• Clean Technology
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• v.21 no.2
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• pp.96-101
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• 2015

Hematite reduction using hydrogen was conducted and the various process parameters were closely observed. A lab scale fluidized bed unit was designed especially for this study. The optimal values of the gas velocity, reduction time and temperature were evaluated. The values which indicated the highest reduction rate were set as fixed parameters for the following tests starting with the reduction time of 30 minutes and 750 ℃ of temperature. Among these variables the one with the highest interest was the gas specific consumption. It will tell the amount of the gas which is required to achieve a reduction rate of over 90% at the optimal conditions. This parameter is important for the scale up of the lab scale unit. 1,500 Nm³/ton-ore was found to be the optimal specific gas consumption rate at which the reduction rates exhibit the highest values for hematite.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1329-1334
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• 2006

The electrochemical reduction of coumarin, 7-acetoxy-4-methyl coumarin (AMC), and 7-acetoxy-4-bromomethyl coumarin (ABMC), in 0.1 M tetraethyl ammonium perchlorate/acetonitrile solution was carried out by direct current, differential pulse polarography, cyclic voltammetry, and controlled potential coulometry. The electrochemical reduction of ABMC was proceeded through three steps of electron transfer coupled with the chemical reactions. The color of solution was changed to yellow when the carbonyl group was reduced during 2nd step (-1.8 volts) and independented with cleavage of bromo group. Highest fluorescence intensity showed when the electrochemical reduction of AMC was controlled at near the potential (-2.3 volts vs. Ag/AgCl).

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.463-466
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• 2002

In order to examine the possibility of using a cavity as a passive device for reduction of skin friction and heat transfer, an intensive parametric study over a broad range of the cavity depth and length at different Reynolds numbers is performed for both laminar and turbulent boundary layers in the present study. Direct and large eddy simulation techniques are used for turbulent boundary layers at low and moderate Reynolds numbers, respectively. for both laminar and turbulent boundary layers over a cavity, a flow oscillation occurs due to the shear layer instability when the cavity depth and length are sufficiently large and it plays an important role in the determination of drag and heat-transfer increase or decrease. For a cavity sufficiently small to suppress the flow oscillation, both the total drag and heat transfer are reduced. Therefore, the applicability of a cavity as a passive device for reduction of drag and heat transfer is fully confirmed in the present study. Scaling based on the wall shear rate of the incoming boundary layer is also proposed and it is found to be valid in steady flow over a cavity.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.857-862
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• 2004

Production of titanium powder directly from tantalum oxides ($TiO_2$) pellet through an electronically mediated reaction (EMR) by calciothermic reduction has been investigated. Feed material ($TiO_2\;pellet$) and reductant (Ca-Ni alloy) were charged into electronically isolated locations in a molten calcium chloride ($CaCl_2$) bath at $950^{\circ}C$. The current flow through an external circuit between the feed (cathode) and reductant (anode) locations was monitored during the reduction of $TiO_2$. The current approximately 3.2A was measured during the reaction in the external circuit connecting cathode and anode location. After the reduction experiment, pure titanium powder with low nickel content was obtained even though Ca-Ni alloy was used as a reductant. These results demonstrate that titanium powder can be produced without direct physical contact between the feed and reductant. In certain experimental conditions, pure titanium powder with approximately $99.5\;mass\%$ purity was successfully obtained.

• Journal of the Korean Chemical Society
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• v.39 no.1
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• pp.57-65
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• 1995

The electrochemical reduction of methylene blue (MB) in 1.0${\times}$10-2 M KNO3 aqueous solution was investigated by direct current (DC), differential pulse (DP) polarography, cyclic voltammetry (CV) and controlled potential coulometry (CPC). The electrode reduction of melthylene blue was processed CE reaction mechanism by two electrons transfer at the first reversible wave (- 0.18 volts vs. Ag/AgCl). MB was strongly adsorbed on the stationary mercury electrode and the reduction product of conptrolled potential electrolysis was rapidly auto-oxidized in air to the original methylene blue. Upon the basis of interpretation of cyclic voltammogram with pH change, possible CE electrode reaction mechanism was suggested.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.5
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• pp.281-291
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• 2020

Background: Corticosteroids have been widely used by oral surgeons for reducing swelling caused by wisdom teeth surgery. However, they have not been proven to decrease pain. This study was aimed at analyzing previous studies pertaining to corticosteroids and pain reduction following wisdom teeth surgery. Methods: The Science Direct, PubMed, and MEDLINE databases were searched for relevant journals according to a systematic search strategy (Patient Intervention Comparison Outcome Study). Randomized controlled trials published in English from 1998 to 2017 were extracted. Results: Twenty-seven articles were included, with a total of 36 comparative cases. Methylprednisolone and dexamethasone were the most commonly used corticosteroids. Intramuscular injections of corticosteroids were optimal for pain reduction, regardless of the time of administration. Conclusions: Corticosteroids can be used as an adjuvant for pain reduction following wisdom teeth surgery. Methylprednisolone and dexamethasone delivered via the intramuscular route is the best method for effective pain reduction. The ideal time for administration of corticosteroids is the preoperative period.

• Journal of the International Relations & Interdisciplinary Education
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• v.4 no.1
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• pp.35-56
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• 2024

Based on Kingdon's policy stream model, the logical mechanism of student burden double reduction policy agenda setting process in China was analyzed from three aspects: problem stream, policy stream, political stream. It was found that the direct reflection of data, the feedback and improvement of current policies constitute the problem stream.The high attention of government departments, the suggestions of CPPCC members and experts and scholars, the strong voice of schools, and the continuous voice of stakeholders constitute the policy stream. The ruling party's governing idea and educational policy, national mood and interest game during the transition period constitute the political policy stream. The three streams, coupling interaction, open the policy window, promoting the introduction of the 'double reduction' policy.

• Archives of Craniofacial Surgery
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• v.10 no.1
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• pp.33-36
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• 2009

Purpose: Fractures of the mandibular condylar area are common injuries that account for 29% to 40% of fractures of the facial bones and represent 20% to 62% of all mandibular fractures. Currently 3 main methods are being used in the treatment of mandibular subcondylar fractures: closed reduction; open reduction and internal fixation; Endoscopic reduction and internal fixation. Each method has its proponents and opponent as well as advantages and disadvantages, and indications for each vary among surgeons. There are six approaches of open reduction: submandibular, retromandibular, preaurilcular, postauricular, intraoral, transparotid approach. Among them, transparotid approach has been described for subcondylar exposure with dissection in the direction of facial nerve fibers to expose the bone through the parotid gland. This approach carries the risk of a parotid glandular fistula as well as facial nerve injury but has the advantage of being directly over the fracture site. We report safety and efficacy of surgical treatment using a transparotid approach for direct plating. Methods: A 43-year-old man sustained multiple facial bone fractures by driver traffic accident. Mandibular subcondyle was fractured and dislocated internally. We performed open reduction and internal fixation by transparotid approach. Fractured site was fixed by titanium mini plate & screw. We applicated arch bar for approximately 3 weeks. Results: Follow-up length was about 5months. Scar of surgical incision was indistinct, there was no symptoms and signs of facial nerve and parotid gland injury, and maximal mouth opening was measured 49.5 mm. Conclusion: Transparotid approach has high risks of facial nerve and parotid gland injury, but paradoxically it is the most effective technique in saving facial nerve. Open reduction and internal fixation of mandibular subcondylar fracture by transparotid approach with precise and versed procedure, best outcome can be expected.

• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.29-34
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• 2009

In this study, a chloride ion probe as a direct measurement for perchlorate reduction was used to determine whether biological perchlorate reduction was inhibited by other electron acceptors ($O_2$ and ${NO_3}^-$) and to investigate competition of electron acceptors for using electron donors. Profiles of chloride production (= perchlorate reduction) in flasks containing perchlorate reducing populations were monitored by a chloride ion probe. Biological reduction of 2 mM perchlorate was inhibited by 2 mM nitrate that chloride production rate was decreased by 30% compared to perchlorate used as the only electron acceptor and chloride production rate was decreased by 70% when acetate was limited. Reduction of 2mM perchlorate was completely inhibited by oxygen at 7~8 mg/L, regardless of acetate excess / limitation.

• Archives of Plastic Surgery
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• v.35 no.4
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• pp.465-470
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• 2008

Purpose: Reduction malarplasty is a popular aesthetic surgery for contouring wide and prominent zygoma. However a few patients complain postoperative results and want to revise the midfacial contour. We analyzed the etiology of unfavorable results and treated unsatisfied midfacial contours after reduction malarplasty. Methods: Total 53 patients were performed secondary operation for correction of unfavorable results after primary reduction malarplasty from elsewhere. Midfacial contour was evaluated with plain films and three-dimensional computed tomography. Unfavorable midfacial contours were corrected by secondary malarplasty. Flaring of zygomatic arch was reduced with infracturing technique and prominent zygomatic body was reduced with shaving. Drooped or displaced zygoma complex has been suspended to higher position and fixed with interosseous wiring. As adjuvant procedure, autologous fat injection has been performed in the region of depressed zygomatic body region. Results: The etiology of unfavorable midfacial contour after reduction malarplasty was classified into 7 categories: undercorrection of zygomatic arch(n=8), undercorrection of zygomatic arch and undercorrection of zygomatic body(n=6), undercorrection of zygomatic arch and overcorrection of zygomatic body(n=28), overcorrection of zygomatic body(n=3), simple asymmetry(n=4), malunion(n=2) or nonunion(n=2). Slim and balanced malar contour was achieved with treatment. And most of the patients were satisfied with the results of the surgery. Conclusion: To prevent the unfavorable results after reduction malarplasty, complete analysis of facial contour, choice of appropriate operation technique, precise osteotomy under direct vision, and security of zygoma position are important.