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A Study on the Performance Improvement of Diesel Automobile Engine with Ultrasonic Fuel Feeding System(II)-On the Spray Characteristics and Engine Performance- (초음파 연료분사장치용 디젤자동차의 성능향상에 관한 연구(II)-분무특성과 기관성능에 대하여-)

  • Yang, J.K.;Jung, J.D.;Ryu, J. I.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.6
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    • pp.50-56
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    • 1994
  • This is an experimental study on the performance characteristics of Diesel Automobile with ultrasonic fuel feeding system. For this purpose, ultrasonic fuel feeding system was made and atomization characteristics was measured. Base on this result, carried out engine dynamometer test to investigate the performance characteristics of diesel automobile with ultrasonic fuel feeding system in comparison with conventional diesel fuel injector. The results are as follows. 1) In the spray characteristics test, fuel particle sizes were decreased about 11%~21%. 2) In engine dynamometer test, -The power was increased about 5%~11%. -The thermal efficiency was improved about 6%~11%. -The specific fuel consumption was improved about 6%~19%. -The smoke concentration was decreased about 11%~50%.

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Effects of Laser Welding Speed on the Tensile and Forming Characteristics of Tailored Blanks (레이저 용접 속도가 테일러드 블랭크의 인장 특성 및 성형성에 미치는 영향)

  • 표창률
    • Journal of the Korean Society of Safety
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    • v.15 no.3
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    • pp.7-13
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    • 2000
  • Forming characteristics of tailored blank are mostly effected by the welding method. Recently, laser welding is widely used for the tailored blank. However, tensile and forming characteristics vary due to welding conditions such as welding speed, heat flux etc. The objective of this paper is to evaluate the effect of welding speed on the tensile and forming characteristics of laser welded tailored blank. For this purpose, tailored blank specimens with different welding speed were prepared and tensile tests were performed. Also forming tests such as LDH and OSU test, were performed to evaluate the effect of welding speed on the forming characteristics. Finally, forming limit diagrams were obtained for different welding speed.

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Taxonomic Characteristics of Six Species of Entomopathogenic Fungi Isolated from the Silkworm, Bombyx mori

  • Nguyen, Mau Tuan;Nam, Sung Hee;Park, Hyun Ro;Han, Myung Sae
    • International Journal of Industrial Entomology and Biomaterials
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    • v.9 no.2
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    • pp.229-234
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    • 2004
  • Six entomopathogenic fungus isolates, Beauveria bassiana J57A, Nomuraea rileyi J125A, Paecilomyces farinosus J3A, Paecilomyces fumosoroseus J50A, Metarhizium anisopliae J88, Aspergilius sp. J64A, causing muscardine disease and aspergillosis in the silkworm, Bombyx mori were investigated for their cultural and morphological characteristics (on PDA culture media within 14 days at $24^{\circ}C$). The results showed that they differ each other from the features of cultural characteristics (colony elevation, colony color, colony growth rate) or morphological characteristics (conidiogenous cell structure, phialides, conidia size and shape). Among cultural characteristics, colony color is the easiest recognizable character between isolates. The morphological characteristics of each fungal isolate correspond to the descriptions of current system of classification.

Numerical Analysis Unsteady Flow Characteristics of the Wells Turbine (웰즈터빈의 비정상유동특성에 관한 수치해석)

  • 김태훈;박일규;이연원
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2001.05a
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    • pp.69-74
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    • 2001
  • The Wells turbine has hysteresis characteristics in a reciprocating flow. In this paper, in order to understand unsteady flow characteristics of the Wells turbine, a sinusoidal flow condition is simulated. The flow conditions and hysteresis characteristics, including blade thickness, are investigated over a period of time. The pressure distributions along the blade surface are investigated at mid-span to clarify the cause of the hysteresis. The result has shown that the hysteresis characteristics become more pronounced as blade thickness becomes larger. The occurrence of these characteristics depends on the varying behavior of wakes between an accelerating flow and a develerating flow.

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Thermo-elastoplastic characteristics of heat-resisting functionally graded composite structures

  • Cho, Jin-Rae;Ha, Dae-Yul
    • Structural Engineering and Mechanics
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    • v.11 no.1
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    • pp.49-70
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    • 2001
  • This paper is concerned with a study on thermo-elastoplastic characteristics of functionally graded composite. Compared to the classical layered composites, it shows a wide range of thermo-elastoplastic characteristics according to the choice of two major parameters, the thickness-wise volume fraction of constituents and the relative thickness ratio of the graded layer. Therefore, by selecting an appropriate combination of the two parameters, one is expected to design the most suitable heat-resisting composite for a given thermal circumstance. Here, we address the parametric investigation on its characteristics together with theoretical study on thermo-elastoplasticity and numerical techniques for its finite element approximations. Through the numerical experiments, we examine the influence of two parameters on the thermo-elastoplastic characteristics.

Retrieval Method using Device Characteristics and Device Usage Characteristics in Multi-Device Environment (다중 기기 환경에서 기기 특성과 기기 사용 특성을 활용한 검색 기법)

  • Kwon, Joon Hee
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.17 no.3
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    • pp.17-26
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    • 2021
  • Internet of Things is an infrastructure of the interconnected devices. In Internet of Things environment, many smart devices are used in daily life. It requires a new retrieval method using multiple devices. We propose an information retrieval method using both device characteristics and device usage characteristics in multi-device environments. Firstly, information retrieval is performed using a general purpose device. And then, it is performed using dedicated devices. Our method uses both characteristics of the devices and usage characteristics of them. Moreover, it considers queries on the general purpose device. This paper proposes a new retrieval method and describes algorithms. Then, it presents smart home scenarios. Performance evaluation is performed using the scenarios. The evaluation results show higher precision and efficiency than previous researches. The proposed method gets information more accurately and quickly in IOT multiple device environments.

Factors influencing positive subjective health awareness in multicultural adolescents in South Korea: Data from the multicultural adolescents panel study

  • Choi, Sun Yeob
    • Child Health Nursing Research
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    • v.27 no.4
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    • pp.328-338
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    • 2021
  • Purpose: This study aimed to identify the factors influencing positive subjective health awareness of middle school-age multicultural adolescents in Korea. Methods: This study used data from the fourth to sixth waves of the Multicultural Adolescents Panel Study conducted by the National Youth Policy Institute. In this study, a panel logit model analysis was performed using the Eviews 8.0 program (p<.050). Results: Socioeconomic status (r=.02, t=2.13, p=.033), body satisfaction (r=.71, t=1.97, p=.048), and depression (r=-.74, t=2.35, p=.018) influenced positive subjective health awareness in multicultural adolescents. When multicultural characteristics were entered into a statistical model with environmental and personal characteristics, multicultural characteristics did not have a significant influence on positive subjective health awareness. Conclusion: Environmental, personal, and multicultural characteristics were related to positive subjective health awareness in multicultural adolescents; thus, an integrated approach considering those variables is recommended. Nursing interventions and educational programs are needed to improve the psychological status of multicultural adolescents and reduce prejudice about them. In addition, nurses need to be sensitive to multicultural characteristics and the developmental characteristics of multicultural adolescents.

Study on the influence of hold-down spring on the vibration characteristics of core barrel

  • Tiancai Tan;Lei Sun;Litao Liu;Jie Yang
    • Nuclear Engineering and Technology
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    • v.55 no.9
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    • pp.3252-3259
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    • 2023
  • The influence of hold-down spring (HDS) on the vibration characteristics of core barrel is studied in this paper. First, the vibration characteristics experiment of core barrel was carried out with four type of different hold-down spring. These hold-down springs represent the same hold-down force under different spring stiffness and different hold-down force under the same spring stiffness. And then a new finite element method for researching the influence of hold-down spring on the vibration characteristics of core barrel was presented. This new method could consider the influence of the hold-down force and the spring stiffness at the same time. The results suggest that, the hold-down force and friction have greater influence on the vibration characteristics of core barrel than the spring stiffness, and the influence is nonlinear. The influence of the boundary condition on beam mode is greater than that on shell mode for core barrel.

Considering Read and Write Characteristics of Page Access Separately for Efficient Memory Management

  • Hyokyung Bahn
    • International journal of advanced smart convergence
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    • v.12 no.1
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    • pp.70-75
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    • 2023
  • With the recent proliferation of memory-intensive workloads such as deep learning, analyzing memory access characteristics for efficient memory management is becoming increasingly important. Since read and write operations in memory access have different characteristics, an efficient memory management policy should take into accountthe characteristics of thesetwo operationsseparately. Although some previous studies have considered the different characteristics of reads and writes, they require a modified hardware architecture supporting read bits and write bits. Unlike previous approaches, we propose a software-based management policy under the existing memory architecture for considering read/write characteristics. The proposed policy logically partitions memory space into the read/write area and the write area by making use of reference bits and dirty bits provided in modern paging systems. Simulation experiments with memory access traces show that our approach performs better than the CLOCK algorithm by 23% on average, and the effect is similar to the previous policy with hardware support.

Family Phenomena and Characteristics by Social-economic Charateristics of the Family (가족의 사회경제적 특성에 따른 가족현상 및 가족특성)

  • Kim, Young-Im;Kim, Hee-Girl;Park, Jin-Kyung;Jung, Hye-Sun
    • Research in Community and Public Health Nursing
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    • v.14 no.2
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    • pp.263-273
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    • 2003
  • Objectives: The purpose of this study was to identify the family phenomenon and characteristics by ICNP such as family shape, life standard. area, and development stage. Method: 1. Sample size was 115. 2. Data analysis method included frequency analysis including ratio. Results: 1. On the distribution of the family phenomena by family shape, the nuclear family showed a higher ratio on the distribution in family communication and the unhealthy life style. The nuclear family was related to children andhad a higher ratio on the inadequate care management of the sick member. The extended family showed the highest ratio on the inadequate care management of sick member. 2. On the distribution of the family phenomena by family life standard, the family with medium life standard showed a higher ratio on the inappropriate family coping, whereas the family with lower life standard appeared to have a higher ratio on the inadequate care management of the sick member. 3. On the distribution of the family phenomena by area. the large city area showed the highest ratio on the inappropriate family coping, the medium and small city area appeared to have the highest ratio on the unhealthy life style. The county area showed the highest ratio on the inadequate care management of sick member. 4. On the distribution of the family phenomena by development stage, the family in rearing period showed a higher ratio on the inappropriate family coping and the lack of family intimacy. Families with preschool children showed a higher ratio on the unhealthy life style, and families with school age children showed the highest ratio on the inappropriate family coping. Families with adolescents appeared to have the highest ratio on the disturbance in family communication, and families with launching young adults showed the highest ratio on the inadequate care management of sick member. 5. On the distribution of the family characteristics by family shape, the nuclear family showed a higher ratio on the family characteristics such as less communication chances among family members and neglect of general child rearing, whereas the third generation family appeared to have a higher ratio on the characteristics such as overburden of housewife's role and short of caring among family members. 6. On the distribution of the family characteristics by family life standard, the family of medium life standard showed higher ratio on the family characteristics such as a few communication chance among family and overburden of housewife's role, and the family of lower life standard appeared to higher ratio on the family characteristics such as short of caring among family members. 7. On the distribution of the family characteristics by area. the large city area showed a higher ratio on the family characteristics such as overburden of housewife's role and neglect of general child rearing. The medium and small city area appeared to have a higher ratio on the family characteristics such as less communication chancec among family members. The county area showed a higher ratio on the family characteristics such as short-term care among family members. 8. On the distribution of the family characteristics by development stage, the family with rearing period showed a higher ratio on the family characteristics such as neglect of general child rearing. Families with preschool children showed a higher ratio on the family characteristics such as less communication chancec among family members. Families with school age children showed a higher ratio on the family characteristics such as overburden of housewife's role. Families with adolescents appeared to have a higher ratio on the family characteristics such as less communication chances among family members. Families with launching young adults showed a higher ratio on the family characteristics such as less communication chances and short-term care among family members.

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