An electroless deposition method was used to modify the surface properties of rice husk ceramic particles (RHC) by depositing nano-nickel on the surface of the RHC (Ni-RHC). The dry tribological performances of aluminum matrix composite adobes containing different contents of RHC and Ni-RHC particles have been investigated using a micro-tribometer. Results showed that the Ni–RHC particles substantially improved both the friction and wear properties of the Ni-RHC/aluminum matrix adobes. The optimal concentration was determined to be 15 wt% for both the RHC and Ni–RHC particles. The improvements in the tribological properties of aluminum adobes including the Ni-RHC were ascribed to frictioninduced peeling off of Ni coating and formation of protection layer on the wear zone, both of which led to low friction and wear volume.
In this research, a novel and efficient quinoline thioacetamide functionalized magnetic graphene oxide composite (GO@Fe3O4@QTA) was synthesized and utilized for dispersive magnetic solid phase preconcentration of Cd(II) and Ni(II) ions in urine and various food samples. A number of diverse methods were employed for characterization of the new nanosorbent. The design of experiments approach and response surface methodology were applied to monitor and find the parameters that affect the extraction performance. After sorption and elution steps, the concentrations of target analytes were measured by employing FAAS. The highest extraction performance was achieved under the following experimental conditions: pH, 5.8; sorption time, 6.0 min; GO@Fe3O4@QTA amount, 17 mg; 2.4 mL 1.1 mol L-l HNO3 solution as the eluent and elution time, 13.0 min. The detection limit is 0.02 and 0.2 ng mL-1 for Cd(II), and Ni(II) ions, respectively. The accuracy of the new method was investigated by analyzing two certified reference materials (sea food mix, Seronorm LOT NO 2525 urine powder). The interfering study revealed that there are no interferences from commonly occurring ions on the extractability of target ions. Finally, the new method was satisfactorily employed for rapid extraction and determination of target ions in urine and various food samples.
Adsorption is one of the best methods for wastewater purification. The fact that water quality is continuously decreasing requires the development of novel, effective and cost available adsorbents. Herein, a simple procedure for the preparation of a magnetic adsorbent from agricultural waste biomass and ferrofluid has been introduced. Specifically, ferrofluid mixed with wheat straw was directly pyrolyzed either by microwave irradiation (900 W, 30 min) or by conventional heating (550°C, 90 min). Magnetic biochars were characterized by X-ray powder diffraction, Mössbauer spectroscopy, textural analysis and tested as adsorbents of As(V) oxyanion and cationic methylene blue, respectively. Results showed that microwave pyrolysis produced char with high adsorption capacity of As(V) (Qm= 25.6 mg g–1 at pH 4), whereas conventional pyrolysis was not so effective. In comparison to conventional pyrolysis, one-step microwave pyrolysis produced a material with expressive microporosity, having a nine times higher value of specific surface area as well as total pore volume. We assumed that sorption properties are also caused by several iron-bearing composites identified by Mössbauer spectroscopy ([super] paramagnetic Fe2O3, α-Fe, non-stoichiometric Fe3C, γ-Fe2O3, γ-Fe) transformed from nano-maghemite presented in the ferrofluid. Methylene blue was also more easily removed by magnetic biochar prepared by microwaves (Qm=144.9 mg g–1 at pH 10.9) compared to using conventional techniques.
Pollution of chloride ion-reinforced concrete can trigger active corrosion processes that reduce the useful life of structures. Multifunctional materials used as a counter-electrode by electrochemical techniques have been used to rehabilitate contaminated concrete. Cement-based pastes added to carbonaceous material, fibers or dust, have been used as an anode in the non-destructive Electrochemical Chloride Extraction (ECE) technique. We studied the performance of the addition of Carbon Fiber (CF) in a cement-graphite powder base paste used as an anode in ECE of concretes contaminated with chlorides from the preparation of the mixture. The experimental parameters were: 2.3% of free chlorides, 21 days of ECE application, a Carbon Fiber Volume Fraction (CFVF) of 0.1, 0.3, 0.6, 0.9%, a lithium borate alkaline electrolyte, a current density of 4.0 A / m2 and a cement/graphite ratio of 1.0 for the paste. The efficiency of the ECE in the traditional technique using metal mesh as an anode was 77.6% and for CFVF of 0.9% it was 90.4%, with a tendency to increase to higher percentages of the CFVF in the conductive cement-graphite paste, keeping the pH stable and achieving a homogeneous ECE in the mass of the concrete contaminated with chlorides.
The effects of cold storage temperature and exposure duration on immature stages of spotted-wing drosophila (SWD) Drosophila suzukii (Diptera: Drosophilidae) on ‘Campbell Early’ grapes were examined to establish a phytosanitary control method. The immature stages (eggs, larvae and pupae) of SWD were all dead after a 6-day cold treatment at 1°C and 8-day cold treatment at 1.5 and 2°C. Small-scale tests using pupae, which were the most-cold tolerant stage, confirmed the validity of the selected temperature and exposure durations. Conversely, the 8- and 10-day at 1°C treatments showed 100% mortality, suggesting that these treatments can guarantee quarantine security against infestations of SWD on exported ‘Campbell Early’ grapes.
Matsucoccus thunbergianae is the main forest insect pest of the Japanese Black Pine (Pinus thunbergii) in the west, south and east coast of South Korea. The main damage pattern appears to be the cumulative damage over many years by the second instar fixed under the pine bark. The adult male has a pair of wings and is attracted sex pheromone emanating from the adult female so that during the mating period (Generally, middle period of March) adult male is attracted to the adult female which has no wing. Using this mating behavior from the adult male, we developed sex pheromone trap to reduce mating success rate by reducing the density of the adult male in the field. In this study, In the indoor induction experiments and the field experiments, sex pheromone trap showed high induction effect on the adult male. Thus, we expect to reduce the damage to the Japanese Black Pine by Matsucoccus thunbergianae.
Bursaphelenchus xylophilus (Bx) is the main plant-parasitic nematode of the Japanese Black Pine (Pinus thunbergii), Red Pine (Pinus densiflora) and Korean Pine (Pinus koraiensis) in the South Korea. Until now, the nematode morphological classification or PCR method using specific marker of Bx were used for the diagnosis of pine wilt disease. However, both methods have a disadvantage that these take a long time to confirm the result. Thus, these methods can not be used quickly at the newly damaged regions. For above the reasons, we had been developed the diagnostic method for Bx combining direct gDNA extraction buffer (DAP) with Recombinase Polymerase Amplification (RPA). This method is able to directly use mixed lysates extracted from Bx-infected pinewood by DAP buffer as gDNA template to RPA without another process for increase gDNA yield. Together, our method is able to detect Bx within 20 mins.
벗초파리는 우리나라에서는 심각한 해충으로 인식되지 않아 발생 기간 및 패턴, 기주 범위 등의 생태적인 연구뿐만 아니라 모니터링을 위한 우수 유인제 및 트랩의 연구도 제한적으로 수행된 실정이다. 본 연구는 기존 연구 결과를 참조하여 사과식초 함유 유인제 2종과 화학적 루어 2종 그리고 트랩 2종에 대한 선발 시험을 수행하였다. 선발 시험은 사육중인 벗초파리를 이용한 choice test와 함께 수목원, 딸기 농장, 블루베리 농장에서의 6반복 유인력 검증 실험을 수행하였다. 유인력 비교 결과 ACV + wine의 포획량이 높았으며, 블루베리 농장 인근 결과값은 전체 조사 항목에서 통계적 유의성을 보였다 (P < 0.05). 트랩 선발 실험 결과 모든 실험 장소에서 Dreves 트랩이 높은 포획량을 보였다. 이상의 결과를 통해 ACV + wine과 Dreves 트랩 조합을 선발하였으며, 이를 이용하여 향후 지속적인 모니터링, 월동 발생 조사 등의 연구에 활용할 수 있을 것으로 생각된다.
Metcalfa pruinosa was first reported in 2009 in Gimhae persimmon farms in Korea, and in Chungnam province in 2011, they first occurred in Dangjin and Taean. M. pruinosa adults are known to lay eggs among the crevices beneath the bark of the host plants, and they are reported to lay mainly on Robinia pseuroacacia trees. However, in order to solve the problem that the time and effort are too much to investigate by moving the 10 cm branch of R. pseudoacacia and removing the whole bark, we investigated the number of wintering eggs at different parts of branches from R. pseudoacacia and surveyed occurrence of them in Chungnam province. 14.5 times and 5.4 times more eggs were observed in the hair tissues of the twigs and thorms bases than the surface of R. pseudoacacia trees, respectively. There was no difference in the number of branches according to the thickness of branches. M. pruinosa in Chungnam province were mainly occurred in Taean, Geumsan and Dangjin, and showed patterns that occurred mainly in highways.
Plant quarantine is preventing the introduction and adaption of exotic pests in homeland, and then eventually promoting and improving domestic agriculture and forestry. Therefore, we conducted a survey of intercepted pests on hand-carried plants from all over the world to Korea. Totally 7,291 of hand-carried plants had been inspected by quarantine inspectors at 2017. Gimpo, Daegu, and Incheon International Airport showed more inspection cases than other areas by November 10, 2017, meanwhile, Gimhae and Incheon International Airport and Incheon Harbor showed more intercepting pest rate than other areas. In Animal and Plant Quarantine Agency, inspector found 490 cases of intercepted pests on 32 countries including China with 116 imported goods.
Craspedoxantha genus has been distributed in worldwide as 7 species in Afrotropical and 2 species in Oriental Regions. It is generally known that C. marginalis is preferred Asteraceae including Vernonia spp. for host plant. However, C. marginalis was first found in cut-flower of Phaenocoma prolifera, which was imported from South Africa, under the plant quarantine inspection in Korea. Therefore, we first report that P. prolifera as a new host plant for C. marginalis and provide information of the morphological characteristics and DNA barcoding sequences on male and female for identification.
The genus Centistes Haliday is a cosmopolitan group, comprising 89 species (Yu et al., 2016; Aguirre et al., 2017). Among them 41 species have been known from the East Palaearctic region (Yu et al., 2016). Centistes are known to be solitary koinobiont endoparasitoids of final instar larvae (rarely) and Coleopteran adults, particularly the families Anthicidae, Carabidae, Chrysomelidae, Coccinellidae, Curculionidae, and Staphylinidae (Loan, 1964; 1972; Shaw, 1985; Chen and Achterberg, 1997). Previously, 16 Korean species of the genus have been investigated by several researchers (Papp, 1994; Belokobylskij, 2000a; 200b; Ku et al., 2001; Lee et al., 2016). In this study, two species of Centistes are reported for the first time from Korea: Centistes minutus Chen & Achterberg, C. sylvicola Belokobylskij. Diagnosis and photographs are provided for each species.
Mirinae is the most diverse subfamily within the family Miridae (Hemiptera: Heteroptera), and includes more than 4,000 species. In Korea, mirids were first recorded from Jeju Island in the mid-1960s. Since that study, numerous plant bug species from the Korean peninsula have been newly recognized and described. Previously, 101 species of Mirini were recorded from Korean peninsula. In this study, we provide an additional information of Mirini in Korea with a description of new species and new records.
Phospholipase A2 (PLA2) hydrolyzes fatty acids from phospholipids at sn-2 position. Two immune-associated PLA2s are known in Spodoptera exigua. Both are calcium-independent cellular PLA2 (iPLA2A and iPLA2B). These iPLA2s are inducible to immune challenge using different epitopes such as virus, Gram+, Gram- bacteria, and fungi. However, their expression profiles are different between these two iPLA2s. Especially, immune challenge with Gram+ bacteria and fungi significantly up-regulated these iPLA2 expression, suggesting their expression under Toll signal pathway. RNA interferences of Toll or IMD signal components are being investigated.