• Journal of Mushroom
• /
• v.15 no.4
• /
• pp.202-205
• /
• 2017

The potential risk of heavy metals and residual pesticides in imported sawdust media inoculated with oak mushroom cultures is a concern for safe mushroom production in Korea. To obtain preliminary data for a sound analysis of this risk, this study was undertaken to analyze the presence of heavy metals and residual pesticides in the oak mushroom media imported from six different regions in China, between 2013 and 2015. Lead, arsenic, chrome, mercury, and cadmium were analyzed; arsenic, chrome, and mercury were not detected. Lead was detected in the imported oak mushroom media from Jinlin, Shandong, Liaoning, and Tianjin. The detection level of lead ranged from 1.7 to 3.2 mg/kg. Cadmium was detected at a level of 0.028 to 0.037 mg/kg in the media from Shandong and Liaoning. No residual pesticides were detected in any of the samples.

• The Journal of the Petrological Society of Korea
• /
• v.7 no.1
• /
• pp.15-26
• /
• 1998

The Dabie-Sulu ultra-high pressure metamorphic (UHPM) zone is commonly suggested to be a collisional belt between the Sino-Korea craton (North China craton) and Yangtze craton (Zhai and Cong, 1996). Two important questions in formulating the tectonic evolution of the northeast Asia are : (1) the boundary between the UHPM zone and the Sino-Korea craton in the Shandong peninsula and (2) the extension of this Chinese UHPM zone into the Korean peninsula. There have been different opinions on the boundary between UHPM zone and the Sino-Korea craton in the Shandong peninsula. For example, the boundary has been suggested to be the Tan-Lu fault (Bai et al., 1993; Wang and Cong, 1996), or Wulian-Rongcheng fault (Cao et al., 1990). Our recent study finds out new evidences, indicating that the possible boundary is the Kunyushan granitoid complex zone, which occurs along the Wulian-Muping fault. Our new evidences are : (1) the basic rocks west to the Kunyushan granitoid zone are high-pressure granulites rather than eclogites (Zhai, 1996) with their Sm-Nd isotopic ages of 1750 Ma and 2788 Ma, representing their retrograde metamorphic and petrogenetic ages, respectively (Li et al., 1997b); (2) the orthogneisses west to the Kunyushan granitoid zone yield 2600-2900 Ma zircon ages and 1600-2020 Ma Rb-Sr and chemical U-Th-total Pb ages, with no younger data (Enami et al., 1993; Ishizaka et al., 1994), having a typical characteristic for the early Precambrian rocks in the Sino-Korea craton; (3) the orthogneisses east to the Kunyushan granitoid zone have 110-320 Ma isotopic ages with a peak value of 180-230 Ma, showing a typical characteristic of metamorphic rocks in the UHPM zone; (4) the Kunyushan granitoid zone consists of numerous granitic bodies, stocks and veins, which have 1900-2000 Ma, 610-710 Ma and 124-180 Ma istotopic ages indicating a long and complicated evolution history of this granitoid zone. There are many lenses and enclosures of metamorphic rocks from the Sino-Korea craton and Sulu UHPM belt in the Kunyushan granitoid zone. Zhai et al. (1998) have defined the Kunyushan granitoid zone as the Jiaodong Boundary complex zone. Some geologists suggested that the UHPM zone extend eastward to the Korea peninsula (Yin and Nie, 1993; Wang and Cong, 1996) and possibly to the Imjingang belt (Chang, 1994; Ree et al., 1996). Unfortunately, there has not been a conclusive evidence indicating that UHPM rocks occur in the Korea peninsula. In this regard, it becomes more important to compare metamorphic rocks in the Shandong peninsula with those in northern and southern Korea peninsula.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.12 no.4
• /
• pp.273-278
• /
• 2009

Overtopping Wave Energy Convertor (OWEC) is an offshore wave energy convertor for collecting the overtopping waves and converting the water pressure head into electric power through the hydro turbines installed in the vertical duct which is fixed in the sea bed. The numerical wave tank based on the commercial computational fluid dynamics code Fluent is established for the corresponding analysis. Several incident wave conditions and shape parameters of the overtopping device are calculated. The straight line type and parabolic type of the sloping arm are compared in the optimal designing investigation of the overtopping characteristics and discharge for OWEC device. The numerical results demonstrate that the parabolic sloping arm is available for wave running up and the overtopping discharge increasing.

• Journal of Environmental Science International
• /
• v.23 no.2
• /
• pp.249-259
• /
• 2014

This paper investigates the characteristics of high $PM_{2.5}$ episodes occurred at Anmyeondo area in spring time, 2009. The monthly mean $PM_{2.5}$ concentration during April was the highest in the year and especially, high levels of $PM_{2.5}$ exceeding standard regulation level were sustained consecutively during 5 to 13 April. To analyze more detailed $PM_{2.5}$ characteristics, numerical simulations were carried out using CMAQ(Community Multi-scale Air Quality) with IPR(Integrated Process Rate) and DDM-3D(Decoupled Direct Method). $PM_{2.5}$ level was lower in daytime than that in nighttime due to vigorous vertical mixing during daytime. The chemical composition was showed that ratio of primary ion components such as sulfate($SO_4{^{2-}}$), nitrate($NO_3{^-}$) and ammonium($NH_4{^+}$) were nearly half of total amount of $PM_{2.5}$. Aerosol and transport process dominantly contributed to $PM_{2.5}$ concentration in Anmyeondo area and contribution rate of local emissions was nearly zero since Anmyeondo area has rare anthropogenic PM emission sources. DDM-3D analysis result showed that $PM_{2.5}$ in Anmyeondo area was influenced by emissions from Shanghai and Shandong region of China.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.13 no.2
• /
• pp.91-98
• /
• 2010

The water elevation inside the air chamber and bi-directional air flow in the duct of Oscillating Water Column wave energy converter is one of the most important factors to evaluate the operating performance. The numerical wave tank based on the commercial software Fluent 6.2 in the present paper is employed to generate the incident waves. The numerical wave tank consists of the continuity equations, the Reynolds-averaged Navier-Stokes equations and the two-phase VOF function. The oscillating amplitude of water column in the chamber and bi-directional air flow in the duct installed on the top of the chamber are calculated, and compared with experimental data to verify the validation of the present NWT. The nozzle effects of the chamber-duct system on the relative amplitudes of the inner free water surface and air flow rate in the duct are investigated.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.15 no.2
• /
• pp.111-117
• /
• 2012

Oscillating water column is the most widely used ocean energy converting systems all over the world. The operating performance is influenced by the efficiencies of the two converting stages in the OWC chamber-turbine integrated system. In order to consider the effects of the turbine, the orifice model are carried out. The VOF based Numerical Wave Tank (NWT) is utilized to simulate the water column oscillation inside the chamber and the results are compared with corresponding experimental data. This paper reviews the state of the art in interaction among wave elevation inside the chamber and air flow rate in the duct, which are considered the turbine effects. Effects of incident wave conditions and several shape parameters on the operating performance of OWC chamber are investigated numerically. The effects of the impulse turbine on the integrated system and interaction among the wave elevation, pressure and air flow velocities variations are investigated.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 1999.04b
• /
• pp.386-389
• /
• 1999

Amphoteric polymers have brought to papermakers' attention gradually. In this paper, a series of amphoteric starches with different cationic and anionic degree of substitution (DS) are prepared. Better product has been selected and used under different condition. As retention and drainage aids, amphoteric starches were used in shorter fiber length, weak strength and poor drainage bleached AQ-Soda wheat straw pulp. In neutral and alkaline papermaking system, when amphoteric starches contain 0.024-0.026 anionic degree of substitution (DS), it is shown that the higher the cationic degree of substitution (DS) in amphoteric starches, the better the filler retention. The filler retention is improved 12.5%, 30.3%, and 35.1% and 32.5% respectively by adding 1% amphoteric starch LS-L2 -1 (0.034), LS-L2-2 (0.040), LS-L2-3 (0.047) and LS-L2-4 (0.052). But the strength of handsheets if affected a little. By adding 2% Al2 (SO4)3 and 1.5% LS-L2-3 at pH 7.5, filler retention can be improved from 38% to 80%, and breaking length of sheet only decreases 3.2%. As dry strengthening aids, amphoteric starches were used in eucalyptus APMP. Amphoteric starches are used in eucalyptus APMP. The amphoteric starch LS-L2-2 is better dry strength aid. Adding 1% LS-L2-2 can improve breaking length 24.5%, burst index 42.9%, tear index 38.8%, folding endurance and density of the handsheets.

• Journal of the Korean Society of Costume
• /
• v.60 no.5
• /
• pp.106-116
• /
• 2010

The purpose of this study was to investigate the image evaluation of chinese female college students according to coloration of dress shirt and necktie and necktie width. The experimental materials developed for this study were a set of stimulus and response scales. The stimuli were 12 color pictures, in which the hue(red, blue), tone(lt-shirt/dk-tie, dk-shirt/lt-tie), and necktie width(narrow, medium, width) were manipulated. The 7-point scale was used for evaluation of image. The subjects of this research were 120 chinese female college students living in Shandong, China. The investigation was carried out at April-May 2009. The data were analyzed by using SPSS program. Analysis methods were ANOVA and Duncan-test. The results of this study were as follows.; The analyses of image according to coloration of dress shirt and necktie and necktie width revealed that the concerned factors are four characteristic dimensions of ability-elegance, youth-attractiveness, appeal, and warmness. Hue showed an independent effect on ability-elegance, appeal, and warmness. Tone showed an independent effect on appeal and warmness. Necktie width showed an independent effect on appeal. In addition, interaction effects of hue and tone on ability-elegance were found. Interaction effects of hue and necktie width on appeal were found. Interaction effects of tone and necktie width on youth-attractiveness were found.

• Journal of Power Electronics
• /
• v.18 no.3
• /
• pp.841-852
• /
• 2018

This paper presents a dual-algorithm search method (GWO-GSO) combining grey wolf optimization (GWO) and golden-section optimization (GSO) to realize maximum power point tracking (MPPT) for photovoltaic (PV) systems. First, a modified grey wolf optimization (MGWO) is activated for the global search. In conventional GWO, wolf leaders possess the same impact on decision-making. In this paper, the decision weights of wolf leaders are automatically adjusted with hunting progression, which is conducive to accelerating hunting. At the later stage, the algorithm is switched to GSO for the local search, which play a critical role in avoiding unnecessary search and reducing the tracking time. Additionally, a novel restart judgment based on the quasi-slope of the power-voltage curve is introduced to enhance the reliability of MPPT systems. Simulation and experiment results demonstrate that the proposed algorithm can track the global maximum power point (MPP) swiftly and reliably with higher accuracy under various conditions.

• Journal of the Korean Regional Science Association
• /
• v.15 no.2
• /
• pp.21-38
• /
• 1999

This paper is concerned with analyzing the role of Northeast Asia intercity networks in Northeast Asia in creating regional networks. For the purpose of this paper, we have followed Choe's (1996) definition of Northeast Asia which includes the Russian Fat East, the Northeast region of China, South Korea, North Korea and Japan. The central hypothesis of the paper is that the geopolitical conditions of Northeast Asia compared for example with Southeast Asia, favor bilateral rather than multilateral linkages between nation states. In these circumstances, it is our hypothesis that cities will play an important role in developing a "local image" of regio-nalism and intercity networks. In order to analyze this hypothesis, the paper is divided into three parts. Part A analyzes the emerging urban system of the Northeast Asia region using Choe's concept of the BESETO corridor and updating his data from the late 1980s to the mid 1990s just prior to the financial crisis. This analysis is further supported by the analysis of economic and transportation linkages within the urban system of the region with some discussion of emerging urban nodes. Part B looks at the specific case studies of the region including the Bohai Sea region, the Japan Sea and case studies of Sapporo, the Japan Sea and case studies of Sapporo, Pusan and Shandong province cities. Part C summarizes this preceding analysis and that the development of regionalism and servicing urban nodes is move likely to emerge from a myriad of linkages developed between the region's cities than from a supra-regional role of nation states. This finding has important implications for regional policy formation suggesting that there should be considerate national support for international linkages between cities.en cities.