• Membrane and Water Treatment
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• v.12 no.1
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• pp.37-41
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• 2021

This paper presents the multiscale calculation results of the very fast volume transport in micro/nano cylindrical tubes with the wall slippage. There simultaneously occurs the adsorbed layer flow and the intermediate continuum fluid flow which are respectively on different scales. The modeled fluid is water and the tube wall is somewhat hydrophobic. The calculation shows that the power loss on the tube no more than 1.0 Watt/m can generate the wall slippage even if the fluid-tube wall interfacial shear strength is 1 MPa; The power loss on the scale 104 Watt/m produces the volume flow rate through the tube more than one hundred times higher than the classical hydrodynamic theory calculation even if the fluid-tube wall interfacial shear strength is 1 MPa. When the wall slippage occurs, the volume flow rate through the tube is in direct proportion to the power loss on the tube but in inverse proportion to the fluid-tube wall interfacial shear strength. For low interfacial shear strengths such as no more than 1 kPa, the transport in the tube appears very fast with the magnitude more than 4 orders higher than the classical calculation if the power loss on the tube is on the scale 104 Watt/m.

• Journal of Powder Materials
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• v.20 no.1
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• pp.19-23
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• 2013

Ru films were successfully prepared by plasma-enhanced atomic layer deposition (PEALD) using $Ru(EtCp)_2$ and $NH_3$ plasma. To optimize Ru PEALD process, the effect of growth temperature, $NH_3$ plasma power and $NH_3$ plasma time on the growth rate and preferred orientation of the deposited film was systemically investigated. At a growth temperature of $270^{\circ}C$ and $NH_3$ plasma power of 100W, the saturated growth rate of 0.038 nm/cycle was obtained on the flat $SiO_2$/Si substrate when the $Ru(EtCp)_2$ and $NH_3$ plasma time was 7 and 10 sec, respectively. When the growth temperature was decreased, however, an increased $NH_3$ plasma time was required to obtain a saturated growth rate of 0.038 nm/cycle. Also, $NH_3$ plasma power higher than 40 W was required to obtain a saturated growth rate of 0.038 nm/cycle even at a growth temperature of $270^{\circ}C$. However, (002) preferred orientation of Ru film was only observed at higher plasma power than 100W. Moreover, the saturation condition obtained on the flat $SiO_2$/Si substrate resulted in poor step coverage of Ru on the trench pattern with an aspect ratio of 8:1, and longer $NH_3$ plasma time improved the step coverage.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.3
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• pp.254-263
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• 2006

Manganese has a role as both toxic and essential in humans. Manganese is also an essential component in the welding because it increases the hardness and strength, prevents steel from cracking of welding part and acts as a deoxidizing agent to form a stable weld. In this study, manganese generation rate and its content was determined in flux cored arc welding on stainless steel. Domestic two products and foreign four products of flux cored wires were tested in the well designed fume generation chamber as a function of input power. Welding fume was measured by gravimetric method and metal manganese was determined by inductively coupled plasma-atomic emission spectrophotometer. The outer shell of the flux cored wire tube and inner flux were analyzed by scanning electron microscopy to determine their metal compositions. Manganese generation rate($FGR_{mn}$) was increased as the input power increased. It was 16.3 mg/min at the low input power, 38.1 mg/min at the optimal input power, and up to 55.4 mg/min at the high input power. This means that $FGR_{mn}$ is increased at the work place if welder raise the current and/or voltage for the high productivity. The slope coefficient of $FGR_{mn}$ was smaller than that of the generation rate of total fume(FGR). Also, the correlation coefficient of $FGR_{mn}$ was 0.65 whereas that of FGR is 0.91. $FGR_{mn}$ was equal or higher in the domestic products than that of the foreign products although FGR was similar. From the electron microscopic analytical data, we concluded that outer shell of the wire was composed mainly of iron, chromium, nickel and less than 1.2 % of manganese. There are many metal ingredients such as iron, silica, manganese, zirconium, titanium, nickel, potassium, and aluminum in the inner flux but they were not homogeneous. It was found that both $FGR_{mn}$ and content of manganese was higher and more varied in domestic flux cored wires than those of foreign products. To reduce worker exposure to fumes and hazardous component at the source, further research is needed to develop new welding filler materials that improve the quality of flux cored wire in respect to these points. Welder should keep in mind that the FGR, $FGR_{mn}$ and probably the generation rate of other hazardous metals were increased as the input power increase for the high productivity.

• Journal of Power System Engineering
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• v.8 no.3
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• pp.36-43
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• 2004

The effect of bath composition, plating condition and plating rate on the magnetic property of electroless Co-Cu-P deposits were investigated. With increasing $CuCl_2$ concentration in the bath, plating rate increased, while the Br value of deposit decreased sharply. Deposited surface were inferiority by the increase pH above 10.5, bath temperature higher than $80^{\circ}C$. Plating reaction had been ceased by the increase of pH above 11, bath temperature higher than $90^{\circ}C$ and under $40^{\circ}C$. The Br value of deposit was uniform with various concentration of complexing agent(sodium citrate) in the bath. The Br value of deposit was almost equal to that found by the addition of stabilizer (thiourea) and accelerator(NaF). The Br value of deposit was uniform in plating time(20min) and heat treatment temperature(below $200^{\circ}C$), and were confirmed to have adequate bath stability for practical use.

• Journal of Information Processing Systems
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• v.14 no.6
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• pp.1347-1360
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• 2018

Owing to limited energy in wireless devices power saving is very critical to prolong the lifetime of the networks. In this regard, we designed a cross-layer optimization mechanism based on power control in which source node broadcasts a Route Request Packet (RREQ) containing information such as node id, image size, end to end bit error rate (BER) and residual battery energy to its neighbor nodes to initiate a multimedia session. Each intermediate node appends its remaining battery energy, link gain, node id and average noise power to the RREQ packet. Upon receiving the RREQ packets, the sink node finds node disjoint paths and calculates the optimal power vectors for each disjoint path using cross layer optimization algorithm. Sink based cross-layer maximal minimal residual energy (MMRE) algorithm finds the number of image packets that can be sent on each path and sends the Route Reply Packet (RREP) to the source on each disjoint path which contains the information such as optimal power vector, remaining battery energy vector and number of packets that can be sent on the path by the source. Simulation results indicate that considerable energy saving can be accomplished with the proposed cross layer power control algorithm.

• Journal of Korean Physical Therapy Science
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• v.28 no.3
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• pp.76-87
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• 2021

Background: The purpose of this study was to evaluate the effects of power walking and square dancing on middle-aged women with hypertension. Design: Randomized controlled Trial. Methods: 30 middle-aged women with hypertension were selected and divided into two groups. 15 cases in the control group received routine treatment, and 15 cases in the intervention group received community vigorous walking and square dancing intervention on the basis of routine treatment. The intervention time was 40-60minutes/day, 5days/week, total 16 weeks. total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), angiotensin II (Ang II), Leptin, blood pressure, and heart rate were measured. Results: Body weight, body mass index (BMI), TC, TG, LOW-density lipoprotein, angiotensin II, leptin, systolic blood pressure and heart rate were significantly reduced after power walking and square dancing (p<0.05). After the experiment, TC and TG in the experimental group were lower than those in the control group (p<0.05), while HDL was higher (p<0.05). Conclusion: The results of this study suggest that power walking exercises and square dances are significant effects on lipid mechanism and heart rate.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.727-729
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• 2002

In this paper, we proposed quad variable rates ADPCM coding method and its implementation on C6000 DSP, which is modified from the standard ADPCM of ITU G.726 for speech quality improvement considering the environmental noise Four coding rates, 16Kbps, 24Kbps, 32Kbps and 40Kbps are used for speech window samples and the rate decision threshold is decided by the environmental noise level. The object of the proposed method is to reduce the coding rate while retaining the speech quality and the speech quality is considerably close to 40Kbps single rate coder with the coding rate close to 16Kbps single rate coder under the environmental noise. The environmental noise level affects the coding rate and the noise level is calculated per every speech window samples. At high noise level, more samples are coded at higher rates to enhance the quality, but at low noise level, only the big speech signals are coded at higher rates and more speech samples are coded at lower coding rates to reduce the coding rates. The influence of the noise on tile speech signal is considerably high for small signals and the small signal has the higher ZCR (zero crossing rate). The method is simulated in PC and to be implemented on C6000 floating point DSP board in real time operations.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.2
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• pp.119-126
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• 2002

In this study, general engine oil and the Miracle top engine oil of Dongjin chemistry company were tested to find the effects to the SI engine performance. Roller dynamometer used to find maximum power, fuel consumption rate and the emission. Maximum power was measured higher when the Miracle top engine oil was used in the vehicle. By use of the Miracle top engine oil, fuel consumption rate and emission was measured lower and compression pressure was higher compared use of general engine oil. Also the Miracle top engine oil was found to decrease the engine noise at the low RPM. And after 1,500km drive at the same condition, the dust in the oil pan and oil filter was measured less when the Miracle top engine oil used compared than general engine oil used.

• Proceedings of the KIEE Conference
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• summer
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• pp.677-679
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• 2004

Although Jeju is an island, its electricity demand is 430MW. It indicates electricity demand and its growth rate in Jeju are higher than mainland average. The supply of electricity in Jeju consists of power plants within the island and connection of main system using cable line. The cost of supply is higher than mainland system. However the electricity rate and DSM incentives were treated equally with mainland. Therefore, Effective DSM promotion has not been carried out. This paper analyzes the policy alternatives of supply in Jeju and presents effective DSM countermeasures. Also it presents long-term policy on stabilization of supply and demand in Jeju.

• Journal of Power System Engineering
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• v.19 no.4
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• pp.82-88
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• 2015

The purpose of this study is to investigate the effect of the impinging plate on combustion process in Diesel engine. Especially, the variation of exhaust emission and engine performance by the change of fuel injection timing and fuel injection pressure between the trial engine with impinging plate and the prototype engine were examined. The nitrogen oxide concentration of the trial engine decreased more than 50% compared to the prototype engine, however, smoke concentration of the trial engine indicated higher degree than the prototype engine. The smoke concentration, fuel consumption rate and exhaust gas temperature decreased as the fuel injection timing become faster, whereas the nitrogen oxide concentration decreased as the fuel injection timing is retarded. The nitrogen oxide concentration, fuel consumption rate and exhaust gas temperature decreased as the fuel injection pressure become lower. But smoke concentration decreased as the fuel injection pressure become higher.