Poly(vinyl alcohol) nanocomposites containing reduced graphene oxide coated with tannic acid for humidity sensor

Lim, Min-Young,Shin, Huiseob,Shin, Dong Myung,Lee, Sang-Soo,Lee, Jong-Chan Elsevier 2016 Polymer Vol.84 No.-

<P><B>Abstract</B></P> <P>Poly(vinyl alcohol) (PVA) nanocomposites were prepared by a solution casting method using a reduced graphene oxide coated with tannic acid (rGO-TA) as a filler. The rGO-TA was simply prepared by mixing tannic acid (TA) with graphene oxide (GO). The simple mixing process was found to be effective to reduce GO and to produce covalently-grafted TA layers on the reduced GO. The mechanical properties of PVA were much improved by the addition of rGO-TA because the TA layers increased the compatibility of the reduced GO with PVA matrix. For example, Young's modulus and elongation at break values of PVA were increased by 34.0 and 56.9%, respectively, by adding 1.0 wt% of rGO-TA. In addition, the PVA nanocomposites showed excellent humidity sensing properties over the wide relative humidity range and the long-term stability due to the conductive property of the reduced GO and the enhanced mechanical strength by the effective incorporation of rGO-TA into the PVA matrix.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The rGO-TA was prepared by a facile and green method using a low-cost tannic acid. </LI> <LI> The effect of rGO-TA on the properties of PVA nanocomposites has been studied. </LI> <LI> The rGO-TA improved the important properties for PVA-based humidity sensors. </LI> <LI> The PVA/rGO-TAs are promising materials for high-performance humidity sensors. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

장력구동방식의 역감제시 시스템

신석두,강원찬,오금곤,김영동 조선대학교 에너지.자원신기술연구소 2000 에너지·자원신기술연구소 논문지 Vol.22 No.2

In this paper, we have developed a new Force-Display system using tendon-driven method. The proposed system is based on the HIR Lab Haptic library, which calculates the real position and renders the reflecting force data to device rapidly. The system is composed of device based tendon-driving method, high-speed controller and Haptic rendering library. The developed system will be used on constructing the dynamical virtual environment. To show the efficiency of our system, we designed simulation program which can display the moving force (attaching, grabbing, rotating) on two virtual point. As the result of the experiment, our proposed system shows much higher resolution than any others.

동하중 측정 신호처리의 개발에 관한 연구

신영균,이영준,박찬원,신형재,안광희 江原大學校 産業技術硏究所 1998 産業技術硏究 Vol.18 No.-

A high speed and stable A/D conversion data process is required to weigh a mass on moving conveyer weighing platter. The paper presents a new method to obtain stable and fast automatic weighing A/D conversion data process. Dynamic weighting system which is constructed with dual load cell is realized by the stable A/D conversion data preocess algorithm using DSP. The proposed memthod is applied to the real design, and that experimental results showed good performances of the weighing stability.

苛性소다 處理에 依한 밀짚의 飼料價値 增進 硏究

辛炯泰,金贊昊,金鍾奭,宋永祿,林泰鎭 成均館大學校 1982 論文集 Vol.32 No.-

Nylon bag dry matter digestibility (NBDMD, %), nylon bag organic matter digestibility (NBOMD, %) and chemical compositions were analysed to evaluate the nutritive values of 5 varieties of NaOH-treated wheat straws (Jangkwang, Wonkwang, Suwon 210, Suwon 211, Naemil) by using Korean native male goats. Three grams of dried samples by grinding with 2.45㎜ Wiley mill screen were put into a bag 9×14㎠ made of 100 mesh nylon. These bags were put into the ventral sac of the rumen and taken out at the end of 72 hours. They were washed, dried in an oven at 105℃ for 24 hours and weighed “NBDMD” (%) and ashed in an muffle furnace at 600℃ or 24 hours and weighed “NBOMD”(%). The results which were obtained with this experiment were as follows: 1. Nylon bag dry matter digestibility (NBDMD, %) and nylon bag organic matter digestibility (NBOMD, %) of NaOH-treated wheat straws were highly significant different (p<0.01) in different levels of NaOH treatment and of different varieties of wheat straws. 2. The relationship between total mean NBDMD (%, Y_1) of 5 varieties of wheat straws and NaOH concentration (%, X) at 72 hours rumen incubation was: Y_1=34.57+3.56X(r=0.92^**) 3. The relationship between total mean MBOMD (%, Y_2) of 5 varieties of wheat straws and NaOH concentration (%, X) at 72 hours rumen incubation was: Y_2=32.02+2.46X(r=0.92^**) 4. The orders of NBDMD(%) and NBOMD(%) for 5 varieties of wheat straws were Suwon 210, Suwon 211, Naemil, Jangkwang, Wonkwang and Suwon 211, Suwon 210, Naemil, Jangkwang, Wonkwang, respectively. 5. The optimum level of NaOH for improving NBDMD(%) from 5 varieties of wheat straws, on the basis of Blaxter et al. (1961), was 6% NaOH.

폐분체 도료의 재활용 방안에 관한 연구

신동철,김영훈,이순기,김경원,신선명,강헌찬 동아대학교 환경문제연구소 1999 硏究報告 Vol.22 No.1

With the progress of industry, the much more demand of paint around us grows rapidly. However, the whole quantity of raw materials used to make powder coatings is presently imported to fill the domestic needs. Moreover, it is well known that the waste powder coatings from the domestic industries are mostly incinerated. The method of destructing the waste powder coatings by fire causes VOC to be generated, and this results in some serious environmental problems such as air pollution and so on. Therefore, the effective and proper measure must be devised to reuse the waste powder coatings for the purpose of eliminating waste of resources and avoiding the outflow of foreign currency. This study aims to make the plan to recycle the waste powder coatings, and its conclusion is drawn as follows: First, it can be seen that the waste powder coatings with a weak electrostatic power restore gradually to the original state of electrostatic power through the process of fusion and retreatment. Second, it can be estimated that those coatings, with the use of the cyclon, can be removed by dividing a powder of particles less than 10㎛. Third, it can be ascertained that the possibility of reusing the waste powder coatings is proved when it is divided into particles by cyclon and a revolving screen after the process of fusion, rolling, crushing and pulverization.

쇄골 간부 골절 불유합의 수술적 치료 : 재건 금속판 고정 및 골 이식술 Reconstruction Plate Fixation and Bone Grafting

변영수,유찬훈,안혁수,문성건,신동주,박준우 대한골절학회 2003 대한골절학회지 Vol.16 No.2

목 적: 쇄골 간부 골절 불유합에 대하여 관혈적 정복, 재건 금속판 고정 및 골 이식을 시행하고 술후 조기 관절 운동을 허용한 저자들의 경험을 보고하는 것이다. 대상 및 방법: 1997년 1월부터 2001년 12월까지 수술적 치료를 시행한 쇄골 간부 골절 불유합 16예를 대상으로 하였다. 위축성 불유합이 10예, 비후성 불유합이 6예였으며, 수상 후 불유합에 대한 수술까지의 기간은 평균 6.5개월이었다. 수술적 치료로 불유합 부위를 노출시켜 섬유조직을 제거하고 골수강을 천공하였으며, 골편을 정복하고 재건 금속판으로 고정하였으며, 자가 골 이식을 하였다. 수술 후 관절 운동은 1주일 이내에 시작하였다. 결 과: 평균 추시 기간은 22.0개월이었으며, 전 예에서 평균 10.0주에 골유합을 얻었다. 최종 추시 시의 견관절 운동범위는 전 예에서 정상으로 회복되었으며, 나이가 50게 이상인 6예 중 3예에서 동측 견관절에 간헐적인 동통을 호소하였다. 술후 감염, 재검 금속판의 파손, 고정상실, 불유합, 재골절 등의 합병증은 발생치 않았다. 결 론: 쇄골 간부 골절 불유합에 대한 관혈적 정복, 재건 금속판 고정 및 골 이식은 안정성 고정으로 조기 재활이 가능하고 견고한 골유합을 얻을 수 있어 안전하고 확실한 치료방법으로 사료된다. Purpose: The purpose of this study is to present out experience with open reduction, 3.5-㎜ reconstruction plate fixation, bone-grafting, and postoperative early mobilization for nonunions of midshaft clavicular fratures. Materials and Methods: Sixteen patients were treated operatively for nonunions of the midshaft of the clavicle from 1997 to 2001. Ten nonunions were atrophic and six were hypertrophic. Nonunion had been present for an average of 6.5 months. The operative technique included removing the fibrous tissue from the nonunion site and opening the medullary canal, reduction of the fracture and fixation with a 3.5-㎜ reconstruction plate, and bone-grafting. Postoperative mobilization started within one week. Results: The average duration of follow-up was 22.0 months. All fracture were united in an average of 10.0 weeks. All patients had full range of motion of the ipsilateral shoulder, but 3 our of 6 patients who were more than 50 years old complained occasional pain in the ipsilateral shoulder at the final follow-up examination. There were no major complications of postoperative infection, metal failure of the plate, loss of fixation, nonunion, and refracture after removal of the implant. Conclusion: The technique of open reduction, reconstruction plate fixation, and bone-grafting is a safe and reliable method to allow early rehabilitation by stable fixation and to predict a high rate of union for nonunions of midshaft clavicular fractures.

고무질 보강 식품포장용 LDPE필름의 기계적 강도와 기체투과 선택성

한신,강용구,박찬영 전남대학교 촉매연구소 2000 觸媒硏究 論文集 Vol.21 No.-

To improve the mechanical strength of the functional LDPE packaging film that has deficiency in the strength, though the film is active in vitality and has selective permeability for specific gases such as ethylene and carbon dioxide, this work blends a rubbery polymer, ethylene propylene monomeric rubber(EPM), in the LDPE film, and examines the mechanical strength and the permeability to assess preserving the functionality of freshness keeping of product. Overcoming the defect of incomplete coupling of the ceramic powder to the LDPE film is to use a coupling agent KBM-503( γ -methacryloxy propyl trimethoxy silane) of Shinetsu company in Japan. The optimum blending ratio of the EPM was about 5 percent in weight. The blended film reserves the selective gas permeability in relatively equivalent capacity of the non-rubbery film. The 5 percent EPM blended film has stronger mechanical strength than that made without the EPM, The strength approaches to the pure LDPE film. In conclusion, this work presents the method of improving mechanical strength without any depression in its freshness keeping functionality of the conventional packaging film.

프로그래머 生産性 向上을 위한 實證的 硏究

이병찬,권영직,신호균 대구대학교 산업기술연구소 1989 産業技術硏究 Vol.8 No.-

This study first searched the theoretical background of programmar productivity related with white coller productivity and carried an empirical study for improving the productivity. In experimental study, productivity was not measured by programming cost but by central processing unit time(qualitative aspects), and it was analyzed by COBOL language and 16 bit personal computer. Also, three file organization method and three access method were selected with this experiment. The experiment was conducted with test data for a programs by individual programming. The result was that relative file is more efficient regardless of updated ratio in file organization and dynamic method of random method is more efficient in file access method in case of 500 updated data, random access method in more efficient in the other cases. Also sequential was more efficient in input in case of 500 updated data, and relative file was efficient in output.

충청도 지역 일대 저품위 질석의 팽창 특성에 관해서

강헌찬,김영훈,김광수,신선명 동아대학교 건설기술연구소 1996 硏究報告 Vol.20 No.1

The propose of this thesis was to study the usage of the low-grade Vermiculite from the Chung Chong province and also to increase its Value-added. A series of experiments have been done for separation as well as heat-expansion characteristics of the Chung Chong Vermiculite some conclusions can be drawn as follows; 1. Vermiculite from Chung-Yang and Hong-Shung areas wear better than that from Palabora's mine in South Africa in terms of the usefulness for an organic fertilizer. 2. The ratio of the volume expansion of Vermiculite increased along with the temperature. 3. In general, the ratio of volume expansion of the vermiculite from Chung-Yang, Hong-Shung and Palabora's mine in South Africa increased with temperature. But it decreased temporarily in the vicinity of 850℃. The result seems to be due to temporary decrease in the latent heat as the crystal water in the crystals such as Ca_(10)(Mg,Fe)₂A1₄Si_(9)O₃₄(OH)₄, K(Fe,Mg)₃AlSi₃O_(10)(OH)₂and K (Fe,Mg)₃AlSi₃O_(10)(OH)₂evaporated. 4. Above 1050℃, the crystal structure began to change and resulted in partial destruction to produce some dusts. Finally sintering occurred.

有機農業의 實態와 發展에 관한 事例 硏究 : 忠南 洪城郡 洪東面 有機農家를 中心으로

尹英相,洪性贊,金成敏,具漢謨,申東一,金昌護,姜熙慶 公州大學校 資源科學硏究所 1997 資源科學硏究論文集 Vol.5 No.-

This study was carried out to improve the organic farming system about crop cultivation, compost production and application, plant diseases & pest control, weed control and marketing system of organic farming products to the case study in Chungnam Hongdong area. Agricultural technologies concerning pest & diseases control, weed control and compost production are not established due to lacks of systemized researches by the agricultural scientist, and agricultural machines profitable to this works had not developed yet. In cropping system, reasonable crop rotation had not conducted. The related cultivation of vegetables on the same ground for a long time cause a various plant disease easily. So crop rotation is a reasonable method about soil nutrient utility and soil disease control. It is a good method that introduce the barley and wheat in this field crop system. Those crop have a long root, so can use the other nutrient against the vegetable. In organic farming products, the safety and quality of products by the National Agricultural Products Inspection Center had not inspected except rice, lettus and apple. Inspection is needed for the development of organic farming and mutual confidence between producer and consumer, because the mutual confidence is a major thing to sustain the organic farming. In products marketing, it is more need for the information of organic farming products. Nowaday most products are marketed in Seoul region, but it is not a good method. To search the consumer in near region is a good method for decrease the cost of conveyance and maintain the quality of products. The varieties of distribution structure of organic farming products are required. The products are sold to department store in large city and the prices are about 30% higher than normal products. But when those are supplied in near region, the prices of those are similar to normal products. Direct transactions in near regions is a good method for decrease the cost of conveyance and strength the mutual confidence between producer and consumer.