• 제목/요약/키워드: the year of chemistry

검색결과 380건 처리시간 0.032초

Analyzing Safety Culture in Sri Lankan Industrial Chemical Laboratories

  • Samaranayake, Ashen I.;Nishadya, Sajani;Jayasundara, Udaya K.
    • Safety and Health at Work
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    • 제13권1호
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    • pp.86-92
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    • 2022
  • Background: A laboratory where chemicals are handled can be considered a hazardous environment, and hence, prudent practices should be strictly enforced. If not, deadly accidents and incidents could occur due to a lack of safety practices and poor safety culture. The purpose of this study is to analyze the existing safety culture and propose potential recommendations to enhance the level of safety education in the chemical laboratories in the Western Province of Sri Lanka. Methods: A survey questionnaire was administered among the laboratory supervisors of the chemical laboratories in the Western Province of Sri Lanka in 2019. Results: Even though 80 surveys were distributed among prospective participants, only 46 surveys were submitted, which is 58% of the response rate. Most of the individuals who participated in the survey were females below 35 years old, and approximately 96% of the participants had at least one year of working experience in the same laboratory setting. The majority considered safety as an important factor that requires further improvements with third-party safety inspections; however, 54% of the respondents mentioned that those inspections were conducted by the employees from their laboratory. Conclusion: From the study, it has been discovered that employees have knowledge of safety culture to a certain extent. A significant percentage (83%) of participants believed that further safety measures are required for a safer laboratory. However, the study revealed that the attitudes of some employees should be changed to have a better safety culture. Hence the authors would like to suggest having annual training sessions and well-formulated safety policies to improve the safety culture.

토양유기물 함량이 인삼근의 endosulfan 흡수이행에 미치는 영향 (Effect of soil organic matter content on plant uptake factor of ginseng for endosulfan)

  • 오경열;최근형;배지연;이득영;이성우;김진효
    • Journal of Applied Biological Chemistry
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    • 제63권4호
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    • pp.401-406
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    • 2020
  • 본 연구에서는 경작지 포장 조사를 통한 인삼근의 endosulfan 흡수이행성(PUF)을 산출하고, 토양 유기물 함량과 endosulfan에 대한 인삼근의 PUF에 관한 상관성을 분석하였다. Endosulfan 흡수이행 시험포장의 총 endosulfan 잔류량은 0.013-0.136 mg kg-1이었다. Endosulfan에 대한 인삼근의 PUF는 0.243-1.708로 인삼근의 연령이 증가할수록 비대생장에 의한 PUF값 감소가 확인되었다. 또한, 토양 유기물 함량과 endosulfan에 대한 인삼근의 PUF값은 5% 유의수준에서 음의 상관관계가 있음을 확인하였다(R2=0.6102). 따라서, endosulfan 오염 우려지역에서의 인삼경작을 위해서는 가급적 높은 토양유기물 함량을 유지하는 것이 endosulfan의 흡수이행을 억제하는데 도움을 줄 수 있을 것이다.

대학수학능력시험 화학II 문항에 대한 학생들의 응답 분석 (Analysis of Students' Responses on the Items of Chemistry II in the College Scholastics Ability Test)

  • 홍미영;전경문;이범홍;이양락
    • 한국과학교육학회지
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    • 제22권1호
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    • pp.204-213
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    • 2002
  • 1999학년도부터 지난 3년 동안 시행된 대학수학능력 시험에서 화학 II 문항에 대한 학생들의 응답을 조사하였다. 화학 II에 대한 응시자수와 평균 점수, 내용 영역과 탐구 과정에 의한 평균 정답률, 정답률이 높거나 낮은 문항 등을 분석 논의하였다. 자연계 응시자는 해마다 감소하고 있으나, 자연계 학생 중 25% 이상이 화학 II를 선택하며, 이는 생물 II에 이어 두 번째로 많은 수이다. 2001학년도에는 화학 II의 평균점수가 높아졌는데, 다른 과목들도 마찬가지였다. 내용 영역이나 탐구 과정에 의한 평균 정답률의 차이는 없었다. 학생들은 '끓는점오름'이나 '삼투압'과 같은'용액의 총괄성'과 관련된 문제를 어려워하였고, '반응 속도'와 관련된 문제를 비교적 잘 해결하였다. 교육학적 함의에 대해 논의하였다.

숙신산 알킬 하프-아마이드 유도체의 합성 및 해수에 대한 방청성능 (Synthesis and Anti-corrosion Properties of Succinic Acid Alkyl Half-amide Derivatives)

  • 백승엽;김영운;정근우;유승현;김남균
    • 청정기술
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    • 제17권4호
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    • pp.314-324
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    • 2011
  • 아마이드 유도체는 방청성능 및 윤활성능이 우수하여 금속가공유 및 유압작동유등의 첨가제로 많이 사용되고 있다. 본 연구에서는 광유계 윤활기유의 방청제로 사용하기 위하여 알킬 무수 숙신산과 여러 가지 아민과의 링개환 반응을 행하여 카르복실 그룹과 아마이드 그룹을 동시에 포함하는 숙신산 알킬 하프-아마이드 유도체들을 97% 이상의 수율로 합성하였으며 합성구조에 따라 1 중량% 농도범위에서 광유계 오일에 용해되었다. 합성 유도체의 구조는 $^1H$-NMR 및 FT-IR 스펙트럼으로 행하였으며 GC 크로마토그램을 통하여 화합물의 순도를 확인하였다. 또한, 합성 유도체의 해수에 대한 방청성능을 ASTM D665 표준방법과 무게 중량법으로 평가한 결과, 합성 유도체의 농도가 증가하고 알킬기의 사슬이 짧고 2차 아민으로 합성한 숙신산 알킬 하프-아마이드의 방청성능이 1차 아민으로 합성한 유도체보다 상대적으로 방청성능이 우수하였다. 무게 중량법으로 평가한 방청효율% (IE%)는 알킬기의 사슬이 짧을수록 우수한 방청효율을 나타내었으며 구조에 따라 방청효율에 차이를 나타내었다. 40 ppm 농도를 첨가한 오일의 IE%는 최고 93% 이상이었다. 또한, 발청속도(Corrosion Rate, CR)는 알킬기의 사슬이 짧을수록 낮은 값을 나타내어 합성 유도체 40 ppm 농도를 첨가한 오일의 CR 값은 최고 0.5 mm/year 이하로 나타났다.

한국 어린이와 청소년의 요중 크레아티닌 농도와 영향요인에 대한 연구 (Factors Associated with the Concentrations of Urinary Creatinine in Korean Children and Adolescents)

  • 이진헌;안령미;강희숙;최석남;홍춘표;김진경
    • 한국환경보건학회지
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    • 제38권4호
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    • pp.291-299
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    • 2012
  • Creatinine-adjustment is an important process in the urinary monitoring of the environmental exposure of children and adolescents. The purpose of this study was to investigate the concentrations of urinary creatinine and factors associated with them among Korean children and adolescents. We recruited 1,025 persons from 128 extracted schools. They were from three to 18 years old and supplied urine samples for measuring creatinine. The concentrations of urinary creatinine were 98.18 mg/dl (SD, 67.67) in arithmetic mean and 72.05 mg/dl (GSD 2.49) in geometric mean, were significantly higher among male children/adolescents than females in all age groups, and higher values appeared following increasing ages, heights and BMIs. The rates of the number who were below the lowest limit recommended by WHO (<30 mg/dl) were 25.57% among three to four year olds, 21.77% among five to six year olds, 20.0% among seven to eight year olds and 14.69% among nine to ten year olds, respectively. The rates of those above the highest limit (>300 mg/dl) were 0.0% among three to twelve year olds. The coefficient of determination R-square of the fitted regression model for urinary creatinine was 27.4% with general characteristic variables of sex, age, BMI and height. The significant variables among these were height (standardized beta = 0.372) and age (standardized beta = 0.129). Another coefficient of determination R-square was 15.3% with dietary habit variables of smoking, drinking, dining area, number of meals and snacks, and intake of milk food, cup-noodles, canned foods, popcorn, nachos, and hamburgers. In conclusion, the concentration of urinary creatinine was significantly lower in children than in adults, and was very significantly associated with the height of children. Therefore, children need the recommended concentrations for urinary creatinine, as distinguished from adults.

제주도(濟州道)의 감귤(柑橘)및 감귤원토양(柑橘園土壤)에 관(關)한 잔류농약조사(殘留農藥調査) - 제2보(第二報), 감귤원(柑橘園) 토양중(土壤中)의 농약잔류(農藥殘留)에 관(關)하여 - (A Survey of Pesticide Residues of Citrus Fruits and Citrus Orchard Soil in Jeju Island - Part 2. On the Pesticide Residue of Citrus Orchard Soil -)

  • 이규승
    • Applied Biological Chemistry
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    • 제23권3호
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    • pp.184-188
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    • 1980
  • 감귤원토양중 잔류하는 농약성분과 구리함량을 알아보기 위해 1979년 10월말부터 1980년 6월초까지 남제주군 서귀읍 일원에서 실험을 실시하였다. 토양시료는 감귤원의 개원년수에 따라 각각 5년, 10년, 15년, 20년 및 30년된 과원을 임의로 선정하여 각 10점씩 채취하였으며, 각 시료는 다시 토심에 따라 $0{\sim}10cm,\;10{\sim}20cm$, 그리고 $20{\sim}40cm$로 나누어 조사하였다. 실험결과를 요약하면 아래와 같다. 1. 모든 시료에서 유기염소제 살비제인 Kelthane과 Akar 및 구리를 검출할 수 있었으며, Kelthane의 잔류량이 Akar에 비해 높은 수준을 나타냈다. 2. Kelthane, Akar 및 구리의 잔류량은 감귤원의 재배년한에 비례하여 증가하였으며, 토심이 깊어짐에 따라 낮아지는 경향을 보여주었다. 3. Kelthane의 잔류수준은 $trace\;{\sim}l.359ppm$이었으며 조사된 토양전충에 대한 총 잔류량을 5년차 감률원은 0.274ppm, 10년차는 0.441ppm, 15년차는 0.758ppm, 20년차는 0.975ppm, 그리고 30년 이상은 1.310ppm이었으며, 토심별 평균 잔류량은 표층토가 0.327ppm, 중층토가 0.236ppm 그리고, 심층토가 0.189ppm이었고, 총 평균잔류량은 0.25ppm이었다. 4. Akar의 잔류수준은 $trace\;{\sim}0.925ppm$이 었고, 전충토양에 대한 총 잔류량은 5년차가 0.082ppm, 10년차가 0.135ppm, 15년차는 0.178ppm 20년차는 0.591ppm, 그리고 30년 이상은 0.818ppm이었으며, 토심별 평균 잔류량은 표층토가 0.163ppm, 중층토가 0.113ppm 그리고 심층토가 0.085ppm을 나타냈으며 총 평균잔류량은 0.120ppm이었다. 5. 토양중 구리함량은 $trace\;{\sim}40.734ppm$ 범위이었으며 전충토양중의 총 잔류량은 5년차는 2.980ppm, 10년차는 3.300ppm, 15년차는 4.808ppm, 20년차는 8.434ppm, 그리고 30년 이상은 13.001ppm의 수준이었고 토심별로는 표층토 3.187ppm, 중층토 1.732ppm, 그리고 심층토는 1.585ppm을 나타냈으며 총 평균 잔류량은 2.168ppm이었다.

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Annual Cycle of the Seminiferous Epithelium of Miniopterus schreibersi fuliginosus

  • Kang Mu-Shik;Lee Jung-Hun
    • 대한의생명과학회지
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    • 제10권4호
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    • pp.435-445
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    • 2004
  • The characteristics of the testis and the annual cycle of the seminiferous epithelium of the Miniopterus schreibersi fuliginosus were examined by optical microscopy. The testis weight and diameter of the seminiferous tubules were increased gradually from May to July, and the highest activity was observed in August. The size then decreased rapidly from October. Spermatogenesis began in May, peaked in August, and was suspended from October to April in the following year. Spermatocytogenesis were produced from May to July. Spermiogenesis occurred from August to September. In particular, immature spematogenic cells in the seminiferous tubules were engulfed by the phagocytosis of Sertoli cells in October. From November to April, the seminiferous tubuly contained only Sertoli cells and Ad spermatogonia. Therefore, the periodic changes in the seminiferous epithelium of M. S. fuliginosus suggest that a long hibernation is an adaptive strategy for the preservation of energy and the regulation of the breeding cycle.

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A Study on Learners' Perceptions and Learning styles of Task Research (R&E) conducted by Science High School Students

  • Dong-Seon Shin;Jong Keun Park
    • International Journal of Advanced Culture Technology
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    • 제11권4호
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    • pp.286-294
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    • 2023
  • We studied learners' perceptions and learning styles of project research activities in the chemical field conducted by 54 science high school students. In a survey of students' perceptions of task research, positive responses were found in "internal motivation," "cooperation," "task solving," and "tenacity and immersion," and statistically significant differences were found in "self-directedness," "cooperation," and "tenacity and immersion" by year. The 'lower' group responded most positively in the 'cooperation' category, and the 'higher' group responded most positively in the 'task solving' category. As a result of investigating the learning styles of the students who conducted the task research, it was found in the order of assimilator, converger, accommodator, and diverger. The assimilators showed the characteristic of systematically and scientifically approaching the problem. Convergers were found to have excellent problem-solving and decision-making ability, are practical, and have experimental-based thinking characteristics. In this study, the characteristics of science high school students showed well in the results of the learning style performed.

한국응용곤충학회의 첫 50년 역사 (History of the Korean Society of Applied Entomology for its First Fifty Years)

  • 부경생
    • 한국응용곤충학회지
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    • 제51권2호
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    • pp.171-190
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    • 2012
  • The Korean Society of Applied Entomology (KSAE) celebrates its First 50 years history this year, 2011. It began in the year 1962, as the Korean Society of Plant Protection (KSPP) to discuss all aspects of plant protection including entomology and plant pathology. At that time it was one of the earliest scientific ones among agricultural societies in Korea. Before liberation from the Japanese colonial rule there were a few scientific societies for Japanese scientists only in the Korean Peninsula. It seemed that there was a single exception, in medical field, formed by and operated for Korean ethnics. Right after the liberation, Korean scientists rushed to form new scientific societies in the fields of mechanical engineering, architecture, textile, internal medicine, biology, etc. in 1945, mathematics, chemistry, metallurgy, etc. in 1946, and so on. But agricultural scientists had to wait for more time before setting up their own scientific society, Korean Agricultural Society(韓國農學會), comprising all agricultural subfields, in 1954. They had annual meetings and published their own journal every year until 1962. Then those working in the plant protection field established their own KSPP, right after their section meeting in 1962. At that time the total number of participants for KSPP were only around 50. KSPP scientists were interested in plant pathology, agricultural chemicals, weed science, or bioclimate, besides entomology. They had annual meetings once or twice a year until 1987 and published their own journal, Korean Journal of Plant Protection (KJPP), once a year at the earlier years but soon gradually increasing the frequency to four times a year later. Articles on entomology and plant pathology occupied about 40% each, but the number of oral or posters were a little bit higher on plant pathology than entomology, with the rest on nematology, agricultural chemicals, or soil microarthropods. There also had a number of symposia and special lectures. The presidentship lasted for two years and most of president served only one term, except for the first two. The current president should be $28^{th}$. In the year 1988, KSPP had to be transformed into the applied entomology society, Korean Society of Applied Entomology (KSAE), because most of plant pathologists participating left the society to set up their own one, Korean Society of Plant Pathology in 1984. Since that time the Society concentrates on entomology, basic and applied, with some notes on nematology, acarology, soil microarthropods, agricultural chemicals, etc. The Society has been hosting annual meetings at least twice a year with special lectures and symposia, from time to time, on various topics. It also hosted international symposia including binational scientific meetings twice with two different Japanese (applied entomology in 2003 and acarology in 2009) societies and the Asia-Pacific Congress of Entomology in 2005. The regular society meeting of this year, 2011, turns out to be the 43rd and this autumn non-regular meeting would be the 42nd. It has been publishing two different scientific journals, Korean Journal of Applied Entomology (KJAE) since 1988 and the Journal of Asia-Pacific Entomology (JAPE) since 1998. Both journals are published 4 times a year, with articles written in Korean or English in the first, but those in English only in the latter with cooperation from the Taiwan Entomological Society and the Malaysian Plant Protection Society since 2008. It is now enlisted as one of those SCI(science citation index) extended. The highest number of topics discussed at their annual meetings was on ecology, behavior, and host resistance. But at the annual meetings jointly with the Korean Society of Entomology, members were more interested in basic aspects, instead of applied aspects, such as physiology and molecular biology fields. Among those societies related to entomology and plant protection, plant pathology, pesticide, and applied entomology societies are almost similar in membership, but entomology and plant pathology societies are publishing more number of articles than any others. The Society is running beautifully, but there are a few points to be made for further improvement. First, the articles or posters should be correctly categorized on the journals or proceedings. It may be a good idea to ask members to give their own version of correct category for their submissions, either oral or poster or written publication. The category should be classified detailed as much as possible (one kind of example would be systematics, morphology, evolution, ecology, behavior, host preference or resistance, physiology, anatomy, chemical ecology, molecular biology, pathology, chemical control, insecticides, insecticide resistance, biocontrol, biorational control, natural enemies, agricultural pest, forest pest, medical pest, etc.) and such scheme should be given to members beforehand. The members should give one or two, first and second, choices when submitting, if they want. Then the categories might be combined or grouped during editing for optimal arrangement for journals or proceedings. Secondly the journals should carry complete content of the particular year and author index at the last issue of that year. I would also like to have other information, such as awards and awardees in handy way. I could not find any document for listing awards. Such information or article categorization may be assigned to one of the vice presidents. I would rather strongly recommend that the society should give more time and energy on archive management to keep better and more correct history records.

Preliminary study for aging of latent fingerprints on nonporous substrate

  • Nam Yee Kim;Woo-Yong ParK;Jong Shin Park;Yuna Kim;Hee Sook Kim
    • 분석과학
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    • 제36권2호
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    • pp.80-88
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    • 2023
  • Fingerprints play a crucial role in the identification of potential suspects in criminal cases. However, determining the actual time, i.e., the time at which the fingermark was deposited, is challenging. Herein, we investigated the persistence and aging of fingerprints over time by observing the time evolution of latent fingerprints on a polystyrene box stored in a dark room. Fingerprint samples that were stored for up to two years could be detected with maximum accuracy using a black iron-oxide-based emulsion (black emulsion). To estimate the time of fingerprint deposition, fingerprint aging was studied by analyzing the lipid components of the fingerprints after their development. Cholesterol and squalene were selected as indicators of fingerprint aging, and their ratio was estimated to assess aging. In the case of fingerprint samples stored in a dark room for up to one month after deposition, the cholesterol/squalene ratio was approximately 0.01; it increased gradually to ≥ 0.1 over six months. A substantial reduction in the levels of cholesterol and squalene from the initial levels was also noted. Cholesterol and squalene were not detected after one year of storage. Thus, the extent of aging could be determined by analyzing the aging indicators for up to six months. Two cases that could cause error in the estimation of the fingerprint deposition time, namely, heating of the fingerprint sample before development and storage of the developed fingerprints in a dark room, were also investigated.