• 펄프종이기술
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• 제47권4호
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• pp.81-87
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• 2015

Soda-AQ pulp made from sugarcane bagasse (SCB) were bleached in element chlorine free (ECF) sequence. To reduce chlorine dioxide use, final peroxide bleaching was introduced. Prior to peroxide bleaching, different chelating chemicals were applied for comparative analysis in ISO brightness and viscosity. When using equal total chlorine dioxide usage (4.5%), bleached SCB pulp using chelate and hydrogen peroxide (DEDQP) was reached 86.8% (DTPA), 86.4% (EDTA) ISO brightness, whereas bleached pulp using only hydrogen peroxide (DEDP) reached at 81.2% ISO brightness. Viscosity of DEDQP bleached pulp was 25.6 cPs (DTPA), 25.2 cPs (EDTA), And DEDP bleached pulp was shown 18.0 cPs viscosity. Decreasing of transition metal by chelate process led to improvements in final brightness along with higher viscosity. Due to EDTA is 5-7 times cheaper than DTPA, EDTA is recommended as chelating chemical prior to peroxide bleaching.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 춘계학술대회 논문집
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• pp.237-238
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• 2003

과산화수소와 organic peroxide는 대류권내 광화학반응에서 생성되는 중요 부산물이다. 이들은 대류권내의 OH와 HO$_2$ 라디칼의 농도를 지시하여 대기의 산화도를 나타내는 지시자가 된다. 이 라디칼들은 $O_3$를 생성하는데 필수적인 성분이므로, 대류권내 광화학 반응을 이해하기 위해서는 과산화수소의 농도와 분포를 이해하는 것이 필수적이다. 대기중의 hydroperoxide는 유리코일 내에서 포집 용액에 의해 포집된 후 HPLC 시스템의 postcolumn reactor에서 효소와 반응하여 형광을 띠게 되고, 형광검출기에서 검출된다. 이 모든 과정은 자동화되어 과산화수소의 실시간 관측 및 연속관측이 가능하게 되었다. (중략)

• Bulletin of the Korean Chemical Society
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• 제27권10호
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• pp.1674-1676
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• 2006

• 대한화학회지
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• 제59권6호
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• pp.554-559
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• 2015

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.629-630
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• 2014

• 대한화학회지
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• 제48권6호
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• pp.654-658
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• 2004

• 한국보건교육건강증진학회:학술대회논문집
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• 한국보건교육건강증진학회 2007년도 춘계학술대회 자료집
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• pp.151-153
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• 2007

• 펄프종이기술
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• 제48권1호
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• pp.100-110
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• 2016

Alkaline Peroxide Mechanical Pulping (APMP) of Pinus densiflora harvested from domestic mountains was explored. APMP contributes to various advantages including pulp quality, elimination of the need for a bleaching process, and energy savings. Sequential treatment of impregnation of bleaching chemicals and refining not only overcome the concern of alkaline darkening of wood chips during chemical impregnation, but it also brightens the chips to the desired brightness levels suitable for writing and printing papers. APMP pulping from Pinus densiflora was greatly influenced by the dosage levels of hydrogen peroxide and sodium hydroxide. Alkaline peroxide treatment was carried out by applying one of three levels of hydrogen peroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips) and one of three levels of sodium hydroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips). Other chemicals including a peroxide stabilizers and metal chelation were constantly added for all treatments. Chemical treatment with a liquor-to-wood ration of 9:1 was carried out in a laboratory digestor. Compared to BTMP, APMP pulping displayed outstanding characteristics including the less requirement of refining energy, the better improvement of tensile strength, the more reduction of shives, and the greater increase of pulp brightness. In particular, when 4.5% of hydrogen peroxide with impregnation during 90 minutes was used, the brightness of APMP reached 64.9% ISO. Even though bulk of APMP was decreased with the increase of sodium hydroxide, a better and improved balance could be achieved between optical and strength properties. The spent liquor obtained from the discharge of the impregnation process at the dosage level of 4.5% hydrogen peroxide exhibited an equal level of residual peroxide with BTMP. In conclusion, APMP pulping showed successful results with Pinus densiflora due to its better response to the development of optical and physical properties compared to TMP pulping.

• The Journal of Advanced Prosthodontics
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• 제8권2호
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• pp.94-100
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• 2016

PURPOSE. To evaluate the effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement. MATERIALS AND METHODS. The specimens were prepared to evaluate the bond strength of epoxy resin-based fiber posts (D.T. Light-Post) to dual-curing resin cement (RelyX U200). The specimens were divided into four groups (n=18) according to different surface treatments: group 1, no treatment; group 2, silanization; group 3, silanization after hydrogen peroxide etching; group 4, silanization with warm drying at $80^{\circ}C$ after hydrogen peroxide etching. After storage of the specimens in distilled water at $37^{\circ}C$ for 24 hours, the shear bond strength (in MPa) between the fiber post and resin cement was measured using a universal testing machine. The fractured surface of the fiber post was examined using scanning electron microscopy. Data were analyzed using one-way ANOVA and post-hoc analysis with Tukey's HSD test (${\alpha}=0.05$). RESULTS. Silanization of the fiber post (Group 2) significantly increased the bond strength in comparison with the non treated control (Group 1) (P<.05). Heat drying after silanization also significantly increased the bond strength (Group 3 and 4) (P<.05). However, no effect was determined for hydrogen peroxide etching before applying silane agent (Group 2 and 3) (P>.05). CONCLUSION. Fiber post silanization and subsequent heat treatment ($80^{\circ}C$) with warm air blower can be beneficial in clinical post cementation. However, hydrogen peroxide etching prior to silanization was not effective in this study.

• 한국식품영양학회지
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• 제11권1호
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• pp.107-113
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• 1998

홍삼의 추출물인 50% ethanol extract, crude saponin, 그리고 lipid soluble fraction이 마우스 대식세포의 oxidative burst를 유발할 수 있는지 여부를 알아보고자 in vitro와 in vivo에 각각의 추출물을 처치하고 hydrogen peroxide 생산을 DCFH-DA를 이용한 형광분광광도법으로 측정하였다. 형광분광법에 의한 hydrogen peroxide의 측정을 최적화하기 위한 DCFH-DA의 농도는 3.2$mu extrm{m}$이었고, oxidative burst를 유도하기 위한 zymosan A, PNA의 최적 농도는 각각 100$\mu\textrm{g}$, 250'기호'를 사용하였다. In vitro의 경우, 홍삼의 3가지 추출물은 모두 oxidative burst를 유발하지 못하였지만, zymosan A로 유발한 경우에는 50% ethanol extract에서 가장 높은 hydrogen peroxide를 생산하였다. In vivo 실험에서는, lipid soluble extract에서만 유의하게 증가한(P<0.01) oxidative burst를 유발하였고, ginsenoside(saponin)가 어느 정도 포함되어 있는 50% ethanol extract와 crude saponin은 대조군에 배하여 유의하게 낮은(P<0.05) hydrogen peroxide를 생산하였다. 이는 ginsenoside가 마우스의 nitric oxide 생산을 억제한다는 다른 연구자들의 보고와 일치하는 결과이다. Oxidative burst를 유발한 lipid soluble extract에는 phenol계 화합물, polyactylence계 화합물, 미량성분 등이 함유되어 있으므로 차후 연구를 통하여 과연 어느 성분이 hydrogen peroxide를 증가시키는지 규명하는 것이 필요하다.