• Bulletin of the Korean Chemical Society
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• v.18 no.2
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• pp.213-217
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• 1997

Magnesium reduction of Mo(N-C6H3-2,6-i-Pr2)2Cl2(DME) in the presence of trimethylphosphine led to a mixture of Mo(N-C6H3-2,6-i-Pr2)(PMe3)2Cl3, 1, and Mo2(PMe3)4Cl4, 2. In solution 1 is slowly air-oxidized to Mo(N-2,6-i-Pr2-C6H3)(OPMe3)(PMe3)Cl3, 3. 1 is chemically inert to carbon nucleophiles (ZnMe2, ZnEt2, AlMe3, AlEt3, LiCp, NaCp, TlCp, NaCp*, MeMgBr, EtMgBr), oxygen nucleophiles (LiOEt, LiO-i-Pr, LiOPh, LiOSPh), and hydrides (LiBEt3H, LiBEt3D). Crystal data for 1: orthorhombic space group P212121, a=11.312(3) Å, b=11.908(3) Å, c=19.381(6) Å, Z=4, R(wR2)=0.0463 (0.1067). Crystal data for 2: monoclinic space group Cc, a=18.384(3) Å, b=9.181(2) Å, c=19.118(3) Å, b=124.98(1)°, Z=4, R(wR2)=0.0228 (0.0568). Crystal data for 3: orthorhombic space group P212121, a=11.464(1) Å, b=14.081(2) Å, c=16.614(3) Å, Z=4, R(wR2)=0.0394 (0.0923).

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.483-492
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• 2008

The characteristics of joint system (joint orientation and density) were studied for Cretaceous sedimentary rocks in the Nakdong River mid-basin (Haman-Gun, Changnyeong-Gun, and Uiryeong-Gun areas), and were related with faults, river system, and groundwater usage in the study area. The joint system was classified into JI ($N90^{\circ}-110^{\circ}E$), J2 ($N0^{\circ}-35^{\circ}E$), and J3 ($(N0^{\circ}-35^{\circ}W$), and was dominant along N-S and E-W directions. The N-S trending joint system is dominant in Haman Formation in the eastern and western parts of the study area, while the E-W trending joint system is prevalent in Chilgok Formation in the central part. The joint system may be associated with the faults located in the eastern and western parts in the study area which are elongated to NNE-SSW direction. Additionally, the joint density is higher along the Nakdong River, indicating close relationship between E-W trending joints and the river. Daily groundwater discharge versus joint density shows weak positive relationship, and specific capacity versus joint density appears negatively related. This indicates that groundwater occurrence does not greatly rely on joint density.

• Fire Science and Engineering
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• v.29 no.6
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• pp.1-5
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• 2015

In this study, the combustion characteristics of Hinoki Cypress Louver were measured after performing pressure impregnation with aqueous solution of boric acid, borax, and ammonium phosphate. The characteristics measured include ignition time, critical heat flux, and mass loss rate by incident hear flux (25, 30 and $50kW/m^2$). The samples used for the test were $100{\times}100{\times}10mm$, and the 5 min variation for each incident heat flux was measured 3 times. The results show that the ignition time for incident heat flux of $25kW/m^2$ showed a delay effect of 17.4 to 21.3% except for Type C-H. There was no significant difference at 35 and $50kW/m^2$ in the average mass loss rate in Types A-H and D-H, which had lower rates than Type N-H, which was predicted to be higher than that of Type N-H ($10.7kW/m^2$) by 38.22 to 60.46%. It is thus expected that at the time of initial primary fire, there would be a delay effect against fire spread.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.308-311
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• 2006

A vibration monitoring is performed on a 1kW class stand alone wind turbine(W/T). When a W/T model is developed, general performance under various wind condition should be verified to introduce the product in the market. Especially, vibration characteristics within operating speed range are very important in the aspect of structural stability as well as generator's electrical efficiency. This paper examines the vibration performance of a home made 1kW W/T Various data of the W/T model are acquired in real time using a remote vibration monitoring system installed in Daekwanryung test site. Vibration stability of the W/T structure is diagnosed based upon the data and the result is used to estimate the applicability of the W/T model.

• 산림경영
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• s.69
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• pp.10-11
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• 1991

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.2
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• pp.475-485
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• 1995

In this study, statistical analysis of fatigue data which had obtained from respective 24 fatigue crack, was examined for SiC whisker reinforced aluminium 6061 composite alloy (SiC$_{w}$/A16061) and aluminium 6061 alloy. SiC volume fraction in composite alloy is 25%. The analysis results stress intensity factor range and 0.1 mm fatigue crack initiation life for SiC$_{w}$/A16061 composite & A16061 matrix are the log-normal distribution. And regression analysis by linear model, exponential model and multiplicative model were performed to find out the relationship between fatigue crack growth rate(da/dN) and stress intensity for find out the relationship between fatigue crack growth rate(da/dN) and stress intensity factor range(.DELTA.K) in the SiC$_{w}$/A16061 composite and examine the applicability of Paris' equation to SiC$_{w}$A16061 composite. Also computer simulation was performed for fatigue life prediction of SiC$_{w}$/A16061 composite using the statistical results of this study.udy.

• Korean Journal of Materials Research
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• v.14 no.6
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• pp.394-398
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• 2004

A Ti47Al1.7W-3.7Zr alloy was oxidized between $900^{\circ}C$ and $1050^{\circ}C$, and the oxide scales formed were studied. The oxide scales consisted primarily of an outer$TiO_2$ layer, an intermediate $Al_2$$O_3$-rich layer, and an inner mixed ($TiO _2$ + $Al_2$$O_3$) layer. Besides $TiO_2$ and $Al_2$$O_3$, oxidation led to the formation of some $Ti_2$AlN and TiN. Both W and Zr were preferentially segregated below the intermediate $Al_2$$O_3$-rich layer. Tungsten in the oxide scale was present as $WO_3$ and ${Ti}_{x}$$W_{1-x}$, whereas zirconium as monoclic-$ZrO_2$ and tetragonal-$ZrO_2$.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.657-661
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• 1994

A method to analyse the concentration of mixture (AC/urea) and the concentration of urea or AC alone was developed. In this study, the decomposition of AC solution to ammonium bicarbonate was suppressed by using of 15% w/v ammonia as a solvent and the error of equilibrium point was maintained less than 1 %. Strong peaks at $1600cm^{-1}$ for urea and at $1405cm^{-1}$ for AC, corresponding to the N-H bending and symmetric carboxylate ion stretch were used to construct calibration graph and equations for the measurement of concentration. The errors of calculated concentration were ${\pm}0.1%$ w/v for AC and ${\pm}0.3%$ w/v for urea.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.9
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• pp.13-19
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• 1999

This paper describes a design of an 8-bit 100KSPS 1mW CMOS A/D Converter. Using a novel systematic offset cancellation technique, we reduce the systematic offset voltage of operational amplifiers. Further, a new Gain amplifier is proposed. The proposed A/D Converter is fabricated with a $0.6{\mu}m$ single-poly triple-metal n-well CMOS technology. INL and DNL is within ${\pm}1LSB$, and SNR is about 43dB at the sampling frequency of 100KHz. The power consumption is $980{\mu}W$ at +3V power supply.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3126-3132
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• 2023

To meet the increasing heating needs of the China Fusion Experimental Tokamak Reactor (CFETR), the output power in each Lower Hybrid Current Drive (LHCD) transmission line should be increased from 250 kW to 500 kW. Therefore, a new high-power water load must be developed for the 4.6 GHz 500 kW LHCD system. This paper aims to report the most recent research progress of the water load: aluminum nitride (AlN) ceramic is used as the media material to isolate the water and vacuum, and the radio frequency (RF) simulation results show that the return loss of the water load is less than -25dB at 4.6 GHz over a wide temperature range. Under 500 kW continuous wave (CW) operation, the maximum temperatures of the ceramic and water are separately 67 ℃ and 62 ℃, resulting in thermal deformation of the ceramic of approximately 0.003 mm. Moreover, the AlN water load was tested on the 4.6 GHz 250 kW high-power test bench and found to work well with low reflected power.