• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.15 no.4
• /
• pp.321-332
• /
• 2017

In order to build a general model of a high-throughput uranium electrorefining process according to the electrode configuration, numerical analysis was conducted using the COMSOL Multiphysics V5.3 electrodeposition module with Ordinary Differential Equation (ODE) interfaces. The generated model was validated by comparing a current density-potential curve according to the distance between the anode and cathode and the electrode array, using a lab-scale (1kg U/day) multi-electrode electrorefiner made by the Korea Atomic Energy Research Institute (KAERI). The operating temperature was $500^{\circ}C$ and LiCl-KCl eutectic with 3.5wt% $UCl_3$ was used for molten salt. The efficiency of the uranium electrorefining apparatus was improved by lowering the cell potential as the distance between the electrodes decreased and the anode/cathode area ratio increased. This approach will be useful for constructing database for safety design of high throughput spent nuclear fuel electrorefiners.

• Korean Journal of Weed Science
• /
• v.6 no.1
• /
• pp.1-6
• /
• 1986

The growth, development, and morphological characteristics of Echinochtoa colons (L.) Link were determined through one life cycle. E. colons emerged 2 to 3 days after seeding (DAS) and reached the two leaf stage by 8 DAS. During the early growth stages, root length was greater than plant height, but the relationship was reversed from 4 weeks after seeding (WAS). Tillering started from the third leaf of the main culm as the sixth leaf on the main calm emerged. The unfolding of the leaves and tillering followed a regular pattern during the vegetative growth period. This resulted in the production of 19 tillers (5 primary, 12 secondary, 1 tertiary, and I nodal) at the 14-leaf stage. Shoot-root weight ratio was highest just before panicle initiation. The second spike from the top of the panicle was the shortest and produced the fewest seeds. Thereafter, spike length and the number of seeds per spike generally increased, the lower the position of the spike on the panicle. Seeds on the lower spikes weighed less and had lower germination ability than those from the upper spikes. Adventitious roots arose from the leaf sheath bases of a flowering stalk. The ability to produce adventitious roots was greater in a younger stalls than in an older stalk.

• Clinical and Experimental Reproductive Medicine
• /
• v.18 no.2
• /
• pp.201-208
• /
• 1991

Recently the application of gonadotropin-releasing hormone (GnRH) agonist to superovulation in previous poor responders has resulted in the improved outcomes after in vitro fertilization (IVF) outcome. However, poor responders with poor estradiol $(E_2)$ rise or single dominant follicle are a particularly challenging group. Recent reports have also shown that patients with higher basal serum follicle stimulating hormone (FSH) level, result in poorer ovarian response and lower pregnancy rate. Analysis of the differences of superovulation outcomes according to the different protocols of GnRH agonist, long (L, n = 18) and short (S, n = 16) protocols, in patients with high basal FSH levels (>20mIU/ml) were undertaken at Seoul National University Hospital from June to October 1990. The administration of GnRH agonist was begun on day 21 of the cycle in long protocol, and on day 2 in short protocol. Ages of patients and husbands, basal FSH and luteinizing hormone (LH) levels and FSH/LH ratio did not differ significantly. Types and causes of infertility were evenly distributed. Whereas the duration of stimulation and the amounts of gonadotropins administered were significantly reduced in short protocol, the numbers of oocytes retrieved and cleaved, the cleavage rate and the number of embryos transferred were higher in long protocol without statistical signifieance. The pregnancy rate per ET was 16.7% (2/12) in short protocol, and 17.6% (3/17) in long protocol. These data suggest that both protocols result in the similar superovulation outcomes in patients with higher basal serum FSH levels.

• Korean Journal of Ichthyology
• /
• v.17 no.3
• /
• pp.195-204
• /
• 2005

The population ecology of Rhinogobius brunneus was investigated on, tributaries of the Bukhan River from May 2003 to June 2005. The habitat was mostly a rapids area with pebbles and cobles in the lower part of the stream. The cohabitation fishes were Zacco platypus, Zacco temmincki, Microphysogobio yaluensis and Iksookimia koreensis. The males and females become sexually mature after one year. Spawning season was from May to June with water temperatures in the range $22{\sim}25^{\circ}C$. The prosperous period was from late May to early June. The average number of eggs in the ovary was $989{\pm}511$ (range, 151~2,209). The year-round sex ratio of female to male was 1 : 0.90. The total length in this population indicated that the below-40 mm group is one year old, 40~52 mm group is two years old, 52~65 mm group is three years old, and the longer-than-65 mm group is over four years old. There were no differences in total length distribution between the males and females. Nests were built up at a water depth of $13.7{\pm}5.8$ (5~31) cm and a current velocity of $9.6{\pm}4.8$ (10~19) cm/sec. Brood size (egg number) of the parental male was $1,974{\pm}1810$ (egg number = $95.022_{TL}-3507$, $r^2=0.3591$, N = 33). Newly hatched larvae that drifted downstream to the lake returned to the stream during late June to August; the smallest size in this population was 20 mm in total length.

• Korean Chemical Engineering Research
• /
• v.46 no.2
• /
• pp.414-422
• /
• 2008

Adsorption experiments for $H_2$, $CH_4$, CO, $CO_2$ on activated carbon and zeolite 5A were performed by static volumetric method. A 4-bed pressure swing adsorption (PSA) process was to study separation of hydrogen from multi-component mixture gases ($H_2$ 72.2%, $CH_4$ 4.06%, CO 2.03%, $CO_2$ 21.6%). Dual-site langmuir (DSL) isotherm showed good or fair agreement with the experimental results. The optimum height of activated carbon layer was 55 cm with breakthrough results on the packing ratio of activated carbon to zeolite 5A. In PSA process, the effects of the process parameters such as total cycle time ($T_c$), ${\Delta}P$ at the provide purge step and adsorption pressure on the PSA performance were studied experimentally and theoretically.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.993-994
• /
• 2008

Electrochromic (EC) devices are capable of reversibly changing their optical properties upon charge injection and extraction induced by the external voltage. The characteristics of the EC device, such as low power consumption, high coloration efficiency, and memory effects under open circuit status, make them suitable for use in a variety of applications including smart windows and electronic papers. Coloration due to reduction or oxidation of redox chromophores can be used for EC devices (e-paper), but the switching time is slow (second level). Recently, with increasing demand for the low cost, lightweight flat panel display with paper-like readability (electronic paper), an EC display technology based on dye-modified $TiO_2$ nanoparticle electrode was developed. A well known organic dye molecule, viologen, was adsorbed on the surface of a mesoporous $TiO_2$ nanoparticle film to form the EC electrode. On the other hand, ZnO is a wide bandgap II-VI semiconductor which has been applied in many fields such as UV lasers, field effect transistors and transparent conductors. The bandgap of the bulk ZnO is about 3.37 eV, which is close to that of the $TiO_2$ (3.4 eV). As a traditional transparent conductor, ZnO has excellent electron transport properties, even in ZnO nanoparticle films. In the past few years, one-dimension (1D) nanostructures of ZnO have attracted extensive research interest. In particular, 1D ZnO nanowires renders much better electron transportation capability by providing a direct conduction path for electron transport and greatly reducing the number of grain boundaries. These unique advantages make ZnO nanowires a promising matrix electrode for EC dye molecule loading. ZnO nanowires grow vertically from the substrate and form a dense array (Fig. 1). The ZnO nanowires show regular hexagonal cross section and the average diameter of the ZnO nanowires is about 100 nm. The cross-section image of the ZnO nanowires array (Fig. 1) indicates that the length of the ZnO nanowires is about $6\;{\mu}m$. From one on/off cycle of the ZnO EC cell (Fig. 2). We can see that, the switching time of a ZnO nanowire electrode EC cell with an active area of $1\;{\times}\;1\;cm^2$ is 170 ms and 142 ms for coloration and bleaching, respectively. The coloration and bleaching time is faster compared to the $TiO_2$ mesoporous EC devices with both coloration and bleaching time of about 250 ms for a device with an active area of $2.5\;cm^2$. With further optimization, it is possible that the response time can reach ten(s) of millisecond, i.e. capable of displaying video. Fig. 3 shows a prototype with two different transmittance states. It can be seen that good contrast was obtained. The retention was at least a few hours for these prototypes. Being an oxide, ZnO is oxidation resistant, i.e. it is more durable for field emission cathode. ZnO nanotetropods were also applied to realize the first prototype triode field emission device, making use of scattered surface-conduction electrons for field emission (Fig. 4). The device has a high efficiency (field emitted electron to total electron ratio) of about 60%. With this high efficiency, we were able to fabricate some prototype displays (Fig. 5 showing some alphanumerical symbols). ZnO tetrapods have four legs, which guarantees that there is one leg always pointing upward, even using screen printing method to fabricate the cathode.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.7
• /
• pp.771-777
• /
• 2008

In this paper, a frequency doubler using modified time-delay technique is proposed. A voltage controlled delay line (VCDL) in the proposed frequency doubler compensates the group delay time mismatching between input and delayed signal. With the group delay time matching and waveform shaping using the adjustable Schmitt triggers, the unwanted fundamental component($f_0$) and the higher order harmonics such as third and fourth are diminished excellently. In result, only the doubled frequency component($2f_0$) appears dominantly at the output port. The frequency doubler is designed at 1.15 GHz of $f_0$ and fabricated with TSMC $0.18\;{\mu}m$ CMOS process. The measured output power at $2f_0$ is 2.67 dBm when the input power is 0 dBm. The obtained suppression ratio of $f_0,\;3f_0$, and $4f_0$ to $2f_0$ are 43.65, 38.65 and 35.59 dB, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.2
• /
• pp.145-152
• /
• 2010

This study evaluated the fatigue degradation in a SUS316L specimen using the nonlinear ultrasonic method. The nonlinearity of the ultrasonic wave was estimated by a relative nonlinear parameter defined as the ratio of the amplitudes for the fundamental wave to the second harmonic wave. In the experiment, a measurement system with contact transducers was constructed; reliable measurements were assured by keeping measurement conditions consistent and reducing extra harmonics generated in the measurement system. Two types of SUS316L specimen were used in experiments; a rotating bar fatigue specimen and a tensile fatigue specimen. The fatigue condition used was high cycle fatigue. The former specimen had a cylindrical shape and was used to observe the change in the nonlinear parameter after fatigue accumulation in a specimen. The latter was a plate-shaped specimen and was used to confirm the change in the nonlinear parameter at the position where the fatigue stress was concentrated. The measured nonlinear parameter showed a strong correlation to the damage level in both fatigue tests.

• Applied Chemistry for Engineering
• /
• v.26 no.6
• /
• pp.674-680
• /
• 2015

A solvent-soluble polyimide (PI) polymeric binder was synthesized by a two-step reaction for silicon (Si) anodes for lithium-ion batteries. Polyamic acid was first prepared through ring opening between two monomers, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCDA) and 4,4-oxydianiline (ODA), followed by condensation reaction. Using the synthesized PI polymeric binder (molecular weight = ~10,945), the coating slurry was then prepared and Si anode was fabricated. For the control system, Si anode based on polyvinylidene fluoride (PVDF, molecular weight = ~350,000) having the same constituent ratio was prepared. During precycling, PI polymeric binder revealed much improved discharge capacity ($2,167mAh\;g^{-1}$) compared to that of using PVDF polymeric binder ($1,740mAh\;g^{-1}$), while the Coulombic efficiency of two systems were similar. PI polymeric binder improved the cycle retention ability during cycles compared to that of using PVDF, which is attributed to an improved adhesion property inside Si anode diminishing the dimensional stress during Si volume changes. The adhesion property of each polymeric binder in Si anode was confirmed by surface and interfacial cutting analysis system (SAICAS) (Si anode based on PI polymeric binder = $0.217kN\;m^{-1}$ and Si anode based on PVDF polymeric binder = $0.185kN\;m^{-1}$).

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.17
• /
• pp.7297-7301
• /
• 2014

Objective: To explore the radiosensitization effect of overexpression of silent information regulator 6 (SIRT6) on A549 non-small cell lung cancer (NSCLC) cells. Methods: Adenovirus vector Ad-SIRT6 causing overexpression of SIRT6 was established. Western blotting and MTT assay were adopted to detect the level of SIRT6 protein and the inhibitory rate of A549 cell proliferation after different concentrations of adenovirus transduction (0, 25, 100, 200, and 400 pfu/cell) for 24 h. Control group, Ad-null group and Ad-SIRT6 group were designed in this experiment and virus concentration of the latter two groups was 200 pfu/cell. Colony formation assays were employed to test survival fraction (SF) of the 3 groups after 0, 2, 4, 6, 8, 10 X-ray irradiation. Flow cytometry was used to detect the status of cell cycle of 3 groups after 48 h of 4Gy X-ray irradiation and Western blotting was used to determine the expression of apoptosis-related genes of 3 groups after 48 h of 4GyX-ray irradiation. Results: In the range of 25~400 pfu/cell, the inhibitory rate of A549 cell proliferation increased as adenovirus concentration raised. The inhibitory rates under the concentrations of 0, 25, 100, 200, and 400 pfu/cell were 0%, $4.23{\pm}0.34%$, $12.7{\pm}2.57%$, $22.6{\pm}3.38%$, $32.2{\pm}3.22%$, $38.7{\pm}4.09%$ and $47.8{\pm}5.58%$ and there were significantly differences among groups (P<0.05). SF in Ad-SIRT6 group was lower than Ad-null and control groups after 4~10Gy X-ray irradiation (P<0.05) and the sensitization enhancement ratio (SER) was 1.35 when compared with control group. Moreover, after 48 h of 4Gy X-ray irradiation, there appeared a significant increase in G1-phase cell proportion, upregulated expression of the level of apoptosis-promoting genes (Bax and Cleaved caspase-3), but a obvious decline in S-phase and G2-phase cell proportion and a significant decrease of the level of apoptosis-inhibiting gene (Bal-2) in the Ad-SIRT6 group (P<0.05). Conclusion: The over-expression of adenovirus-mediated SIRT6, which has radiosensitization effect on A549 cells of NSCLC, can inhibit the proliferation of A549 cells and cause G0/G1 phase retardation as well as induce apoptosis of cells.