• Asian Pacific Journal of Cancer Prevention
• /
• 제14권6호
• /
• pp.3685-3688
• /
• 2013

Background: Clinicians determine degree of mammographic density based on tissue firmness on breast examination. The study aimed to compare breast density in mammography and clinical breast examination. Materials and Methods: Six-hundred sixty three women 40 years of age or older were studied. The breast exam density was graded from 1 to 4 by two expert surgeons and the mammographic parenchymal density by two expert radiologists. Then for practical reasons, grades 1 and 2 were considered as low-density and grades 3 and 4 as high-density. Results: High and low densities were detected in 84.5% and 15.5% of clinical breast examinations and 59.7% and 40.3% of mammographies, respectively. The statistical analysis showed a significant difference between the breast tissue densities in breast examination with those in mammography. Conclusions: A clinically dense breast does not necessarily imply a dense mammographic picture.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
• /
• pp.52-56
• /
• 2001

Experiments of 2 type on insulating compounds accomplished to change PVC using in URD(Underground) power cable jacketing. one was DB (Dielectric Breakdown) test on the pure base resins and the others were WVT(Water Vapor Transmission) test on the compounds which contained C/B(Carbon Black), anti-oxidant to base resin. a kind of specimens made by pressing to resin of pellet or lump form was HDPE(High Density Polyethylene), MDPE(Medium Density Polyehylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC (Polyvinyl Chloride). As a results of AC DB and WVT test, we saw that strength of Insulation was HDPE > LLDPE ≒ MDPE > LDPE and WVT ratio was HDPE < LLDPE < MDPE < LLDPE ≒ LDPE${\ll}$PVC. WVT of PVC using for jacket showed characteristic 15 times more than MDPE or LLDPE. Therefore, to development of watertightness cable, our works present need of Changing in insulating materials

• Ocean and Polar Research
• /
• 제42권4호
• /
• pp.271-281
• /
• 2020

We investigated mesozooplankton in the Yellow Sea in spring to understand its community structure and relationship with environmental factors. Total mesozooplankton density ranged from 1,542 to 7,367 ind. m-3 and the biomass ranged from 3 to 42 mg C m-3. The total density and biomass had a positive relationship with chlorophyll-a (chl-a) concentration. The mesozooplankton community was divided into two groups at 125.5 E by cluster analysis: one was an inshore group and the other was an offshore group. The inshore group of mesozooplankton was of high density but low diversity, while the offshore group was of high diversity but low density. Copepod Acartia hongi and its copepodites were the most abundant species, comprising 27.8% of the total mesozooplankton density. A. hongi was especially abundant at the inshore, serving as the indicator species of the inshore group. Redundancy analysis found a positive relationship between the density of A. hongi and chl-a concentration. Oithona similis and Centropages abdominalis were 2nd and 3rd dominant species comprising 9 and 7% of the total density, respectively. The density of O. similis was positively related to water depth, but C. abdominalis was related to chl-a concentration. Chl-a concentration seems to influence significantly the mesozooplankton community structure in the Yellow Sea in spring, rather than water temperature or salinity.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.201-201
• /
• 2017

Delayed stem senescence of soybean is a phenomenon of retarded leaf and stem yellowing, where plants maintain a high stem water content and remain chlorophyll in leaf and stem at maturity stage. This phenomenon was one of the most important physiological disease in Japanese soybean cultivation. The occurrence of delayed stem senescence was affected by sowing time. And the most of Japanese field, soybean seeds were sowed in June. June is the rainy season in Japan, and the soil water content of field become higher in this season. In this study, the effects of late sowing (July sowing) on the yield and the occurrence of delayed stem senescence in soybean cultivars Enrei, Tachinagaha and Ayakogane were examined from 2013 to 2015, in the experimental farm at Nihon University (Fujisawa-city, Kanagawa, Japan). The seeds of all cultivars were sowed in June (June-normal density plot) or July (July-normal density plot, July-high density plot and July-super high density plot) in field experiment. The pot experiments were carried out in 2014. In all cultivars, the yield of July-high density plot and July-super high density were higher than that of June normal density plot. And the yield of June-normal density plot was the same as that of July-normal density plot. In all cultivars, the occurrence of delayed stem senescence was increased by seeding in June sowing. And in July sowing plots, no significance difference in the occurrence of delayed stem senescence was observed among density plots. One of reason about the increasing the occurrence of delayed stem senescence in June-normal plot was the increasing of the damaged seeds by bean bugs. Add one of reason about the decreasing of the occurrence of delayed stem senescence of July plots was the decreasing of the amount of cytokinin supplied from root to top and water stress after the flowering time was improved compared with the June plot. In conclusion, the yield of Enrei, Tachinagaha and Ayakogane were not changed by changing the sowing time from June to July. In all cultivars, the occurrence of delayed stem senescence were decreasing by seeding in July.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문초록집
• /
• pp.377.2-377
• /
• 2002

In optical disk drives (ODD), the demands of high data density and high speed have been increasing rapidly to achieve high data capacity and data transfer rate The use of short wavelength laser and high track following performance are needed to raise data density and data rate. For high-performance actuator, the improvement of linearity and acceleration become more important. (omitted)

• 전기의세계
• /
• 제27권3호
• /
• pp.31-35
• /
• 1978

In this paper, in order to clarify the mature of traps in polymer, the thermally stimulated current (TSC) measurements were mad on high density polyethylene by changing the condition of the high-field treatment such as the strength of the field (Fe), the treatment time (te) and the heating rate (.betha.). In addition, the TSC measured from the HDPE was compared with that from LDPE having different crystallinity. The obtained results can suggest that the trapping proceeds during the high-field treatment and the trap associated with the peak P$_{2}$ may have the closed relation to drystallinity and the release of trapped charge is enhanced by the molecular motion.

• 동력기계공학회지
• /
• 제9권4호
• /
• pp.143-147
• /
• 2005

Graphites is well known to have superior advantages to high-temperature, high-pressured, and strong acid-state gas or liquid because it is very stable and chemical structure. Nowadays the new plant with high performance is developed in field of chemical industries, so the need of graphites is increasing rapidly. In this paper, newly developed graphite products with high density is investigated by the mechanical properties of that. I introduced the graphite material which developed for this experiment by the forming process in order to compare to the commercial graphite sheet from expanded graphite which made by the rolling process. Through measuring density and hardness test also tensile test, I investigated the characteristics of these materials. It is verified that the newly developed graphite products forming method is able to make graphite products which have superior mechanical properties than that of commercial graphite sheet.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.393-396
• /
• 2001

According to the development of power electronic element(GTO, IGBT) and material for electrical machines(permanent magnet, super conductor), the technology for electrical machines is nowaday rapidly developing. Here with, a novel electrical machine, based on the new conception of transverse flux configuration leads to a considerable Increase in power density and enables simultaneously high efficiency. The transverse flux machine with PM excitation will be applied to gearless direct drives for railway traction system and magnetic levitation system. The designed and measured performance of transverse machine for railway traction system and magnetic levitation system revealed a great potential of system improvements to reduce linear motor mass and increase efficiency.

• 대한건축학회논문집:구조계
• /
• 제34권1호
• /
• pp.69-78
• /
• 2018

The purpose of this study is propose eco-friendly remodeling while protecting the living environment of existing residents and preserving the living in pleasant by considering the characteristic of high density sloped residential area. And then, the optimum insulation condition is analyzed based on the energy efficiency, economic analysis and environmental effect. It will be possible as the basic information for remodeling of each housing in sloped area. The energy demanding, cost and the carbon emission reduction is analyzed with the residential area in Seo-gu, Busan by eco-remodelling.

• Bulletin of the Korean Chemical Society
• /
• 제33권2호
• /
• pp.564-570
• /
• 2012

s-Tetrazine is the essential candidate of many energetic compounds due to its high nitrogen content, enthalpy of formation and thermal stability. The present study explores the design of s-tetrazine derivatives in which different $-NO_2$, $-NH_2$ and $-N_3$ substituted azoles are attached to the tetrazine ring via C-N linkage. The density functional theory (DFT) is used to predict the geometries, heats of formation (HOFs) and other energetic properties. The predicted results show that azide group plays a very important role in increasing HOF values of the s-tetrazine derivatives. The densities for designed molecules were predicted by using the crystal packing calculations. The introduction of $-NO_2$ group improves the density as compared to $-N_3$, and $-NH_2$ groups and hence the detonation performance. Bond dissociation energy analysis and insensitivity correlations revealed that amino derivatives are better candidates considering insensitivity and stability.