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Currently, graphene films are expected to achieve real applications in various fields. However, the conventional synthesis methods still have intrinsic limitations, especially not being applicable on a surface with high curvature. Herein, an ultrafast synthesis method was developed for graphene and turbostratic graphite growth by a single subsecond pulse of microwaves generated by a household magnetron. We succeeded in growing high-quality around 10-layered turbostratic graphite in 0.16 s directly on the surface of an atomic force microscope probe and maintaining a tip curvature radius of less than 30 nm. The thus-produced probes showed high conductivity and tip durability. Moreover, turbostratic graphite film was also demonstrated to grow on the surface of dielectric Si flat substrates in a full coverage. Graphene can also grow on metallic Ni tips by this method. Our microwave ultrafast method can be used to grow high-quality graphene in a facile, efficient, and economical way.

Hydrogenated amorphous carbon (a-C:H) films are capable of providing excellent superlubricating properties, which have great potential serving as self-lubricating protective layer for mechanical systems in extreme working conditions. However, it is still a huge challenge to develop a-C:H films capable of achieving robust superlubricity state in vacuum. The main obstacle derives from the lack of knowledge on the influencing mechanism of deposition parameters on the films bonding structure and its relation to their self-lubrication performance. Aiming at finding the optimized deposition energy and revealing its influencing mechanism on superlubricity, a series of highly-hydrogenated a-C:H films were synthesized with appropriate ion energy, and systematic tribological experiments and structural characterization were conducted. The results highlight the pivotal role of ion energy on film composition, nanoclustering structure, and bonding state, which determine mechanical properties of highly-hydrogenated a-C:H films and surface passivation ability and hence their superlubricity performance in vacuum. The optimized superlubricity performance with the lowest friction coefficient of 0.006 coupled with the lowest wear rate emerges when the carbon ion energy is just beyond the penetration threshold of subplantation. The combined growth process of surface chemisorption and subsurface implantation is the key for a-C:H films to acquire stiff nanoclustering network and high volume of hydrogen incorporation, which enables a robust near-frictionless sliding surface. These findings can provide a guidance towards a more effective manipulation of self-lubricating a-C:H films for space application.

Carbon fiber reinforced composites (CFRP) are widely used in the aviation industry and other fields. During service, the surface of CFRP is vulnerable to impact and damage defects, which poses a threat to the safety of CFRP quality. The halogen lamp is used as the active heat source of the sample. Based on the built optical pulse thermography (OPT) test system, The sample with impact damage under long pulse excitation is studied. The thermal response of impact damage samples was collected by infrared camera A655sc. The original infrared image sequence is processed by pulse phase method (PPT), thermal signal reconstruction (TSR), and total harmonic distortion (THD). The results show that the signal-to-noise ratio (SNR) of Original images processed by PPT, TSR, and THD is improved, while the SNR of THD is significantly improved. More impact damage defects recognition effect is obtained by optical pulse thermography.

In this work, we designed three series of tribo-couples based on amorphous carbon films including GLC, DLC and PLC that were modified by graphene quantum dots (GQDs). The tribo-testing environment was controlled at harsh conditions (like heavy load and high speed) in dry nitrogen atmosphere using bare and film-coated bearing steel balls as counterbodies, respectively. Through the tribochemical interactions, the self-mated DLC system obtained a surperlubricity state (μ = 0.01). During the whole sliding, the contact surface of the upper counterfacing ball was covered by 2D-layered carbon and graphitic lubricants induced via structural transformation of GQDs. Meanwhile, the tribofilm of the disc wear track was composed of a silica-like SiOx boundary layer and a multicomponent mixed-layer induced by tribochemistry. Compared to the self-mated DLC system, the structural boundary enriched with SiOx compounds was not formed at the bottom region of the tribofilm for the bare steel system; meanwhile, the disc wear track was covered by a thicker tribofilm containing plenty of degraded GQDs. This inferred the fact that the formation of a nanostructured sliding interface was the key to realize superlubricity. These discoveries successfully afforded a lubrication mechanism of GQDs for solid lubricant in applications of engineering and industry.

Hydrogenated amorphous carbon (a-C:H) is subjected to abnormal high friction in ambient air, and the possibility to retain an ultra-low friction state remains as a great challenge. Here, nanodiamond and graphene were used as solid lubricants to improve the tribological properties of two representative types of a-C:H films with 20 at.% and 40 at.% hydrogen contents, respectively. The results emphasize the exceptionally synergetic lubrication effect of nanodiamond + graphene composite with a mass ratio of 1:1 and a solution-processed concentration of 0.1 mg/mL. An ultra-low friction coefficient of ∼0.02 was achieved for a-C:H (20 at.% H) film, and more strikingly, a dramatic reduction in COF from 0.52 to 0.07 was realized in a-C:H (40 at.% H) film. Meanwhile, the wear rates of the counterparts in both cases are significantly reduced in the presence of nano-lubricants. The lubricity mechanisms are mainly based on the in-situ growth of nanostructured tribolayers. The roles of a-C:H film bonding characteristic and the tribo-induced structural evolution of nano-lubricants in the build-up of anti-friction and wear-resistant tribolayers are discussed. These findings can enrich the understanding of surface modification pathways to a-C:H films via low-dimensional nano-lubricants and help to develop more adaptive and robust solid carbon films.

Graphene has many excellent optical, electrical and mechanical properties due to its unique two-dimensional structure. High-efficiency preparation of large area graphene film is the key to achieve its industrial applications. In this paper, an ultrafast quenching method was firstly carried out to flow a single pulse current through the surface of a Si wafer with a size of 10 mm × 10 mm for growing fully covered graphene film. The wafer surface was firstly coated with a 5-nm-thick carbon layer and then a 25-nm-thick nickel layer by magnetron sputtering. The optimum quenching conditions are a pulse current of 10 A and a pulse width of 2 s. The thus-prepared few-layered graphene film was proved to cover the substrate fully, showing a high conductivity. Our method is simple and highly efficient and does not need any high-power equipment. It is not limited by the size of the heating facility due to its self-heating feature, providing the potential to scale up the size of the substrates easily. Furthermore, this method can be applied to a variety of dielectric substrates, such as glass and quartz.

Background: Belonging to the ubiquitin-conjugating enzymes (E2s) family, UBE2V2 demonstrated a remarkable tumourigenic ability in many kinds of cancers. However, the interrelationship between UBE2V2 expression and morbidity of lung adenocarcinoma (LUAD) is still unknown. Methods: By using TCGA predictions and clinical tissue samples, we assessed the expression of UBE2V2 mRNA and protein in LUAD and analyzed its relationship with different clinicopathological factors as well as survival prognosis. Besides, we further studied the EMT signaling pathway that promotes LUAD metastasis and other phenotypic experiments by using lentivirus to transfect LUAD cells. Results: Our research results showed that compared with normal tissues, the expression of UBE2V2 mRNA and protein in LUAD was significantly increased (PConclusions: In summary, UBE2V2 might play an important role in the progression of LUAD.

RBM10 is the RNA-binding protein often absent or mutated in lung adenocarcinoma, rendering it as a potential biomarker or even therapeutic target to prolongate survival time. In this study, we investigated the involvement of RBM10 mutation in the pathogenesis and tumorigenesis of lung adenocarcinoma and identified the differentials in relative signal pathways, aiming to provide the new therapeutic approaches. By performing the systematic TCGA analysis, our results demonstrated that RBM10 mutation was identified in 6% lung adenocarcinoma patients, meanwhile 113 functional genes were identified as significant expression among these patients. Further gene ontology and KEGG analysis were employed to identify the most relative 10 genes and signal pathways. Moreover, four members of the 5-acyl-6, 7-dihydrothiophene [3, 2-c] pyridine (known as "ru-ski")-ru-ski 43 were identified as the potential drugs for RBM10 mutation lung adenocarcinoma therapy, investigated by the GDSC database. Meanwhile there were 157 genes that were more frequently mutated in the RBM10 mutation group than the wild-type group (p value

Graphene has emerged as one of the most promising solid lubricants owing to their exceptional lubricity. The atomically thin nature and its ability to conformally adsorb on the sliding surfaces provide unprecedented pathways for modifying the friction and wear behaviors of the mechanical moving parts. Here, the tribological responses of several representative tribo-couples including bare steel, diamond-like carbon and ceramic materials are investigated to explore the potentials of graphene as surface modifier. Specific emphasis is devoted to the graphene-induced reconstruction of the sliding interface and the growth mechanism of nanostructured tribofilms formed on the contact surface using high-resolution microscopic technique. The results reveal the unique properties of graphene regarding the friction reduction and wear protection irrespective of the types of counterpart materials, graphene-processed methods, dry or humid tests environments. Nevertheless, the interfacial features and the bonding characteristics of the tribofilms are diversified in each specific rubbing case, demonstrating the distinguished adaption capacity of graphene to the tribo-testing conditions. The present findings shed light on the lubrication phenomenon of graphene at the microscale and may provide useful design criterion for 2D-based solid lubricants.

Robust superlubricity of the disulphide-based film or diamond-like carbon (DLC) coating has been systematically investigated in relation to interfacial nanostructures and environmental atmospheres. Nevertheless, the frictional performances of the tribo-couple between them, especially the underlying mechanisms governing superlubricity are scarcely touched. In this study, we designed the periodically multilayered MoS2-Ag film based on ion beam assisted deposition (IBAD) and found a superior lubricating durability of the film with a superlow friction coefficient of 0.0065 triggered by DLC film under a load of 10 N in N2. The in-depth structural analysis on the contact areas of tribopairs were performed through Raman and high-resolution transmission electron microscopy (HRTEM). The results demonstrate that sliding-affected regions of the film generally undergo a deep amorphization transformation and the materials are transferred to counterfacing ball to form a multiphase tribofilm. The prevailing mechanisms emphasize that the superlubricious status highly depends on the synergistic effect from both the physicochemical properties of shear-induced tribofilm and the structural transformation of the MoS2-Ag surface by different contact mechanics and reconfiguration pathways. The findings shed light on the nature of tribochemical mechanisms of MoS2-Ag film and provide a new strategy to achieve macroscale superlubricity of the disulphide-related lubricants.

This paper reports the ferroelectricity in antiferromagnetic SmCrO3 with a reasonably large value of spontaneous electric polarization (70 μC/cm2 mC cm−2 at 50 K) based on the measurement of pyroelectric current. The experimental results showed that the temperature of the onset of polar order was evidently higher (about 220 K) than the Neel temperature (TN =197 K) in the magnetodielectric studies. The calculated magnetodielectric effect (MDE) value was explicitly negative with maximum | MDE | values of about 3.6% around 230 K. The absence of a convincing signature in MDE at antiferromagnetic ordering temperature TN indicated the absence of magnetoelectric coupling around this temperature regime. The results further confirmed that the onset of polar order can be attributed to the structural distortion, rather than the canted noncollinear magnetic structure.

Various ceramic composites of TbFexMn1-xO3 (x = 0, 0.25, 0.5, 0.75) were prepared by conventional solid-state reaction. The electrical properties such as dielectric constant, loss and resistivity have been studied as a function of the temperature from 77 to 400 K and the frequency from 0.1 to 1000 kHz. The XRD and SEM for these four types of materials show similar patterns with the increasing of the Fe concentration. Instead, the dielectric constant and loss for them will change dramatically in properties. The figures of all samples display two distinct semicircular arcs in the Nyquist plots at 300 K and all figures located at high frequency region are independent of the applied ac biases. By analyzing the values of the activation energy, it is found that the origin of the relaxation in dielectric loss is related to the changing of octahedral structure.

Onion-like carbon (OLC), spherical nanoparticles consisting of carbon shells, is capable of providing exceptional lubrication effects. Nevertheless, the underlying mechanism, especially the tribo-induced evolution of interfacial nanostructures and their correlation with the friction states, is not clear. In this work, OLC films with a thickness of ∼1 μm were synthesized by electrophoretic deposition on the mirror-polished stainless steel. The lubricity was evaluated by tailoring the sliding aspects including applied normal load, contact time, and counterface materials. It is found that the friction reduction level is highly dependent on the material transfer and transformation of the OLC surface and the physicochemical nature of the as-formed tribolayer in the contact areas. The subsurface of the OLC film always undergoes a deep amorphization transformation upon sliding. It is interesting to note that the tribolayer formed on the bare steel ball is mainly composed of highly ordered graphene-like nanoflakes derived from the sliding-induced degradation of OLC nanospheres. In comparison, the nanospherical carbon structure can be retained in the topmost subsurface of the tribolayer formed on the ceramic Si

The onion-like carbon (OLC) possesses a micro-spherical structure with a diameter of approximately 7 nm consisting of 0.35 nm-spaced carbon layers, and the OLC film is capable of providing excellent solid lubrication performances because of the high content of sp2-bonded carbon phase. However, the unfavorable durability severely restricts the lubrication application in practice. For the purpose of addressing this issue, heat treatment is employed to improve the lubrication robustness of the loose OLC film. The wear resistance was significantly improved with a duration of 60,000 sliding cycles at least when the OLC-coated samples were annealed at 600 °C in vacuum. Furthermore, the systematic analyses, particularly providing deep insights into the microstructural characterization, indicate that the structural reinforcement of OLC and the net-like adhering structures formed on the steel substrates annealed at specific temperature can effectively promote lubrication characteristics in two different stages. We propose that annealing treatment can improve the stability of micro-spherical OLC structures, thereby increasing the duration of lubrication. The evolution mechanism of OLC structures at the sliding interface is the key factor for maintaining the lubrication duration in dry contact.

Up to now, there have been many research studies that have revealed the unique phenomena of various materials encapsulated in a confined nano-sized space, such as in the interior of carbon nanotubes (CNTs). Confined in such a space several nanometers in size, these materials showed many different and interesting properties. However, the morphology and behaviors of these materials encapsulated in a comparatively bigger space, i.e., from tens of nanometers to microns, have been little investigated. In this work, carbon nanocones (CNCs), which are multilayered graphene-like nanomaterials with a hollow conical structure and an inner size varying continuously from several nanometers to micrometers, were used as the workhorse to investigate the nano-confinement effects on different scales. Gd acetate was adopted to be incorporated into the conical inner space of the CNCs. The corresponding Gd oxide, formed upon heating, showed a unique morphology and crystallization behavior in this sub-micron space. The confined Gd oxide was conical in shape, perfectly fitting the interior of the CNCs. Several crystallization orientations were often presented in the Gd oxide cone structure, and single crystallization was also observed located close to the apex of the CNCs. The crystal size of Gd oxide was over 100 nm, implying the effective scale of the confinement phenomenon between the CNCs and Gd oxide. Moreover, we further found that the Gd oxide cone retained its structure, instead of forming a spherical particle when it moved outward from the CNC driven by a high temperature, indicating the high stability of the conical Gd oxide nanocrystals.

Background Air pollution constitutes the major threat to human health, whereas their adverse impacts and underlying mechanisms of different particular matters are not clearly defined. Scope of review Ultrafine particles (UFPs) are high related to the anthropogenic emission sources, i.e. combustion engines and power plants. Their composition, source, typical characters, oxidative effects, potential exposure routes and health risks were thoroughly reviewed. Major conclusions UFPs play a major role in adverse impacts on human health and require further investigations in future toxicological research of air pollution. General significance Unlike PM 2.5 , UFPs may have much more impacts on human health considering loads of evidences emerging from particulate matters and nanotoxicology research fields. The knowledge of nanotoxicology contributes to the understanding of toxicity mechanisms of airborne UFPs in air pollution. This article is part of a Special Issue entitled Air Pollution, edited by Wenjun Ding, Andrew J. Ghio and Weidong Wu.

Knowledge on the interactions between engineered nanomaterials (ENMs) and biological systems is critical both for the assessment of biological effects of ENMs and for the rational design of ENM-based products. However, probing the events that occur at the nano-bio interface remains extremely challenging due to their complex and dynamic nature. So far, the understanding of mechanisms underlying nano-bio interactions has been mainly limited by the lack of proper analytical techniques with sufficient sensitivity, selectivity and resolution for characterization of nano-bio interface events. Moreover, many classic bioanalytical methods are not suitable for direct measurement of nano-bio interface interactions. These have made establishing analytical methodologies for systematic and comprehensive study of nano-bio interface one of the most focused areas in nanobiology. In this review we have discussed some representative developments regarding analytical techniques for nano-bio interface characterization, including the improvements of traditional methods and the emergence of powerful new technologies. These developments have allowed ultrasensitive, real-time analysis of interactions between ENMs and biomolecules, transformations of ENMs in biological environment, and impacts of ENMs on living systems on molecular or cellular level.

X-ray Photoelectron Spectroscopy (XPS) is a useful surface sensitive tool to explore the particulate matter with different particle sizes. In this work, we report the analysis of elemental species in particulate matter with size ranging from 100nm to 10μm during the autumn haze of 2014 in Beijing. The size dependence of element composition and chemical state distribution on the particle surface was investigated. It was found that the number of investigated element species decreased from 8 (at stage 2) to 4 (at stage 10) with the decrease of particle sizes down to 100nm, which is in accordance with the result from Transmission electron microscopy (TEM/EDX) observations. Three chemical states of nitrogen, the amide group (399.9eV), the ammonium group (401.6eV), and the nitrate group (407.2eV), were confirmed according to the different binding energies. Nitrate was the main composition on the coarse particles, while the percentage of amide and ammonium at stage 3 (13.9% and 10.8% respectively) increased on the fine particles at stage 9 (46.8% and 38.8% respectively). The relative ratio of sulfate and ammonium (calculated 1:1) in the fine particles suggests that there is no enough NH4(+) to neutralize the sulfuric acid and the surface of the PM is acidic. The result is useful to investigate the generation processes and the sources of collected particles.

The ceramic composites of Cu-doped La1−xCuxTiO3+δ (x=0.05, 0.15, 0.3, 0.5) were synthesized by conventional solid-state reaction. The complex dielectric properties of the composites were investigated as a function of temperature (77 K≤T≤320 K) and frequency (100 Hz≤f≤1 MHz) separately. In all composites, the dielectric constants increase monotonously and the dielectric loss undulates with temperature. And it is clearly observed that extraordinarily high low-frequency dielectric constant (~104) appear at room temperature in La0.5Cu0.5TiO3+δ, which is ~100 times larger than that of La0.95Cu0.05TiO3+δ. Interestingly, the dielectric constants increase remarkably with the doped Cu contents, meanwhile the dielectric loss for all samples is ideal lower than 1 at room temperature in the measured frequency range. By means of complex impedance analysis, the improvements of dielectric properties are attributed to both bulk contribution and grain boundary effect, in which the bulk polaronic relaxation and the Maxwell–Wagner relaxation due to grain boundary response are heightened remarkably with the high doped Cu contents.

Graphene and modified graphene can provide exceptional lubrication when used as additives. Here, we applied several types of graphene on steel tribo-couples to perform friction tests. The results indicate that the solution concentration and processing method regarding the graphene-containing alcohol solution can significantly affect the lubrication performance. Graphene nanoflakes aggregated on the sliding interfaces and underwent structural transformation under high contact pressure after the alcohol completely evaporated. The wear track and wear scar were then effectively protected by the in situ as-formed tribolayer. In contrast, a tribolayer could not form when the tribo-couples slid in a solution environment, as the graphene adsorbed on the contact area could be removed away by the alcohol.

Graphene functionalized nanotips are expected to possess promising potential for various applications based on the outstanding electrical and mechanical properties of graphene. However, current methods, usually requiring a high growth temperature and identical crystal surface to match graphene lattice, are suitable for graphene formation on a flat surface. It remains a big challenge to grow graphene on a nanosized convex surface and fabricate functionalized nanotips with high quality graphene at the apex. In this work, a novel ultrafast annealing method is developed for growing large area graphene on Ni nanotips within 1-2 s. Few layered or multiple layered graphene is presented on the apex or sidewall of the conical tip surface. Direct experimental evidences support that thus-produced graphene is formed via the direct conversion of nickel carbide at the outer surface under the instantaneous high temperature, which is different from the conventional segregation mechanism. This newly developed ultrafast method provides a new route to produce graphene efficiently and economically, promising for both convex surfaces and flat substrates. Moreover, the graphene functionalized nanotips exhibit a great potential for nanoelectrical measurements and conductive scanning probe microscopy (SPM) applications.

The ceramic composites of TbMnO3, Tb0.95Bi0.05MnO3, Tb0.9Bi0.1MnO3 and Tb0.9Bi0.1Mn0.95Fe0.05O3 were compounded by conventional solid-state reaction. Both dielectric constants (ɛ′) and loss tangent (tanδ) of composites have been measured and studied as a function of the temperature from 80 to 400 K and the frequency from 100 Hz to 1 MHz. Interestingly, doping Bi makes dielectric constant decrease and the dielectric dissipation peaks disappear in the high temperature range. But the dielectric constant becomes larger and the dielectric dissipation peaks appear again in the high temperature range after Fe doping appropriately. Analysis indicates that the perovskite structures gradually vary with the increase of Bi replacing Tb, thus the dielectric properties could be enhanced with the small amount of Mn replacement with Fe. Keywords: Perovskite structure, Bi doped TbMnO3, Conduction progress, Dielectric response

Carbon nanocones (CNCs) are conical and seamless microstructures formed by curved multiple-walled graphene layers. CNCs may be used as a kind of novel and stable atomic force microscopy (AFM) tips because of their unique conical shape and high stability. However, the relatively dull multi-walled apex structure hinders the above practical application. Here, we present an approach to sharpen the CNC tip structure to make the material more appropriate for AFM applications. Simply by oxidization in air under optimized conditions, tapered nanocone tips can be obtained. It is notable that no additional structural defects or amorphous carbon impurities were generated after the oxidation process. The sharpened CNCs are believed to be excellent AFM tips with a superb spatial resolution and high stability. Moreover, based on the step-shaped structures in the sidewalls of the processed CNCs, a possible oxidation mechanism is discussed.

Recently, the heavy haze weather frequently attacked the majority of Chinese cities throughout the country. Research results have shown clear associations between short-term or long-term exposure to ambient fine particles (FPs, PM2.5) and the increased incidence and mortality of cardiovascular or respiratory diseases. However, the ambient ultrafine particles (UFPs, PM0.1) are dominant contributors to particle number in haze weather. Compared with FPs, UFPs could be inhaled and deposited more deeply into the lung, and may carry more toxicants and poses larger interface with biological systems. So, it has been proposed that UFPs are more harmful to human health than bigger ones, and their health effects warrant further comprehensive assessment. In the last decade, nanotoxicology has been developed quickly. By taking advantage of new conception, new knowledge and methodology from nanotoxicology studies, we here discuss comprehensively the UFPs health effects on respiratory and cardiovascular systems. We also try to identify the further research priorities and provide suggestions when studying health effects of ambient UFP in China: (1) systematic study of associations between physicochemical characteristics of ambient UFPs (such as resources, components, structures, sizes, surface, interface, et al.) and health effects, especially associations among chemical conversion, biological behavior, toxicological response and underlying mechanisms; (2) systematic appreciation of small-size-effects, surface effects, interface effects, multi-component synergistic effects and effects of multiple weak interactions for ambient UFPs; (3) systematic assessment of health effects of ambient UFPs on potential susceptible populations (for example, children, the elderly and patients with cardiovascular and pulmonary diseases) and relevant triggering mechanisms; (4) systematic establishment of analytical methods and technologies for health effects studies, especially development of integrated source apportionment methods and on-line analytical methods and technologies for health effects analysis; (5) Nanotoxicology has evolved comparatively systematic and complicated research methodologies, experimental techniques and basic knowledge, which will be of great enlightenment for ambient UFP health effects studies, although ambient UFPs and their structures, components and surface characteristics are easily affected by factors such as resources, seasons and meteorology; (6) Large-scale cohort studies of ambient UFPs (PM0.1) health effects should be conducted at the same time when the cohort studies of ambient FPs (PM2.5) health effects are performed. Fast action will benefit the knowledge pool of ambient UFPs health effects with our specific pollution background, and appropriate measures can be taken to alleviate harms. For that end, the close collaborations among atmospheric researchers, environmental protection department staff working on atmospheric monitoring and health science researchers are of most importance.

Owing to the small diameter, wear resistance, high aspect ratio of their cylindrical structure and outstanding young's modulus, carbon nanotubes are regarded as excellent probes for atomic force microscope (AFM) imaging and various applications. To take the best out of carbon nanotubes’ potentials as AFM probes, we present a facile and reliable method to attach a single carbon nanotube onto an AFM probe covered with conductive Au layer. The method involves the following steps: positioning the AFM probe exactly onto a designated multiple-walled carbon nanotube growing vertically on a conductive substrate, establishing physical contact of the probe apex to the carbon nanotube with an appropriate force, and finally flowing a DC current of typically 100 μA from the AFM probe to the substrate through the carbon nanotube. The current flow results in the fracture and attachment of the carbon nanotube onto the AFM probe. Our method is similar to that reported in previous studies to cut and assemble carbon nanotubes by flowing current under SEM, but by our method we succeed to achieve superior control of protruding length and reproducible attachment angle of the carbon nanotube in one step. Moreover, it is now possible to reliably prepare carbon nanotube probes in-situ during AFM experiments.

The ceramic composites of Tb 1− x Fe x MnO 3 ( x =0.05, 0.1, 0.2, 0.3, 0.4) were synthesized by conventional solid-state reaction. The dielectric constants and loss of composites as a function of temperature (from 77 to 350 K) and frequency (from 0.1 to 200 kHz) were measured. Interestingly, in all composites, Tb 0.95 Fe 0.05 MnO 3 sample not only enjoys the highest dielectric constants (~10 4 ) in the high temperature and low frequency range, but also presents the lowest loss in the high frequency range. Debye-like dielectric dissipation peaks shift to high temperature range with the increase of frequency, which become unobvious in high iron content doping samples. Analysis indicates that the perovskite structures gradually change with the increase of Fe content and the dielectric properties of TbMnO 3 can be improved by adding Fe with appropriate content.

Low-frequency (0.1–200 kHz) dielectric properties of Tb1−xGaxMnO3 and TbGayMn1−yO3 (x, y = 0.05, 0.1, 0.2, 0.3, 0.4) ceramic composites, which were synthesized by conventional solid-state reaction, were investigated in the temperature range from 77 to 350 K. Both dielectric constants and loss tangent (tan δ) increase with increasing temperature and decrease with increasing frequency, respectively. Interestingly, the dielectric constants of Tb1−xGaxMnO3 are as large as that of the parent TbMnO3, while the loss tangent reduces remarkably and less than 1 at high frequencies. These improvements demonstrate that Ga doped TbMnO3 may have potential applications.

Cardiac tissue engineering (CTE) has developed rapidly, but a great challenge remains in finding practical scaffold materials for the construction of engineered cardiac tissues. Carbon nanohorns (CNHs) may be a potential candidate due to their special structure and properties. The purpose of this study was to assess the effect of CNHs on the biological behavior of neonatal rat ventricular myocytes (NRVMs) for CTE applications. CNHs were incorporated into collagen to form growth substrates for NRVMs. Transmission electron microscopy (TEM) observations demonstrated that CNHs exhibited a good affinity to collagen. Moreover, it was found that CNH-embedded substrates enhanced adhesion and proliferation of NRVMs. Immunohistochemical staining, western blot analysis, and intracellular calcium transient measurements indicated that the addition of CNHs significantly increased the expression and maturation of electrical and mechanical proteins (connexin-43 and N-cadherin). Bromodeoxyuridine staining and a Cell Counting Kit-8 assay showed that CNHs have the ability to inhibit the proliferation of cardiac fibroblasts. These findings suggest that CNHs can have a valuable effect on the construction of engineered cardiac tissues and may be a promising scaffold for CTE. Electronic supplementary material The online version of this article (doi:10.1186/s11671-016-1464-z) contains supplementary material, which is available to authorized users.

Carbon nanohorn (CNH) aggregates are spherical with a diameter of ∼80 nm. There are thousands of protruding nanohorns at the periphery of each CNH aggregate. However, the interior structure of CNH aggregates remains a question. In this work, we used focused ion beam (FIB) to cut CNH aggregates followed by electron microscopy observations. It was revealed that the interior consists of disordered single-layered graphene sheets with a lateral size of up to 10 nm and an interlayer distance of approximately 4–5 A. The growth mechanism of CNH aggregates was discussed on the basis of this new finding.

High-rate techniques, such as optical orthogonal frequency division multiplexing (OFDM) and color shift keying (CSK), have been proposed for visible light communication (VLC). To fully exploit their advantages, in this Letter, we design a modulation scheme called rotated polarity modulation (RPM) aided complex CSK (CCSK) for OFDM-based VLC systems and derive its theoretical bit error rate and an optimal scaling factor. Analytical and simulation results show that in comparison to the existing schemes, the new RPM-CCSK-OFDM system offers an improved link performance and data rate under a modest complexity. It can also be applied to VLC systems equipped with different types of LED devices, thus enabling flexible deployments.

It has been reported that single wall carbon nanohorns (SWCNHs) with holes opened by slow air oxidation have few carbonaceous dusts inside nanohorns, which is advantageous for storing materials inside the inner nanospaces of SWCNHs. However, the number of carboxyl groups of air-oxidized SWCNHs is small, which is disadvantageous for chemical functionalization. We show in this report that the double oxidation, namely the slow air-oxidation followed by treatment with hydrogen peroxide at room temperature for 4 days successfully formed the holes in walls of SWCNHs without few carbonaceous dusts and with many carboxyl groups.

Aiming at improving the dispersion state of single wall carbon nanohorns (SWNHs) in highly salted aqueous environment for potential biological applications, we compared the dispersion ability of different PEG-based dispersants in this work. We have found that ceramide-conjugated poly(ethylene glycol) (CPEG) dispersed SWNHs better than phospholipid-conjugated PEG (DPEG) in both water and phosphate buffer saline (PBS), which was evidenced by the measurements of particle sizes and dispersion stability. The large zeta potentials, according to the high surface charges, did not fully explain the high dispersion ability of CPEG for SWNHs. We propose that the more neutral linker group between alkyl and PEG chains in CPEG, in contrast to the charged phosphoethanolamino group in DPEG, resulted in the larger number of CPEG molecules attaching on SWNHs, and those PEG molecules enhanced the dispersion of SWNHs in water and PBS. In addition, for the first time we reported the adverse effect of the amino terminal group of PEG chain on the dispersion ability, compared with the methyl terminal group.

A single wall carbon nanohorn (SWNH) is a new kind of single-graphene tubules with a diameter of 2–5 nm and a length 40–50 nm. In this work, we used oxidized SWNH (SWNHox) to incorporate vancomycin hydrochloride (VCM) for its controlled release by taking advantage of the interactions between VCM and SWNHox. Phospholipid–poly(ethylene glycol) was used to modify the hydrophobic surface of SWNHox to improve its dispersion in aqueous systems. In the release study using this complex, a stable release of VCM was achieved for an extended period.

The atomic cations of Sr and Mo have been observed to add sequentially up to four molecules of C 60 in helium at 0.35 Torr and room temperature in the flow tube of a modified inductively coupled plasma/selected-ion flow tube (ICP/SIFT) tandem mass spectrometer. The available center-of-mass energy in collision-induced dissociation experiments of approximately 1.3 eV failed to remove C 60 from M + (C 60 ) 4 . A structure is proposed for M + (C 60 ) 4 cations in which the bonding involves η 6 interaction of the metal with the C 60 ligands and η 2 -to-η 2 interactions between the C 60 ligands.