• Journal of Korean Academy of Nursing Administration
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• v.8 no.1
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• pp.107-121
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• 2002

The purpose of this study was to identify how nurse's image was perceived by nursing college students. The subjects included were 315 students experienced clinical practice during $20{\sim}22$ weeks and 134 students not with a total of 449 nursing students in Gwangju and Chonnam. The data were collected from November 21 to December 5, 2001 by the structured questionnaires. The research tool was measured by 30 items divided into four dimensions; traditional, professional, social and personal image of nurse. Cronbach $\alpha$ for the tool of nurse's image was 0.8960. The data were analysed by SPSS 8.0 for Windows program using frequency, percentage, mean, standard deviation, t-test, ANOVA and scheffe. The results of this study were as follows; 1. In the nurse's image related to general characteristics, there were significant differences for school graduation, applicative motivation, interpersonal relationship and image forming factor. 2. In the Image forming factors, nursing college students perceived the nurse's image by visiting hospital or admission(37.9%), watching TV(25.8) and others; nurses' appearance during clinical experience(16.3). 3. The mean score for nurse's image of clinical experience group (2.76$\pm$0.28) was lower than that of non-clinical experience group(2.89$\pm$0.31) in significance (t=4.319, p=0.000). 4. In the nurse's image according to clinical experience, there were significant differences for traditional, professional, social, personal image between two groups and the lower mean scores were found in the clinical experience group in all dimensions. The ranks of dimensions were professional image(3.08), traditional image(2.76), social image(2.65), the personal image(2.59) in clinical experience group, whereas professional image(3.21), traditional image(2.93), social image(2.75), personal image(2.71) for non-clinical experience group.5. The high score items of nurse's image were 'worthwhile work(3.48)', 'always working hard(3.30)', 'profession(3.17)', 'strong responsibility toward work(3.08)', 'have a high technical skill(3.05)' in clinical experience group and 'worthwhile work(3.69)', 'always working hard(3.28)', 'clean and decent(3.22)', 'profession(3.21)', 'have a bountiful professional knowledge(3.18)' in non-clinical experience group. 6. The highest mean score for nurse's image related to the image forming factors was 86.8 by novels or literature and the second highest was 84.3 by visiting hospital or admission. And others(mean=82.1)was the most negative nurse's image by clinical experience. In conclusion, nurse's image perceived by nursing college students will be the mirror of themselves. And clinical experience will be the important opportunity to form the professional image with white uniformed nurses in future. Therefore it is important for clinical nurses to play professional roles rightly so that nursing students could form positive nurse's image.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.31.4-32
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• 2011

The previous KRISS profilometer design used an aluminum profile structure to which a bar-type reference mirror subsystem and the measurement subsystem are mounted. The earlier design suffers from low stiffness as shown from the first resonance mode of 45.1 Hz. The improved mechanical design we describe in this study replaces the aluminium profile structure with a granite structure of $1340{\times}220{\times}230$ in dimension. The finite element analysis results for the revised design show 0.001 degree in probe contact angle variation. The first resonance mode was computed to 91.2 Hz that is much better than 45.1 Hz from the previous design. We describe the improved design, structural analysis results and how these results would satisfy the form accuracy requirement of 1 ${\mu}m$ PV.

• Korean Journal of Optics and Photonics
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• v.10 no.5
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• pp.364-368
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• 1999

We investigate the evaluation items of LSU (Laser Scanning Unit), such as beam size, f$\theta$ characteristics, linearity, skew and bow, optical power ratio between image height of 0mm and $\pm$108 mm, pitch error, Jitter and shift of printing position. Through the measurement of LSU using BSH (Beam Scan Head) installed on LMC (Linear Motion Controller) which moves linearly within the whole scanning range (-108 mm~+108 mm), we can ascertain plastic f$\theta$ lenses, which are manufactured by TVLP (Two-step Variable Low Pressure) molding method, to satisfy 600DPI(Dots Per Inch) performance.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.120-126
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• 2002

The needs of ultra-precisely machined parts are increasing more and more. But the experimental data required to ultra precision machining of nonferrous metal is insufficient. The behavior of cutting in micro cutting area is different from that of traditional cutting because of the size effect. Copper is widely used as optical parts such as LASER reflector's mirror and multimedia instrument. In experimental, after oxygen-free copper is machined by ultra precision machine with natural mono crystal diamond tool (NCD) and synthetic poly crystal diamond tool (PCD), we compared chip formation and tool's wear according to used tool. Also, we researched optimized cutting condition with the results measured according to cutting condition such as spindle speed, feed rate and depth of cut. As a result, the optimal working condition that makes good surface roughness is obtained. The surface roughness is good when spindle speed is above 80 m/min, and feed rate is small and depth of cut is above 0.5 ${\mu}{\textrm}{m}$. In cutting of klystron anode and cavity 3.2 nmRa of surface roughness is obtained.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.50-57
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• 2010

A high precision air bearing stage has been developed and calibrated. This linear-motor driven stage was designed to transport a glass or wafer with the X and Y following errors in nanometer regime. To achieve this level of precision, bar type mirrors were adopted for real time ${\Delta}X$ and ${\Delta}Y$ laser measurement and feedback control. With the laser wavelength variation and instability being kept minimized through strict environment control, the orthogonality of this type of control system becomes purely dependent upon the surface flatness, distortion, and assembly of the bar mirrors. Compensations for the bar mirror distortions and assembly have been performed using the self-calibration method. As a result, the orthogonality error of the stage was successfully decreased from $0.04^{\circ}$ to 2.48 arcsec.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1641-1644
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• 2005

현재의 인터넷과 같은 전자 통신망과 멀티미디어 시스템의 발달은 고속의 대용량 데이터 전송을 필요로 한다. 초고속 통신 시스템에서의 고속 데이터 전송은 주로 광섬유를 사용하는 광통신으로 이루어지고 있다. FTTH(Fiber To The Home)와 같은 광통신 시스템은 멀티미디어 커뮤니케이션을 위해 필요한 큰 데이터 전송률을 제공할 수 있기 때문에 더욱 더 중요성이 높아지고 있으며 이러한 광통신 시스템에서는 통신환경의 영향을 적게 받고 외부 조절이나 부품이 필요하지 않는 수신기 IC 의 개발이 요구되고 있다. 일반적으로 광통신 수신기에는 고속 동작에 적합한 특성을 가진 GaAs-MESFET 가 사용되고 있으나, 본 논문에서는 0.35um CMOS 2-poly 4-metal 공정을 이용하여 5Gbps 광수신기를 설계하였다. 설계된 수신기는 Preamplifier, Main amplifier, ABC 회로로 구성되어 있다. Transimpedance amplifier 형태의 Preamplifier 는 광검출기에 의해 생성된 전류 신호를 전압 신호로 변환한다. ABC 회로는 Peak_Hold 회로와 Bottom_Hold 회로로 구성되어 있다. 기존의 Peak_Hold 회로에서는 다이오드와 hold capacitor 를 이용하여 peak 값을 검출하도록 되어 있는데, 다이오드를 이용하는 경우 작은 입력 신호전압의 Peak 값을 검출하는 데 한계가 있다. 이러한 단점을 보완하고자 전류 거울형태의 Peak_Hold 회로를 설계하였다. 전류거울(current mirror)형태의 출력 신호의 duty error 를 줄이고 비트 에러율(Bit Error Rate)을 개선하는데 효과적이었다. 설계된 광수신기는 30dB 의 입력 dynamic range 와 입력 capacitance 3pF 에서 80MHz 의 대역폭을 가진다. 전력 소비량은 3.3V 전원 전압이 인가된 경우 약 150mW 정도이다.

• 보존과학연구
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• s.19
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• pp.109-132
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• 1998

According to excavation of Imdang site, these sites were excavated place to a various of sites from Early lron period to the Koryo Kingdom. Artifacts to be conserved were excavated from A, D and E district. Metal artifacts were excavated from D and E district and lacquer ware artifacts were excavated from Adistrict. Metal artifacts including lacquer ware iron sword, imitative bronze mirror, Osujen and bronze artifact with letter and so on. Bronze artifacts were covered with soil and rust and performed consolidation after passivation treatment with Benzotriazole solution. Also, iron artifacts performed desalting treatment with 0.1M sesquicarbonate solution. After desalinization, adhesive of these artifacts were processed with Araldite(rapid type) after consolidation with20%∼30% NAD-10 solution. Lacquer ware artifacts remained fragments of lacquer to be all corroded and soiled. Therefore these artifacts retained its original form. Fragments of lacquer joined with Caparol 1%∼3% solution and the soil of relics coated with PSNY 3%∼6% solution. There were many kinds of lacquer were. Lacquer ware artifacts presumed to a string instrument that provide important clues for lacquer ware research. As for lacquer fragments inquire, paints grain size were $2∼5\mum$ and conformed to vanished three times.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.178-185
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• 2007

Intermediate pentasil borosilicate zeolite-like materials have been crystallized by a novel method named steam-assisted conversion, which involves vapor-phase transport of water. Indeed, amorphous powders obtained by drying Na2O.SiO2.B2O3.TBA2O gels of various compositions using different boron sources are transformed into crystalline borosilicate zeolite belonging to pentasil family structure by contact with vapors of water under hydrothermal conditions. Using a variant of this method, a new material which has an intermediate structure of MFI/MEL in the ratio 90:10 was crystallized. The results show that steam and sufficiently high pH in the reacting hydrous solid are necessary for the crystallization to proceed. Characterization of the products shows some specific structural aspects which may have its unique catalytic properties. X-ray diffraction patterns of these microporous crystalline borosilicates are subjected to investigation, then, it is shown that the product structure has good crystallinity and is interpreted in terms of regular stacking of pentasil layers correlated by inversion centers (MFI structure) but interrupted by faults consisting of mirror-related layers (MEL structure). The products are also characterized by nitrogen adsorption at 77 K that shows higher microporous volume (0.160 cc/g) than that of pure MFI phase (0.119 cc/g). The obtained materials revealed high surface area (~600 m2/g). The infrared spectrum reveals the presence of an absorption band at 900.75 cm-1 indicating the incorporation of boron in tetrahedral sites in the silicate matrix of the crystalline phase.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.12
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• pp.91-96
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• 2011

In this paper, a low-power direct-conversion transmitter based on current-mode operation, which satisfies the IEEE 802.15.4 standard, is proposed and implemented in a $0.13{\mu}m$ CMOS technology. The proposed transmitter consists of DACs, LPFs, variable gain I/Q up-conversion mixer, a divide-by-two circuit with LO buffer, and a drive amplifier. By combining DAC, LPF, and variable gain I/Q up-conversion mixer with a simple current mirror configuration, the transmitter's power consumption is reduced and its linearity is improved. The drive amplifier is a cascode amplifier with gain controls and the 2.4GHz I/Q differential LO signals are generated by a divide-by-two current-mode-logic (CML) circuit with an external 4.8GHz input signal. The implemented transmitter has 30dB of gain control range, 0dBm of maximum transmit output power, 33dBc of local oscillator leakage, and 40dBc of the transmit third harmonic component. The transmitter dissipates 10.2mW from a 1.2V supply and the die area of the transmitter is $1.76mm{\times}1.26mm$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3614-3621
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• 2009

In this paper, A CMOS low-voltage current mode integrator is designed. The designed current-mode integrator is based on linear cascode circuit that is newly proposed in this paper. When it is compared with gain(43.7dB) and unity gain frequency(15.2MHz) of the typical current-mirror type current-mode integrator, the proposed linear cascode current-mode integrator achieves high current gain(47.8dB) and unity gain frequency(27.8MHz). And a 5th Chebyshev current-mode filter with 7.03MHz cutoff frequency is designed. The designed all circuits are simulated by HSPICE using 1.8V-$0.18{\mu}m$ CMOS technology.