• Title/Summary/Keyword: pin-hole

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A study on the brownish ring of quartz glass crucible for silicon single crystal ingot (실리콘 단결정 잉곳용 석영유리 도가니의 brownish ring에 대한 연구)

  • Jung, YoonSung;Choi, Jae Ho;Min, Kyung Won;Byun, Young Min;Im, Won Bin;Noh, Sung-Hun;Kang, Nam-Hun;Kim, Hyeong-Jun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.32 no.3
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    • pp.115-120
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    • 2022
  • A brown ring (hereinafter referred to as BR) on the inner surface of a quartz glass crucible used in the manufacturing process of a silicon ingot for semiconductor wafers was studied. BR is 20~30 ㎛ in size and has an asymmetric brown ring shape. The size and distribution of BR were different depending on the crucible location, and the size and distribution of BR were the largest and most abundant in the round part with the highest crucible temperature during Si ingot growth. BR contains cristobalite, which has a higher coefficient of thermal expansion than quartz glass, so it is considered that surface cracks appear. The color development of BR and pin holes are presumed to be due to oxygen vacancies.

STUDY ON THE RESTORATION MODEL OF JEONGNAM-ILGU, CREATED DURING THE REIGN OF KING SEJONG OF THE JOSEON DYNASTY (조선 세종대에 창제된 정남일구 복원모델 연구)

  • JIWON PARK;BYEONG-HEE MIHN;SANG HYUK KIM;YONG-GI KIM
    • Publications of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.1-12
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    • 2023
  • Numerous Sundials were fabricated during the reign of King Sejong of the Joseon Dynasty. One among them is Jeongnam-Ilgu (the Fixing-South Sundial), where the time can be measured after setting up the suitable meridian line without a compass. We reconstructed the new Jeongnam-Ilgu model based on the records of 'Description of Making the Royal Observatory Ganui (簡儀臺記)' in the Veritable Record of King Sejong. Jeongnam-Ilgu has a summer solstice half-ring under a horizontal ring which is fixed to two pillars in the north and south, and in which a declination ring rotates around the polar axis. In our model, the polar axis matches the altitude of Hanyang (that is Seoul). There are two merits if the model is designed to install the polar axis in the way that enters both the north and south poles and rotates in them: One is that it is possible to fix the polar axis to the declination ring together with the cross-strut. The other is that a twig for hanging weights can be protruded on the North Pole. The declination ring is supposed to be 178 mm in diameter and is carved on the scale of the celestial-circumference degrees on the ring's surface, where a degree scale can be divided into four equal parts through the diagonal lines. In addition, the time's graduation that is drawn on the summer solstice half-ring makes it possible to measure the daytime throughout the year. An observational property of Jeongnam-Ilgu is that a solar image can be obtained using a pin-hole. The position cast by the solar image between hour circles makes a time measurement. We hope our study will contribute to the restoration of Jeongnam-Ilgu.

Study of Simultaneous Counting of Thyroid Uptake with Quantitative Analysis of Thyroid Scans (갑상샘 스캔 정량분석을 통한 갑상샘 섭취율 동시계측법 연구)

  • Jung-Soo Kim;Geun-Woo Kim
    • Journal of radiological science and technology
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    • v.46 no.5
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    • pp.401-408
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    • 2023
  • Thyroid uptake measurements can be subject to measurement errors due to the scoping and positioning of the thyroid gland. To compensate for these limitations, the clinical utility of the thyroid simultaneous counting method as an alternative to thyroid uptake measurement was analyzed and evaluated experimentally through quantitative analysis of images acquired after thyroid scanning. Experimental data were obtained using a Gamma camera (GE infinia), a thyroid uptake system (KOROID 1), and a thyroid neck phantom. Based on the thyroid uptake rate of 1-5% according to the protocol of thyroid scan test (99mTcO4 - , 370 MBq) in normal results, 99mTcO4 - was set in the range of 3.7-18.5 MBq (Matrix: 256×256, Scan time: 1 min, collimator: pin hole, phantom-collimator distances: 7 cm). The acquired images were corrected for the attenuation of isotopes due to the set-up time and half-life by applying the Auto Region of interest (ROI) drawing system, and the significance of the experimental results was evaluated by Multiple linear regression analysis (SPSS, ver. 22, IBM). The thyroid uptake rate showed a significant correlation between the dose and the measured counts when using the thyroid uptake system equipment. Meanwhile, the quantitative analysis counts of phantom images using Gamma camera also showed a significant correlation. Thus confirmed that the correlation between these two experiments was statistically significant (P<0.05). The simultaneous counting protocol, which indirectly measures thyroid uptake from thyroid scans, is likely to be clinically relevant if complemented by additional studies with different variables in patients with thyroid disease.

Modification of NiO Using 2PACz for P-i-n Perovskite Solar Cells (P-i-n 페로브스카이트 태양전지 응용을 위한 2PACz을 이용한 NiO의 개질)

  • Seon-Min Lee;Seok-Soon Kim
    • Applied Chemistry for Engineering
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    • v.35 no.2
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    • pp.100-106
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    • 2024
  • To improve charge transfer and surface contact between NiO and perovskite, sol-gel derived NiO is modified with [2-(9H-car-bazol-9-yl)ethyl] phosphonic acid (2PACz) in p-i-n structured perovskite solar cells (PeSCs). The phosphonic acid head group in the 2PACz can bind to the hydroxyl groups on the surface of NiO by a condensation reaction, which results in a better-matched energy level with the valence band of perovskite layers, reducing nonradiative recombination and energy loss. Furthermore, the formation of pin-hole free perovskite films is observed in the 2PACz modified NiO system. Consequently, the combination of sol-gel processed NiO with optimal 2PACz exhibits a higher efficiency of 17.08% and superior stability under ambient air conditions without any encapsulation, compared to a bare NiO based device showing 13.69%.

A Study on the Leakage Protection with Polypropylene Mat in Irrigation Canal (Polypropylene Mat에 의(依)한 용수로(用水路)의 누수방지(漏水防止)에 관(關)한 연구(硏究))

  • Kang, Sin-Up;Kang, Yea-Mook;Cho, Seung-Seup
    • Korean Journal of Agricultural Science
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    • v.6 no.2
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    • pp.166-184
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    • 1979
  • In order to prevent the water loss in the irrigation canal constructed on the sandy gravel layer or on the other highly permeable ground layer, lining has been practiced. Many studies have been done so far on the lining method to prevent the water loss in the irrigation canal and recently studies on the lining with plastic film or polyethylene film were also reported. However, the plastic film or polyethylene film has low strength and is liable to break, and water loss from pin hole caused by contacting with sand or gravel is highly predicted. This study was then conducted to find proper lining and buring method in canal construction of polypropylene mat after coated with vinyl, as one way to overcome the shortcoming frequently observed when plastic or usual polyehtylene film were used. Eventhough rather longer periods of experiments are needed to attain reliable and accurate results on the variation of durability, the durability of asphalt coated area, or on the damage due to freeze after burial or exposure of polypropylene mat, the experiemental results obtained during one year of period are summarized as follows: 1. The curvature at the area between canal bottom and side slope had increased stability and saved consruction cost. The relationship among the variation of curvature, the reduction of polypropylene mat and the reduced amount of soil cutting at each side slope was presented in Fig. 7 through 9. 2. The depth of covering material to protect polypropylene mat was desired to be over 30cm, considering the water depth, side slope, canal cleaning practices, traffic, or back pressure of irrigation period. 3. In order to increase the canal stability and to prevent slope erosion, sandy soil was required, to be placed under ground, and coarse gravel should cover the surface area of canal. 4. The studies on the stability of side slope in the canal should consider the passive area on the bottom and the slope should be about 1 to 2, considering the slope stability, allowable velocity and tractive force. 5. When compared with earth lining, the lining with polypropylene mat coated with vinyl was responsible to save 28% and 37% of canal lining cost, when the soil carrying distances were 500 and 700m. respectively. 6. The water interception was almost completely attained when the polypropylene mat coated with vinyl was used for lining. But further studies were assumed to be necessary for the use of asphalt since the strength of polypropylene mat connected with asphalt will vary with duration.

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Research on The Utility of Acquisition of Oblique Views of Bilateral Orbit During the Dacryoscintigraphy (눈물길 조영검사 시 양측 안 와 사위 상 획득의 유용성에 대한 연구)

  • Park, Jwa-Woo;Lee, Bum-Hee;Park, Seung-Hwan;Park, Su-Young;Jung, Chan-Wook;Ryu, Hyung-Gi;Kim, Ho-Shin
    • The Korean Journal of Nuclear Medicine Technology
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    • v.18 no.1
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    • pp.76-81
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    • 2014
  • Purpose: Diversity and the lachrymal duct deformities and the passage inside the nasal cavity except for anterior image such as epiphora happens during the test were able to express more precisely during the dacryoscintigraphy. Also, we thought about the necessity of a method to classify the passage into the naso-lachrymal duct from epiphora. Therefore, we are to find the validity of the method to obtain both oblique views except for anterior views. Materials and Methods: The targets of this research are 78 patients with epiphora due to the blockage at the lachrymal duct from January 2013 to August 2013. Average age was $56.96{\pm}13.36$. By using a micropipette, we dropped 1-2 drops of $^{99m}TcO4^-$ of 3.7 MBq (0.1 mCi) with $10{\mu}L$ of each drop into the inferior conjunctival fold, then we performed dynamic check for 20 minutes with 20 frames of each minute. In case of we checked the passage from both eyes to nasal cavity immediately after the dynamic check, we obtained oblique view immediately. If we didn't see the passage in either side of the orbit, we obtained oblique views of the orbit after checking the frontal film in 40 minutes. The instrument we used was Pin-hole Collimator with Gamma Camera(Siemens Orbiter, Hoffman Estates, IL, USA). Results: Among the 78 patients with dacryoscintigraphy, 35 patients were confirmed with passage into the nasal cavity from the anterior view. Among those 35 patients, 15 patients were confirmed with passage into the nasal cavity on both eyes, and it was able to observe better passage patterns through oblique view with a result of 8 on both eyes, 2 on left eye, and 1 on right eye. 20 patients had passage in left eye or right eye, among those patients 10 patients showed clear passage compared to the anterior view. 13 patients had possible passage, and 30 patients had no proof of motion of the tracer. To sum up, 21 patients (60%) among 35 patients showed clear pattern of passage with additional oblique views compared to anterior view. People responded obtaining oblique views though 5 points scale about the utility of passage identification helps make diagnoses the passage, passage delayed, and blockage of naso-lachrymal duct by showing the well-seen portions from anterior view. Also, when classifying passage to naso-lachrymal duct and flow to the skin, oblique views has higher chance of classification in case of epiphora (anterior:$4.14{\pm}0.3$, oblique:$4.55{\pm}0.4$). Conclusion: It is considered that if you obtain oblique views of the bilateral orbits in addition to anterior view during the dacryoscintigraphy, the ability of diagnose for reading will become higher because you will be able to see the areas that you could not observe from the anterior view so that you can see if it emitted after the naso-lachrymal duct and the flow of epiphora on the skin.

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Two Efficient Methods for Generating Depth-of-Field (효율적인 피사계 심도 생성을 위한 두 가지 기법)

  • Suh, Young-Seon;Ihm, In-Sung
    • Journal of the Korea Computer Graphics Society
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    • v.14 no.3
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    • pp.31-46
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    • 2008
  • The depth of field is the range that the objects inside of this range treated to be focused. Objects that are placed out of this range are out of focus and become blurred. In computer graphics, generating depth of field effects gives a great reality to rendered images. The previous researches on the depth of field in computer graphics can be divided into two major categories. One of them is the distributed ray tracing that samples the lens area against each pixel. It is possible to obtain precise results without noise if enough number of samples are taken. However, to make a good result, a great number of samples are needed, resulting in an enormous timing requirement. The other approach is the method that approximates depth of field effect by post-processing an image and its depth values computed using a pin-hole camera. Though the second technique is not that physically correct like distributed ray tracing, many approaches which using this idea have been introduced because it is much faster than the first approach. But the post-processing have some limitations because of the lack of ray information. In this paper, we first present an improvement technique that corrects the previous post-processing methods and then propose another one that accelerates the distributed ray tracing by using a radiance caching method.

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Phase identification and degree of orientation measurements far fine-grained rock forming minerals using micro-area X-ray diffractometer -$Al_{2}SiO_{5}$ Polymorphs- (미소부 X-선 회절분석기를 이용한 미립조암광물의 상동정 및 배향도 측정 -$Al_{2}SiO_{5}$ 3상다형-)

  • 박찬수;김형식
    • The Journal of the Petrological Society of Korea
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    • v.9 no.4
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    • pp.205-210
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    • 2000
  • Measurements of phase identification and degree of orientation for fine-grained (about 0.3 mm in diameter) minerals in rock samples performed by micro-area X-ray diffractometer.$Al_{2}SiO_{5}$ polymorphs (andalusite, kyanite and sillimanite) were chosen for the measurements and target minerals were existed on thin sections. Micro-area X-ray diffractometer is composed of 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillating goniometer and position sensitive proportional counter (PSPC). $CuK_{\alpha}$ radiation was used as X-ray source and a pin hole ($50\;\mu\textrm{m}$$ in diameter) collimator was selected to focus radiation X-ray onto the target minerals. Phase identification and diffracted X-ray peak indexing were carried out by 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillation measurement. Then, 2(${\omega}\;{\phi}$)-circle oscillation measurement was made for the purpose of searching the prevailing lattice plane of the minerals on thin section surface. Finally, for a selected peak by 2-circle oscillation measurement, X-ray pole figure measurement was executed for the purpose of check the degree of orientation of the single lattice direction and examine its pole distribution. As a result of 3-circle oscillation measurement, it was possible that phase identification among $Al_{2}SiO_{5}$ polymorphs. And from the results of 2-circle oscillation measurement and X-ray pole figure measurement, we recognized that poles of andalusite (122), kyanite (200) and sillimanite (310) lattice plances were well developed with direction normal to each mineral surface plane respectively. Therfore, the measurements used with micro-area X-ray diffractometer in this study will be a useful tool of phase identification and degree of orientation measurement for fine-grained rock forming minerals.

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A Study of Failure Mechanism through abnormal AlXOY Layer after pressure Cooker Test for DRAM device (DRAM 소자의 PCT 신뢰성 측정 후 비정상 AlXOY 층 형성에 의해 발생된 불량 연구)

  • Choi, Deuk-Sung;Jeong, Seung-Hyun;Choi, Chae-Hyoung
    • Journal of the Microelectronics and Packaging Society
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    • v.25 no.3
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    • pp.31-36
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    • 2018
  • This research scrutinizes the reason of failure after pressure cooker test (PCT) for DRAM device. We use the physical inspecting tools, such as microscope, SEM and TEM, and finally find the discolor phenomenon, corrosion of Al and delamination of inter-metal dielectric (IMD) in the failed devices after PCT. Furthermore, we discover the abnormal $Al_XO_Y$ layer on Al through the careful additional measurements. To find the reason, we evaluate the effect of package ball size and pinhole in passivation layer. Unfortunately, those aren't related to the problems. We also estimate halide effect of Al. The halogens such like Cl are contained within EMC material. Those result in the slight improving of PCT characteristics but do not perfectly solve the problems. We make a hypothesis of Galvanic corrosion. We can find the residue of Ti at the edge of pad open area. We can see the improving the PCT characteristics by the time split of repair etch. The possible mechanism of the PCT failure can be deduced as such following sequence of reactions. The remained Ti reacts on the pad Al by Galvanic corrosion. The ionized Al is easily react with the $H_2O$ supplied under PCT environment, and finally transfers to the abnormal $Al_XO_Y$ layer.

Evaluation of Anastomotic Strength and in-vitro Degradability with Microvascular Anastomosis Coupler Based on Injection Molding Condition made by Biodegradable Polycaprolactone(PCL) (생체분해성 폴리카프로락톤(PCL) 미세혈관 문합커플러의 사출성형조건에 따른 문합강도 및 in-vitro 분해능 평가)

  • Ahn, Geun-Seon;Han, Gig-Bong;Oh, Seung-Hyun;Park, Jong-Woong;Kim, Cheol-Woong
    • Transactions of the KSME C: Technology and Education
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    • v.1 no.2
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    • pp.167-177
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    • 2013
  • The use of mechanical anastomosis coupler instead of sutures has been increasing in microvascular anastomosis surgery. However, non-biodegradable anastomosis coupler has problems such as not only inflammatory reaction but also remaining permanently in operation wound. Therefore, we fabricated biodegradable anastomosis coupler using injection molding process to overcome the limitation of non-biodegradable anastomosis coupler. In various injection molding process conditions, the shrinkage was calculated with different cylinder temperatures and injection molding pressures and anastomotic strength was measured. As a result, changes in shrinkage hole part larger than the pin part. In addition, the shrinkage in the cylinder at higher temperatures increase. However, the higher the injection pressure, shrinkage tends to decrease, respectively. In-vitro degradation behavior of PCL anastomotic coupler evaluated for 12 weeks, water uptake was increased and molecular weight was accompanied by a reduction in mass of the biological degradation and reduction of anastomotic strength was confirmed. However, decreased levels of anastomotic strength enough to exceed the requirements of preclinical surgery, PCL microvascular anastomosis coupler suitable candidate materials that could identify.