• Proceedings of the Korean Vacuum Society Conference
• /
• 한국진공학회 1998년도 제14회 학술발표회 논문개요집
• /
• pp.17-17
• /
• 1998

Synchrotron radiation is produced when charged particles moving with relativistic velocities a are accelerated - for example, deflected by the bending magnets which guide the electron or p positrons in circular accelerators or storage rings. By using special focusing magnetic lattices i in the particle accelerators it is possible to make the dimensions of the particle beam very small with a hi맹 charge density which results in a light source with high b디lIiance. Synchrotron light h has important properties which make it ideal for a wide range of investigations in surface s science. The fact that the spectrum of electromagnetic radiation emitted in a bending magnet e extends in a continuum from the 얹r infra red region to hard x-rays means that it is id않I for a v variety of spectroscopic studies. Since there are no convenient lasers, or other really bright l light sources, in the vacuum ultraviolet and soft x-ray re.밍ons the development of synchrotron r radiation has enabled enormous advances to be made in this di펌C비t spectr따 re밍on. P Polarization-dependent measurements, for ex없nple ellipsometry or circular dichroism studies a are possible because the radiation has a well-defined polarization - linear in the plane of orbit w with additional right-circular, or left-circular, components for emission an생es above, or below, t the horizontal, respectively. Since the synchrotron light is emitted from a bunch of charge c circulating in a ring the light is emitted with a well-defined time structure with a short flash of l light every time a bunch passes an exit port. The time structure depends on the size of the ring a and the number and sequence of filling of the bunches. A pulsed light source enables time¬r resolved studies to be performed which provide direct information on the lifetimes and decay m modes of excited states and in addition opens up the possibility of using time of flight t techniques for spectroscopic studies. The fact that synchrotron radiation is produced in a clean u ultrahi야 vacuum environment is of gr않t importance for surce science studies. The current t비rd generation synchrotron light sources provide exceptionally high baliance and stability a and open up possibilities for experiments which would have been inconceivable only a short time ago.

• Plant Journal
• /
• 제18권4호
• /
• pp.66-72
• /
• 2023

In order to respond to the demand for flexible operation of thermal power generation, development of natural sliding pressure operation that minimizes throttle loss by opening the turbine control valve 100% and maximize power generation efficiency in conjunction with ESS in order to quickly respond to fluctuations in the system frequency is required. The logic development of natural sliding pressure operation with ESS was developed to modify the existing logic at the power plant's top-level control logic such as the unit master, the boiler master and the turbine master. Cooperative control algorithms that complement the advantages and disadvantages of ESS operation (quick response, limited capacity) and power plant operation (slow response, continuous operation) not only improve efficiency when applied to actual power plants, but also respond quickly and flexibly to load demands to ensure system stability.

• Nuclear Engineering and Technology
• /
• 제55권4호
• /
• pp.1439-1447
• /
• 2023

The fuel cycle characteristics of the IVG.1M reactor were studied within the framework of the research reactor conversion program to modernize the IVG.1M reactor. Optimum use of the nuclear fuel and reactor was achieved through routine methods which included partial fuel reloading combined with scheduled maintenance operations. Since, the additional problem in planning the fuel cycle of the IVG.1M reactor was the poisoning of the beryllium parts of the core, reflector, and control system. An assessment of the residual power and composition of spent fuel is necessary for the selection and justification of the technology for its subsequent management. Computational studies were performed using the MCNP6.1 program and the neutronics model of the IVG.1M reactor. The proposed scheme of annual partial fuel reloading allows for maintaining a high reactor reactivity margin, stabilizing it within 2-4 β_eff for 20 years, and achieving a burnup of 9.9-10.8 MW × day/kg U in the steady state mode of fuel reloading. Spent fuel immediately after unloading from the reactor can be placed in a transport packaging cask for shipping or safely stored in dry storage at the research reactor site.

• Journal of Microbiology and Biotechnology
• /
• 제33권10호
• /
• pp.1337-1350
• /
• 2023

Caproic acid is a precursor substance for the synthesis of ethyl caproate, the main flavor substance of nongxiangxing baijiu liquor. In this study, Clostridium butyricum GD1-1, a strain with high caproic acid concentration (3.86 g/l), was isolated from the storage pit mud of nongxiangxing baijiu for sequencing and analysis. The strain's genome was 3,840,048 bp in length with 4,050 open reading frames. In addition, virulence factor annotation analysis showed C. butyricum GD1-1 to be safe at the genetic level. However, the annotation results using the Kyoto Encyclopedia of Genes and Genomes Automatic Annotation Server predicted a deficiency in the strain's synthesis of alanine, methionine, and biotin. These results were confirmed by essential nutrient factor validation experiments. Furthermore, the optimized medium conditions for caproic acid concentration by strain GD1-1 were (g/l): glucose 30, NaCl 5, yeast extract 10, peptone 10, beef paste 10, sodium acetate 11, L-cysteine 0.6, biotin 0.004, starch 2, and 2.0% ethanol. The optimized fermentation conditions for caproic acid production by C. butyricum GD1-1 on a single-factor basis were: 5% inoculum volume, 35℃, pH 7, and 90% loading volume. Under optimal conditions, the caproic acid concentration of strain GD1-1 reached 5.42 g/l, which was 1.40 times higher than the initial concentration. C. butyricum GD1-1 could be further used in caproic acid production, NXXB pit mud strengthening and maintenance, and artificial pit mud preparation.

• International Journal of Computer Science & Network Security
• /
• 제24권3호
• /
• pp.23-28
• /
• 2024

The multi-tenancy and high scalability of the cloud have inspired businesses and organizations across various sectors to adopt and deploy cloud computing. Cloud computing provides cost-effective, reliable, and convenient access to pooled resources, including storage, servers, and networking. Cloud service models, SaaS, PaaS, and IaaS, enable organizations, developers, and end users to access resources, develop and deploy applications, and provide access to pooled computing infrastructure. Despite the benefits, cloud service models are vulnerable to multiple security and privacy attacks and threats. The SaaS layer is on top of the PaaS, and the IaaS is the bottom layer of the model. The software is hosted by a platform offered as a service through an infrastructure provided by a cloud computing provider. The Hypertext Transfer Protocol (HTTP) delivers cloud-based apps through a web browser. The stateless nature of HTTP facilitates session hijacking and related attacks. The Open Web Applications Security Project identifies web apps' most critical security risks as SQL injections, cross-site scripting, sensitive data leakage, lack of functional access control, and broken authentication. The systematic literature review reveals that data security, application-level security, and authentication are the primary security threats in the SaaS model. The recommended solutions to enhance security in SaaS include Elliptic-curve cryptography and Identity-based encryption. Integration and security challenges in PaaS and IaaS can be effectively addressed using well-defined APIs, implementing Service Level Agreements (SLAs), and standard syntax for cloud provisioning.

• Nuclear Engineering and Technology
• /
• 제56권3호
• /
• pp.993-1001
• /
• 2024

The TANDEM project is a European initiative funded under the EURATOM program. The project started on September 2022 and has a duration of 36 months. TANDEM stands for Small Modular ReacTor for a European sAfe aNd Decarbonized Energy Mix. Small Modular Reactors (SMRs) can be hybridized with other energy sources, storage systems and energy conversion applications to provide electricity, heat and hydrogen. Hybrid energy systems have the potential to strongly contribute to the energy decarbonization targeting carbon-neutrality in Europe by 2050. However, the integration of nuclear reactors, particularly SMRs, in hybrid energy systems, is a new R&D topic to be investigated. In this context, the TANDEM project aims to develop assessments and tools to facilitate the safe and efficient integration of SMRs into low-carbon hybrid energy systems. An open-source "TANDEM" model library of hybrid system components will be developed in Modelica language which, by coupling, will extend the capabilities of existing tools implemented in the project. The project proposes to specifically address the safety issues of SMRs related to their integration into hybrid energy systems, involving specific interactions between SMRs and the rest of the hybrid systems; new initiating events may have to be considered in the safety approach. TANDEM will study two hybrid systems covering the main trends of the European energy policy and market evolution at 2035's horizon: a district heating network and power supply in a large urban area, and an energy hub serving energy conversion systems, including hydrogen production; the energy hub is inspired from a harbor-like infrastructure. TANDEM will provide assessments on SMR safety, hybrid system operationality and techno-economics. Societal considerations will also be encased by analyzing European citizen engagement in SMR technology safety.

• Food Science and Preservation
• /
• 제16권6호
• /
• pp.810-816
• /
• 2009

To identify effective food packaging compounds that could significantly affect the freshness of stored food, the efficiency and performance of porous polypropylene film containing mustard oil as a freshness maintenance ingredient was studied by GC-MS analysis and storage testing of bread. AITC (allyl-isothiocyanate)-emitting properties of films impregnated with mustard oil were evaluated by GC-MS. AITC was extracted from mustard oil, and used as a vapor as an effective antimicrobial agent. Films were prepared under four different conditions (the film types were abbreviated 25SF1, 25SF2, 50LF, and IAF) and the amounts of AITC inside vinyl packs constructed using the four films were measured. The results showed that the 25SF2 film (width 25 mm, length 20 cm) yielded a greater amount of AITC than did the 50LF film (width 50 mm, length 20 cm). We confirmed that the amount of gas emission showed better between layer and layer of the film side than the internal film. In storage testing using various films at $35^{\circ}C$ for 25 days, 25SF2 film provided excellent preservation of bread compared with 50LF film. This was in line with the fact that 25SF2 film yielded the highest amount of AITC. Emission capacities AITC of 2 cm film were measured using bottles various volumes (43 mL, 500 mL, 1000 mL) and both closed and open systems. The AITC content of the film in 43 mL bottle was much higher than that yielded by other films in the closed system, and AITC was rapidly emitted, with relatively low residual gas emission after 4 days in an open system. Mustard oil is a useful freshness maintenance ingredient hence, analysis of AITC emission kinetics from various films were helpful to develop films with optimal antimicrobial effects, and will allow application of such films in food packaging systems.

• Economic and Environmental Geology
• /
• 제44권1호
• /
• pp.37-48
• /
• 2011

Some industrial minerals used in domestic industries such as monazite, apatite, bauxite, and ilmenite belong to NORM (Naturally Occurring Radioactive Materials) because they show a high radioactivity. Products, semi-products, wastes, and by-products which show higher radioactivity than NORM belong to TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials). Apatite used for manufacturing phosphate fertilizer in Namhae Chemical company belongs to NORM, and its by-product, phospo-gypsum, belongs to TENORM. A geological investigation is needed for the future environmental impact assessment of the Namhae Chemical company's site. According to survey results of the Namhae Chemical company's site, soil mineral composition indicated the mixture of minerals derived from the country rock (quartz, feldspar, mica, $l4{\AA}$ mineral, kaolin and amphibole) and minerals from the gypsum open-air storage yard (gypsum and apatite). Soil samples showed average content of U 4.6 ppm and Th 10 ppm, which are similar to average crustal abundances. They also show average contents of $^{40}K$ 191-1,166 Bq/kg, $^{226}Ra$ 15.6-710 Bq/kg, and $^{232}Th$ 17.4-72.7 Bq/kg, which indicate moderate levels of radio nuclide. But $^{226}Ra$ anomaly in the gypsum open storage yard is clearly confirmed and $^{232}Th$ anomaly is also confirmed in the east road side of the factory and nearby mountain areas. Soil external hazard indices ranged 0.24-2.01 with the average 0.54. Although most external hazard indices were lower than 1, which means radiation hazard index to be negligible, 5 samples out of total 40 samples showed higher values than 1, and further detailed investigation is needed.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• 제8권2호
• /
• pp.90-100
• /
• 1975

The estimation of the pre-processing condition of oyster is of great importance for distributors and processors. This study was attempted to establish the basic data for evaluating the processing suitability of oyster, which is the most important shellfish for domestic use and export. The data were analysed by measuring the condition index, chemical composition and heavy metal content of oysters. In order to eliminate the manual work that has to be done on a tightly closed oyster shell and avoid shrinkage in the oyster meat which is attendant on the steaming process, chemical means to open oyster were examined. finding the method of pretreatment of polyphosphate for frozen oysters were attempted to improve the product quality. The prevention of undesirable color change of the canned oyster meat is another problem to solve. The important results are as follows : 1. The ratio of meat volume and meat weight to the holding capacity by shells may be useful as an index to measure the condition index of oysters. 2. As a whole, monthly changes of moisture and fat content in oysters were reversely correlated. Protein content slightly decreased from April and rapidly decreased in July, and again rapidly increased in August but from September to November decreased slightly. In April, the content of glycogen was 4 percent. From this period to September, glycogen was rapidly decreased. From July to September, it was only 0. 7 to 1 percent but increased from October. There were little seasonal changes in pH value. The pH value of oyster meat was 6.0 to 6.2. The crude ash content was slightly decreased from June to August. 3. The range of monthly change of heavy metal content are as follows: Total mercury was 0 to 0.019 ppm, cadmium was 0.026 to 0.053 ppm, copper was 0.111 to 0.594 ppm, and lead_was 0.061 to 0.581 ppm. 4. By the results of condition index, chemical composition and heavy metal content of oysters, the suitable harvest season as raw materials for processing was the end of December to the end of May of next year. 5. The pretreatment of 10 percent polyphosphate in 5 percent salt solution of oyster meat appeared effective to reduce thawing drip during cold storage. 6. The pretreatment of $Na_2EDTA$ and BHA did not show the color prevention effect to the canned oyster meat during storage. 7. Magnesium chloride affected to open the valves of oysters.

• Journal of Life Science
• /
• 제20권8호
• /
• pp.1193-1200
• /
• 2010

The cDNA cloning and developmental profiles of the mRNA for A. pernyi arylphorin was determined. The complete A. pernyi arylphorin cDNA sequence comprised 2,234 bp (without the poly $A^+$ tail), including an open reading frame of 2,112 bp beginning with a methionine ATG at bp34. The A. pernyi arylphorin contained 704 amino acids which are highly enriched in aromatic amino acids, phenylalanine and tyrosine. The calculated molecular mass of the A. pernyi arylphorin from the ORF was 83,439 Da. The deduced amino acid sequence of A. pernyi arylphorin showed 78, 71, 62 and 64% identity with those of H. cecropia, M. sexta $\alpha$ subunit, M. sexta $\beta$ subunit and B. mori storage protein. In Northern blot analysis, the A. pernyi arylphorin mRNA only in the fat body of the 5th instar larvae was responsible for gene expression of the protein, and the synthetic activity of the mRNA was detected strongly in the early larvae, but not in the middle or late-stage larvae. In addition, a very weak signal in mRNA activity was detected in pupal stages, but this was considered to be inactive mRNA after reviewing the results of the labeling experiment of this protein.