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      • KCI등재

        Effect of specific functional groups on oil adhesion from mica substrate: Implications for low salinity effect

        Jiazhong Wu,Fanghui Liu,Hui Yang,Shijing Xu,Quan Xie,Minghui Zhang,TING CHEN,Guangxin Hu,Jinben Wang 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.56 No.-

        Low salinity effect has been in the center of attention as a cost-effective and environmentally friendlytechnique. Wettability alteration of the oil/brine/mica system appears to be the identified mechanism(s)to trigger the low salinity effect. While the effect of water chemistry and minerology on the wettability ofthe system has been extensively investigated, few studies have investigated the effect of specific functiongroups from crude oil on the system wettability, limiting the understanding of how specific functionalgroup contributes to the wettability. We thus experimentally measured the adhesion forces betweenmica surfaces and functional groups (e.g., C6H5–, CH3–, COOH–, and NH2–) in the presence of differentaqueous ionic solutions using chemical force microscopy (CFM). Moreover, to understand thecontribution of the structural force, the traditional Derjaguin–Landau–Verwey–Overbeek (DLVO) theorywas extended (denoted as EDLVO) tofit the force profiles using a Gauss model. Our results showed thatthe adhesion force between mica and functional groups in a decreasing order was –NH2> –COOH> –CH3> –C6H5. We also found that while DLVO forces strongly affected the tip-surface contact due to theinteractions among oil/brine/mica interfaces, the structural forces also played an important role in adistance of 1–20 nm due to the presence of H-bonds between COOH-terminated or NH2-terminated tipand mica surface. We therefore conclude that the structural force largely contributes to the adhesionforce due to the hydrophilicity or polarity of functional groups, and nucleophilic property (such as phenylgroup). Our results suggest that the polarity of the crude oil needs to be considered to screen a candidatereservoir for low salinity waterflooding projects.

      • KCI등재

        Distribution of nitrate and its implication for the contaminant source in groundwater of Huaibei Plain, Anhui Province

        Jiazhong Qian,Lulu Wang,Yong Liu,Boren Wu,Xiaoming Wang 한국지질과학협의회 2015 Geosciences Journal Vol.19 No.3

        High concentration of NO3-N in groundwater can pose risk to human’s health, thus the study of NO3-N contamination in groundwater is a very important issue related to public health. Using a typical agriculture zone, Huaibei plain in Anhui Province of China as a field site, the temporal and spatial variation of groundwater NO3-N concentration was studied using a multivariate statistical factor analysis combined with Kaiser-Meyer- Olkin method based on a hydrogeological investigation from 2005 to 2009 year. The results show: (1) The contaminant in the groundwater of Huaibei Plain in Anhui Province are serious. 10% of the shallow groundwater samples in non-rainy season of 2005 exceeds the recommended value of NO3-N by Chinese drinking water standard (≤20 mg/L), while 17.5% exceeds the recommended value (11.3 mg/L) by EC. (2) About 15% of shallow groundwater in the whole study area was polluted in 2005 with the maximum of 97.67 mg/L; Groundwater NO3-N concentration is higher in non-rainy season than in rainy season. And the NO3-N content in groundwater shows the increasing trend at all three depths sampled from 2005 to 2009 year. (3) Groundwater nitrate pollution mainly derives from anthropogenic activities in Huaibei Plain, Anhui Province. Further quantitative analysis need to be studied in the future.

      • KCI등재

        Synthesis, properties, calculations and applications of small molecular host materials containing oxadiazole units with different nitrogen and oxygen atom orientations for solution-processable blue phosphorescent OLEDs

        Hua Ye,Hongyu Wu,Liangyuan Chen,Songhua Ma,Kaifeng Zhou,Guobing Yan,Jiazhong Shen,Dongcheng Chen,Shi‑Jian Su 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.2

        A series of new small molecules based on symmetric electron-acceptor of 1,3,4-oxadiazole moiety or its asymmetric isomerof 1,2,4-oxadiazole unit were successfully synthesized and applied to solution-processable blue phosphorescent organic lightemittingdiodes for the first time, and their thermal, photophysical, electrochemical properties and density functional theorycalculations were studied thoroughly. Due to the high triplet energy levels (ET, 2.82–2.85 eV), the energy from phosphorescentemitter of iridium(III) bis[(4,6-difluorophenyl)-pyridinate-N,C2′]picolinate (FIrpic) transfer to the host molecules couldbe effectively suppressed and thus assuring the emission of devices was all from FIrpic. In comparison with the para-modeconjugation in substitution of five-membered 1,3,4-oxadiazole in 134OXD, the meta-linkages of 1,2,4-isomer appending withtwo phenyl rings cause the worse conjugation degree and the electron delocalization as well as the lower electron-withdrawingability for the other 1,2,4-oxadiazole-based materials. Noting that the solution-processed device based on 134OXD containing1,3,4-oxadiazole units without extra vacuum thermal-deposited hole/exciton-blocking layer and electron-transportinglayer showed the highest maximum current efficiency (CEmax) of 8.75 cd/A due to the excellent charge transporting ability of134OXD, which far surpassed the similar devices based on other host materials containing 1,2,4-oxadiazole units. Moreover,the device based on 134OXD presented small efficiency roll-off with current efficiency (CE) of 6.26 cd/A at high brightnessup to 100 cd/m2. This work demonstrates different nitrogen and oxygen atom orientations of the oxadiazole-based hostmaterials produce major impact on the optoelectronic characteristics of the solution-processable devices.

      • KCI등재

        An Experimental Study on Seepage within Shale Fractures due to Confining Pressure and Temperature

        Jingping Wang,Haichun Ma,Peichao Feng,Qing Zhang,Jiazhong Qian,Xiaohui Tan,Lei Ma,Daoxiang Wu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.9

        Seepage of groundwater within rock fractures is widespread. The seepage conditions in the fractures can be affected by the stress and temperature conditions. Shale seepage conditions are a complicated coupling of stress and temperature. Experiments were carried out on shale samples containing three types of fractures: a single short fracture (type A), a single long fracture (type B), and symmetrical short fractures (type C). Three temperature conditions were set for type A. The coefficient C, which is defined as the ratio between the seepage pressure and the flow rate, is constant when the temperature effects are slight. Linear correlations between the coefficient C and the temperature were simulated. For type B, four confining pressures were applied using the confining pressure pump. As the confining pressure increases, the seepage pressure increases. The seepage pressure distribution is nonlinear when the flow rate increases to 6 ml/min under a confining pressure of 12 MPa. For type C, three temperature conditions with three confining pressure conditions were analyzed to determine the seepage pressure. The effects of the confining pressure on the seepage pressure are different from those of type B. Nonlinear curves occur under confining pressures of 3 MPa and 6 MPa at 50°C. The seepage pressure values at 70°C are smaller than those at 30°C and 50°C. The coefficient C contour is depicted for the experimental ranges of temperature and confining pressures. The small value region of coefficient C occurs at about 6 MPa and 50°C. The nonlinear increase in the seepage pressure in the fractures occurred when the confining pressure was larger for a single fracture and when the confining pressure was lower for double fractures.

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