• Journal of the Korean Institute of Telematics and Electronics
• /
• v.13 no.6
• /
• pp.7-11
• /
• 1976

A voltage-stable negative resistance circuit with operational amplifier is proposed, and circuit analysis is given all the input voltage range. The behavior of the v-i characteristics in the nogative resistance region is devided into two causes, and top points in the input v-i characteristics of the circuit is analyzed with them. Experimental results of the v-i characteristics of the proposed circuit has a good linearity in the negative region with negative resistance, -86$\Omega$~-833$\Omega$ for the input voltage, $\pm$ 1~$\pm$ 5 colts. The v-i characteristics of the circuit in all the input voltage range is discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.1
• /
• pp.59-62
• /
• 2017

CNT (carbon nanotube) resistors with low resistance and negative TCR (temperature coefficient of resistance) were fabricated with yarned CNT (carbon nanotube) fibers. The CNT fibers were prepared by yarning CNTs grown on the silicone substrate by CVD (chemical vapor deposition) method. The CNT resistors were fabricated by winding CNT fibers on the surface of ceramic rod. Both metal terminals were connected with the CNT fiber wound on the ceramic rod. We measured electrical resistance and thermal stability with the number of CNT fibers wound. The CNT resistor system shows linearly decreased resistance with the number of CNTs wound on the ceramic rod and saturated at 20 strands. The CNT resistor system has negative TCR between $-1,000{\sim}-2,000ppm/^{\circ}C$ and stable frequency properties under 100 kHz.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.4
• /
• pp.88-95
• /
• 2015

This paper presents a new analysis of RF negative resistance (RFNR) circuits, known as a negative resistance generator. For accurate equation analysis of RFNR, this study examined the effects of the gate resistance and the source parasitic capacitance of the transistor. In addition, the input admittance of the conventional equation was calculated by looking into the source-terminal of the transistor, whereas that of the proposed equation was calculated by examining the gate-terminal of the transistor. The proposed equation analysis is more accurate than that of the conventional analysis, especially for higher frequency range. This paper verify the accuracy of the proposed analysis at high frequency range using the simulation.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.4
• /
• pp.377-387
• /
• 2021

Fecal contamination levels of discharge water from inland pollution sources were investigated in Iwon-myeon (Taean-gun), South Korea. Gram-negative bacteria were isolated during the investigation and the antimicrobial resistance patterns of the isolates were examined to estimate their impact on the coastal environment. The ranges of total coliform and fecal coliform of 12 samples from four major inland pollution sources were 79-490,000 MPN/100 mL and 2.0-490,000 MPN/100 mL, respectively, with the highest level of fecal contamination at Station No. 3. A total of 137 strains (14 genus) were isolated, of which 86 strains (62.8%) were Enterobacteriaceae. The identified isolates were as follows: Pseudomonas spp. (35 strains), Klebsiella spp. (20 strains), Serratia spp. (20 strains), and Escherichia spp. (19 strains). The isolated Gram-negative bacteria showed the highest antimicrobial resistance to ampicillin (81.8%), followed by amoxicillin/clavulanic acid (64.2%), ceftiofur (61.3%), and cefoxitin (59.1%). Antimicrobials in which less than 10% of isolates showed antimicrobial resistance were ciprofloxacin (3.6%) and gentamicin (2.2%). Resistance to one or more antimicrobials was observed in 121 strains (88.3%) and 84 strains (61.3%) showed a tendency for multiple antimicrobial resistance.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.1
• /
• pp.137-142
• /
• 2015

Trimethoprim-sulfamethoxazole (TMP-SMX) has been used for the treatment of urinary tract infections, but increasing resistance to TMP-SMX has been reported. In this study, we analyzed TMP-SMX resistance genes and their relatedness with integrons and insertion sequence common regions (ISCRs) in uropathogenic gram-negative bacilli. Consecutive nonduplicate TMP-SMX nonsusceptible clinical isolates of E. coli, K. pneumoniae, Acinetobacter spp., and P. aeruginosa were collected from urine. The minimal inhibitory concentration was determined by Etest. TMP-SMX resistance genes (sul and dfr), integrons, and ISCRs were analyzed by PCR and sequencing. A total of 45 E. coli (37.8%), 15 K. pneumoniae (18.5%), 12 Acinetobacter spp. (70.6%), and 9 Pseudomonas aeruginosa (30.0%) isolates were found to be resistant to TMP-SMX. Their MICs were all over 640. In E. coli and K. pneumoniae, sul1 and dfr genes were highly prevalent in relation with integron1. The sul3 gene was detected in E. coli. However, in P. aeruginosa and Acinetobacter spp., only sul1 was prevalent in relation with class 1 integron; however, dfr was not detected and sul2 was less prevalent than in Enterobacteriaceae. ISCR1 and/or ISCR2 were detected in E. coli, K. pneumoniae, and Acinetobacter spp. but the relatedness with TMP-SMX resistance genes was not prominent. ISCR14 was detected in six isolates of E. coli. In conclusion, resistance mechanisms for TMP-SMX were different between Enterobacteriaceae and glucose non-fermenting gram-negative bacilli. Class 1 integron was widely disseminated in uropathogenic gram-negative baciili, so the adoption of prudent use of antimicrobial agents and the establishment of a surveillance system are needed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.6
• /
• pp.590-598
• /
• 2004

An active capacitance circuit which employs series feedback network for the implement of negative resistance and low noise operation is analyzed in depth and its application to low noise active RF BPF's is discussed. Whereas many authors reported a lot of circuits that embody negative resistance circuit most of them have concerns for the equivalent resistance and reactance value at the center frequency. In this case, it could be possible to face a problem that the negative resistance circuit becomes unstable, or have poor flatness in passband because of insufficient forecast for the negative resistance values as the frequency goes higher or lower. In this paper, we extracted the exact equivalent values of this circuit and analyzed the RF characteristics with the varying the values of active devices and feedback circuits and presented the method that the flatness of passband can be improved. We have designed a 4-pole active BPF, which has the bandwidth of 60 ㎒, 0.67 ㏈ insertion loss, 0.3 ㏈ ripple, and noise figure of 3.0 ㏈ at 1.99 ㎓ band.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.41 no.4
• /
• pp.385-391
• /
• 1992

In this paper, the electrical conduction phenomena of oriented polypropylene film were studied. Especially, as for the range of negative characteristics, it is observed that as increasing ambient temperature, the characteristics are shifted gradually towards the low intensity side of applied field with the decreasing width of the range as well as the fact that the current oscillation takes place at the both transition points of the characteristics. Finally, it is also suggestive that the oscillation characteristics observed on the negative resistance range of the biaxially oriented specimen show the possibility to utilize it as active element materials.

• 한국체육학회지인문사회과학편
• /
• v.54 no.2
• /
• pp.253-267
• /
• 2015

This study investigated the effects of perceived organizational justice on innovation resistance among instructors in sport centers and examined the mediating effects of organizational trust on these relationships. Total 274 sport instructors participated in this study. The data were analyzed by structural equation modeling, and the results of this study were as follows: First, distributive justice had a negative effect on psychological resistance, while distributive justice had no significant effect on behavioral resistance. Second, procedural justice had a negative effect on psychological resistance and behavioral resistance. Third, both distributive justice and procedural justice had a positive effect on organizational trust. Fourth, organizational trust had a negative effect on psychological resistance and behavioral resistance. Fifth, organizational trust had a partial mediating effect on the relationship between distributive justice and psychological resistance and a full mediating effect on the relationship between distributive justice and behavioral resistance. Also, organizational trust had a partial mediating effect on the relationship between procedural justice and innovation resistance.

• Journal of Information Technology Applications and Management
• /
• v.16 no.2
• /
• pp.65-77
• /
• 2009

This study explores the major factors that are likely to affect the acceptance and resistance of innovative products and services. The TAM (Technology Acceptance Model) has been widely used for understanding consumer acceptance of new technology. This model displays perceived usefulness and perceived ease of use as antecedents of intention to adopt and use. However, research has reported a variety of preceding variables for technology acceptance. In addition, considering paradoxes of technology, research regarding both acceptance and resistance in an integrated model can explain consumer perception and behavior in detail. The results of this study states that relative benefits, degree of innovation in technology, perceived usefulness and perceived ease of use have had positive influence on the intention to adopt but negative impact on that of resistance. However, alterations of usage and perceived risk positively affects resistance, but also have negative effects on the intention to adopt. Finally, intention to adopt has comparatively greater influence than that of resistance on intention to use. Theoretical and managerial implications of the results are also discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.811-813
• /
• 2003

We investigated the electrical properties of self-assembled (4,4'-Di(ethynylphenyl)-2'-nitro-1-thioacetylbenzene), which has been well known as a conducting molecule having possible application to molecular level negative differential resistance(NDR)[1]. Generally, the phenomenon of NDR can be characterized by the decreasing current with the increasing voltage[2]. To deposit the SAM layer onto gold electrode, we transfer the prefabricated nanopores into a 1mM self-assembly molecules in THF solution. Au(111) substrates were prepared by ion beam sputtering method of gold onto the silicon wafer. As a result, we measured the voltage-current properties and confirmed the negative differential resistance properties of self-assembled organic thin film and measured, using Scanning Tunneling Microscopy(STM).