• Journal of Ecology and Environment
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• v.31 no.3
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• pp.167-176
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• 2008

Atmospheric N deposition has far-reaching impacts on forest ecosystems, including on-site impacts such as soil acidification, fertilization, and nutrient imbalances, and off-site environmental impacts such as nitrate leaching and nitrous oxide emission. Although chronic N deposition has been believed to lead to forest N saturation, recent evidence suggests that N retention capacity, particularly in the forest floor, can be surprisingly high even under high N deposition. This review aims to provide an overview of N retention processes in the forest floor and the implications of changing C-N interactions for C sequestration. The fate of available N in forest soils has been explained by the competitive balance between tree roots, soil heterotrophs, and nitrifiers. However, high rates of N retention have been observed in numerous N addition experiments without noticeable increases in tree growth and soil respiration. Alternative hypotheses have been proposed to explain the gap between the input and loss of N in N-enriched, C-limited systems, including abiotic immobilization and mycorrhizal assimilation, both of which do not require additional C sources to incorporate N in soil N pools. Different fates of N in the forest floor have different implications for C sequestration. N-induced tree growth can enhance C accumulation in tree biomass as observed across temperate regions. C loss from forests can amount to or outweigh C gain in N-saturated, declining forests, while another type of 'C-N decoupling' can have positive or neutral effects on soil C sequestration through hampered organic matter decomposition or abiotic N immobilization, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.3
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• pp.185-192
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• 2000

This experiment was canied out to determine the effect of management practices on the quality of round baled oat silage at experimental field of Grassland and Forage Crops division, National Livestock Research Institute, RDA, Suwon from 1997 to 1998. The experiments are consist of randomized block design with 3 replications. The treatments are 3 wilting dates(0, 2 and 4 days), 3 wrap colors(white, black and green and 3 inoculant(untreated, Inoculant A and Inocuant B). The crude protein(CP) content was increased by prolonged wilting periods, but the effect of wrap color and inoculant were not founded. Acid detergent fiber(ADF) and neutral detergent fiber(NDF) content of all silages were not founded significant difference, but in vitro dry matter digestibility of oat silage with inoculant was significantly higher compare with control. Wilting treatment increased the mean silage acidity compare with control and inoculant treatment significantly reduced silage acidity. Wrap color did not influence the silage acidity. Wilting or inoculant treatments increased lactic acid content but, decreased the content of acetic and butyric acid. The quality grade of all silage were grade 3, except inoculant treated silage. Wilting or inoculant decreased silage DM loss, but wrap color did not effect on siage DM loss. The result of this study indicate that wilting for 2-4 days and inoculant will improve the silage fermentation and quality of round baled oat silage. (Key words : Oat, Wilting, Inoculant, Wrap color, Round bale silage)

• Journal of The Korean Astronomical Society
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• v.48 no.2
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• pp.113-123
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• 2015

We present observational results from optical long-slit spectroscopy of parsec-scale jets of DG Tau. From HH 158 and HH 702, the optical emission lines of Hα, [O i] λλ6300, 6363, [N ii] λλ6548, 6584, and [S ii] λλ6716, 6731 are obtained. The kinematics and physical properties (i.e., electron density, electron temperature, ionization fraction, and mass-loss rate) are investigated along the blueshifted jet up to 650′′ distance from the source. For HH 158, the radial velocity ranges from −50 to −250 km s⁻¹. The proper motion of the knots is 0.′′196 − 0.′′272 yr⁻¹. The electron density is ∼10⁴ cm⁻³ close to the star, and decreases to ∼10² cm⁻³ at 14′′ away from the star. Ionization fraction indicates that the gas is almost neutral in the vicinity of the source. It increases up to over 0.4 along the distance. HH 702 is located at 650′′ from the source. It shows ∼ −80 km s⁻¹ in the radial velocity. Its line ratios are similar to those at knot C of HH 158. The mass-loss rate is estimated to be about ∼ 10⁻⁷ M_⊙ yr⁻¹, which is similar to values obtained from previous studies.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.5
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• pp.410-420
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• 2015

This paper provides a comparison of power converter loss and thermal description for voltage source and current source type 5 MW-class medium-voltage topologies of wind turbines. Neutral-point clamped three-level converter is adopted for a voltage source type topology, whereas a two-level converter is employed for current source type topology, considering the popularity in the industry. To match the required voltage level of 4160 V with the same switching device of IGCT as in the voltage source converter, two active switches are connected in series for the case of current source converter. Transient thermal modeling of a four-layer Foster network for heat transfer is done to better estimate the transient junction and case temperature of power semiconductors during various operating conditions in wind turbines. The loss analysis is confirmed through PLECS simulations. Comparison result shows that the VSC-based wind turbine system has higher efficiency than the CSC under the rated operating conditions.

• Korean Journal of Food Science and Technology
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• v.11 no.3
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• pp.188-191
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• 1979

The heat decomposition rate of guanosine-5'-monophosphate was investigated in pH range from 5.52 to 7.00, and 0.1 of the ionic strength. The result showed that the rate was a first-order reaction and the rate of guanosine-5'-monophosphate loss was maximum near $pKa_2$. The loss of guanosine-5'-monophosphate was temperature dependent and followed to the Arrhenius equation in the temperature region from $93^{\circ}C$ to $108^{\circ}C$. The rate constant as function of temperature ($93^{\circ}C$ to $108^{\circ}C$) and neutral pH($pKa_2$, 6.0, to 7.0) was correlated by least-square fit of the experimental data; $$K=4.19{\times}10^{26}\;{\exp}\;[-1.3(pH+E/RT)]$$

• Journal of the Korean Institute of Gas
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• v.3 no.3 s.8
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• pp.39-44
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• 1999

In the study, corrosion characteristics under various corrosion environments(neutral solution, acid solution), for various hinge materials(SM20C, BsC3 and STC4H), were investigated by immersion test, and the behaviour of fretting wear under atmosphere was studied. In immersion test, corrosion potential of those materials showed to be noble in the sequence of $0.5\%HNO_3$> underground water> $0.5\%\;H_2SO_4$ solution, and potential of a sole material, except BsC3, was more noble than these of mixed materials. In same material SM20C, the fretting wear loss of rotary materials increased about 1.9 times to that of moving materials, because of surface hardening by frictional force.

• Clinics in Shoulder and Elbow
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• v.27 no.1
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• pp.88-107
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• 2024

The aim of this systematic review was to collect evidence on the following 10 technical aspects of glenoid baseplate fixation in reverse total shoulder arthroplasty (rTSA): screw insertion angles; screw orientation; screw quantity; screw length; screw type; baseplate tilt; baseplate position; baseplate version and rotation; baseplate design; and anatomical safe zones. Five literature libraries were searched for eligible clinical, cadaver, biomechanical, virtual planning, and finite element analysis studies. Studies including patients >16 years old in which at least one of the ten abovementioned technical aspects was assessed were suitable for analysis. We excluded studies of patients with: glenoid bone loss; bony increased offset-reversed shoulder arthroplasty; rTSA with bone grafts; and augmented baseplates. Quality assessment was performed for each included study. Sixty-two studies were included, of which 41 were experimental studies (13 cadaver, 10 virtual planning, 11 biomechanical, and 7 finite element studies) and 21 were clinical studies (12 retrospective cohorts and 9 case-control studies). Overall, the quality of included studies was moderate or high. The majority of studies agreed upon the use of a divergent screw fixation pattern, fixation with four screws (to reduce micromotions), and inferior positioning in neutral or anteversion. A general consensus was not reached on the other technical aspects. Most surgical aspects of baseplate fixation can be decided without affecting fixation strength. There is not a single strategy that provides the best outcome. Therefore, guidelines should cover multiple surgical options that can achieve adequate baseplate fixation.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.87-98
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• 1994

Sludge minimization in an water treatment plant can be achieved by optimizing a main water treatment process as well as by enhancing a thickening and a dewatering facilities. In this study, dewatering and drying techniques for reducing the quantity of the water sludge generated from the conventional water treatment plant in the local states were investigated by reducing its water content. Not only the types and dosages of polymers but also the mixing intensity of the mixtures of a concentrated sludge and polymers on the different pH were evaluated for the optimum dewatering conditions of the water sludge. Weight reduction of the water sludge was also tested at a given temperature range. The dewatering efficiency of the water sludge was not affected by the types of polymer but by mixing intensity(GT value) in this study. pH effect on dewaterbility of the water sludge took a major role at the neutral pH range. The optimal polymer dose was 1.5 mg-polymer/g-TSS(about 40mg/L as polymer). Dewaterability was enhanced at a lower mixing intensity(GTbelow 10,000 sec-1). Free water in the void of sludge cake was dried around $100^{\circ}C$, chemical bound water was evaporated around $320^{\circ}C$, and organic material was burned out at the range of 300 to $600^{\circ}C$. Ignition losses of the water sludge were varied 15 to 40 % as the raw water quality. The ignition loss due to the chemical bound water was 10-20% and the loss due to the organic material was 4-20% of the total ignition loss.

• Journal of Pharmaceutical Investigation
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• v.38 no.4
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• pp.229-234
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• 2008

In the present study, chitosan-glycerophosphate sodium salt solution as a thermosensitive system (TSS) was used to formulate a temperature-sensitive drug delivery system (TSDDS) containing acetaminophen (AAP). The optimized TSS was prepared by measuring gelation temperature, gelation time and rheological properties of TSS. The optimized gelation temperature and time of TSS were $36^{\circ}C$ and 100 seconds, respectively. The viscosity of TSS was also suitable for maintaining gel structure at $37.2^{\circ}C$. The release profiles of TSDDS in PBS/pH 7.4 with various apparatuses and mass loss of TSDDS were investigated. The time required to release 50% of AAP from TSDDS ($t_{50%}$) was 120 min with the formation of pore on the surfaces, which was 2 times longer than that from AAP-chitosan gel. In addition, TSDDS was degraded approximately 80% within 4 hr and then degraded slowly for 20 hrs. In conclusion, AAP-TSS (TSDDS) formulated in this study might be suitable for some specific uses such as subcutaneous injection and rectal formulation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.97-100
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• 1997

These days, the raw materials that have the cell recovering effect are used commonly in cosmetics. In this study, six materials were rested for the characteristics of recovering effect both on vivo and in vitro. Tested raw materials were Soypol, 3-APPA, Apple extract, Polygonatum japonicum extract, Scutellarkd baicalensis extract, Aloe extract. Among these materials, Soypol and 3-APPA were synthesized and others were made by extraction at the Pacific R&D Center. Human forearm skin and cultured skin cell were damaged by sodium lauryl sulfare and then raw materials were applied for open treatment on SLS damaged human skin or cells. The recovering effects of raw materials in vivo were evaluated by measuring transepidermal water loss, skin hydration and erythema and in vitro effects of proliferationg cells were assessed by neutral red uptake assay. In the in vivo study, only the evaluation by TEWL showed correlation with the visual score. Our of six materials, 3-APPA had the most positive effect in both in vivo and in vitro studies and the correlation was r=0.8286 (p=0.042).