Field Tests of Synthetic Sex Pheromone of the Apple Leafminer Moth, Phyllonorycter ringoniella

The apple leafminer moth, Phyllonorycter ringoniella, is becoming a more serious insect pest on apple trees with four to five generations a year in Korea. In order to devise a forecasting method for more accurate estimation of their numbers and development timing, the sex attractant was studied. Various ratios, from 10:0 to 0:10, of the two components, (Z)-10-tetradecenyl acetate (Z10–14:Ac) and (E,Z)-4,10-tetradecadienyl acetate (E4,Z10–14:Ac), identified from the sex pheromone gland (Jung and Boo, 1997), were tested for attractivity in terms of behavioral response (taxis, approach, and landing) against P. ringoniella males in a wind tunnel. The lure with Z10–14:Ac/E4,Z10–14:Ac in a ratio of 4:6 elicited the highest response in two (taxis and approach) measurement categories. For eliciting landing behavior, the two blends of 5:5 and 4:6 were best. The single component, Z10–14:Ac, elicited taxis behavior, but a combination of two chemicals was needed for eliciting all three behaviors. In the field, male attraction to various lure mixtures in Pherocon IC traps was usually greater than attraction to virgin females. The best field activity was in the lure baited with a 4:6 ratio of Z10–14:Ac and E4,Z10–14:Ac. Similar results were obtained from tests conducted in a net house. This optimum ratio for attracting P. ringoniella males in Korea is different from those reported in Japan (10:3) or China (7:3 to 6:4). The isomer E10–14:Ac neither improved nor depressed the number of catches when added at up to 10% of the total mixture to lures of the two components in the 4:6 ratio. The attractivity of the lures increased with higher amounts of the pheromones, up to 10 g in the wind-tunnel experiment and 5 mg in the apple orchard. The number of males captured was not significantly different among traps installed at 0.3, 1.5, or 2 m above the ground, or among wing, delta, or water traps. A rubber septum dispenser impregnated with 1 mg of the 4:6 mixture maintained its field attractivity for up to eight weeks.     

EVA／VC溶胀特性和EVA溶胀粉化研究

乙烯-醋酸乙烯酯/氯乙烯(EVA/VC)溶胀和EVA溶胀粉化研究结果表明,EVA/VC饱和溶胀临界点前,VC在EVA中的溶胀量随VC分压增加而增加;临界点后,VC分压保持不变,VC在EVA中达到饱和溶胀;65℃时,EVA溶胀粉化的VC与EVA配比应大于3.68,粉化温度、粉化时间、搅拌速率、分散剂和助溶胀剂浓度对粉化EVA的颗粒特性均有影响,通过实验得到优化的粉化条件。     

Physical properties of metal-doped zinc oxide films for surface acoustic wave application

Metal-doped ZnO [MZO] thin films show changes of the following properties by a dopant. First, group III element (Al, In, Ga)-doped ZnO thin films have a high conductivity having an n-type semiconductor characteristic. Second, group I element (Li, Na, K)-doped ZnO thin films have high resistivity due to a dopant that accepts a carrier. The metal-doped ZnO (M = Li, Ag) films were prepared by radio frequency magnetron sputtering on glass substrates with the MZO targets. We investigated on the optical and electrical properties of the as-sputtered MZO films as dependences on the doping contents in the targets. All the MZO films had shown a preferred orientation in the [002] direction. As the quantity and the variety of metal dopants were changed, the crystallinity and the transmittance, as well as optical band gap were changed. The electrical resistivity was also changed with changing metal doping amounts and kinds of dopants. An epitaxial Li-doped ZnO film has a high resistivity and very smooth surface; it will have the most optimum conditions which can be used for the piezoelectric devices.     

Polymer blend containing a thermotropic polyester with long flexible spacer in the main chain

Polymer blends of nylon 66 and thermotropic polyester with long flexible spacers in the main chains were prepared by melt mixing. The samples were made as single filaments by passing the polymer blend through a small and round die of a capillary rheometer. Mechanical properties of blends showed that the modulus and strength of nylon 66 could be improved without reduction of extensibility. The morphology of fractured surfaces was observed by a scanning electron microscope (SEM). It showed that the microfibrillar structure of a thermotropic polyester was formed by extensional flow while the spherical and ellipsoidal particles in the nylon 66 (matrix polymer) were produced by shear flow. The polyester particles were occasionally covered with adhering matrix polymer because of good adhesion between these two polymers. They were highly elongated by tensile stress without loss of elongational characteristics of blends. This fact was explained by very good adhesion between the two phases.     

Efficient photovoltaic effect in graphene/h-BN/silicon heterostructure self-powered photodetector

Graphene (Gr)/Si-based optoelectronic devices have attracted a lot of academic attention due to the simpler fabrication processes, low costs, and higher performance of their two-dimensional (2D)/three-dimensional (3D) hybrid interfaces in Schottky junction that promotes electron-hole separation. However, due to the built-in potential of Gr/Si as a photodetector, the I_ph /I_dark ratio is often hindered near zero-bias at relatively low illumination intensity. This is a major drawback in self-powered photodetectors. In this study, we have demonstrated a self-powered van der Waals heterostructure photodetector in the visible range using a Gr/hexagonal boron nitride (h-BN)/Si structure and clarified that the thin h-BN insertion can engineer asymmetric carrier transport and avoid interlayer coupling at the interface. The dark current was able to be suppressed by inserting an h-BN insulator layer, while maintaining the photocurrent with minimal decrease at near zero-bias. As a result, the normalized photocurrent-to-dark ratio (NPDR) is improved more than 10⁴ times. Also, both I_ph/I_dark ratio and detectivity, increase by more than 10⁴ times at −0.03 V drain voltage. The proposed Gr/h-BN/Si heterostructure is able to contribute to the introduction of next-generation photodetectors and photovoltaic devices based on graphene or silicon.

     

Shape optimization of two-dimensional thermal conducting solid using boundary integral equation formulation

A method for shape design sensitivity analysis of two-dimensional thermal conducting solid is presented using the material derivative concept and the adjoint variable method. A general thermal boundary condition with heat convection is considered in addition to prescribed temperature and heat flux. The method for deriving the sensitivity formula is based on standard direct boundary integral equation formulation. The sensitivity of a general functional depending on temperature and heat flux is considered. The method is then applied to obtain the sensitivity analysis is demonstrated by a hollow cylinder problem with exact solution. A weight minimization problem of a thermal diffuser is considered as a practical application. The sensitivity by the presented method is compared with that by finite differences and an optimal shape is found by use of an optimization routine.     

Axisymmetric thermoelastic shape sensitivity analysis and its application to turbine disc design

A general method for shape design sensiti vityi analysis (SDSA) as applied to an axisymmetric thermoelasticity problem is presented using the material derivative concept and the adjoint variable method. The sensitivity of a general functional composed of thermal and mechanical quantities is considered. The method for deriving the sensitivity formula is based on standard direct thermal and elastic boundary integral equation formulation. It is then applied to obtain explicit formulas for a representative displacement and stress constraint imposed on a sector of the boundary. Results of numerical implementation are presented for weight minimization of a turbine disc under thermomechanical loading. The sensitivities of the displacement and stress constraint calculated by the formulas are compared with those by finite differences. Optimum shape obtained under the thermomechanical loading is discussed with that under the mechanical loading only, clearly showing the practical importance of the SDSA of thermoelastic systems.     

Right stereoisomers for sex pheromone components of the apple leafminer,Lyonetia prunifoliella,in Korea

The sex pheromone of the American population of Lyonetia prunifoliella (Lepidoptera: Lyonetiidae) was reported to be composed of three components, 10,14-dimethyloctadec-1-ene (10me14me-1-ene-18Hy), 5,9-dimethyloctadecane (5me9me-18Hy), and 5,9-dimethylheptadecane (5me9me-17Hy). Studies with a Korean population showed that the 10S,14S isomer of the major compound was the major electrophysiologically by active stereoisomer. The 5S,9S isomers of the minar constituents also elicited electrophysiological responses. In field trappings, among the three components, the racemic mixture of 10me14me-1-ene-18Hy attracted L. prunifoliella males strongly, and the binary or tertiary combinations with racemic mixtures of the other two components did not increase trap catches. Among the four stereoisomers of 10me14me-1-ene-18Hy, only the 10S,14S isomer attracted L. prunifoliella males, as suggested by the EAG test, and attraction to the other three isomers was not observed. All stereoisomers of each minor component, as well as their racemic components, did not seem to have any additional effect on male attraction in Korea.     

Selective Deposition of Hafnium Oxide Nanothin Films on OTS Patterned Si(100) Substrates by Metal–Organic Chemical Vapor Deposition

Soft lithography is a method for the manufacture of micro/nano size patterns and structures by using organic materials without the use of high energy. In particular, microcontact printing (muCP) is a very convenient and nonphotolithographic technique that can generate patterned features of self-assembled monolayers (SAMs). In this study, we carried out the selective deposition of HfO₂ nano-thin films on Si(100) substrates by combination of muCP using octadecyltrichlorosilane (OTS) and metal-organic chemical vapor deposition (MOCVD). Single molecular precursor of Hf(O^tBu) ₄ was used for the growth of HfO₂ nano-films, and the deposition was carried out between 150degC and 400degC at a pressure of 3times10^-2 torr. The as-grown films were characterized by x-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive x-ray (EDX), x-ray photoelectron spectroscopy (XPS), and capacitance-voltage (C-V) and current-voltage (I-V) measurement. It is expected that the combination of muCP of SAM and MOCVD is a better method for fabricating the HfO ₂ thin films between micro and nano sizes     

An architecture of scalable ATM switching system and its performance

In this paper, we present the basic idea and some concepts for the architecture of the ATM switching system being developed in ETRI of KOREA, and also describe its performance. RSE (Reference Service Entity) concept is introduced to define the characteristics of user’s traffic. This concept is useful to represent the demand of CPE (Customer Premise Equipment) user sets and one of point‐to‐multipoint connections. We also propose RUCA (Reference Units for Connection Attempts) concept with which we can illustrate the call/connection level performance of the ATM switching system. This concept can be applied for measuring the call processing capability in both point‐to‐multipoint connections and multipoint‐to‐multipoint connections when call set‐up between users is performed by a sequence of point‐to‐point connections basis. From the basic concepts and the recommendations of ITU‐T, the design objective of the system performance is specified. We represent the methodologies for dimensioning the system to achieve the design objectives, and estimate the system performances. Then we show that our developing system has suitable performance to accommodate the future B‐ISDN. This revised version was published online in August 2006 with corrections to the Cover Date.