탈기법과 초음파 처리법을 연계한 LPG 지하공동저장소 주변 오염지하수 내 TOC 제거

한이경,전성천,김단우,전소영,이민희 대한자원환경지질학회 2022 자원환경지질 Vol.55 No.5

본 연구에서는 국내에서 운영 중인 대형 LPG(Liquefied petroleum gas: 액화석유가스) 지하공동저장소 주변 오염지하수 내 TOC(total organic carbon: 전유기탄소)를 효과적으로 제거할 수 있는 탈기법(air-stripping) 기반의 정화공정을 개발하기 위해, 국내 LPG 지하저장소 주변 두 종류의 오염 지하수 시료(초기 TOC 농도는 각각 608 mg/L와 153 mg/L)를 대상으로 TOC 제거 실내 실험을 하였다. 다양한 air-stripping 조건(공기주입량 변화, 온도 변화, 초음파 처리 연계 등)에서 처리수의 TOC 제거효율을 비교함으로써, 최적의 TOC 제거효율을 가지는 air-stripping 기반의 지하수 정화공정을 개발하고자 하였다. Air-stripping의 공기 주입량 변화 실험 결과, 공기주입량이 2 L/min에서 11 L/min로 많아질수록, stripping 시간이 1시간에서 24시간으로 길어질수록, 오염지하수의 TOC 제거율은 증가하였지만, 처리 후 지하수의 TOC 농도는 방류수 수질 기준(100 mg/L 이하)보다 높았다. 정성분석 결과 실험에 사용한 LPG 지하저장소 주변 오염지하수의 TOC 주요 성분은 메탄올과 프로판으로 나타났으며, 메탄올의 경우 물과의 친화성에 의해 air-stripping 효과가 프로판보다 낮아, 장시간의 stripping이 필요한 것으로 판단되었다. 상온(20℃)에서 공기주입량 4 L/min로 24시간 air-stripping 후 오염 지하수의 TOC 제거효율은 59.1%였으나, 온도를 30℃와 40℃로 상승 시켰을 때 제거효율은 각각 80.0%와 82.8%로 증가하여, 온도 증가에 따라 TOC 제거효율도 증가하였다. 다만 오염지하수의 온도를 40℃로 유지하여도 24시간 이상 air-stripping을 해야 처리수의 TOC 농도가 방류수 수질 기준을 만족하였다. Air-stripping의 TOC 제거효율을 높이기 위해, 초음파 처리 과정을 병행한 경우, 공기주입량 9 L/min 조건으로 air-stripping을 적용한 결과 5시간 만에 87.8%의 높은 제거효율을 나타내어(처리 후 TOC 농도: 72.4 mg/L) 방류수 수질 기준(100 mg/L)을 만족하였다. 초기 TOC 농도가 낮은 오염지하수의 경우에도 초음파 처리와 air-stripping을 동일한 조건으로 병행한 경우, TOC 제거효율은 89.7%(처리 후 TOC농도: 18.9 mg/L)를 나타내었다. 연구 결과로부터 TOC로 오염된 대형 LPG 지하공동저장소 주변 지하수에 대하여 초음파 처리와 air-stripping을 연계한 정화법을 적용하는 경우, 비교적 짧은 시간(6시간 이하)에 효과적으로 지하수 내 TOC를 제거할 수 있음을 알 수 있었다.

PLVA 방법을 활용한 PR Stripper의 성능 향상과 HDI-PR 표면의 내력 변화 연구

김수인,이창우,Kim, Soo-In,Lee, Chang-Woo 한국진공학회 2008 Applied Science and Convergence Technology Vol.17 No.6

반도체 공정에서 가장 많은 시간과 비용을 차지하는 공정 중 하나는 Photoresist strip 공정이다. 따라서 보다 빠르게 PR의 strip 공정을 단축하기 위한 연구가 계속 진행중에 있다. 하지만 기존 사용중인 strip용액을 대체하기 위한 물질을 찾는 것은 많은 비용을 수반한다. 본 연구에서는 PR의 strip 시간을 최대한 단축시키고 PR strip 잔여물의 빠른 제거를 위하여 기존 공정에서 사용 중인 strip 약액을 플라즈마에 의하여 활성화하는 방법(Plasma Liquid-Vapor Activation: PLVA)으로 PR strip 시간을 최대한 줄이는 방법에 대한 연구를 진행하였으며, 활성화된 strip용액이 더욱 빠른 strip율 성능을 나타내는 것을 확인하였다. 또한 PR strip에서 이온에 의한 영향을 받은 HDI-PR (high dose implanted photoresist)은 기존 strip용액으로 제거가 불가능하였다. 하지만 본 연구에서 제시한 PLVA 방법으로 활성화된 용액에서는 그 가능성을 확인하였고, 이러한 PLVA방법에 대한 물리적 연구를 위하여 HDI-PR 표면 내력의 변화를 측정하였다. 그 결과 PLVA 처리 전 후 HDI-PR의 표면 내력에 큰 변화를 확인하였다. At the semiconductor industry, Photoresist(PR) strip progress has high cost and time consuming process. Accordingly, many research group have been focused on the shortening of the PR strip progress. But the replacements of newly developed materials rather than normally used strip have accompanied by cost consumption. Therefore, we suggested the Plasma Liquid-Vapor Activation (PLVA) method of general PR strip solution for saving the PR strip time and the high strip rate of PR residue. The PLVA method was very effective for PR strip progress. Also, the ion damaged PR(high dose implanted photoresist: HDI-PR) was almost impossible to strip. However, it was very difficult to characterize the change of chemical composition of HDI-PR between with and without PLVA method. Thus, physical properties of HDI-PR surface with and without PLVA method were measured by using the nano-indenter system.

2.6% Hydrogen Peroxide 부착대(strip)의 치아미백효과에 관한 실험실(In vitro) 실험연구

정세환,박덕영,마득상,김지영,김종호 대한구강보건학회 2002 大韓口腔保健學會誌 Vol.26 No.3

A laboratory trial was conducted to evaluate post-treatment color improvement following bleaching with 2.6% hydrogen peroxide containing tooth-whitening strip. Hydroxyapatite tablet(HPT) was made by compressing and sintering 2.5 g hydroxyapatite powder. HPTs were embedded in epoxy resin except active surface. This active surface was stained using Stookey' s methods. Bleaching materials were 2.6% hydrogen peroxide strip, 5,3% hydrogen peroxide strip(Crest^ Whitestips), 2.6% hydrogen peroxide solution, and placebo strip without hydrogen peroxide. HPTs were allocated to each bleaching materials by matching on color grade. After HPTs were treated for 30 minutes at 37℃ and washed and dried, color was measured by Colorimeter CR-321 (Minolta, Japan). The efficacy was evaluated by comparing delta L and delta E_ab values of HPTs surface at baseline and each repeated steps. There was no change of L' value in placebo strip. Each delta L* and delta E'ab values of 2.6% hydrogen peroxide strip, 5.3% hydrogen peroxide strip(Crest Whitestips), and 2.6% hydrogen peroxide solution was increased significantly compared to baseline and placebo strip, respectively (P<0.05). There was no significant change in delta L and delta E_ab values among 2.6% hydrogen peroxide strip, 5.3% hydrogen peroxide strip(Crest^ Whitestips), and 2.6% hydrogen peroxide solution. Whitening effect of 2.6% hydrogen peroxide strip was fairly high compared to 5.3% hydrogen peroxide strip in this in vitro experiment, but further in vivo experiment is needed to prove its efficacy.

『龍崗秦簡』 第1~10簡 연구

이소화(Lee, So-Hwa)(李蘇和),김준수(Kim, Jun-Soo)(金俊秀) 대한중국학회 2020 중국학 Vol.73 No.-

본고는 龍崗秦簡 제1간부터 제10간까지의 내용에 대해 기존의 연구 성과를 토대로 하여 해독을 시도하였으며, 쟁점이 되는 부분에는 상세한 주석을 덧붙이고 고찰을 진행하였다. 주석 작업에 里耶秦簡과 岳麓書院藏秦簡 등 용강진간 이후에 발굴된 최신 秦문자 자료를 적극 활용하였으며, 판독에 어려움이 있는 글자에 대해서는 관련 秦문자와의 자형 비교를 진행해 보다 정확한 考釋에 도움이 되고자 하였다. 용강진간 제1간에서 제10간까지의 내용은 禁苑과 관련된 법률에 대한 기록이다. 금원은 皇家의 가축과 식물들을 기르고 관리하던 정원으로 일반인들의 출입이 엄격히 통제되었다. 따라서 하수도로 몰래 드나들거나 출입증 없이 관문을 지나가면 斬止라는 무거운 형벌에 처해졌으며, 공문서의 관리 역시 엄격한 규정 속에서 이루어졌던 것으로 보인다. This study presents the translation of the first to tenth Longgang Qin Bamboo Strips into Korean based on the findings of preceding studies, along with annotations on the issues worthy of further discussion and related considerations. Longgang Qin Bamboo Strips 1 to 10 contain records about laws related to palace gardens, which can be summarized as follows. A palace garden was a place where livestock and plants belonging to the imperial family were raised and managed, and access by the general public to the garden was prohibited. Therefore, actions such as trespassing on a palace garden through the surrounding sewers, entering it without a valid pass, or forging and borrowing such a pass were considered serious crimes and sentenced to heavy punishments including cutting off the left foot. In addition, all those who needed to enter a palace garden for public affairs had to send an official letter to the competent departments of prefectural and provincial government offices to request entrance to the garden, and the documents sent to these offices must be escalated to higher level agencies. When one enters a palace garden for document delivery or public affairs, he would go through a verification process of the relevant documents, and was required to wear a plaque marked “入司馬門久”‘ while in the garden. In this way, access by the general public to palace gardens was managed in a very strict and restrictive manner. This study analyzed the letters and vocabulary used in Longgang Qin Bamboo Strips by taking full advantage of Qin character documents unearthed after the discovery of Longgang Qin Bamboo Strips such as Liye Qin Bamboo Strips and Qin Bamboo Strips Collected in Yuelu Academy. By collecting and comparing a large amount of Qin character forms, this study also performed a meaningful analysis on the characters that could not be clearly traced back in Longgang Qin Bamboo Strips or pairs of the characters that were difficult to interpret due to similar forms such as 池 (chí) and 事 (shì) in Strip 1, 闌 (lán) in Strip 2, 襲 (xí) and 人 (rén) and 入 (rù) in Strip 4, 佩 (pèi) in Strip 5, 傳 (chuán) in Strip 9, and 作 (zuò) in Strip 10. Based on the appearance pattern of “黔首” (qiánshǒu) in the strips, this study also found a clue to dating the creation of these strips. In addition, it was confirmed that the passages “襲人符傳” (xírénfúzhuàn) and “入門衛木久” (rùménwèimùjiǔ) contained in Longgang Qin Bamboo Strips are also included in Zhangjiashang Han Bamboo Strips. This serves as a good example showing that the Han Dynasty inherited the legal system of the Qin Dynasty. It is expected that this study will be followed by continuous annotation work and studies on Longgang Qin Bamboo Strips and more in-depth research on the strips will be conducted in the future.

압연 공정에서 꼬임 발생 메커니즘에 대한 기초 연구

이창우(Chang Woo Lee),신기현(Kee Hyun Shin),홍완기(Wan Kee Hong),정동택(Dong Taek Jung) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.12

It is very important to find out causes of strip pinching for the high quality of products and for the stable operation of rolling system. We have examined the strip pinching from three points of view to find out the causes of strip pinching in rolling system: strip shape, rolling operation conditions, and behavior of strip. Wedge, off center, and difference of rolling force through CMD(Cross machine direction) are found to possibly provide major initial causes of strip pinching. Generally strip pinching occurred in the tail of strip. Thus, computer simulations by using a FEM code were also carried out to find out the initial mechanism of strip pinching depending upon the force and geometric boundary conditions at the time of strip tail rolling. The strong compression force effect due to the sudden release of strip tail from the work roll and non-uniform strip tail shape (ex. Fish tail) across the CMD were found to provide possible major causes of strip pinching.

Effects of reductive stripping of reactive dyes on the quality of cotton fabric

Mohammad Gias Uddin,Md. Mazedul Islam,Md. Rashedul Islam 한국의류학회 2015 Fashion and Textiles Vol.2 No.1

Some common problems of textile dyeing industries include uneven or faulty dyeing and formation of color patches on the fabric surface during dyeing and downstream processing of textiles materials. Such problems in the finished quality of fabric are generally tackled through a chemical stripping process which is a common practice in dyeing industries for the deep shade batches. However, reactive dyes cannot be stripped satisfactorily from cellulosic materials due to the formation of co-valent bonds between dye and fiber. This research was undertaken using 2.5% and 5% bi-hetero reactive dyes on pretreated cotton fabric and dye stripping was carried out in alkali reductive stripping process. The aim of the work was to investigate the effects of dye stripping on the quality of cotton fabric. Strength loss, weight loss, pilling resistance and absorbency of stripped fabric were calculated. Though with the increase of concentration of stripping chemicals and temperature, stripping percentages were improved; processing damage to the fabric such as losses in strength, weight and pilling resistance ratings was found. In contrast, increased fabric absorbency was found due to stripping. This is explained that during stripping, alkaline solution as an intracrystalline swelling agent is effective in loosening the crystalline region of cotton in addition to the amorphous region. Stripping agent can also attack such crystalline region. As a result, cotton fiber can release maximum number of hydroxyl groups which previously formed covalent bonds. This is the reason behind the stripped fabric having more water absorbency.

치간 법랑질 삭제방법에 따른 치아표면 거칠기에 관한 비교연구

노준,전윤식 대한치과교정학회 1999 대한치과교정학회지 Vol.29 No.4

다양한 부정교합의 원인 중에서 치아의 형태적 이상이나 크기의 부조화를 해결하기 위한 방법으로 치간 법랑질 삭제(interdental enamel stripping)가 임상에서 자주 사용된다. 이런 치간 법랑질 삭제술식은 특히 상하악의 전치부위에서 적은 량의 치아 밀집을 해결하거나, 교정치료 말기에 상하악 치아 크기의 부조화에 의한 견치 또는 구치의 바람직하지 못한 교합관계를 개선하는데 유용하지만 치아삭제가 비가역적인 술식이며, 삭제 후 남게 되는 거친 법랑질 표면으로 인한 치주적 부작용이 문제점으로 지적되어 왔다. 법랑질 삭제 후 표면에 남게 되는 거칠기를 줄이기 위해 다양한 치과용 마모기구를 이용한 방법들이 소개되었지만 그 결과에 대한 해석은 주사현미경(SEM)상에서 관찰되는 표면소견을 통한 비교분석에 국한 되었다. 본 연구의 목적은 임상에서 자주 사용되고 있는 여러 가지 법랑질 삭제방법들의 결과를 주사현미경적 소견과 함께 표면조도측정기를 이용하여 표면의 거칠기를 정량화하므로서 좀 더 구체적인 임상적 결과를 비교 평가하고자 함이다. 치간 법랑질 삭제방법은 기계적 방법 및 기계화학적인 방법으로 나누어 비교하였으며, 기계적 방법은 회전기계삭제와 치과용 마모지를 이용한 삭제로 구분하고, 기계화학적 방법을 위해 37% 인산이 사용되었다. 교정목적으로 발거된소구치의 인접면을 이용하여 기계적 및 기계화학적인 법랑질 삭제방법에 따른 표면 거칠기를 비교 분석한 결과 다음과 같은 결론을 얻었다. 1. 회전기계 및 치과용 마모지를 이용한 기계적 방법으로 1차 삭제한 군의 법랑질 표면이 다른군들에 비해 거칠게 나타났다. 2. 산 부식을 이용한 기계화학적 방법으로 1차 삭제한 군이 기계적 방법으로 1차 삭제한 군에 비해 양호한 표면을 보였다. 3. 기계적으로 1차 및 2차 삭제한 군의 표면은 대조군과 유사한 정도로 표면이 양호하였다. 4. 표면 활택 목적으로 사용된 미세 연마제는 표면 거칠기나 표면의 연마 또는 가공정도에 큰 영향을 주지 않았다. Interdental enamel stripping is an usual method for correction of abnormal tooth shape and tooth size discrepancy which is one of the etiologic factors of malocclusion. Clinically it is useful to correct the minor crowding in anterior teeth and posterior occlusion during finishing stage of orthodontic treatment. But this procedure has risks such as irreversible tooth reduction and remaining roughness of enamel surface can accumulate plaque which can evoke periodontal problem. Even if various methods were introduced to minimize the enamel surface roughness, their evaluation was limited in morphologic differences by scanning electronic microscope(SEM). The purpose of this study was to compare the various interdental enamel stripping method by SEM and to quantify the difference of surface roughness by use of Surfcorder SEF-30D(Kosaka Lab, Ltd.) which can measure the roughness of surface. The stripping methods were divided into mechanical and mechanical-chemical method. Air-rotor stripping and separating strip were used for mechanical stripping and 37% phosphoric acid was used for chemical stripping. The enamel surface roughness after mechanical or mechanical-chemical stripping of interproximal surfaces of premolars which were extracted for orthodontic purpose were measured and compared by means of SEM and Surfcorder, the results were as follows. 1. Enamel surface of primary treated by coarse diamond bur and separating strip groups showed highest value of roughness. 2. To compare the primary treated groups between mechanical and mechanical-chemical method, the latter group showed lower value of roughness remarkably. 3. Mechanical stripping groups which were treated both coarse and fine instrument showed lower value of roughness as much as non treated group. 4. The use of pumice for final polishing did not show significantly smoothening the stripped enamel surface any more.

On the Full Stand Modeling and Tension Control for the Hot Strip Finishing Mill with PID Structure

Ahn, Byoung-Joon,Park, Ju-Yong,Chang, Yu-Shin,Lee, Man-Hyung The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.7

We describe a looper controller design for a hot strip finishing mill in steel plants. The main function of the looper system is to balance the mass flow of the strip by accumulating material in the middle of the stands. Another function is to control the strip tension which influences the width of the strip. To ensure strip quality, it is very important to control the tension of the hot strip finishing mill. However, because there is a mutual interaction between the looper angle and the strip tension, it is difficult to control the looper system. Previous researches examined only the operation of a single stand. But it is not sufficient to examine the operation and effect of whole stands because the operation is wholly interdependent. In this paper, we present a full model of the hot strip finishing mill in order to more effectively control strip tension. We propose several control methods for the full-stand hot strip finishing mill, denoted as conventional PI, PI with cross gain, and coefficient diagram method (CDM) PID control. In the real plants, there are some problems by using higher order controllers such as LQ, LQG and H$\_$$\infty$/. By comparison, the PID controller is very simple and easy to apply to all real plants. To that end, we present our findings on PID controls and their potential use in the hot strip finishing mill.

요시험지 N-Multistix SG-L과 URISCAN Gen 11의 비교

정화령,손향은 凡石學術奬學財團 1999 凡石學術論文集 Vol.3 No.-

리기다소나무림의 대상개벌지내 식재된 상수리나무묘목의 생장특성

박진홍 ( Jin Hong Park ),오광인 ( Kwang In Oh ),안기완 ( Ki Wan An ),김춘식 ( Choon Sig Kim ) 한국산림과학회 2004 한국산림과학회지 Vol.93 No.5

This study was carried out to examine the growth of Quercus acutissima seedlings planted in various levels of strip clear-cutting(uncut, 6m×50m, 10m×50m, 20m×50m) with seedling treatments(fertilization, paper mulching, shelter, Pisolithus tinctorius innoculation, control) in Pinus rigida plantations. The study site was located in Goksung-Gun, Jeollanam-Do. Root collar diameter, height and volume growth of the seedlings differed significantly between various levels of strip clear-cutting and seedling treatments(p<0.05). The growth of seedling root collar diameter was better in the 10m× 50m strip clear-cutting treatment(15.6mm) than in the 20m×50m(14.9mm), 6m× 50m(12.8mm) strip clear-cutting treatments and the uncut treatments(9.8mm). The height of seedling was highest in the 10m×50m strip clear-cutting treatment(121.4cm), followed by the 20m×50m(115.1cm), the 6m×50m(96.9cm) and the uncut treatments(86.4mm). The volume growth of seedlings was also highest in the 10m×50m strip clear-cutting treatment(151.6㎤), followed by the 20m×50m (98.6㎤) and the 6m×50m strip clear-cutting treatments (65.3㎤). Root collar diameter, height and volume growth were superior to fertilization among seedling treatments. Seedling growth in the control did not differ in other seedling treatments such as paper mulching, shelter and P. t. innoculation. Seedling mortality rates were lower in the 6m×50m strip clear-cutting(3.7%) than in the 10m×54m(13.3%) and the 20m×50m strip clear-cutting treatments(15.7%). Also shelter treatments of seedling reduced seedling mortality rates(6.5%) compared with other seedling treatments(>10%). The results indicate that oak regeneration in various levels of strip-clearcutting in Pinus rigida plantations should apply fertilizer with cutting intensity between 10m and 20m strip width.