• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.1
• /
• pp.459-467
• /
• 2016

Recently, new open-cut modular construction method, which is built within a 5~7m depth below the road, was proposed for the near-surface transit system to ensure the economic feasibility of underground structures. In this paper, the precast modular construction method was developed for the low-cost and rapid construction of underground structures. For the experiment on the flexural performance of the modular slab connections, a total of eleven specimens were fabricated according to the test variables; section shape, joint type, lap length, and transverse reinforcement. The test results were compared with those of the specimens without loop joints. To verify the performance of the slab connections, the 4-point loading tests of precast RC members with loop joints were conducted. As a result of the test, the flexural performance of the half-depth specimens with a 200mm lap length of loop joints were confirmed to be similar to those of the specimens without joints.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.5
• /
• pp.723-729
• /
• 2013

This paper presents an parallel type Linear Induction Motor with ununiform airgap for a shallow-depth underground train with 100‰ grade and 15 m curvature. This parallel type LIM has enough gradability but has inherently ununiform airgap between center and end parts. Consequently, performance when the train passes curved section should be considered with transient analysis. Moreover, general parallel operation, 1C2M which is usually used for train operation, deteriorates LIM performance because of different line velocity between inner and outer LIMs. Transient analysis has many problems such as huge model, lots of meshes, very long calculation time, truncation error and so on. This paper has presented a novel technique using equivalent linear rotating model in order to solve these problems and has analyzed parallel type LIM by using the proposed technique. Finally, LIM performance according to independent operating control has been investigated.

• Journal of Nutrition and Health
• /
• v.40 no.5
• /
• pp.428-434
• /
• 2007

Cham-dang-gui (Angelica gigas nakai) has been used in traditional Korean medicine to treat hemotological disorders. The purpose of this study is to investigate the hematological effects of water extracts of Cham-dang-gui in rats with anemia induced by iron-free diets. Rats were divided into two groups, a regular diet group (RD) and an iron-free diet group (FeD). The iron-free diet group was then subdivided into the following three treatment groups: saline (1.0 ml/kgBW/day, FeDS), Cham-dang-gui (1.0 g/kgBW/day, FeDA), and iron (iron succinylate 14 mg/kgBW/day, FeDFe) groups. Rats were fed an iron-free diet for 6 weeks to induce iron-deficient anemia, and subsequently underwent the treatments, during which they were fed an iron-free diet for 3 weeks followed by a regular diet for 3 weeks. Body weights of the iron-diet groups (FeDS, FeDA, FeDFe) were lower than that of RD group. The blood levels of Hgb, Hct, MCV, MCH and TIBC were significantly higher in RD and FeDFe groups than those of other groups. The water extract of Cham-dang-gui with iron-free diet has no hematological effects. A regular diet followed by iron-free diets significantly increased blood levels of Hgb, Hct, and MCH.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.2 no.2
• /
• pp.53-68
• /
• 1997

Lake Shihwa, artificially constructed since 1988, shows a typical two-layered system depending on strong haline density stratification. Sill of the water gate at 6 m depth greatly restricts physical mixing with outer seawater and circulation in the lake, and contributes to the enhancement of anoxic environment in the deeper layer. With this enclosed physical environment, Lake Shihwa receives enormous amounts of organics, ammonia, and other pollutants from the neighboring municipal and industrial complexes through six major streams, thus developing biogeochemical differentiation of anoxic to suboxic environment in the high saline bottom water and highly eutrophicated brackish surface water. This study investigated vertical structures, biogeochemical behaviors and processes of various organic and inorganic compounds around oxic-anoxic interface. Nitrite and nitrate rapidly decreased below the pycnocline where about $1{\times}10^8$ tons of hypoxic bottom water exist. In this bottom layer, ammonium ranged from 75 to 360 ${\mu}M$ mainly resulting from deamination of dissolved organic nitrogen and ammonification of precipitated organic particles. Despite large amounts of surface water discharge and dilution by outer seawater inflow about $3{\times}10^8$ tons from April to August, 1996, bottom layer did not show any improvement of water quality and maintained highly reduced environment. The main reason seems to be imbalance between ineffectiveness of dilution due to shallow depth and large surface area, overloaded POC influx from the eutrophicated surface biological activity, and poor replenishment of oxygen in this artificial lake system. Therefore, as long as current salinity dependent two-layered system maintains with its physical limitations, any improvement of water quality cannot be foreseen in Lake Shihwa.