• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.1
• /
• pp.11-19
• /
• 2008

This paper proposes small VCM(voice coil motor) type, auto-focusing and zoom actuators for mobile information devices. In order to meet the large output displacement within small height restriction, the proposed auto-focusing actuator adopts curved suspensions, which are similar to a leaf-spring type suspension of optical disk drives. The sensitivity of design parameters on output displacement and dynamic performance is implemented using ANSYS (3D FEM tool) to determine the optimal geometry and stiffness of the curved suspensions. This paper also investigates a new zoom actuator without a suspension supporting a bobbin. The zoom actuator uses a moving rail and a stoper mechanism by generating rotational force at lens holder. Magnetic flux density of the zoom actuator are calculated by both the FEM and permeance method. Experiments using prototypes of the proposed focusing and zoom models show that both actuators meet the required displacement and performance.

• Horticultural Science & Technology
• /
• v.31 no.1
• /
• pp.38-49
• /
• 2013

Prohexadione-calcium (Pro-Ca), ethephon and transient water stress were evaluated in a factorial design, as potential inhibitors of early-season shoot growth of high density orchard management of apple (Malus domestica Borkh.) trees. In the experiment, water stress was imposed to one-half of the 7-year-old 'Golden Delicious'/M.9 apple trees in each of 5 blocks, by stopping irrigation for 3 weeks between 35 and 56 days after full bloom (AFB). Within each whole unit, the following Pro-Ca and ethephon treatments were randomly allocated at $2{\times}2$ factorial: a) 0 or 250 $mg{\cdot}L^{-1}$ a.i. Pro-Ca applied at 28 days AFB and b) 0 or 300 $mg{\cdot}L^{-1}$ a.i. ethephon applied twice (35 and 71 days AFB). All trees were hand thinned to king flowers prior to treatments. Vegetative shoot growth was markedly reduced by Pro-Ca, with its effect being obvious within 14 days after application, while ethephon and water stress treatments were less effective. Pro-Ca had no effect on fruit set and yield but slightly increased fruit size. Ethephon substantially reduced the fruit size and yield but had no effect on fruit set. Water stress reduced fruit set, fruit size and yield. With regard to fruit quality, Pro-Ca did not influence fruit shape, flesh firmness and soluble solids contents (SSC) but slightly reduced titratable acidity. Ethephon had no effect on fruit shape but increased firmness, SSC and acidity, while water stress did not influence these fruit quality attributes. Dry weight of dormant spur buds was reduced by both Pro-Ca and water stress, while increased by ethephon. The larger dormant buds led to the larger spur flowers at the tight cluster stage the following spring. Return flowering was promoted only by ethephon, especially on previous season's shoots. There were no significant interactions between Pro-Ca and ethephon or water stress on most variables observed in this study.

• Journal of the Semiconductor & Display Technology
• /
• v.20 no.4
• /
• pp.171-176
• /
• 2021

Die-to-wafer (D2W) hybrid bonding in the multilayer semiconductor manufacturing process is one of wafer direct bonding, and various studies are being conducted around the world. A noteworthy point in the current die-to-wafer process is that a lot of voids occur on the bonding surface of the die during bonding. In this study, as a suggested method for removing voids generated during the D2W hybrid bonding process, a flexible mechanism for implementing convex for die bonding to be applied to the bond head is proposed. In addition, modeling of flexible mechanisms, analysis/design/control/evaluation of static/dynamics properties are performed. The proposed system was controlled by capacitive sensor (lion precision, CPL 290), piezo actuator (P-888,91), and dSpace. This flexure mechanism implemented a working range of 200 ㎛, resolution(3σ) of 7.276nm, Inposition(3σ) of 3.503nm, settling time(2%) of 500.133ms by applying a reverse bridge type mechanism and leaf spring guide, and at the same time realized a maximum step difference of 6 ㎛ between die edge and center. The results of this study are applied to the D2W hybrid bonding process and are expected to bring about an effect of increasing semiconductor yield through void removal. In addition, it is expected that it can be utilized as a system that meets the convex variable amount required for each device by adjusting the elongation amount of the piezo actuator coupled to the flexible mechanism in a precise unit.

• Journal of Korean Society of Forest Science
• /
• v.77 no.3
• /
• pp.259-268
• /
• 1988

For the purpose of examining the effects of simulated acid rain on nutrient contents of plant tissues in Pintos densiflora seedlings and Forsythia koreana rooted cuttings, the experimental design of randomized block arrangement with three replications was implemented in the experimental field of Yesan National Agricultural Junior College. One-year-old Pinus densiflora seedlings and Forsythia koreana cuttings were planted in the pots filled the mixed soils(nursery soil : forest soil of siliceous sandy loam=1 : 1 v/v) in the early spring of 1986. The regime of artificial acid rain, in terms of spray frequency per month and spray amount at single treatment per plot, was simulated on the basis of climatological data averaged from 30 years records. Simulated acid rain(pH 2.0, pH 4.0, and pH 5.5 as control) containing sulfuric and nutric acid in the ratio of 3 : 2(chemical equivalant basis) diluted with ground water were treated on the experimental plants under condition of cutting off the natural precipitation with vinyl tunnel, during the growing season(May 1 to August 31) in 1986. The results obtained in this study were as follow : (1) As for the nitrogen contents in plant tissues, P. densiflora increased significantly in one-year-old stembranch and root tissues, and F. koreana increased significantly in leaf and root tissues, as the pH levels of acid rain decreased. (2) The available phosphate contents in root tissues of P. densiflora, and in leaf and root tissues of F. koreana were significantly decreased, as the pH levels of acid rain decreased. (3) $K_2O$, CaO and MgO contents in plant tissues were significantly decreased in the both species as the pH levels decreased. And the effects of acid rain on F. koreana were higher than those of P. densiflora. (4) Sulfur contents of plant tissues in the both species were increased at pH 2.0 treatment. There were significant differences among three acid rain treatments in leaf and root tissues of P. densiflora, and in all parts of F. koreana. (5) In the effects of simulated acid rain on the both species and the tested soils, in general, F. koreana revealed higher sensitiveness than P. densiflora, and the lower pH levels of simulated acid rain were treated, the more sharp reaction was showed.

• Korean Journal of Optics and Photonics
• /
• v.22 no.1
• /
• pp.46-52
• /
• 2011

A confocal microscope was developed utilizing a scanning sample stage based on a home-built double-compound flexure guide. A scanning sample stage with nano-scale resolution consisted of a double leaf spring based flexure, a displacement amplifying lever, a Piezo-electric Transducer(PZT) actuator and capacitance sensors. The performance of the two-axis stage was analyzed using a commercial finite element method program prior to the implementation. A single line laser was employed as the light source along with the Photo Multiplier Tube(PMT) that served as the detector. The performance of the developed confocal microscope was evaluated with a mouse ear skin imaging test. The designed scanning stage enabled us to build the confocal microscope without the two optical scanning mirror modules that are essential in the conventional laser scanning confocal microscope. The elimination of the scanning mirror modules makes the optical design of the confocal microscope simpler and more compact than the conventional system.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.9 no.1
• /
• pp.7-14
• /
• 1989

This experiment was carried out to determine the seasonal herbage production and utilization during the growing season of pasture on the forest (shading 30%). Plant height, leaf area index(LAl), dry matter(DM) production and distribution, chemical composition, in vitro dry matter digestibility(IVDMD), herbage utilization percentage and chewing efficiency were investigated using the Corridale sheep. Experimental field was treated by one plot design(3 rep.) and performed from 1987 to 1988 at Chungnam National University, Daejon. The results obtained are summarized as follows: 1. The highest plant height and LA1 were observed in May(35.0 cm, 4.89), followed by April(28.0 cm, 4.23), while the plant height and LA1 in October (13.0 cm, 0.49) showed very low. 2. During the growing season, about 58.3 % of annual DM production (7240 kg/ha) was produced during the spring (April, May and June) and the highest DM production was obtained in May (2040 kg/ha), which was more than 28.2 % of total DM production. However, DM production in July and August was about 24.2 % and those in September and October (17.5 %) was very low, but the difference of DM production from June to September was small. 3. The maximum DM production per day (65.8 kg/ha) was observed in May, followed by June (28.7 kglha), while DM production per day in October (16.5 kg/ha) showed very low (p <0.01). 4. Crude protein content and IVDMD of herbage samples during the spring (April, May and June) were higher, while crude fiber, ADF, and NDF content were lower in an summer growth herbage samples (July and August), but autumn growth herbage samples was intermediate. Crude ash content and IVDMD of collected herbage samples were slightly more, while crude fiber, ADF and NDF content were slightly less than offered and residued herbage samples during the growing season. 5. The maximum DM intake per metabolic body size was observed in May(68.9 g), followed by October (66.7 g), while very low in August (52.5 g). Significant positive correlation (p <0.05) was found between DM intake and IVDMD. 6. Herbage utilization percentage was very high in April (83.4 %), while very low in August (64.0 %). The percentage of annual herbage utilization was about 75.5 %. 7. The maximum ruminating and chewing efficiency of herbage samples were observed in May, followed by October, while very low in August.