Sodium A Zeolite의 흡착특성에 관한 연구

전윤,김숭평 조선대학교 생산기술연구소 1984 生産技術硏究 Vol.6 No.2

The adsorption isotherms of oxygen on the natural zeolite were obtained at the temperature of liquid oxygen and analysed by utilizing Langmuirs and Dubinin Astakhovs equation. The conclusion is that there are two types of adsorption site and effective micropore volume obtained from the intercepts taken at p/p_(o)=1 by extrapolation of the linear parts of isotherms of the zeolites have a maximum value at about 35 unit cell number, but real volumes of the solids increase linearly with decreasing unit cell number until the corruption of zeoite crystal structure is reached. The characteristic energies of adsorption on the zeolite increase linearly with increasing unit cell number.

액정폴리에스테르와 poly(ethylene 2,6-naphthalate)의 블렌드

전윤 조선대학교 생산기술연구소 1996 生産技術硏究 Vol.18 No.2

A new thermotropic liquid crystalline polyester(TLCP) was synthesized and melt blended with PEN for the application of in situ composite. The TLCP showed nematic behavior in melt with an m.p. of 211℃. The glass transition temperature(Tg) of the PEN in the blends decreased as the content of TLCP increased. and the TLCP acted as a nucleating agent for the matrix polymers. The TLCP domains in the blend fibers were well dispersed with its size of 0.3㎛, and the skin-core effect was observed in the 20% TLCP/PEN blend fibers.

氣一固系 充塡 流動層에 關한 分級硏究

田允 조선대학교 생산기술연구소 1981 生産技術硏究 Vol.1981 No.-

The segregation of a larger and smaller particles in a gas-solid fluidized bed packed with glass ball was studied with glass particle. The overall degree of segregation was difined as the difference in the weight percent of smaller particles between the samples of top and bottom of the bed, while the local degree of segregation was difined as the local weight percent of the smaller particles. The experiment was started afer putting larger particles on the top of the smaller one. The local and the overall degree of segregations as a function of bed height were obtained for the various gas flow rates and sizes. As a result, the glass ball packed fluidized bed could be effectively used for the particle segregation. Also, the higher bed height gave better segregation and the segregation was most effective at 2 times gas flow rate of the minimum fluidization.

PET와 열방성 액정 코폴리에스테르의 블렌드

전윤 조선대학교 생산기술연구소 1996 生産技術硏究 Vol.18 No.1

Blends of a thermotropic liquid crystalline polyester, poly(PET/TR4) with poly (ethylene terephthalate)(PET) were prepared by precipitation from a mixed solvents. followed by drying and compression molding to produce a polymer sheet. Thermal, morphological and physical properties of the blends were examined by differential scanning calorimetry. optical microscopy and scanning electron microscopy. On the blend containing 1% of the TLCP, interfacial adhesion between the TLCP and the pure PET appeared excellent. The TLCP also acts as a good nucleating agent and improves crystal growth rate in the blends.

증류탑에 있어서의 미량성분의 단효율에 관한 연구

田允 조선대학교 생산기술연구소 1981 生産技術硏究 Vol.1981 No.-

The plate efficiency of a minor component is requisite to predict the behavior of that component in distillation. By uae of an older show-type column, continuous rectification of an azeotropic mixture of isopropanol and water containing a minute amount of furfural was carried out under various conditions. The concentrations of the minor component in distillate and bottoms were obtained. An equation describing the ratio of the concentration of a minor component in distillate to that in bottoms was derived. The Murphree vopor efficiencies were determined so as to fit the calculated ratios to the experiment ones. Plotting efficencies against vapor rate shows that efficiencies are within the limit of 0.7∼0.8 at vapor rate higher than about 35g/㎠hr. When the vopor rate becomes lower than that, however, the data are scattered. In the system described in this paper, the value of efficiency of the minor component at higher vapor rates is comparable to that obtained for a major component by the conventional method.

Disiloxane spacer를 갖는 액정 중합체의 합성 및 특성 연구

전윤,신성의,송연호,권규혁,김선,신대윤,최형일,최재곤 조선대학교 생산기술연구소 1983 生産技術硏究 Vol.1983 No.-

Two closely related copolymers that contain a di (oxyphenyl) terephthalate or a hydroquinone ring as a rnesogenic unit interconnected by a decamethylene and a disiloxane as flexible spacers in the main chain were synthesized and characterized for their mesogenic properties. These two polymers showed nematic mesogenic behavior and the phase transitions from solid to nematic phases and from nematic to isotropic were reversible, that is, antiotropic. The effect of spacers on the mesogenic unit on the stability of the mesophase or on the orientational order of polymer units in the mesophase could be rationalized on the bases of observed thermodynamic data.

키토산 미소구체가 약물방출에 미치는 영향

전윤,차월석,권규혁,이동병 조선대학교 생산기술연구소 2000 生産技術硏究 Vol.22 No.1

In this study, we examined about effectives of the drug release by used glutaraldehyde amount and molecular weight varieties of chitosan in DDS. The release experiments of chitosan microspheres containing norfloxacin were operated in the phosphate buffer solutions of pH 7.4 and 37℃, and its results were as follows. In the linearly release time of drug, chitosan microspheres (Mw 190,000) of used glutaraldehyde 1 mL and 2 mL were 45 and 64 days, and chitosan microspheres (Mw 350,000) of used glutaralhyde 1 mL and 2 mL were 60 and 80 days relatively. These results showed more effective drug releases in the increments of molecular weight and glutaraldehyde In short, the formulation allows chitosan microspheres to suppress the burst effect of the drug release mechanism, which led to the controlled release pattern and microspheres

半導體 中의 轉位運動

全潤漢 金烏工科大學校 1981 論文集 Vol.2 No.-

To search out the common characteristics of the experimental results on th dislocation mobilities in semiconductor crystals, many previous works are reviewed. As a result we conclude that the dislocation motions are thermally activated motion which depends on the applied stress, and the dislocation velocities depend on the its electrical properties(the type of doping and concentration). Mostly in n-type semiconductors, the dislocations move faster than in p-type.

不純物이 過量 注入된 실리콘 單結晶의 高溫微小硬度

全潤漢 金烏工科大學校 1986 論文集 Vol.7 No.-

The indentation microhardness are measured for heavily doped n- and p-type silicon single crystals over a wide range of temperature. It is shown that the deformation process to produce an indentation is not influenced by the impurity type. The experimental results are compared with Harada et al.

모드록킹된 Ti:Sapphire 레이저로부터 단일 펄스 추출

전윤한,김규욱,추한태 金烏工科大學校 産業技術開發硏究院 1998 産業技術開發硏究 Vol.14 No.-

We have performed the active mode-locking of a Ti;sapphire laser by using an acousto-optic modulator in a Z-type laser cavity pumped by Ar-ion laser and extracted a single pulse by using a pockels cell and a polarization beam splitter. The maximum average output power of the mode-locked Ti;sapphire laser was 500 mW with a pulse repetition rate of 86.6 MHz at a pump power of 5.5W. The linewidth(FWHM) of an extracted single pulse laser spectrum was 5 nm at the center wavelength of 811nm. The single pulse width with a pulse repetition rate of 1 Hz was 0.14 ps. The energy per pulse and the pulse peak power was 6nJ and 43 kW respectively.