Despite numerous advances in the preparation and use of GaN, and many leading-edge applications in lighting technologies, the preparation of high-quality GaN powder remains a challenge. Ammonolytic preparations of polycrystalline GaN have been studied using various precursors, but all were time-consuming and required high temperatures. In this study, an efficient and low-temperature method to synthesize high-purity hexagonal GaN powder is developed using sub-micron Ga2O3 powder as a starting material. The sub-micron Ga2O3 powder was prepared by an ultrasonic spray pyrolysis process. The GaN powder is synthesized from the sub-micron Ga2O3 powder through a nitridation treatment in an NH3 flow at 800℃. The characteristics of the synthesized powder are systematically examined by X-ray diffraction, scanning and transmission electron microscopy, and UV-vis spectrophotometer.

최근 합성첨가물에 대한 소비자들의 거부감이 증가하면서 천연물 유래하는 항산화제, 항균제 등의 개발에 대한 연구가 증가하고 있다. 어성초(Hottuynia cordata)는 흔히 약모밀로 불리는 다년생 초본의 야생약초로서, 항균, 항암, 항바이러스 등의 다양한 생리활성 기능이 있다고 알려져 있으며, 이러한 다양한 효능은 어성초 부위와 추출 방법에 따라 다양한 생리활성물질 때문으로 알려져 왔다. 본 연구에서는 어성초의 잎과 뿌리를 이용하여 열수 추출과 70% 에탄올 추출을 하면서 초음파(ultrasonication) 처리 유무에 따른 추출물의 항산화 및 항균 효과를 비교하였다. 열수 추출에서는 건조된 잎줄기와 뿌리 분말 30 g을 300 mL의 증류수에 넣고, 80℃에서 24시간 추출하여 상등액을 취하고, 다시 같은 양의 증류수로 3회 반복하여 추출하였다. 용매 추출은 각 분말 30 g을 300 mL의 70% 에탄올에 넣고 밀폐시킨 후 40℃ 오븐에서 24시간 추출한 후 상등액을 취하고, 같은 방법으로 3회 반복하여 추출하였다. 열수 추출과 용매 추출 방법에서 초음파 처리에 의한 효과를 비교하기 위해 분말을 증류수 또는 에탄올에 침지 시킨 후 probe type의 초음파기로 20분 동안 처리 한 후 24시간 동안 추출하였다. 추출물은 감압 농축 후 동결건조하여 항산화 및 항균 효과를 평가하였다. ABTS 라디칼 소거활성 결과 잎줄기 추출물이 뿌리 추출물에 비해 항산화 효과가 우수하였고, 열수 추출보다는 에탄올 추출이 효과가 높았으며, 초음파 처리를 병행한 경우 유의적인 증가를 보였다. 잎줄기를 초음파를 병행한 에탄올 추출조건에서 RC50값이 1.09 mg/mL로 가장 낮은 값을 나타내었다.

본 연구는 강산성차아염소산수(SAHW)와 초음파(UW)를 병용한 조미오징어 반가공품의 미생물 오염도 저감 기술을 개발하고자 수행되었다. SAHW의 유효염소농도는 69.67 ± 0.58 ppm, ORP는 1071.33 ± 4.16 mV, pH는 2.79 ± 0.05이었다. 오징어 반가공품을 중량대비 20배의 SHS에 120분간 침지하였을 때 일반세균은 1.49 log CFU/g, 황색포도상구균은 1.32 log CFU/g 감소하였으며, 대장균은 검출한계 이하로 감소하였다. 오징어 반가공품 중량대비 10배의 SAHW에 120분간 침지한 경우, 일반세균은 2.69 log CFU/g, 황색포도상구균은 1.74 log CFU/g 감소하였으며, 20배의 SAHW에 120분간 침지한 경우, 일반세균은 3.62 log lCFU/g, 황색포도상구균은 3.22 log CFU/g 감소하였으며, 대장균은 검출되지 않아 SAHW가 같은 유효염소농도의 SHS보다 살균력이 높은 것을 알 수 있었다. SAHW 단독 처리만으로는 만족할 만한 미생물 저감효과를 얻을 수 없었기에 조미오징어 반가공품을 SAEW에 1차 침지 처리한 후, SAHW에 2차 침지 처리한 결과, 오징어 반가공품 중량 대비 20배의 SAEW로 60분 처리한 후, SAHW로 처리하였을 때는 중량대비 10배, 120분 처리, 중량대비 20배, 90분 처리로 일반세균수는 약 4.0 log CFU/g, 황색포도상구균은 규제치(log 2.0 CFU/g 이하) 이하로 감소하였으며 대장균은 검출되지 않았다. 초음파 세정기에 오징어 반가공품과 중량대비 20배의 TW, SHS, SAHW를 각각 넣어 UW 처리한 후 미생물 오염도를 조사한 결과, SAHW로 60분간 처리하였을 때 일반세균은 검출한계(< 1.00 log CFU/g) 이하로 감소하였으며 황색포도상구균은 규제치 이하로 감소하여 가장 좋은 저감효과를 나타내었다. 대장균의 경우, SAHW 10분간 처리로도 검출한계 이하로 감소하여 SAHW와 UW의 병용이 조미오징어 반가공품 미생물 저감화에 가장 효과가 좋은 것을 알 수 있었다.

The effects of ultrasound and enzyme treatments on reducing sugar production from Korean 6-row barley Dahyang during the mashing process of brewing were studied. The concentration of reducing sugar produced by the traditional method was 41.5 mg/mL. The treatment of both the ultrasound at 400 W and amyloglucosidase (0.1 U/mL) increased the reducing sugar concentration produced in the mashing process by 15% compared to the traditional method. In addition, both treatments reduced the total mashing time from 115 min to 70 min. The combination of ultrasound and amyloglucosidase treatment increased the reducing sugar production yield by 17% during mashing, in comparison with the traditional method.

This study was performed to compared the effectiveness of individual treatments (electrolyzed water: EW, organic acid, and ultrasound) and their combination on reducing foodborne pathogens from perilla leaves. Perilla leaves were innoculated with a cocktail of Salmonella Typhimurium, Staphylococcus aureus, Bacillus cereus. Inoculated perilla leaves were treated with EW combined with different concentration of acetic acid (0.5%, 1.0%, 1.5%, 2.0%) for 1 min at room temperature. Treatment of 3 pathogens on perilla leaves with electrolyzed water combined with ultrasound (25 kHz) and 0.5% acetic acid was also performed for 1 min. While the numbers of S. Typhimurium and B. cereus showed reduced with increasing acetic acid concentration, there is no difference in the number of S. aureus treated with EW containing 0.5% to 1.5% acetic acid. Discoloration was observed the perilla leaves treated with EW combined with more than 1.0% acetic acid. For all three pathogens, the combined treatment of EW and ultrasound resulted in additional 0.42 to 0.72 log10 CFU/g. The maxium reductions of S. Typhimurium and B. cereus were 0.95, 1.23 log10 CFU/g after treatment with EW combined with 0.5% acetic acid and ultrasound simultaneously. The results suggest that the treatment of EW combined with 0.5% acetic acid and ultrasound increased pathogens reduction compared to individual treatment.

일부 고주파 음파 처리가 파밤나방(Spodoptera exigua)의 생리변화를 유발시킨다. 이 연구는 초음파( 20 kHz) 처리가 파밤나방 유충 섭식, 용 발육 및 성충 교미행동에 미치는 영향을 분석하였다. 초음파 처리는 5령충의 섭식 활동을 억제시켰다. 특별히 30 kHz 또는 45 kHz 초음파 처리를 받은 유충은 50% 이상의 섭식활동이 감소하였다. 이러한 초음파 처리를 받은 유충은 혈장의 주요 영양물질 함량이 변동되었다. 혈장 단백질은 처리 초음파의 주파수 증가에 따라 감소하였다. 그러나 혈당은 처리 초음파의 주파수 증가에 따라 증가하였다. 지질 함량은 30 kHz 처리까지는 증가하다가 이후 감소하였다. 파밤나방 5령의 혈구, 지방체 및 표피세포의 세 조직은 스트레스 관련 유전자들인 세 종류의 열충격단백질과 apolipophorin III를 발현시켰다. 그러나 초음파를 처리할 경우 일부 스트레스 관련 유전자들의 발현을 크게 억제시켰다. 초음파 처리는 또한 용발육을 억제시켜, 용기간을 연장시키고 성충으로 우화를 현격하게 낮추었다. 끝으로 초음파 처리는 성충의 교미행동을 억제시켜 암컷의 산란력을 뚜렷하게 낮추었다. 이러한 결과는 초음파가 파밤나방의 생리적 스트레스로 작용하고 있다는 것을 제시하고 있다.

본 연구에서는 추출보조공정으로서 초음파 처리에 따른 녹차의 성분특성 변화를 분석하기 위하여, 60℃에서 1, 5, 30, 60분간 열수추출하고, 동일온도에서 초음파 추출하여 각각 가용성 고형분, vitamin C, 총 페놀성 화합물, flavonols, catechins, caffeine, free amino acids 함량을 분석하였다. 가용성 고형분 함량은 초음파 처리에 의해 약 4~5%의 추출수율이 증가하였다. Viamin C 함량은 1, 5, 30분에서는 각각 약 0.21, 0.16, 0.31 mg/g 증가하였지만, 60분 처리구에서는 대조구와 비교해 2.47 mg/g에서 2.22 mg/g으로 감소하였고, 총 페놀성 화합물 함량이 약 10~13 mg/g 증가하였다. Flavonols는 myricetin이 4.77 mg/100g에서 9.94 mg/100g, quercetin은 10.97 mg/100g에서 20.84 mg/100g, kaempferol은 7.95 mg/100g에서 17.33 mg/100g으로 초음파 처리에 의해 약 2배 이상 증가함을 알 수 있었다. 초음파 처리에 의해 녹차 침출액의 EGCG, EGC, ECG, EC, (+)-C 함량이 증가하는 경향을 보였다. 이러한 경향과는 달리, 유리아미노산의 경우는 초음파 처리에 따른 영향이 거의 없었고, 추출시간이 길어짐에 따라 증가하는 경향을 보였다. 결론적으로 초음파 처리에 의해 녹차의 vitamin C, 총 페놀 화합물, flavonol류, catechins의 추출이 증가함을 알 수 있었고, 따라서 녹차 가공에 있어 초음파 처리가 매우 효율적인 추출보조공정으로 사용될 수 있으리라 사료된다.

ZnO nanorod gas sensors were prepared by an ultrasound radiation method and their gas sensing properties were investigated for NO gas. For this procedure, 0.01, 0.005 and 0.001M of zinc nitrate hydrate [Zn(NO3)2 · 6H2O] and hexamethyleneteramine [C6H12N4] aqueous solutions were prepared and then the solution was irradiated with high intensity ultrasound for 1 h. The lengths of ZnO nanorods ranged from 200 nm to 500 nm with diameters ranging from 40 nm to 80 nm. The size of the ZnO nanorods could be controlled by the concentration of solution. The sensing characteristics of these nanostructures were investigated for three kinds of sensor. The properties of the sensors were influenced by the morphology of the nanorods.

All crude oil carries a little of water, sand, and mineral sediment molecules tightly bounded with hydrocarbons. The result is the gradual precipitation of these heavier elements into thick, granular petroleum by products known as crude oil sludge. The oily sludges in ship tanks and in storage facilities have to be treated efficiently in order to keep the security and the capacity of storage facilities, to protect a serious environmental pollution, and to retrieve lost resource. The oily sludge treatment system should be designed to satisfy requirements mentioned in safe work condition. As a basic study, in this paper, an oily sludge treatment system by ultrasonic waves was proposed. Then, the features of ultrasonic energy and recovery of sludge with ultrasonic waves are investigated by experiments. As results, we found that ultrasonic waves are a new energy to flow oil sludge environment-friendly in safe work condition. In addition, it was shown that ultrasonic energy is more efficient than thermal energy in treating oil sludge, and that the volume of wastes for disposal is reduced remarkably.

The present study was carried out to evaluate the effect of superovulation treatments on ovarian responses, oocyte recovery rates and grades of collected oocytes using an ultrasound-guided transvaginal approach in Korean native cows. Superovulation in cows was induced with two different regimenes: 1) FSH-decreasing dose(n=8): the cows were received twice per day for three days of the total dose of 400 mg of FSH-p, 2) FSH-single dose(n=9): the cows were administrated a single dose of 400 mg of FSH-p in 25% PVP. The Observation of visible follicles and collection of oocytes were performed 12 hours following the last FSH in FSH-decreasing dose group and 48 hours after the FSH-single dose injection. All visible follicles larger than 6 mm were punctured and aspirated with a 6.5 MHz convex-array ultrasound transducer designed for intravaginal use. The mean number of visible follicles(> 6 mm) was significantly(P<0.05) higher in the FSH-decreasing dose treatment (22.811.9) and FSH-single dose treatment (20.612.0) groups than the non-treatment group(7.08). The mean recovery rate of oocytes was not significantly(P<0.05) different between the treatment and control groups, but the mean number of collected oocytes was significantly(P<0.05) higher in the FSH-decreasing dose treatment( 12.611.5) and FSH-single dose treatment (11.813.6) groups than the non-treatment group(3.70.5). In conclusion, the FSH-single dose treatment at superovulation in cows for ultrasound-guided aspiration might increase the number of aspiratable follicles and the recovery rate of follicular oocytes as the FSH-decreasing dose treatment.

The aim of this study was to evaluate the effect of recombinant bovine somatotropin (bST; Boostin-S, LG Chem) treatment with FSH (Super OV) or PMSG on superovulatory response for transvaginal ultrasound-guided oocyte retrieval (TVR) in calves. Eight Korean Native Cattle(KNC) heifer calves; 150 to 240 days old; were randomly assigned to four treatment groups: 1) FSH(75 mg); 2) FSH (75 mg) + bST(500mg) 3) PMSG(1;000 IU); 4) PMSG(1, 000 IU) + bST(500 mg). Experimental calves in group 1 (n=2) and 2(n=2) were weekly superovulated for 4 consecutive weeks with daily injection of FSH for 3days and the next day subjected to TVR session. Animals in group 3 (n=2) and 4(n=2) were weekly stimulated for 4 consecutive weeks with a single dose of 1, 000 IU PMSG. TVR was performed on 72 hours after PMSG injection. Calves in group 2 and 4 was received injection of 500 mg of bST every 10 days. At each TVR session, follicle number and size were recorded; the oocytes collected and graded according to cumulus and cytoplasm investment. Collected oocyte were determined viable oocyte according to morphological quality with granulation of oocyte and number and status of cumlulus cells. IVM and IVF were performed and assessed cleavage rate on day 3 after fertilization. A Sonovet 600(Medison, Co., Ltd) realtime ultrasound scanner with a 6.5 MHz convex transducer, fixed at the tip of 500 mm estended handle equipped with a needle guide was used in collecting oocyte. Differences between groups were analysed by chi-square test. The population of large follicle (5 nun) and aspiration rate were not significant different among the 4 groups. But, the number of small follicles (<5 mm) and aspirated oocyte in the KNC calves treated with bST were 1.3~1.6 times higher than in KNC calves treat with FSH or PMSG alone. In conclusion, the administration of bST with FSH or PMSG at superovulation for TVR in calves was increase the nurnber of small follicle which was influenced the number of aspiratable follicle.