• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.855-858
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• 2003

Carbon nanotubes (CNTs) were grown on Ni-coated TiN/Si substrate by microwave plasma chemical vapor deposition using mixture gas of $H_2/CH_4$ at low temperature of 500 $^{\circ}C$. Average diameter of CNTs could be easily controlled by $H_2$ plasma pretreatment time before CNTs growth. The turn-on voltages of CNT emitters were varied from 3.5 $V/{\mu}m$ to 9 $V/{\mu}m$ according to the hydrogen pretreatment conditions. The close relationship between electron emission characteristics and pretreatment time indicates that pretreatment condition can be a key process parameter in CNTs growth for field emission displays..

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.650-654
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• 2007

In our previous work, a method of pretreating lipase was developed to prevent loss of its activity during covalent immobilization. In this study, Rhizopus oryzae lipase was pretreated before immobilization and then immobilized on a silica gel surface. The effects of the various materials and conditions used in the pretreatment stage on the activity of immobilized lipase were investigated. Immobilized lipase pretreated with 0.1% of soybean oil had better activity than those pretreated with other materials. The optimal temperature, agitation speed, and pretreating time for lipase pretreatment were determined to be $40^{\circ}C$, 200rpm, and 45min, respectively. The activity of immobilized soybean oil pretreated lipase was 630U/g matrix, which is 20 times higher than that of immobilized non-pretreated lipase. In addition, immobilized lipase activity was maintained at levels exceeding 90% of its original activity after 10 reuses.

• KSBB Journal
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• v.28 no.5
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• pp.315-318
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• 2013

Ethanol fermentations were performed using separate hydrolysis and fermentation (SHF) processes with monosaccharides from pretreated seaweed, Eucheuma spinosum as the biomass. The pretreatment was carried out with 11% (w/v) seaweed slurry and 150 mM $H_2SO_4$ at $121^{\circ}C$ for 40 min. Enzyme hydrolysis after $H_2SO_4$ pretreatment was performed with Celluclast 1.5 L at $45^{\circ}C$ for 24 h. Five % active charcoal were added to hydrolysate to removed 5-hydroxy methylfurfural. Ethanol fermentation with 11% (w/v) seaweed hydrolysate was performed for 72~96 h using Kluyvermyces marxianus, Pichia stipits, Saccharomyces cervisiae and Candida tropicalis. Ethanol concentration was reached to 18 g/L by K. marxianus, 16 g/L by P. stipitis, 15 g/L by S. cerevisiae and 10 g/L by C. tropicalis, respectively. The ethanol yield from total monosugar was obtained 0.50 and ethanol productivity was obtained 0.38 g/L/h by K. marxianus.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.526-532
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• 2008

The proposed $CO_2$ storage technology in the present study is a one-step sequestration process that stabilizes $CO_2$ in a reactor with Serpentine. The advantage of this technology is associated with its high stability of final product so that the entire system is recognized as permanent environment-friendly $CO_2$ removal method. Since the sequestration reaction mechanisms are generally understood that carbonation reaction proceeds with very slow rate, so that pretreatment method to increases reaction rate of $CO_2$ carbonation reaction should be developed. To increase the reactivity of Serpentine with $CO_2$, two different methods of pretreatment are carried out in the present investigation. One is heat-treatment, the other is chemical pretreatment. In this study, only chemical pretreatment is considered leaching method of magnesium from Serpentine using sulfuric acid at the various reaction temperatures, times, and acid concentrations. Experimental results illustrated that pretreatment by sulfuric acid increases surface area of serpentine from $11.1209m^2/g$ to $98.7903m^2/g$ and extracts magnesium compounds. Single variable experiment demonstrated the enhancements of magnesium extraction with increased reaction temperature and time. Amount of magnesium extraction is obtained by using the data of ICP-AES as maximum extraction condition of magnesium is 2 M acid solution, $75^{\circ}C$ and 1hr. After performing chemical pretreatment, carbonation yield increased from 23.24% to 46.30% of weight.

• KSBB Journal
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• v.28 no.6
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• pp.366-371
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• 2013

Ethanol productions were performed by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes using seaweed, Enteromorpha intestinalis (sea lettuce). Pretreatment conditions were optimized by the performing thermal acid hydrolysis and enzymatic hydrolysis for the increase of ethanol yield. The pretreatment by thermal acid hydrolysis was carried out with different sulfuric acid concentrations in the range of 25 mM to 75 mM $H_2SO_4$, pretreatment time from 30 to 90 minutes and solid contents of seaweed powder in the range of 10~16% (w/v). Optimal pretreatment conditions were determined as 75 mM $H_2SO_4$ and 13% (w/v) slurry at $121^{\circ}C$ for 60 min. For the further saccharification, enzymatic hydrolysis was performed by the addition of commercial enzymes, Celluclast 1.5 L and Viscozyme L, after the neutralization. A maximum reducing sugar concentration of 40.4 g/L was obtained with 73% of theoretical yield from total carbohydrate. The ethanol concentration of 8.6 g/L of SHF process and 7.6 g/L of SSF process were obtained by the yeast, Saccharomyces cerevisiae KCTC 1126, with the inoculation cell density of 0.2 g dcw/L.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.734-737
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• 2006

This study was carried out to establish the manufacturing process of barley leaf powder tea. The optimal manufacturing process among many trials was determined with sensory evaluation. Finally established process and operation conditions were as follows: pretreatment (cutting and washing), steaming ($100^{\circ}C$, 30 sec), primary drying and roasting ($130^{\circ}C$, 40 min), rolling (RT, 25 min), middle drying and roasting ($60^{\circ}C$, 30 min), final drying and roasting ($55^{\circ}C$, 25 min), drying ($60^{\circ}C$, 20 min), roasting ($85^{\circ}C$, 20 min), and powdering (120 mesh). The barley leaf powder tea produced by this process mainly consisted of dietary fiber (33.8%), amino acids (12.9%), minerals (4.7%) and ${\beta}-carotene$ (6.9 mg%).

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.255-264
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• 2009

To evaluate the effects of chemical pretreatments of lignocellulosic biomass on enzymatic hydrolysis process, Populus euramericana was pretreated for 1 hr with 1% sulfuric acid ($H_2SO_4$) at $150^{\circ}C$ and 1% sodium hydroxide (NaOH) at $160^{\circ}C$, respectively. Before the enzymatic hydrolysis, each pretreated sample was subjected to drying process and thus finally divided into four subgroups; dried or non-dried acid pretreated samples and dried or non-dried alkali pretreated samples and chemical and physical properties of them were analyzed. Biomass degradation by acid pretreatment was determined to 6% higher compared to alkali pretreatment. By the action of acid ca. 24.5% of biomass was dissolved into solution, while alkali degraded ca. 18.6% of biomass. However, reverse results were observed in delignification rates, in which alkali pretreatment released 2% more lignin fragment from biomass to the solution than acid pretreatment. Unexpectedly, samples after both pretreatments were determined to somewhat higher crystallinity than untreated samples. This result may be explained by selective disrupture of amorphous region in cellulose during pretreatments, thus the cellulose crystallinity seems to be accumulated in the pretreated samples. SEM images revealed that pretreated samples showed relative rough and partly cracked surfaces due to the decomposition of components, but the image of acid pretreated samples which were dried was similar to that of the control. In pore size distribution, dried acid pretreated samples were similar to the control, while that in alkali pretreated samples was gradually increased as pore diameter increased. The pore volume which increased by acid pretreatment rapidly decreased by drying process. Alkali pretreatment was much more effective on enzymatic digestibility than acid pretreatment. The sample after alkali pretreatment was enzymatically hydrolyzed up to 45.8%, while only 26.9% of acid pretreated sample was digested at the same condition. The high digestibility of the sample was also influenced to the yields of monomeric sugars during enzymatic hydrolysis. In addition, drying process of pretreated samples affected detrimentally not only to digestibility but also to the yields of monomeric sugars.

• Analytical Science and Technology
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• v.13 no.6
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• pp.731-735
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• 2000

The acid digestion bomb pretreatment method for the determination of antimony in a commercial fire retardant material sample (DBDPE-$Sb_2O_3$) was studied. DBDPE-$Sb_2O_3$ sample was digested with $H_2SO_4:HCl$(1:2) mixture in digestion bomb at $220^{\circ}C$ for 2 hrs. and antimony was determined by atomic absorption spectrophotometry. Recovery of 99.6-99.8% and C.V. of 0.94-1.07% for Sb was obtained for spiked real samples. In the present method, the analytical results obtained for antimony were 40.3 and 36.3% (w/w), respectively.

• KSBB Journal
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• v.28 no.5
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• pp.282-286
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• 2013

The seaweed, Gelidium amansii, was fermented to produce bioethanol. Optimal pretreatment condition was determined as 94 mM $H_2SO_4$ and 8% (w/v) seaweed slurry at $121^{\circ}C$ for 60 min. The mono sugars of 40.4 g/L with 67% of conversion from total carbohydrate of 60.6 g/L with 80 g dw/L G. amansii slurry were obtained by thermal acid hydrolysis pretreatment and enzymatic saccharification. G. amansii hydrolysate was used as the substrate for ethanol production by Kluyveromyces marxianus KCTC 7150 and Candida tropicalis KCTC 7212 using 5L fermentor. The ethanol productions by K. marxianus KCTC 7150 and C. tropicalis KCTC 7212 were 17.8 g/L with $Y_{EtOH}$ of 0.48 at 120 h and 19.3 g/L with $Y_{EtOH}$ of 0.50 at 120 h, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.253-253
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• 2010

Rice straw was pretreated with aqueous ammonia in order to enhance enzyme digestibility. Soaking in ammonia aqueous (SAA) was conducted with 15% ammonia, at $60^{\circ}C$. for 24 h. Optimization of both saccharification conditions and enzyme loading of SAA rice straw was carried out. Especially enzyme loading test was performed using statistical method. Moreover proton beam irradiation (PBI) was also performed to overcome the problem which inhibit the enzyme digestibility at 1-25 kGy doses with 45 MeV of beam energy. Optimal condition for enzymatic saccharification was follows; pH 4.8, $50^{\circ}C$, 60 FPU of enzyme activity, 1:4 ratio of celluase and ${\beta}$-glucosidase. Also, optimal doses of PBI on rice straw and SAA-treated rice straw for efficient sugar recovery were found to be 3 kGy, respectively. When saccharification was performed with optimal condition, glucose conversion yield was 89% of theocratical maximum in 48 h, and 3 kGy of PBI was applied to SAA-treated rice straw, approximately 90% of the theoretical glucose yield was obtained in 12 h. The results of X-ray diffractometry (XRD) support the effect of both SAA and PBI on sugar recovery, and scanning electron microscopy (SEM) images unveiled the physical change of the rice straw surface since rugged rice straw surface was observed.