• The Korean Journal of Zoology
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• v.12 no.3
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• pp.85-93
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• 1969

The frequencies of chromosomal aberrations, unmerical variations at various time intervals and DNA synthetic patterns after the treatment with steroids in synchronized human kidney cells treated with 5-AU were investigated in the present experiment. 1. In 5-AU treated group, the frequency of chromosomal aberrations per cell was 0.131, 3 times of control group. In 5-AU + progesterone and 5-AU + testosterone groups, the frequency of chromosomal aberrations per cell was 0.340 and 0.452 respectively. 2. In 5-AU treated group, the frequency of cells with abnormal chromosome number was 0.8%, which was distributed throughout the time regardless of time interval. In 5-AU + progesterone and 5-AU + testosterone groups, the frequencies of cells with abnormal chromosome number were 2.2% and 4.3% respectively and they increased with the time. In 5-AU + progesterone group, the frequency of chromosomal aberrations exhiited the peaks at 12 and 18 hour stage after the treatment with steroids and, in 5-AU + testosterone group, it decreased with the time and in 5-AU treated group no significant difference was observed 3. The increase of labeled metaphases and labelling intensities in 5-AU treated cells are the result of the accumulation of cells at S stage by 5-AU. The decrease of labeled metaphases, labelling intensities and the delay of DNA synthetic time were observed in steroid groups. DNA synthetic pattern of sex chromosomes differs according to the step of cell cycle and DNA synthetic time is irregular because of double treatments with 5-AU and steroids.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.2
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• pp.11-26
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• 1964

The studies reported herein are on the varietal differences of rice in the effects of seeding times and nursery periods on the components such as, culm length, ear length, number of ears, ear weight, straw weight, and grain/straw ratio following the first series of studies on heading date. In the present investigations, 50 rice varieties, as the preceding studies, were seeded nine times at the interval of 15 days from March 15 to July 28 in 1963. Each variety seeded at respective time was transplanted in 40 days in nursery after seeded. Reviewing the result obtained from the first series of the studies on heading date, the number of days required to heading from seeding were decreased by delaying the seeding time. Most varieties tended to decrease in the number of days from seeding to heading by the 8th planting time. Some of varieties seemed to be decreased in the number of days from seeding to heading by 9th seeding time. However most varieties were failed to show heading delaying the seeding date at the 10th seeding. The results on the effects of altering the seeding time on the components and varietal differences of the response are summarized as follows; 1) Culm length; It appeared that culm length was shortened when the number of days from seeding to heading was decreased by delaying the seeding date. The varieties which needed many days to heading were also shortened in their culm length. 2) Ear length; Ear length was also shortened when the number of days needed tocheading was decreased, by delaying the seeding time. The varieties which needed many days for heading were also shortened in their ear length, while those which headed earlier seemed to be lengthened in their ear lengths. 3) Number of ears; It was shown that the number of ears was increased with the delay of the heading date, whereas, at the 9th seeding the number of ears was decreased when delayed the heading date. 4) Ear weight; Ear weight per hill was also likely to be heavy throughout the seeding times and varieties except the 7th and 8th seedings in which it appeared to be light on the contrary. 5) Straw weight; Straw weight became heavier as delayed the seeding date throughout all the varieties and seeding dates. 6) The grain/straw ratio; The grain/straw ratio was gradually increased by the 5th seeding time, reaching the pick at 5th. An examination of the varieties at each seeding date showed that the grain/straw ratio was low from 1st to 3rd seeding and from 7th to 9th seeding, when the number of days required to heading from seeding are increased. At the 4th seeding time-which is standard seeding time-5th, and 6th seeding times the ratio was high with the delay of heading.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.4
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• pp.515-519
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• 1999

With the purpose of determining the influence of sexual partners on the oestrous behaviour and to evaluate the accuracy of predicting the time from implant withdrawal to sexual receptivity following a treatment with Synchromate B (SMB), 15 adult Brahman cows were used in each of three phases. During phase I and n, random pairs of animals were induced to display oestrus one pair after the other at daily intervals, while in phase III, cows were induced alternately, every other day, one cow on the 1st day, two on the 3rd, one on the 5th, two on the 7th until all cows were treated. Sixty six percent of the cows in phases I and II, and 80% in phase III came into oestrous after treatment. The interval between implant withdrawal and, expected and observed oestrous was statistically different in all phases. Clustering of oestrous was evident. Cows displayed sexual receptivity within a. range of -24 to +96; -24 to +72 and -216 to +192 hours after implant withdrawal for the three phases, respectively, with a tendency for cows treated first (within treatments), to delay their oestrus signs and vice versa. In phase III, four cows showed oestrous behaviour with the implant in place. These in spite of not observing pre-ovulatory follicles. Correlation values of 0.99, 0.93 and 0.90 (P<0.05) were found respectively among treatments, between the number of cows coming into oestrus and the number of mounts observed. These findings suggest that there are social and behavioural factors in a herd that may override exogenous synchronisation treatments.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.3
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• pp.1-7
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• 2002

This paper presents a new PLL clock generator that can improve a jitter noise characteristics and acquisition process by designing a multi-PFD(Phase Frequency Detector) and an adaptive charge pump circuit. The conventional PLL has not only a jitter noise caused from such a demerit of the wide dead zone and duty cycle, but also a long delay interval that makes a high speed operation unable. An advanced multi-structured PFD circuit using the TSPC(True Single Phase Clocking) circuit is proposed, in which it shows an excellent functionalities in terms of the jitter noises by designing its circuit with the exact dead zone and duty cycle. Our new designed adaptive charge pump in the loop filter of a PLL can improve an acquisition characteristic by adaptively increasing of current. The Hspice simulation is done to evaluate the performance of the proposed circuit. Simulation result shows that our PLL has under 0.01ns in the dead zone, no influence from the duty cycle of input signals and under 50ns in the acquisition time. This circuit will be able to be used in develops of high-performance microprocessors and digital systems.  

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.1
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• pp.118-123
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• 1987

In relation to the dust detonatians which have imposed severe damages on the industry, the ignitability of various dusts has been investigated on a horizontal shock tube in this study. By using a newly designed air injector, very well-distributed clouds could be obtained. The proper reflected shock conditions have been generated by placing a reflector 1.5cm behind the air injector, which reflected the incident shock wave. The incident shock waves in the range of Mach number 2.8-3.3 created the postreflected shock temperature of 1200-1600K. Experimentally the ignition delay was defined as the time interval between the arrival of a reflected shock wave at dusts and the detection of visible light. Measured ignition delays of dusts investigated were located lower than 1msec under the above conditions. These values are one-order higher than those in the incident shock wave condition. In this type of ignitiion process the following three processes are considered to play important roles; heating of a particle, generation of volatile gas by endothermic devolatilization process, and its diffusion from the particle surface and the formation of stoichiometric mixture with oxidizer.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.3
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• pp.455-469
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• 1994

Regular radiographic examination has been considered an essential diagnositic method for osseointegrated dental implantation. This study investigated marginal bone loss through the measurement on periapical radiographs and changes in bone density through digital subtraction image radiographic method around 88 endoseous root-form dental implants in 43 human subjects. Four types of endosseous dental implants were investigated : Standard series, Mini series and Hex-lock system of Steri-Oss Dental implant system, and $Br{\aa}nemark$-type implant from 3i dental implant system, in a 3 month interval for a total period of 12 months. The results were as follows : 1. Rapid bone loss occurred in the first 3 months in all 4 groups, and the bone level stabilized at the first thread of the implant fixtures. Amount of bone loss for 12 months showed correlation with the length of the polished neck portion. 2. Most of the implant systems showed resorption of alveolar bone up to the polished neck portion although a long polished neck could delay the resolution. 3. Alveolar bone loss apical to the polished neck portion stabilized at the first thread of the fixtures with no correlation to either the time of exposure of the polished neck or types of implant systems. 4. No changes in bone density around the implant threads were observed throughout the experimental period. Bone density decreased at the marginal bone, and increased at the newly-formed alveolar crest. These results indicate that most of the alveolar bone loss occur within the first 12 months after installation of endosseous root-form dental implants resulting in the exposure of polished neck portions, and the bone level stabilizes thereafter at the first thread portions of the implant fixtures. The experimental period of 12 months seems insufficient for observing changes in bone density, and a long-term observation should be needed.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.1
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• pp.20-26
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• 2005

Ultrasonic guided waves have been widely employed for long range inspection of structures such as plates, rods and pipes. There are numerous modes with different wave velocities, and the appropriate mode selection is one of key techniques in the application of guided waves. In the present work, phase tuning by an array transducer was applied to generate ultrasonic guided waves. For this purpose, 8-channel ultrasonic pulser/receiver and their controller which enables sequential activation of each channels with given time delay were developed. Eight transducers were fabricated in order to generate guided waves by using an array transducer. The selective tuning of wave mode can be achieved by changing the interval between elements of an array transducer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1685-1695
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• 2010

In this paper, we propose a new reliable multicast MAC protocol over the IEEE 802.11-based tactical ad hoc networks. The major contribution compared to the previous reliable multicast schemes using consecutive CTSs/ACKs is that the proposed scheme can send multiple CTS/ACK messages concurrently assisted by MC-DS/CDMA mechanisms. When multiple receivers receive the RTS/DATA message from a sender, they respond with the CTS/ACK message spread with pre-assigned code in the same time interval. The proposed scheme can reduce the overhead of multiple CTSs/ACKs. It is also possible to alleviate the received signal strength at the enemy detector and thus it improves low probability of detection performance. Through simulations and analysis, the proposed scheme outperforms that of the multiple CTSs/ACks in terms of the throughput, transmission delay and low probability of detection.

• The KIPS Transactions:PartD
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• v.11D no.5
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• pp.1159-1166
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• 2004

This paper describes a multimedia synchronization model based on the MPEG-4(Moving Picture Expert Group) system. It defines and modifies new nodes for representing temporal relationships between media objects in the BIFS(Binary Format for Scene) of MPEG-4 system which Integrates, manages and transfers multimedia objects such as audio, video, image, etc. The relationships are represented by using a multimedia temporal model during the start, play and delay time interval. In addition, we illustrate a multimedia authoring system that includes the Interface used for defining the temporal relationships. Differently from several contentional tools generally appropriate for professional users who can edit the BIFS nodes of themselves, the system provides end-users with the function that can define the temporal relationships of multimedia objects directly in the interface.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.42-52
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• 2017

This was a study on the ultimate effect and characteristics of introducing a roundabout through a review of literature on the subject of roundabout. In order to examine an effect produced when roundabout is substituted for ordinary signal-controlled intersection operated at Daego Five-way Intersection and Seongmo Five-way Intersection located in Junggu, Daejeon Metropolitan City, site to be studied, the produced effect was analyzed through comparison between before and after introducing roundabouts in series at Daego Five-way Intersection and Seongmo Five-way Intersection by using microscopic traffic simulation program VISSIM widely used for analyzing an effect of roundabout based on a survey of geometric structure, traffic volume and signal interval on the site. As mentioned above, when Daego Five-way Intersection and Seongmo Five-way Intersection was changed to roundabout, a positive effect was produced on average speed and delay time in comparison with the existing status. It is possible to expect that roundabout can be more efficiently operated when 2 places on the site are changed to double roundabout than when separately changed to roundabouts.