• Journal of Aerospace System Engineering
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• v.17 no.2
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• pp.26-37
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• 2023

Urban air mobility (UAM) is being developed as part of the next-generation aircraft, which could be a viable solution to entrenched problems of urban traffic congestion and environmental pollution. A new airport platform called vertiport as a space where UAM can take off and land vertically is also being introduced. Noise regulations for UAM will be strict due to its operation in a highly populated urban area. Ground effects caused by vertiport can directly affect aerodynamic forces and noise characteristics of UAM. In this study, ground effects of vertiport on aerodynamic loads, vorticity field, and far-field noise were analyzed using Lattice-Boltzmann Method (LBM) simulation and Ffowcs Williams and Hawkings (FW-H) acoustic analogy with a permeable surface method.

• Development and Reproduction
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• v.5 no.1
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• pp.73-79
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• 2001

Recently many studies have reported that total and bioavailable androgens reduced in male and female athletes and that physical exercise reduces the body weight and increases the reproductive abnormalities such as oligomenorrhea, anovulation, inadequate luteal phase, and delayed puberty in women by the inhibition of the hypothalamic-pituitary-gonadal (HPG) axis . In addition, high mileage endurance 겨nning, psychological stress, and military endurance training in men also reduce the secretion of reproductive hormones. To investigate the efffcts of physical endurance exercise on the secretion of reproductive hormones in men, androgenic hormones from adrenal glands and testis were measured in serum by the conventional radioimmunoassays after long-term (more than3 months), short-term (1 week), and acute (1${sim}$2 hours) physical exercises. Androgenic hormones from adrenal glands and testis such as total testosterone (TT), free testosterone (fT), dehydroepiandrosterone (DHEA), and androstenedione (A) decreased after thesestrenuous endurance trainings, whereas ACTH, cortisol, and dehydroepiandrosterone sulfetes (DHEAS) increased. Conadotropins (LH and FSH) were not idluenced by the physical exercises. Based upon the present results, we assume that the decrease in adrenal and testicular androgens by physical endurance exercises might be associated with the reproductive abnormalities in athletes by unknown factor(s) in addition to the HPG axis disturbance.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.335-341
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• 2011

This paper searched the affect of Water dropwort and Tumeric on radiation exposure. By experimenting 50 male mouse, ICR type 5 weeks old male 25~30g, 5 mouse was divided in to each group respectively. A : 3 Gy control group, B : 5 Gy control group, C : 3 Gy, FW, D : 5 Gy FW, E : 3 Gy LW, F : 5 Gy LW, G : 3 Gy FT, H : 5 Gy FT, I : 3 Gy LT, J : 5 Gy LT FW : Ate Water dropwort before the radiation exposure. FT : Ate Tumeric before the radiation exposure. LW : Ate Water dropwort after the radiation exposure. LT : Ate Tumeric after the radiation exposure. During the 7 day radiation, Control group (A, B) received physiological saline (500mg/kg/day) in oral administration, LW and LT group (E, F, I, J) respectively received Water dropwort or tumeric (500mg/kg/day) in oral administration after the radiation, FW and FT group (C, D, G, H) respectively received Water dropwort or tumeric (500mg/kg/day) in oral administration before the radiation. As a result, an average leukocyte rate on 5 mouse was 200K/${\mu}L$ on group A. 6.46K/${\mu}L$ on group C which was in normal rate range (1.8-10.7 K/${\mu}L$). An average leukocyte rate was 23.33K/${\mu}L$ on group G. which was not normal rate, but compare to 200K/${\mu}L$, it was closer to normal rate. An average lymphocyte rate was 118.87K/${\mu}L$ on Group A. 1.51K/${\mu}L$ on Group G. which was in normal lymphocyte rate range (0.9-9.3K/${\mu}L$). An average thrombocyte rate was 4000K/${\mu}L$ on Group A. 1107 K/${\mu}L$ on Group C. 2759.6 K/${\mu}L$ on Group G. which was in normal thrombocyte rate range (592-2972 K/${\mu}L$). From this result, it was found that when exposed to radiation, Water dropwort and Tumeric have defensive effect in a preventive level. Also from an animal experiment, it was found that blood corpuscle rate returns to a normal rate. Based on this experiment, diverse research on this field should be conducted.

• Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.343-349
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• 2010

The effects of osmotic stress on the non-specific immune response of Nile tilapia, Oreochromis niloticus, were investigated. Osmoregulatory mechanism of tilapia has been studied, but less information is available about innate immune response of O. niloticus faced with hyperosmolality. Acute osmotic stress was elicited by transferring tilapia from freshwater (FW) to 24 psu seawater (SW). Non-specific immune parameters including lysozyme activities of plasma and head kidney (HK), alternative complement pathway (ACP) activity in plasma, phagocytic capacities of spleen and HK immune cells, and respiratory burst activity of immune cells in both HK and spleen were analyzed. Lysozyme activities were increased at 1 h and 30 h after transfer to SW, but decreased at 10 h after SW transfer. Conversely, ACP activity increased 10 h after SW transfer. Phagocytic capacity increased slightly at 1 h and 5 h after SW transfer, and respiratory burst activity showed an increase in superoxide release at 10 h after SW transfer. Taken together, these results indicate that the exposure of tilapia to hyperosmotic conditions has immunostimulatory effects on cellular and humoral immune reactions.

• Journal of the Korean Chemical Society
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• v.38 no.5
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• pp.359-365
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• 1994

The crystal stucture of hexapotassium undecahydrogen tetratungsto hexaantimonate(V) tetrahydrate has been determined from single crystal X-ray diffraction data. Crystal data are as follows: $K_6H_{12}[Sb_6W_4O_{36}]{\cdot}4H_2O$, Fw = 2360.62, tetragonal, I$4_1$/a, a = 10.799(1) ${\AA}$, c = 35.244(5) ${\AA}$, V = 4110.1(7) ${\AA}^3$, Z = 4, $D_x$ = 3.82 g$cm^{-3}$, $\mu(MoK\alpha)$ = 160.15 $cm^{-1}$, T = 293 K, final R = 0.0356 for 2400($F_0 > 3\sigma(F_0))$ independent reflections. The $[H_{12}Sb_6W_4O_{36}]^{-6}$ polyanion independently consists of one tungsten, two antimony, and nine oxygen atoms and belongs to the $\bar4(S_4)$ point group. This polyanion is formed by two open octahedra five membered ring of Sb(3)$O_6-W(1)O_6-Sb(2)O_6-W(1)O_6-Sb(3)O_6$ which is connected at right angle. The Sb-W, Sb-O, and W-O bond distances range from 3.2304(9) to 3.2403(5) $\AA$, 1.745(8) to 2.334(6) $\AA$, and 1.914(7) to 2.039(7) $\AA$, respectively.

• Journal of the Korean Chemical Society
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• v.38 no.6
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• pp.435-441
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• 1994

The inclusion compound constituted with three-dimensional metal-complex $Cd(pn)Ni(CN)_4$ has been prepared and determined the crystal structure from single crystal X-ray diffraction data. Crystal data are as follows: $[Cd(pn)Ni(CN)_4]{\cdot}0.5(CH_3COCH_3{\cdot}H_2O)$, Fw = 387.35, Orthorhombic, $Pn2_1a$, a = 13.950(3) $\AA$, b = 26.713(7) $\AA$, c = 7.628(1) $\AA$, V = 2843(1) $\AA^3$, Z = 4, $D_x=1.81 gcm^{-3}$, $\mu(MoK{\alpha})$ = $28.153 cm^{-1}$, T = 297K, final R = 0.0418 for 3521($F_0>3{\sigma}(F_0)$). The metal-complex host provides tunnel cavity, similar to thiourea inclusion compounds, accommodated guest molecules $(=CH_3COCH_3\;and\;$H_2O).$ The stoichiometric host: guest ratio is 0.5. The title inclusion compound reveals another evidence for the host-selectivity, that is, the branched aliphatic guest molecule leads T-type host structure.

• Journal of Plant Biology
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• v.35 no.4
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• pp.317-322
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• 1992

The nitrogen fixation activity and environmental factors of Lespedeza bicli!oy Turcz, forming annual root nodules by symbiotic Rhizobium sp. were analyzed in the field conditions during the growing period. Seasunal changes of $N_2-fixation$ activity showed the maximum value of $120\;\mu\textrm{M}\;C_2_H4{\cdot}noduie\;g\;fw^{-1}{\cdot}hr^{-1}$ during the active growing period (June) and varied significantly depending on the growth phase and environmental factors. The maximum activities were attained at the conditions of pH 7, $30^{\circ}C$ of temperature, 18 Kpa of oxygen partial pressure and inhibited by water stress and nitrogen sources. The habitat soil was weak acidic and poor in nitrogen, phosphorus and organic matter contents. The leaf area ratios and chlorophyll contents were ranged from 442 to $48;\textrm{cm}^2{\cdot}g\;dw^{-1}$ and from 33 to $38\;\mu\textrm{g}\;chI{\cdot}\textrm{cm}^2$. Nitrogen contents in each organ showed the maximum of 46, 19 and $11\;mg{\cdot}g\;dw^{-1}, respectively for leaf, rool and stem in the early period. The highest phosphorus contents were 4.2, 1.2 and $0.6\;mg{\cdot}g\;dw^{-1}$, respectively for leaf. root and stem in early growing period. The allocation ratios of nitrogen quantity showed 60% for leaves and 73% for roots during the active and late growth period, and 22% [or stems in average. The allocalion ralios o[ phosphorus quantity showed 58% for leaves during the most productive period, 70% for roots in the pre-growth stage and 26% for stems in average.verage.

• KSBB Journal
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• v.20 no.6
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• pp.438-442
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• 2005

Batch experiments were performed to investigate the effects of volumetric mixing ratio(v/v) of two substrates, food wastes(FW) and waste activated sludge(WAS). In batch experiments, optimum mixing ratio for hydrogen production was found at $10{\sim}20$ v/v % addition of WAS. CSTR(Continuous Stirred tank reactor) was operated to investigate the hydrogen productivity and the microbial community under various HRTs and volumetric mixing ratio(v/v) of two substrates. The maximum yield of specific hydrogen production, 140 mL/g VSS, was found at HRT of 2 day and the volumetric mixing ratio of 20:80(WAS:FW). The spatial distribution of hydrogen producing bacteria was observed in anaerobic fermentative reactor using fluorescent in situ hybridization(FISH) method.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.631-639
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• 2011

This research was conducted to investigate potential use of New Zealand spinach (Tetragonia tetragonoides) as a new vegetable crop which will be cultivating in salt-affected soils including reclaimed land. Traditionally New Zealand spinach has been studied to explore functional compound or salt removing potential. To cultivate the crop species in the salt-affected soil widely, it is essential to obtain salt and soil texture responses under the controlled environment. Fifty nine New Zealand spinach ecotypes native to Korean peninsula first collected over seashore areas, and primitive habitat soil environment was evaluated by analyzing soil chemical properties from 32 locations. Different textures of sandy, silt loam, and sandy loam soils were prepared from nearby sources of sea shore, upland and paddy soils, respectively. Target salinity levels of 16.0 dS/m, 27.5 dS/m, 39.9 dS/m, and 52.4 dS/m in electrical conductivity (ECw) were achieved by diluting of 25, 50, 75, 100% (v/v) sea water to tap water (control, 0.6 dS/m), respectively. Various measurements responding to soil texture and irrigation salinity included plant height, root length, fresh weight (FW), dry weight (DW), leaf parameters (leaf number, leaf length, leaf width), lateral branching, and inorganic ion content. was found to adapt to diverse habitats ranging various soil chemical properties including soil pH, organic matter, exchangeable bases, EC, and cation exchange capacity (CEC) in Korea. Responding to soil texture, New Zealand spinach grew better in silt loam and sandy loam soil than in sandy soil. Higher yield (FW and DW) seemed to be associated with branch number (r=0.99 and 0.99, respectively), followed by plant height (r=0.94 and 0.97, respectively) and leaf number (r=0.89 and 0.84, respectively). Plant height, FW, and DW of the New Zealand spinach accessions were decreased with increasing irrigation salinity, while root length was not significantly different compared to control. Based on previous report, more narrow spectrum of salinity range (up to 16 dS/m) needs to be further studied in order to obtain more accurate salinity responses of the plant. As expected, leaf Na content was increased significantly with increasing salinity, while K and Ca contents decreased. Growth responses to soil texture and irrigation salinity implied the potential use of New Zealand spinach as a leafy vegetable in salt-affected soil constructed with silt loam or sandy loam soils.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.9
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• pp.1278-1284
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• 2017

Objective: To assess the potency of calcium propionate (CAP) used as silage additive, an experiment was carried out to evaluate the effect of CAP on the nitrogen transformation, fermentation quality and aerobic stability of alfalfa silages. Methods: Alfalfa was ensiled with four levels of CAP (5, 10, 15, and 20 g/kg of fresh weight [FW]) in laboratory silos for 30 days. After opening, the silages were analyzed for the chemical and microbiological characteristics, and subjected to an aerobic stability test. Results: The increasing proportion of CAP did not affect pH, lactic acid (LA) concentrations and yeast counts, while linearly decreased counts of enterobacteria (p = 0.029), molds (p<0.001) and clostridia (p<0.001), and concentrations of acetic acid (p<0.001), propionic acid (p<0.001), butyric acid (p<0.001), and ethanol (p = 0.007), and quadratically (p = 0.001) increased lactic acid bacteria counts. With increasing the proportion of CAP, the dry matter (DM) loss (p<0.001), free amino acid N (p<0.001), ammonia N (p = 0.004), and non-protein N (p<0.001) contents were linearly reduced, whereas DM (p = 0.048), water soluble carbohydrate (p<0.001) and peptide N (p<0.001) contents were linearly increased. The highest Flieg's point was found in CAP10 (75.9), represented the best fermentation quality. All silages treated with CAP improved aerobic stability as indicated by increased stable hours compared with control. Conclusion: The addition of CAP can suppress the undesirable microorganisms during ensiling and exposure to air, thereby improving the fermentation quality and aerobic stability as well as retarding the proteolysis of alfalfa silage. It is suggested that CAP used as an additive is recommended at a level of 10 g/kg FW.