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Cyclic torsion induced dislocation patterns and evolution process of a single-phase Al 0.1 CoCrFeNi multi-principal element alloy at varying cumulative plastic strain, γ cu , from 0.1 to 14.6, were systematically investigated in this study. The results reveal that conventional single-slip individual dislocations dominate plastic deformation at initial straining stage. Whereas, at larger γ cu up to 1.2, a large number of dislocation locks formed by mutual dislocation interactions in turn induce the extensive proliferation of multi-slip dislocations within the grain interiors. At γ cu > 4, a large number of individual multiple dislocations are gradually organized into massive two-dimensional micrometer-scale multi-slip dislocation wall segments; at γ cu > 8, profuse three-dimensional finer equiaxed low-angle dislocation cells are formed. The distinctive structural characteristics of the sample-level hierarchical dislocation cell structure in metals with low stacking fault energies are mainly caused by the gradient distribution of small but large cumulative plastic strain, which are closely related to the enhanced multiple-slip dislocation activities. [Display omitted] [ABSTRACT FROM AUTHOR]

Ceramic/metal interpenetrating network structure has been proved to have a significant effect on decreasing the coefficient of thermal expansion (CTE) of the metal matrix. In our study, a AgCuTi/SiC interpenetrating network structural composite (ASINC) was fabricated through a melt infiltration method. During the infiltration process, the AgCuTi filler melted and infiltrated into a porous SiC ceramic. Wetting behavior of the AgCuTi on the porous SiC ceramic was studied. Microstructure of the ASINC was characterized. The synthesized ASINC was fabricated as an interlayer to prepare a ZrB 2 –SiC–C ceramic/AgCuTi/ASINC/AgCuTi/GH99 brazed joint. Typical microstructure of the joint brazed at 860 °C for 10 min was investigated. The effect of holding time on the microstructure and the room-temperature shear strength of the brazed joints was studied. The maximum shear strength increased by 161% compared with the case brazed with a single AgCuTi interlayer. Microstructure evolution and mechanical strengthening mechanisms of the brazed joints were discussed in detail. [ABSTRACT FROM AUTHOR]

A novel Ag–Nb 2 O 5 braze filler is developed and successfully tested as a sealant candidate for solid oxide cells. The resultant AgNbO 3 by the reaction between Ag and Nb 2 O 5 at high temperatures turns out to be the key to enable a desirable wetting of the YSZ by the braze filler. Typical interfacial microstructure of the YSZ/AISI 310s brazed joints are characterized by a scanning electron microscopy (SEM) and a transmission electron microscopy (TEM) with an energy dispersive spectroscopy (EDS). Effects of Nb 2 O 5 contents and joining parameters on the microstructural evolution and mechanical performance of the joints are investigated. Joints with a maximum average strength of 100–110 MPa are achieved when bonding at 1150 °C/30 min with 5 mol.% Ag–Nb 2 O 5. The long-term stability of the YSZ/Ag–Nb 2 O 5 /AISI 310s joints are evaluated in air for over 350 h at 800 °C and no cracks or cell degradation are found in the joints after the aging process, indicating that the new-developed Ag–Nb 2 O 5 is a promising candidate as the sealant for the SOFC stacks. [ABSTRACT FROM AUTHOR]

Due to the poor wettability of the AgCuTi alloy on the quartz fiber reinforced composite (QFSC), a reliable joining of the QFSC to itself or to other metals can be hardly achieved. In this study, vertically aligned carbon nanotube (VA-CNT) composed of multi-wall carbon nanotube (MWCNT) was synthesized on the QFSC surface by a plasma enhanced chemical vapor deposition method. As a result, the final contact angle decreased from 96.5° (without VA-CNT modification) down to 30.6° (with VA-CNT modification) at 870 °C with 10min holding duration. Besides, the reaction layers at the AgCuTi/QFSC interface transformed into continuous ones and the infiltration effects became more obvious after the VA-CNT modification. Finally, a possible mechanism how VA-CNT enhanced the wettability of the AgCuTi alloy on the QFSC surface was proposed. Defective sites on the MWCNT surface with a high chemical reactivity and the nanoscale capillary structure of the VA-CNT turned out to be the essential factors to promote the wetting process. This novel surface modification approach can offer new insights on addressing the wetting issues in composites preparation, brazing and soldering, etc.. Image 1098128 [ABSTRACT FROM AUTHOR]

Successful delivery of drugs to the Olfactory region (OR) is the key to treating diseases through the nasal cavity. The purpose of this paper is to investigate the effect of auxiliary airflow on particle deposition in the OR during nasal drug administration. A realistic 3D nasal ensemble model was reconstructed from CT scans of the head of a healthy adult. Computational fluid dynamics (CFD) was used to simulate the effect of auxiliary airflow on the deposition of drug particles in the OR during nasal administration. The discrete phase model (DPM) was adopted to track the deposition trajectories of drug particles. Three auxiliary airflows were selected together with three spray cone angles, four particle sizes, five drug particle delivery velocities and three specific injection positions on the deposition fraction of drug particles in the OR were analyzed. The results indicated that the effect of auxiliary airflow on the deposition fraction of drug particles of different particle sizes in the OR is significant. The delivery efficiency of injection position C is always the greatest. A delivery velocity of 15 m/s is more favorable for nasal administration and the effect of spray cone angle is proportional to the auxiliary airflow. Computational results should be helpful for experimental studies and future nasal optimization. [Display omitted] • The effect of auxiliary airflow on particle deposition is systematically studied. • Drug particles are released at specific locations in the nasal cavity. • The effects of particle parameters are systematically investigated. • Some mechanisms of the effect of auxiliary airflow on deposition are studied. [ABSTRACT FROM AUTHOR]

Abstract Graphene nanosheets (GNSs) had been considered as the potential reinforcements of the composites. In this study, sponge-like graphene was used as a reinforcement to enhance the dispersity of GNSs in the metal matrix. AgCuTi alloy was melted and infiltrated into the sponge-like graphene, which led to the reaction between the GNSs and the AgCuTi alloy. The microstructure on the interface of the GNSs and AgCuTi alloy was characterized. The GNSs reinforced AgCuTi based composite was utilized as an interlayer to braze graphite and Cu, and the dispersity of the GNSs in the brazing seam was discussed. Comparing with the pure AgCuTi interlayer, the shear strength of the graphite and Cu joint was increased by 75% when the GNSs reinforced AgCuTi based composite interlayer was used. Highlights • GNSs reinforced AgCuTi composite was prepared by a melt infiltration method. • The GNSs in the composite were interconnected and free of any agglomeration. • Graphite and Cu were successfully brazed with the addition of the GNSs. • The shear strength was improved by 75% when the interconnected GNSs were added. [ABSTRACT FROM AUTHOR]

Abstract To address the thermal stress issue in the brazed SiO 2f /SiO 2 -Invar joints, a novel nano-TiO 2p (p: particle) modified braze filler was developed. Wetting of the SiO 2f /SiO 2 composite by AgCuTi-based composite braze filler with different TiO 2p contents were conducted first and a TiO 2p content lower than 5 wt% was fixed. Then the microstructure evolution and mechanical performance of the SiO 2f /SiO 2 -Invar joints brazed with different TiO 2p additions and different brazing parameters were discussed. The highest shear strength of 30 ± 8 MPa was obtained at 910 °C/10 min. After using the TiO 2p modified braze filler, the fracture probability of the SiO 2f /SiO 2 -Invar joints dropped down by 75% (Taking 22 MPa as an example). Finally, a FEM was employed to get an in-depth understanding of the stress relief effects when using a TiO 2p modified braze filler. Results show that the compressive stress on the SiO 2f /SiO 2 side dropped down by 30% after using a 2 wt% TiO 2p modified braze filler. The in-situ formed Cu x Ti 6-x O (x = 2, 3) phases played a key role in relieving the residual stress of the brazed joints. The development of the novel TiO 2p modified braze filler was particularly suitable for the joining of the oxide ceramics and oxides-based composites. [ABSTRACT FROM AUTHOR]

Abstract For active brazing, excessive formation of brittle intermetallics in the brazed seam is always a big issue, which has an adverse effect on the joint property. Herein, an innovative vertical few-layer graphene (VFG) buffer layer was directly grown on the Invar surface prior to brazing. SiO 2 -BN ceramic and the Invar alloy with and without the VFG were first brazed using a Ag-Cu-Ti braze alloy. Interfacial microstructure and fracture morphologies of the brazed joints were then put into comparison. Results show that there is a 20% increase in shear strength after the VFG modification. To further discuss the effect of the interfacial microstructure variation on the joint property, Invar alloy was self-brazed. The fracture path and the tensile-shear strength of the Invar/Invar joints were discussed. Finally, the interaction between the VFG and Ti was characterized and the controlling mechanism of the intermetallic compounds formation by the VFG was proposed. This novel surface modification approach reported in this paper was promising particularly for the active brazing associated with the brittle IMCs formation issue. [ABSTRACT FROM AUTHOR]

Abstract In this study, the SiBCN ceramic and TC4 alloy were successfully brazed using TiB 2 reinforced AgTi composite filler in a vacuum furnace. The typical interfacial microstructure of the joint and the reaction products were identified through EDS, SEM and XRD. The effect of the TiB 2 content and brazing temperature on the joint microstructure and property were investigated. During the brazing process, the filler reacted with the SiBCN to form TiC + TiB + TiN + Ti 5 Si 3 reaction layer adjacent to the SiBCN. With the increase of the TiB 2 content in the composite filler, the diffusion of Ti in the brazing seam was restrained, and the reaction layer became thinner. Meanwhile, the TiB 2 volume fraction in the brazing seam increased. The increase of the brazing temperature promoted the reaction of the braze filler and the base materials. Thick reaction layer adjacent to the SiBCN and lots of Ti (s.s) and Ti 2 Ag in the brazing seam were obtained at high brazing temperature. When the SiBCN and TC4 were brazed using 6 wt% TiB 2 reinforced AgTi composite filler at 980 °C for 10 min, the maximum shear strength of the joint reached 32 MPa. Highlights • The SiBCN and TC4 were vacuum brazed using TiB 2 reinforced AgTi composite filler. • The typical microstructure of the SiBCN/TC4 joint was investigated. • Both of the TiB 2 content and brazing temperature affects the microstructure and property of the joint significantly. • The maximum strength of the joint reached 32 MPa when the joint brazed using AgTi-6TiB 2 at 980 °C for 10 min. [ABSTRACT FROM AUTHOR]

Abstract Carbon fiber reinforced carbon matrix (C f /C) composite and Ni base superalloy were brazed in vacuum using MBF 20 filler. By varying brazing temperatures and holding times, the effects of brazing parameters on the microstructure as well as its evolution and mechanical properties of the joints were investigated. The results show that the microstructural evolution of joints experiences three stages. With the rising of brazing process parameters, the dissolution of C f /C turns strong, leading to the formation of rough composite/filler interface and the increasing of amount of Cr 7 C 3 and MC complex metal carbides. The residual stress concentration in joint changes consequently. The maximum shear strength of the joint can reach 35 MPa (which is up to 92% of the shear strength of C f /C substrate), 15 MPa and 9 MPa at room temperature, 800 °C and 1000 °C, respectively. The fracture initiates and propagates in C f /C composite. Highlights • C f /C composite and GH99 superalloy were successfully brazed using MBF 20 filler in vacuum. • The microstructural evolution experiences three stages: the substrates dissolving and elements diffusing; the carbides forming; the carbides layer forming and growing. • With the rising of brazing parameters, the interfacial reaction is promoted and carbides grow into a continuous layer adjacent to C f /C. • The maximum shear strength of the joint reaches 35 MPa at room temperature, 15 MPa at 800 °C and 9 MPa at 1000 °C. [ABSTRACT FROM AUTHOR]

For the active brazing of ceramic/metal couples, formation of brittle intermetallics in the brazed seam is often a big issue that needs to be addressed. Herein, a novel vertical few-layer graphene (VFG) modified Cu-23Ti braze filler was developed to join the SiO 2f /SiO 2 composite and the Invar alloy. Microstructures of the wetting interfaces and the SiO 2f /SiO 2 -Cu23Ti-Invar brazed joints with and without the VFG modification were put into comparison. Results show that the formation of intermetallics in the brazed seam are greatly suppressed and the joint strength improves by 2 times after using a VFG-modified Cu-23Ti braze filler. Typical microstructure of the SiO 2f /SiO 2 -Invar joint brazed using a VFG-modified Cu-23Ti braze filler was characterized and the joint formation mechanism was proposed finally. [ABSTRACT FROM AUTHOR]

In order to improve the ZrC-SiC and TC4 brazed joint property, functionally graded material (FGM) layers (two SiC particles reinforced TC4-based composite layers) were designed to relieve the residual stress in the ZrC-SiC and TC4 brazed joint. The FGM layers were fabricated on the TC4 surface using laser additive manufacturing technology before the brazing. Then the TC4 coated with the FGM layers and ZrC-SiC ceramic were brazed using Ti-15Cu-15Ni (wt%) filler. According to the SEM and TEM results, the volume fractions of SiC particles in the FGM layers could reach 20% and 39% respectively. Ti from the braze filler and TC4 reacted with the ZrC-SiC ceramic to form TiC and Ti 5 Si 3 adjacent to the ZrC-SiC ceramic. The shear test results indicate that the adoption of the FGM layers and the brazing temperature both affected the joint property significantly. The FGM layers could benefit the mitigation of coefficient of thermal expansion (CTE) mismatch between the ZrC-SiC and TC4, so that the residual stress caused by the CTE mismatch in the joint was relieved and the joint strength increased. The brazing temperature would affect the microstructure of the brazing seam and then control the joint strength. When the ZrC-SiC ceramic and TC4 coated with the FGM layers were brazed at 970 °C for 10 min, the maximum shear strength could reach 91 MPa, and cracks propagated in the ZrC-SiC ceramic substrate during the shear test. [ABSTRACT FROM AUTHOR]

Although endowed with abundant tidal resources, China's tidal power generation industry has been largely lagging behind other renewable energy alternatives such as small hydropower, photovoltaic power, wind power and biomass-based power. To probe the reasons behind this slow pace of development, an emergy evaluation and an economic analysis were conducted on the Jiangxia Tidal Power Station (JTPS), which has an installed capacity of 4.1 MW. The JTPS is the largest tidal power station in China and the fourth largest in the world. The evaluation results exhibited a total power conversion system emergy use of 1.59E+19 sej to generate 5.90E+13 J of electricity in 2014. Tidal energy only accounts for 16.54% of the total energy budget. The rest of the resources were invested to capture and convert tidal energy to electricity, thereby generating a relatively low efficiency or high transformity of 2.69E+05 sej/J. The results revealed a JTPS emergy loading ratio (ELR) and energy sustainability index (ESI) of 3.72 and 0.41, respectively, which indicates poorer environmental performance compared to other renewable energy power plants, with the exception of photovoltaic power. In addition, the economic analysis revealed a JTPS power generation cost of 2.41 CNY/kWh, which is even higher than that of concentrating solar power (CSP). The JTPS is less competitive because tidal energy has a lower quality and is more decentralized when generating electricity compared to other renewable resources. This inefficiency was exacerbated in the JTPS case due to the original multipurpose design and consequential poor site selection with respect to tidal electricity generation. These results further highlight the importance of dam site selection and the tidal range, as they are critical for the improvement of the tidal power generation environmental performance. More importantly, R&D is essential to promote the development of this technology and to ultimately utilize abundant tidal resources in an efficient and sustainable way. [ABSTRACT FROM AUTHOR]

An AgCu-4.5 wt.%Ti/W/AgCu-1 wt.%Ti composite interlayer was designed to braze the Invar-SiO 2f /SiO 2 joints. Ti contents in the interlayer between the tungsten foil and the Invar alloy was optimized. The effects of the tungsten-foil thickness on the microstructure, elemental distribution and mechanical properties of the brazed joints were investigated. Compared with a single AgCu-4.5 wt.%Ti interlayer, a sufficient metallurgical reaction happened on the SiO 2f /SiO 2 composite side and the formation of Fe 2 Ti, Ni 3 Ti compounds which are detrimental to the joint properties, was greatly inhibited by using a low-expansion composite interlayer (LECI). The tungsten interlayer can reduce the CTE (coefficient of thermal expansion) mismatch in the Invar-SiO 2f /SiO 2 joint. The highest shear strength of joints brazed with an LECI was 33 MPa, which was 1.75 times higher than the joints brazed with a single AgCu-4.5 wt.%Ti interlayer. [ABSTRACT FROM AUTHOR]

In this study, transparent alumina and TiAl alloy were successfully brazed at 860°C-940 °C using Ag-21Cu-4.5Ti (wt%) filler metal. The microstructure and mechanical properties of the joints were investigated. SEM and TEM analysis showed the typical interfacial microstructure of the joints brazed at 900 °C for 5min was TiAl/β-Ti + AlCuTi/AlCu 2 Ti + AlCuTi/AlCu 2 Ti + Ag(s,s) + Cu(s,s)/(Cu,Al) 3 Ti 3 O/transparent alumina. The effects of brazing temperature and holding time on the microstructure and mechanical properties of TiAl/transparent alumina joint were studied. In addition, the effects of the dissolution and diffusion of TiAl on the microstructural evolution of the brazing seam were discussed. Shear strength analysis reveals that the shear strength of the joint increases at first and then decreases when brazing temperature rises. The maximum shear strength is 49 MPa when the joint is brazed at 900 °C for 5 min. [ABSTRACT FROM AUTHOR]

ZrC-SiC ceramic and TC4 alloy were successfully brazed using a self-prepared Ti-15Cu-15Ni filler. The microstructure and mechanical property of the joints obtained at different brazing temperatures were investigated. The results indicated that Ti from the Ti-15Cu-15Ni and the TC4 reacted with the ZrC-SiC to form TiC phase adjacent to the ZrC-SiC ceramic. In the brazing seam, Ti 2 (Ni, Cu) intermetallic compounds zone (IMCs Zone), Hypoeutectic Zone and Hypereutectoid Zone formed. The brazing temperature affected the dissolution of TC4 into the braze filler significantly, and then determined the microstructure of the joint. The formation of α-Ti in the brazing seam could decrease the hardness and the brittleness of the brazing seam, which was beneficial to the property of the brazed joint. The joint strength reached a maximum value of 43 MPa when the joint was brazed at 970 °C and cracks propagated in the ZrC-SiC substrate near the brazing seam. [ABSTRACT FROM AUTHOR]

The multilayer Ti and Ni foils were designed to braze SiO 2 -BN diphase ceramic with Nb at 1140 °C for 5min. The interfacial microstructure was examined using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM) and X-ray diffraction (XRD) methods, respectively. Experimental results and thermodynamical calculations showed that the interfacial microstructures between Nb and SiO 2 -BN ceramic were (βTi,Nb)-TiNi eutectic structure/TiNi + TiNi 3 /TiN + Ti 3 O 5 + TiB 2 + Ti 5 Si 3 . The effects of the Ti content in the Ti-Ni braze alloy on the microstructures of the joints were investigated. With the increase of the Ti content, less Ni 3 Nb formed in the joint and TiNi 3 phase successfully turned into TiNi and Ti 2 Ni. The effects of the Ti content in the Ti-Ni braze alloy on the shear strength of the joints showed that the optimum thickness of the TiN + Ti 3 O 5 + TiB 2 + Ti 5 Si 3 reaction area was about 13 μm and the maximum shear strength of 52 MPa was achieved when the Ti content was 45 wt.%. [ABSTRACT FROM AUTHOR]

A novel composite interlayer with a reinforced network was designed using a SiC ceramic with a network structure and Ti-Ni-Nb composite filler foils, to which the Nb and BN-SiO 2 ceramic were successfully brazed under vacuum. For a brazing temperature of 1160 °C and holding time of 10 min, the interfacial microstructure of the Nb/BN-SiO 2 ceramic joint was Nb/(βTi,Nb)-TiNi eutectic structure+(βTi,Nb) 2 Ni+SiC+TiC/TiN+Ti 2 N+TiB+Ti 5 Si 3 +TiO/BN-SiO 2 ceramic. In addition, the shear strength and nano-hardness were analyzed to evaluate the effect of the composite interlayer with a network reinforcement architecture on the mechanical properties of the joint. During brazing, the Ti-Ni-Nb filler metal infiltrated and reacted with the SiC to form the network reinforcement architecture, resulting in the residual stress being relieved and the mechanical performance of the joint being significantly improved. A maximum shear strength of 102 MPa was achieved, which was 60 MPa (142%) higher than that of the joint brazed without the network reinforcement architecture. A reduction in the residual stress on the BN-SiO 2 ceramic side from 328 MPa to 210 MPa was observed with the network reinforcement architecture, and the fracture path of the joint changed from the surface of the BN-SiO 2 ceramic to the interfacial reaction zone. [ABSTRACT FROM AUTHOR]

Emergy analysis can facilitate unified system resources accounting. By combining emergy method with input–output modeling technology, this paper developed an eco-thermodynamic input–output model of the 2007 China economy to account for the sector-specific resource intensities. The results show that the resource intensities for Chinese industry sectors present a distribution with a certain pattern which may vary over three orders of magnitude, measured in terms of resource consumption against economic capital generation. At the scale of the entire economy, the emergy intensities for the resource extraction sectors of non-metallic minerals and metallic ores are the highest. Sectors with the smallest emergy to money ratios are service sectors which rely less on primary natural resources. The sector of coal mining is found to have the largest resource intensity of 6.19E+16 seJ/1E+4 CNY among all sectors, while the sectoral intensity of scrap and waste is only 6.44E+14 seJ/1E+4 CNY, the least one. The insight obtained by juxtaposing resource intensities as well as their structures of industry sectors is useful to identify opportunities for reducing resource intensities that could enable improvements in their ecological sustainability. [ABSTRACT FROM AUTHOR]

The SiO 2f /SiO 2 composite and the Invar alloy were brazed at 860 °C from 5 min to 25 min using an AgCuTi alloy. Scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer (EDS) was employed to examine the elemental distribution in the joint. X-ray diffraction (XRD) and transmission electron microscopy (TEM) was selected to accurately identify the species, morphologies and crystal structures of the reaction products. The effect of the holding time on the interfacial microstructure evolution of the joint was studied in detail. The shear strength of the joints and the fracture morphologies were closely related to the thickness of the whole reaction layer, as well as the thickness ratio of the Ti 5 Si 3 + TiO 2 layer to the Cu x Ti 6-x O layer. The maximum shear strength was 26 MPa obtained at 860 °C for 10 min. Finally, the formation of the reaction products in the joint was analyzed by thermodynamic calculations. A brazing mechanism was proposed based on the experimental results. [ABSTRACT FROM AUTHOR]

In this paper, vertical graphene nanosheets (VGNs) were grown by PECVD method. Based on SEM, TEM, Raman and XPS spectrum analysis, the defect-guided growth mechanism of the VGNs was proposed. The effects of defects on the formation of VGNs were discussed in detail. In addition, different densities of defects were produced on the grown VGNs by adjusting different Ar ion sputtering durations. Contact angles (CA) were measured to illustrate the effect of the density of the defects on the wettability of the VGNs. The CA decreases from 102.9° (without sputtering) to 91.5°, 75.1° and 47.8° respectively as the density of the defects increases. It confirms that the wettability of the VGNs could be controlled from hydrophobic to hydrophilic nature by introducing defects. [ABSTRACT FROM AUTHOR]

A kind of novel composite filler was designed using FeCoNiCrCu high entropy alloy and pure Ti foil. ZrB 2 SiC C ceramic and GH99 superalloy were brazed with the composite filler. The interfacial microstructure as well as brazing mechanism was investigated. The mechanical properties were also assessed. The results show that the high entropy mixing effect of the Ti/FeCoNiCrCu composite filler keeps the activity of Ti and Cr. The solid solution forms as the matrix of brazing seam. The phase structure of (TiB + Cr B)/solid solution promise a good bond between ZSC and GH99. The interfacial reaction is affected greatly by the brazing parameters, because the activity of Ti and Cr is changed. The maximum shear strength reaches 71 MPa when the joint is brazed at 1180 °C for 60 min. Cracks primarily propagate in the ZSC away from the reaction zone. [ABSTRACT FROM AUTHOR]

Transient liquid bonding (TLP) of IC10 single crystal with GH3039 alloy was carried out using BNi2 interlayer. Microstructure evolution and mechanical properties of the joints bonded at 1050–1200 °C for 2 h were investigated. The precipitates in the DZ on the GH3039 side gradually decreased and disappeared with the increase of the bonding temperature. The formation mechanism of the TLP joint was proposed and the asymmetry of the bonding was discussed. Tensile strength and microhardness tests were conducted to investigate the mechanical properties of the joints. The layer of borides with high hardness in the joint bonded at 1150 °C significantly reduced the room-temperature tensile strength but had little effect on the high-temperature tensile strength of the joint. The layer of borides became the preferential position to crack during both room-temperature and high-temperature tensile tests. The joints with dispersive precipitates had the highest room-temperature tensile strength and the homogenized joints showed the best ductility. [ABSTRACT FROM AUTHOR]

Starting with the 11th Five-Year Plan (FYP) and continuing in the 12th FYP, quantitative and binding targets have been set for energy-efficiency improvement in China. Drawing on international experience in burden-sharing on climate change, this paper presents a framework for provincial-level disaggregation of energy-saving targets in China. Based on principles of equity and efficiency, four scenarios have been established by weighting different choice preferences of responsibility, capacity, and potential. In addition, nonlinear and linear allocation models have been developed by considering or ignoring marginal energy-saving cost. When this framework was applied to the disaggregation of the national energy saving target of 16% during the 12th FYP, the results show that the final allocation schemes are largely determined by the policy maker's choice preferences. The extreme reduction target of 37.26% fell to Shanghai under responsibility preferring (RP) using the linear allocation method, while the capability preferring (CP) scenario considering marginal energy-saving cost is the closest to the actual scheme accepted by the 30 provinces. Development of such a framework may serve as a feasible policy instrument to help China achieve its conservation targets in a cost-effective way and in accordance with its regional development strategies. [ABSTRACT FROM AUTHOR]

Abstract: Carbon emissions due to rural energy consumption in China have not yet been sufficiently addressed or quantified. In this work systematic accounting with a life cycle perspective was used to estimate both the direct CO2 emissions from fuel combustion and the indirect emissions from the production and provision of rural energy carriers. The results indicate that the total direct CO2 emissions resulting from rural energy consumption have nearly tripled, from 0.79 billion metric tons (hereafter ton) in 1979 to 1.98 billion tons in 2008, whilst indirect emissions have nearly quadrupled, from 0.27 billion tons to 0.85 billion tons for the same period. This finding quantitatively illustrates the importance of rural energy consumption as a contributor to China's overall carbon emission. In addition, the analysis of per capita emission from rural energy revealed significant regional disparities and similarities in emission and energy sources used. Both total and per capita CO2 are significantly higher in the North China, which is largely due to the colder climate and the relatively high economic development levels for multi-demands of energy utilisation. The analysis and results presented here provide substantial information for policy makers in relation to energy and emission targets in China. [Copyright &y& Elsevier]

Highlights: [•] Effects of oxygen on the growth of CNTs using PECVD have been studied. [•] The OH radical has strong etching effect on CNTs. [•] The OH radical can efficiently purify CNTs and improve the activity of catalyst. [•] This study will be useful in the synthesis of high-quality aligned CNTs. [ABSTRACT FROM AUTHOR]

Abstract: Ag–Cu/Cu/Ag–Cu–Ti composite interlayer was successfully designed to braze Invar alloy and SiO2–BN ceramic. The effect of Cu-foil thickness on the microstructure and mechanical properties of the brazed joints was investigated. The results showed that, compared with single Ag–Cu–Ti brazing foil, the formation of brittle Fe2Ti and Ni3Ti compounds detrimental to the joint strength was greatly inhibited by using composite interlayer. The active Ti atoms in the liquid filler reacted with SiO2–BN ceramic to form a TiN–TiB2 fine-grain layer. The desired interfacial microstructure composed of layered Ag- and Cu-based solid solutions was obtained, which was beneficial for the joint strength. The shear strength of brazed joints was 207% higher than the joints brazed with single Ag–Cu–Ti foil when a 100μm thick Cu interlayer was used. The inhibition of brittle compounds formation was attributed to the control of reaction sequences during brazing and to the addition of Cu barrier layer. [Copyright &y& Elsevier]

Abstract: Given the rising expectations for the substitution of fossil energy with renewable energy as one of the solutions to cope with climate change, the carbon emission reduction potential of possible solutions should be evaluated in a holistic and systematic way. In this paper, a systematic account of carbon emission reduction potential was conducted for a typical household biogas system with a digester volume of 8 m3, using a hybrid life-cycle assessment method. Using a 20 year operation scenario, the total life cycle CO2 emission of this family-size biogas utilization system is 2.60 tons, i.e., 0.02 kg CO2/MJ, of which 98.46% is attributed to indirect emissions from building materials and labor inputs. Considering the carbon emission savings due to energy and fertilizer substitution, the annual CO2 emission reduction potential is 1.25 tons for the biogas system that is under consideration. Consequently, such rural household biogas systems should be operated for at least 1.78 years to achieve a positive reduction benefit, i.e., cumulative CO2 emission savings could offset the life-cycle-related CO2 emissions. The results also indicate that long-term, stable running and maintenance are key points to maximize the benefits of household biogas as an effective approach for carbon emission abatement in the rural areas of China. [Copyright &y& Elsevier]

Abstract: Ag–Cu–Ti+BN composite filler was developed to braze SiO2-BN ceramic and titanium. The effects of BN particles content on the microstructure and mechanical properties of the joints were investigated. The fine TiB whiskers and TiN particles were synthesized in the brazing seam by introducing BN particles. TiN–TiB2 reaction layer formed adjacent to SiO2-BN ceramic while Ti–Cu compound layer formed at Ti substrate. With the increase of BN content, more fine-grains formed in the joint and the reaction layer nearby the base materials became thinner. The hardness and modulus of the reaction phases were characterized by nanoindentations to reveal the plastic deformability of the brazing seam. The improvement of the joint strength was 340% with 3wt.% BN addition. The joint strength was determined by the thermal expansion mismatch between the joined materials, plastic deformation in the brazing seam, and interfacial structure of the joint. [Copyright &y& Elsevier]

Abstract: The crystallization behavior and hydrogen storage kinetics of the amorphous Mg11Y2Ni2 alloy prepared by melt-spinning technique were investigated in detail. It was found that the amorphous Mg11Y2Ni2 alloy transforms into the crystalline Mg11Y2Ni2 in metastable state at 279°C and subsequently decomposes into Mg, YMgNi4 and Y(Mg) solid solution in stable state at 366°C. All the amorphous, metastable and stable Mg11Y2Ni2 alloys can be hydrogenated into MgH2, Mg2NiH4 and YH2/YH3. However, the stable Mg11Y2Ni2 alloy has slightly slower hydrogen absorption–desorption kinetics due to the worse dispersivity of YH2/YH3 and Mg2NiH4. [Copyright &y& Elsevier]

Abstract: SiO2BN ceramic surface modified by electron-beam evaporated Ti was brazed to itself using an inactive AgCu eutectic alloy at 840°C for 10min. The effect of Ti content on the microstructure and mechanical properties of the joints was investigated by scanning and transmission electron microscopy and shear test. The results showed that the evaporated Ti layer dissolved into the liquid AgCu alloy rapidly and reacted with SiO2BN ceramic to form a TiNTiB2 fine-grain layer. AgCu eutectic structure in the center of the joint was gradually taken place by TiCu compounds with the increase of the Ti content. This microstructure evolution remarkably affected the shear strength of the joint. The highest shear strength of 39.2MPa was obtained when the Ti content in the brazing alloy was 2.0wt%. The joint strength was clearly improved when a soft Cu interlayer was inserted between two AgCu brazing foils. The effect of Cu-foil thickness on the microstructure and the shear strength of the joint was studied. [Copyright &y& Elsevier]

Abstract: The active brazing of Invar to SiO2–BN ceramic was performed using an Ag–Cu/Ti filler metal. The effects of brazing temperature and Ti content on the microstructure and mechanical properties of Invar/SiO2–BN brazed joints were investigated. The results indicated that the typical microstructure of the joint was Invar alloy/small Fe2Ti+Ni3Ti blocks/Ag(s.s)+Cu(s.s)/wave-like Fe2Ti+Ni3Ti structure/Ag–Cu eutectic/TiN+TiB2 reaction layer/SiO2–BN. The amount of brittle Fe2Ti+Ni3Ti compounds increased and the TiN+TiB2 reaction layer became thick with the increase of brazing temperature as well as Ti content. This microstructure evolution clearly affected the shear strength of the joint. The highest shear strength was obtained when the joint was brazed at 880°C for 10min, with a Ti content of 4.5wt%. When a Cu barrier foil was inserted between the Ag–Cu and Ag–Cu–Ti brazing foils, the formation of brittle Fe2Ti+Ni3Ti compounds was apparently inhibited, and the shear strength of the joint increased correspondingly. [Copyright &y& Elsevier]

Abstract: The Chinese government has increasingly turned to agricultural industry policy as a means of promoting rural development, which have not necessarily led to an improvement in rural incomes nor to the achievement of other social and environmental goals. Emergy synthesis methods were applied to four agricultural production systems, i.e., two local traditional production systems as maize plantation and pond fish farming, one scaled Shaoxing duck (Anas Platyrhyncha var. domestica) rearing system, and one newly introduced specialty production system of common mushroom (Agaricus Bisporus) cultivation, in Weishan county of Shandong province of China in the year 2007, to assess and compare their environmental performances. Additionally, aiming at understanding the benefits and driving forces of agricultural diversification, environmental performance results were contrasted with traditional economic indicators. As indicated by EYR, ELR and ESI, it can be clearly shown that the scaled duck rearing and newly introduced common mushroom cultivation alternatives are not in a sustainable pattern, although having better economic performance than maize cropping and pond fish farming. Nevertheless, the development of rural agricultural diversification is also affected by land accessibility, investment ability and even labor availability. Therefore, achieving a profitable and environmental sustainable diversified farming system is not an easy task in Weishan area as well as in whole China. It is unwise to encourage development of agricultural diversification in current manners without too much consideration on environmental degradation. [Copyright &y& Elsevier]

Abstract: SiO2-BN ceramics and Invar alloy were jointed by active brazing using Ag–21Cu–4.5Ti (wt.%) filler at 1113–1173K for 5–30min. Scanning and transmission electron microscopy studies revealed that the amorphous SiO2 was not reacted during brazing while h-BN had strong tendency to react with Ti to formation a fine-grain layer adjacent to SiO2-BN ceramic. The composite TiN–TiB2 fine-grain layer with the thickness of 100–150nm was the key factor in achieving a good bond between SiO2-BN ceramic and Invar. Invar alloy dissolved into the molten filler and reacted with Ti to form Fe2Ti and Ni3Ti, which dispersed in Ag- and Cu-based solid solution. The shear strength of the joint decreases with the increase of Fe2Ti and Ni3Ti brittle compounds. The maximum shear strength reached 32MPa when the joint brazed at 1153K for 10min. Cracks primarily propagated in the SiO2-BN ceramic and partially along the reaction layer. [Copyright &y& Elsevier]

Abstract: In situ formed TiB whisker-reinforced TiAl and C/SiC joints, containing 30% of TiB whiskers by volume, were produced by vacuum brazing with (Ti–66Ni)1−x B x (x =3wt.%) alloy at 1160°C for 10min. The brazing alloy prepared by arc-melting was mainly comprised of TiNi3 and TiNi eutectic microstructure, in which some black TiB2 blocks formed. TiB2 was transformed into TiB whiskers during brazing due to the successive dissolution of TiAl substrate. The interfacial structure of the brazed joint consisted of β reaction layer transformed from TiAl, TiB whisker-reinforced central zone and TiC reaction layer adjacent to C/SiC. The in situ formed TiB whiskers were beneficial in reducing the joint residual stresses and reinforcing the joint. The average shear strength reached 90MPa and 65MPa at room temperature and 600°C, respectively. Fracture primarily propagated in the SiC matrix with the carbon fiber being pulled out. Contributing factors to the high strength included the possibility of the pull-out of carbon fibers, the diversion of crack propagation direction and the “nail effect” which formed by the infiltration of the brazing alloy. [Copyright &y& Elsevier]

Emergy and economic methods were used to evaluate and compare three fish production models, i.e., cage fish farming system, pond intensive fish rearing system and semi-natural extensive pond fish rearing system, in Nansi Lake area in China in the year 2007. The goal of this study was to understand the benefits and driving forces of selected fish production models from ecological and economic points of view. The study considered input structure, production efficiency, environmental impacts, economic viability and sustainability. Results show that the main difference among the three production systems was the emergy cost for fish feed associated with their feeding system, i.e., feeding on natural biomass such as plankton and grass or on commercial feedstock. As indicated by EYR, ELR and ESI, it can be clearly shown that the intensive production model with commercial feed is not a sustainable pattern. However, the point is that more environmentally sound patterns do not seem able to provide a competitive net profit in the short run. The intensive pond fish farming system had a net profit of 2.57E+03 $/ha, much higher than 1.27E+03 $/ha for cage fish farming system and slightly higher than 2.37E+03 $/ha for semi-natural fish farming system. With regard to the drivers of local farmer’s decisions, the accessibility of land for the required use and investment ability determine the farmer’s choice of the production model and the scale of operation, while other factors seem to have little effect. Theoretically, the development of environmentally sustainable production patterns, namely water and land conservation measures, greener feed as well as low waste systems is urgently needed, to keep production activities within the carrying capacity of ecosystems. Coupled emergy and economic analyses can provide better insight into the environmental and economic benefits of fish production systems and help solve the problems encountered during policy making. [Copyright &y& Elsevier]

Abstract: Let be Hermitian whose entries on and above the diagonal are independent complex random variables satisfying the Lindeberg type condition. Let be nonnegative definitive and be independent of . Assume that almost surely, as , the empirical distribution of the eigenvalues of converges weakly to a non-random probability distribution. Let . Then with the aid of the Stieltjes transforms, we show that almost surely, as , the empirical distribution of the eigenvalues of also converges weakly to a non-random probability distribution, a system of two equations determining the Stieltjes transform of the limiting distribution. Important analytic properties of this limiting spectral distribution are then derived by means of those equations. It is shown that the limiting spectral distribution is continuously differentiable everywhere on the real line except only at the origin and that a necessary and sufficient condition is available for determining its support. At the end, the density function of the limiting spectral distribution is calculated for two important cases of , when is a sample covariance matrix and when is the inverse of a sample covariance matrix. [Copyright &y& Elsevier]

Abstract: In this paper, SiO2 glass ceramic was brazed to Ti–6Al–4V alloy with a commercially available AgCuTi filler foil as braze alloy. Various brazing heating cycles were carried out to study the effects of brazing parameters on the joint interface and mechanical properties. The experimental result shows that the typical interface structure of the joints is SiO2/TiSi2 +Ti4O7/TiCu+Cu2Ti4O/Ag(s.s)+Cu(s.s)/TiCu/Ti2Cu/Ti+Ti2Cu/Ti–6Al–4V from SiO2 glass ceramic to Ti–6Al–4V alloy side. The microstructure of the brazed joint is related to the solution and chemical reaction among atoms during the brazing. According to the mechanical property tests, the joint brazed at 900°C for 5min obtains the maximum shear strength 27MPa. [Copyright &y& Elsevier]

Abstract: In this study, a commercially available Ag–Cu–Ti braze alloy foil was used to join SiO2 glass ceramic and 30Cr3 high-tensile steel. According to experimental observations, the interface structure can be expressed as SiO2 glass ceramic/TiSi2 +Ti4O7/Ti2Cu+Cu3Ti3O/Ag(s.s)+Cu(s.s)/TiFe2/30Cr3 high-tensile from SiO2 glass ceramic side to 30Cr3 high-tensile steel side. With the increased brazing temperature, the thickness of Ti2Cu+Cu3Ti3O layer increases at first and then reduces. The thickness of TiSi2 +Ti4O7 layer and that of TiFe2 layer rise with the increased brazing temperature. According to experimental results of the mechanical properties, the maximum shear strength is 37MPa when the joint was brazed at 900°C for 5min. [Copyright &y& Elsevier]

Abstract: Carbon black (CB) was mixed with fusion-bonded epoxy (FBE) coatings to generate a series of formulations with 0.5–4% by weight of carbon black. The degradation of these FBE coatings on mild steel exposed to a quiescent 3% NaCl solution was monitored using electrochemical impedance spectroscopy (EIS). The experimental results showed that the electrochemical behaviour of coated systems changed dramatically when the CB concentration reached 3% by weight. This phenomenon was relevant to the formation of the percolation regime in the coating, at which a sharp drop in the electrical resistance of the coating was achieved by the generation of a continuous conducting network. A comparison of the protective properties of the FBE coatings filled with various CB loadings, along with the inspection of view underneath the coatings, indicated that the protective performance of the FBE coating was significantly improved when the CB loading exceeded the threshold concentration. This conclusion was confirmed by the results obtained from Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) measurements. [Copyright &y& Elsevier]

Abstract: Compared with the slow response of temperature-driven shape-memory and bulky magnetic-driven shape-memory systems, electric-driven shape-memory has the advantage of “quick and slim actuation”. Electric-driven shape-memory by conventional converse piezoelectric effect is restricted by the small effect. In the present paper we show that by utilizing a defect-mediated reversible domain switching mechanism, it is possible to achieve a large electro-shape-memory effect in ferroelectric martensite system, which is over one order of magnitude larger than conventional converse piezoelectric effect. Direct evidence for the reversible domain switching process is obtained by in situ domain observation. Furthermore, similar effect is also found in ferroelectric polycrystals/ceramics, which shows good stability over a wide frequency range and high reliability against field cycling. The new electro-shape-memory effect may have promising application potential in nonlinear actuators. [Copyright &y& Elsevier]

Abstract: Very recently a giant electric-field-induced recoverable shape change effect (electro-shape-memory effect) has been found in aged BaTiO3-based ferroelectric crystals. This effect is supposed to come from a reversible domain-switching process with the restoring force provided by a symmetry-conforming principle of defects. However, the reversible domain switching process itself behind the giant electro-shape-memory effect is yet to be directly verified. In the present study, we performed in situ domain observation during electric field cycling for aged Mn-doped BaTiO3 single crystals and simultaneously measured its macroscopic properties. It was found that the aged sample shows a reversible domain switching during electric field cycling; this corresponds very well to the electro-shape-memory effect (with a maximum shape change of 0.4%, which is almost half of the theoretical value). This provides a direct mesoscopic evidence for the defect-mediated reversible domain switching mechanism. Moreover, as all these effects stems from aging in ferroelectric state, we further explained that their microscopic origin is symmetry-conforming property of defects, which is completed during aging by defect migration. [Copyright &y& Elsevier]

Abstract: This study investigates the influences of brazing temperature and time on mechanical properties of TiC cermet/Ag–54Cu–33Zn/steel joint. Test result shows that interface products of the brazed joint are, respectively (Cu, Ni), Ag (s.s)+Cu (s.s), (Cu, Ni), (Cu, Ni)+(Fe, Ni) from TiC cermet to steel side. When the brazing temperature is low or time is short, the joint belongs to cleavage and quasi-cleavage fracture and the fracture site is on the interface of (Cu, Ni)/Ag (s.s)+Cu (s.s). When the brazing temperature and time are increased to 850°C and 15min, the joint achieves the maximum shear strength 95.7MPa, which is tough and cleavage fracture and the major fracture site is in Ag (s.s)+Cu (s.s) zone. Furthermore, when the brazing temperature or time continues to be increased, the joint belongs to cleavage and quasi-cleavage fracture and the joint cracks in (Cu, Ni)+(Fe, Ni) zone or (Cu, Ni) zone. [Copyright &y& Elsevier]

Abstract: The degradation of three different fusion-bonded epoxy (FBE) powder coating systems under flowing and static immersion condition has been monitored using electrochemical impedance spectroscopy (EIS) when exposed to 3% NaCl aqueous solution at 60°C. The aim of this project was to determine the impact of flowing condition on the degradation of the protective properties of polymer coatings during exposure to corrosive medium. Using a rotating cylinder apparatus, the immersion tests under the flowing condition were performed. The relative permittivity of coating, , where the coating capacitance C c was calculated from the high frequency data of impedance spectrum, was selected as the index to monitor property variation with immersion time. Experimental results showed that the flowing condition aggravated the deterioration of coatings. The results were interpreted in terms of a model in which flowing condition changes coating/solution interface state and then accelerates the ions to diffuse through the coating. The electrochemical results were in agreement with the final visual observation. The present investigation suggests that flowing test provides an effective accelerating way to evaluate the degradation of coating system. [Copyright &y& Elsevier]

A study was performed on the damage effects and mechanisms of proton irradiation with 150 keV energy to space-grade methyl silicone rubber. The changes in surface morphology, mechanical properties, infrared attenuated total reflection (ATR) spectrum, mass spectrum and pyrolysis gas chromatography–mass spectrum (PYGC–MS) indicated that, under lower fluence, the proton radiation would induce cross-linking effect, resulting in an increase in tensile strengths and hardness of the methyl silicon rubber. However, under higher proton fluence, the radiation-induced degradation, which decreased the tensile strengths and hardness, became a dominant effect. A macromolecular-network destruction model for the silicone rubber radiated with the protons was proposed. [Copyright &y& Elsevier]

In this paper, graded double-layer materials were prepared on TC4 alloy. For the first layer, WC particles were injected into the surface of the TC4 in order to mitigate the CTE of the TC4 substrate. For the second layer, Cu-Ni-WC powder was cladded on the first layer for improving the plasticity. Thermal expansion coefficients, microstructures, and sectional hardness distribution of the graded layers were characterized and analyzed. The laser treated TC4 was then successfully brazed with the C/C using a Ti foil. Microstructure of the brazed joint was investigated in detail. For comparison, C/C composites and the TC4 alloy were also brazed directly. Results show that Room-temperature shear strength of the brazed joint was improved by 89% when the graded double-layer materials were applied, comparing with the directly brazed joint. Image 1 • Graded double-layer materials were prepared on TC4 surface using a laser cladding approach. • CTE of Layer I adjacent to TC4 containing low-expansion WC particles is much closer to that of the C/C composite. • Layer II with Cu–Ni solid solution possesses desirable ductility. • Shear strength of the C/C-TC4 brazed joints increased by 89% after the preparation of the graded double-layer materials. [ABSTRACT FROM AUTHOR]