• Journal of Conservation Science
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• v.37 no.2
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• pp.154-166
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• 2021

The royal seal, in either gold or jade, is used to symbolize Joseon's royal family, and it is made up of a Bonu (a handle), Bosin (a body), Bomun (a letter inscribed on the seal), and Bosu (a string attached to the seal). The Bosu was designed to enhance the seal's dignity and facilitate convenient handling. Bosu consists of Kkeun-mog and Bangwool-sul (decorated with gilt paper), which are made of Bangwool, Bangwool-mog, and Sul. In this study, the form survey, color, material, and composition of 318 Bosu pieces from the Joseon Dynasty and Korean Empire produced from 1441 to 1928 were analyzed. As time passed, the strings on the seals became longer and thinner. Bangwool-mog disappeared from the mid-1800s, and a ring appeared at the end of the Sul. Most of the colors used were scarlet, but orange and purple were also identified. Although most of the Bosu are silk, five Bosu from the 1900s and one Bosu from the 1740s (likely replaced in the 1900s) are estimated to be rayon. The gilt paper's main chemical components used to decorate the Bangwool-sul vary according to age. Until the mid-1800s, gold (Au) was used for the Sul and Bangwool, but since the mid-1800s, gold (Au) and brass (Cu-Zn) were used for Sul and Bangwool, respectively, and then brass (Cu-Zn) was used for Sul and Bangwool. While the Bosu was a seal accessory, it can be used to identify changes in the manufacturing techniques and materials of the period.

• Clean Technology
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• v.27 no.2
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• pp.160-167
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• 2021

This study investigated the environmental effects of improving the general-type activated carbon adsorption tower used at the Sihwa/Banwol Industrial Complex with use of a cartridge-type activated carbon adsorption tower for the application of an activated carbon co-regenerated system. Four general-type activated carbon adsorption towers and two cartridge-type activated carbon adsorption towers were selected to analyze the properties of activated carbon and to compare the efficiency of reducing environmental pollutants. The results showed that the activated carbon used in the cartridge-type activated carbon adsorption towers was high quality activated carbon with an iodine adsorption force of more than 800 mg/g and that a good adsorption performance was maintained within the replacement cycle. From an analysis of the environmental pollutant reduction efficiency, it was confirmed that the cartridge-type activated carbon adsorption tower functioned properly as a prevention facility for handling emissions pollutants with a treatment efficiency of total hydrocarbons (THC), toluene, and methylethylketone (MEK) components of 71%, 77%, and 80%, respectively. The general activated carbon adsorption tower, which was confirmed to use low-performance activated carbon, had a very low treatment efficiency and did not function properly as a prevention facility for dealing with emission pollutants. It is believed that it is possible to reduce pollutants during operations by changing from the general-type activated carbon adsorption tower to a cartridge-type activated carbon adsorption tower.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.1
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• pp.1-10
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• 2021

Radiopharmaceuticals are drugs that contain radioisotopes and are used in the diagnosis, treatment, or investigation of diseases. Radiopharmaceuticals must be manufactured in compliance with good manufacturing practice regulations and subjected to quality control before they are administered to patients to ensure the safety of the drug. Radiopharmaceuticals for administration to humans need to be sterile and pyrogen-free. Hence, sterility tests and membrane filter integrity tests are carried out to confirm the asepticity of the finished drug product, and a bacterial endotoxin test conducted to assess contamination, if any, by pyrogens. The physical appearance and the absence of foreign insoluble substances should be confirmed by a visual inspection. The chemical purity, residual solvents, and pH should be evaluated because residual by-products and impurities in the finished product can be harmful to patients. The half-life, radiochemical purity, radionuclidic purity, and strength need to be assessed by analyzing the radiation emitted from radiopharmaceuticals to verify that the radioisotope contents are properly labeled on pharmaceuticals. Radiopharmaceuticals always carry the risk of radiation exposure. Therefore, the time taken for quality control tests should be minimized and care should be taken to prevent radiation exposure during handling. This review discusses the quality control procedures and acceptance criteria for a diagnostic radiopharmaceutical.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.1
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• pp.1-7
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• 2023

Chlorine dioxide (ClO₂) is widely used for post-harvest sterilization treatment. However, there are limitations in the retail application of ClO₂ due to difficulties in handling, expensive facilities, and safety concerns. Therefore, it is necessary to develop a ClO₂ technology that can be easily applied and continuously released for a long period. In this study, a series of ClO₂ self-releasing sachets were developed. First, poly(ether-block-amide) (PEBAX) and polyethylene-glycol (PEG) composite films containing different ratios of citric acid (CA) were prepared using the solution casting method. The as-prepared PEBAX/PEG-CA composite films were evaluated using FT-IR, DSC, and TGA to confirm chemical structure and thermal properties. Subsequently, PEBAX/PEG-CA composite films were designed in the form of a sachet and NaClO₂ powder was transferred into the sachet to achieve a ClO₂ self-releasing system. The ClO₂-releasing behavior of the sachet was investigated by measuring the release amount of the gas using UV-vis. The release amount of ClO₂ increased with increasing CA contents owing to the existence of higher protons (trigger) in the polymer matrix. Further, ClO₂ gas was released for a longer time. Therefore, the as-prepared smart sachet can be tuned according to applications and packaging sizes to serve an optimal sterilization effect.

• Resources Recycling
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• v.32 no.3
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• pp.3-8
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• 2023

This study discussed production, demand, and future prospects of rubidium, which is an alkali group metal that is highly reactive to various media and requires carefulness in handling, but no significant environmental hazard of rubidium has been reported yet. Rubidium is used in various fields such as optoelectronic equipment, biomedical, and chemical industries. Because of difficulty in production as well as limited demand, the transaction price of rubidium is relatively high, but its detail information such as market status and potential growth is uncertain. However, if the mass production of versatile ultra-high-performance equipment such as quantum computers and the necessity of rubidium use in the equipment are confirmed, there is a possibility that the rubidium market will expand in the future. Rubidium is often found together with lithium, beryllium, and cesium, and may be present in granite containing minerals such as lepidolite and pollucite, as well as in seawater and industrial waste. Several technologies such as acid leaching, roasting, solvent extraction, and adsorption are used to recover rubidium. The maximum recovery efficiency of the rubidium from the sources and the processing above is generally high, but, in many practices, rubidium is not the main recovery target, and therefore the actual recovery effects should depend on presence of other valuable components or impurities, together with recovery costs, energy consumption, environmental issues, etc. In conclusion, although the current production and consumption of rubidium are limited, with consideration of the possible market fluctuations according to the emergence of large-scale demand sources, etc., further investigations by related institutions should be necessary.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.4
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• pp.403-411
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• 2023

Objectives: Formalin is used as an anthelmintic in farms where flounder are raised. In this study, we aim to identify formaldehyde exposure levels for aquaculture industry workers and provide basic data for managing formaldehyde exposure. Methods: Exposure levels of formaldehyde in the air, including formalin spraying operations, were assessed separately for personal and area samples. In addition, considering the formalin administration method, dermal exposure to the hands was estimated when administering the chemical, and dermal exposure to the legs during water tank work was estimated by collecting water in the water tank and evaluating the amount of formaldehyde remaining. Finally, the respiratory exposure level and the estimated dermal exposure level were added to derive the total exposure level and compared with the maximum allowable human dose. Results: As a result of the airborne evaluation, the formaldehyde concentration of the worker (1 person) who performed the formalin spraying and flounder sorting was 33.61 ppb, and the arithmetic mean of formaldehyde concentrations of the workers (3 people) who only performed the flounder sorting was 3.28 ppb (range: 2.25-4.89 ppb). In the case of dermal exposure, when spraying formalin once, the amount was estimated to be 0.33-2.62 mg when wearing protective gear and 3.27-26.12 mg when not wearing it. Conclusions: There was a difference in the formaldehyde exposure level of workers depending on their operation of handling formalin and whether or not protective gear was worn. In particular, because the level of formaldehyde exposure due to dermal exposure can be significant, there is a need to improve formalin administration methods in a way that avoids skin contact as much as possible.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.43-49
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• 2023

Hydrofluoric acid is a less acidic substance than hydrochloric acid, nitric acid, and sulfuric acid, but it is one of the most dangerous substances for humans. In recent years, it has become an indispensable substance in industries such as chemical plants and the semiconductor industry, and although it is a threat to the human body, its use is increasing for various purposes, and the amount of use is constantly increasing due to the expansion and development of the industry. The dangers of hydrogen fluoride have been highlighted since the 2012 accident, which led to a more than fivefold increase in management standards for handling facilities. Hydrogen fluoride converts to hydrofluoric acid when exposed to the air, which can be fatal to humans. This study simulates the effects of a release of a toxic substance in the workplace, even though a protection layer has been provided to minimize the damage caused by the released toxic substance, and recommend ways to control the risk to workers in the event of a release in the workplace.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.529-540
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• 2011

The purpose of this study was to analyze experiments for the rules of material change unit in 9th grade science textbooks and develop experiments applying small-scale chemistry (SSC). For this study, experimental methods for the precipitation experiment, water electrolysis experiment, decomposition of hydrogen peroxide experiment presented in the 9 science textbooks were analyzed. Problems and improvements that were needed were extracted by 13 science teachers performing the experiments. Experiments applying SSC were developed based on the improvements needed. Afterwards, 19 pre-service science teachers performed both the developed SSC experiments and the science textbooks' experiments. A questionnaire about merits and demerits of the experiments applying SSC was performed. According to the results of this study, most of the 9th grade science textbooks included the lead iodide precipitation experiment, water electrolysis experiment by Hoffman voltameter, and decomposition of hydrogen peroxide experiment using catalytic manganese dioxide. Improvements were needed on the quantity of reagents, time for performing experiments, and scale of experimental apparatus. Merits of the developed experiments applying SSC which used small amount of reagents were safety, easy waste material disposal, short reaction time, and reproducible experimental results. Demerits of the experiments applying SSC were difficulty in observing, decreased achievement, and lack of skill in handling small-scale apparatus. Therefore, if the experiments developed applying SSC were to be utilized in 9th grade science experiments, it will be possible to use less reagent and be able to teach and carry out reproducible experiments at the same time. Also, the reproducible experiments based on SSC will help students under stand the scientific concepts for the rules of material change unit.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.268-277
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• 2013

This study investigates the effects of accumulated levels of heavy metals and nutrients of cultivated soybean plant tissues, after the continuous application of sewage sludge (SS) and industrial sludge (IS). SS and IS were applied to soybean plants at loading of 0, 11.25, 22.50, and 45.00 Mg/ha, and the contents of heavy metals (Cd, Pb, Ni, Cu, and Zn), proteins, and amino acids in the cultivated soybean plants were measured. The Cd content in the soybean was 0.02~0.05 mg/kg, which is within the safety level set in the standard, and that of Pb was 0.02~0.15 mg/kg, which is also within the safety level except for IS 45 Mg/ha. The soybean harvest quantity was higher in the treatment groups than the control group in the first year. However, in the second year, SS had lower harvest and IS had the same level or a decreasing tendency, compared with the control group. In the first year, the content of amino acid which followed handling of SS was increased in the sludge groups more than in the control group in the case of glutamate. However, the influence of continuous application was increased in the sludge groups in the case of amino acids of 12 types. In conclusions, the accumulation in soybean of heavy metals by sludge treatment is not a problem, but the decreased yields needs to be considered. In addition, the most appropriate level of sludge treatment was 11.25 Mg/ha.

• Journal of Life Science
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• v.17 no.4 s.84
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• pp.498-502
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• 2007

A total of 5 female elk deer($220kg{\pm}10kg$) were included in a study on the changes in physico-chemical properties of deer meat during storage at $-4^{\circ}C\;and\;-2^{\circ}C$. The deers were exposed to normal pre-slaughter handling and put under anesthesia before slaughtered. The loin and leg cuts were deboned from the carcass after 24hrs slaughter. The samples weighing approximately 300g were packaged using wrap packaging and stored for 1, 2, 3, 4, 5 and 6 months at $-30^{\circ}C\;and\;-60^{\circ}C$. During the freezing period, the changes of moisture maintenance was slower for the meats kept at $-60^{\circ}C$ than that at $-30^{\circ}C$. The meat softness represented higher value after freezing, and it tended to be decreased with the passage of storage time. Comparing the values between freezing temperature, the value at $-30^{\circ}C$ was higher than at $-60^{\circ}C$. All meats frozen at $-30^{\circ}C\;and\;-60^{\circ}C$ were edible after storage for 6 months. Loin was inedible, and leg was edible after freezing storage for 6 months. The pH values of the meats were increased during freezing period, even though pH value of the meats stored for 6 months was less than 5.70. Luminosity of loin was significantly increased with the passage of storage time, although loin stored at $-60^{\circ}C$ was darker, and leg stored at $-30^{\circ}C$ was darker. The index of red color was rapidly decreased for loin stored at $-30^{\circ}C$, and for leg stored at $-60^{\circ}C$, respectively. There were no changes in the index of yellow color for loin stored at $-60^{\circ}C$, and the index for leg was increased with regardless of the freezing storage temperature after 6 months.