• 한국가시화정보학회지
• /
• 제22권1호
• /
• pp.34-39
• /
• 2024

With the fine particulate matter (PM) poses a serious threat to public health and the environment. The ultrafine PM in particular can cause serious problems. This study investigates the effectiveness of a submicron dry fog system in removing fine PM. Two methods are used to create fine dust particles: burning incense and utilizing an aerosol generator. Results indicate that the dry fog system effectively removes fine dust particles, with a removal efficiency of up to 81.9% for PM₁₀ and 61.9% for PM_2.5 after 30 minutes of operation. The dry fog, characterized by a mean size of approximately 1.5 ㎛, exhibits superior performance in comparison to traditional water spraying methods, attributed to reduced water consumption and increased contact probability between water droplets and dust particles. Furthermore, experiments with uniform-sized particles which sizes are 1 ㎛ and 2 ㎛ demonstrate the system's capability in removing ultrafine PM. The proposed submicron dry fog system shows promise for mitigating fine dust pollution in various industrial settings, offering advantages such as energy consumption and enhanced safety for workers and equipment.

• Journal of Pharmaceutical Investigation
• /
• 제37권4호
• /
• pp.217-222
• /
• 2007

To develop cleansing tissue composed of silicone multiple emulsions which could easily remove make-up residues and confer skin protecting effect without damaging skin, we formulated various silicone multiple emulsions and evaluated the physicochemical properties including viscosity, cleansing effect, and safety effect. Also, cleansing tissue incorporated with silicone multiple (W/Si/W) emulsion was stored for 6 months, and judged its stability through microscopes under accelerated and long-term condition. Cleansing effect was evaluated by chromameter. Skin hydration effect was determined by corneometer and incorporation effect into non-woven fabric cotton was evaluated by volunteer survey. Low viscosity ranged from 400 centipoise (cP) to 1,000 cP was obtained from a stabilized W/Si/W emulsion containing more than 10% volatile silicone. Mean diameter of fresh W/Si/W emulsion was $20{\mu}m$, but after storage for 3 months at $45^{\circ}C$, the particle size of the W/Si/W emulsion increased up to $50{\mu}m$. Both W/Si/W emulsion-incorporated cleansing tissue and commercial product showed equally good cleansing effect. In addition, skin allergies such as erythema, edema, scaling itching, stinging, burning, tightness and prickling were not observed through macroscopic examination. From the transepidermal water loss results, the cleansing tissue consisting of W/Si/W emulsion showed superior hydration effect to commercial product. In conclusion, this study suggests cleansing tissue using W/Si/W emulsion could be used for an excellent efficacy compared with commercialized cleansing tissue.

• 대한치과기공학회지
• /
• 제25권1호
• /
• pp.29-40
• /
• 2003

This study was aimed to verify a comparison by dental alloys upon the marginal fitness of dental prosthesis. Firstly, we waxed up on 45 epoxy resin dies, pressed the margin with hands, and identified the marginal fitness with microscope. And we made a single direct spruing system type of sprue by 3 dental alloys - metal crown alloys, PFM crown alloys, and gold crown alloys - each 15, total 45 waxing up, adjusting W/P ratio and invested the cast ring. Then, we made the dental prosthesis using the electric casting machine. In these processes we followed the manufacturer's instructions, in order to maintain the other conditions from the inner and outer, which included investment and burning out. After we tried on the dental prosthesis on epoxy resin dies, we have got the means of marginal gap at 9 points with same distances, around the cervical line which was checked already, using microscope($\times$300). The results of this study were as follows : 1. Metal crown alloys showed 2.9% better in marginal fitness than PFM crown alloys, and the difference was not statistically significant(P=0.497). 2. Gold crown alloys showed 31.3% better in marginal fitness than Metal crown alloys, and the difference was statistically significant(P=0.004). 3. Gold crown alloys showed 32.4% better in marginal fitness than PFM crown alloys, and the difference was statistically significant(P=0.002). 4. We saw that Gold crown alloys was the best dental alloys in the marginal fitness among the three.(P=0.049).

• 대한치과기공학회지
• /
• 제42권3호
• /
• pp.213-219
• /
• 2020

Purpose: This study aimed to identify the impact of physical surface roughing with a polishing tool onto the pre-sintering yttria-stabilized tetragonal zirconia polycrystals (TZP) core and liner treatment for chemical bonding on the bond strength of TZP core and veneering ceramic. Methods: Overall, 80 specimens were classified into two groups (non-liner, NL; and usingliner, UL ) depending on the use of liner, and these two groups were then subclassified into four groups depending on the polishing tool used. (1) Non-liner groups: NS, non-liner+stone point; NC, non-liner+carbide bur; NP, non-liner+paper cone point; NT, non-liner+silicon point. (2) Using-liner groups: US, using-liner+stone point; UC, using-liner+carbide bur; UP, usingliner+paper cone point; UT, using-liner+silicon point. The pre-sintering surface roughing values and shapes were observed, and after burning up the veneering ceramic, the shear bond strength was measured using a universal testing machine. For significance testing, a one-way analysis of variance and Tukey's multiple comparison test were conducted. An optical microscope was used to observe the fracture plane, and the following results were obtained. Results: Surface roughness NP (4.09±0.51 ㎛) represented a higher value than other groups (p<0.001). In shear bond strength, NS (35.21±1.44 MPa) of the NL group showed the highest bond strength (p<0.001). The UL group did not show a statistically significant difference between groups (p=0.612). Conclusion: Our study findings reveal that the bond strength of TZP core and veneering ceramic was improved by pre-sintering physical surface treatment than by chemical bonding with liner surface treatment.

• 한국산림과학회지
• /
• 제78권4호
• /
• pp.419-424
• /
• 1989

내화제간(耐火劑間)의 상대적(相對的)인 내화효과(耐火效果)를 비교(比較), 검토(檢討)하여 보기 위하여 메란티(meranti) 합판(合板)에 5종(種)의 내화제(耐火劑)와 수처리(水處理)를 하고 열판건조(熱板乾燥)시킨 다음, ASTM D 2863-77의 산소지수법(酸素指數法)에 의거하여 Up and Down법(法)을 통하여 각각의 산소지수(酸素指數)를 구하였다. 시험결과(試驗結果)에 의하면 황산(黃酸)암모늄이 28.4, 제(第)1인산(燐酸)암모늄이 26.7, 제(第)2인산(燐酸)암모늄이 43.4, 붕사(硼砂)-붕산(硼酸)이 30.1, 미날리스가 32.4, 그리고 수처리(水處理)가 25.5의 산소지수(酸素指數)를 나타냈는데, 연소성(燃燒性)이 큰 물질(物質)일수록 낮은 산소지수(散素指數)를 지닌다는 사실(事實)로 미루어 볼 때 내화제간(耐火劑間)의 내화효과(耐火效果)는 제(第)2인산(燐酸)암모늄, 미날리스, 붕사(硼砂)-붕산(硼酸), 황산(黃酸)암모늄, 제(第)1인산(燐酸)암모늄의 순(順)으로 크다는 것을 구명할 수 있었다.

• 한국대기환경학회지
• /
• 제31권3호
• /
• pp.239-254
• /
• 2015

Little information on HUmic-Like Substances (HULIS) in ambient particulate matter has been reported yet in Korea. HULIS makes up a significant fraction of the water-soluble organic mass in the atmospheric aerosols and influence their water uptake properties. In this study 24-hr $PM_{2.5}$ samples were collected between December 2013 and October 2014 at an urban site in Gwangju and analyzed for organic carbon (OC), elemental carbon (EC), water-soluble OC (WSOC), HULIS, and ionic species, to investigate possible sources and formation processes of HULIS. HULIS was separated using solid phase extraction method and quantified by total organic carbon analyzer. During the study period, HULIS concentration ranged from 0.19 to $5.65{\mu}gC/m^3$ with an average of $1.83{\pm}1.22{\mu}gC/m^3$, accounting for on average 45% of the WSOC (12~ 73%), with higher in cold season than in warm season. Strong correlation of WSOC with HULIS ($R^2=0.91$) indicates their similar chemical characteristics. On the basis of the relationships between HULIS and a variety of chemical species (EC, $K^+$, $NO_3{^-}$, $SO_4{^{2-}}$, and oxalate), it was postulated that HULIS observed during summer and winter were likely attributed to secondary formation and primary emissions from biomass burning (BB) and traffics. Stronger correlation of HULIS with $K^+$, which is a BB tracer, in winter ($R^2=0.81$) than in summer ($R^2=0.66$), suggests more significant contribution of BB emissions in winter to the observed HULIS. It is interesting to note that BB emissions may also have an influence on the HULIS in summer, but further study using levoglucosan that is a unique organic marker of BB emissions is required during summer. Higher correlation between HULIS and oxalate, which is mainly formed through cloud processing and/or photochemical oxidation processes, was found in the summer ($R^2=0.76$) than in the winter ($R^2=0.63$), reflecting a high fraction of secondary organic aerosol in the summer.

• 대한한의학원전학회지
• /
• 제20권2호
• /
• pp.175-193
• /
• 2007

A theory of the school which attach great importance to moxibustion therapy was more developed from 'Ge Hong(葛洪)', 'Wang Tao(王燾)' up to "BianQueXinShu(扁鵲心書)" of 'Dou Cai(竇材)' in Song Dynasty. The first volume of "BianQueXinShu" was described about the principles of health preserving method, diagnosis, treatment related with meridian system, support Yang theory, moxibustion therapy over the 10 chapters and in the continued 3 chapters, explained the symptoms and related moxibustion therapies. The summary is as follows. The Yang energy is the essence of the human body and it is minutely explained in "Hwangdineijing(黃帝內經)". However, the younger scholars after 'Zhang Zhongjing(張仲景)' held different views with "Hwangdineijing" so they didn't control serious diseases. Supporting the Yang energy, it will be possible to human body in good health and long life and perennial youth and longevity. To do like this, the first important thing is a moxibustion, the second is a Taoist hermit medication(丹藥) and the third is well usage of Radix Aconiti Lateralis Preparata. According to the sequence of Yang energy deficiency, the stages of diseases are classified as Ordinary Gi(平氣), Latter deficient state(微虛), The more deficient state(甚虛), Exhausting state(將脫), Exhausted state(已脫) and in the consideration of each stage, it is used gradually with warm-natured berbs, warm-acrid herbs, warm-heated herbs and moxibustion therapy. If it comes to the stage of Exhausted state, the Yang energy is too weak to treat a disease. Therefore it is easy to harm human body with usage the treatment of the Purgationist school theory or the Cold and cool medical school theory, so it is needed a great attention to use these therapies. To summarized the keynote of 'Du Jae''s moxibustion therapy, the one is a minority of selection of points(1$^{\sim}$2 acupuncture points), the second is a majority of moxibustion units(50$^{\sim}$500 units), and the other is a focused selection of points on spleen and kidney(especially Gwanwon, CC4). And in this book, it was explained concretely about the size of moxibustion, according to the experiment with mentioned size, the burning time of moxibustion was almost 4 min 40 sec, so the big size moxibustion was one of the characteristic of moxibustion therapy revealed in this book. Also it was used 'Suseongsan(睡聖散)' - a kind of analgesic herb complexes - to reduce a pain during the usage of moxibustion therapy in this book. To develop the moxibustion theory, it is more investigated in the future that there wasn't significant relation between Gwanwon(CC4) and spleen and kidney meridian in theory, compared to many used Gwanwon(CC4) in the prescription, where as mentioned the importance of spleen and kidney in treatment, that considering the burning time(1 unit - 4 min 40 sec, 12 units an hour, maximum 288 units a day) there were no guidances about meals, sleeping, stool and urine, and that there was no concrete study about the toxicity of 'Suseongsan' as analgesic moxibustion therapy.

• Journal of Oral Medicine and Pain
• /
• 제32권1호
• /
• pp.57-67
• /
• 2007

현대인들에게는 다양한 증상과 징후를 나타내는 스트레스성 질환이 증가되고 있는 추세에 있다. 이러한 스트레스 시에 구강 내에는 구강건조이나 구강작열감증후군, 구강점막질환, 구취 등이 호발 된다는 것은 이미 널리 알려진 사실이다. 이때 대부분의 환자에서 공통적으로 나타나는 현상은 타액선의 기능적 및 구조적 변화에 따른 타액성분의 변화이다. 이에 저자는 스트레스가 구강 내 타액선에 어떠한 영향을 미치며, 타액선으로부터 분비되는 ${\alpha}$-amylase에 어떠한 영향을 미치는지를 알아보고자 본 실험을 시행한 결과 다음과 같은 유의성 있는 결과를 얻었다. 1. 구속 스트레스에 의하여 타액선 조직은 선포세포가 공포화되며 변성되었고, 선포간극이 이개되었으며, 도관주위조직도 변성되었다. 2. 구속 3시간 후에는 선포세포가 위축되기 시작하였고, 구속 6시간 후에는 선포 간 이개현상이 관찰되었으며, 구속 72시간 후에는 도관 주위 조직도 변성되기 시작하였고, 점차 심화되어 구속 168시간 후에는 선포와 도관 주위조직이 모두 심하게 변성되었다. 3. 면역조직화학적 검사에서 구속 3시간 후에는 amylase의 발현이 부분적으로 불규칙하게 관찰되었으며, 구속 6시간 후에는 다소 감소되었고, 구속 12시간 후에는 amylase가 부분적으로 응집되었으며, 점차 감소되고 응집되어, 구속 48시간 후에는 전 타액선에 amylase의 응집현상이 심화되었고, 구속 168시간 후에는 amylase의 발현이 매우 감소되었다. 이상의 결과를 바탕으로 정서적인 스트레스를 받으면 타액선이 변성될 수 있으며, 타액선으로부터 분비되는 중요한 소화 효소인 amylase가 변화되어 소화 장애를 일으키거나 구강건강과 관계없이 구취발생에도 영향을 미칠 수 있다고 예측할 수 있어, 향후 amylase의 분비변화에 따른 지속적인 연구가 필요할 것으로 생각된다.

• 한국가스학회지
• /
• 제24권4호
• /
• pp.18-24
• /
• 2020

본 연구의 목적은 화재사고가 발생한 건물에 인접한 LPG 탱크용 방화벽의 적용성을 검증하는 것이다. 제안된 방화벽 재료는 (1) 두께 10 mm 목재합판, (2) 내화도료를 도포한 목재합판, (3) 두께 75 mm Expanded Polystyrene, (4) 두께 75 mm 유리섬유 충진 샌드위치 판넬, (5) 두께 75 mm Autoclave Lightweight Concrete이다. 화원은 1 m 정사각형으로 120-140 g/s의 LPG를 균일하게 분사하여 방화벽과 후단의 탱크를 가열한다. 적용성은 시험 후 방화벽의 구조적 건전성 확인, 방화벽 양면 및 탱크표면 온도, 탱크 인근 복사열을 분석하여 판단한다. 그 결과, ALC 방화벽이 유일하게 구조 건전성을 유지하였고 저장탱크 온도를 가작 적게 상승시켜 폭발 방지 적용성을 확인하였다. 본 실험결과를 활용하여 방화벽의 성능평가 기준 마련에 필요한 핵심인자를 도출하였다.

• 대한원격탐사학회지
• /
• 제24권4호
• /
• pp.289-298
• /
• 2008

본 연구에서는 에어로솔의 간접 효과를 고려한 구름의 광학두께와 유효입자반경을 산출하기 위해 새로운 알고리즘을 개발하였다. 구름의 미세물리적 특성을 산출하기 위해 Nakajima and Nakajima(1995)의 방법을 응용하였다. 다양한 대기상태에서 복사전달모델을 이용하여 미리 계산한 서로 다른 LUT을 적용하여 최종 산출물인 구름광학두께와 유효입자반경을 산출하였다. 러시아지역에 산불이 있었던 2003년 5월 한반도 주변을 사례로 선택하였다. 이 때 발생한 에어로솔은 대기 흐름을 따라 한반도까지 도달하여 한반도 주변의 날씨에 매우 많은 영향을 주었다. 본 연구에서는 이 시기에 러시아 지역의 산불로 인하여 발생한 에어로솔이 한반도 주변의 구름에 어떠한 영향을 주는지 알아보았다. 이 사례의 알고리즘 적용을 위해 Terra위성에 탑재된 분광계인 MODIS자료를 사용하였다. 사례분석 결과, 에어로솔이 있는 시기에는 유효입자반경이 $20{\mu}m$ 이상의 큰 구름은 거의 존재하지 않았음에 비해, 에어로솔이 거의 없는 시기에는 $20{\mu}m$ 이상의 큰 구름도 다수 존재하였다. 즉, 에어로솔의 영향하에 발달한 구름은 구름광학두께는 크고, 유효입자반경은 작은 구름이라는 것을 확인할 수 있었다. 이러한 결과는 에어로솔이 구름의 미세물리적 특성을 변화시킨다는 것을 보여준다.