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Recent research on supercapacitors (SCs) has been attractive due to the potential application in a variety of fields related to energy storage. Electrode materials play a very important role for the performance of SCs and various metal nanoparticles are involved in the SC electrodes. In this paper, the roles of metal nanoparticles for SCs are reviewed and discussed. They can serve as a dopant to modify the surface of electrode materials, or be embedded in a composite to effectively reduce the resistance and lead to an enhanced specific capacitance. Some metal nanoparticles can be also employed as electrode materials directly, but easily being oxidized. Metallic nanoparticles can even act as current collectors, especially for these noble metals with excellent stability and high conductivity. Nanoporous metals prepared by dealloying and electrochemical method can be used as both pseudocapacitive materials and current collector of SCs. Some important experimental data on this issue are summarized. A brief discussion on the future directions, challenges and opportunities in this topic is also provided. [ABSTRACT FROM AUTHOR]

Molecular assembly is the process of organizing individual molecules into larger structures and complex systems. The self-assembly approach is predominantly utilized in creating artificial molecular assemblies, and was believed to be the primary mode of molecular assembly in living organisms as well. However, it has been shown that the assembly of many biological complexes is "catalysed" by other molecules, rather than relying solely on self-assembly. In this review, we summarize these catalysed-assembly (catassembly) phenomena in living organisms and systematically analyse their mechanisms. We then expand on these phenomena and discuss related concepts, including catalysed-disassembly and catalysed-reassembly. Catassembly proves to be an efficient and highly selective strategy for synergistically controlling and manipulating various noncovalent interactions, especially in hierarchical molecular assemblies. Overreliance on self-assembly may, to some extent, hinder the advancement of artificial molecular assembly with powerful features. Furthermore, inspired by the biological catassembly phenomena, we propose guidelines for designing artificial catassembly systems and developing characterization and theoretical methods, and review pioneering works along this new direction. Overall, this approach may broaden and deepen our understanding of molecular assembly, enabling the construction and control of intelligent assembly systems with advanced functionality. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF)-derived pure ZnO and Cu-doped ZnO nanocages were fabricated by calcining a zeolitic imidazole framework (ZIF-8) and Cu-doped ZIF-8. The morphology and crystal structure of the samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). It was found that Cu doping did not change the crystal structures and morphologies of MOF-derived ZnO nanocages. The H2S-sensing properties of the sensors based on ZnO and Cu-doped ZnO nanocages were investigated. The results indicated that the H2S-sensing properties of MOF-derived ZnO nanocages were effectively improved by Cu doping, and the optimal doping content was 3 at%. Moreover, 3 at% Cu-doped ZnO nanocages showed the highest response of 4733 for 5 ppm H2S at 200 °C, and the detection limit could be as low as 20 ppb. The gas-sensing mechanism was also discussed. [ABSTRACT FROM AUTHOR]

Knee osteoarthritis (KOA) is a prevalent and disabling clinical condition affecting joint structures worldwide. The Yiqi Yangxue formula (YQYXF) is frequently prescribed in clinical settings for the treatment of KOA. Existing research has primarily focused on alterations in drug metabolism, with limited investigation into the epigenetic effects of YQYXF, particularly in relation to non-coding RNA. Exploring the effects of YQYXF on critical factors of long chain non-coding RNA UFC1/miR-34a/matrix metalloproteinase-13 (MMP-13) axis and their interrelationships. UHPLC-QE-MS technology was used to identify the YQYXF ingredients in rat serum. KEGG and GO analysis were performed on the targets of blood components acting on KOA using a database. Simultaneously, a protein interaction network was constructed using target proteins and metabolites to identify the core components and key pathways of YQYXF. The KOA rat model was established using an improved Hulth method. SPF SD rats were randomly divided into normal group, sham surgery group, model group, celecoxib capsules group (18 mg/kg), YQYXF low, medium and high dose groups (4.6 g/kg, 9.2 g/kg, 18.4 g/kg). Observe the synovial and cartilage tissues of rats using pathological methods. RT-PCR was used to detect the levels of UFC1, miR-34a, and MMP-13 in cartilage. Immunohistochemistry was used to detect the levels of MMP-13 and ADAMTS-5 in cartilage. ELISA method was used to detect the levels of MMP-13 and ADAMTS-5 in serum. In addition, we further validated the regulation of crucial factor expression levels of UFC1/miR-34a/MMP-13 axis in rat chondrocytes and degenerative chondrocytes of KOA patients by YQYXF, providing a basis for its treatment of KOA. The compounds that YQYXF enters the bloodstream mainly contain flavonoids and phenylpropanoid compounds. The core components that act on OA include quercetin, fisetin, and demethylweldelolactone. The main target pathways are the IL-17 signaling pathway, lipid and atherosclerosis, cellular sensitivity, inflammatory mediator regulation of TRP channels, TNF signaling pathway, relaxin signaling pathway and C-type lectin receptor signaling pathway. YQYXF inhibited the expression of miR-34a and MMP-13 mRNA, and reduced the protein levels of MMP-13 and ADAMTS-5. In vitro studies have confirmed that 20% YQYXF serum promoted UFC1 and reduce miR-34a levels. In addition, miR-34a in sh-UFC1+10% YQYXF serum and sh-UFC1+20% YQYXF serum groups significantly decreased compared to the sh-UFC1 group. The anti-KOA cartilage degeneration effect of YQYXF might be related to inhibiting cell apoptosis and promoting cell proliferation, which regulated the lncRNA-UFC1/miR-34a/MMP-13 axis. [Display omitted] • The compounds that YQYXF enters the bloodstream mainly contain flavonoids and phenylpropanoid compounds. • The core components that act on OA include quercetin, fisetin, and demethylweldelolactone. • LncRNA-UFC1/miR-34a/MMP-13 axis regulates KOA cartilage injury. • YQYXF alleviates KOA through lncRNA-UFC1/miR-34a/MMP-13 axis. [ABSTRACT FROM AUTHOR]

Nuclear spin hyperpolarization derived from parahydrogen is a technique for enhancing nuclear magnetic resonance (NMR) sensitivity. The key to hyperpolarization experiments is to achieve rapid transfer and detection to minimize relaxation losses, while also avoiding bubbles or turbulence to guarantee high spectral resolution. In this article, we describe an experimental approach for the interleaved joint modulation of parahydrogen-induced polarization and NMR. We provide schematic diagrams of parahydrogen-based polarizer with in situ high-pressure detection capability and low-field polarization transfer. This approach can help to control the experimental process and acquire experimental information, one example of which is the attainment of the highest hyperpolarization signal intensity at 3.6 s after closing the valve. The polarizer demonstrates in situ detection capability, allowing sample to be restabilized within 0.3 ± 0.1 s and high-resolution NMR sampling under a pressure of 3 bars. Moreover, it can transfer polarized samples from the polarization transfer field to the detection region of NMR within 1 ± 0.3 s for completing signal amplification by reversible exchange experiments. [ABSTRACT FROM AUTHOR]

SnO2/ZnO@ZIF‐8 core‐shell nanofibers were synthesized by electrospinning and hydrothermal etching ZnO component of SnO2/ZnO nanofibers. It is found that the ZIF‐8 coated SnO2/ZnO nanostructures are obtained, and the ZIF‐8 coating can obviously increase the specific surface area of nanofibers. H2S sensing properties of the sensors based on composite nanofibers were investigated. The results show that SnO2/ZnO@ZIF‐8 core‐shell nanostructures can not only improve the response to H2S, but also effectively reduce the interference of ambient humidity on semiconductor gas sensors. The response of the optimal sample to 5 ppm H2S can reach 202.3, which is about 19 times higher than that of pure SnO2 nanofibers. Compared with the response at the ambient humidity of 55 %RH, the response at the ambient humidity of 90 %RH can still maintain 84.7 %. Good selectivity and stability are also observed in our investigations. [ABSTRACT FROM AUTHOR]

We study the optimal pricing problem for a tandem queueing system with an arbitrary number of stations, finite buffers, and blocking. The problem is formulated using a Markov decision process model with the objective to maximize the long-run expected time-average revenue or gain of the service provider. Our interest lies in comparing the performances of static and dynamic pricing policies in maximizing the gain. We show that the optimal static pricing policies perform as well as the optimal dynamic pricing policies when the buffer size at station 1 becomes large and the arrival rate is either small or large. More importantly, we propose two specific static pricing policies for systems with small and large arrival rates, respectively, and show that each proposed policy produces a gain converging to the optimal gain with an approximately exponential rate as the buffer size before station 1 becomes large. We learn from numerical results that the proposed static policies perform as well as optimal dynamic policies even for a moderate-sized buffer at station 1. We also learn that there exist cases where optimal static pricing policies are, however, neither optimal nor near-optimal. [ABSTRACT FROM AUTHOR]

The electrical power consumption, which is approximately equal to the thermal budget, accounts for the majority of the total cost to synthesize diamond films by the hot filament chemical vapor deposition (HFCVD) apparatus. In this study, two strategies, visualizing as certain additional parts in the apparatus, are proposed for reducing the thermal budget and synthesis cost. Detailed effects are proven by the finite volume method (FVM) simulation, temperature measurement and deposition experiments, demonstrating that the reduction of thermal conductivity of the worktable (by changing the worktable material) and the insertion of the circular ring copper shielding will significantly contribute to the reduction of the heat dissipation and substrate temperature rise. Influences of major filament parameters on substrate temperature values and distributions are then clarified, suggesting that in order to control the substrate temperatures in a similar and reasonable range in the modified apparatus, the best choice is to synchronously reduce the filament diameter and the electrical power, while retaining the filament temperature still in a high level (around 2200 °C). Finally, the energy saving ratios are as high as 28.4% (experimental apparatus) and 27.4% (commercial apparatus), and the substrate temperature distributions can also be improved, guaranteeing the uniformity of as-deposited diamond films on mass substrates. [Display omitted] • Two strategies are proposed for reducing the thermal budget and synthesis coast of HFCVD diamonds. • Thermal conduction from worktable to cooling water is reduced by changing worktable material. • Thermal radiation from filaments to water-cooled wall is reduced by inserting copper shielding. • Filament diameter and electrical power should be both reduced to obtain appropriate temperatures. • Energy saving ratios are as high as 28.4% (experimental apparatus) and 27.4% (commercial apparatus). [ABSTRACT FROM AUTHOR]

Freestanding diamond films are widely applied, but available fabrication techniques present obvious flaws. A new route to fabricate high-quality double-side-polished freestanding diamond film is proposed in this study. Typical MCD (Micro-crystalline diamond) or NCD (Nano-crystalline diamond) film is firstly deposited on pretreated SiC substrate by HFCVD technique. As-grown surfaces are smoothened by mechanical polishing. Diamond films are then separated from substrates by laser cutting. Finally, bottom surfaces, which are known as nucleated surfaces, are also polished. Compared with the Mo substrate used in the conventional route based on the natural peeling off of the diamond film, the thermal deformation and residual stress of the diamond film on the SiC substrate are smaller, mainly due to the reduced difference between thermal expansion coefficients of the diamond film and substrate. This is beneficial for avoiding the fracture of freestanding films in the cooling stage, and also beneficial for the subsequent polishing. Consequently, the interruptible repeated growth strategy with constant growth rates (1.0–1.2 μm/h for MCD and 1.3–1.5 μm/h for NCD) is feasible, and the long-duration operation of HFCVD device is dispensable. Compared with the Si substrate used in the route based on the Si etching, the SiC substrate is much more reusable in the present route. • A new route is proposed for preparing free-standing diamond film is proposed. • Selection of SiC substrate is beneficial for reducing the thermal residual stress. • The interruptible repeated growth strategy is feasible. • Separation of diamond film from substrate is accomplished by laser cutting. • SiC substrate can be recycled, which is environmentally-friendly and resource-conserving. [ABSTRACT FROM AUTHOR]

We consider optimal pricing for a two-station tandem queueing system with finite buffers, communication blocking, and price-sensitive customers whose arrivals form a homogeneous Poisson process. The service provider quotes prices to incoming customers using either a static or dynamic pricing scheme. There may also be a holding cost for each customer in the system. The objective is to maximize either the discounted profit over an infinite planning horizon or the long-run average profit of the provider. We show that there exists an optimal dynamic policy that exhibits a monotone structure, in which the quoted price is non-decreasing in the queue length at either station and is non-increasing if a customer moves from station 1 to 2, for both the discounted and long-run average problems under certain conditions on the holding costs. We then focus on the long-run average problem and show that the optimal static policy performs as well as the optimal dynamic policy when the buffer size at station 1 becomes large, there are no holding costs, and the arrival rate is either small or large. We learn from numerical results that for systems with small arrival rates and no holding cost, the optimal static policy produces a gain quite close to the optimal gain even when the buffer at station 1 is small. On the other hand, for systems with arrival rates that are not small, there are cases where the optimal dynamic policy performs much better than the optimal static policy. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Monolayer diamond grinding tools are commonly made by electroplating or brazing. However, electroplated tools involve weak grain/matrix adhesion due to a lack of chemical bonds, and brazed diamonds often suffer thermal damage resulting from the high-temperature brazing process. This paper reports a new method to fabricate monolayer diamond grinding tools by chemical vapor deposition (CVD) technique. First, diamond powders at the range of 7–180 μm are chosen as seeds of the abrasive grains. The seeds are randomly distributed on SiC substrates by spraying the suspension containing the seeds toward the substrates in a spin coater machine, or orderly positioned on the substrates by a patterned mask. Then CVD diamond growth is conducted on both the substrates and the seeds simultaneously. As-grown diamond films on the substrates are regarded as bonding layers of the grinding tools, and the original seeds with irregular and crushed morphologies can grow into blocky cube-octahedral grains with smooth surfaces, which are supposed to have enhanced mechanical strength. Raman spectra demonstrate that as-grown diamonds on both the substrates and the seeds are of high quality and low levels of graphitization. Besides, relatively low residual stresses are detected in the diamond grains, because both the bonding layers and the grains are made of diamond. Grinding tests are conducted using as-fabricated CVD diamond grinding tools and electroplated/brazed diamond grinding tools as comparisons. The results suggest that the CVD diamond grinding tools possess the best wear resistance in terms of the fracture of the diamond grains. This is attributed to the epitaxial grain structure that restrains the crack propagations. In addition, the wear of the CVD diamond grains can generate tiny pyramidal crystalline tips and sharp edges, indicating the unique shelf-sharpness during the grinding. [ABSTRACT FROM AUTHOR]

A fractal tiling or f -tiling is a tiling which possesses self-similarity and the boundary of which is a fractal. By substitution rule of tilings, this short paper presents a very simple strategy to create a great number of f -tilings. The substitution tiling Equithirds is demonstrated to show how to achieve it in detail. The method can be generalized to every tiling that can be constructed by substitution rule. [ABSTRACT FROM AUTHOR]

Abstract The frictional resistance and hole quality when drilling CFRP laminates are associated with tribological behaviors of drill materials. In the present study, tribological tests are conducted on various diamond coated WC-Co balls sliding against T800/X850 CFRP laminates with [-45/90/45/0]s lay-up, under specific conditions similar to the drilling process. It is firstly found that the coefficient of friction (COF) varies with the sliding direction. The boron-doped micro-crystalline and nano-crystalline composite diamond (BDMC-NCCD) film synthesized by optimized growth durations (9 h for BDMCD and 2.5 h for NCD) presents relatively low COF and wear rate (0.193 and 0.97 × 10−8 mm3/N m, when the sliding velocity and normal load are respectively 1.5 m/s and 5.0 N), as well as high critical load for the film peeling (35 N), owing to the nano-sized diamond grains and low surface roughness (R a ~125.09 nm measured by the confocal microscopy) of the surface NCD layer, and high hardness and favorable adhesion of the underlying BDMCD layer. Besides, influences of the sliding velocity and normal load are clarified, indicating that the COF increases with the load, but decreases with increasing the velocity, while the wear rate increases with either the load or velocity. Highlights • Tribological test condition is defined according to drilling test. • Five typical types of diamond films are tested sliding against CFRP sections. • Coefficient of friction is dependent on sliding direction. • BDMC-NCCD film synthesized by optimized durations perform the best. • Optimized growth durations are 9 h for BDMCD and 2.5 h for NCD. [ABSTRACT FROM AUTHOR]

Abstract In this work, a comparative study of diamond films consisting of alternate microcrystalline (MCD) and nanocrystalline diamond (NCD) layers is conducted. Diamond films including monolayer, bilayer and multilayer diamond films are coated on cemented tungsten carbide (WC-Co) substrates by adopting a bias-enhanced hot filament chemical vapor deposition (HFCVD) technique. Tribological properties of the diamond films are evaluated by using a reciprocal tribometer without lubrication. Further milling tests are carried out to examine the cutting performances with sintered zirconia ceramics as workpiece comparatively. In friction test against zirconia ceramics, the monolayer NCD film shows the lowest friction coefficient (0.128) because of its smooth surface. Also, the bilayer diamond film with surface coating of NCD layer (MNCD) and both of the multilayer diamond films exhibit good friction property while the monolayer MCD film has the largest friction coefficient (0.292). The milling test demonstrates that the monolayer diamond (MCD and NCD) coated milling tools show poor tool life due to abrasive action of hard workpiece. Working life of all the bilayer and multilayer diamond coated tools is enhanced, but large area shedding of coatings appears after some milling passes except the multilayer diamond film with surface coating of NCD layer (MNMN-CD). The multilayer film (MNMN-CD) presents superior machining performance and its working life increases by 3–7.5 times compared with the monolayer diamond coated ones. Highlights • Diamond films with distinct multilayer structures are fabricated. • Multilayer diamond films are consisted of alternate MCD and NCD layers. • Multilayer diamond films exhibit good friction properties and low COF values. • Multilayer diamond films could improve the life of mills greatly. • Multilayer diamond coated mills show the best potential for zirconia machining. [ABSTRACT FROM AUTHOR]

Highlights • Two policies of carbon emission taxation rates are considered in the BQCAP: unitary taxation rate and piecewise taxation rate. • Two mixed-integer programming (MIP) models (Model Ⅰ and Model Ⅱ) for the BQCAP under two carbon emission taxation policies are developed. • A tailored branch-and-bound solution algorithm is proposed. • The effectiveness of different carbon emission taxation policies in reducing carbon emission is investigated and the impact of carbon emission taxation policies on the level of service of a port is evaluated. Abstract The environmental pollution issue of port has been highly concerned about by government and green port has been a focus to sustain the development of maritime transportation. At present, the port operator mainly takes measures of designing reasonable berth allocation for vessels and improving loading/unloading efficiency of quay cranes to reduce the carbon emission of port. The International Maritime Organization (IMO) has proposed to impose carbon emission tax on ports in the long-term, which would definitely enhance the willingness of ports to reduce the carbon emission. Therefore, this paper makes effort to explore the study of integrated berth allocation and quay crane assignment problem with considering two policies of different carbon emission taxation rates on port: one is unitary taxation rate and the other is piecewise taxation rate. Two corresponding mathematical optimization models are proposed for the two policies respectively and a number of equivalent or relaxed models are developed to ease the models. Finally, a set of test instances are randomly generated to access the applicability of the proposed models and an actual case is implemented to evaluate the effect of imposing carbon emission taxation on carbon emission reduction. It is found that the carbon emission taxation policy has significant effect on berth-QC plans and the carbon emission can be significantly reduced. [ABSTRACT FROM AUTHOR]

When drilling the carbon fiber reinforced plastics (CFRP), the tool shape and surface coating both play important roles in the cutting performance, which are complex and comprehensive, and should be systematically studied. In this research, WC-6wt.%Co drills in typical shapes are prepared, on which high-performance composite diamond films are deposited by the hot filament chemical vapor deposition (HFCVD) method. It is firstly proved by drilling tests that the tool shape always acts as a determining factor that significantly influences the drilling force and machining quality, for either the uncoated or diamond coated drills. The shorter chisel edge, smaller actual point angle and the proper double point angles are all factors in their favor. By contrast, as-deposited diamond films can slightly reduce the drilling force, while sometimes it even deteriorates the hole quality, due to the edge roundness caused by the alkali-acid pretreatment and the film growth. However, the diamond films play critical roles in improving the wear resistance, elongating the lifetime and guaranteeing the stability of the machining quality in the long-duration drilling process. In addition, the tool lifetime is also closely associated with the tool shape, attributed to the different thrust forces, consequently the lifetime of the diamond coated standard twist drill is much shorter than those of all other coated ones. [ABSTRACT FROM AUTHOR]

Tribological tests are conducted on diamond films under different lubrications, and influences of film type, lubrication, test parameters on coefficient of friction (COF) and film wear ( I d ) are studied. Diamond films perform better than WC-Co under water-based emulsion lubrication, and the boron doped micro-crystalline and nano-crystalline composite diamond (BDMC-NCCD) film shows the best overall behavior. Considering the performance and economy, the water content in the emulsion is optimized as about 80 vol%. Under this drawing condition, the quality of the production is similar to that drawn by the uncoated dies under the oil lubrication, however, the coated dies present much prolonged lifetime and lower temperature. Most importantly, the use of the water-based lubrication is much more environmentally friendly. [ABSTRACT FROM AUTHOR]

We constructed a series of novel chiral molecular face-rotating polyhedra (FRP) from two 10,15-dihydro-5H-diindolo[3,2-a:3′,2′-c]carbazole (triazatruxene) derivatives and trans-1,2-cyclohexane diamine, and investigated how facial interactions and the positions of substituents determine the diastereoselectivity and geometry of the final assemblies. [ABSTRACT FROM AUTHOR]

Based on the traditional deposition technique with the filament through the hole (DTFTH), the growth of high-quality diamond films on inner hole surfaces, especially those with small apertures, is rather difficult and laborious. In the present research, the deposition technique with no filament through the hole (DTNFTH) is proposed, and its feasibility and limitations are discussed on the basis of the radiation computation, temperature simulation, analyses on mean free paths of various active radicals, and the experimental verification of the “shading and distance effects”. It is indicated that the ratio of the hole depth to the hole diameter should be smaller than four. Afterwards, the drawing die with an aperture of 2 mm is designed, and a case study focusing on a single die and the mass production of diamond coated dies by the DTNFTH are both accomplished, using optimized deposition parameters. It is demonstrated that the film thicknesses are in the range of 4.8–6 μm (case study) and 3.5–5 μm (mass production), showing acceptable uniformity. Uncoated, DTFTH- and DTNFTH-diamond coated dies are all submitted to field tests, indicating that the lifetime of the DTFTH-diamond coated die is approximately eight times more than that of the uncoated one, while the DTNFTH-diamond film prolongs the lifetime of the uncoated die by a considerable factor of five. [ABSTRACT FROM AUTHOR]

In this study, the residual stress of boron-doped diamond (BDD) films is investigated as a function of boron doping level using X-ray diffraction (XRD) analysis. Boron doping level is controlled from 1000ppm to 9000ppm by dissolving trimethyl borate into acetone. BDD films are deposited on silicon wafers using a bias-enhanced hot filament chemical vapor deposition (BE-HFCVD) system. Residual stress calculated by method varies linearly from 2.4GPa to 1.1GPa with increasing boron doping level. On the BDD film of 1.75GPa, free standing BDD cantilevers are fabricated by photolithography and ICP-RIE processes, then tested by laser Doppler vibrometer (LDV). A cantilever with resonant frequency of 183KHz and factor of 261 in the air is fabricated. [ABSTRACT FROM AUTHOR]

The drilling performance of four typical types of single-layer diamond coated drills and two-layer boron-doped-microcrystalline/nanocrystalline diamond (BDMC-NCD) composite coated drill is compared, and the growth duration ratio of the NCD layer to the BDMCD layer ( N/B ) is optimized. It is demonstrated that the BDMC-NCD film synthesized using proper N/B shows nice adhesion, moderate diamond quality and a smooth surface mostly composed of nano-sized diamond grains, so it shows the best comprehensive performance, including the thrust force reduction, the improvement of the hole quality, the slowing of the tool wear and coating peeling, and the elongation of the tool lifetime. Taking the time of the coating peeling into consideration, 3/9 is the optimum N/B for the BDMC-NCD coated drill, and such the drill also performs the longest lifetime using delamination factors ( F d ) of 1.2 or 1.3 as the failure criteria. Moreover, the failure mode of the diamond coated drill is the flank wear when using F d = 1.1 or 1.2 as the failure criteria, while the tool failure should be related to the coating peeling when F d = 1.3. [ABSTRACT FROM AUTHOR]

Symmetry can be widely found in natural phenomenon. Regular polygons and polyhedra are the most basic and important symmetrical structures in 2D and 3D Euclidean space. Four-dimensional regular polytopes (4-RPs) are the 4D analogs of regular polyhedra in three dimensions and regular polygons in two dimensions. After introducing the fundamental root systems of 4-RPs, this article presents three interesting methods to visualize 4-RPs using a fundamental region algorithm. [ABSTRACT FROM AUTHOR]

This work considers the stochastic resource allocation problem for single-leg transportation markets with service disruptions. The single-period version of the problem is formulated as a stochastic model with arbitrarily distributed resource capacity. We then completely characterize the optimal solution to the stochastic model. The multi-period version of the problem is formulated as a dynamic programming model. We characterize the monotone structure of the optimal solution for the dynamic model under uniform resource consumption rates. For the case with general resource consumption rates, a counterexample is provided to show that there exist cases where the optimal solution is not monotone. [ABSTRACT FROM AUTHOR]

This paper investigates a dynamic resource allocation problem, in which an intermodal operator attempts to determine the policy that characterizes the optimal quantities of each service product allowed to be sold during each time interval within a finite selling horizon. The problem is formulated as a Markov decision process (MDP) model and a variety of mathematical programming models are developed to approximate the MDP model. A series of policies are obtained from the optimal solutions to the approximation models and theoretical results are provided to characterize the comparisons between the MDP model and the approximation models. Various policies are further evaluated through theoretical analysis and simulation tests. We finally gain insights into the importance of the dynamic decisions, stochastic demands, model re-solving, and integer variables in formulating approximation models. [ABSTRACT FROM AUTHOR]

Sandblasting combined with acid etching was utilized as pretreatment of Co-cemented tungsten carbide substrates for the deposition of chemical vapor deposition (CVD) diamond films. Diamond films were deposited on the pretreated surface as well as on substrates treated by a two-step alkali-acid pretreatment as a contrast. The field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Raman spectroscopy, Rockwell hardness tester and turning test were respectively conducted to characterize the pretreated substrates and deposited diamond films. Surface roughness of the treated surface was controlled by adjusting sandblasting parameters. An enhancement of surface roughness and removal of the binder phase were detected on the treated surface. The porous Co-depleted carbide layer caused by sandblasting and acid-etching pretreatment was obviously thinner compared to the two-step pretreatment. The nucleation stage of CVD process was investigated and the nucleation density was obviously enhanced by the sandblasting pretreatment. Indentation tests exhibited an improvement of adhesive strength compared to the two-step pretreatment. Moreover, the XRD patterns showed that the residual stress of diamond films was decreased. The turning tests showed that the diamond coated tools with sandblasting-acid pretreatment exhibited less area of flank wear and film shedding. [ABSTRACT FROM AUTHOR]

For the chemical vapor deposition (CVD) of diamond films, boron doping with appropriate boron doping levels can enhance the basic mechanical properties of the as-deposited films, especially the film-substrate adhesive strength. However, the boron doping level, which is thought to play a critical role in modifying the properties of the boron-doped diamond (BDD) film, must be further investigated. In the present investigation, the commonly used reaction-bonded silicon carbide (RB-SiC) material is selected as the substrate upon which boron-doped micro-crystalline (BDMCD) films with similar film thickness (24.8–26.3 μm) are synthesized using mixed reactant gas with different B/C atomic ratios, i.e., different boron doping levels. Systematic characterization and solid particle erosion tests are conducted on all specimens to elucidate the influence of the boron doping level on the diamond films' basic mechanical properties and erosion behavior and to elaborate the impact velocity and impact angle dependence of the erosion behavior. The results demonstrate that moderate boron doping levels (5000 and 8000 ppm) are able to maximize the growth rate, reduce the surface roughness, guarantee diamond quality and hardness, minimize the residual stress, and significantly enhance the film-substrate adhesive strength, thereby providing favorable erosion behavior. By contrast, very high boron doping levels (12,000 and 16,000 ppm) deteriorate the erosion behavior of as-deposited BDMCD films, mainly because of the excessive reduction of the film quality and hardness, together with the deterioration of the film-substrate adhesive strength caused by the transformation of the residual stress from compressive to tensile. With increasing either impact velocity or impact angle, the stable erosion rates of all specimens increase, and the film lifetime of the coated specimens become shorter. Moreover, the impact velocity dependence of stable erosion rates for diamond-coated specimens is considerably stronger than that for the uncoated RB-SiC specimen, as indicated by a much higher velocity exponent. [ABSTRACT FROM AUTHOR]

We consider a discrete intermodal network design problem for freight transportation, in which the network planner needs to determine whether or not to build up or expand a link to minimize the total operating cost of carriers and hub operators under a general route choice model of intermodal operators. We formulate the problem as a mixed-integer nonlinear and non-convex program that involves congestion effects, piecewise linear cost functions, and a fixed-point constraint. We develop a series of relaxed and equivalent models to reduce the hardness of the problem and provide theoretical results to show the equivalences. We present two solution methods to solve the problem with one returning heuristic solutions and the other generating a globally optimal solution. We offer two numerical experiments to test the two solution algorithms and also shed light on their performance comparisons. [ABSTRACT FROM AUTHOR]

Chemical vapor deposition (CVD) diamond films have been widely applied as protective coatings on varieties of anti-frictional and wear-resistant components, owing to their excellent mechanical and tribological properties close to the natural diamond. In applications of some components, the inner hole surface will serve as the working surface that suffers severe frictional or erosive wear. It is difficult to realize uniform depositions of diamond films on surfaces of inner holes, especially ultra-large inner holes. Adopting a SiC compact die with an aperture of Ф80 mm as an example, a novel filament arrangement with a certain number of filaments evenly distributed on a circle is designed, and specific effects of filament parameters, including the filament number, arrangement direction, filament temperature, filament diameter, circumradius and the downward translation, on the substrate temperature distribution are studied by computational fluid dynamics (CFD) simulations based on the finite volume method (FVM), adopting a modified computational model well consistent with the actual deposition environment. Corresponding temperature measurement experiments are also conducted to verify the rationality of the computational model. From the aspect of depositing uniform boron-doped micro-crystalline, undoped micro-crystalline and undoped fine-grained composite diamond (BDM-UMC-UFGCD) film on such the inner hole surface, filament parameters as mentioned above are accurately optimized and compensated by orthogonal simulations. Moreover, deposition experiments adopting compensated optimized parameters and some typical contrastive parameters are also accomplished for further verifying the rationality of the computational model and the correctness of the compensation coefficient 0.7 defined for the downward translation determined by simulations. More importantly, on the basis of more simulations and verification tests, a general filament arrangement model suitable for Ф50–120 mm circular inner holes is determined, involving all above filament parameters that are functionally dependent on the diameter of the inner hole. [ABSTRACT FROM AUTHOR]

We study the seat allocation problem for passenger rail revenue management, in which a rail operator attempts to determine the optimal quantity of seats to be allocated to each cabin class for each train service. We formulate the problem with single-stage and multi-stage decisions as two stochastic programming models that incorporate passengers’ choice behavior. We transform the stochastic models into equivalent deterministic mathematical programs that are easy to solve. Then, we form a variety of seat allocation polices from the optimal solutions to the seat allocation models. A number of simulation tests are offered to test the policies. [ABSTRACT FROM AUTHOR]

The sailing speed optimization problem aims to determine the optimal cruising speeds of ships by balancing the number of ships required on services, the fuel consumption, and the level of service provided for customers. The level of service can be incorporated into a sailing speed optimization model from the perspective of supply chain management or from the perspective of shipping lines. We design a polynomial-time algorithm workable to solve the two models based on bi-section search methods. The novelties of the algorithm include constructing a new parameter on which the bi-section search will be executed and deriving a near-optimal solution by taking advantage of the problem structure. We also provide theoretical results that guarantee the validity of the polynomial-time algorithm. [ABSTRACT FROM AUTHOR]

We consider the resource allocation problem with discrete random demands and discrete random resource capacities for standardized cargo transportation networks, in which a freight operator needs to determine the integral quantity of booking requests to be accepted for each product to maximize the expected profit. We formulate the problem as a stochastic integer programming model and provide theoretical results that completely characterize the optimal solution to the stochastic model under a special case. We present a progressive augmentation algorithm and a sampling based method for solving the stochastic model under a general case. We also offer numerical experiments to test the two methods and shed light on their performances. [ABSTRACT FROM AUTHOR]

We consider the stochastic resource allocation problem for containerized cargo transportation with uncertain capacities and network effects, in which a freight operator needs to allocate a certain amount of capacity to each product to maximize the expected profit. We formulate the problem as a constrained stochastic programming model and provide theoretical results that completely characterize the optimal solution to the model under a special case. Under a general case, we build an approximation model of the problem and propose a sampling based algorithm to solve the approximation model. A number of numerical experiments are offered to test the algorithm. [ABSTRACT FROM AUTHOR]

Micro-crystalline diamond (MCD) films are deposited on reactive sintering SiC substrates by the bias enhanced hot filament chemical vapor deposition (BE-HFCVD) method, respectively using the methane, acetone, methanol and ethanol as the carbon source. Two sets of standard tribotests are conducted, adopting Si 3 N 4 balls as the counterpart balls, respectively with the purpose of clarifying differences among tribological properties of different MCD films, and studying detailed effects of the carbon source C , normal load F n and sliding velocity v based on orthogonal analyses. It is clarified that the methane-MCD film presents the lowest growth rate, the highest film quality, the highest hardness and the best adhesion, in consequence, it also performs the best tribological properties, including the lowest coefficient of friction ( COF ) and wear rate I d , while the opposite is the methanol-MCD film. Under a normal load F n of 7 N and at a sliding velocity v of 0.4183 m/s, for the methane-MCD film, the maximum COF ( MCOF ) is 0.524, the average COF during the relatively steady-state regime ( ACOF ) is 0.144, and the I d is about 1.016 × 10 −7 mm 3 /N m; and for the methanol-MCD film, the MCOF is 0.667, the ACOF is 0.151, and the I d is 1.448 × 10 −7 mm 3 /N m. Moreover, the MCOF , ACOF , I d and the wear rate of the Si 3 N 4 ball I b will all increase with the F n , while the v only has significant effect on the ACOF , which shows a monotone increasing trend with the v . [ABSTRACT FROM AUTHOR]

This study aims to propose a tangible approach to delimiting the probabilistic hinterland of a port of interest. We first build a geometric model for the probabilistic port hinterland based on intermodal network flows jointly using discrete choice analysis and geographical information of shippers. We further design an algorithm that can efficiently determine the hinterland boundaries using the sample approximation of shippers’ choice probabilities. We provide theoretical results that characterize the minimum computational effort required to achieve a certain degree of accuracy in the sample approximation. We also offer two numerical case studies to justify the proposed approach. [ABSTRACT FROM AUTHOR]

Mechanical properties and solid particle erosion of chemical vapor deposition (CVD) diamond films are strongly influenced by the adopted carbon source in the deposition process. In the present study, methane, acetone, methanol and ethanol are respectively used as the carbon source to deposit micro-crystalline diamond (MCD) films on SiC substrates by the bias-enhanced hot filament CVD (BE-HFCVD) method. A standard air–sand erosion rig is employed to conduct erosion tests, using angular SiC sands of 320 meshes as impact abrasives. The impact velocity v e and impact angle α e are fixed as 100 m/s and 90°, respectively. The steady-state erosion rate ε s , film life t r and a unit film life t ru are defined to assess the erosion behaviors of as-deposited films, which have close relationships with the mechanical properties, as measured by the Rockwell hardness tester and the nanoindentation test. It's found that under the condition of the same film thickness, the methane-MCD film shows the lowest ε s and the longest t r , owing to the highest surface hardness and the most favorable film-substrate adhesion which is equivalent to the highest fracture strength, but the opposite is true for the methanol-MCD film. Moreover, due to the relatively higher growth rate, the acetone- and ethanol-MCD films both perform even longer t ru than the methane-one, indicating better “average” erosion behavior. Consequently, the optimal efficiency and economy can be achieved when adopting either the acetone or the ethanol to deposit MCD films of sufficient thickness on working surfaces of erosion resistant components suffering severe erosive wear, especially in the case of mass production. [ABSTRACT FROM AUTHOR]

The differences between the nucleation, growth and basic characteristics of bias-enhanced hot filament chemical vapor deposition (BE-HFCVD) microcrystalline diamond (MCD) films fabricated under the different carbon source (methane, acetone, methanol and ethanol) environments are studied in this article, adopting SiC chips as substrates. With the same commonly-used nucleation parameters, acetone and ethanol can provide either higher nucleation density ( ND ) or larger nuclei size ( NS ). Besides, under the same commonly-used growth conditions, relatively higher growth rate ( R ) of the MCD film is obtained adopting methanol than methane, and both acetone and ethanol can further increase it. Moreover, as characterized by the X-ray Diffraction (XRD) and Raman spectroscopy, the MCD film fabricated using methane shows much lower total residual stress ( σ ), better film quality and lower (220)/(111) ratio compared with those fabricated using all the other carbon sources. The above results can be attributed to the presence of oxygen elements, the different dissociation energies of chemical bonds in the carbon sources, the different quantities of CH 3 radicals generated from the carbon sources or the different amounts of defects in as-deposited diamond films. Based on the present study, it is suggested that the carbon source should be reasonably chosen in order to, respectively, improve the film quality or obtain high ND , NS and R . [ABSTRACT FROM AUTHOR]

HFCVD diamond films have been extensively applied on inner-hole surfaces of some wear resistant components as protective coatings, the mass production of which puts forward a high request to the HFCVD equipment. In this paper, adopting a typical kind of drawing die as the substrate, several different substrate configurations are proposed to expand the capacity of the equipment. Temperature distributions on inner-hole surfaces of the substrates are respectively predicted and compared by the finite volume method (FVM) simulations. In summary, for parallel configurations, proper-designed auxiliary devices (e.g. the heat-insulated plate, the water-cooled plate and the heat-insulated cushion block) can provide sufficient effects on the uniformity of the substrate temperature distribution. Moreover, without any auxiliary devices, homogeneous substrate temperature distributions can also be obtained using circular pattern configurations (radial, hexagon and triangular). Accordingly, the HFCVD equipment referring to the design concept of the triangular configuration is trial-manufactured. In the verification experiments, similar substrate temperature values are detected in three different modules, and as-deposited microcrystalline diamond (MCD) and nanocrystalline diamond (NCD) films both present uniform grain size, thickness and quality, well validating the rationality and correctness of the simulation-based optimal design. [ABSTRACT FROM AUTHOR]

Abstract: Chemical vapor deposition (CVD) diamond film has been considered as a good candidate protective coating under hostile and abrasive conditions due to its outstanding erosion behavior. In the present study, the conventional micro-crystalline diamond (MCD) film, nano-crystalline diamond (NCD) film and the boron-doped diamond (BDD) film are respectively fabricated by the hot filament CVD (HFCVD) method. Solid particle erosion tests are conducted on diamond films in an air–sand erosion rig under different impact velocities (v) and angles (α) with angular SiC sands as the erodents, and WC–Co and SiC materials are adopted as comparisons. The field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Raman spectroscopy, Rockwell hardness tester and surface profilometer are respectively used to characterize diamond films before and after tests, exhibiting that compared with MCD and NCD films, the BDD film performs relatively higher fracture strength and better adhesion. Typical solid impact erosion stages of the different diamond films are observed. The solid particle erosion behavior of diamond films has close relationships to their fracture strength and adhesion. As a result, when the impact angle α ≤30°, the steady-state erosion rate of the BDD film is lower than those of MCD and NCD ones. More importantly, under all the impact angles and velocities, much quicker film delamination and removal can be noticed on the MCD and NCD films, especially the NCD one. By contrast with WC–Co and SiC materials, diamond films present much better erosion resistance and higher velocity exponents, which should be attributed to different impact mechanisms caused by the different hardness of eroded samples. [Copyright &y& Elsevier]

Abstract: Chemical vapor deposition (CVD) diamond film has extensively applied as the protective coating under hostile and abrasive conditions, the erosion mechanism of which is significantly influenced by the composition and thickness of the film. This paper describes an erosion study, which examines the effects of the film thickness on the erosive wear behavior of the boron-doped diamond (BDD) films deposited on the SiC substrates by the hot filament CVD (HFCVD) method, with the undoped ones as comparisons. A laboratory designed air–sand erosion rig is used to conduct the erosion tests, with the velocities in the range of 100–140m/s and 90° nominal impact angle. The erodents are silica sands with an average diameter of 180μm. The diamond films are examined both pre- and post-test by the field emission scanning electron microscopy (FESEM) in order to determine the erosion mechanisms of the diamond films. Firstly, it is observed that the higher residual compressive stress and critical tensile strength can slow down the formation of the ring cracks. Moreover, the 12μm diamond film has the highest steady-state erosion rate because the depth of the maximum shear stress is much close to the film–substrate interface. Furthermore, the complicated effects of the film thickness on the film lives of both the BDD and undoped diamond films are also further studied, as well as the velocity exponents of the different diamond films. The research results in the present study are conductive to the widespread applications of BDD films on the erosion resistant components. [Copyright &y& Elsevier]

Nitrogen doped diamonds with great application potentials can be synthesized by using different doping sources (i.e., urea and N 2), effects of which on growth behavior and properties of diamond films on WC-Co substrates were presented in this paper. The doping efficiency of urea was always higher than 0.12, much higher than that of N 2 (always lower than 0.04). The sufficient N 2 addition could increase growth rate, and induce apparent grain nanocrystallization, by modifying reactant gas phase chemistry. The grain nanocrystallization contributed more to the reduction of the surface roughness, and degradation of the diamond purity and mechanical properties. On the contrary, the urea doping resulted in much less degradation of the diamond purity and mechanical properties, while providing sufficient N incorporations into the diamonds. Besides, urea doping promoted the formation of the diamond (220) planes on the polycrystalline diamond surfaces, which had a close relationship with the actual N doping concentration in the diamond. The controllable adjustment of the growth and properties of diamond films, by selecting the doping source and optimizing the doping ratio, could help to meet distinctive application requirements, and balance the machining efficiency and application performance of diamond coated components. [Display omitted] • Urea and N 2 of different concentrations are adopted as nitrogen doping sources. • Doping efficiency by using urea is higher. • Two doping sources deteriorate diamond quality and mechanical properties by different means. • Influences of urea on diamond quality and mechanical properties are much less severe. • Mechanical properties can be adjusted by optimizing N doping source and ratio. [ABSTRACT FROM AUTHOR]

Abstract: Recently, shaped drawing dies with complicated hole shapes have attracted intensive interests to produce shaped wires. In order to produce high-quality wires, the surface smoothness of the drawing dies is a major requirement and as important as the wear resistance. In the present investigation, the deposition parameters in diamond films growth on the interior-hole surfaces of the WC–Co rectangular-hole shaped drawing dies are optimized by orthogonal simulations, for which homogeneous substrate temperature (dT <15°C) and gas density fields are obtained. Thereafter, boron-doped diamond (BDD) films are fabricated and characterized, showing that high-quality films with uniform thickness (24–25μm) have been deposited on the whole interior-hole surface. Compared with the undoped diamond film, the BDD one presents much better adhesion and long-tested wear resistance. Moreover, the BDD film is also much easier to be polished to the appropriate surface smoothness due to the grain refinement and hardness reduction. Particularly, by comparison to the WC–Co drawing die, the working lifetime of the BDD coated one increases by a factor of above eight and in the course of processing, copper rectangular wires with higher surface quality and better dimensional precision are obtained. [Copyright &y& Elsevier]

Abstract: The boron-doped (B-doped) and silicon-doped (Si-doped) diamond films are deposited on Co-cemented tungsten carbide (WC–Co) drills by the hot filament chemical vapor deposition (HFCVD) method, adopting trimethyl borate (C3H9O3B) and tetraethyl orthosilicate (C8H20O4Si) as the dopant sources, respectively. The characterization of as-deposited diamond films are investigated by scanning electron microscopy (SEM) and Raman spectroscopy. The adhesive strength between the diamond films and the WC–Co substrates is assessed by Rockwell indention tests. The drilling tests for evaluating the performance of the diamond coated drills are conducted with carbon fiber reinforced plastics (CFRP) as the workpiece. For the sake of comparison, conventional diamond coated and bare WC–Co drills are also used in the drilling tests. The wear performance of the tools is compared and discussed in terms of the diamond coating microstructure. According to the results, the diamond coated drills exhibit a better wear resistant with respect to the uncoated one. Besides, the Si-doped diamond coated drill displays the best cutting performance for the smooth surface and favorable adhesive strength. [Copyright &y& Elsevier]

Abstract: LiNbO3 films were grown on nanocrystalline diamond (NCD)/Si substrates with amorphous SiO2 buffer layer by pulsed laser deposition technique at various oxygen pressures ranging from 10Pa to 80Pa. The stoichiometric LiNbO3 ceramic target was used. Significant effects of oxygen pressure on c-axis orientation, stoichiometry, crystallinity and surface morphology of LiNbO3 films were investigated. It was found that the above properties are strongly dependent on the oxygen pressure. Completely c-axis oriented LiNbO3 films with the average surface roughness of 9.0nm could be achieved under an optimum oxygen pressure of 40Pa. Surface acoustic wave devices were fabricated and characterized utilizing the structure of LiNbO3/SiO2/NCD/Si. [Copyright &y& Elsevier]

Abstract: In the present study, adopting the optimized deposition parameters determined by orthogonal simulations, high-quality boron-doped and undoped composite diamond (BD–UCD) films with uniform thickness are deposited on both the inner hole and conical surfaces of the SiC nozzles used in the spray drying equipment. The erosion behavior of the novel diamond film is firstly evaluated in an air–sand erosion rig, with single-layer boron-doped diamond (BDD) and undoped diamond films as comparisons. Thereafter, the erosive wear performance of the BD–UCD coated nozzles is further studied under the industrial condition. The results show that the BD–UCD film exhibits an apparent increase in the erosion resistance over the other two types of diamond films. The mechanism responsible is found to be that the surface undoped diamond layer in the BD–UCD film has outstanding hardness, and boron doping can improve the adhesion between the underlying BDD layer and the substrate. Moreover, under the industrial condition, the ethylene catalytic cracking catalyzers produced with the BD–UCD coated nozzles have much more stable quality than those produced with the uncoated nozzles owing to the aperture stability of the inner hole, further proving the high erosion resistance of the BD–UCD protecting coatings. [Copyright &y& Elsevier]

Abstract: The micron well-faceted diamond powders have attracted an increasing attention in the polishing filed, owing to improve the surface finish of components using the powders. In the present work, the hot filament chemical vapor deposition (HFCVD) technique is employed for synthesizing such diamond powders. A great many of micron diamonds are grown simultaneously but independently onto a large-area substrate. First, a novel seeding method, spraying the diamond seeds suspension toward the substrate using a spin coater machine, is proposed, with which the seeds with a controlled density are distributed evenly onto the substrate. Also, the method is more suitable for the fabrication of the micron isolated diamonds, compared with other nucleation initiation methods, such as the scratching pre-treatment and electrical biasing on substrates. Afterwards, a systematic investigation is under taken into the effects of deposition parameters on the basic growth characteristics of CVD micron diamonds, and on the inhibition of films growth. Furthermore, the reactive pressure, substrate temperature, carbon concentration, and growth duration are determined to be 4500Pa, 850°C, 1.3–1.4%, 60–90min, respectively. Eventually, under the preferred deposition conditions, approximately 15 million cube-octahedral crystals with the mean size of 2–3μm are deposited simultaneously on the 1000mm2 substrate. [Copyright &y& Elsevier]

Abstract: Pure and Ni-doped ZnO nanofibers were synthesized using the electrospinning method. The morphology, crystal structure and optical properties of the nanofibers were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy, respectively. It is found that Ni doping does not change the morphology and crystal structures of the nanofibers, and the ultraviolet emissions of ZnO nanofibers present red shift with increasing Ni doping concentration. C2H2 sensing properties of the sensors based on the nanofibers were investigated. The results show that the C2H2 sensing properties of ZnO nanofibers are effectively improved by Ni doping, and 5at% Ni-doped ZnO nanofibers exhibit a maximum sensitivity to C2H2 gas. [Copyright &y& Elsevier]

Abstract: The substrate temperature distribution in HFCVD diamond film growth on the inner hole surface is simulated by the finite volume method in the present study, adopting a detailed 3-D computational model agreeing with the actual reactor. Firstly, the influences of several key deposition parameters are studied by the control variable method, including the cooling condition C, the filament temperature Tf , the filament diameter d and the substrate aperture D. Afterwards, the substrate temperatures in the actual reactor are measured. Deviations between the simulated and measured temperature values are all less than 5%, and the substrate temperature distribution trends in the measurement results are well coincident with those in the simulation results. Furthermore, corresponding deposition experiments are also conducted, the results of which can further validate the correctness of the simulations. Finally, the optimized deposition parameters are used to deposit diamond films on the inner hole surfaces of the WC–Co substrates with apertures of either 6mm or 8mm. The characterizations show that homogeneous diamond films with fine-faceted diamond crystals are obtained, indicating that this deposition parameter optimization method is feasible for fabricating high-quality diamond films on the inner hole surfaces. [Copyright &y& Elsevier]

Abstract: Undoped and Al-doped ZnO nanofibers were synthesized via a simple electrospinning method, and then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman scattering and photoluminescence (PL) spectroscopy. The ethanol sensing properties of the sensor based on the nanofibers were also investigated. The results show that the sensor fabricated from Al-doped ZnO nanofibers exhibits better gas sensing performance than that fabricated from the undoped ZnO nanofibers, and the gas sensing mechanism is discussed. [Copyright &y& Elsevier]

Conductive polymer polypyrrole (PPy)-coated lithium-rich manganese-based Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) nanotube cathode materials were synthesized by electrospinning and subsequently subjected to low-temperature vapor-phase polymerization. X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) results confirm that the successful coating of the PPy layer (~2 nm) on the surface of LMNCO nanotubes did not destroy their morphologies or structures. Electrochemical tests indicate that the electrochemical performance of PPy-coated LMNCO nanotubes has been significantly enhanced. At a rate of 1 C, the discharge capacity of the PPy-coated LMNCO cell is 200.1 mAh g−1, and the capacity retention is 99% after 120 cycles. This excellent stability is attributed to the inhibition of side reactions and the protective function of the tubular structure due to the PPy coating layer. Additionally, the rate capability is also improved at a high current density due to the higher electronic and ionic conductivity. [ABSTRACT FROM AUTHOR]