论西方美学思想与中国书法的结合

西方美学思想可以用来指导生活中的艺术审美,书法是中国历史长河中的艺术瑰宝,西方美学的思想也可以用来启发中国书法的学习。文章分别从书法的选帖、入帖、墨效、修为、评价等不同角度与西方的一些美学观点结合,分别进行阐述。

Flotation studies on low grade graphite ore from eastern India

A low grade graphite ore from eastern India was beneficiated by flotation to improve its quality. The ore was composed of 87.80%ash and 8.59%fixed carbon. Primary coarse wet grinding （d80：186 μm） followed by rougher flotation in Denver flotation cell using diesel as collector and pine oil as frother yielded a rougher concentrate. Regrinding （d80：144 μm） of this rougher concentrate was opted for further libera-tion of graphite. It was followed by cleaning in laboratory flotation column. This combined process of relatively coarse primary grinding followed by regrinding and cleaning in flotation column resulted in final concentrate of 7.44% yield with 89.65% fixed carbon and 6.00% ash. This approach of two-stage grinding to recover the flake graphite at the coarsest possible grind can help to minimize grinding energy costs. A conceptual flow sheet which is cost effective was developed based on this methodology.

Bio-derived N-doped porous carbon as sulfur hosts for high performance lithium sulfur batteries

Shuttle effect,poor conductivity and large volume expansion are the main factors that hinder the practical application of sulfur cathodes.Currently,rational structure designing of carbon-based sulfur hosts is the most effective strategy to address the above issues.However,the preparation process of carbon-based sulfur hosts is usually complex and costly.Therefore,it is necessary to develop an efficient and cost-effective method to fabricate carbon hosts for high-performance sulfur cathodes.Herein,we reported the fabrication of a bio-derived nitrogen doped porous carbon materials(BNPC)via a molten-salt method for high performance sulfur cathodes.The long-range-ordered honeycomb structure of BNPC is favorable for the trapping of polysulfide(PS)species and accommodates the volumetric variation of sulfur during cycling,while the high graphitization degree of BNPC favors the redox kinetics of sulfur cathodes.Moreover,the nitrogen doping content not only enhances the electrical conductivity of BNPC,but also provides ample anchoring sites for the immobilization of PS,which plays a key role in suppressing the shuttle effect.As a result,the S@BNPC cathode exhibits a high initial specific capacity of 1189.4 mA·h/g at 0.2C.After 300 cycles,S@BNPC still maintains a capacity of 703.2 mA·h/g which corresponds to a fading rate of 0.13%per cycle after the second cycle.This work offers vast opportunities for the large-scale application of high performance carbon-based sulfur hosts.

Impact of Channel Length and Width for Charge Transportation of Graphene Field Effect Transistor

The effect of channel length and width on the large and small-signal parameters of the graphene field effect transistor have been explored using an analytical approach.In the case of faster saturation as well as extremely high transit frequency,the graphene field effect transistor shows outstanding performance.From the transfer curve,it is observed that there is a positive shift of Dirac point from the voltage of 0.15 V to 0.35 V because of reducing channel length from 440 nm to 20 nm and this curve depicts that graphene shows ambipolar behavior.Besides,it is found that because of widening channel the drain current increases and the maximum current is found approximately 2.4 mA and 6 mA for channel width 2μm and 5μm respectively.Furthermore,an approximate symmetrical capacitance-voltage(C-V)characteristic of the graphene field effect transistor is obtained and the capacitance reduces when the channel length decreases but the capacitance can be increased by raising the channel width.In addition,a high transconductance,that demands high-speed radio frequency(RF)applications,of 6.4 mS at channel length 20 nm and 4.45 mS at channel width 5μm along with a high transit frequency of 3.95 THz have been found that demands high-speed radio frequency applications.

GO-induced effective interconnection layer for all solution-processed tandem quantum dot light-emitting diodes

Compared to conventional quantum dot light-emitting diodes,tandem quantum dot light-emitting diodes(TQLEDs)possess higher device efficiency and more applications in the field of flat panel display and solid-state lighting in the future.The TQLED is a multilayer structure device which connects two or more light-emitting units by using an interconnection layer(ICL),which plays an extremely important role in the TQLED.Therefore,realizing an effective ICL is the key to obtain high-efficiency TQLEDs.In this work,the p-type materials polys(3,4-ethylenedioxythiophene),poly(styrenesulfonate)(PEDOT:PSS)and the n-type material zinc magnesium oxide(ZnMgO),were used,and an effective hybrid ICL,the PEDOT:PSS-GO/ZnMgO,was obtained by doping graphene oxide(GO)into PEDOT:PSS.The effect of GO additive on the ICL was systematically investigated.It exhibits that the GO additive brought the fine charge carrier generation and injection capacity simultaneously.Thus,the all solutionprocessed red TQLEDs were prepared and characterized for the first time.The maximum luminance of 40877 cd/m^(2) and the highest current efficiency of 19.6 cd/A were achieved,respectively,showing a 21%growth and a 51%increase when compared with those of the reference device without GO.The encouraging results suggest that our investigation paves the way for efficient all solution-processed TQLEDs.

The Use of Melengestrol Acetate as a Strategy to Improve Production Efficiency of Sheep in Rural Areas in Mexico

The aim of this study was to evaluate the use of melengestrol acetate （MGA） as a strategy to improve the production efficiency in ewes of rural areas in Mexico. Twenty ewes of breeds （Dorper and Dorper with Pelibuey） non-pregnant and with ovarica activity were used. The treatment consisted of the administration of 0.22 mg MGA/ewe/d for 17 d. The MGA efficiency was measured once the treatment finalized, and the producer was responsible for the registration of the estrus presentation and prolificacy rate. 95% of the sheep presented estrus in a period of 14 d after stopping treatment. The prolificacy percentage was of 1.2 lambs born by ewe during a period of six months （including treatment and period of gestation）. In conclusion, the use of MGA represents an alternative to improve the efficiency of sheep production in rural areas in Mexico, since it can increase the number of lambs by 30% in a period of 12 months.

Negative inductive effect enhances charge transfer driving in sulfonic acid functionalized graphitic carbon nitride with efficient visible-light photocatalytic performance

Efficient photogenerated carrier migration/separation plays a critical role in increasing the photocatalytic performance of g-C_(3)N_(4).Herein,sulfonic acid group-functionalized g-C_(3)N_(4)(SACN)was synthesized and then synchronously strengthened by a facile-solid-state thermal reaction of g-C_(3)N_(4)and sulfamic acid.As a solid strong acid,sulfamic acid can be used to achieve acid etching on the surface of g-C_(3)N_(4)with the assistance of thermal treatment,leading to an enlarged specific surface area and increased surface catalytic reaction sites.More importantly,our experiments and density functional theory calculations indicate that the driving force generated by the negative inductive effect of sulfonic acid groups significantly improves the charge transfer dynamics and effectively inhibits their recombination.Moreover,the negative inductive effect can induce charge redistribution,which reduces the conduction band potential of g-C_(3)N_(4)to enhance the reduction ability of photo-induced electrons.As a result,the SACN-400 sample showed excellent photocatalytic performance in H2 generation with an apparent quantum efficiency of 11.03%at 420±15 nm,as well as an efficient photodegradation rate for organic pollutants.

Field experiments to improve the efficacy of gargoor (fish trap) fishery in Kuwait's waters

Fish traps were investigated to understand the effects of season, bait type, trap size, and trap soak time on catch rates, catch composition, and trap loss rates from March 2004 to September 2005, to improve the performance and management of Kuwait＇s gargoor （cage style fish trap） fishery, which used to be the nation＇s most important one in terms of value and landings volume. Catch rates were the highest in April/May （5 8 kg/trap haul） and again in December （7 kg/trap haul）. Bait type and trap size also affected catch rates and species composition. Of the seven baits tested, the best catch rates, 〉5 kg/trap haul, occurred with cuttlefish （Sepia pharaonis）, but wolf-herring （Chiroeentrus dorab） and mullet （Liza klunzingeri） also produced good results （4-5 kg/trap haul）. Within the five tested sizes, the two largest-sized traps captured more fish and larger size fish. Analysis of variance （ANOVA） showed significant differences of catch rate among traps with different baits as well as among traps of different sizes. Duncan test further revealed these differences between two specific baits and sizes. Cluster Analysis of species composition showed more differences among different baits than among different trap sizes. Longer soak times did not result in larger catch rates, but increased trap loss. About 10-day soak time resulted in trap loss 7%, while 40-day soak time could result in a loss of around 20%. Consequently, it is recommended that the gargoor be checked every 10 or fewer days. The average overall catch rate during the study period was lower than that of 1980s （4.5 vs. 5.8 kg/trap haul）, indicating a possible decline offish abundance in Kuwait＇s waters. It is recommended that the number of gargoor fishing boats and gargoors from each boat should be limited to allow stock rehabilitation.

Qualitative Perspective of Audit Materiality： Empirical Evidence in Mexico and Colombia

Our contribution analyzes the process of convergence with the International Standards of Audit （ISAs）, particularly those that regulate the concept of materiality in Mexico and Colombia. Between other results, across a survey, it is demonstrated why the effective use of the factors that emerge of his qualitative slope can favor the quality of the financial information that publish the audited companies, the usefulness and the comprehensibility of the report of opinion. In general, the reliability, transparency, and relevancy of the financial statements will meet potentially favored with the strict application of these major and better normative instruments.

Public and Private Investment in the Port Sector in Mexico, 2000-2010： A Study Through Data Envelopment Analysis

Knowing the level of efficiency of investment applied in ports of Mexico is relevant information for the design of port policies that contribute to its development and thus to greater freight movement. The objective of this paper is to analyze the technical efficiency obtained from International Mexican Ports, through the use of the technique of Data Envelopment Analysis （DEA）. It uses data regarding public and private investment in ports applied during the period 2000-2010 and its influence on the number of Twenty-foot Equivalent Unit （TEU）. Because it has been applied the DEA-CCR （the linear programming model） model input oriented, thus not only the efficiency is calculated in ports, but benchmarking is also obtained to determine the efficient ports that serve as reference to those who were found to be inefficient. The results obtained showed that Manzanillo and Progreso were the most efficient ports. On the other hand, the ports that were not efficient for any of the years reviewed were Mazatlan and Lazaro Cardenas. Generally, public investment has been increasing over the period, and public policies are not designed to allow the ports to have an international projection.

Fabrication and characterization of graphene derived from SiC

Using novel ideas for the fabrication of epitaxial graphene （EG） on SiC, two forms of graphene termed as vertical aligned gra- phene sheets （VAGS） and graphene covered SiC powder （GCSP） were derived, respectively, from SiC slices and SiC powder, aimed for applications in energy storage and photocatalysis. Herein, the fabrication procedures, morphology characteristics, some intrinsic physical properties and performances for applications in field effect transistor （FET） and cold cathode field emission source are revealed and analyzed based on the graphene materials. The EG on a 2-inch SiC （0001） showed an average sheet resistance about 720 D,/~5 with a non-uniformity 7.2%. The FETs fabricated on the EG possessed a cutoff frequency 80 GHz. Based on the VAGS derived from a completely carbonized SiC slice, a magnetic phase diagram of graphene with irregu- lar zigzag edges is also reported.

Spin valve effect of NiFe/graphene/NiFe junctions

When spins are injected through graphene layers from a transition metal ferromagnet, high spin polarization can be achieved. When detected by another ferromagnet, the spin-polarized current makes high- and low-resistance states in a ferromagnet/graphene/ferromagnet junction. Here, we report manifest spin valve effects from room temperature to 10 K in junctions comprising NiFe electrodes and an interlayer made of double-layer or single-layer graphene grown by chemical vapor deposition. We have found that the spin valve effect is stronger with double-layer graphene than with single-layer graphene. The ratio of relative magnetoresistance increases from 0.09% at room temperature to 0.14% at 10 K for single-layer graphene and from 0.27% at room temperature to 0.48% at 10 K for double-layer graphene. The spin valve effect is perceived to retain the spin-polarized transport in the vertical direction and the hysteretic nature of magnetoresistance provides the basic functionality of a memory device. We have also found that the junction resistance decreases monotonically as temperature is lowered and the current-voltage characteristics show linear behaviour. These results revealed that a graphene interlayer works not as a tunnel barrier but rather as a conducting thin film between two NiFe electrodes.

Scalable arrays of chemical vapor sensors based on DNA-decorated graphene

Arrays of chemical vapor sensors based on graphene field effect transistors functionalized with single-stranded DNA have been demonstrated. Standard photolithographic processing was adapted for use on large-area graphene by including a metal protection layer, which protected the graphene from contamination and enabled fabrication of high quality field-effect transistors （GFETs）. Processed graphene devices had hole mobilities of 1,640 ± 250 cm2.V-1.s-1 and Dirac voltages of 15 ± 10 V under ambient conditions. Atomic force microscopy was used to verify that the graphene surface remained uncontaminated and therefore suitable for controlled chemical functionalization. Single-stranded DNA was chosen as the functionalization layer due to its affinity to a wide range of target molecules and π-π stacking interaction with graphene, which led to minimal degradation of device characteristics. The resulting sensor arrays showed analyte- and DNA sequence-dependent responses down to parts-per-billion concentrations. DNA/GFET sensors were able to differentiate among chemically similar analytes, including a series of carboxylic acids, and structural isomers of carboxylic acids and pinene. Evidence for the important role of electrostatic chemical gating was provided by the observation of understandable differences in the sensor response to two compounds that differed only by the replacement of a （deprotonating） hydroxyl group by a neutral methyl group. Finally, target analytes were detected without loss of sensitivity in a large background of a chemically similar, volatile compound. These results motivate further development of the DNA/graphene sensor family for use in an electronic olfaction system.

Oxide-on-graphene field effect bio-ready sensors

Electrical detection schemes using nanoscale devices offer fast and label-free alternatives to biosensing techniques based on chemical and optical interactions. Here we report on the design, fabrication, and operation of oxide-on-graphene ion-sensitive field effect sensor arrays using large-area graphene sheets synthesized by chemical vapor deposition. In this scheme, HfO2 and SiO2 thin films are deposited atop the graphene sheet and play the dual role of the sensing interface, as well as the passivation layer protecting the channel and electrodes underneath from direct contact with the electrolyte. We further demonstrate the functionalization of the SiO2 surface with 3-aminopropyltrimethoxysilane （APTMS）. The oxide-on-graphene sensors operate in solution with high stability and a high average mobility of 5,000 cm2/（V＇s）. As a proof of principle, we demonstrate pH sensing using the bare or the APTMS-functionalized SiO2 as the sensing surface. The measured sensitivities, 46 mV/pH and 43 mV/pH, respectively, agree well with existing studies. We further show that by applying the solution gate voltage in pulse, the hysteresis in the transfer curve of the graphene transducer can be eliminated, greatly improving the ionic potential resolution of the sensor. These experiments demonstrate the potential of oxide-on-graphene ion-sensitive field effect sensors in on-chip, label-free and real-time biosensing applications.

A new type of covalent-functional graphene donor-acceptor hybrid and its improved photoelectrochemical performance

Graphene has lots of applications, such as field-effect transistors, solar cells and transparent electrodes. In this work, we developed a new donor-acceptor graphene hybrid by covalently bonding a donor phenanthrene-9-carboxaldehyde (PCA) onto the acceptor graphene (PCA-graphene) via 1,3-dipolar cycloaddition azomethine ylides. The resulting PCA-graphene is soluble in N,N-dimethyformamide (DMF). The optoelectronic device (photoanode) fabricated by spin-coating DMF solution of the hybrids exhibits an enhanced photocurrent under visible irradiation.

Direct synthesis of highly conductive poly（3,4- ethylenedioxythiophene）：poly（4-styrenesulfonate） （PEDOT：PSS）/graphene composites and their applications in energy harvesting systems

We report for the first time highly conductive poly（3,4-ethylenedioxythiophene）： poly（4-styrenesulfonate） （PEDOT：PSS）/graphene composites fabricated by in situ polymerization and their applications in a thermoelectric device and a platinum （Pt）-free dye-sensitized solar cell （DSSC） as energy harvesting systems. Graphene was dispersed in a solution of poly（4-styrenesulfonate） （PSS） and polymerization was directly carried out by addition of 3,4-ethylenedioxythiophene （EDOT） monomer to the dispersion. The content of the graphene was varied and optimized to give the highest electrical conductivity. The composite solution was ready to use without any reduction process because reduced graphene oxide was used. The fabricated film had a conductivity of 637 S.cm-1, corresponding to an enhancement of 41%, after the introduction of 3 wt.% graphene without any further complicated reduction processes of graphene being required. The highly conductive composite films were employed in an organic thermoelectric device, and the device showed a power factor of 45.7 μW·m^-1K^-2 which is 93% higher than a device based on pristine PEDOT：PSS. In addition, the highly conductive composite films were used in Pt-free DSSCs, showing an energy conversion efficiency of 5.4%, which is 21% higher than that of a DSSC based on PEDOT：PSS.

Anti-photocorrosive photoanode with RGO/PdS as hole extraction layer

Photoelectrochemical(PEC)hydrogen production is of great interest as an ideal avenue towards clean and renewable energy.However,the instability and low energy conversion efficiency of photoanodes hinder their practical applications.Here we address these issues by introducing a hole extraction layer(HEL)which could rapidly transfer and consume photogenerated holes.The HEL is constructed by reduced graphene oxide(RGO)and other cocatalysts that enable rapid transfer and subsequent consumption of holes,respectively.Specifically,we showcase a high-stability photoanode composed of CdSeTe nanowires(CST NWs)and RGO/PdS nanoparticles(PdS NPs)based HEL.The photoanode achieves excellent photocorrosion resistance,which allows stable hydrogen evolution for>2 h at 0.5 VRHE.

Is quantum capacitance in graphene a potential hurdle for device scaling？

Transistor size is constantly being reduced to improve performance as well as power consumption. For the channel length to be reduced, the corresponding gate dielectric thickness should also be reduced. Unfortunately, graphene devices are more complicated due to an extra capacitance called quantum capacitance （CQ） which limits the effective gate dielectric reduction. In this work, we analyzed the effect of CQ on device-scaling issues by extracting it from scaling of the channel length of devices. In contrast to previous reports for metal-insulator- metal structures, a practical device structure was used in conjunction with direct radio-frequency field-effect transistor measurements to describe the graphene channels. In order to precisely extract device parameters, we reassessed the equivalent circuit, and concluded that the on-state model should in fact be used. By careful consideration of the underlap region, our device modeling was shown to be in good agreement with the experimental data. CQ contributions to equivalent oxide thickness were analyzed in detail for varying impurity concentrations in graphene. Finally, we were able to demonstrate that despite contributions from CQ, graphene＇s high mobility and low-voltage operation allows for ~raphene channels suitable for next generation transistors.

Reduced graphene oxide with a highly restored π-conjugated structure for inkjet printing and its use in all-carbon transistors

An inkjet-printed graphene film is of great importance for next-generation flexible, low cost and high performance electronic devices. However, due to the limitation of the inkjet printing process, the electrical conductivity of inkjet-printed graphene films is limited to N10 S＇cm-1, and achieving a high conductivity of the printed graphene films remains a big challenge. Here, we develop a ＂weak oxidation- vigorous exfoliation＂ strategy to tailor graphene oxide （GO） for meeting all the requirements of highly conductive inkjet-printed graphene films, including a more intact carbon plane and suitable size. The -conjugated structure of the resulting graphene has been restored to a high degree, and its printed films show an ultrahigh conductivity of -420 S-cm-I, which is tens of times higher than previously reported results, suggesting that, aside from developing a highly efficient reduction method, tuning the GO structure could be an alternative way to produce high quality graphene sheets. Using inkjet-printed graphene patterns as source/drain/gate electrodes, and semiconducting single-walled carbon nanotubes （SWCNTs） as channels, we fabricated an all-carbon field effect transistor which shows excellent performance （an on/off ratio of -104 and a mobility of -8 cm2＂V-l＇s-1） compared to previously reported CNT-based transistors, promising the use of nanocarbon materials, graphene and SWCNTs in printed electronics, especially where high performance and flexibility are needed.

Graphene-templated synthesis of sandwich-like porous carbon nanosheets for efficient oxygen reduction reaction in both alkaline and acidic media

Developing low-cost, high-performance elec- trocatalysts for the oxygen reduction reaction （ORR） is crucial for implementation of fuel cells and metal-air batteries into practical applications. Graphene-based catalysts have been extensively investigated for ORR in alkaline electrolytes. However, their performance in acidic electrolytes still requires further improvement compared to the Pt/C catalyst. Here we report a self-templating approach to prepare graphene-based sandwich-like porous carbon nanosheets for efficient ORR in both alkaline and acidic electrolytes. Graphene oxides were first used to adsorb m-phenylenediamine molecules which can form a nitrogen-rich polymer network after oxidative poly- merization. Then iron （Fe） salt was introduced into the polymer network and transformed into ORR active Fe-N-C sites along with Fe, FeS, and FEN0.05 nanopartides after pyr- olysis, generating ORR active sandwich-like carbon na- nosheets. Due to the presence of multiple ORR active sites. The as-obtained catalyst exhibited prominent ORR activity with a half-wave potential -30 mV more positive than Pt/C in 0.1 mol L-1 KOH, while the half-wave potential of the catalyst was only -40 mV lower than that of commercial Pt/C in 0.1 mol L-1 HClO4. The unique planar sandwich-like structure could expose abundant active sites for ORR. Meanwhile, the graphene layer and porous structure could simultaneously enhance electrical conductivity and facilitate mass transport. The prominent electrocatalytic activity and durability in both alkaline and acidic electrolytes indicate that these carbon na- nosheets hold great potential as alternatives to precious metal- based catalysts, as demonstrated in zinc-air batteries and proton exchange membrane fuel cells.