• Corrosion Science and Technology
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• v.17 no.5
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• pp.225-230
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• 2018

The effects of birch sap, a possible natural corrosion inhibitor, on the corrosion behavior of steel in chloride solution were investigated. The corrosion rate was significantly reduced by the addition of 1~5 mL of birch sap to 500 mL of 3wt% NaCl or 3wt% $CaCl_2$ solution. A remarkable increase in the pitting potential in NaCl solution was observed by the addition of birch sap although it was almost constant in $CaCl_2$ solution. The corrosion rate of steel in both NaCl and $CaCl_2$ birch sap solution without addition of water was higher compared to that of aqueous solution without birch sap as the pH of the birch sap was 4.0. The presence of organic compounds like, fructose, galactose, glucose, and palmitic acid in the birch sap are thought to be adsorbed effectively on the metal surface, which provided corrosion protection. However, the inorganic elements including Na, Ca, K, Mg, Mn, S, etc. present in the birch sap exhibited no role in corrosion inhibition.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.10
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• pp.761-765
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• 2009

This research aims an optimal placement of Mobile Base Station (MBS) under HAP based network configurations with the restrictions of HAP capabilities. With clustering algorithm based on BIRCH, mobile ground nodes are clustered and the centroid of the clusters will be the location of MBS. The hierarchical structure of BIRCH enables mobile node management by CF tree and the restrictions of maximum nodes per MBS and maximum radio coverage are accomplished by splitting and merging clusters. Mobility models based on Jeju island are used for simulations and such restrictions are met with proper placement of MBS.

• Honam Mathematical Journal
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• v.30 no.1
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• pp.47-51
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• 2008

By finding two characters of subgroups of the Heisenberg group $H_{27}$ whose induced characters are same, we prove that the Birch and Swinnerton-Dyer conjectures for two elliptic curves corresponding to the characters are equivalent.

• Journal of the Korea Furniture Society
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• v.20 no.6
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• pp.560-565
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• 2009

It is known that heat treatment decreases the hygroscopicity of wood. Thus heat-treated wood is good for outdoor construction due to its improved dimensional stability. This study is to investigate the hygroscopicity and discoloration of spruce and birch boards heat-treated above $190^{\circ}C$. The equilibrium moisture contents (EMCs) at all relative humidities decreased with the increase of heat treatment temperature and/or time for both spruce and birch. It was revealed that heat-treatment temperature affected more on the hygroscopicity thaan heat-treatment time. The average basic densities decreased for the spruce specimens, but increased for the birch specimens with an increase of the treatment time and/or temperature. The same heat treatment condition (190-8) made the birch specimens darker than the spruce specimens.

• Food Science and Preservation
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• v.24 no.3
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• pp.343-350
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• 2017

Effects of high pressure processing on physicochemical and microorganisms properties in birch sap were investigated using variable high pressure processing conditions. The viable cell counts of untreated birch sap was 4.0 log CFU, whereas high pressure processed sap were not detected. In birch sap was treated with 450 to 550 MPa, microorganisms were not detected during storage period, and physicochemical properties as well as color were slightly changed. The more processing time and pressure, its quality variations were more stable and then its optimum processing condition was determined with 120 sec at 550 MPa. The microorganisms and physicochemical properties of treated birch sap were investigated during storage at $5^{\circ}C$ and $10^{\circ}C$ for 45 and 28 days. Changes of physicochemical properties of treated birch sap were smaller than those of the untreated, but viable cell count were not detected during storage period. As for pH, $^{\circ}Brix$, and turbidity result of birch sap, quality shelf life of control and treatment were 4 and 24 days, respectively. Especially, ${\Delta}E$ value of instrumental color was untreated birch sap 4 days similar with the high pressure processed it for 28 days. These results indicated that the high pressure processing can be used as an effective method to improve the shelf life of birch sap.

• Journal of the Korea Furniture Society
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• v.19 no.6
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• pp.466-474
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• 2008

We suggest layered sculpture method and color painting method with new materials for the preparation of various expressions for aesthetic model of the furniture and interior articles made of river birch. Through the analysis of the layered sculpture method and preference, we try to set a new direction for the enhancement of the decoration for the furniture or article design made of birch plywood. Also, we study the fittest manufacturing process after selecting color painting materials different from the existing painting method and goes well with the furniture or article made of river birch. Color painting which systemic application of the layered plywood from birch and new paints such as Oriental dye is one of the best schemes to realize various possibility of the furniture and wooden article made of the layered plywood, and this research result has affected positive effect on the development fields such as wooden furniture and interior articles.

• Journal of the Korean Wood Science and Technology
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• v.26 no.3
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• pp.93-99
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• 1998

Lately public interest in tree saps of maple and birch trees stimulated to increase demands for sap drink as a natural medical beverage. In order to understand factors affecting tree sap flows, birch species, particularly Betula platyphylla in Mt.Sobaek area, were monitored for daily sap flows according to factors, such as DBH, tapping hole sizes and direction of hole drilling on the trunks. The chemical constituents of saps were also analyzed. The sap flow initiated from the end of March and finished at the end of April. The flow maxima appeared from April 14th to April 26th. Total amounts of the sap flow obtained from birch tree were over 1,800 ml per day per one tree. Sap flows were increased with increasing DBH and tree age. Six milimeter drilled hole resulted in the highest sap flows. Sap flows increased with increases of diameter and height of the trees. Hole drilling to downward side(south-facing) of tree produced almost doubled sap flows than that of upward one(north-facing), while rightside drilling produced same amounts of saps to that of leftside one. Six mm drilling gave the best results not only in maximum flows but also effective hole occluding rates. The saps have in the range of 4.5 to 5.6 pH and l.0 - 2.0% of saccharinity. Sucrose, glucose, fructose and high mineral contents were found in the saps of birch tree. The tree saps could be utilized not only medicinal drink, but also one of the healthy beverages.

• Korean Journal of Heritage: History & Science
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• v.56 no.2
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• pp.206-220
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• 2023

In the royal publishing process of the Joseon Dynasty, the main species of wood used for woodblock printing was recorded as Jajak-mok. Although the name Jajak-mok may suggest Jajak-namu(white birch), it is presumed to refer to a different type of wood than Jajak-namu based on its recorded habitat and usage in historical documents. The aim of this paper is to clarify that during the Joseon Dynasty, the term Jajak-mok referred to Geojesu-namu (Korean birch), while Jajak-namu was called Hwa-mok(樺木). Additionally, this paper explores how the term Jajakmok eventually became the name of white birch, Jajak-namu, used today. In the mid-18th century, Japan used the character 樺(hwa) to refer to Beot-namu(Sargent cherry). As Japanese encyclopedias entered Joseon, the term Hwa-mok began to refer to both Beot-namu and Jajak-namu, which is also called Bot-namu. Since the pronunciation of Boet-namu and Bot-namu are similar, the two trees were eventually unified under the name Boet-namu. In the 20th century, the official names of three trees were established. According to notifications issued by the Ministry of Agriculture and Commerce of the Korean Empire in 1910 and the Governor-General of Chosen in 1912, Hwa-mok(white birch) was renamed asJajak-namu. In 1968, Beot-namu(Sargent cherry) retained its original name, and Jajak-mok(Korean birch) was remained . In modern Chinese character dictionaries, the meaning of 樺(hwa) is listed as "1. Beot-namu(Sargent cherry), 2. Jajak-namu(white birch)." From this, we can infer the historical background in which the names of these three trees were mixed up.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.413-416
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• 2009

The sap of the white birch is one of the most widely used herbal medicines to treat gastrointestinal tract, jaundice, and various periodontal diseases. The purpose of this study was to measure the effect of white birch sap on in vivo immune agents in mice. The treatment of white birch sap on the forced swimming test has been used as a screening model for new immune enhancement agents. The hematological examination was significantly different in neutrophil, lymphocyte, and monocyte counts between treatment and control groups. Moreover the white birch sap changed the phagocytic index, immobility duration time, and leukocyte counts in mice.

• Asian Journal of Atmospheric Environment
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• v.6 no.3
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• pp.192-205
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• 2012

The effects on birch (Betula spp.) of elevated carbon dioxide ($CO_2$) and ozone ($O_3$), which are both increasing in the troposphere, are surveyed in detail based on the literature. Birches establish themselves in the open field after disturbances, and then become dominant trees in temperate or boreal forests. Ecophysiological approaches include the measurement of photosynthesis, biomass, growth, and survival of seedlings and trees. Elevated $CO_2$ levels give rise to a net enhancement of the growth of birch trees, whereas high $O_3$ generally reduces growth. Although the effects of the two are opposed, there is also an interactive effect. Basic physiological responses of the single genus Betula to $CO_2$ and $O_3$ are set out, and some data are summarized regarding ecological interactions between trees, or between trees and other organisms.