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Facile construction of high-energy Li-ion batteries (LIBs) anode materials with robust heterostructure remains great challenges, especially for the fine integration of active materials with conductive carbon. Here, vertically aligned mixed-phase CoO/Co3O4 nanosheets anchored on wrinkled graphene (CoO/Co3O4/Gra) are controllably synthesized with the assistance of water-removable NaCl-templates through facile freeze-drying and calcination processes. In-depth investigations disclose that the wrinkled graphene induces the bonding with nucleating precursors, and the nanosheets vertically grow along the crystal planes of multilevel-NaCl. The as-formed mesoporous nanosheets-on-network structure endows the hybrids with efficient exposure of mixed-phase CoO/Co3O4 active sites and rapid charge-transfer channels. And the multiple composites can integrate the advantages of their long complements and fully exert their synergistic effects to solve the problems of the single metal oxide electrode. Furthermore, the electrochemical performance of hierarchically mesoporous architecture is beyond that of the single individual structure on account of the sufficient electrode/electrolyte interfaces, rapid Li+ diffusion and electron conduction, and stable structural integrity upon cycling. Accordingly, the capacitive kinetic of Li-storage behaviors is greatly enhanced by these synergistic effects. Serving as a LIBs anode material, the mesoporous CoO/Co3O4/Gra-4 hybrid yields superior reversible capacity (1390 mAh g−1 at 0.1 A g−1), high rate performance (1130 mAh g−1 at 0.2 A g−1), and impressive cycling stability (811 mAh g−1 after 500 cycles at 1 A g−1). This work may inspire the design of high-performance electrodes with advanced 3D hierarchical structures.

Composite material of NiO/CNTs consisting of two-dimensional porous NiO nanosheets threaded by carbon nanotubes was prepared by thermal treatment of Ni(OH) 2 /CNTs obtained from an in-situ hydro-thermal method. The introduction of CNTs during the synthesis processes can effectively prevented the aggregations of NiO nanosheets, and form interpenetrated composite structure. Therefore, porous NiO nanoflakes are threaded by CNTs, leading to the formation of the lightweight composite with different NiO loadings. The as-prepared NiO/CNTs composite is highly porous, effective for microwave absorption. The minimum reflection loss reaches −25.4 dB when the NiO loading is 85 wt% with thickness of 2.0 mm at 10 GHz. This composite material is expected to be a promising candidate as microwave absorbing materials.

Hollow carbon nanospheres (HCNs) with tunable sizes have been successfully prepared by the calcination of hollow copolymer nanospheres. Our findings indicate that compared to the counterpart solid carbon particle, HCNs all achieve substantially enhanced microwave absorption, suggesting that hollow structure plays an important role during microwave absorption. Moreover, further investigation on the effect of different HCNs sizes upon microwave absorption has been conducted. It is found that HCNs with an outer diameter of ∼70 nm and inner diameter of ∼30 nm exhibit the champion EM absorption performance, a minimum reflection loss (RL) of −50.8 dB at 13.5 GHz with a thickness of 1.9 mm, along with the corresponding bandwidth of RL less than −10 dB (90% absorption) covering 4.8 GHz. Notably, such excellent microwave absorption performance, probably as a result of well-matched impedance together with multiple reflection induced by the distinctive hollow structure, demonstrates HCNs to be one of the most competitive carbon-based absorbers to date. More importantly, this study provides an effective strategy to tune the microwave performance via tailoring the sizes of HCNs.

The formation of bis-hexahapto bonds between graphitic surfaces can electronically interconnect the surfaces of carbon materials containing the polybenzenoid ring system and increase the conductivity without introducing a strong perturbation to the in-plane electronic structure. In this paper, we report the use of organometallic chemistry to interconnect the surfaces of small scale graphene nanoplatelets by using a variety of metals and photochemically activated organometallic reagents.

A novel adsorbent based on zeolitic imidazolate framework-67 (ZIF-67, a sort of metal-organic framework) modified bacterial cellulose/chitosan (BC/CH) composite aerogel was prepared through a facile method combining physical mixture, in situ synthesis, and lyophilization. The water stability of CH aerogel was improved by incorporating BC nanofibers instead of using environmentally unfriendly chemical crosslinking agent. The loading rate of ZIF-67 was as high as 46.1% and the BET specific surface area of ZIF-67/BC/CH aerogel reached to 268.7 m2 g−1, which was much larger than that of BC/CH aerogel (8.4 m2 g−1). The as-prepared ZIF-67/BC/CH aerogel was employed to remove heavy metal ions and organic dye in aqueous solution. The adsorption capacities of the composite aerogel for Cu2+ and Cr6+ were 200.6 mg g−1 and 152.1 mg g−1, respectively. Moreover, the adsorption mechanism was investigated by X-ray photoelectron spectroscopy (XPS). Besides, the aerogel also showed almost 100% of removal rate toward active red X-3B through one time of adsorption. Consequently, the ZIF-67/BC/CH aerogel, as a novel and high efficient adsorbent, has a good application potential for wastewater treatment.

Flexible graphite nanoplatelets (GNPs)–copper nanowires (Cu NWs) composites of a sandwich-like structure were prepared by a simple filtration method. Cu NWs were sandwiched between GNPs films (G/NWs/G). The sandwiched structure results in conductivity up to 3.18 × 105 S m−1, higher than the reported graphene based papers and bulk graphite. The performance of the sandwiched papers is further improved to 8.65 × 105 S m−1 through mechanical pressing. Compared to the pure Cu NWs film, the sandwiched composite is oxidation resistant and stable in air, thus promising as candidates for high performance flexible electronics.

We consider the covalent chemistry of the carbon allotropes with an emphasis on the newest member—graphene. We focus on the effect of such chemistry on the geometric and electronic structure of the functionalized materials and the way in which the conjugation is modified by such processes. We conclude that there are two limiting cases: (a) Conventional addition chemistry leading to the formation of σ-bonds to the graphitic surface in which there is full rehybridization of the derivatized carbon atoms from sp 2 to sp 3 ; thus these carbon atoms are effectively removed from conjugation and from the electronic band structure (referred to as destructive rehybridization). (b) Covalent chemisorption with formation of an organometallic hexahapto-metal bond that largely preserves the graphitic band structure (constructive rehybridization) and accompanies the formation of bis-hexahapto-metal bonds such as those in (η 6 -SWNT)Cr(η 6 -SWNT) which serve to interconnect adjacent graphitic surfaces and significantly reduces the internanotube junction resistance in SWNT networks. The formation of η 2 di-hapto bonds represent an intermediate case of covalent chemistry and is known to be important in carbon nanotubes and particularly the fullerenes but this situation has been treated in detail in previous publications.

Single-walled carbon nanotube (SWNT) thin films provide a unique platform for the development of electronic and photonic devices because they combine the advantages of the outstanding physical properties of individual SWNTs with the capabilities of large area thin film manufacturing and patterning technologies. Flexible SWNT thin film based field-effect transistors, sensors, detectors, photovoltaic cells, and light emitting diodes have been already demonstrated, and SWNT thin film transparent, conductive coatings for large area displays and smart windows are under development. While chirally pure SWNTs are not yet commercially available, the marketing of semiconducting (SC) and metallic (MT) SWNTs has facilitated progress toward applications by making available materials of consistent electronic structure. Nevertheless the electrical transport properties of networks of separated SWNTs are inferior to those of individual SWNTs. In particular, for semiconducting SWNTs, which are the subject of this Account, the electrical transport drastically differs from the behavior of traditional semiconductors: for example, the bandgap of germanium (E = 0.66 eV) roughly matches that of individual SC-SWNTs of diameter 1.5 nm, but in the range 300-100 K, the intrinsic carrier concentration in Ge decreases by more than 10 orders of magnitude while the conductivity of a typical SC-SWNT network decreases by less than a factor of 4. Clearly this weak modulation of the conductivity hinders the application of SC-SWNT films as field effect transistors and photodetectors, and it is the purpose of this Account to analyze the mechanism of the electrical transport leading to the unusually weak temperature dependence of the electrical conductivity of such networks. Extrinsic factors such as the contribution of residual amounts of MT-SWNTs arising from incomplete separation and doping of SWNTs are evaluated. However, the observed temperature dependence of the conductivity indicates the presence of midgap electronic states in the semiconducting SWNTs, which provide a source of low-energy excitations, which can contribute to hopping conductance along the nanotubes following fluctuation induced tunneling across the internanotube junctions, which together dominate the low temperature transport and limit the resistivity of the films. At high temperatures, the intrinsic carriers thermally activated across the bandgap as in a traditional semiconductor became available for band transport. The midgap states pin the Fermi level to the middle of the bandgap, and their origin is ascribed to defects in the SWNT walls. The presence of such midgap states has been reported in connection with scanning tunneling spectroscopy experiments, Coulomb blockade observations in low temperature electrical measurements, selective electrochemical deposition imaging, tip-enhanced Raman spectroscopy, high resolution photocurrent spectroscopy, and the modeling of the electronic density of states associated with various defects. Midgap states are present in conventional semiconductors, but what is unusual in the present context is the extent of their contribution to the electrical transport in networks of semiconducting SWNTs. In this Account, we sharpen the focus on the midgap states in SC-SWNTs, their effect on the electronic properties of SC-SWNT networks, and the importance of these effects on efforts to develop electronic and photonic applications of SC-SWNTs.

We spectroscopically analyze the effect of e-beam deposition of lanthanide metals on the electronic structure and conductivities of films of semiconducting (SC) single-walled carbon nanotubes (SWNTs) in high vacuum. We employ near-infrared and Raman spectroscopy to interpret the changes in the electronic structure of SWNTs on exposure to small amounts of the lanthanides (Ln = Sm, Eu, Gd, Dy, Ho, Yb), based on the behavior of the reference metals (M = Li, Cr) which are taken to exemplify ionic and covalent bonding, respectively. The analysis shows that while the lanthanides are more electropositive than the transition metals, in most cases they exhibit similar conductivity behavior which we interpret in terms of the formation of covalent bis-hexahapto bonds [(η(6)-SWNT)M(η(6)-SWNT), where M = La, Nd, Gd, Dy, Ho]. However, only M = Eu, Sm, Yb show the continually increasing conductivity characteristic of Li, and this supports our contention that these metals provide the first examples of mixed covalent-ionic bis-hexahapto bonds [(η(6)-SWNT)M(η(6)-SWNT), where M = Sm, Eu, Yb].

Boron nitride nanosheets (BNNS) hold the similar two-dimensional structure as graphene and unique properties complementary to graphene, which makes it attractive in application ranging from electronics to energy storage. The exfoliation of boron nitride (BN) still remains challenge and hinders the applications of BNNS. In this work, the preparation of BNNS has been realized by a shear-assisted supercritical CO2 exfoliation process, during which supercritical CO2 intercalates and diffuses between boron nitride layers, and then the exfoliation of BN layers is obtained in the rapid depressurization process by overcoming the van der Waals forces. Our results indicate that the bulk boron nitride has been successfully exfoliated into thin nanosheets with an average 6 layers. It is found that the produced BNNS is well-dispersed in isopropyl alcohol (IPA) with a higher extinction coefficient compared with the bulk BN. Moreover, the BNNS/epoxy composite used as thermal interface materials has been prepared. The introduction of BNNS results in a 313% enhancement in thermal conductivity. Our results demonstrate that BNNS produced by supercritical CO2 exfoliation show great potential applications for heat dissipation of high efficiency electronics.

To determine the type and frequency of SCN1A deletions and duplications among patients with Dravet syndrome (DS).For DS patients in which no mutations of the SCN1A gene were detected by PCR-DNA sequencing, SCN1A deletions and duplications were detected by multiplex ligation-dependent probe amplification (MLPA).In 680 DS patients, 489 had SCN1A mutations identified by PCR-DNA sequencing. In 191 patients who were negative for the SCN1A PCR-DNA sequencing, 15 (15/191, 7.9%) were detected with heterozygous SCN1A deletions or duplications, which included 14 (14/15, 93.3%) SCN1A deletions and 1 SCN1A duplication. There were 13 types of mutations, including whole SCN1A deletions in 3 patients, partial SCN1A deletions in 11 patients and partial SCN1A duplications in one patient. By testing the parents, 14 mutations were found to be de novo. For the remaining case, no SCN1A deletion or duplication was found in the mother, while the father was not available.Approximately 8% of Chinese patients who were negative for SCN1A mutation by PCR-sequencing have SCN1A deletions or duplications. The MLPA analysis should be considered as an important strategy for such patients. SCN1A deletions are more common than SCN1A duplications among DS patients, and the most common types are whole SCN1A deletions. The majority of SCN1A deletions or duplications are de novo.

This paper proposes an improved Preference Ranking Organization Method for Enrichment Evaluations II method based on Axiomatic Fuzzy Sets (AFS). With AFS, the preference functions of alternatives can be easily decided by the ranking and difference degrees of performance values on each attribute. Furthermore, the method considers the objective weights of importance of the attributes as well as the subjective preferences of the decision maker to decide the integrated weights of importance of the attributes. In case study, the evaluation of the industrial economic benefit of 16 provinces or municipalities of China is used to demonstrate the performance of the proposed method. The ranking results show that the whole evaluating procedure is feasible and effective.

With the advent of many different forms of graphene (in addition to the long standing interest in fullerenes and carbon nanotubes), the characterization of carbon materials and their degree of conjugation is a particularly important topic in carbon science. We report the application of absorption spectroscopy and conductivity measurements to graphene derivatives and related carbon materials. Reduced graphene oxide (RGO) has been widely studied as a promising material for graphene applications because of its processability, and the same considerations apply to graphene functionalized with octadecylamine (ODA). This study utilizes a direct chemical modification of GO with ODA in the presence of dicyclohexylcarbodiimide to partially regenerate the graphene π-conjugation while producing a material (ODA-G) with excellent solubility in organic solvents. We show that the ODA-G exhibits optical absorptions, which are much stronger than those of GO, and comparable to liquid phase exfoliated graphene and reduced graphene oxide; the optical analysis is unified by the development of an analytical relationship between solid state absorption coefficients and solution state extinction coefficients, which allows the direct comparison of the electronic absorption spectroscopy of films and solutions of carbon materials. We further benchmark the regeneration of the graphenic structure in ODA-G with electrical conductivity measurements.

A series of interesting questions will be proposed and tried to be answered in this paper such as: Is there a limit of disaster-bearing capability in a region human-environment system (HES) when the system is hit by an extreme flood disaster? If so, what does it mean and how can it be explained? An assumption, naming the regional limit of flood-bearing capability (LFBC), is suggested and proved to respond these questions in this study. The LFBC model consists of three factors, namely, the disaster-causing factor (DCF), disaster-bearing factor (DBF) and disaster-regulating factor (DRF). The DCF can be selected from the cause analysis of flood, the DBF can be extracted from analysis of flood risk and vulnerability, and the DRF is responding to the analysis of flood risk management and measures. The logical relations among the three factors are determined by the analysis of flood inundation-loss models. The limit of disaster-bearing capability in regional HES is introduced by the principles of threshold analysis in terms of large-scale system theory, and can be expressed as the regional inundated depth or the amount of water in a flood. The LFBC model is built up following this idea, and approaches of its application are stated with the support of remote sensing (RS) and geographical information system (GIS). Substantial changes in terms of system succession, such as reservoir resettlement, population migration and land use pattern change, would occur only when extreme flood beyond its limit of disaster-bearing capability in a regional HES. Otherwise, the difference can be use to measures the damage conditions. Combining the occurrence probability of extreme flood, the LFBC model could be used to provide the data support for flood damage assessment, regional disaster control and reduction countermeasures, and regional development planning.

In this Perspective, we present an overview of recent fundamental studies on the nature of the interaction between individual metal atoms and metal clusters and the conjugated surfaces of graphene and carbon nanotube with a particular focus on the electronic structure and chemical bonding at the metal–graphene interface. We discuss the relevance of organometallic complexes of graphitic materials to the development of a fundamental understanding of these interactions and their application in atomtronics as atomic interconnects, high mobility organometallic transistor devices, high-frequency electronic devices, organometallic catalysis (hydrogen fuel generation by photocatalytic water splitting, fuel cells, hydrogenation), spintronics, memory devices, and the next generation energy devices. We touch on chemical vapor deposition (CVD) graphene grown on metals, the reactivity of its surface, and its use as a template for asymmetric graphene functionalization chemistry (ultrathin Janus discs). We highlight som...

In this Account, we discuss the chemistry of graphitic materials with particular reference to three reactions studied by our research group: (1) aryl radical addition, from diazonium precursors, (2) Diels-Alder pericyclic reactions, and (3) organometallic complexation with transition metals. We provide a unified treatment of these reactions in terms of the degenerate valence and conduction bands of graphene at the Dirac point and the relationship of their orbital coefficients to the HOMO and LUMO of benzene and to the Clar structures of graphene. In the case of the aryl radical addition and the Diels-Alder reactions, there is full rehybridization of the derivatized carbon atoms in graphene from sp(2) to sp(3), which removes these carbon atoms from conjugation and from the electronic band structure of graphene (referred to as destructive rehybridization). The radical addition process requires an electron transfer step followed by the formation of a σ-bond and the creation of a π-radical in the graphene lattice, and thus, there is the potential for unequal degrees of functionalization in the A and B sublattices and the possibility of ferromagnetism and superparamagnetism in the reaction products. With regard to metal functionalization, we distinguish four limiting cases: (a) weak physisorption, (b) ionic chemisorption, in which there is charge transfer to the graphitic structure and preservation of the conjugation and band structure, (c) covalent chemisorption, in which there is strong rehybridization of the graphitic band structure, and (d) covalent chemisorption with formation of an organometallic hexahapto-metal bond that largely preserves the graphitic band structure (constructive rehybridization). The constructive rehybridization that accompanies the formation of bis-hexahapto-metal bonds, such as those in (η(6)-SWNT)Cr(η(6)-SWNT), interconnects adjacent graphitic surfaces and significantly reduces the internanotube junction resistance in single-walled carbon nanotube (SWNT) networks. The conversion of sp(2) hybridized carbon atoms to sp(3) can introduce a band gap into graphene, influence the electronic scattering, and create dielectric regions in a graphene wafer. However, the organometallic hexahapto (η(6)) functionalization of the two-dimensional (2D) graphene π-surface with transition metals provides a new way to modify graphitic structures that does not saturate the functionalized carbon atoms and, by preserving their structural integrity, maintains the delocalization in these extended periodic π-electron systems and offers the possibility of three-dimensional (3D) interconnections between adjacent graphene sheets. These structures may find applications in interconnects, 3D-electronics, organometallic catalysis, atomic spintronics and in the fabrication of new electronic materials.

Graphite nanoplatelets (GNPs) were reacted with transition metal (M) carbonyls followed by annealing and compaction to remove the CO ligands and form bis-hexahapto bonds between the GNP surfaces. The M-GNP films (M = Cr, W, Mo) were characterized with Raman spectroscopy and conductivity measurements. It was observed that interconnection of the graphitic faces of GNPs by bis-hexahapto metal coordination resulted in a decrease of electrical conductivity. The complexes offer promise as catalysts and in the fabrication of new 3-D electronic materials.

We report the preparation of organometallic side-wall complexes of single-walled carbon nanotubes (SWNTs) under conditions, which allow the study of both mono- and bis-hexahapto SWNT coordination compounds [(η6-SWNT)Cr(CO)3, (η6-SWNT)Cr(η6-C6H6), (η6-SWNT)2Cr]. The results are interpreted in terms of exohedral and endohedral binding of chromium to the SWNT sidewalls and ligand competition reactions suggest that endohedral binding provides a very stable and kinetically inert mode of organometallic bonding. We demonstrate that the electrical conductivity of SWNT thin films are significantly enhanced by side-wall bonding to Group 6 transition metals (M = Cr, Mo, and W), which serve to reduce the inter-carbon nanotube junction electrical resistance by the formation of SWNT interconnects [(η6-SWNT)2M].

A high-sensitivity mechano-luminescent sensor was fabricated on the basis of piezoelectric/electroluminescent composites. The working principle of this mechano-luminescent sensor was elucidated by analyzing the relationship between the piezoelectric-induced charges and the electroluminescent effects. When a stress is applied on the piezoelectric layer, electrical charges will be induced at both the top and bottom sides of the piezoelectric layer. The induced electrical charges will lead to a light output from the electroluminescent layer, thus producing a mechano-luminescence effect. By increasing the vibration strength or frequency applied, the mechano-luminescence output can be obviously enhanced. Mechano-luminescence sensors have potential in smart stress-to-light devices, such as foot-stress-distribution-diagnosis systems and dynamic-load-monitors for bridge hanging cables.

Rabbit hemorrhagic disease was described in China in 1984 and can cause hemorrhagic necrosis of the liver within two or three days after infection. The etiological agent, rabbit hemorrhagic disease virus (RHDV), belongs to the Lagovirus genus in the Caliciviridae family. Compared to other calicivirus, such as rNV and SMSV, the structure of Lagovirus members is not well characterized. In this report, structures of two types of wild RHDV particles, the intact virion and the core-like particle (CLP), were reconstructed by cryo-electron microscopy at 11 &0A and 17 &0A, respectively. This is the first time the 3D structure of wild caliciviruses CLP has been provided, and the 3D structure of intact RHDV virion is the highest resolution structure in Lagovirus. Comparison of the intact virion and CLP structures clearly indicated that CLP was produced from the intact virion with the protrusion dissociated. In contrast with the crystal structures of recombinant Norovirus and San Miguel sea lion virus, the capsomers of RHDV virion exhibited unique structural features and assembly modes. Both P1 and P2 subdomains have interactions inside the AB capsomer, while only P2 subdomains have interaction inside CC capsomer. The pseudo atomic models of RHDV capsomers were constructed by homology modeling and density map fitting, and the rotation of RHDV VP60 P domain with respect to its S domain, compared with SMSV, was observed. Collectively, our cryo-electron microscopic studies of RHDV provide close insight into the structure of Lagovirus, which is important for functional analysis and better vaccine development in the future.

Encapsulation of sulfur in HiPCO-SWNTs leads to large changes in the Raman spectra with the appearance of new peaks at 319, 395, and 715 cm–1 which originate from the sulfur species within the SWNTs, while the high frequency SWNT bands (ν > 1200 cm–1) are decreased in intensity. The encapsulated species also shifts the near-IR interband electronic transitions to lower energy by more than 10%. These effects seem to originate with the van der Waals interaction of the confined sulfur species with the walls of the SWNTs which are not expected to be significant in the case of the previously studied large diameter SWNTs. We suggest that sulfur in the small diameter SWNTs exists as a helical polymeric sulfur chain that enters the SWNT interior in the form of S2 (3Σg–) molecules which undergo polymerization to linear diradicals. Fil: Li, Guanghui. University of California; Estados Unidos Fil: Fu, Chengyin. University of California; Estados Unidos Fil: Oviedo, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. University of California; Estados Unidos Fil: Chen, Mingguang. University of California; Estados Unidos Fil: Tian, Xiaojuan. University of California; Estados Unidos Fil: Bekyarova, Elena. University of California; Estados Unidos Fil: Itkis, Mikhail. University of California; Estados Unidos Fil: Wong, Bryan. University of California; Estados Unidos Fil: Guo, Juchen. University of California; Estados Unidos Fil: Haddon, Robert. University of California; Estados Unidos

The in-plane alignment of graphite nanoplatelets (GNPs) in thin thermal interface material (TIM) layers suppresses the though-plane heat transport thus limiting the performance of GNPs in the geometry normally required for thermal management applications. Here we report a disruption of the GNP in-plane alignment by addition of spherical microparticles. The degree of GNP alignment was monitored by measurement of the anisotropy of electrical conductivity which is extremely sensitive to the orientation of high aspect ratio filler particles. Scanning Electron Microscopy images of TIM layer cross-sections confirmed the suppression of the in-plane alignment. The hybrid filler formulations reported herein resulted in a synergistic enhancement of the through-plane thermal conductivity of GNP/Al2O3 and GNP/Al filled TIM layers confirming that the control of GNP alignment is an important parameter in the development of highly efficient GNP and graphene-based TIMs.

The hesitant fuzzy linguistic term sets(HFLTSs) can be used to represent an expert's hesitant preferences when assessing the membership of an element. By integrating the strength of HFLTSs in dealing with uncertainty and vagueness and the merit of grey relation analysis in modeling multi-criteria decision making, a gray relevance analysis method based on HFLTSs is proposed in this paper. The solving procedure is as follows, (i) the weights of criteria are determined by the group decision making models based on AHP; (ii) using the weighted grey relational degree between the reference data sequence and optimal data sequence to result the ranking order for all alternatives; (iii) An illustrative example is provided to verify the proposed approach and to demonstrate its practicality and effectiveness.

Covalent chemistry exerts characteristic changes to the geometric and electronic structures of the carbon allotropes associated with modification of the conjugation. There are two limiting cases: (a) conventional addition chemistry leading to the formation of σ-bonds to the graphitic surface in which there is full rehybridization of the derivatized carbon atoms from sp2 to sp3; in this case the carbon atoms are removed from conjugation (destructive rehybridization) and (b) covalent chemisorption with formation of an organometallic hexahapto-metal bond that largely preserves the graphitic band structure (constructive rehybridization). 1, 2 We focus our discussion on the organometallic chemistry of the carbon allotropes and the possibility to electronically interconnect graphitic surfaces by means of covalent bonding. This mode of functionalization allows the formation of atomic scale interconnects that consist of bis-hexahapto-metal-bonds between benzenoid ring systems and it may be used to increase the dimensionality of the electronic structure of the materials leading to enhanced conductivity. We will discuss the effect of bis-hexahapto bond formation on the electronic properties of percolating networks of single walled carbon nanotubes, small scale graphite nanoplatelets and graphene. 1. Bekyarova, E.; Sarkar, S.; Wang, F.; Itkis, M. E.; Kalinina, I.; Tian, X.; Haddon, R. C., Effect of Covalent Chemistry on the Electronic Structure and Properties of Carbon Nanotubes and Graphene. Acc. Chem. Res. 2013, 46, 65-76. 2. Bekyarova, E.; Niyogi, S.; Sarkar, S.; Tian, X.; Chen, M.; Moser, M. L.; Ayub, K.; Mitchell, R. H.; Haddon, R. C., Stereochemical Effect of Covalent Chemistry on the Electronic Structure and Properties of the Carbon Allotropes and Graphene Surfaces. Synth. Met. 2015, 210, 80-84.

The formation of covalent bonds to single-walled carbon nanotube (SWNT) or graphene surfaces usually leads to a decrease in the electrical conductivity and mobility as a result of the structural rehybridization of the functionalized carbon atoms from sp(2) to sp(3). In the present study, we explore the effect of metal deposition on semiconducting (SC-) and metallic (MT-) SWNT thin films in the vicinity of the percolation threshold and we are able to clearly delineate the effects of weak physisorption, ionic chemisorption with charge transfer, and covalent hexahapto (η(6)) chemisorption on these percolating networks. The results support the idea that for those metals capable of forming bis-hexahapto-bonds, the generation of covalent (η(6)-SWNT)M(η(6)-SWNT) interconnects provides a conducting pathway in the SWNT films and establishes the transition metal bis-hexahapto organometallic bond as an electronically conjugating linkage between graphene surfaces.

We report the response of the electrical conductivity of semiconducting single-walled carbon nanotube (SWNT) thin films on exposure to metal vapors of the early lanthanides under high vacuum conditions. We attribute the strongly enhanced conductivities observed on deposition of samarium and europium to charge transfer from the metals to the SWNT backbone, thereby leading to the first examples of mixed covalent-ionic bis-hexahapto bonds [(η(6)-SWNT)M(η(6)-SWNT), where M = Sm, Eu].

In this Perspective, we present an overview of recent fundamental studies on the nature of the interaction between individual metal atoms and metal clusters and the conjugated surfaces of graphene and carbon nanotube with a particular focus on the electronic structure and chemical bonding at the metal–graphene interface. We discuss the relevance of organometallic complexes of graphitic materials to the development of a fundamental understanding of these interactions and their application in atomtronics as atomic interconnects, high mobility organometallic transistor devices, high-frequency electronic devices, organometallic catalysis (hydrogen fuel generation by photocatalytic water splitting, fuel cells, hydrogenation), spintronics, memory devices, and the next generation energy devices. We touch on chemical vapor deposition (CVD) graphene grown on metals, the reactivity of its surface, and its use as a template for asymmetric graphene functionalization chemistry (ultrathin Janus discs). We highlight som...

Thermal interface materials (TIMs) are crucial components of high density electronics and the high thermal conductivity of graphite makes this material an attractive candidate for such applications. We report an investigation of the in-plane and through-plane electrical and thermal conductivities of thin thermal interface layers of graphite nanoplatelet (GNP) based composites. The in-plane electrical conductivity exceeds its through-plane counterpart by three orders of magnitude, whereas the ratio of the thermal conductivities is about 5. Scanning electron microscopy reveals that the anisotropy in the transport properties is due to the in-plane alignment of the GNPs which occurs during the formation of the thermal interface layer. Because the alignment in the thermal interface layer suppresses the through-plane component of the thermal conductivity, the anisotropy strongly degrades the performance of GNP-based composites in the geometry required for typical thermal management applications and must be taken into account in the development of GNP-based TIMs.

Chemically modified single-walled carbon nanotubes (SWNTs) with varying degrees of functionalization were utilized for the fabrication of SWNT thin film catalyst support layers (CSLs) in polymer electrolyte membrane fuel cells (PEMFCs), which were suitable for benchmarking against the US DOE 2017 targets. Use of the optimum level of SWNT -COOH functionality allowed the construction of a prototype SWNT-based PEMFC with total Pt loading of 0.06 mg(Pt)/cm²--well below the value of 0.125 mg(Pt)/cm² set as the US DOE 2017 technical target for total Pt group metals (PGM) loading. This prototype PEMFC also approaches the technical target for the total Pt content per kW of power (0.125 g(PGM)/kW) at cell potential 0.65 V: a value of 0.15 g(Pt)/kW was achieved at 80°C/22 psig testing conditions, which was further reduced to 0.12 g(Pt)/kW at 35 psig back pressure.

The Geostationary Ocean Color Imager (GOCI) can produce good ocean colour products in the open sea. However, an atmospheric correction problem continues to occur for turbid coastal water environment monitoring. In this communication, a regional atmospheric correction method based on an artificial neural network (ANN) model has been proposed. The ANN model was built according to differences in the spatial and radiometric characteristics between the Medium Resolution Imaging Spectrometer (MERIS) and GOCI, with 3000 pixels of the top-of-atmosphere (TOA) reflectance of seven GOCI images from 2011 to 2012 above turbid water used as the inputs and coinciding validated remote-sensing reflectance (Rrs) of MERIS 1 used as the outputs. Subsequently, the water-leaving reflectance of GOCI in turbid coastal water areas of the Bohai Sea was derived. Compared with the products produced by the standard GOCI Data Processing System (GDPS Version 1.3), the Rrs retrieved according to the proposed method showed a significant improvement in spatial pattern. Although the ANN model displayed a degree of difficulty in representing high water-leaving reflectance values, a comparison with three in situ measurements collected on 11 November 2011 in the study area showed encouraging results. The results suggest that the ANN method can be used for atmospheric correction process in turbid waters without requiring numerous in situ measurements.

Ship classification in high resolution SAR satellite imagery is a hotspot and preceding problem in SAR applications. According to the different features of cargo ship, oil tanker and container ship in high resolution SAR images, we propose a method to extract structure feature of three civilian ship types. Firstly, the morphological pre-processing is used for sidelobe suppression. Secondly, the main axes are extracted using Hough Transform; the Minimum Enclosing Rectangle(MER) of ship is obtained and rotated to the direction of principal axes, then it is adjusted to fit the ship well. Finally, the scattering properties of different ship types are analyzed. The result shows that this method has good performance in feature extraction of ships in high resolution SAR imagery.

Classification is one of the most popular data mining techniques applied to many scientific and industrial problems. Recently, fuzzy association rule has been extensively studied in classification. In this paper, a new classification model is proposed, which is based on interpretable fuzzy association rules and automatic generating membership functions. In addition,a modified algorithm for classification is presented. The results on five data sets indicate that the proposed classifier can be regarded as an accurate and effective classification technique. Compared with other classification approaches and fuzzy logics, a relative error rate is lower in our results.

We demonstrate the ability of first row transition metals to form electrically conducting interconnects between semiconducting single-walled carbon nanotubes (SWNTs) by constructive rehybridization between sidewall benzene rings as a result of the formation of bis-hexahapto-metal-bonds [(η6-SWNT)M(η6-SWNT)], which bridge adjacent SWNTs. Metal deposition on SWNT films enhances the conductivity by three distinct mechanisms: physisorption of gold leads to the formation of a non-interacting gold film and a monotonic conductivity increase; ionic chemisorption of lithium strongly increases the conductivity due to charge transfer to the SWNTs; covalent chemisorption of first row transition metals leads to an abrupt change in conductivity due to formation of (η6-SWNT)M(η6-SWNT) interconnects.

Clear magneto-light output is obtained from a fabricated three-phase composite of magnetostrictive, piezoelectric, and electroluminescent materials. Electrical charges, attributable to the magnetoelectric effect, are induced when a magnetic field is applied to the magnetostrictive/piezoelectric layers. These induced electrical charges result in a light signal emanating from the electroluminescent layer, thereby accomplishing a magneto-light effect. Increasing the strength of the applied ac magnetic field or the number of series-connected piezoelectric layers produces an enhanced magneto-light output. The magneto-light composite has potential applications in magnetic resonance imaging, optical monitoring of magnetic fields, magnetic/light sensing, and transducer technologies.