Search

Understanding the compositional dependence of properties of silicate glass is critical to design novel glasses for various technology applications. With the development in molecular dynamics simulations and machine learning techniques, a combined and fully computational approach, which is able to reveal the relationship between glass composition and its mechanical properties, can be developed and served as a guide prior to experiments and manufacturing. On one hand, machine learning is a powerful tool to predict the properties based on the existing database. On the other hand, molecular dynamics simulation cannot only produce sufficient data points for machine learning models but also provide a detailed picture of the atomic structure of glasses. This atomic-scale knowledge from molecular dynamics simulation contains an intrinsic relationship between glass compositions and their mechanical properties.Here, we first use molecular dynamics simulation to generate the dataset for calcium aluminosilicate glasses and apply different machine learning models to predict their Young’s modulus using glass compositions in Chapter 1. Next, we apply topological constraint theory to quantify the atomic structures of simulated glasses and use this knowledge to predict Young’s modulus for calcium aluminosilicate glass family in Chapter 2. Last, in Chapter 3, we propose a fully analytical model to link the network topology with glass compositions.

Taking the two-phase flow mixing process in the top-blown gas stirred tank as the research object, a new strategy extracting the chaotic characteristics of the two-phase mixing state is proposed. By quantifying the local mixing characteristics in the top-blown metallurgical furnace stirring simulation reactor, a new chaos detection method combining complete ensemble empirical modal decomposition with adaptive noise (CEEMDAN) and 0–1 test is introduced to characterize the chaotic characteristics of mixing index time series. The results show that (1) the uniformity coefficient (E) is better than the Betti number in quantifying the mixing uniformity of the two-phase flow. (2) E m a x can better quantify the uniformity of two-phase mixing. (3) The mixing time can be decreased when the optimal gas flow rate and the length of the submerged pipeline are correctly selected. (4) By using the CEEMDAN to decompose the time series, the chaotic characteristics of different IMF components under different working conditions can be observed straightforwardly. (5) The difference of chaotic degree in different mixing processes can be more accurately characterized. The investigation reference on the flow and mixing characteristics of the top-blown metallurgical furnace can be provided further.

Dual-ion batteries (DIBs) inherently suffer from limited energy density due to insufficient anion storage capacity of typical graphite cathodes. Herein, we propose a new design strategy to effectively tackle this issue via employing locally ordered graphitized carbon (LOGC) cathodes. Quantum mechanical modeling suggests that strong anion-anion repulsion and severe expansion at the deep-charging stage raise the anion intercalation voltage, therefore only part of the theoretical anion storage sites in graphite is accessible. The LOGC interconnected with disordered carbon is predicted to weaken the interlaminar van der Waals interaction, while disordered carbons not only interconnect the dispersed nano-graphite but also partially buffer severe anion-anion repulsion and offer extra capacitive anion storage sites. As a proof-of-concept, ketjen black (KB) with the typical feature of LOGC is selected as a model cathode for a potassium-based DIB (KDIB). The KDIB delivers an unprecedentedly high specific capacity of 232 mAh g -1 at 50 mA g -1 , a good rate capability of 110 mAh g -1 at 2000 mA g -1 and excellent cycling stability of 1000 cycles without obvious capacity fading.

Recycling graphite from spent LiFePO4 batteries plays a significant role in relieving the shortage of environmental protection and waste of valuable resources. However, a low initial coulombic efficiency (ICE) and poor performance at a high current density frustrate its practical application. In this study, a brief method is proposed to recycle spent graphite (SG) via gas-phase oxidation. The electrochemical performance of the oxidation spent graphite (OSG) with different calcination temperatures (450 °C, 550 °C and 650 °C) and times (1 h, 2 h and 3 h) were carefully studied. The ICE of OSG increases first and decreases as the temperature increases, and increases with the extension of calcination time. OSG was prepared by holding for 3 hours at a 550 °C calcination temperature. As an anode for lithium-ion batteries, OSG-550-3 exhibits a remarkable electrochemical performance in terms of ICE (86.9%) and first irreversible capacity (61.1 mA h g−1) compared to those of the SG electrode (64.4% and 186 mA h g−1, respectively). The improvement is attributed to removal of some highly active sites or defects, which weaken the damage effect of solvent molecule co-embedding during the charge/discharge process. The present work highlights the critical roles of gas oxidation in the development of SG anodes for lithium-ion storage.

To end the elimination the harm to the environment of spent carbon anode (SCA), which is a hazardous solid waste from the aluminum reduction cell, the SCA is treated by the alkali fusion method and the purified SCA (PSCA) is evaluated as the anode of Li ion batteries (LIBs) for the first time. In this work, the alkali fusion technologies are optimized using the single factor experiment and the orthogonal tests (L9 orthogonal array). And the best carbon content can reach 99.10% when the reaction temperature is 600 °C, reaction time is 6.5 h, and NaOH / SCA mass ratio is 5.5 ∶ 1. Evaluation of the importance of the effects of key parameters was performed using analysis of variance (ANOVA). The PSCA shows the abundant layered structure and pores. It is composed of amorphous carbon and graphitized carbon with an average carbon layer spacing of 0.3398 nm. The PSCA exhibits a considerable reversible capacity of 286.8 mAh/g at 1 C and a good capacity decay rate (a decay rate per cycle of 0.030% in 500 cycles) which are much higher than those of commercial soft carbon (213.7 mAh/g and 0.039%). It is demonstrated that SCA can be transformed into a potential anode of LIBs after purification, and this sustainable approach can easily be extended to the recovery and utilization of other carbonaceous solid waste.

The effects of hydrogen evolution reaction on the deformation of zinc anode which cycles at nearly 100% depth of discharge (DOD) are studied. Results show that the generated hydrogen bubbles during charging process will gather on the surface of the middle of the anode and will cover the ZnO which is produced by the hydrolysis of Zn (OH)42− and prevent ZnO participation in the charging process. Since the charge-discharge reaction only occurs at the edges of the bubbles, the multiple dissolution and redeposition of the active material results in the formation of a massive ZnO and a very low specific discharge capacity. This finding provides a new perspective for the deformation of zinc anodes of the secondary alkaline zinc-based batteries.

Phenyl molybdate-modified phenolic fibers (PMoPFs) were prepared by melt spinning from the corresponding resin which was polymerized from phenol, formaldehyde, and phenyl molybdate, followed by solution curing and then heat curing processes. The molecular structures, including characteristic groups and molecular weight, were examined by nuclear magnetic resonance, Fourier transform infrared spectroscopy, and gel permeation chromatography. The influences of the curing processes were demonstrated by mechanical properties, scanning electron microscopy, and thermogravimetric analysis characterization. PMoPF with 8 wt% molybdic acid and cured in an oven possessed a tensile strength as high as 187 MPa, initial decomposition temperature of 300°C, and a char yield under nitrogen atmosphere at 800°C as high as 66.0%, with the molybdate (MoO4 2−) groups being introduced into the phenolic main chain.

Plasmon induced transparency (PIT) in the transparent window provides new insights into the design of optical filters, switches and storage, and integrated optics. The slow light effect makes PPIT applicable to both sensors and slow light devices. Besides, PPIT can overcome the diffraction limit of light, which makes it possible to manipulate light on a half-wavelength scale and brings good news to the miniaturization of optical devices. In this paper, we first summarize the researches of Pit phenomenon based on metal-dielectric-metal (MDM) waveguide systems and analyze the physical mechanisms of Pit including bright-dark mode interactions and phase-coupling-induced transparency. Then, we review the applications of Pit in optical sensing, optical filtering, optical switching, slow light devices and optical logic devices. At last, we outline important challenges that need to be addressed, provide corresponding solutions and predict important directions for future research in this area.

The amorphous porous layered-Al2O3 derived from aluminium fumarate metal-organic frameworks (AlFu MOFs) by roasting at 773 K under air has been applied to remove fluorine ions from industrial ZnSO4 solution. The amorphous porous layered-Al2O3 was characterized by XRD, SEM and BET. The adsorption experiments were conducted under different conditions, including adsorbent dosage, initial pH, adsorption temperature and adsorption time. And the process of removing fluorine ions is well fitted with the pseudo-second-order kinetic model and Langmuir isotherm model, which is studied by the adsorption kinetics and isotherms. The theoretical maximum adsorption capacity was 12.05 mg g−1. Moreover, the adsorption mechanism of the amorphous porous layered-Al2O3 was analyzed by SEM-EDS and FTIR. The results indicate that the adsorption process is affected by complexation and ion exchange between fluorine ions and amorphous porous layered-Al2O3. The regeneration of the amorphous porous layered-Al2O3 shows that the adsorbent could be reused to reduce the production cost.

Spent carbon cathode (SCC), a hazardous solid waste generated from the primary aluminium industry, is successfully purified by a graphitization process to eliminate the environmental damage. The purity of as-abtained carbon from SCC increases from 63.64% to 100% and shows uniform and high graphitization, the fine graphitized carbon with defects, the partial hollow structures, the slightly expanded interlamellar spacing (0.34–0.37 nm) and a small amount of graphene structure. When SCC-2600 is used as an anode material for LIBs, it shows good reversible capacity (460.1 mAh g−1 at 0.1 C after 50 cycles), excellent rate capability (430.2, 388.6, 353.5, 287.3, 111.1 and 68.2 mAh g−1 at 0.1, 0.5, 1, 2, 5, and 10 C, respectively). And then, SCC-2600 reveals a potential high-capacity anode material for LIBs in comparation with the low voltage plateaus (

The evaluation of the mixing effect of gas-liquid two-phase flow during the top-blown gas agitation mixing is one of the difficulties in the testing field, especially in the process of using the model method to study the metallurgical top-blowing process. In order to evaluate the effect of gas-liquid two-phase flow mixing, a gas chromatography simulation based on capacitance tomography was used to visualize the flow pattern and analyze the mixed characteristics. A gas top-blown agitation test rig was set up, the gas phase was air-selected, and the liquid phase was selected from synthetic heat-conducting oil. The top-blown stirring test process was measured and imaged by electrical capacitance tomography (ECT) equipment from ECT Instruments Ltd (UK). The MATLAB program was used to identify the mixing areas of the images to obtain the distribution of gas-liquid two-phase. The flow pattern of the gas-liquid mixing region was obtained. The chaotic detection of the gas-liquid mixing process was performed by the three-state test method; the images were processed by the counting box dimension-corrosion method to obtain the mixing uniformity time of gas-liquid flow. Results show that it is feasible to use the capacitance tomography technique to visualize the gas-liquid two-phase distribution. The uniformity time quantification of the gas-liquid mixing process is also achieved.

Nano-modified indium tin-oxide (ITO) glass substrates are fabricated for an internal light-extraction structure to enhance the out-coupling efficiency of green organic light-emitting diode (OLED) devices. This nano-modified anode with low haze was prepared by wet chemical etching. Polystyrene (PS) hemispheres, which were distributed randomly on the ITO anode surface, were used as the etching mold. With the help of nano-modified ITO glass substrate, the light trapped by the internal waveguide mode can be extracted effectively compared with conventional planar OLED devices. When OLED devices are incorporated with a nano-modified ITO anode, the highest enhancements of current efficiency (CE), power efficiency (PE) and external quantum efficiency (EQE) are about 40.7%, 37.1% and 36.9%, respectively, relative to a standard device without any light out-coupling structure in the forward direction. To further improve the performance of OLED devices, an ideal microlens array (IMLA) is introduced to the air-side of the glass substrate to extract substrate waveguide. With both internal and external out-coupling structures, the CE, PE and EQE of OLED devices are enhanced by 101.5%, 100% and 96%, reaching 119.3 cd A−1, 108.8 lm W−1 and 31.4% in the forward direction, respectively. Moreover, the nano-modified ITO anode with low haze has no detrimental effect on the performance of OLED devices and is suitable for lighting and display application.

A micro soldering method based on micro gripping was developed to improve strength between bonding pad and wire. The designing and working principle of micro soldering set-up were based on micro gripper and microscopic vision guided motion of soldering iron tip. Strength comparative experiments between unsoldered and soldered bonding joints were conducted to demonstrate the bonding strength improvement brought by micro soldering procedure. X-ray microscopic computed tomography (CT) scanning results show maximum void diameter in the soldered binding joint is 97.905 µm.

The bamboo scrimber has been widely used in building materials and interior decoration. However, the bamboo scrimber is very vulnerable to mold due to the rich nutrients in bamboo parenchyma cells. In this study, a thermal treatment with saturated vapor was employed to improve the mold-proof property of bamboo scrimber. Four kinds of mold (Botryodiplodia theobromae, Aspergillus niger, Penicillium citrinum, Trichoderma viride) were respectively used to infect the original bamboo scrimber (OBS) and thermally treated bamboo scrimber (TBS). The TBS presents better mold-proof property than the OBS, especially to T. viride. After 28-day infection, the TBSs infected area ratio reached 10.3 % with a remarkable decline compared with the OBS (45 %). In addition, no obvious discoloration was observed on the TBS after infection by B. theobromae. The obtained results show that the degradation of hemicellulose in bamboo bundles during thermal treatment mainly contributes to the enhancement of mold-proof property. The TBSs enhanced hydrophobicity also takes responsibility for slowing down the growth of mycelium. This study exhibits a simple, green and cost-effective method to effectively improve the mold-proof property for the bamboo scrimber without any extra mold inhibitors.

A novel die sorter based on mechanical gripper was developed for picking and placing diced terahertz Schottky barrier diodes (SBD). The designing and working principle of die sorter are based on flexible hinge and linear-actuator. Dimensions of dies gripped by the sorter can be as small as 100 µm * 50 µm* 15 µm without damage to its air-bridge. For flipping upside down dies, the rotation motion was obtained by rotating linear actuator about its shaft. It is demonstrated that the placement accuracy of the sorter can achieve less than 9.5 µm and 3.0 µm in x-y direction respectively.

In this work, a novel stirring strategy that chaotic-speed with Logistic-Logistic cascade sequence (CS-LLCS) is proposed to enhance the solid-liquid mixing state quality. Specially, the effects of stirring strategy, peak level (npvcs) and speed changing time (tsct) of CS-LLCS stirring on the mixing state quality of the fluids in a stirred tank are focused on to illustrate it. Moreover, a modern time series analysis method (i.e., chaos decision tree algorithm) is introduced to extract the characteristics of the fluids chaotic mixing for the first time. Results show that not only the mixing time of CS-LLCS stirring is shortened by 35.11% and 57.70%, but also the mixing power consumption is reduced by 58.36% and 78.55% compared with bidirectional-speed stirring (BS stirring) and constant-speed stirring (CS stirring). The stirring performance is optimal when npvcs is set to 140 r/min and tsct is set to 3 s. The mixing state quality can be powerfully improved by the CS-LLCS stirring resulting from disturbing the periodic motion of the vortices and increasing the interfacial area of immiscible liquids. Furthermore, the mean value Kc∗(n) of the asymptotic growth rates of the mixing process is proposed as a chaotic indicator which can be more accurately to characterize the difference changes of chaos degree in various chaos mixing processes. Hence, the energy transfer efficiency would be enhanced by the chaotic-speed stirring strategy with Logistic-Logistic cascade sequence.

The pattern complexity (kinetics and uniformity) of bubble swarms governs the heat transfer performance in gas-liquid contact systems such as direct-contact boiling heat transfer process. An image analysis technique is developed for quantifying the complexity evolution of bubble pattern in the gas-liquid contact system based on entropy theory and algebraic topology (more precisely, Betti numbers) using organic Rankine cycle direct-contact heat exchangers. The Betti numbers method is associated with image segmentation using entropy theory, leading to a useful model to characterize the homogeneity of the mixture. Experimental results show such an effectiveness. This novel method may be applied the study of a variety of multiphase flows.

Bi2O3@ZnO sphere is prepared by solvothermal and proposed as an anode material for Zn-Ni battery, which shows a high discharge specific capacity and cyclic stability. The discharge specific capacity remains at a high level of 608.6 mAh g−1 after cycling 160 cycles at 1 C and the average specific capacity is up to 604.9 mAh g−1, which is more excellent than pure ZnO. This striking property is attributed to the homogeneous distribution of Bi2O3 in Bi2O3@ZnO sphere, which can improve the modification effects of Bi in the composites, exhibiting a better electrochemical reversibility.

In this paper, we propose a planar type micro electromagnetic actuator with high force density. The actuator is composed of a mover (8 mm*8 mm*0.5 mm) and a stator (14mm*10mm*0.2 mm). As the mover, a thick NdFeB permanent magnet film (300 μm) with a chessboard pattern (unit size is 0.8 mm*0.8 mm) is attached with a ferromagnetic back yoke to provide enhanced magnetic flux density. In the stator, 3D mesh type micro coil with multi-turn configuration is designed accordingly. The micro coil has a novel connection between adjacent mesh units, which enables easy fabrication. The thick film magnet with chessboard pattern as well as the multi-turn micro coil with novel connection constitute the originality of this actuator. The mover and the stator can be produced by batch fabrication. The magnetic flux density (B) generated by the magnet are simulated and experimentally measured. The magnitude of B at vertical direction attains around 40 m T at 770 μm plane above the surface. Due to delicate design, the MEMS-based micro coil can withstand as high as 0.4A constant current input for over 60 min on a thermal isolated ceramic plate. The long-time duration experiment testifies the practicality of this micro actuator. Both repulsive and attractive electromagnetic force can be generated on the mover by altering the current direction in the stator. The measured force is around 4.3 mN at 20 μm gap with 0.1A stable current input in the stator and the force density attains as high as 0.96 mN/A/mm3.

Converting the carbonaceous solid waste into the battery anode is an attractive approach to retard carbon resource consumption and prevent environmental pollution. Unfortunately, spent carbon cathode (SCC; a hazardous solid waste) after graphitization applied as the anodes of lithium ion batteries delivers the poor performance at high rate. In this work, the rGO-coated SCC treated at 2600 °C (SCC-2600@rGO-Ts) are prepared from SCC-2600 by the self-cycling combined with interface assembly method. The optimized SCC-2600@rGO-800 with the enriched defects, ordered graphene conductive networks, and moderate oxygen-containing functional groups is beneficial to offer many active sites for Li+ storage, ensure a fast electron and ion transfer rate, and improve the wettability between the obtained carbon materials surface and electrolyte. These features are crucial for boosting lithium-ion storage performance, endowing SCC-2600@rGO-800 to deliver a high lithiation capacity of 672.1 mA h g−1 at 0.1 C after 50 cycles and 436.9 mA h g−1 at 1 C retaining 125.9% capacity retention after 500 cycles. Even at 5 C, the capacity of 114.2 mA h g−1 is still obtained after 2500 cycles. Therefore, this work can open up a new approach to recycle and evolve the carbonaceous solid waste to the advanced anodes substitutes for LIBs.

Taking the finite-length sliding bearing as the research object, the Reynolds equation is solved by the finite difference method and the successive over-relaxation iteration method to obtain the oil film pressure. It is concluded that the dimensionless oil film characteristics are related to bearing eccentricity and length diameter ratio. In order to study the oil film characteristics of sliding bearing, the bearing eccentricity and length diameter ratio are taken as the research objects, and the oil film thickness, load component, attitude angle and end discharge flow are solved by numerical analysis. It is concluded that with the increase of eccentricity, the bearing capacity of oil film increases, the attitude angle decreases and the end discharge flow increases with the case of a certain length diameter ratio.

A comparative study on the corrosion resistance of NiFe2O4 ceramic inert anode for aluminum electrolysis prepared in the different sintering atmosphere was carried out in Na3AlF6–Al2O3 melt. The results show that the corrosion rates of NiFe2O4 ceramic inert anodes prepared in the vacuum and the atmosphere with oxygen content of 1×10–2 are 6.08 cm/a and 2.59 cm/a, respectively. A densification layer is formed at the surface of anode due to some reactions which produce aluminates. For the anode prepared in the atmosphere with oxygen content of 1×10–2, the thickness of the densification layer (about 50 μm) is thicker than that (about 20 μm) formed at the surface of anode prepared in the vacuum. The content of NiO and Fe(II) in Ni(II) x Fe(II)1–x Fe(III)2O4 increases with the decrease of the oxygen content of sintering atmosphere, which reduces the corrosion resistance of the material.

An indentation damage test comprises a micro-mechanical tester and an acoustic emission sensor is employed to evaluate the critical force or displacement required to crack the bulk Si die specimen and thin-film stacked specimens. The associated works before and after the indentation damage test are examined from the force-displacement F-d curve. The pseudo-work of indentation damage W d describes the work done by the indenter on the damaged specimen after the crack initiation and propagation, which can be determined by multipling the onset crack force Fc with the ‘pop-in’ or plateau length l obtained from the F-d curve. A simple energy-based approach is then proposed to determine the work of indentation fracture W f based on the difference in the elastic strain recovery between a damaged and a non-damaged specimen during the unloading stage from the onset crack force Fc. It is found that the energy involved in cracking the specimen is much higher than the work done by the indenter at Fc onto those damaged specimens, i.e. Wd

Patients with inadequate volume of alveolar processes or bone defects commonly require graft substitutes in oral, maxillofacial or orthopedic surgery. Ridge augmentation and reconstruction of facial bony defects with bone graft materials achieve better outcomes in functional and aesthetic rehabilitation. The injectable calcium sulfate filler is used widely in intra-operative applications. Calcium sulfate bone filler has been shown to upregulate bone formation-related mRNA genes in vitro and improve osseointegration in vivo. In addition, the bone graft substitute can be used as a drug delivery system for antibiotics to treat or prevent infections based on the clinical experiences. However, the influences of antibiotics addition on the calcium sulfate are not fully understood. In this study, calcium sulfate impregnated with gentamycin in different weight ratios was characterized. The results showed that gentamycin prolonged the hydration process and extended initial/final setting times of calcium sulfate. The addition of gentamycin slowed the conversion from calcium sulfate hemihydrate to dihydrate and changed the crystalline phase and microstructure. Higher amounts of gentamycin added resulted in faster degradation and lower mechanical strength of calcium sulfate. This study reveals that the extended setting time, decreased compressive strength, and the accelerated degradation of the gentamycin-impregnated calcium sulfate bone graft substitutes should be considered during intra-operative applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

A traditional water scrubber is able to remove particles with a size over 200 μm in ship engine exhaust effectively . However, as the size of the particles decreases, the removal efficiency of the particles is gradually reduced, especially when the particle size is less than 50 μm, the method almost has little effect. This paper presents a study charging particles in exhaust gas and water droplets to improve water scrubber’s efficiency in removing fine particles. The efficiency of the method is verified by numerical simulation of Comsol Multiphysics. The numerical simulation results indicates that the removal efficiency of particles in ship exhaust gas can be greatly improved by adding charges to droplets and particles at the same time. And a line chart of particle capture efficiency map under different particle sizes and change of droplets is obtained.

The effects of electrolytic parameters on the content of Sc in Al–Sc master alloy prepared by electrolysis in Na3AlF6-K3AlF6-AlF3 melt were studied. It is observed that the content of Sc in Al–Sc master alloy increases and then decreases with increasing the electrolysis temperature and the cathodic current density. Under the electrolysis condition (temperature 950 °C, cathodic current density 1.50 A cm−2 and concentration of Al2O3 1.0 wt%), the content of Sc in the production is increased from 0.81 to 3.87 wt% as the value of the concentration ratio of Sc2O3 to Al2O3 ([Sc2O3]/[Al2O3]) increased from 2 to 6. The analysis of SEM indicates that the production of Al–Sc master alloy is composed of the aluminum and the Al3Sc. The distribution of Sc in Al–Sc master alloy is uniform.

In this study, the nano-sized ZnO/Bi2O3 composites were synthesized with the zinc-bismuth bimetallic-MOFs as the precursor for the first time. The metal ions were homogeneously anchored on the self-assembled precursor with a structure of hollow sphere. The results showed that the obtained ZnO presented a typical structure of hexagonal prismatic and an even distribution of element Zn and Bi was realized. Utilized as anode materials of Zn/Ni battery, the composites displays an ultra-high average discharge capacity of 630 mAh g−1 at 1 C and longer cycle life than the unmodified pure ZnO.

This paper presents a comparative study of the tribological and vibration performance of the synthesized lithium complex grease (LCG) containing Carbon black, Fe3O4 and Al2O3 nanoparticles on rolling bearing. The micromorphology, friction coefficient, worn surface and bearing vibration experiment of four greases were studied. The results show that in presence of nanoparticles friction and wear behaviors are improved compared to LCG without nanoparticles. The best tribological performance is obtained in presence of Al2O3 nanoparticle, which is mainly attributed to its high hardness, cylindrical shape and deposition on the worn surface. Further, the wettability test shows that Al2O3 nanoparticles can effectively promote the flow of base oil on the LCG soap fibers, which results in the most effective bearing vibration suppression.

Carbon paper (CP) used for proton exchange membrane fuel cells (PEMFCs) are improved using carboxyl-terminated butadiene-acrylonitrile (CTBN)-modified phenolic resin (PF) for impregnation of CP preform. The effect of CTBN ratio on the properties of CP, which is fabricated by the processes of impregnation, molding and heat treatment, is investigated. The results show that compared with the CP without CTBN addition, the CTBN-modified CP exhibits significantly improved overall properties. With the increase of CTBN ratio in the mixture, porosity and permeability of the modified CP increase because of the low carbon yield of CTBN after heat treatment. Mechanical strength and conductivity also increase because of the chemical reactions between the CTBN and resin that lead to robust interfacial bonding in the CP product. However, excessive CTBN addition causes decreased tensile and bending strength of the CP. Single cell tests show that the increased conductivity of the CP enhances the polarization performance in the Ohm polarization region, while the CTBN-induced nearly spherical micro/macro-pores in the CP matrix improve the performance in the concentration polarization region. At an optimum CTBN ratio of 50 wt%, the membrane electrode assemble with the modified CP exhibits a current density of 1606.5 mA cm−2 at 0.608 V.

The safety of lithium ion batteries is a hot topic in battery application and research at present. LiFePO4/C batteries are generally believed to be safe and have been widely used. The LiFePO4/C batteries are taken as the research object, the thermal runaway characteristics of the LiFePO4/C batteries are analyzed from the changes of battery temperature and voltage during the test process. The results show that the battery volatge fluctuated greatly before the thermal runaway occurred for the battery under one side heating, however, the battery voltage did not fluctuate and dropt to 0 V for the battery under two sides heating. For the battery group under one side heating, the thermal runaway chain reaction did not occur, which meant that the LiFePO4/C battery possessed good safety.

Spent carbon cathode (SCC), a hazardous solid waste produced from aluminum reduction, limits the sustainable development of the aluminum industry. This study presents a roasting treatment for removing impurities to achieve the recycling of SCC and the recycled SCC is applied as the anode of Li-ion batteries (LIBs). The effect of the roasting technologies on the carbon content of the SCC was studied, and the results show that the impurities in the SCC can be gradually removed as the temperature increases. The carbon content of the SCC can reach 97.22 % under the optimum parameters, which includ a roasting temperature of 1600 °C, roasting time of 1 h and particle size of 200 mesh. Compared to graphite and SCC, SCC treated at 1600 °C (SCC-1600) as the anodes of Li-ion batteries exhibits a good reversible capacity of 365.5mAh g−1 at 0.1 C after 100 cycles with a decay rate per cycle of 0.028 %. SCC-1600 displays an impressive performance with a reversible capacity of 235.0 mAh g−1 at 1 C after 500 cycles. Recycling SCC as a low-cost material for the anodes of LIBs provides a feasible solution for the efficient disposal of other hazardous carbonaceous solid wastes.

Nanowear behaviors of GeSbTe against SiO2 microsphere were investigated by using an atomic force microscope under atmospheric environment. During the wear tests, the normal load and wear time was set as 5–10 μN and 1–50 s, respectively. The experimental results showed that the normal load and wear time played an important role in the nanowear of GeSbTe. With the increase of the normal load and wear time, the depth of wear scar formed on GeSbTe surface would increase. According to the nanowear tests in pure nitrogen, it was suggested that the nanowear of GeSbTe under atmospheric environment with different loading conditions was dominated by mechanical interactions. Further calculations indicated that the nanowear of GeSbTe under atmospheric environment was caused by the strong shear stress. Meanwhile, the nanowear of GeSbTe would also be affected by the dissipated energy generated in the friction process. Using one single SiO2 tip with different cleanness, it was verified that the wear debris generated during the wear process acted as a lubricant. Consequently, the nanowear of GeSbTe under atmospheric environment was restrained by the wear debris. The results of this study may help us understand the polishing mechanism of GeSbTe during CMP process.

Zn–Ni battery is an attractive aqueous alkaline secondary battery due to its low cost, safety, and environmental friendliness. However, the problems of hydrogen evolution reaction, zinc dendrites growth and deformation of zinc anodes hampering the commercial application of Zn–Ni battery. In this work, the dynamic imbalance behavior of capacity of the Zn–Ni battery which caused by low coulombic efficiency of the anode is studied. Results reveal that due to the hydrogen evolution effect of the anode, the sintered Ni(OH)2 cathode which commonly used in the research of anode of Zn–Ni batteries cannot be fully discharged. Residual capacity will increase the potential of the cathode continuously, shorten the constant current charging time, and cause the battery cycle capacity decay rapidly. This phenomenon is confirmed by adding nano Bi powders to suppresse the hydrogen evolution of the zinc anode. This work reveals that the decline in the cycle life of Zn–Ni batteries is not only due to irreversible changes in the electrode structure but also due to the coulombic efficiency mismatch of the cathode and anode.

The trigger voltage of the HBT device is important for ESD protection. A method of adjusting the trigger voltage of SiGe Heterojunction Bipolar Transistor (HBT) device is proposed in this paper. The simulation and experiment results show that the trigger voltage of HBT can be simply adjusted by varying the emitter junction area.

A wideband high gain and low side-lobe antenna is presented in this paper. The antenna consists of an yagi antenna array and a substrate integrated waveguide (SIW) feeding network. A prototype of the proposed antenna is fabricated and tested, and the simulated and measured results show the good performance of the antenna.

The uniaxial and multiaxial non-proportional cyclic experiments of 16Mn steel under strain-control were carried out using MTS809 machine and Teststar control system. Cyclic softening was observed for 16Mn steel under strain-control cyclic loading. The restraining effects of mean strain, strain amplitude, non-proportional loading path and their histories to subsequent cyclic softening were revealed, and some useful conclusions for establishing constitutive model of non-proportional cyclic were obtained.

Down feather fiber was modified by formamide which acts as a plasticizer and then hot-pressed into thermoplastic down films. After hot-pressed, the mechanical properties of thermoplastic down films had a close relationship with the exposure time periods. The maximum tensile strength of thermoplastic down films can reach 28.74 MPa after exposure to atmosphere for 40 days. ATR-FTIR curves proved that there were hydrogen bonds forming between amino and amide groups of down feather fiber and formamide. WXRD patterns showed that the crystalline region of down feather fiber was destroyed by formamide during hot-pressing and then reformed after exposure to atmosphere for several days. TGA curves showed that thermoplastic down films has lower moisture compared with down feather fiber suggesting that high temperature removed the most of hydrogen-bound water in down feather fiber and then there are chemical reaction between down feather fiber and formamide.

We demonstrate that Young’s modulus of polymerized microstructures in both air and liquid can be controlled by changing the writing velocity of the femtosecond laser two-photon polymerization, which is crucial for many practical applications. For the zirconium/silicon inorganic/organic hybrid sol–gel, the Young’s modulus for dry polymerized micro-cantilevers in air can be adjusted from 5.5 to 9.4 GPa by varying writing velocity from 600 to 200 μm/s, and it also can be controlled in liquid, which is four orders smaller than in air. To characterize the Young’s modulus in liquid, we propose a simple method by measuring non-adhered lengths of the arc-shaped or s-shaped polymerized micro-cantilevers after drying in air.

Using the dry method-prepared polyacrylonitrile based carbon fibers as raw the material, carbon paper applied for proton exchange membrane fuel cells was prepared by the processes of molding, high temperature carbonization, chemical vapor deposition (CVD), and graphitization. The effects of resin carbon content and subsequent heat-treatment process parameters on the properties of carbon paper were studied. The results show that: the resin carbon content is an important factor to affect the density, thickness, through-plane resistivity and porosity of carbon paper. When the resin carbon content is 20%, the thickness of carbon paper is 0.20mm, the density is 0.41g/cm3, and the porosity is 74.5%, in line with requirements of the fuel cell. When the heating time is 4 hours, the porosity is 71.9%.