• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1014-1021
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• 1997

Studies were carried out on the preparation of several kinds of pulps from Sponge gourd fiber by KP, ASP, SP PAP, AP and addition of AQ pulping process. These unbeaten and beaten pulping fibers were observed their characteristics and fiber structure by SEM, FQA, Image analyzer and Micro projector. The results were summarized as follows; 1) The cooking condition which is the possible defibrilation of Shives are KP base($160^{\circ}C$, 2hr.), ASP base($155^{\circ}C$, 4hr.), PAP base($160^{\circ}C$, 1hr.). From the results, the kappa no. had the range of 12, 25, 10 each other. 2) The pulp yields of sponge gourd fiber obtained the range of KP 50~55%, ASP&60~70% and PAP 45~50%. SP base have the highest and contnets of KP&PAP base are much the same as woods. 3) Increasing amount of NaOH on Pulping was accelerated the defibrilation of Shives and was changed a morphology of pulping fiber quality such as fiber length, curl and kink index. 4) Addition of AQ on pulping process of sponge gourd fiber had a affect to raise the rate of delignification while protecting cellullosic components against degradation, especially defibrilation was very excellent, beated pulp much more easily and increased the fibrilation. 5) ASP system have higher bulk density, fiber bonding and protecting cellullosic components against degradation than KP or PAP. 6) The color reactions of the "C" stain solution showed blue or blue-gray with clean and transparency thin cell wall.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.190-190
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• 1999

박막 표면에 대한 경원소 분석법인 탄성 되튐 반도법을 개발하여 수소, 탄소, 질소등 분석에 이용하고 있다. 이때 입사 입자로 Cl 9.6MeV를 이용하였는데, 표적 표면에 탄소막이 흡착되는 현상을 발견하였다. cold trap 및 cold finger를 사용하여 진공도를 개선하므로서, 탄소막 흡착의 한 원인으로 알려져 잇는 chamber 주변의 진공도 변화를 시켜보았다. 하지만 전혀 탄소막이 생기지 않는 10-10torr 이하 진공을 만드는 것은 많은 비용과 장비를 필요로 하는 상당히 힘든 작업이어서, 이차적으로 탄소막이 표적 표면에 달라 붙게 하는 원인으로 추정되는 이차 전자의 발생을 고에너지 이온빔으로 조사하였다. 일반적으로 이차전자의 발생은 이온빔과 표적과의 충돌에 의한 고체 표면으로부터의 전자방출 현상으로 오래전부터 연구되어져 왔다. 여기에는 두가지 다른 구조가 존재하는 것으로 알려져 있다. 그 중 하나는 입사 입자의 전하와 표적 표면사이 작용하는 potential 에너지가 표적 표면의 일함수(재가 function) 보다 클 때에 일어나는 potential emission이다. 즉 표적 궤도에 존재하는 전자와 입사 이온빔 사이의 potential 이 표적의 전자를 들뜨게 만들고, 이 potential의 크기가표적의 표면 장벽 potential 보다 충분히 클 뜸 전자가 방출하는 현상을 말한다. 다른 또 하나의 방출구조로는 입사 이온이 표적 표면의 원자와의 충돌에 의해 직접저인 에너지 전달을 통한 전자 방출을 말하는데, 이를 kienetic emission(이하 KE)이라 한다. 본 연구에서는 Tandem Van de graaff 가속기로 고에너지 이온빔을 만들어 Au에 충돌시키므로서 kinetic emission을 통하여 Au에서 발생한는 이차전자의 방출 수율 및 에너지를 측정하였다.장구조로 전체 성장 양식을 예견할 수 있다. 일반적인 경향은 Ep가 커질수록 fractal 성장형태가 되며, Ed가 적을수록 cluster 밀도가 작아지나, 같은 Ed+Ep에 대해서는 동일한 크기의 팔 넓이(수평 수직 방향 cluster 두께)를 가진다. 따라서 실험으로부터 얻은 cluster의 팔 넓이로부터 Ed+Ep 값을 결정할 수 있고, cluster 밀도와 fractal 차원으로부터 각각 Ed와 Ep값을 분리하여 얻을 수 있다. 또한 다층 성장에 대한 거칠기(roughness) 값으로부터 Es값도 구할 수 있다. 양방향 대칭성을 갖지 않은 fcc(110) 표면과 같은 경우, 형태는 다양하지만 동일한 방법으로 추정이 가능하다. (110) 표면의 경우 nearest neighbor 원자가 한 축으로 형성되고 따라서 이 축과 이것과 수직인 축에 대한 상호작용이나 분산 장벽 모두가 비대칭적이다. 따라서 분산 장벽도 x-축, y-축 방향에 따라 분리하여 Edx, E요, Epx, Epy 등과 같이 방향에 따라 다르게 고려해야 한다. 이러한 비대칭적인 분산 장벽을 고려하여 KMC 시뮬레이션을 수행하면 수평축과 수직축의 분산 장벽의 비에 따라 cluster의 두께비가 달라지는 성장을 볼 수 있었고, 한 축 방향으로의 팔 넓이는 fcc(100) 표면의 경우 동일한 Ed+Ep값에 대응하는 팔 넓이와 거의 동일한 결과가 나타나는 것을 볼 수 있다. 따라서 이러한 비대칭적인 모양을 가지는 성장의 경우도 cluster 밀도, cluster 모양, cluster의 양 축 방향 길이 비, 양 축 방향의 평균 팔 넓이로부터 각 축 방향의 분산 장벽을 얻어낼 수 있을 것으로 보인다. 기대할 수 있는 여러 장점들을 보고하고자 한다.성이 우수한 시편일수록 grain의 크기가 큰 것으로 나타났고 결정성이 우수한 시편의 경우에서는 XR

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.269-276
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• 2007

$TiO_2$-containing pitch fibers were prepared and various stabilization variables were investigated by characterizations of the fibers and behaviors of $TiO_2$ particles in the optimum stabilization conditions. When pitch fiber was stabilized by air at the optimum condition, the fiber weight increased as an increase of the stabilization temperature and a decrease of $TiO_2$ concentration. The carbonization yield was 71~82 wt.%, showing a decrease of the yield with the $TiO_2$ increase caused by the catalytic activity of $TiO_2$ to combustion. During the stabilization, newly developed carbonyl and carboxyl groups were introduced on the fiber surface and cross-linking reactions were progressed resulting the thermosetting property, which was verified by the replacement of hydrogen with oxygen. Pore size of the activated carbon fiber was increased by an increase in $TiO_2$ concentration. In the considerations of the aggregation behaviors of the $TiO_2$ particles, the optimum stabilization conditions of 0.5 wt.% $TiO_2$ containing petroleum-based pitch fiber were suggested as $280^{\circ}C$, 3 hr.

• Food Science and Preservation
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• v.11 no.1
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• pp.100-105
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• 2004

The objective of this study was carried out to investigate biological activities effects of Korean leaf from Rosa davurica Pall. in vitro. They were extracted with methanol, ethanol, chloroform and water. Methods of the antimutagenic used in this experiment were well-known bacterial short term tests which include Ames test and the antigenotoxic used in this experiment was DPPH radical scavenge. All extracts (ethanol, methanol, water) except chloroform extract exhibited 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity with IC$\_$50/ of 11.5 $\mu\textrm{g}$/mL, 6.4 $\mu\textrm{g}$/mL, 4.8 $\mu\textrm{g}$/mL. In Ames test, most of extracts had strong antimutagenic effects against the mutagenesis induced by 4-nitroquinoline-1-oxide (4NQO), N-methyl-N’-nitro-N-nitrosoguanidine (MNNG), 3-amino-l,4-dimethyl-5H-pyrido[4,3-b]indol(Trp-P-I) and benzo(${\alpha}$)pyrene(B(${\alpha}$)P). The extracts of leaves (200 $\mu\textrm{g}$/plate) showed approximately 60∼80％ inhibitory effect on the mutagenesis induced by 4NQO, Trp-P-1 and B(${\alpha}$)P against TA98 strain, whereas 60∼80％ inhibition were observed on the mutagenesis induced by MNNG, 4NQO, Trp-P-1 and B(${\alpha}$)P against TA100 strain. respectively.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.297-302
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• 2019

In order to investigate structural changes of the pyrolysis fuel oil (PFO), the volatile matters and heavy oil fractions were separated from PFO by heat treatment temperature. As a result of $^1H-NMR$ analysis of volatile matters, 1~2 ring aromatic compounds contained in the petroleum residue were mostly removed at a temperature before $340^{\circ}C$. Moreover, new peaks corresponding to aliphatic hydrocarbons were detected at the chemical shift of 2.0~2.4 ppm. It is attributed that the aliphatic hydrocarbon sidechain was cracked from the aromatic compound by the cracking reaction occurred at $320^{\circ}C$. The C/H mole ratio and aromaticity increased with increasing the heat treatment temperature. Therefore, from the structural analysis results of heavy oil fractions and volatile matters from PFO, the decomposition of the aliphatic sidechain by cracking reaction and the separation of volatile matters by boiling point of components were mostly affected structure changes of the PFO.

• Clean Technology
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• v.29 no.3
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• pp.185-192
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• 2023

This study was conducted to obtain basic process simulation data before conducting pyrolysis experiments for the development of a thermochemical conversion system by recirculation of heat carrier and gases thereby. In this study, polypropylene (PP) was used as a pyrolysis sample material as an alternative to waste plastics, and fluid sand was used as a heat transfer medium in the system. Manganese (Mn) was chosen as the catalyst for the pyrolysis experiment, and the catalyst pyrolysis was performed by impregnating it in the sand. The basic properties of PP were analyzed using a thermogravimetric analyzer (TGA), and liquid oil was generated through catalytic pyrolysis under a nitrogen atmosphere at 600℃. The carbon number distribution of the generated liquid oil was confirmed by GC/MS analysis. In this study, the effects of the presence and the amount of Mn loading on the yield of liquid oil and the distribution of hydrocarbons in the oil were investigated. When Mn/sand was used, the residue decreased and the oil yield increased compared to pyrolysis using sand alone. In addition, as the Mn loading increased, the ratio of C₆~C₉ range gasoline in the liquid oil gradually increased, and the distribution of diesel and heavy oil with more carbon atoms than C₁₀ in the oil decreased. In conclusion, it was found that using Mn as a catalyst and changing the amount of Mn could increase the yield of liquid oil and increase the gasoline ratio in the product.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.117-123
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• 2007

The effect of aluminium addition to MCM-41 on product yield and carbon number distribution was investigated in the catalytic cracking of a polymer mixture, LDPE, LLDPE, and EVA copolymer, with a composition similar to that found in real agricultural film wastes. Al-MCM-41 catalyst synthesized by post-synthetic grafting method (Al-MCM-41-P) as well as Al-MCM-41 catalyst synthesized by direct sol-gel (Al-MCM-41-D). The catalytic cracking of polymer mixture was carried out in vapor phase contact as well as in liquid phase contact. The amount of acid sites increased with aluminium addition by post method as well as direct method, which was seemed to be due to Lewis acid sites. In liquid phase catalytic cracking, the yield of light hydrocarbon fraction increased with aluminium addition. The effect of aluminium addition on production of $C_5-C_{12}$ hydrocarbons over Al-MCM-41-P catalysts was greater than that over Al-MCM-41-D catalysts. In the case of vapor phase catalytic cracking, the effect of aluminium addition was smaller than that of liquid phase catalytic cracking. The selectivity to $C_{13}-C_{32}$ hydrocarbons was smaller in vapor phase catalytic cracking.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.521-529
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• 2011

Methanol-to-olefin (MTO) reaction was studied over MWW zeolite with independently developed two pores (circular and straight) and MFI zeolite with intercrossed sinusoidal and straight pores in order to investigate the effect of pore structure on their catalytic behavior. MWW and MFI zeolites with similar acidity exhibited commonly high conversion and slow deactivation in the MTO reaction, but their product selectivities were considerably different: linear hydrocarbons of $C_3-C_9$ were mainly produced on MWW, while the yield of $C_2{^=}$ and aromatics were high on MFI. Polyaroamatic hydrocarbons (PAHs) were accumulated on MWW, but a small amount of benzene and aromatics on MFI. The impregnation of phosphorous on MWW caused significant decreases in the catalytic activity and toluene adsorption, but the decreases were relatively small on MFI. Although the straight pores of MWW were inactive in the MTO reaction due to the accumulation of PAHs, its circular pores which suppressed the formation of PAHs sustained catalytic activity for the production of linear hydrocarbons. Therefore, the impregnation of phosphorous on the circular pores of MWW caused a significant decrease in catalytic activity. The phosphorous impregnation on the cross sections of MFI altered the product selectivity due to the neutralization of strong acid sites, but catalytic deactivation was negligible. The difference of MWW and MFI zeolites in the MTO reaction was explained by their difference in pore structure.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.865-875
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• 2018

Selection of optimum reaction conditions during deoxygenation process of palm oil is essential factor to obtain the maximum yield of bio-jet fuel. In this context, the deoxygenation of palm oil was carried out in a fixed bed reactor with an internal diameter of 1 inch loaded with a 1 wt.% $Pt/Al_2O_3$ catalyst. The composition of the organic liquid product(OLP), which can be utilized as a transportation fuel through the upgrading process, was analyzed by a gas chromatography method. The palm oil/hydrogen ratio and hydrogen pressure in the feed affected the decarboxylation(DCB) and hydrodeoxygenation(HDO) reactions, resulting in a change in the composition of the OLP. As the reaction temperature increased, the continuous cracking reaction of the deoxygenation product was promoted and the product composition in the $C_5{\sim}C_{14}$ region was increased. Thus, the results can help to understand the characteristics of deoxidation reaction of palm oil as well as the subsequent process, hydro-upgrading, to obtain the maximum yield of bio-jet fuel.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.824-830
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• 2015

The influence of phosphorous precursors, $NH_4H_2PO_4$, $(NH_4)_2HPO_4$, $H_3PO_4$, $(C_2H_5)_3PO_4$, and $P_2O_5$, on the catalytic performance of the $BiFe_{0.65}MoP_{0.1}$ catalysts in the oxidative dehydrogenation of 1-butene to 1,3-butadiene was studied. The catalysts were characterized by XRD, $N_2$-sorption, ICP, SEM and TPRO analyses. It was not observed big difference on the physical properties of catalysts in accordance with used different phosphorous precursors, however, the catalytic performance was largely depended on the nature of the phosphorous precursors. Of various precursors, the $BiFe_{0.65}MoP_{0.1}$ oxide catalyst, which was prepared from a phosphoric acid precursor, showed the best catalytic performance. Conversion and yield to butadiene of the catalyst showed 79.5% and 67.7%, respectively, after 14 h on stream. The cation of phosphorous precursors was speculated to affect the lattice structure of the catalysts during catalyst preparation and this difference was influenced on the re-oxidation ability of the catalysts. Based on the results of TPRO, it was proposed that the catalytic performance could be correlated with re-oxidation ability of the catalysts.