Effect of p-μc-Si1−xOx:H layer on performance of hetero-junction microcrystalline silicon solar cells under light concentration

Preparation of p-type hydrogenated microcrystalline silicon oxide thin films (p-μc-Si_1−xO_x:H) by 13.56 MHz RF-PECVD method for use as a p-layer of hetero-junction μc-Si:H solar cells is presented. We investigated effects of wide-gap p-μc-Si_1−xO_x:H layer on the performance of hetero-junction μc-Si:H solar cells under various light intensity. We observed that a wide-gap p-μc-Si_1−xO_x:H was effective in improving the open-circuit voltage (V_oc) of the solar cells. We also confirmed that the V_oc logarithmically increased with increasing light intensity, and the enhancement of V_oc became larger with increasing band gap of p-layer. These results indicate that wide-gap p-μc-Si_1−xO_x:H is a promising material for use as window layer in hetero-junction μc-Si:H solar cells.     

A relaxation algorithm with a probabilistic guarantee for robust deviation optimization

Three measures of robustness (absolute robustness, deviation robustness and relative robustness), whose choice depends on the goals of the decision maker, have been proposed for uncertain optimization problems. Absolute robustness has been thoroughly studied, whereas the others have been studied to less of a degree.     

Simulator for Aid of Trial-and-Error Design of Nonlinear Image Processing Filters

A simulator to aid in the design of nonlinear image processing filters is developed. This simulator assists the filter design by determining parameters manually by trial-and-error. The method is also useful for improving the results of the learning optimization methods. An example of the application of the technique to improve a resultant filter by a learning method of a mathematical morphological filter is shown.     

Efficient Algorithm for Learning Optimization Of Morphological Filters

An efficient algorithm based on the simulated annealing for the learning optimization of morphological filters is proposed. The learning stage is divided into two consecutive parts; the initial-learning stage finds and fixes the most important parts of the structuring elements, and the precise-learning stage determines details of the rest. This method significantly reduces the number of trials for the modification of structuring elements. The proposed algorithm is applied to the learning optimization of the bipolar morphological operation, whose optimization problem has not yet been investigated. It is shown experimentally that the algorithm optimizes the operator as efficiently as the conventional one and reduces the amount of calculation.     

Determination of ortho-phenylphenol residues in lemon rind by high-performance liquid chromatography with electrochemical detection using a microbore column.

A simple and highly sensitive method has been developed for determining ortho-phenylphenol (OPP) in lemon rind by high-performance liquid chromatography with electrochemical detection using a microbore column (microHPLC-ECD). Based on the voltammetric behavior of OPP, microHPLC-ECD was established using a CAPCELL PAK C-18 UG 120 microbore ODS column, 17 mM acetic acid-sodium acetate buffer (pH 4.0)/acetonitrile (60/40, v/v) as a mobile phase and an applied potential at +0.9 V vs. Ag/AgCl. The current peak height was found to be linearly related to the amount of OPP injected from 3.4 pg to 1.7 ng (r > 0.999). The detection limit (S/N = 3) was 3.4 pg (20 fmol), which was 100 times greater in terms of sensitivity when compared to conventional HPLC with UV detection. Standard OPP at 0.425 ng was detected with a relative standard deviation (RSD) of 1.9% (n = 10). The OPP contents in several lemon samples were determined by the present method. The recoveries of OPP from lemon rind exceeded 98% with an RSD (n = 5) of less than 3.01%.     

Diagnostic evaluation on cerebral hemisphere scintigraphy using 99mTc-MAA (author's transl)

Using 99mTc-labeled macroaggregated albumin (99mTc-MAA), we made an examination of the cerebral blood flow distribution with various kinds of cerebrovascular diseases in 151 cases. The particle size of MAA used in this study ranged from 10 to 100 micron. Scan was performed after injection of 3 mCi of 99mTc-MAA into common carotid artery. No side effects were observed except for one case with headache. Distribution of 99mTc-MAA was found to be homogeneous in normal cerebral hemisphere but not in the lesion. Most lesion was shown as nonradioactive area. Meningioma with hypervascularity was represented as hot area. By this method cerebral infarct could be easily represented not only in main artery but also in such a very small artery as hardly detected by CAG. This method is therefore useful for detecting cerebral infarct, sequela of cerebral apoplexy, head injury and others. The dose of 99mTc-MAA used in this method is much lower compared with those of common brain scan, its excretion is speedy, and therefore internal radiation exposure is diminished.     

Study of Probe-Surface Interaction in Shear-Force Microscopy: Effects of Humidity and Lateral Spring Constant

The shear force between a glass probe and a mica surface has been investigated as a function of the relative humidity, H, and the lateral spring constant of the probe, K. It was found that the interaction length D_o decreases with increasing H and exhibits a sharp drop around H=40%. With increase in K from 5 to 40 N/m, D_o gradually increases, although this feature was absent when a probe with a softer tip-end was used. The latter result indicates that the shear force in an atmospheric condition is not a remote force but results from some contact between the tip and the surface. Our results that D_o is independent of the oscillating amplitude and that the resonance curve of the probe is almost symmetric except in close vicinity to the surface are not in accord with the force model proposed recently, i.e., the knocking mechanism. It is proposed that the probe can vibrate even if the probe touches the surface, and that the resonance frequency increases steeply as the contact tightens. Theoretical estimation of the contribution of noncontact forces is also described.This paper was originally presented at the seventh Meeting on Near Field Optics, which was held on July 1, 1998 at Nagoya University, Nagoya, organized by Research Group on Near Field Optics, the Optical Society of Japan, an affiliate of the Japan Society of Applied Physics.     

Halogenation in achiral liquid crystals: terminal and linking substitutions

The effect on the physico-chemical properties of achiral liquid crystals of introducing halogen atoms into their terminal and linking groups is discussed and rationalized in terms of existing theories; a comparison is made with the corresponding hydrogenated and other well-known groups.     

The substituent effect on mesomorphic properties of 4-octyloxyphenyl 4-(4-R-3-nitrobenzoyloxy)benzoates and 4-(4-octyloxybenzoyloxy)phenyl 4-R-3-nitrobenzoates

The thermal properties of 4-octyloxyphenyl 4-(4-R-3-nitrobenzoyloxy) benzo-ates (1) and 4-(4-octyloxybenzoyloxy)phenyl 4-R-3-nitrobenzoates (2) have been examined, where R = hydrogen, halogens, alkyl and alkoxy groups. The derivatives of compound 1 incorporating hydrogen, halogens, methoxy and nitro groups show a smectic A phase having a bilayer arrangement, and the others with a long alkoxy group show the S_A phase with the monolayer arrangement. The derivatives of compound 2 incorporating halogens, and the nitro group show the S_A phase with the monolayer arrangement. The alkoxy derivatives show a smectic C phase as well as the nematic phase. The nitro group at the lateral position tends to increase the ratio of the S_A-N transition temperature to the N-I. The effect of the nitro group on the smectic properties has been discussed in terms of the structural and electrostatic nature of the nitro group.     

Determination of azide as the 3,5-dinitrobenzoyl derivative by capillary electrophoresis

A simple, rapid and reliable capillary electrophoresis method with a photodiode array detector was developed for determination of azide as the 3,5-dinitrobenzoyl derivative in drink samples fortified with sodium azide. Sample preparation was simple and rapid because no more than a simple dilution of samples is needed after quick derivatization. Separation was carried out using a buffer system comprising 25 mM phosphate buffer and 4 mM cetyltrimethylammonium hydroxide at pH 3.0. Methyl benzoate was selected as the internal standard (IS). This study investigated the influence of the concentration of phosphate buffer and electroosmotic flow (EOF) modifier, and the buffer pH on migration time and signal response. The optimized method made it possible to determine azide within 5 min. The limit of detection was determined to be 1.9 microg/ml with SIN > 3. The quantitation range was 6.5-323 microg/ml. By the method recoveries of azide in drink samples fortified with sodium azide were investigated. Mean recovery values ranged from 93.6 to 105.8% and results were satisfactory. In addition, no interference was observed in electropherograms of drink samples fortified with sodium azide. Thus, by this method, azide in drink samples can be determined rapidly with high recoveries and good selectivity despite extremely simple sample preparation.