1 ML). We have studied both the $\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}$ and the 4\ifmmode\times\else\texttimes\fi{}1 reconstructions with scanning tunneling microscopy. Images of the $\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}$ surface are consistent with $\frac{1}{3}$ ML of In adatoms resting in threefold sites. The higher-coverage 4\ifmmode\times\else\texttimes\fi{}1 surface consists of large reconstructed terraces often bounded by abrupt, stepped edges. Growth of flat metal islands is also seen around 1 ML.