• Journal of Chest Surgery
• /
• v.28 no.11
• /
• pp.1032-1037
• /
• 1995

Between September 1988 and December 1993, 32 cases of benign esophageal stricture, of which 12 males and 20 females, were managed in Seoul National University Hospital hospital. Their age ranged from 2 to 61 years, and the mean age was 33.9 years. The ingestion of caustic agent was the most common cause, and the caustic material was acid in 16 patients [58% and alkali in 11patients [39% . Nearly all of the patients complained of dysphagia, and some of chest pain, epigastric pain, weight loss, vomiting, general malaise, and dyspnea. The most frequent site of stricture was found in the upper thoracic esophagus with 34% incidence followed by the lower thoracic esophagus[28% , whole esophagus[19% , and the mid esophagus[16% . The operations performed were 17[53% ECG[esophagocologastrostomy , 5[16% PCG[pharyngocologastrostomy , 5[16% EG[esophagogastrostomy , 2 EJG [esophagojejunogastrostormy by free jejunal graft , and 1 case each of EJ [esophagojejunostomy , esophageal end to end anastomosis, jejunostomy only, and gastrostomy only. In 23 patients [72% , diseased esophaguses were resected, using transhiatal total esophagectomy in 15 [47% and transthoracic partial esophagectomy in 8 [25% . Of those 23 patients, 3 patients [9.4% were diagnosed as esophageal carsinoma on microscopic examination. The postoperative most common complications were unilateral vocal cord palsy in 6 patients [19% , followed by cervical anastomosis leakage in 4 patients [12.5% , wound infection in 2 patients [6% , and pneumothorax in 2 patients [6% . Late death occurred 8 months after the operation in one patient, which was associated with infection due to anastomotic leakage. Our experience shows that the rate of mortality and the morbidity were low in patients receiving surgical management for esophageal stricture and that the cancer transformation rate was high. We recommend esophageal reconstruction surgery with esophagectomy [transhiatal or transthoracic for the esophageal stricture because it can avoid a chance of prevent cancer transformation.

• Elastomers and Composites
• /
• v.35 no.4
• /
• pp.288-295
• /
• 2000

It has been tried to decrease the crosslink density of vulcanized EPDM (ethylone-propylene-diene terpolymer) rubber through a chemical devulcanization treatment. Phase transfer catalyst, alkali metal (i.e., sodium), and triphenylphosphine have been used as a chemical agent ul the devulcanization treatment. Also it has been estimated the effect of the devulcanization treatment in the case of utilization of 2-butanol as a devulcanization reaction solvent. In the devulcanization treatment using quaternary ammonium salt as a phase transfer catalyst. the devulcanization effect has been studied with the variation of catalyst molecular weight and the choice of bromide or chloride cation. In the devulcanization treatment using sodium, it has been estimated the devulcanization treatment effect depending upon the variation of reaction variables such as amount of sodium used, reaction temperature, pressure of hydrogen gas, which is used as a reaction environment. The $M_c$ value (number average molecular weight between two crosslink points) has been experimentally estimated by the equilibrium swelling method and it is quantitatively related to the crosslink density. The estimation of devulcanization effect for vulcanized EPDM rubber has been carried out by the comparison of the $M_c$ values between the untreated and the treated specimens.

• Fashion & Textile Research Journal
• /
• v.13 no.5
• /
• pp.797-805
• /
• 2011

This study was carried out to investigate dyeing characteristics of CDP(cation dyeable polyester)/silk knitted fabrics with disperse type cation dyes/acid dyes by one bath dyeing method in comparison with two bath dyeing method in the interests for rationalization of the dyeing process. The apparent color depth(K/S) of the disperse type cation dyes with CDP and that of acid dyes with silk decreased slowly with increasing pH values of dyebath with the exception of sharp decrease at alkali region for CDP. The contamination behavior of CDP by the acid dyes and that of silk by the disperse type cation dyes decreased with progressing of dyeing. The migration ratio(%) of the disperse type cation dyes with CDP is low compared with that of acid dyes with silk. The sediment in mixed dying solution of disperse type cation dyes and acid dyes remarkably less compared with that of regular type cation dyes and acid dyes at $100^{\circ}C$ regardless applying of preventer agent of precipitation. When CDP/silk knitted fabrics was dyed with by with mixtures of disperse type cation dyes/acid dyes one bath or two bath dyeing method, the characteristic of reflectance spectra of CDP components were greatly influenced by disperse type cation dyes and that of silk components by acid dyes. It was confirmed that K/S values of each components of CDP/silk knitted fabrics dyed by one bath dyeing method decreased slightly compared with two bath dyeing method.

• Applied Chemistry for Engineering
• /
• v.3 no.4
• /
• pp.710-716
• /
• 1992

Ethylphenyl carbarmate(EPC) was synthesized by oxidative CO carbonylation of aniline in the presence of transition metal catalysts and alkali metal halide cocatalysts at $120^{\circ}C$ under the pressure of 79atm. Oxygen gas was used for oxidizing agent. Kinetics of the reaction was studied and activation energies with different catalysts were estimated. About 100% conversion to EPC and 95% selectivity was obtained in 5 hour reaction. 5% Pd/C was more effective than 5% Rh/C. Effectiveness of cocatalysts was in the order of KI>KBr>KCl. As the temperature increased from $75^{\circ}C$ to $120^{\circ}C$, the conversion rate increased. The reaction was apparent first order and the activation energies with 5% Pd/C and 5% Rh/C were 5.647 and 5.780 kcal/mol, respectively.

• Corrosion Science and Technology
• /
• v.15 no.6
• /
• pp.303-310
• /
• 2016

The tap water used in Seoul was found to be corrosive. Its corrosivity was effectively reduced by that the additions of alkali agent such as NaOH, $Ca(OH)_2$ and corrosion inhibitor such as $H_3PO_4$. For the corrosion test, carbon steel pipe 50 m long was exposed to the drinking water produced by a pilot plant at $36.5^{\circ}C$, similar to the existing process where it takes about 20 minutes to reduce the initial chlorine content of 0.5 mg/L to 0.05 mg/L. $CO_2$ and $Ca(OH)_2$ was added not only to control the Langelier index (LI) above -1.0 and but also, to increase the duration time of residual chlorine by about 6 times. The persistence effect of residual chlorine was in the order of $H_3PO_4$ > $Ca(OH)_2$ > NaOH. Measurements of weight loss showed that corrosion inhibition was effective in order of $Ca(OH)_2$ > $H_3PO_4$ > NaOH > no addition, where the concentrations of $Ca(OH)_2$ and phosphate were 5 ~ 10 mg/L (as $Ca^{2+}$) and 1 mg/L (as $PO{_4}^{3-}$), respectively.

• Journal of Pharmaceutical Investigation
• /
• v.34 no.4
• /
• pp.269-274
• /
• 2004

To enhance the solubility and stability of lansoprazole (LAN), new proton pump inhibitor, we were prepared various molar ratio of inclusion complex with $2-hydroxypropyl-{\beta}-cyclodextrin$ (HPCD) and organic alkali agent, meglumine (MEG). Inclusion complex formation of LAN with HPCD was investigated by Differential Scanning Calorimetry and X-ray diffractometry. The aqueous solubilities of inclusion complexes, and the stabilities of 1:4 and 1:5 inclusion complexes in aqueous solutions containing different concentrations of MEG were examined. The stability of 1:5 LAN-HPCD inclusion complex containing MEG, which was equaled to amount of LAN, was performed in 0.9% NaCl and 5% dextrose solution. The formation of inclusion complex of LAN with HPCD was $A_L$ type and the molar ratio of complex was 1:1. The stability constant was $41.557\;M^{-1}$. As molar ratio of LAN to HPCD was increased, solubility of inclusion complex was increased. 1:5 LAN-HPCD inclusion complex was more stable than 1:4 LAN-HPCD inclusion complex. And as contained MEG amount in LAN solution was increased, stability of 1:4 and 1:5 LAN-HPCD inclusion complexes was improved. Also stability of 1:5 LAN-HPCD-MEG inclusion complex in 0.9% NaCl solution and 5% dextrose solution was similar to it in water at room temperature, but it was unstable at $40^{\circ}C$.

• Korean Journal of Plant Resources
• /
• v.12 no.4
• /
• pp.289-296
• /
• 1999

The availability of Bacillus polimyxa 'HB 26-5' as a biological control agent was investigated. The antagonistic bacteria Bacillus polymyxa 'HB 26-5' grew well on the media at pH 7.0 and the optimum growth temperature was $25^{\circ}C$. The pH of the media changed to weak acid(pH 6.1~6.5) at the beginning of incubation, but to weak alkali(pH 7.8~8.2) at 7days after incubation. The best carrier to enhance colonization of the bacteria were the mixture of rice bran and peat, or rice bran and kaoline, in those formulation the density of the bacteria was changed slightly, though the density was beginning to decrease 3 weeks after application at field. In view of the physical characteristics of the formulation for the density maintenance during storage such as the hardness and the size, the best one was the formulation consisted of sodium alginate 2%, kaolin 15% and rice bran 3%.

• The Research Journal of the Costume Culture
• /
• v.31 no.2
• /
• pp.161-172
• /
• 2023

In this study, natural dyeing using Polygonum tinctoria was performed with linen, ramie, and hemp, which are biodegradable cellulose fibers, considering environmental aspects. In particular, the impacts of alkali NaOH and reducing agent Na₂S₂O₄ were examined, and the possibilities of minimizing the use and reusing the dye were explored. The surface dye concentrations were found to be in the following order: hemp>linen>ramie. With the increase in all additives, the L^* value decreased, and the ⊿E and K/S values increased gradually. When Na₂S₂O₄ was 1g/L, the surface color of the dye appeared uniformly from the NaOH concentration of 0.4g/L (pH 10.84). When NaOH was 0.4g/L, the K/S values of linen and ramie increased rapidly after 0.4g/L of Na₂S₂O₄, and hemp maintained a stable color from 0.6g/L of Na₂S₂O₄. With the increase in the dye concentration from 1 to 6g/L, all the fibers were dyed uniformly. The K/S value increased or higher doubled upon repeated dyeing six times for 5 min than when dyed only once for 30 min. Therefore, the linen, ramie, and hemp fibers dyed repeatedly exhibited good washing, rubbing, and colorfastness to perspiration, which was rated between 4 and 4-5, and that to light was rated as 5. Moreover, no discoloration due to sunlight was observed. Finally, linen exhibited a bacterial reduction of 99.9%, thereby indicating its excellent antibacterial property.

• Corrosion Science and Technology
• /
• v.22 no.3
• /
• pp.187-192
• /
• 2023

The use of biomass is increasing as a response to the convention on climate change. In Korea, a method applied to replace fossil fuels is using wood chips in a cogeneration plant. To remove air pollutants generated by burning wood chips, a selective denitrification facility (Selective catalytic reduction, SCR) is installed downstream. However, problems such as ash deposition and descaling of the equipment surface have been reported. The cause is thought to be unreacted ammonia slip caused by ammonia ions injected into the reducing agent and metal corrosion caused by an acidic environment. Element analysis confirmed that ash contained alkali metals and sulfur that could cause catalyst poisoning, leading to an increase in the size of ash particle and deposition. Measurement of the size of ash deposited inside the facility confirmed that the size of ash deposited on the catalyst was approximately three times larger than the size of generally formed ash. Therefore, it was concluded that a reduction in pore area of the catalyst by ash deposition on the surface of the catalyst could lead to a problem of increasing differential pressure in a denitrification facility.

• Applied Chemistry for Engineering
• /
• v.4 no.4
• /
• pp.760-769
• /
• 1993

Solvent-free low foaming scouring agents(LFSA) were prepared by blending of polyoxyethylene(30) octadecylbenzylammonium chloride(POAC), block copolymer of propylene oxide-ethylene oxide[p(PO-b-EO) glycol], Sedlan FF-200(FF-200) and sulfonic acid-amine condensate of polyoxyethylene(10) nonylphenyl ether(PSAC). In consequence of several tests, FF-200/POAC/p(PO-b-EO) glycol/PSAC/water (20g/10g/5g/5g/60g) mixture (LFSA-5) showed good cleaning power, penetrating ability, emulsifiability and stability to alkali, and gave less problem in water pollution. Scouring effect of LFSA-5 was investigated by the change of percentage of exhaustion before and after scouring at various dyeing temperatures. The percentage of exhaustion of the unscoured PET fabric was 4.5% at $70^{\circ}C$, while that scoured with LFSA-5 was 1.3% at the same temperature, which proved LFSA-5 to be a good scouring agent. Moreover, the foaming power of LFSA-5 measured by Ross and Miles method was 6mm foam height immediately after foaming, and that measured by Ross and Clark method was less than 300mm foam height at $30^{\circ}C$, and 20mm at $80^{\circ}C$. As a result, LFSA-5 proved a good low foaming scouring agent.