• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.439-446
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• 2007

We carried out this experiment on the purpose to investigate the quality properties of aseptic-packaged cooked rice by cultivars in 2006. Brown rice was milled for white rice to 89.6% weight of it. Based on cluster analysis of acceptance of sensory evaluation, eleven rice cultivars of 29 cultivars had superior palatability. Whiteness(r=0.42, p<5%), lightness(r=0.39, p<5%), Toyo value(r=0.35, p<10%), and moisture content(r=0.33, p<10%) of milled rice were correlated positively with acceptability. Protein content(r=-0.40, p<5%), expansion rate(r=-0.68, p<1%) and water absorption rate(r=-0.42, p<5%) of milled rice, and yellowness(r=-0.45, p<5%) of aseptic-packaged cooked rice were negatively correlated. In sensory evaluation, correlation coefficients of taste and texture with acceptability were higher than those of appearance and flavor. During storage, hardness and cohesiveness of aseptic-packaged cooked rice before reheating were increased and decreased, but those after reheating had no difference based on storage period and cultivar. On the contrary, whiteness of reheated aseptic-packaged cooked rice with no distinct differences before reheating was decreased during storage. There were no significant differences of texture property, color characteristics and moisture contents by cultivar during storage.

• Journal of The Korean Association For Science Education
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• v.20 no.4
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• pp.527-541
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• 2000

The purpose of this study was to find out the characteristics of learning contents structure of K-12 science textbooks. The characteristics are related to 7 main concepts of matter properties; reaction rate, other reaction, density, solution, state change, absorption, and surface property. The contects are analyzed into 5 types of characteristics; type of concept extension, type of concept deepness, type of same level concept, type of confusion with other concepts, and type of concept interruption. First two types are positive content structures, but the others are negative structures. The findings are as follows. First, a lot of learning contents have the characteristic of 'type of same level concept'. There are few which have the characteristic of 'type of concept deepness'. Second, there are a lot of concepts related to 'properties of matter' which are not represented any more in middle and high school science textbooks. Those concepts are importantly taught in early childhood education and elementary school science. Most of the learning contents don't represent 'type of concept deepness'. Therefore the science textbooks needs to be restructuring.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.47-50
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• 2007

[ $ZnCr_2O_4$ ] shows geometrically frustrated magnet. Recently, $CoCr_2O_4$ has been investigated for multiferroic property and dielectric anomalies by spin-current model. Polycrystalline $CoCr_2O_4$ and $CoCrFeO_4$ compounds was prepared by wet-chemical process. Crystallographic and magnetic properties of $CoCr_2O_4$ and $CoCrFeO_4$ were investigate by using the x-ray diffractometer(XRD), vibrating sample magnetometer(VSM), superconducting quantum interference device magnetometer(SQUID), and $M\"{o}ssbauer$ spectroscopy. The crystal structure was found to be single-phase cubic spinel with space group of Fd3m. The lattice constants of $CoCr_2O_4$ and $CoCrFeO_4$ $a_0$ were determined to be 8.340 and 8.377 ${\AA}$, respectively. The ferrimagnetic transition temperature for the both samples were observed at 97 K and 320 K. The $M\"{o}ssbauer$ absorption spectra at 4.2 K show that the well developed two sextets are superposed with small difference of hyperfine field($H_{hf1}=507\;and\;H_{hf2}=492\;kOe$). Isomer shift values($\delta$) of the two sextets are found to be 0.33 and 0.34 mm/s relative to the Fe metal, respectively, which are consistent with the high spin $Fe^{3+}$ charge state.

• Korean Journal of Materials Research
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• v.18 no.6
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• pp.339-346
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• 2008

Single-crystal $ZnIn_2S_4$ layers were grown on a thoroughly etched semi-insulating GaAs (100) substrate at $450^{\circ}C$ with a hot wall epitaxy (HWE) system by evaporating a $ZnIn_2S_4$ source at $610^{\circ}C$. The crystalline structures of the single-crystal thin films were investigated via the photoluminescence (PL) and Double-crystal X-ray rocking curve (DCRC). The temperature dependence of the energy band gap of the $ZnIn_2S_4$ obtained from the absorption spectra was well described by Varshni's relationship, $E_g(T)=2.9514\;eV-(7.24{\times}10^{-4}\;eV/K)T2/(T＋489K)$. After the as-grown $ZnIn_2S_4$ single-crystal thin films was annealed in Zn-, S-, and In-atmospheres, the origin-of-point defects of the $ZnIn_2S_4$ single-crystal thin films were investigated via the photoluminescence (PL) at 10 K. The native defects of $V_{Zn}$, $V_S$, $Zn_{int}$, and $S_{int}$ obtained from the PL measurements were classified as donor or acceptor types. Additionally, it was concluded that a heat treatment in an S-atmosphere converted $ZnIn_2S_4$ single crystal thin films into optical p-type films. Moreover, it was confirmed that In in $ZnIn_2S_4$/GaAs did not form a native defects, as In in $ZnIn_2S_4$ single-crystal thin films existed in the form of stable bonds.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.35-40
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• 2013

In this study, the influence on the surface passivation properties of crystalline silicon according to silicon wafer thickness, and the correlation with a-Si:H/c-Si heterojunction solar cell performances were investigated. The wafers passivated by p(n)-doped a-Si:H layers show poor passivation properties because of the doping elements, such as boron(B) and phosphorous(P), which result in a low minority carrier lifetime (MCLT). A decrease in open circuit voltage ($V_{oc}$) was observed when the wafer thickness was thinned from $170{\mu}m$ to $50{\mu}m$. On the other hand, wafers incorporating intrinsic (i) a-Si:H as a passivation layer showed high quality passivation of a-Si:H/c-Si. The implied $V_{oc}$ of the ITO/p a-Si:H/i a-Si:H/n c-Si wafer/i a-Si:H/n a-Si:H/ITO stacked layers was 0.715 V for $50{\mu}m$ c-Si substrate, and 0.704 V for $170{\mu}m$ c-Si. The $V_{oc}$ in the heterojunction solar cells increased with decreases in the substrate thickness. The high quality passivation property on the c-Si led to an increasing of $V_{oc}$ in the thinner wafer. Short circuit current decreased as the substrate became thinner because of the low optical absorption for long wavelength light. In this paper, we show that high quality passivation of c-Si plays a role in heterojunction solar cells and is important in the development of thinner wafer technology.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.737-744
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• 1997

Four-dimensional response surface methodology was used for optimizing preparation conditions and monitoring sensory quality of instant rice gruel prepared using oyster mushroom and brown rice. Water absorption time of brown rice and glutinous rice to prepare instant rice gruel were 50 hr at $5^{\circ}C\;and\;1\;hr\;at\;20^{\circ}C$, respectively. The optimum conditions predicted for each corresponding sensory properties of instant rice gruel were 47.58% (rate of brown rice in water-absorbed brown and glutinous rice), 569.68 mL (content of solution) and 52.40 min (heating time at $120^{\circ}C$) in viscosity of instant rice gruel, 47.15%, 568.49 mL and 53.04 min in taste of instant rice gruel, 44.06%, 558.54 mL and 53.84 min in mouth-feel of instant rice gruel, and 46.20%, 561.64 mL and 51.60 min in overall acceptance of instant rice gruel, respectively. The optimum conditions, which satisfy all sensory properties of rice gruel, were 44%, 620 mL and 56 min in rate of brown rice in water-absorbed brown and glutinous rice, content of solution and heating time, respectively. Sensory scores predicted at the optimum conditions were in good agreement with experimental sensory scores.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.573-579
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• 1996

Crosslinked potato starches (XP), from 2,400 to 1,900 anhydroglucose units per crosslinked (AGU/CL), were prepared by reacting with epichlorohydrin. Some of the physicochemical properties of the XPs were then compared with those of native potato and cowpea starches. Crosslinking decreased moisture, protein and ash contents but had no effect on phosphorus content. Water binding capacities of the XPs increased as the degree of crosslinking increased, and that of the XP with 2,100 AGU/CL approached the value of cowpea starch. The absorption maxima of the starch-iodine complex shifted from 594 to 580 nm. Granule size increased slightly and surface appearance of the granule became rough when crosslinked. Both native and crosslinked potato starches showed B type X-ray diffraction pattern, and the relative crystallinity was not affected by crosslinking. Gelatinization temperature and the heat of gelatinization, measured by differential scanning calorimeter (DSC), did not change within the range of crosslinking tested. From X-ray and DSC data, it was concluded that the crosslinking ocurred in the amorphous region of the starch granule.

• Membrane Journal
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• v.26 no.2
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• pp.126-134
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• 2016

To produce renewable biomethane from biogas, the properties of physical absorbents such as water, methanol, 1-methyl-2-pyrrolidone (NMP), poly(ethylene glycol) dimethylether (PEGDME), and propylene carbonate (PC) were studied, and PC was applied to membrane contactor systems. Among physical absorbents, PC exhibited a high contact angle of $58.3^{\circ}$ on polypropylene surface, and a PC/water mixture (5 wt%) increased the contact angle to $90^{\circ}$. Furthermore, the PC/water mixture presented higher $CO_2$ absorption capacities (0.148-0.157 mmol/g) than that of water (0.121 mmol/g), demonstrating a good property as an absorbent for membrane contactors. Actual operations in membrane contactors using the PC/water mixture resulted in $CO_2$ removal of 98.0-97.8% with biomethane purities of 98.5-98.3%, presenting a strong potential for biogas treatment. However, the PC/water mixture yielded moderate improved in $CO_2$ removal and methane recovery, as compared with water in the membrane contactor operation. This is originated from insufficient desorption processes to reuse absorbent and low $CO_2$ flux of the PC/water absorbent. Thus, it is requiring optimizations of membrane contactor technology including development of absorbent and improvement of operation process.

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.757-762
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• 2005

Characteristics of cereals prepared by extrusion-cooking and freeze-drying were compared. Parameters used were water solubility index (WSI), water absorption index (WAI), paste viscosity, and sterilization. Variables for extrusion process were barrel temperature at die section (70, 90, and $110^{\circ}C$) and moisture content (25 and 30%). WAI and WSI of extruded cereals were higher, whereas trough, breakdown, and final viscosity were lower than those of raw and freeze-dried cereals. Plate counting revealed no microbes in extruded cereals, whereas microbe colony was observed in freeze-dried cereals. Extrusion-cooking at low temperature resulted in better sterilization of microbes than freeze-drying for preparation of instant cereal drinks.

• Journal of Gastric Cancer
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• v.3 no.2
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• pp.93-96
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• 2003

Purpose: Synthetic absorbable monofilaments offer excellent glide characteristics and cause minimal tissue trauma as a result of their smooth monofilament structure and gradual absorption within the healing tissues. For these reasons, these suture materials are commonly used in various surgical fields such as gastroenterology, urology, gynecology, and plastic surgery. The aim of this study was to evaluate the safety and usefulness of a new synthetic absorbable monofilament, Glycoside-..-caprolactone-trimethylene carbonate interpolymer (GCT), in gastrointestinal anastomosis and closure. Materials and Methods: We evaluated 55 gastrointestinal anastomoses and closures using GCT $MONOSYN^{R}$, B. Braun, Germany) in 47 patients who underwent gastric surgery between December 2001 and May 2002 at Seoul National University Hospital. Patient's characteristics, operative procedure, surgeon's opinion of handling properties of GCT, and suture-related complications were analyzed. Results: There were 34 males and 13 females (M:F= 2.6:1) with an average age of 54.2 years old. Forty-five cases of gastrointestinal anastomosis (20 gastrojejunostomies and 25 jejunojejunostomies) and 10 cases of intestinal closure (7 gastrostomy closures and 3 duodenal stump closures) were performed in 41 cases of stomach cancer, three of peptic ulcer disease, two of GIST, and one MALToma. The handling properties of GCT according to the criteria of knot breaking load, knot security, and placing property were always scored with 7 to 9 points (10=excellent, 1=very poor). Two cases of postoperative complications ($3.6\%$) were noted. One was a leak of the gastrojejunostomy site which was successfully managed conservatively, and the other was a stricture of the gastrojejunostomy site which was managed by reoperation (side-to-side jejunojejunostomy). Conclusion: GCT seems to be an applicable suture material for various gastrointestinal anastomoses and closures.