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>

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.

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.

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.

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.

pH 4.3과 pH 7.0의 과포화용액에서 불소의 농도가 합성 수산화인회석의 결정 성장에 미치는 영향

신현일,박성호,박정원,이찬영 大韓齒科保存學會 2012 Restorative Dentistry & Endodontics Vol.37 No.1

Objectives: Present study was undertaken to investigate the crystal growth onto synthetic hydroxyapatite (HA) seeds in pH 4.3 and pH 7.0 supersaturated solutions with different fluoride concentrations. Materials and Methods: 8 groups of pH 4.3 and 7.0 calcium phosphate supersaturated solutions were prepared with different fluoride concentrations (0, 1, 2 and 4 ppm). Calcium phosphate precipitates yield crystal growth onto the HA seed surface while solutions flow. For evaluation of crystallizing process, the changes of Ca2+, PO43-, F- concentrations of the inlet and outlet solutions were determined. The recovered solid samples were weighed to assess the amount of minerals precipitated, and finally determined their composition to deduce characteristics of crystals. Results: During the seeded crystal growth, there were significantly more consumption of Ca2+, PO43-, F- in pH 4.3 solutions than pH 7.0 (p < 0.05). As fluoride concentration increased in pH 4.3 solution, Ca2+, PO43-, F- consumption in experimental solutions, weight increment of HA seed, and fluoride ratio in crystallized samples were increased. There were significant differences among the groups (p < 0.05). But in pH 7.0 solution, these phenomena were not significant. In pH 7.0 solutions, analyses of crystallized samples showed higher Ca/P ratio in higher fluoride concentration. There were significant differences among the groups (p < 0.05). But in pH 4.3 solution, there were not significant differences in Ca/P ratio. Conclusions: Crystal growth in pH 4.3 solutions was superior to that in pH 7.0 solutions. In pH 4.3 solutions, crystal growth increased with showed in higher fluoride concentration up to 4 ppm.

만성 견비통에 대한 동씨침 치료의 무작위 대조군의 임상 연구

김찬영,권나현,신예지,남동우,김건형,김종인,최도영,이윤호,이재동 WHO COLLABORATING CENTRE FOR TRADITIONAL MEDICINE 2007 東西醫學硏究所 論文集 Vol.2007 No.-

Objectives : To observe the effect of acupuncture treatment in chronic shoulder pain patients. Methods : 36 voluntary patients were randomly assigned to an acupuncture treatment group(E GrouP, n=18) and a control group(C GrouP, n=18). The E Group patients received acupuncture treatment on LI_(15), TE_(14), GB_(21) and Master Dong's acupuncture points, Shin-gwan and Gyun-joong, twice a week for four weeks. The C Group patients received no treatment. All patients in both groups were instructed to practise self exercise in their daily lives. Evaluations were made at baseline and after four weeks of study. The Constant Shoulder Assessment(CSA), Shoulder Pain and Disability Index(SPADI) and the patient's subjective pain was measured by Visual Analogue Scale(VAS). The obtained data was analyzed. Results '. The E Group showed significant(p<0.05) improvement in CSA, SPADI and VAS after four weeks of treatment. The C Group showed significant(p<0.05) improvement in CSA, but the change of SPADI and VAS was insignificant(P>0.05). CSA and SPADI of E Group significantly(p<0.05) improved compared to the C GrouP, but the difference of VAS change in the two groups was insignificant(p>0.05). Conclusions : Four weeks of acupuncture treatment significantly improved CSA, SPADI and VAS. The improvement of CSA and SPADI was significant(p<0.05) compared to untreated patients.

교정용 고무 링의 삽입과 임시 전장관의 수정을 통한 보철 수복 전 인접면 공간 획득: 증례보고

신한얼,노병덕,신유석,이찬영 大韓齒科保存學會 2012 Restorative Dentistry & Endodontics Vol.37 No.2

Proximal caries or coronal defect in posterior teeth may result in the loss of proximal space and drifting of neighboring teeth, which makes restoration difficult. Inability to restore proper contours and to align tooth axis properly are commonly encountered problems when planning tooth restoration. Moreover, tilted teeth aggravate periodontal tissue breakdown, such as pseudo-pocket, and angular osseous defect. The purpose of this case presentation is to describe a simple technique for inducing minor tooth movement with orthodontic separating ring and provisional restoration modification. This method was used to create crown placement space on mesially tilted molar. This method is easy, simple and efficient technique which could be used in interproximal space gaining in selected situation.

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.

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.