2022년 국내 노지 마늘, 대파, 양파, 부추 작물재배지에서 채집한 파총채벌레 지역집단들에 대하여 살충제 저항성을 조사하였다. 제조사 추천약량에서의 살충력은 acrinathrin SC를 제외한 6종 약제들이 안성 등 8개 집단 에서 모두 90%이상을 보였으며, Spinetoram SC와 fluxametamide EC는 추천농도의 100배 희석농도에서도 전 지역 집단에 걸쳐 높은 살충력을 보여주었다. 미리 저항성 진단농도로 코팅한 바이알을 이용한 지역집단의 저항성 검정을 실시한 결과, emamectin benzoate의 저항성이 신안 등 9개 지역집단에서 매우 높았으며, chrantraniliprole은 부산 등 4개 , spinetoram은 의성 등 3개, actamiprid와 chlorfenapyr는 각각 1개의 지역집단에서 저항성이 높게 발달 하고 있는 것을 확인할 수 있었으며, 지역별로는 주요 대파 및 양파 재배지인 안성, 서산, 진도, 신안 지역의 저항성 이 모든 약제에 대하여 전반적으로 높게 나타났다.

Residual contact vial (RCV) method was used to monitor insecticide resistance in field populations of the melon thrips, Thrips palmi. Median lethal doses (LD50) at 8 h post-treatment of six insecticides (chlorfenapyr, cyantraniliprole, cypermethrin, dinotefuran, emamectin benzoate and spinosad), which are commonly used for T. palmi control, were determined at 8 h post-treatment using a susceptible RDA strain. The diagnostic doses for on-site resistance monitoring of the six insecticides, which were determined as two-fold higher doses of LD90 for the RDA strain, were in the range of 0.299 to 164,25 μg-1cm2. To test the applicability of RCV for T. palmi, insecticide resistance levels in three field populations (Gyeonggi; GG_AS, Chungbuk; CB_CJ, Jeonbuk; JB_KJ) were evaluated. Field populations showed reduced mortality (0-50% mortality) to spinosad, cypermethrin, cyantraniliprole and emamectin benzoate, that they have different degree of resistances to these insecticides. In particular, all test field populations exhibited 0% mortality to spinosad, suggesting wide spread of spinosad resistance in the field. Moreover, no detectable mortality to emamectin benzoate was observed in JB_KJ strain, suggesting uneven distribution of emamectin benzoate resistant population of T. palmi. To provide more precise information on resistance profiles and distribution in T. palmi populations, it would be necessary to conduct a large scale resistance mapping for broad geographical regions.

An easy and rapid resistance detection protocol for the Western flower thrips Frankliniella occidentalis was established based on the residual contact vial bioassay (RCV), in which insecticide resistance levels can be estimated at 8 h-post treatment of diagnostic doses. The RDA strain was used as a reference susceptible strain, which has been reared under laboratory conditions over 10 years without exposure to any insecticides. Seven insecticides were tested for the determination of diagnostic dose. Among them, five insecticides (chlorfenapyr, acrinathrin, spinosad, emmamectin benzoate and thiamethoxam, ranged as 0.03 ~ 0.42 μg-1cm2) were applicable to the RCV. However, two insecticides (omethoate and imidacloprid) were not able to be used for the RCV because the treated inner surface of glass vials by these insecticides were too viscous, causing non-specific mortality. The RCV detection kit was employed for the estimation of resistance levels for the five insecticides in five local populations. Almost field-collected populations revealed high levels of resistance to the four insecticides (acrinathrin, spinosad, emmamectin benzoate and thiamethoxam) by showing less than 50% mortality. The baseline resistance detection by RCV method will facilitate the selection of proper insecticides for farmers to manage insecticide resistant-populations of F. occidentalis.

Establishment of rapid resistance level detection system is essential step to adopt the adaptive management for the control of various kinds of resistant pest population. Here, we established acaricides resistance detection methods based on residual contact vial bioassay (RCV) and quantitative sequencing methods (QS), and applied to determine the resistance levels from several populations in two-spotted spider mite, Tetranychus urticae, which has been considered as major notorious pest in rose cultivation area in worldwide. 12 acaricides were applicable to the RCV among 19 representative acaricides by showing the dose-dependent mortality within 8 hr, suggesting the acaricide suitability for the RCV might be varied by toxicity mechanism in each acaricides. The QS regression was established for 10 point mutations associated with five number of acaricides resistance such as organophosphate, pyrethroid, abamectin, bifenazate and etoxazol. The 95% prediction level was ranged from 10.8±5.4∼92.2±3.2%. The resistance levels were determined by above two detection methods from a total 12 strains. The laboratory-reared populations were revealed high susceptibility with low resistance allele frequencies to some acaricides, suggesting the several acaricides would be chosen for the control of those populations. However, the field-collected populations were exhibited a severe cross resistance with low susceptibility and high resistance allele frequency to almost tested acaricides, suggesting the current acaricides resistance levels are serious in rose cultivation area in Korea. The RCV and QS methods would be useful for the rapid and accurate collection of valuable information associated with acaricide resistance.

The high quality contact between graphene and the metal electrode is a crucial factor in achieving the high performance of graphene transistors. However, there is not sufficient research about contact resistance reduction methods to improve the junction of metal-graphene. In this paper, we propose a new method to decrease the contact resistance between graphene and metal using directly grown graphene over a metal surface. The study found that the grown graphene over copper, as an intermediate layer between the copper and the transferred graphene, reduces contact resistance, and that the adhesion strength between graphene and metal becomes stronger. The results confirmed the contact resistance of the metal-graphene of the proposed structure is nearly half that of the conventional contact structure.

The performance of graphene-based electronic devices is critically affected by the quality of the graphene-metal contact. The understanding of graphene-metal is therefore critical for the successful development of graphene-based electronic devices, especially field-effect-transistors. Here, we provide a review of the peculiar properties of graphene-metal contacts, including work function pinning, the charge transport mechanism, the impact of the process on the contract resistance, and other factors.

Two point mutations (V419L and L925I) in the voltage-sensitive sodium channel (VSSC) α-subunit gene have been identified in deltamethrin-resistant bedbugs. To predict resistance allele frequencies of sodium channel mutations (V419L and L925I) in bedbugs at a population level, we developed quantitative sequencing (QS) protocol. The signal ratios between resistant and susceptible nucleotides were generated from sequencing chromatogram and plotted against the corresponding resistance allele frequencies. Linear regression coefficients of the plots were close to 1 (r2 = 0.9928 and 0.9998), suggesting that the signal ratios are reliable correlated with the resistance allele frequencies. To enable on-site monitoring of pyrethroid resistance in bed bugs, residual contact vial (RCV) bioassay method was established and used to determine median lethal concentration (LC50) values to deltamethrin for various bed bug strains. Resistance allele frequencies in these bedbug strains predicted by QS were correlated well with the RCV bioassay results, confirming the roles of two mutations in pyrethroid resistance. Taken together, employment of QS in conjunction with RCV bioassay should greatly facilitate resistance monitoring of bedbugs in the field.

The stable fly, Stomoxys calcitrans L., is an important pest of livestock. Stable flies are considered as mechanical vectors of veterinary disease. Pyrethroids and organophosphates have been widely used for stable fly control. To establish resistance monitoring molecular tool, we isolated the partial cDNA and genomic fragments of voltage-sensitive sodium channel and acetylcholinesterase genes encompassing the well known conserved sites for resistance-associated mutations. To examine the current status of stable fly resistance to pyrethroids and organophosphates mediated by the nerve insensitivity mechanism in Korean population of S. calcitrans, DNA-based genotyping in conjunction with residual contact vial (RCV) bioassay were conducted with 11 representative regional field populations. No resistance-associated mutations were detected in these S. calcitrans populations, suggesting that these populations are likely still susceptible to both pyrethroids and organophosphates. Establishment of RCV bioassay protocol and availalbility of target site sequence information will greatly facilitate resistance monitoring of S. calcitrans in the field.

To establish a rapid diagnosis method for the monitoring of acaricide resistance in the two-spotted spider mite, Tetranychus urticae, we evaluated the performance of residual contact vial (RCV) method as a routine bioassay for T. urticae by using two widely used acaricides, abamectin and tebupenpyrad. Appropriate concentrations of test acaricides were dissolved in acetone and evenly coated (100 μl) onto the inside wall of a 4-ml glass vial using a rolling machine. The average survival times in untreated control vial was longer than 12 hrs in the absence of food or water regardless of cap being closed or open. Webbing behavior of mites inside the vial, which may interfere with maximum chemical contact, began to be observed from 8 hrs post treatment. The minimum concentrations causing 100% mortality within 8 hrs posttreatment in a susceptible strain of T. urticae were determined to be 30 and 60 ppm in abamectin and tebupenpyrad, respectively. Dose-response curve was significantly affected by temperature in both acaricides, in which the knockdown rate increased greatly as temperature increased. The endpoint mortality at 6-8 hrs posttreatment, however, was not significantly affected by temperature. Nymphal stage of mites showed more rapid intoxication response than adults but endpoint mortality at 6-8 hrs posttreatment was not substantially different between developmental stages. When compared with the results from conventional spray method, RCV method showed moderate to high correlation coefficients (r=0.51~0.98), suggesting that it is a reliable in determining susceptibility of T. urticae. The vial-coated pesticides were stable at least one year when stored at -20°C as determined by LC-MS/MS analysis. Moreover, there was no significant difference in the bioassay results in repeated experiments with three different persons, indicative of high reproducibility of RCV. The RCV diagnostic kit, when used by farmers on site, should provide crucial and essential information for the selection of most suitable acaricides for different field populations of T. urticae.

본 연구에서는 LCD패키지용 이방성 전도 필름의 전기적, 기계적 특성 및 신뢰성에 미치는 접속 변수의 영향을 연구하였다. 이방성 전도 필름을 통한 전기적 전도 현상을 각각의 도전 입자와 기판 사이의 기계적 접촉에 의해 접촉 방향으로만 전류가 흐르게 되는 것이 주되는 전도 기구이다. 따라서 접속 압력에 따라 각각의 도전 입자의 변형으로 기판 사이의 접촉 면적이 변하는데 이방성 전도필름의 접촉 저항은 이런 접촉 변화에 의해 결정된다. 접속 압력에 따라 초기에 접촉 저항은 감소하다가 점차 접촉 저항기가 안정화되는 거동을 보였다. 그러나 높은 접속 압력에서는 오히려 저항치가 약간 증가함을 보였다. 이방성 전도 필름 접속의 접착력을 평가하기 위해 필 테스트(peel test)를 시행하였는데, 접속 압력과 접속 온도를 증가 시킬수록 이방성 전도 필름 접속의 접착력을 평가하기 위해 고온 시효 시험, 온도 사이클링 시험, 고온 고습 시험의 신뢰성 시험을 시행하였으며, 이중 고온 고습 시험이 ACF접속의 전기적, 기계적 특성에 가장 악영향을 주었다. 또 큰 압력으로 접속된 것보다 작은 압력으로 접속되었을 때, 그리고 도전입자로는 금속 코팅 된 폴리머 입자가 사용될 때 신뢰성이 상대적으로 좋은 것을 발견했다.

본 연구에서는 다양한 RC 슬래브의 접촉 발파 실험을 수행하여 내폭 성능을 평가하였다. RC 슬래브의 내폭 성능 향상을 위해 섬유 보강과 외부 CFRP 시트 보강을 도입하였다. 폭발하중 실험은 2,000×1,000×100mm RC 슬래브를 제작하였고, 일반 콘크리트와 강섬유 보강 콘크리트, 하이브리드 PVA 섬유 보강 시멘트 복합체, 초고성능 콘크리트를 적용하였다. 접촉 발파로 생긴 RC 슬래브의 손상 정도를 크레틀, 스폴과 브리치의 직경과 깊이로 평가하였다. 실험 결과를 LS-DYNA 유한요소해석 프로그램과 Morishita 등의 예측식으로 검증하고 비교분석하였다. 분석 결과, LS-DYNA 프로그램을 이용하여 크레틀, 스폴, 브리치의 직경 및 깊이에 대한 개략적인 예측이 가능하며, 폭발하중 하에서 손상부의 거시적 거동을 모사함으로써 부재의 파괴 이력을 나타낼 수 있었다. 국부 손상에 대한 세가지 예측식이 소개되어 있으나 경험식으로써의 한계가 존재하며, 이에 대한 추가 연구가 필요하다고 판단된다.