• Mass Spectrometry Letters
• /
• v.11 no.4
• /
• pp.108-112
• /
• 2020

A certified reference material (CRM) for the analysis of nutrient elements in an edible mushroom (Ganoderma lyceum) powder has been developed (KRISS CRM 108-10-011). The mass fractions of calcium (Ca), iron (Fe), and zinc (Zn) were measured by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). To dissolve the fungi cell wall of mushroom consisted of chitin fibers, sample preparation method by single reaction chamber type microwave-assisted acid digestion with acid mixtures was optimized. The mean measurement results obtained from 12 sample bottles were used to assign as the certified values for the CRM and the between-bottle homogeneities were evaluated from the relative standard deviations. The certified values were metrologically traceable to the definition of the kilogram in the International System of Units (SI). This CRM is expected to be used for validation of analytical methods or quality control of measurement results in analytical laboratories when they determine the mass fractions of elements in mushroom or other similar samples.

• Analytical Science and Technology
• /
• v.37 no.1
• /
• pp.1-11
• /
• 2024

In agricultural households cultivating vegetables and fruits, the use of various pesticides to protect crops from diseases and pests or to control weeds is widely practiced enhancing quality and productivity. However, pesticides can pose a threat to consumer health by remaining on the food surface or migrating into the food interior. Households commonly peel off skins, wash with water, or use chemical methods to remove foreign substances including residual pesticides on the food surface. In this study, we measured the washing rate by comparing the pesticide concentrations before and after washing in the leafy vegetable perilla leaves and the fruits strawberries and apples, which were intentionally exposed to pesticides. We compared washing rates using tap water, a baking soda solution, and a commercially available food-specific cleaning solution. The target pesticides for analysis were azoxystrobin, bifenthrin, boscalid, difenoconazole, flubendiamide, and indoxacarb, and the residual pesticide analysis was performed using GC-MS/MS or LC-MS/MS. The removal rates of pesticides were highest with the food-specific cleaner, followed by baking soda and tap water in order.

• Journal of Ginseng Research
• /
• v.15 no.3
• /
• pp.224-230
• /
• 1991

The seven traditional quality factors including age and root weight ect. were reviewed in relation to the chemical components as a new quality factor and pharmacological data. The other important factor, production place, appeared to be sum of the eight factors. The important of production place indicated that the best quality ginseng is produced in the optimum environment. The description of ginseng for medicinal use in present materia medica missed most traditional quality factors only indicating the change by processing. Such phenomena do not mean the significant of raw$.$ ginseng quality. since appropriate raw ginseng was supplied in traditional way. For the generation with analytical attitude the description of raw ginseng quality to the processed ginseng products is recommendable. For the quality control with biologically active or index compound, the composition of various compounds seems to be the best. The establishment of physical and chemical quality creteria that will match with the traditional mothod it needed and will accomplished by comparative research on raw ginseng from various production sites and growth conditions. The description of production-place, grade and quantity of raw ginseng to the processed products will give better information and higher popularity of products to consumers.

• Analytical Science and Technology
• /
• v.13 no.5
• /
• pp.675-682
• /
• 2000

The concentration of dioxins from flue gases of municipal waste incineration facilities with capacities over 50 tons/day are regulated by the guideline: $0.1ng-TEQ/Nm^3$ for new facilities, and $0.5ng-TEQ/Nm^3$ for existing facilities and it will be strengthened to $0.1ng-TEQ/Nm^3$ until 2003 year. Dioxins from these incineration facilities have to be measured more than 2 times annually by the Official Test Facilities of Dioxins. Seven institutions have been certified so far as the Official Test Facilities of Dioxins. These facilities have to be evaluated by the quality control program provided by National Institute of Environmental Research every year. We reported the results of quality control test performed in 1999. Four institutions certified in 1998 sampled flue gases at stack of M incineration facilitiy and analyzed dioxins by Official Methods of Air Pollution. The isokinetic coefficients, the parameter for evaluation of sampling ability were excellent for all four institutions. They were 100.9%, 102.4%, 102.1% and 99.2%, respectively. The criteria required are as follows; resolution over 10,000, mass calibration within ${\pm}5ppm$, ion abundance ratio within 15%, and the recovery of 50-120%. As results, those institutions also met these parameters of Official Method of Air Pollution.

• ETRI Journal
• /
• v.28 no.1
• /
• pp.31-44
• /
• 2006

In a packet switching network, congestion is unavoidable and affects the quality of real-time traffic with such problems as delay and packet loss. Packet fair queuing (PFQ) algorithms are well-known solutions for quality-of-service (QoS) guarantee by packet scheduling. Our approach is different from previous algorithms in that it uses hardware time achieved by sampling a counter triggered by a periodic clock signal. This clock signal can be provided to all the modules of a routing system to get synchronization. In this architecture, a variant of the PFQ algorithm, called digitized delay queuing (DDQ), can be distributed on many line interface modules. We derive the delay bounds in a single processor system and in a distributed architecture. The definition of traffic contribution improves the simplicity of the mathematical models. The effect of different time between modules in a distributed architecture is the key idea for understanding the delay behavior of a routing system. The number of bins required for the DDQ algorithm is also derived to make the system configuration clear. The analytical models developed in this paper form the basis of improvement and application to a combined input and output queuing (CIOQ) router architecture for a higher speed QoS network.

• International Journal of Stem Cells
• /
• v.17 no.2
• /
• pp.130-140
• /
• 2024

Cardiac organoids have emerged as invaluable tools for assessing the impact of diverse substances on heart function. This report introduces guidelines for general requirements for manufacturing cardiac organoids and conducting cardiac organoid-based assays, encompassing protocols, analytical methodologies, and ethical considerations. In the quest to employ recently developed three-dimensional cardiac organoid models as substitutes for animal testing, it becomes imperative to establish robust criteria for evaluating organoid quality and conducting toxicity assessments. This guideline addresses this need, catering to regulatory requirements, and describes common standards for organoid quality and toxicity assessment methodologies, commensurate with current technological capabilities. While acknowledging the dynamic nature of technological progress and the potential for future comparative studies, this guideline serves as a foundational framework. It offers a comprehensive approach to standardized cardiac organoid testing, ensuring scientific rigor, reproducibility, and ethical integrity in investigations of cardiotoxicity, particularly through the utilization of human pluripotent stem cell-derived cardiac organoids.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.11a
• /
• pp.229-230
• /
• 2003

중성자 방사화분석법은 핵반응을 통해 생성시킨 방사성 동위원소로부터 방출되는 방사선을 검색하여 절대적으로 성분원소를 정량하는 핵분석기술(Nuclear Analytical Techniques)이다. 현재 한국원자력연구소의 중성자 방사화분석실에서는 대기환경분야 응용연구로서 수년 동안 대기분진을 채집하여 미량 성분원소를 정량하고 있으며, 방법의 유효화와 측정결과의 신뢰성을 확보하기 위하여 시료의 채집 및 준비, 원소분석, 측정결과의 검증 등 분석과정에 대한 품질관리를 수행하고 있다. (중략)

• Proceedings of the Membrane Society of Korea Conference
• /
• 1991.10a
• /
• pp.17-26
• /
• 1991

It can be said that the current ULSI technology has been supported and/or accomplished by a major challenge to the clean room environment and the ultrapure water equipment manufacturers as to contamination control. The required improvement in ultrapure water quality, which is shown in Figure 1, would not have been possible without significant improvements in membrane performance and enhancements in analytical capabilities.

• Journal of the Korean Applied Science and Technology
• /
• v.19 no.4
• /
• pp.302-310
• /
• 2002

Demand for organic analysis increase as industries are growing and many products are spreaded in the daily life. One of many products is oil spill dispersant. It was used for oil accident in the ocean. When oil spill dispersant spread at the ocean, the petroleum in the ocean is dispersed. The oil spill dispersant is made of non ionic surfactant and petroleum oil. The non ionic surfactant disperse petroleum from oil accident. The other part is petroleum oil which has aromatic hydrocarbon. Because the aromatic hydrocarbon is cancerogenic material, it directly injure animals in the ocean. This cause the second pollution in the human body. Many oil accidents still are controlled by oil spill dispersant. Therefore quality control of the oil spill dispersant become important and this also demand for the exact quantitative analysis of aromatic hydrocarbon. Hereupon the first we develop separate petroleum oil from surfactant. The second standardize analytical method of aromatic hydrocarbon in the separated petroleum oil.

• Journal of Power Electronics
• /
• v.17 no.4
• /
• pp.914-922
• /
• 2017

Multilevel converters have attracted a lot of attention in recent years. The efficiency parameters of a multilevel converter such as the switching losses and total harmonic distortion (THD) mainly depend on the modulation strategy used to control the converter. Among all of the modulation techniques, the selective harmonic elimination (SHE) method is particularly suitable for high-power applications due to its low switching frequency and high quality output voltage. This paper proposes a new expression for the SHE problem in five-level converters. Based on this new expression, a simple analytical method is introduced to determine the feasible modulation index intervals and to calculate the exact value of the switching angles. For each selected harmonic, this method presents three-level or five-level waveforms according to the value of the modulation index. Furthermore, a flowchart is proposed for the real-time implementation of this analytical method, which can be performed by a simple processor and without the need of any lookup table. The performance of the proposed algorithm is evaluated with several simulation and experimental results for a single phase five-level diode-clamped inverter.