• 제목/요약/키워드: R&D3.0

Search Result 4,781, Processing Time 0.038 seconds

Socioeconomic Factors Relating to Obesity and Inadequate Nutrient Intake in Women in Low Income Families Residing in Seoul (서울지역 저소득층 여성의 비만 및 영양소 섭취 부족과 관련된 사회경제적 요인)

  • Hwang, Ji-Yun;Ru, Sung-Yeap;Ryu, Han-Kyoung;Park, Hee-Jung;Kim, Wha-Young
    • Journal of Nutrition and Health
    • /
    • v.42 no.2
    • /
    • pp.171-182
    • /
    • 2009
  • This study was performed to investigate socioeconomic factors relating to obesity and inadequate nutrient intake in women in low income families residing in Seoul. The subjects were 125 women (aged 41-87 y) recruited from the local health center for free health examination for low income families. The socioeconomic status such as educational level, income level, and housing condition were poor. For subjects aged less than 65 years, the prevalence of obesity was 44% based on BMI (${\geq}\;25\;kg/m^2$), 48% based on WHR (${\geq}\;0.85$), and 50% based on waist circumference (${\geq}\;80\;cm$) and for those more than 65 years, these were greater and 57%, 81%, and 79%, respectively. The main food sources of daily diet were vegetables, grains, and fruits. Energy and other nutrient intake was not adequate for all subjects and the inadequacy was more profound in the elderly, showing percentages of subjects whose intake was less than EAR were greater than 50% for all nutrients except for iron and below RI were also greater than 50% for all nutrients. The prevalence of obesity and nutrient inadequacy were not associated with socioeconomic status in subjects aged less than 65 years, however, obesity was associated with household income and nutrient inadequacy was related to education (vitamin A) and housing status (protein, phosphate, and iron) in the elderly. After adjustment for ages, in the elderly, OR for obesity (BMI ${\geq}$ 25, OR = 12.601; 95% CI = 2.338-67.911) and central obesity (WC ${\geq}$ 80 cm, OR = 4.778; 95% CI = 1.103-20.696) were greater in subjects who earned less than 500 thousand Won per month than who earned more. For inadequate nutrient intake, the OR for inadequate intake of Vitamin A (OR = 4.555; 95% CI = 1.491-13.914) was greater in subjects with no education than those educated. Subjects without her own house had greater risk for inadequate intake for protein (OR = 3.660; 95% CI = 1.118-11.981), phosphate (OR = 3.428; 95% CI = 1.157-10.158), and iron (OR = 3.765; 95% CI = 1.205-11.766) than subjects possessing her house. In elderly females in low income families, the socioeconomic status was associated with the risk for obesity (income level) and inadequate nutrient intake (education level and housing status). More attention on these groups should be given for prevention of obesity and inadequate nutrient intake.

Study of Selective Etching of GaAs over AlGaAs and InGaP Semiconductors in High Density Planar Inductively Coupled BCl3/SF6 Plasmas (고밀도 평판형 유도결합 BCl3/SF6 플라즈마를 이용한 GaAs/AlGaAs와 InGaP 반도체의 선택적 식각에 관한 연구)

  • Yoo Seungryul;Ryu Hyunwoo;Lim Wantae;Lee Jewon;Cho Guan Sik;Jeon Minhyon;Song Hanjung;Lee BongJu;Ko Jong Soo;Go Jeung Sang;Pearton S. J.
    • Korean Journal of Materials Research
    • /
    • v.15 no.3
    • /
    • pp.161-165
    • /
    • 2005
  • We investigated selective dry etching of GaAs over AlGaAs and InGaP in high density planar inductively coupled $BCl_3/SF_6$ plasmas. The process parameters were ICP source power (0-500 W), RE chuck power (0-30W) and gas composition $(60-100\%\;BCl_3\;in\;BCl_3/SF_6)$. The process results were characterized in terms of etch rate, selectivities of GaAs over AlGaAs and InGaP, surface morphology, surface roughness and residues after etching. $BCl_3/SF_6$ selective etching of GaAs showed quite good results in this study. Selectivities of GaAs $(GaAs:AlGaAs\~36:1,\;GaAs:InGaP\~45:1)$ were superior at $18BCl_3/2SF_6$, 20 W RF chuck power, 300 W ICP source power and 7.5 mTorr. Addition of $(5-15\%)SF_6\;to\;BCl_3$ produced relatively high selectivities of GaAs over AlGaAs and InGaP during etching due to decrease of etch rates of AlGaAs and InGaP (boiling points of etch products: $AlF_3\~1300^{\circ}C,\;InF_3>1200^{\circ}C$ at atmosphere) at the condition. SEM and AFM data showed slightly sloped sidewall and somewhat rough surface$(RMS\~9nm)$. XPS study on the surface of processed GaAs proved a very clean surface after dry etching. It shows that planar inductively coupled $BCl_3/SF_6$ plasmas could be a good candidate for selective dry etching of GaAs over AlGaAs and InGaP.

A study of compaction ratio and permeability of soil with different water content (축제용흙의 함수비 변화에 의한 다짐율 및 수용계수 변화에 관한 연구)

  • 윤충섭
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.13 no.4
    • /
    • pp.2456-2470
    • /
    • 1971
  • Compaction of soil is very important for construction of soil structures such as highway fills, embankment of reservoir and seadike. With increasing compaction effort, the strength of soil, interor friction and Cohesion increas greatly while the reduction of permerbilityis evident. Factors which may influence compaction effort are moisture content, grain size, grain distribution and other physical properties as well as the variable method of compaction. The moisture content among these parameter is the most important thing. For making the maximum density to a given soil, the comparable optimum water content is required. If there is a slight change in water content when compared with optimum water content, the compaction ratio will decrease and the corresponding mechanical properties will change evidently. The results in this study of soil compaction with different water content are summarized as follows. 1) The maximum dry density increased and corresponding optimum moisture content decreased with increasing of coarse grain size and the compaction curve is steeper than increasing of fine grain size. 2) The maximum dry density is decreased with increasing of the optimum water content and a relationship both parameter becomes rdam-max=2.232-0.02785 $W_0$ But this relstionship will be change to $r_d=ae^{-bw}$ when comparable water content changes. 3) In case of most soils, a dry condition is better than wet condition to give a compactive effort, but the latter condition is only preferable when the liquid limit of soil exceeds 50 percent. 4) The compaction ratio of cohesive soil is greeter than cohesionless soil even the amount of coarse grain sizes are same. 5) The relationship between the maximum dry density and porosity is as rdmax=2,186-0.872e, but it changes to $r_d=ae^{be}$ when water content vary from optimum water content. 6) The void ratio is increased with increasing of optimum water content as n=15.85+1.075 w, but therelation becames $n=ae^{bw}$ if there is a variation in water content. 7) The increament of permeabilty is high when the soil is a high plasticity or coarse. 8) The coefficient of permeability of soil compacted in wet condition is lower than the soil compacted in dry condition. 9) Cohesive soil has higher permeability than cohesionless soil even the amount of coarse particles are same. 10) In generall, the soil which has high optimum water content has lower coefficient of permeability than low optimum water content. 11) The coefficient of permeability has a certain relations with density, gradation and void ratio and it increase with increasing of saturation degree.

  • PDF

A STATISTICAL ANALYSIS OF SOLAR WIND DYNAMIC PRESSURE PULSES DURING GEOMAGNETIC STORMS (지자기폭풍 기간 동안의 태양풍 동압력 펄스에 관한 통계적 분석)

  • Baek, J.H.;Lee, D.Y.;Kim, K.C.;Choi, C.R.;Moon, Y.J.;Cho, K.S.;Park, Y.D.
    • Journal of Astronomy and Space Sciences
    • /
    • v.22 no.4
    • /
    • pp.419-430
    • /
    • 2005
  • We have carried out a statistical analysis on solar wind dynamic pressure pulses during geomagnetic storms. The Dst index was used to identify 111 geomagnetic storms that occurred in the time interval from 1997 through 2001. We have selected only the events having the minimum Dst value less than -50 nT. In order to identify the pressure impact precisely, we have used the horizontal component data of the magnetic field H (northward) at low latitudes as well as the solar wind pressure data themselves. Our analysis leads to the following results: (1) The enhancement of H due to a pressure pulse tends to be proportional to the magnitude of minimum Dst value; (2) The occurrence frequency of pressure pulses also increases with storm intensity. (3) For about $30\%$ of our storms, the occurrence frequency of pressure pulses is greater than $0.4\#/hr$, implying that to. those storms the pressure pulses occur more frequently than do periodic substorms with an average substorm duration of 2.5 hrs. In order to understand the origin of these pressure pulses, we have first examined responsible storm drivers. It turns out that $65\%$ of the studied storms we driven by coronal mass ejections (CMEs) while others are associated with corotating interaction regions $(6.3\%)$ or Type II bursts $(7.2\%)$. Out of the storms that are driven by CMEs, over $70\%$ show that the main phase interval overlaps with the sheath, namely, the region between CME body and the shock, and with the leading region of a CME. This suggests that the origin of the frequent pressure pulses is often due to density fluctuations in the sheath region and the leading edge of the CME body.

A Study on the Compatibility of Korean Temperature Guidelines for Stockpile Material Environmental Test (저장물자 환경시험을 위한 한국적 온도기준 적합성 연구)

  • Lee, Il Ro;Byun, Kisik;Cho, Sung-Yong;Kim, Kyung Pil;Park, Jae Woo
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.21 no.8
    • /
    • pp.187-194
    • /
    • 2020
  • The T&E (Test and Evaluation) results were applied for a judgment basis to decide the developmental process of system engineering for efficient weapon system R&D (Research and Development). During the OT&E (Operational Test and Evaluation) and DT&E (Development Test and Evaluation), an environmental test is essential for weapon system development owing to their highly exposed operational conditions. Based on the MIL-STD-810, MIL-HDBK-310, and AECTP 200, the ROK armed forces recommended operating temperatures for the ROK weapon system and applied this to the DT&E and OT&E. This study examined the compatibility of Korean temperature guidelines for stockpile material considering recent climate change. Moreover, this study analyzed the data from hourly measured temperatures on 101 observatories during 60 years, from 1960 to 2020, and percentage (0.5%, 1%, 5%, and 10%) and the 𝜎 (3𝜎, 2𝜎, and 1𝜎) frequency of occurrence on rigorous hot (August) and cold (January) periods, respectively. The results indicate that the highest temperature was 41℃, and the 0.5% frequency of occurrence was 37.0℃. In the case of the cold period, the lowest temperature was -32.6℃ and the 0.5% frequency of occurrence was -21.1℃. By considering the previously recommended operating temperature range for a general ground system, -30 ~ 40℃, regional operation probability is recognized 99.999%. Despite the recent abnormal climate change from global warming, the Korean temperature guidelines are compatible with the stockpile material environmental test.

Quality Evaluation of Juanbyeo as Aseptic-packaged Cooked Rice (무균포장밥 가공 적합품종 주안벼의 식미특성)

  • Oh, Sea-Kwan;Kim, Dae-Jung;Cheun, A-Reum;Yoon, Mi-Ra;Hong, Ha-Cheol;Choi, Im-Soo;Oh, Yea-Jin;Oh, Ki-Back;Kim, Yeon-Kyu
    • Korean Journal of Food Science and Technology
    • /
    • v.42 no.6
    • /
    • pp.721-726
    • /
    • 2010
  • The objective of this study was to evaluate several varieties of aseptic-packaged cooked rice including Juanbyeo. Quality evaluations, such as by amylose, setback, toyo values and amylograms, were significantly higher in the Juanbyeo as compared to other samples. In addition, the Juanbyeo aseptic-packeged cooked rice showed significantly higher palatability characteristics and had a greater water absorption ratio than the other samples. For cold cooked rice, the relationship between palatability and texture was significantly high (p<0.01). Ilpumbyeo showed high scores for taste as a hot cooked rice, but as a cold cooked rice taste scores were lower than other samples. In the case of Juanbyeo cold cooked rice flavor was improved. When the Juanbyeo aseptic-packaged cooked rice was reheated in a microwave oven, it had better palatability than other varieties. Thus, the results of this study suggested that Juanbyeo can be effectively utilized as aseptic-packaged cooked rice.

A Study on the Current Status of Prescribed Drugs in Oriental Health Insurance and their Improvement (한방건강보험 약제 투약 실태 및 활성화 방안 연구)

  • Kwon, Yong-Chan;Yoo, Wang-Keun;Seo, Bu-Il
    • The Korea Journal of Herbology
    • /
    • v.27 no.2
    • /
    • pp.1-16
    • /
    • 2012
  • Objective : To investigate the current status of prescription drugs in Oriental medical institutes and to draw up a future plan for the revitalization of Oriental medical health insurance, this survey has been performed. Method : The survey has been made with 321 doctors working at Oriental medical institutes in Daegu and Kyungbuk areas for a period of 3 month from June 1, 2010 until September 1, 2010. Result : 1. When it comes to the current status of the use of herbal drugs in Oriental Health insurance, most of doctors surveyed prescribe insurance drugs, and they prescribe insurance drugs to patients, who are less than 20% of total patients visiting their clinics. 2. The awareness of Herbal Health Care Drugs is investigated. When it comes to the understanding of the difference between insurance drugs(powder type drugs) and granular type drugs, doctors admit that they differ only in one aspect, whether or not their being covered by health insurance. Based on the survey results on the understanding of insurance coverage of granular type drugs, doctors, even though they long for granular type drugs to be accepted as insurance drugs, are worrying whether the number of outpatients might dwindle due to increased insurance co-payments. They also point out that the biggest obstacles in the expansion of the granular type drugs as insurance drugs are the lack of understanding of the government and the objection of the Health Insurance Review and Assesment service (HIRA) for fear of increased insurance claims. 3. Upon investigation on Oriental medicine doctors' understandings of herbal pharmaceutical industry, it is found that doctors' responses on pharmaceutical industry are not all positive ones('new product development and neglect of R&D infrastructure' and 'smallness of industry'). When it is investigated what area needs the greatest improvement in herbal pharmaceutical industry, 'securing sufficient capital, good manufacturing, and strengthening quality control', is the highest. 4. When it is asked what are the most needed in order to improve herbal health insurance medicine, responses such as 'the increase in the accessibility to and the utilization of Oriental medical clinics through the diversification of the means of prescriptions', 'the improvement of insurance benefits(cap adjustments)', 'increase the proportion of high quality medicinal plants', 'the ceiling of co-payments(deductible) at 20,000 won or more', 'expansion of the choices of formulations', 'formulational expansions of tablets and pills', and finally 'admittance and expansion of granular type drug as insurance drug' are the highest. 5. Upon investigating the general characteristics of the current status of the usage of Oriental health care herbal drugs, the followings are observed. First, the frequency of use of health insurance drugs by the doctors who use health insurance with general characteristics shows similar differences in case of total monthly sales amount (p<0.001), average number of daily patients (p<0.05). Secondly, as to the willingness of the expanded usage of insurance drugs, similar differences are observed in case of total monthly sales amount (p<0.05). 6. Upon investigating the general characteristics of the perception of Herbal health care drugs, the followings are observed. First, inspecting general characteristics and insurance claims due to increased co-payments(deductible amount) reveals similar differences in case of working period (p<0.01) and in case of total monthly sales amount (p <0.01). Secondly, inspecting general characteristics and the obstacles that hinder granular type drugs from being accepted as health care insurance drugs shows similar differences in case of working period (p<0.05). 7. Upon investigating the general characteristics of the understanding of Oriental Herbal pharmaceutical companies, the followings are observed. First, opinions on the general characteristics of pharmaceutical companies, when examined with variance analysis, shows similar differences in case of total monthly sales amount (p<0.05). Secondly, when opinions are examined on general characteristics and the problems of herbal pharmaceutical companies, similar differences are found in case of working period (p<0.01) and in case of total monthly sales amount (p<0.001). Lastly, opinions on the general characteristics and reforms of pharmaceutical companies, similar differences are observed in case of working period (p<0.001). 8. Upon investigating the general characteristics of the improvement of insurance Herbal drugs, the followings are observed. First, regarding general characteristics and insurance benefits, similar differences are observed in case of working period (p<0.05), in case of total monthly sales amount (p<0.05), and in case of average number of daily patients (p<0.01). Secondly, opinions on the general characteristics and the needs for the improvement of Herbal insurance drugs are examined in 5 different aspects, which are the approval of granular type drugs as insurance drugs, the expanded practices of the number of prescription insurance drugs, the needs of a variety of formulations, the needs of TFT of which numbers of Oriental medical doctors are members for the revision of the existing system, and the needs of adjusting the current ceiling of the fixed amount and the fixed rate. When processed by the analysis of variance, the results show similar differences in case of average number of daily patients (p<0.01). Conclusion : From the results of this study the first measures to take are, to reform overall insurance benefit system, including insurance co-payment system(fixed rate cap adjustment), to expand the number of the herbal drugs to be prescribed matching with insurance benefit accordingly, and to revitalize herbal medicine insurance system through the change of various formulations. In addition, it is recommended to improve the effectiveness of herbal medicine by making plans to enhance the efficacy of herbal medicine and by enabling small pharmaceutical companies to outgrow themselves.

Studies on the Biochemical Features of Soybean Seeds for Higher Protein Variety -With Emphasis on Accumulation during Maturation and Electrophoretic Patterns of Proteins- (고단백 대두 품종 육성을 위한 종실의 생화학적 특성에 관한 연구 -단백질의 축적과 전기영동 유형을 중심으로)

  • Jong-Suk Lee
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.22 no.1
    • /
    • pp.135-166
    • /
    • 1977
  • Some biochemical features of varietal variation in seed protein and their implications for soybean breeding for high protein were pursued employing 86 soybean varieties of Korea, Japan, and the U.S.A. origins. Also, studied comparatively was the temporal pattern of protein components accumulation during seed development characteristic to the high protein variety. Seed protein content of the 86 soybean varieties varied 34.4 to 50.6%. Non-existence of variety having high content of both protein and oil, or high protein content with average oil content as well as high negative correlation between the content of protein and oil (r=-0.73$^{**}$) indicate strongly a great difficulty to breed high protein variety while conserving oil content. The total content of essential amino acids varied 32.82 to 36.63% and the total content of sulfur-containing amino acids varied 2.09 to 2.73% as tested for 12 varieties differing protein content from 40.0 to 50.6%. The content of methionine was positively correlated with the content of glutamic acid, which was the major amino acid (18.5%) in seed protein of soybean. In particular, the varieties Bongeui and Saikai #20 had high protein content as well as high content of sulfur-containing amino acids. The content of lysine was negatively correlated with that of isoleucine, but positively correlated with protein content. The content of alanine, valine or leucine was correlated positively with oil content. The seed protein of soybean was built with 12 to 16 components depending on variety as revealed on disc acrylamide gel electrophoresis. The 86 varieties were classified into 11 groups of characteristic electrophoretic pattern. The protein component of Rm=0.14(b) showed the greatest varietal variation among the components in their relative contents, and negative correlation with the content of the other components, while the protein component of Rm=0.06(a) had a significant, positive correlation with protein content. There was sequential phases of rapid decrease, slow increase and stay in the protein content during seed development. Shorter period and lower rate of decrease followed by longer period and higher rate of increase in protein content during seed development was of characteristic to high protein variety together with earlier and continuous development at higher rate of the protein component a. Considering the extremely low methionine content of the protein component a, breeding for high protein content may result in lower quality of soybean protein.n.

  • PDF

Polymorphisms in Glutamate Receptor, Ionotropic, N-methyl-D-aspartate 2B(GRIN2B) Genes of Autism Spectrum Disorders in Korean Population : Family-based Association Study (한국인 자폐스펙트럼장애에서 Glutamate Receptor, Ionotropic, N-methyl-D-Aspartate 2B(GRIN2B) 유전자 다형성-가족기반연구)

  • Yoo, Hee Jeong;Cho, In Hee;Park, Mira;Yoo, Hanik K.;Kim, Jin Hee;Kim, Soon Ae
    • Korean Journal of Biological Psychiatry
    • /
    • v.13 no.4
    • /
    • pp.289-298
    • /
    • 2006
  • Objectives : Autism is a complex neurodevelopmental spectrum disorder with a strong genetic component. Previous neurochemical and genetic studies suggested the possible involvement of glutamate N-methyl-D-aspartate(NMDA) receptor in autism. The aim of study was to investigate the association between the NMDA2B receptor gene(GRIN2B) and autism spectrum disorders(ASD) in the Korean population. Methods : The patients with ASD were diagnosed with Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule based on DSM-IV diagnostic classification. The present study was conducted with the detection of four single nucleotide polymorphisms(SNPs) in GRIK2 and family-based association analysis of the single nucleotide polymorphisms in Korean ASD trios using transmission disequilibrium test (TDT). Results : One hundred twenty six patients with ASD and their biological parents were analyzed. 86.5% were male and 85.1% were diagnosed as autistic disorder. The mean age was $71.9{\pm}31.6$ months(range : 26-185 months). We found that rs1805247 showed significantly preferential transmission(TDT ${\chi}^2$=12.8, p<0.001) in ASD. Conclusion : One SNP in GRIN2B gene was significantly associated with ASD in the Korean population. This result suggests the possible involvement of glutamate NMDA receptor gene in the development of ASD.

  • PDF

Recent research activities on hybrid rocket in Japan

  • Harunori, Nagata
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2011.04a
    • /
    • pp.1-2
    • /
    • 2011
  • Hybrid rockets have lately attracted attention as a strong candidate of small, low cost, safe and reliable launch vehicles. A significant topic is that the first commercially sponsored space ship, SpaceShipOne vehicle chose a hybrid rocket. The main factors for the choice were safety of operation, system cost, quick turnaround, and thrust termination. In Japan, five universities including Hokkaido University and three private companies organized "Hybrid Rocket Research Group" from 1998 to 2002. Their main purpose was to downsize the cost and scale of rocket experiments. In 2002, UNISEC (University Space Engineering Consortium) and HASTIC (Hokkaido Aerospace Science and Technology Incubation Center) took over the educational and R&D rocket activities respectively and the research group dissolved. In 2008, JAXA/ISAS and eleven universities formed "Hybrid Rocket Research Working Group" as a subcommittee of the Steering Committee for Space Engineering in ISAS. Their goal is to demonstrate technical feasibility of lowcost and high frequency launches of nano/micro satellites into sun-synchronous orbits. Hybrid rockets use a combination of solid and liquid propellants. Usually the fuel is in a solid phase. A serious problem of hybrid rockets is the low regression rate of the solid fuel. In single port hybrids the low regression rate below 1 mm/s causes large L/D exceeding a hundred and small fuel loading ratio falling below 0.3. Multi-port hybrids are a typical solution to solve this problem. However, this solution is not the mainstream in Japan. Another approach is to use high regression rate fuels. For example, a fuel regression rate of 4 mm/s decreases L/D to around 10 and increases the loading ratio to around 0.75. Liquefying fuels such as paraffins are strong candidates for high regression fuels and subject of active research in Japan too. Nakagawa et al. in Tokai University employed EVA (Ethylene Vinyl Acetate) to modify viscosity of paraffin based fuels and investigated the effect of viscosity on regression rates. Wada et al. in Akita University employed LTP (Low melting ThermoPlastic) as another candidate of liquefying fuels and demonstrated high regression rates comparable to paraffin fuels. Hori et al. in JAXA/ISAS employed glycidylazide-poly(ethylene glycol) (GAP-PEG) copolymers as high regression rate fuels and modified the combustion characteristics by changing the PEG mixing ratio. Regression rate improvement by changing internal ballistics is another stream of research. The author proposed a new fuel configuration named "CAMUI" in 1998. CAMUI comes from an abbreviation of "cascaded multistage impinging-jet" meaning the distinctive flow field. A CAMUI type fuel grain consists of several cylindrical fuel blocks with two ports in axial direction. The port alignment shifts 90 degrees with each other to make jets out of ports impinge on the upstream end face of the downstream fuel block, resulting in intense heat transfer to the fuel. Yuasa et al. in Tokyo Metropolitan University employed swirling injection method and improved regression rates more than three times higher. However, regression rate distribution along the axis is not uniform due to the decay of the swirl strength. Aso et al. in Kyushu University employed multi-swirl injection to solve this problem. Combinations of swirling injection and paraffin based fuel have been tried and some results show very high regression rates exceeding ten times of conventional one. High fuel regression rates by new fuel, new internal ballistics, or combination of them require faster fuel-oxidizer mixing to maintain combustion efficiency. Nakagawa et al. succeeded to improve combustion efficiency of a paraffin-based fuel from 77% to 96% by a baffle plate. Another effective approach some researchers are trying is to use an aft-chamber to increase residence time. Better understanding of the new flow fields is necessary to reveal basic mechanisms of regression enhancement. Yuasa et al. visualized the combustion field in a swirling injection type motor. Nakagawa et al. observed boundary layer combustion of wax-based fuels. To understand detailed flow structures in swirling flow type hybrids, Sawada et al. (Tohoku Univ.), Teramoto et al. (Univ. of Tokyo), Shimada et al. (ISAS), and Tsuboi et al. (Kyushu Inst. Tech.) are trying to simulate the flow field numerically. Main challenges are turbulent reaction, stiffness due to low Mach number flow, fuel regression model, and other non-steady phenomena. Oshima et al. in Hokkaido University simulated CAMUI type flow fields and discussed correspondence relation between regression distribution of a burning surface and the vortex structure over the surface.

  • PDF