• Journal of Radiation Protection and Research
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• v.16 no.2
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• pp.41-54
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• 1991

This paper aimed to analyse dose sensitivity to the controllable parameters of indoor radon $(^{222}Rn)$ and its decay products (Rn-D) by applying the input~output linear system theory. Physical behaviors of $^{222}Rn\;&\;Rn-D$ were analyzed in terms of $(^{222}Rn)$ gas -generation, -migation and -infiltration to indoor environments, and the performance output-function, i. e. mean dose equivalent to Tracho-Bronchial (TB) lung region, was assessed to the following extented ranges of the controllable paramenters; a) the ventilation rate $constant({\lambda}_v)\;:\;0{\sim}50[h^{-l}].\;b)$ the attachment rate $constant({\lambda}_a)\;:\;0{\sim}500[h^{-l}].\;c)$ the unattached-deposition rate constant (${\lambda}^u_d)\;:\;0-50[h-l]$. A linear input-output model was reconstructed from the original models in literatures, as follows, which was modified into the matrices consisting of 111 nodal equations; a) indoor $^{222}Rn\;&\;Rn-D$ Behaviour; Jacobi-Porstendoerfer-Bruno model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.439-444
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• 2011

To determine the test gases for gas appliances of new gas group, the interrelation between gas interchangeability, including thermal efficiency, of 13A gas appliances and present 13A test gases was experimentally investigated. The test results show that the Wobbe indices in the case of incomplete combustion and the flame lifting limit gas for the new gas group are respectively 2% higher than the upper limit and 1% lower than the lower limit of the Wobbe index range. The most suitable composition of R gas is 96 mol% of methane and 4 mol% of propane; LNG could be also used as R gas. Further, analysis results showed that the hydrogen concentration of flash back limit gas could be lowered from 30 vol% to 23 vol%.

• Clean Technology
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• v.13 no.4
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• pp.251-256
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• 2007

Several studies regarding depolymerization of polycarbonate waste to get the essential monomer, bisphenol A, have been reported in recent years. However, those methods have some environmental safety problems of using highly toxic organic solvents as well as product separation problem due to the use of alkali catalyst. In this study, we proposed the combination of glycolysis and methanolysis to depolymerize the polycarbonate waste. Glycolysis reaction reached at the reaction equilibrium after about 180 minat 473.15K and dissolution of the polycarbonate was found to be a rate controlling step of the reaction. The yield of BPA was improved with the aid of combination of glycolysis and methanolysis. The methanolysis was carried out at a temperature range of $303.15K{\sim}363.15K$ and MeOH/PC molar ratio $0.5{\sim}3$. The yield of BPA had a maximum at 1.0 MeOH/PC molar ratio and increased with the reaction temperature.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.9
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• pp.961-967
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• 2011

The objective of this study was to develop a new method for estimating gas interchangeability for 13A gas appliances. The three basic principles for the development of this method are as follows: 1) to derive the secondary interchangeability factor that represents the effect of gas composition, in addition to the major interchangeability factor, i.e., Wobbe index; 2) to test every type of and each maker's domestic gas appliances that are widely used in our country, particularly including premixed gas appliances; and 3) to develop a simple estimation method. On the basis of these principles, thirty representative gas appliances were tested, and as a result, a simple two-dimensional interchangeability diagram consisting of Wobbe index and relative density was developed. Unlike conventional methods for estimating interchangeability, this method can be applied to premixed gas appliances, which have a narrow stable flame range, and the interchangeability range of this method then becomes narrower than that of the conventional methods.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.703-708
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• 2013

Conventional total hip joint replacement(THR) surgery requires a long incision and long rehabilitation time. The stem used in THR is inserted into the cancellous bone of the femur where it plays the role of the artificial joint. Minimally invasive surgery(MIS) has been devised to reduce muscle damage to patients. In this study, a mechanical stem was developed on the basis of MISto reduce the incision length through the principle of the gear. The mechanical stem consists of six components. A prototypical model for a mechanical stem was fabricated using an acryl-based polymer, and its workability was confirmed. To actualize the mechanical stem, a three-dimensional Bio-CAD modeling technique was applied. The hip joint area based on computed tomography(CT) was reconstructed. The safety of the mechanical stem by applying more load than the weight of a man under virtual surgery environment conditions was confirmed by finite element analysis.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5597-5600
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• 2014

Objectives: To assess side effects on Cantharidin sodium and Shenmai injection combined with chemotherapy in treating patients with breast cancer postoperatively. Method: Patients with breast cancer receiving postoperative chemotherapy were retrospectively collected, and divided into four groups: group A with cantharidin sodium injection combined with chemotherapy; group B with Shenmai injection combined with chemotherapy; group C with both cantharidin sodium and Shenmai injection combined with chemotherapy; while group D (control group) received chemotherapy alone. All patients were administered docetaxel at a dose of $75mg/m^2$ on day 1, epirubicin hydrochloride at a dose of $60mg/m^2$ on day 1, and cyclophosphamide at a dose of $500mg/m^2$ on day 1 for 3 cycles (repeated at 21 day intervals). After ${\geq}$ three courses of treatment, quality of life and side effects were evaluated. Results: There were a total of 78 patients in this study, and the incidence of leukopenia and gastrointestinal reactions in groups A and B were lower than those in the control group and lowest in group C (p<0.05). Conclusions: Thus cantharidin sodium and Shenmai injection combined with chemotherapy reduce side effects and deserve to be further investigated in randomized clinical control trials.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.3
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• pp.149-155
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• 2016

Early detection of toxic gases, such as volatile organic compounds (VOCs), is important for safety and environmental protection. However, the conventional detection methods require long-term measurement times and expensive equipment. In this study, we propose a thin-film-type chemical sensor for VOCs, which consists of self-assembled monosize nanoparticles for 3-D photonic crystal structures and polydimthylsiloxane (PDMS) film. It is operated without any external power source, is truly portable, and has a fast response time. The structure color of the sensor changes when it is exposed to VOCs, because VOCs induce a swelling of the PDMS. Therefore, using this principle of color change, we can create a thin-film sensor for immediate detection of various types of VOCs. The proposed device evidences that a fast response time of just seconds, along with a clear color change, are successfully observed when the sensor is exposed to gas-phase VOCs.

• Textile Coloration and Finishing
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• v.21 no.1
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• pp.1-9
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• 2009

A lot of research has been made over the recent decade to develop testing packages with antimicrobial properties to improve food safety. In this study, a new method, experimental device and technology for environmental corresponding packages of polypropylene (PP) film has been developed to provide effective temperature buffering during the transport/long-term storage of grains or foodstuffs from the supplier to the market. This quantitatively optimized mixing system enabled to produce PP films with the 700$\sim$1,400d (width;1.5$\sim$3mm, thickness;0.01$\sim$0.5mm). In the whole mixing systems, the finely-granulated inorganic illite and PP virgin chip for master batch (M/B) chip was calculated by digital measurement methods, and then the M/B chip for PP film was adapted through a air jet and PP grinding method. The prepared PP film was characterized with tensile strength and elongation, far infrared radiation (FIR) emissivity, antimicrobial activity and deodorization properties. The results revealed that the two differently grain-sized illite could be show homogeneously dispersed on PP chip surface, and as the increasing of illite content, the FIR emissivity and the anion emission rate of film was increasingly improved. In both of 325 and 1,500 mesh-sized illite contained PP chip, of course the antimicrobial activity was good. But the ultimate deodorization rate for ammonia gas of PP film were found to be approximately the same.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.42-51
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• 2018

Verticality problem during the installation process in offshore wind turbine substructures could degrade the safety of the whole structures. Therefore, in this paper, the design of vertically adjustable transition piece(T.P.), using a PS anchor and grout of anchor socket in concrete gravity based substructure(G.B.S.), was proposed. T.P. was designed for 5MW offshore wind trubine and can adjust up to $0.5^{\circ}$ in verticality, occurred during installation. The design plan for each members and design procedure for T.P. was proposed. Then based on the proposed design, actual design targeting sea of Jeju-island was carried out. Finally, by use of non-linear 3D Finite Element Analysis(F.E.A.), evaluation of design was performed. As a result of evaluation, by checking load transfer mechanism and stress of T.P, proposed design was considered safe up to $0.5^{\circ}$ of adjustment.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.19-26
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• 1995

The assessment of maneuverability of a ship is very important from the view point of safety of human beings and of pollution of ocean. And, it is quite natural that every ship yard wants to have some tools with which they can build a ship with good maneuverability. But, maneuvarability of a ship is very subtle problem, and to calculate the exact maneuvering motion, lots of captive model tests must be carried out. Futhermore, in the initial design stage we can not make the scale model, because the lines of a ship is not fixed. In this paper, some approximate method to calculate the maneuvering motion of a ship, with the principal dimensions of hull, and propeller, rudder characteristics only, is studied. And, proposed approximate method is used to calculate the turning and zig-zag maneuver of several ships. The results of those calculations and the usability of the method are discussed.