What Affects Chinese Residents’ Perceptions of Climate Change?

The theme of global sustainable development has changed from environmental management to climate governance, and relevant policies on climate governance urgently need to be implemented by the public. The public understanding of climate change has become the prerequisite and basis for implementing various climate change policies. In order to explore the affected factors of climate change perception among Chinese residents, this study was conducted across 31 provinces and regions of China through field household surveys and interviews. Combined with the residents&rsquo; perception of climate change with the possible affected factors, the related factors affecting Chinese residents&rsquo; perception of climate change were explored. The results show that the perceptive level of climate change of Chinese residents is related to the education level and the household size of residents. Improving public awareness of climate change risk in the context of climate change through multiple channels will also help to improve residents&rsquo; awareness of climate change. On the premise of improving the level of national education, improving education on climate change in school education and raising awareness of climate change risk among dependents will help to improve the level of Chinese residents&rsquo; awareness of climate change, which could be instrumental in promoting public participation in climate change mitigation an dadaptation actions</p

Isotope Effect on the Thermal Conductivity of Graphene

The thermal conductivity (TC) of isolated graphene with different concentrations of isotopes (C13) is studied with equilibrium molecular dynamics method at 300K. In the limit of pure C12 or C13 graphene, TC of graphene in zigzag and armchair directions are ~630 W/mK and ~1000W/mK, respectively. We find that the TC of graphene can be maximally reduced by ~80%, in both armchair and zigzag directions, when a random distribution of C12 and C13 is assumed at different doping concentrations. Therefore, our simulation results suggest an effective way to tune the TC of graphene without changing its atomic and electronic structure, thus yielding a promising application for nanoelectronics and thermoelectricity of graphene based nano-device.Comment: 8 pages, 4 figures, to be published in Journal of Nanomaterial

Reparameterization of the REBO-CHO potential for graphene oxide molecular dynamics simulations

The reactive empirical bond order (REBO) potential developed by Brenner et al. [Phys. Rev. B 42, 9458 (1990); J. Phys. Condens. Matter 14, 783 (2002)] for molecular dynamics (MD) simulations of hydrocarbons, and recently extended to include interactions with oxygen atoms by Ni et al. [J. Phys. Condens. Matter 16, 7261 (2004)], is modified for graphene-oxide (GO). Based on density-functional-theory (DFT) calculations, we optimized the REBO-CHO potential (in which CHO denotes carbon, hydrogen, and oxygen) to improve its ability to calculate the binding energy of an oxygen atom to graphene and the equilibrium C-O bond distances. In this work, the approach toward the optimization is based on modifying the bond order term. The modified REBO-CHO potential is applied to investigate the properties of some GO samples.close111

Thermal Properties of Isotopically Engineered Graphene

In addition to its exotic electronic properties graphene exhibits unusually high intrinsic thermal conductivity. The physics of phonons - the main heat carriers in graphene - was shown to be substantially different in two-dimensional (2D) crystals, such as graphene, than in three-dimensional (3D) graphite. Here, we report our experimental study of the isotope effects on the thermal properties of graphene. Isotopically modified graphene containing various percentages of 13C were synthesized by chemical vapor deposition (CVD). The regions of different isotopic composition were parts of the same graphene sheet to ensure uniformity in material parameters. The thermal conductivity, K, of isotopically pure 12C (0.01% 13C) graphene determined by the optothermal Raman technique, was higher than 4000 W/mK at the measured temperature Tm~320 K, and more than a factor of two higher than the value of K in a graphene sheets composed of a 50%-50% mixture of 12C and 13C. The experimental data agree well with our molecular dynamics (MD) simulations, corrected for the long-wavelength phonon contributions via the Klemens model. The experimental results are expected to stimulate further studies aimed at better understanding of thermal phenomena in 2D crystals.Comment: 14 pages, 3 figure

Formation energy of graphene oxide structures: a molecular dynamics study on distortion and thermal effects

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOAb initio predictions for the stability of different graphene oxide (GO) structures have been shown to conflict with experimental observations. While ab initio studies predict that the most stable GOs are fully oxygen-covered (either with epoxide or hydroxyl), stable asproduced GOs are partially oxygen-covered and predominantly epoxide-covered structures. Although this discrepancy is being examined in terms of calculations of free energies of GOs and large diffusion energy-barriers for oxygen groups on graphene, there is still a lack of understanding on the energetic properties of GOs using classical molecular dynamics, which is able to investigate their structural distortion. Here, using the reactive empirical bond order (REBO) molecular dynamics potential, we compute the free energy and binding energy of GOs at different oxygen concentrations and epoxide to hydroxyl ratios, as well as the distortion energies of graphene lattice. Although epoxide causes more distortion on the carbon hexagonal planar structure, it provides more stability to the GO structure. The difference between free energy and binding energy of GOs is shown to be independent of oxygen coverage. These results allow gaining more insight on the issue of GO stability and show that REBO can capture most of experimental properties of GOs.Ab initio predictions for the stability of different graphene oxide (GO) structures have been shown to conflict with experimental observations. While ab initio studies predict that the most stable GOs are fully oxygen-covered (either with epoxide or hydroxyl), stable asproduced GOs are partially oxygen-covered and predominantly epoxide-covered structures. Although this discrepancy is being examined in terms of calculations of free energies of GOs and large diffusion energy-barriers for oxygen groups on graphene, there is still a lack of understanding on the energetic properties of GOs using classical molecular dynamics, which is able to investigate their structural distortion. Here, using the reactive empirical bond order (REBO) molecular dynamics potential, we compute the free energy and binding energy of GOs at different oxygen concentrations and epoxide to hydroxyl ratios, as well as the distortion energies of graphene lattice. Although epoxide causes more distortion on the carbon hexagonal planar structure, it provides more stability to the GO structure. The difference between free energy and binding energy of GOs is shown to be independent of oxygen coverage. These results allow gaining more insight on the issue of GO stability and show that REBO can capture most of experimental properties of GOs.84365374CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOSem informação2012/10106-8Wu, X., Sprinkle, M., Li, X., Ming, F., Berger, C., De Heer, W.A., Epitaxial-graphene/graphene-oxide junction: An essential step towards epitaxial graphene electronics (2008) Phys Rev Lett, 101, p. 026801. , http://dx.doi.org/10.1103/PhysRevLett.101.026801Mattson, E.C., Pu, H., Cui, S., Schofield, M.A., Rhim, S., Lu, G., Evidence of nanocrystalline semiconducting graphene monoxide during thermal reduction of graphene oxide in vacuum (2011) ACS Nano, 5 (12), pp. 9710-9717. , http://dx.doi.org/10.1021/nn203160nJung, I., Dikin, D.A., Piner, R.D., Ruoff, R.S., Tunable electrical conductivity of individual graphene oxide sheets reduced at ''low'' temperatures (2008) Nano Lett, 8 (12), pp. 4283-4287. , http://dx.doi.org/10.1021/nl8019938Yan, J.-A., Xian, L., Chou, M.Y., Structural and electronic properties of oxidized graphene (2009) Phys Rev Lett, 103, p. 086802. , http://dx.doi.org/10.1103/PhysRevLett.103.086802Balog, R., Jørgensen, B., Nilsson, L., Andersen, M., Rienks, E., Bianchi, M., Bandgap opening in graphene induced by patterned hydrogen adsorption (2010) Nat Mater, 9, pp. 315-319. , http://dx.doi.org/10.1038/NMAT2710Schniepp, H.C., Li, J.-L., McAllister, M.J., Sai, H., Herrera-Alonso, M., Adamson, D.H., Functionalized single graphene sheets derived from splitting graphite oxide (2006) J Phys Chem B, 110 (17), pp. 8535-8539. , http://dx.doi.org/10.1021/jp060936fPark, S., Ruoff, R.S., Chemical methods for the production of graphenes (2009) Nat Nanotechnol, 4, pp. 217-224. , http://dx.doi.org/10.1038/nnano.2009.58Gao, W., Alemany, L.B., Ci, L., Ajayan, P.M., New insights into the structure and reduction of graphite oxide (2009) Nat Chem, 1, pp. 403-408. , http://dx.doi.org/10.1038/NCHEM.281Mathkar, A., Tozier, D., Cox, P., Ong, P., Galande, C., Balakrishnan, K., Controlled, stepwise reduction and band gap manipulation of graphene oxide (2012) J Phys Chem Lett, 3 (8), pp. 986-991. , http://dx.doi.org/10.1021/jz300096tMarcano, D.C., Kosynkin, D.V., Berlin, J.M., Sinitskii, A., Sun, Z., Slesarev, A., Improved synthesis of graphene oxide (2010) ACS Nano, 4 (8), pp. 4806-4814. , http://dx.doi.org/10.1021/nn1006368Fan, Z.-J., Kai, W., Yan, J., Wei, T., Zhi, L.-J., Feng, J., Facile synthesis of graphene nanosheets via Fe reduction of exfoliated graphite oxide (2011) ACS Nano, 5 (1), pp. 191-198. , http://dx.doi.org/10.1021/nn102339tAcik, M., Lee, G., Mattevi, C., Chhowalla, M., Cho, K., Chabal, Y.J., Unusual infrared-absorption mechanism in thermally reduced graphene oxide (2010) Nat Mater, 9, pp. 840-845. , http://dx.doi.org/10.1038/nmat2858Tian, H., Xie, D., Yang, Y., Ren, T.L., Zhang, G., Wang, Y.F., A novel solid-state thermal rectifier based on reduced graphene oxide (2012) Sci Rep, 2, p. 523. , http://dx.doi.org/10.1038/srep00523Xiao, N., Dong, X., Song, L., Liu, D., Tay, Y., Wu, S., Enhanced thermopower of graphene films with oxygen plasma treatment (2011) ACS Nano, 5 (4), pp. 2749-2755. , http://dx.doi.org/10.1021/nn2001849Eda, G., Lin, Y.Y., Miller, S., Chen, C.W., Su, W.F., Chhowalla, M., Transparent and conducting electrodes for organic electronics from reduced graphene oxide (2008) Appl Phys Lett, 92, p. 233305. , http://dx.doi.org/10.1063/1.2937846Eda, G., Fanchini, G., Chhowalla, M., Large-area ultrathin films of reduced graphene oxide as a transparent and flexible electronic material (2008) Nat Nanotechnol, 3, pp. 270-274. , http://dx.doi.org/10.1038/nnano.2008.83Wang, L., Lee, K., Sun, Y.-Y., Lucking, M., Chen, Z., Zhao, J.J., Graphene oxide as an ideal substrate for hydrogen storage (2009) ACS Nano, 3 (10), pp. 2995-3000. , http://dx.doi.org/10.1021/nn900667sDikin, D.A., Stankovich, S., Zimney, E.J., Piner, R.D., Dommett, G.H.B., Evmenenko, G., Preparation and characterization of graphene oxide paper (2007) Nat (London), 448, pp. 457-460. , http://dx.doi.org/10.1038/nature06016Ramanathan, T., Abdala, A.A., Stankovich, S., Dikin, D.A., Herrera-Alonso, M., Piner, R.D., Functionalized graphene sheets for polymer nanocomposites (2008) Nat Nanotechnol, 3, pp. 327-331. , http://dx.doi.org/10.1038/nnano.2008.96Vinod, S., Tiwary, C.S., Autreto, P.A.S., Taha-Tijerina, J., Ozden, S., Chipara, A.C., Low-density three-dimensional foam using self-reinforced hybrid two-dimensional atomic layers (2014) Nat Commun, 5, p. 4541. , http://dx.doi.org/10.1038/ncomms5541Boukhvalov, D.W., Katsnelson, M.I., Modeling of graphite oxide (2008) J Am Chem Soc, 130 (32), pp. 10697-10701. , http://dx.doi.org/10.1021/ja8021686Lahaye, R.J.W.E., Jeong, H.K., Park, C.Y., Lee, Y.H., Density functional theory study of graphite oxide for different oxidation levels (2009) Phys Rev B, 79, p. 125435. , http://dx.doi.org/10.1103/PhysRevB.79.125435Wang, L., Sun, Y.Y., Lee, K., West, D., Chen, Z.F., Zhao, J.J., Stability of graphene oxide phases from first-principles calculations (2010) Phys Rev B, 82, p. 161406R. , http://dx.doi.org/10.1103/PhysRevB.82.161406Lu, N., Yin, D., Li, Z., Yang, J., Structure of graphene oxide: Thermodynamics versus kinetics (2011) J Phys Chem C, 115 (24), pp. 11991-11995. , http://dx.doi.org/10.1021/jp204476qLiu, L., Wang, L., Gao, J., Zhao, J., Gao, X., Chen, Z., Amorphous structural models for graphene oxides (2012) Carbon, 50, pp. 1690-1698. , http://dx.doi.org/10.1016/j.carbon.2011.12.014Kim, S., Zhou, S., Hu, Y., Acik, M., Chabal, Y.J., Berger, C., Roomtemperature metastability of multilayer graphene oxide films (2012) Nat Mater, 11, pp. 544-549. , http://dx.doi.org/10.1038/nmat3316Huang, B., Xiang, H., Xu, Q., Wei, S.-H., Overcoming the phase inhomogeneity in chemically functionalized graphene: The case of graphene oxides (2013) Phys Rev Lett, 110, p. 085501. , http://dx.doi.org/10.1103/PhysRevLett.110.085501Zhou, S., Bongiorno, A., Origin of the chemical and kinetic stability of graphene oxide (2013) Sci Rep, 3, p. 2484. , http://dx.doi.org/10.1038/srep02484Andremkhoyan, K., Contryman, A.W., Silcox, J., Stewart, D.A., Eda, G., Mattevi, C., Atomic and electronic structure of graphene-oxide (2009) Nano Lett, 9 (3), pp. 1058-1063. , http://dx.doi.org/10.1021/nl8034256Saxena, S., Tyson, T.A., Shukla, S., Negusse, E., Chen, H., Bai, J., Investigation of structural and electronic properties of graphene oxide (2011) Appl Phys Lett, 99, p. 013104. , http://dx.doi.org/10.1063/1.3607305Lee, G., Lee, B., Kim, J., Cho, K., Ozone adsorption on graphene: Ab initio study and experimental validation (2009) J Phys Chem C, 113 (32), pp. 14225-14229. , http://dx.doi.org/10.1021/jp904321nYamaguchi, H., Murakami, K., Eda, G., Fujita, T., Guan, P., Wang, W., Field emission from atomically thin edges of reduced graphene oxide (2011) ACS Nano, 5 (6), pp. 4945-4952. , http://dx.doi.org/10.1021/nn201043aXu, Z., Xue, K., Engineering graphene by oxidation: A firstprinciples study (2010) Nanotechnology, 21, p. 045704. , http://dx.doi.org/10.1088/0957-4484/21/4/045704Lee, G., Cho, K., Electronic structures of zigzag graphene nanoribbons with edge hydrogenation and oxidation (2009) Phys Rev B, 79, p. 165440. , http://dx.doi.org/10.1103/PhysRevB.79.165440Lee, G., Kim, K.S., Cho, K., Theoretical study of the electron transport in graphene with vacancy and residual oxygen defects after high-temperature reduction (2011) J Phys Chem C, 115 (19), pp. 9719-9725. , http://dx.doi.org/10.1021/jp111841wAcik, M., Lee, G., Mattevi, C., Pirkle, A., Wallace, R.M., Chhowalla, M., The role of oxygen during thermal reduction of graphene oxide studied by infrared absorption spectroscopy (2011) J Phys Chem C, 115 (40), pp. 19761-19781. , http://dx.doi.org/10.1021/jp2052618Gong, C., Acik, M., Abolfath, R.M., Chabal, Y., Cho, K., Graphitization of graphene oxide with ethanol during thermal reduction (2012) J Phys Chem C, 116 (18), pp. 9969-9979. , http://dx.doi.org/10.1021/jp212584tAbolfath, R., Cho, K., Computational studies for reduced graphene oxide in hydrogen-rich environment (2012) J Phys Chem A, 116 (7), pp. 1820-1827. , http://dx.doi.org/10.1021/jp2107439Srinivasan, S.G., Van Duin, A.C.T., Molecular-dynamics-based study of the collisions of hyperthermal atomic oxygen with graphene using the ReaxFF reactive force field (2011) J Phys Chem A, 115 (46), pp. 13269-13280. , http://dx.doi.org/10.1021/jp207179xBagri, A., Mattevi, C., Acik, M., Chabal, Y.J., Chhowalla, M., Shenoy, V.B., Structural evolution during the reduction of chemically derived graphene oxide (2010) Nat Chem, 2, pp. 581-587. , http://dx.doi.org/10.1038/nchem.686Suk, J.W., Piner, R.D., An, J., Ruoff, R.S., Mechanical properties of monolayer graphene oxide (2010) ACS Nano, 4 (11), pp. 6557-6564. , http://dx.doi.org/10.1021/nn101781vMedhekar, N.V., Ramasubramaniam, A., Ruoff, R.S., Shenoy, V.B., Hydrogen bond networks in graphene oxide composite paper: Structure and mechanical properties (2010) ACS Nano, 4 (4), pp. 2300-2306. , http://dx.doi.org/10.1021/nn901934uFonseca, A.F., Lee, G., Borders, T.L., Zhang, H., Kemper, T.W., Shan, T.R., Reparameterization of the REBO-CHO potential for graphene oxide molecular dynamics simulation (2011) Phys Rev B, 84, p. 075460. , http://dx.doi.org/10.1103/PhysRevB.84.075460Zhang, H., Fonseca, A.F., Cho, K., Tailoring thermal transport property of graphene through oxygen functionalization (2014) J Phys Chem C, 118 (3), pp. 1436-1442. , http://dx.doi.org/10.1021/jp4096369Mu, X., Wu, X., Zhang, T., Go, D.B., Luo, T., Thermal transport in graphene oxide-From ballistic extreme to amorphous limit (2014) Sci Rep, 4, p. 3909. , http://dx.doi.org/10.1038/srep03909Lin, S., Buehler, M.J., Thermal transport in monolayer graphene oxide: Atomistic insights into phonon engineering through surface chemistry (2014) Carbon, 77, pp. 351-359. , http://dx.doi.org/10.1016/j.carbon.2014.05.038Ni, B., Lee, K.-H., Sinnott, S.B., A reactive empirical bond order (REBO) potential for hydrocarbon-oxygen interactions (2004) J Phys: Condens Matter, 16, pp. 7261-7275. , http://dx.doi.org/10.1088/0953-8984/16/41/008Chenoweth, K., Van Duin, A.C.T., Goddard, W.A., III, ReaxFF reactive force field for molecular dynamics simulations of hydrocarbon oxidation (2008) J Phys Chem A, 112 (5), pp. 1040-1053. , http://dx.doi.org/10.1021/jp709896wHummers, W.S., Offeman, R.E., Preparation of graphitic oxide (1958) J Am Chem Soc, 80 (6). , http://dx.doi.org/10.1021/ja01539a017.1339-1339Dreyer, D.R., Park, S., Bielawski, C.W., Ruoff, R.S., The chemistry of graphene oxide (2010) Chem Soc Rev, 39, pp. 228-240. , http://dx.doi.org/10.1039/B917103GSzabó, T., Berkesi, O., Forgó, P., Josepovits, K., Sanakis, Y., Petridis, D., Evolution of surface functional groups in a series of progressively oxidized graphite oxides (2006) Chem Mater, 18 (11), pp. 2740-2749. , http://dx.doi.org/10.1021/cm060258+Lerf, A., He, H., Riedl, T., Forster, M., Klinowski, J., 13C and 1H MAS NMR studies of graphite oxide and its chemically modified derivatives (1997) Solid State Ionics, 101-103, pp. 857-862. , http://dx.doi.org/10.1016/S0167-2738(97)00319-6He, H., Klinowski, J., Forster, M., Lerf, A., A new structural model for graphite oxide (1998) Chem Phys Lett, 287 (1-2), pp. 53-56. , http://dx.doi.org/10.1016/S0009-2614(98)00144-4Lerf, A., He, H., Forster, M., Klinowski, J., Structure of graphite oxide revisited (1998) J Phys Chem B, 102 (23), pp. 4477-4482. , http://dx.doi.org/10.1021/jp9731821Cassagneau, T., Guerin, F., Fendler, J.H., Preparation and characterization of ultrathin films layer-by-layer selfassembled from graphite oxide nanoplatelets and polymers (2000) Langmuir, 16 (18), pp. 7318-7324. , http://dx.doi.org/10.1021/la000442oHontoria-Lucas, C., López-Peinado, A.J., De López-González, J.D., Rojas-Cervantes, M.L., Martín-Aranda, R.M., Study of oxygencontaining groups in a series of graphite oxides: Physical and chemical characterization (1995) Carbon, 33 (11), pp. 1585-1592. , http://dx.doi.org/10.1016/0008-6223(95)00120-3Szabó, T., Tombácz, E., Illés, E., Dékány, I., Enhanced acidity and pH-dependent surface charge characterization of successively oxidized graphite oxides (2006) Carbon, 44 (3), pp. 537-545. , http://dx.doi.org/10.1016/j.carbon.2005.08.005Shin, H.-J., Kim, K.K., Benayad, A., Yoon, S.-M., Park, H.K., Jung, I.-S., Efficient reduction of graphite oxide by sodium borohydride and its effect on electrical conductance (2009) Adv Funct Mater, 19 (12), pp. 1987-1992Zhu, J., Andres, C.M., Xu, J., Ramamoorthy, A., Tsotsis, T., Kotov, N.A., Pseudonegative thermal expansion and the state of water in graphene oxide layered assemblies (2012) ACS Nano, 6 (9), pp. 8357-8365. , http://dx.doi.org/10.1021/nn3031244Reuter, K., Scheffler, M., Composition, structure, and stability of RuO2(110) as a function of oxygen pressure (2002) Phys Rev B, 65, p. 035406. , http://dx.doi.org/10.1103/PhysRevB.65.035406CODATA recommended key values for thermodynamics, 1977. Report of the CODATA Task Group on key values of thermodynamics, 1977 (1978) J Chem Thermodyn, 10 (10), pp. 903-906. , http://dx.doi.org/10.1016/0021-9614(78)90050-2Yan, J.-A., Chou, M.Y., Oxidation functional groups on graphene: Structural and electronic properties (2010) Phys Rev B, 82 (12), p. 125403. , http://dx.doi.org/10.1103/PhysRevB.82.125403Jung, I., Field, D.A., Clark, N.J., Zhu, Y., Yang, D., Piner, R.D., Reduction kinetics of graphene oxide determined by electrical transport measurements and temperature programmed desorption (2009) J Phys Chem C, 113 (43), pp. 18480-18486. , http://dx.doi.org/10.1021/jp904396jLu, N., Huang, Y., Li, H., Li, Z., Yang, J., First principles nuclear magnetic resonance signatures of graphene oxide (2010) J Chem Phys, 133, p. 034502. , http://dx.doi.org/10.1063/1.3455715This work is supported by Nano Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2012M3A7B4049888). A.F. Fonseca is a research fellow of the Brazilian agency CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) and acknowledges financial support from FAEPEX/UNICAMP and Grant #2012/10106-8 from São Paulo Research Foundation (FAPESP)

Thermal transport in graphene and effects of vacancy defects

We have performed molecular dynamics simulations to investigate phonon transport in graphene at 300 K with the Green-Kubo method. We show that the thermal conductivity (TC) of pristine graphene is 2903 +/- 93 W/mK, and the out-of-plane phonon mode contribution is 1202 +/- 32 W/mK. We further investigate thermal transport in graphene with different vacancy defect concentrations, and the TC shows that it is possible to achieve a maximum of a thousandfold reduction with a high defect density.open654

Tailoring Thermal Transport Property of Graphene through Oxygen Functionalization

We compute thermal conductivity of graphene oxide at room temperature with molecular dynamics simulation. To validate our simulation model, we have investigated phonon scattering in graphene due to crystal boundary length and isotope defect, both of which are able to diagnose the behavior of long wavelength and short wavelength phonon scattering. Our simulation shows that thermal conductivity of pristine graphene has logarithmic divergence for the boundary length up to 2 pm. As compared with pristine graphene, thermal conductivity of graphene oxide can be reduced by a factor of 25 at low oxygen defect concentration. Moreover, we find that not only the concentration but also the configuration of the oxygen functional groups (e.g., hydroxyl, epoxide, and ether) has significant influence on the thermal conductivity. Through phonon mode analysis, phonon defect scattering as well as phonon localization are mainly responsible for the conspicuous reduced thermal conductivity. The simulation results have provided fundamental insight on how to precisely control thermal property of graphene oxide for thermal management and thermoelectric applications.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Measuring Eco-Efficiency of Agriculture in China

Eco-efficiency is a tool for sustainability analysis that indicates how to carry out economic activities effectively. This paper assesses agricultural eco-efficiency using data envelopment analysis (DEA) and the Theil index approach. Using basic data of 31 provinces in China during 2003–2013, we analyzed the agricultural eco-efficiency development level and spatial pattern in China. The results show that the agricultural eco-efficiency of only four provinces has been relatively efficient in the entire study period, namely, Zhejiang, Hainan, Chongqing, and Tibet. The results also show that agricultural eco-efficiency was higher mainly in south of the Qinling Mountains-Huaihe River Line and north of the Yangtze River area, that agricultural eco-efficiency is mainly affected by pure technical efficiency, and that highly efficient areas are mainly concentrated in the densely populated areas, i.e., the economic developed areas (except Tibet). The Theil index results show that the agricultural eco-efficiency difference weakened between provinces in China, as did western and northeast regions, but eastern and central regions show a slight upward trend

Sustainability Assessment of Solid Waste Management in China: A Decoupling and Decomposition Analysis

As the largest solid waste (SW) generator in the world, China is facing serious pollution issues induced by increasing quantities of SW. The sustainability assessment of SW management is very important for designing relevant policy for further improving the overall efficiency of solid waste management (SWM). By focusing on industrial solid waste (ISW) and municipal solid waste (MSW), the paper investigated the sustainability performance of SWM by applying decoupling analysis, and further identified the main drivers of SW change in China by adopting Logarithmic Mean Divisia Index (LMDI) model. The results indicate that China has made a great achievement in SWM which was specifically expressed as the increase of ISW utilized amount and harmless disposal ratio of MSW, decrease of industrial solid waste discharged (ISWD), and absolute decoupling of ISWD from economic growth as well. However, China has a long way to go to achieve the goal of sustainable management of SW. The weak decoupling, even expansive negative decoupling of ISW generation and MSW disposal suggests that China needs timely technology innovation and rational institutional arrangement to reduce SW intensity from the source and promote classification and recycling. The factors of investment efficiency and technology are the main determinants of the decrease in SW, inversely, economic growth has increased SW discharge. The effects of investment intensity showed a volatile trend over time but eventually decreased SW discharged. Moreover, the factors of population and industrial structure slightly increased SW