• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.1383-1388
• /
• 2015

Proportional integral derivative (PID) control is one of the conventional control strategies. Industrial PID control has many options, tools, and parameters for dealing with the wide spectrum of difficulties and opportunities in manufacturing plants. It has a simple control structure that is easy to understand and relatively easy to tune. Injection mold is warming up to the idea of cycling the tool surface temperature during the molding cycle rather than keeping it constant. This “heating and cooling” process has rapidly gained popularity abroad. However, it has discovered that raising the mold wall temperature above the resin’s glass-transition or crystalline melting temperature during the filling stage is followed by rapid cooling and improved product performance in applications from automotive to packaging to optics. In previous studies, optimization methods were mainly selected on the basis of the subjective experience. Appropriate techniques are necessary to optimize the cooling channels for the injection mold. In this study, a digital signal processor (DSP)-based PID control system is applied to injection molding machines. The main aim of this study is to optimize the control of the proposed structure, including a digital PID control method with a DSP chip in the injection molding machine.

• Structural Engineering and Mechanics
• /
• v.44 no.6
• /
• pp.753-762
• /
• 2012

The ratcheting characteristics of cylindrical shell under cyclic axial loading are investigated. The specimens are subjected to stress-controlled cycling with non-zero mean stress, which causes the accumulation of plastic strain or ratcheting behavior in continuous cycles. Also, cylindrical shell shows softening behavior under symmetric axial strain-controlled loading and due to the localized buckling, which occurs in the compressive stress-strain curve of the shell; it has more residual plastic strain in comparison to the tensile stress-strain hysteresis curve. The numerical analysis was carried out by ABAQUS software using hardening models. The nonlinear isotropic/kinematic hardening model accurately simulates the ratcheting behavior of shell. Although hardening models are incapable of simulating the softening behavior of the shell, this model analyzes the softening behavior well. Moreover, the model calculates the residual plastic strain close to the experimental data. Experimental tests were performed using an INSTRON 8802 servo-hydraulic machine. Simulations show good agreement between numerical and experimental results. The results reveal that the rate of plastic strain accumulation increases for the first few cycles and then reduces in the subsequent cycles. This reduction is more rapid for numerical results in comparison to experiments.

• Korean Journal of Materials Research
• /
• v.8 no.4
• /
• pp.323-327
• /
• 1998

All solid state lithium based rechargeable batteries were fabricated in a cell structure of Li/PEO-$LiCIO_4$-PC /$LIMn_2O_4$$LIMn_2O_4$ thin films were prepared by RF magnetron sputtering and the spinel structure could be obtained by Rapid Thermal Annealing (RT A) process at the temperature of around 750$750^{\circ}C$ . Room temperature cycling of this cell showed a nearly constant cell potential of 4 V( us. Li) and good reversibility.

• Journal of Electrochemical Science and Technology
• /
• v.14 no.3
• /
• pp.272-282
• /
• 2023

Ni-rich layered oxides cathode has recently gained attention as an advanced cathode material due to their applicable energy density. However, as the Ni component in the layered site is increased, the high reactivity of Ni⁴⁺ results in parasitic reaction associated with decomposing electrolyte, which leads to a rapid decreasing the lifespan of the cell. The electrolyte additive triallyl borate (TAB) improves interfacial stability, leading to a stable cathode-electrolyte interphase (CEI) layer on the LNCM83 cathode. A multi-functionalized TAB additive can produce a uniformly distributed CEI layer via electrochemical oxidation, which implies an increase in long-term cycling performance. After 100 cycles at elevated temperature, the cell tested by 0.75 TAB retained 88.3% of its retention ratio, whereas the cell performed by TAB-free electrolyte retained 64.1% of its retention. Once the TAB additive formed CEI layers on the LNCM83 cathode, it inhibited the decomposition of carbonate-based solvents species in addition to the dissolution of transition metal components from the cathode. The addition of TAB to LNCM83 cathode material is believed to be a promising way to increase the electrochemical performance.

• Applied Chemistry for Engineering
• /
• v.25 no.1
• /
• pp.1-13
• /
• 2014

Lithium ion batteries (LIBs) are the state-of-the-art technology among electrochemical energy storage and conversion cells, and are still considered the most attractive class of battery in the future due to their high specific energy density, high efficiency, and long cycle life. Rapid development of power-hungry commercial electronics and large-scale energy storage applications (e.g. off-peak electrical energy storage), however, requires novel anode materials that have higher energy densities to replace conventional graphite electrodes. Germanium (Ge) and silicon (Si) are thought to be ideal prospect candidates for next generation LIB anodes due to their extremely high theoretical energy capacities. For instance, Ge offers relatively lower volume change during cycling, better Li insertion/extraction kinetics, and higher electronic conductivity than Si. In this focused review, we briefly describe the basic concepts of LIBs and then look at the characteristics of ideal anode materials that can provide greatly improved electrochemical performance, including high capacity, better cycling behavior, and rate capability. We then discuss how, in the future, Ge anode materials (Ge and Ge oxides, Ge-carbon composites, and other Ge-based composites) could increase the capacity of today's Li batteries. In recent years, considerable efforts have been made to fulfill the requirements of excellent anode materials, especially using these materials at the nanoscale. This article shall serve as a handy reference, as well as starting point, for future research related to high capacity LIB anodes, especially based on semiconductor Ge and Si.

• Korean Journal of Remote Sensing
• /
• v.39 no.5_3
• /
• pp.1043-1060
• /
• 2023

An acceleration of climate change in recent years has led to increased attention towards 'blue carbon' which refers to the carbon captured by the ocean. However, our comprehension of marine ecosystems is still incomplete. This study classified and analyzed global marine eco-provinces using k-means clustering considering carbon cycling. We utilized five input variables during the past 20 years (2001-2020): Carbon-based Productivity Model (CbPM) Net Primary Production (NPP), particulate inorganic and organic carbon (PIC and POC), sea surface salinity (SSS), and sea surface temperature (SST). A total of nine eco-provinces were classified through an optimization process, and the spatial distribution and environmental characteristics of each province were analyzed. Among them, five provinces showed characteristics of open oceans, while four provinces reflected characteristics of coastal and high-latitude regions. Furthermore, a qualitative comparison was conducted with previous studies regarding marine ecological zones to provide a detailed analysis of the features of nine eco-provinces considering carbon cycling. Finally, we examined the changes in nine eco-provinces for four periods in the past (2001-2005, 2006-2010, 2011-2015, and 2016-2020). Rapid changes in coastal ecosystems were observed, and especially, significant decreases in the eco-provinces having higher productivity by large freshwater inflow were identified. Our findings can serve as valuable reference material for marine ecosystem classification and coastal management, with consideration of carbon cycling and ongoing climate changes. The findings can also be employed in the development of guidelines for the systematic management of vulnerable coastal regions to climate change.

• Journal of Korean Ophthalmic Optics Society
• /
• v.7 no.2
• /
• pp.163-167
• /
• 2002

Improved optical switching property of electrochromic nickel hydroxide/nickel glass thin film is reported. Nickel metal film was deposited on glass by e-beam evaporation before following electrochemical redox cycling to form nickel hydroxide for electrochromic activation. Without ITO (indium tin oxide) layer as electrical conductor, this electrode showed more rapid coloration rate than nickel hydroxide film on ITO substrate in the change of the electric voltage and optical transmittance. XPS analysis confirmed the existence of ultra-thin nickel metal layer (${\sim}10{\AA}$) between electrochemically grown nickel hydroxide and the glass substrate. It is concluded that the remained nickel metal nano-layer attribute to the conduction layer and the enhanced response time.

• Korean Journal of Biological Psychiatry
• /
• v.1 no.1
• /
• pp.40-59
• /
• 1994

The introduction of lithium salts for the treatment of mood disorder by Code in 1949 was a major therapeutic breakthrough. Yet it is far from the universal therpeutic agent in the treatment of mood disorders. Indeed, some acutely manic patients do not respond adeqately to lithium and some individuals experience breakthrough affective episodes during lithium maintenance. In the last decode, it has become c1ear that a significant number of patients with more highly recurrent disorders may require alternative or enhanced forms of prophylactic treatment. For these reasons, a variety of other drugs hove been employed for the treatment and prophylaxis of mood disorders. Efforts to develop new pharmacologic strategies for mood disorder hove included a diverse array of medications, ranging from potent benzodiazepines to novel neuroleptics and from anticonvulsants to calcium channel blockers. The anticonvulsants appear particularly useful in cases of dysphoric mania and rapid cycling state, subforms of bipolar disorder that respond quite poorly to conventional treatments. Among all of these new pharmacologic strategy, carbamazepine and sodium valproate have received the broadest clinical applications as maintenance therapies. The data documenting the short-term antimanic effectiveness of the calcium channel blocker verapamil and benzodiazepins such as clonazepam and lorazepam appear also promising. A number of other theoretically interesting, as well as clinically relevant therapies, which are not presently employed routinly, hove also been studied, including 2 blocker clonidine, atypical antipsychotic clozapine, cholinomimetics, 5-HT enhancers, thyroid and magnesium preparations. Now prophylaxis in mood disorder remains a considerable therapeutic challenge. Controlled testing of the prophylactic efficacy of compounds such as carbamazepine, valproic acid, and the calcium channel blockers represent important next step in the clinical trials for mood disorder.

• Journal of Soil and Groundwater Environment
• /
• v.22 no.3
• /
• pp.10-17
• /
• 2017

In this study, the evolution and origin of major dissolved constituents of crystalline bedrock groundwater in a coastal area were evaluated using multivariate statistical and groundwater quality analyses. The groundwater types mostly belonged to the $Na(Ca)-HCO_3$ and $Ca-HCO_3$ types, indicating the effect of cation exchange. Stable isotopes of water showed two areas divided by first and secondary evaporative effects, indicating a pattern of rapid hydrological cycling. Saturation indices of minerals showed undersaturation states. Thus, the degree of evolution of groundwater is suggested as in the low to intermediate stage, based on field and laboratory analytical conditions. According to the principal component analysis (PCA) results, the chemical components of EC, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $HCO_3{^-}$, $SO{_4}^{2-}$ (PCA 1), $F^-$ (PCA 3), $SiO_2$ (PCA 4), and $Fe^{2+}$ (PCA 5) are derived from various water-rock interactions. However, $NO_3{^-}$, $Na^+$, and $Cl^-$ (PCA 2) represented the chemical characteristics of both anthropogenic sources and natural sea spray.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1997.04a
• /
• pp.109-109
• /
• 1997

Inhibitory effect on DNA topoisomerase-I, rate of glutathione conjugation and cytotoxicity of naphthoquinone derivatives were correlated. During 5 min exposure of the derivatives to glutathione (GSH), it was found that 14% of 5,8-dimethoxy-1,4-naphthoquinone(DMNQ) was converted into a GSH-conjugate, whereas 5,8-dihydroxy-1,4-naphthoquinone(DHNQ) did not interact with GSH, implying that DMNQ exerted higher electrophilicity than DHNQ. However, DHNQ (IC$\_$50/, 0.15 ${\mu}$M) showed stronger cytotoxicity in L1210 cells than DMNQ(IC$\_$50/, 0.45 ${\mu}$M). The stronger cytotoxicity of DHNQ, compared to DMNQ, could be ascribed to more rapid redox cycling. Both naphthoquinones (IC$\_$50/, 60-65 ${\mu}$M) exhibiting about the same inhibitory effect on DNA topoisomerase-I were more potent than 1,4-naphthoquinone(1,4-NQ, IC$\_$50/, 134 ${\mu}$M). Thus, 5,8-oxy groups in the structure seem to be important for the inhibition of the enzyme. DMNQ showed a broader dose range while maintaining a good antitumor activity against S-180 fluid tumor. For these reasons, DMNQ was taken as useful pharmacophore for structural modification. Introduction of 1-hydroxyalkyl groups at C-2 of DMNQ lowered all of the activities mentioned above, while acetylation of 1-hydroxyalkyl moiety enhanced the activities by 4-5 times. Introduction of the same side chains at C-6 exhibited stronger activities than 2-substituted ones. Based on these results it was suggested that the quinonoid moiety in 6-substituted DMNQ was more exposed to cellular nucleophiles such as DNA, thiols of enzymes and so on. The synthesis of DHNQ or DMNQ derivatives are going on, and the corelationship between structure-activity will be discussed.