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Daptomycin is a cyclolipopeptide antibiotic produced by Streptomyces roseosporus. It is widely used to treat drug-resistant bacterial infections; however, daptomycin yield in wild strains is very low. To improve the daptomycin production by the strain BNCC 342432, a modified method of ribosome engineering with superposition of streptomycin resistance was adopted in this study. The highest-yield mutant strain SR-2620 was obtained by increasing streptomycin resistance of BNCC 342432, and achieved daptomycin production of 38.5 mg/l in shake-flask fermentation, 1.79-fold higher than the parent strain and its heredity stability was stable. The morphological characteristics of the two strains were significantly different, and the 440th base G of the rpsL gene in the mutant strain was deleted, which resulted in a frameshift mutation. Our results demonstrate that gradually increasing strain resistance to streptomycin was an effective breeding method to improve daptomycin yield in S. roseosporus.

The matrix graphite (MG) of pebble fuel elements for a High Temperature Gas-cooled Reactor (HTGR), composed of 71wt% natural graphite, 18 wt% artificial graphite and 11 wt% phenolic resin-derived carbon, was purified by high temperature treatment (HTT), and its properties and microstructure were analyzed to investigate the effect of different HTT temperatures and optimize the purification temperature. Results showed that with increasing HTT temperature, its density and thermal conductivity gradually increased, but pore size and d002 gradually decreased. The rate of erosion caused by friction as the fuel pebbles move in the reactor also decreased. The ash content decreased significantly from to 18.2×10−6to 12.3×10−6 after HTT at 1600 °C, but changed little when the HTT temperature was further increased to 1900 °C, especially for catalytic metals such as Fe, Ni and Ca that are related to its corrosion rate. The microstructure improvement and ash content reduction at high temperatures jointly contributed to the increase in the anti-corrosion performance of MG. Based on properties such as crushing strength, erosion resistance, and corrosion rate, a HTT of 1600 °C is adequate although the MG gradually became more ordered with a further increase of HTT temperature from 1600 to 1900 °C. This determination of an appropriate HTT temperature for the production of MG for the fuel elements of an HTGR should improve the production efficiency and reduce the mass production cost of this material for a commercial HTGR.

A methodology combining the asymmetrical metal-cladding waveguide (aSMCW) excited ultrahigh-order modes and coarse wavelength induced Vernier effect is theoretically proposed to enhance the sensitivity of the magnetic field sensor. In our aSMCW structure, a transparent glass SF11 with a sub-millimeter scale thickness is selected as the guiding layer, whose magnetically modulated refractive index leads to a variation of resonant wavelength. By controlling the sampling interval of tunable laser, the Vernier effect assisted resonant wavelength shift is more distinguishable and the sensitivity is enhanced about 20 times. Our sensitivity enhancement method is low cost since the optical spectrum analyzer (OSA) with a fine resolution is needless.

SiC/MoSi

SiC/YSiC composite coating was prepared on the surface of matrix graphite sphere by pack cementation and molten salt process to improve the anti-oxidation property of the matrix graphite. According to the experiment results, the composition of the composite coatings prepared with different Y content is the same. While, the crushing model and strength is different. The maximum crushing strength is 1716.2 N when Y content is 1 g. The different coating structure were analyzed according to the results. The coating is composed of inner original SiC layer and outer new formed Si layer when Y content is 0.25 g. When the addition of Y were 0.5 g and 0.75 g, the coating consists of a newly formed YC2 layer inside, a SiC layer in the middle and an external Si layer. The final coating structure is composed of SiC layer and residual Si and YC2 layers when Y content is 1 g.

A dense SiC coating was prepared by fluidized-bed chemical vapor deposition (FB-CVD) process to protect matrix graphite sphere of high temperature gas-cooled reactor fuel element from oxidation. The effect of deposition temperature, atmosphere and the formation mechanisms of the SiC coatings were analyzed. Results show that deposition temperature has a significant influence on coating composition. At lower temperature, the co-deposition of Si occurs; while the co-deposition of C occurs at higher temperature. The atmosphere also can influence the coating phase composition. When the deposition is processed at 1773 K, there appears free Si in the SiC coating with the increase of the concentration of H2 in the atmosphere. The density of the deposited coatings can reach up to 90% of the theoretical density of SiC. The research results show that FB-CVD is an ideal choice for preparing dense SiC coating on the surface of high temperature gas-cooled reactor matrix graphite spheres.

In this paper, through the method of finite element simulation, different power density loads are applied to solder joints in the board level interconnection system to make the maximum temperature of the system reach 50°C, 75 °C and 100°C respectively, and then the drop simulation is carried out to study the reliability of the board level interconnection solder joints under thermal-mechanical coupling. The simulation results show that compared with single drop impact, the application of thermal load reduces the 1st eigenfrequency of PCB and reduces the solder joint stress. With the increase of system temperature, the 1st eigenfrequency of the PCB and the solder joint stress is decreasing, but the solder joint life is increasing. The stress analysis in the height direction of the solder joint found that the bottom surface of the solder joint connected to the PCB board is the location of the largest stress on the solder joint. It is inferred that when the board level interconnection system is impacted by drop, this position will be damaged first.

CQFP devices have been widely used in aerospace, military and other fields due to the advantages of high reliability [1], but large-size CQFP devices are prone to failure after PING test. This paper uses ANSYS Workbench to locate the defect and verify it by scanning electron microscope (SEM). The verification results are consistent with the simulation results. In addition, a test fixture was used to optimize the PIND test process, and the results show that the use of test fixture can effectively reduce the risk of device failure.

A simulation method was utilized to study the electromigration reliability of two daisy chain structures which were subjected to electric current of 0.05 A at environment temperature of 22°C. The current density and temperature distribution of the two daisy chain structures were compared and the electromigration reliability of two types of daisy chain structures were analyzed. The results show that the current crowding effect of typical bump in parallel daisy chain structure was more prominent than that of typical bump in series daisy chain structure. The current density followed eight-order polynomial distribution. The hot spots of both structures coincided with the current crowding regions and the maximum temperature in typical bump in parallel daisy chain structure was obviously higher than that in typical bump in series daisy chain structure. The electromigration reliability of parallel chain structure was lower than that of series chain structure due to higher temperature and higher current density in hot spots of parallel chain structure. These findings will offer fundamental insights into electromigration and reliability theory.

The core components of HTR mainly consist of graphite, which is an excellent solid moderating material and structure material with good irradiation performance. However, graphite is easier to be oxidized at high temperature. It is important to improve the anti-oxidation performance of graphite substrate to enhance the safety of HTR. Anti-oxidation coating has been proved that it can effectively improve the oxidation resistance of graphite substrate. The selection of coating includes the coating materials system and the preparation techniques. In addition, attention also should be paid to the anti-oxidation mechanism. SiC based coating system is most commonly used in HTR and some other coating systems such as zirconium compounds coating, noble metal coating also can be used in nuclear. However, some coating systems are not suitable in HTR because the elements contained cannot be used in high irradiation environment. The emphasis is on the antioxidant mechanism of different coating systems. Some anti-oxidation coating techniques for graphite substrate are also reviewed in this paper, such as PC, CVD, PS and slurry. Finally, the existing problems of the oxidation resistance coating are proposed and an outlook is made for the development of the protection coating system for graphite substrate used in nuclear.

To evaluate the performance of a composite scaffold of Wharton’s jelly (WJ) and chondroitin sulfate (CS) and the effect of the composite scaffold loaded with human umbilical cord mesenchymal stem cells (hUCMSCs) in repairing articular cartilage defects, two experiments were carried out. The in vitro experiments involved identification of the hUCMSCs, construction of the biomimetic composite scaffolds by the physical and chemical crosslinking of WJ and CS, and testing of the biomechanical properties of both the composite scaffold and the WJ scaffold. In the in vivo experiments, composite scaffolds loaded with hUCMSCs and WJ scaffolds loaded with hUCMSCs were applied to repair articular cartilage defects in the rat knee. Moreover, their repair effects were evaluated by the unaided eye, histological observations, and the immunogenicity of scaffolds and hUCMSCs. We found that in vitro, the Young’s modulus of the composite scaffold (WJ-CS) was higher than that of the WJ scaffold. In vivo, the composite scaffold loaded with hUCMSCs repaired rat cartilage defects better than did the WJ scaffold loaded with hUCMSCs. Both the scaffold and hUCMSCs showed low immunogenicity. These results demonstrate that the in vitro construction of a human-derived WJ-CS composite scaffold enhances the biomechanical properties of WJ and that the repair of knee cartilage defects in rats is better with the composite scaffold than with the single WJ scaffold if the scaffold is loaded with hUCMSCs.

The importance of hydroelasticity analysis of large and flexible container ships of today has been pointed out for structure design. Because of the increases of the size of container ships, whipping phenomena has been one of the important design considerations. This paper introduced a 3D nonlinear hydroelasticity theory which utilizes a 3-D Green function method and a 2-D momentum model coupled in time domain. A model system for measurement of nonlinear wave loads which is composed of a backbone and segmented container ship model has been already established, and applied to a series of large ship models, in which natural frequency of vertical bending is matched using a beam. A series of model tests have been carried out for selected cases of whipping in irregular waves. The computational results were compared with those of a model test of a 10,000-TEU containership. The Verifications and validations between model tests result and theoretical calculation have been carried out. The asymmetry of wave elevation, vertical ship motion and vertical sectional loads responses are mainly discussed, they are observed and calculated in irregular wave conditions, and the experimental results accord with simulated results, basing on which the design vertical bending moment at midship can be obtained by using the nonlinear short-term and long-term analysis, and the comparison between direct calculation and classification society rules is carried out, which has much in common.

Rules of Classification Societies all around the world have made changes on design wave loads’ value and fatigue influence factor modification due to the influence of springing and whipping on ultra-large containerships. The paper firstly introduced 3-D linear hydroelastic theory in frequency domain and 3-D nonlinear hydroelastic theory in time domain, considering large amplitude motion nonlinearity and slamming force due to the severe relative motion between ship hull and wave. Then the spectrum analysis method and time domain statistical analysis method were introduced, which can make fatigue analysis under a series of standard steps in frequency and time domain, respectively. Finally, discussions on the influence factor of springing and whipping on fatigue damages of 8500TEU and 10000TEU containerships with different loading states were made. The fatigue assessment of different position on the midship section was done on the basis of nominal stress. The fatigue damage due to whipping can be the same as the fatigue damage due to springing and even sometimes can be larger than the springing damage. Besides, some suggestions on calculating load case selection were made to minimize the quantity of work in frequency and time domain. Thus, tools for fatigue influence factor modification were provided to meet the demand of IACS-UR.

INTRODUCTION: Mechanical stimulation is important for maintaining cartilage function. We used a loading device to exert rolling-sliding mechanical stimulation on cartilage preserved in vitro to investigate cartilage viability and the involved mechanisms. METHODS: Osteochondral grafts from pig knees were randomly classified into loading and control groups. The loading group cartilage was subjected to cycles of mechanical stimulation with specified frequency/time/pressure combinations every 3 days; Then the DMEM was refreshed, and the cartilage was preserved in vitro. The control group cartilage was preserved in DMEM throughout the process and was changed every 3 days. On days 14 and 28, the chondrocyte survival rate, histology, and Young’s modulus of the cartilage were measured. Western blots were performed after 2 h of loading to evaluate the protein expression. RESULTS: The loading group showed a significantly higher chondrocyte survival rate, proteoglycan and type II collagen content, and Young’s modulus than did the control group on day 14, but no statistically significant differences were found on day 28. After two hours of the loading, the phosphorylation levels of MEK and ERK1/2 increased, and the expression of caspase-3, cleaved caspase-3 and bax decreased. CONCLUSION: These results suggest that periodic rolling-sliding mechanical stimulation can increase cartilage vitality in 2 weeks; a possible mechanism is that mechanical stimulation activates the MEK/ERK signalling pathway, thus inhibiting apoptotic protein expression. This loading preservation scheme could be used by cartilage tissue banks to improve cartilage preservation in vitro and enhance the quality of cartilage repair.

A multi-layered SiC coating was prepared on graphite spheres to improve its antioxidant performance. The oxidation behaviour of the coating prepared on graphite sphere in static air was studied systematically for the first time. As an antioxidant layer, the dense block layer is effective in protecting the internal transition layer and refined grain layer from oxidation in static air at 1773 K. An amorphous SiO2 layer developing on the surface acts as a protective shell, while some carbon particles developed at the interface of oxide layer and SiC coating. As for the oxidation process of the SiC coated graphite sphere, it is comprised of three stages. Stage I (0−6 h) is characterized by a rapid weight gain, which follows a linear model, and the passive oxidation of SiC occurs in this stage. Stage II (6−50 h) is characterized by a slow weight gain, which follows the parabolic oxidation model. Stage III (50−200 h) is characterized by an invariable weight gain of merely 0.52%, which is accompanied with the interface reaction of SiC and the self-healing of oxide layer.

A two-step pack cementation technique was applied to synthesize the TiSi2–Si–SiC/SiC bilayer coating on the surface of graphite spheres for improving its antioxidant performance. Then, an investigation was conducted into the microstructure, phase composition, formation mechanism, and the isothermal oxidation behavior in static air of the coating. According to the research results, the coating consists of an internal SiC layer and an external TiSi2–Si–SiC layer. In the external layer, the gap between SiC particles filled with Si phase ensures the sufficient compactness of the as-prepared coating, while the small TiSi2 particles are embedded in SiC particles. In the oxidizing environment, TiSi2 is preferentially oxidized to reduce the consumption of SiC, thus ensuring the stability of the coating. The structure of the external layer is capable to ensure the excellent antioxidant performance of the coating. After being oxidized in static air at 1500 °C for 200 h, the weight gain of the coated graphite sphere reached merely 0.96 w.t.% and the thickness of the oxide layer was approximately 20 μm.

A micro four-layer SiC coating, which includes inner transition layer, fine-grained layer, dense bulk layer, and outer loose layer, was fabricated on the matrix graphite spheres of high-temperature gas-cooled reactor fuel elements to improve the oxidation-resistant property by a two-step pack cementation process. According to the experiment results, the micro four-layer can be differentiated by SiC grain size and microstructure variation. The oxidation tests at 1773 K for 200 h reveal that the coating structure could effectively improve the oxidation resistance of matrix graphite spheres with a weight gain of 0.52 wt%, and the fine-grained and dense bulk layers are evidenced as two main antioxidation layers. Although the thermal expansion coefficients of SiC and matrix graphite do not match each other so well, no obvious stress cracking was observed after thermal shocking tests from 1773 K to room temperature for 100 times.

As the main components of the matrix graphite of pebble fuel elements for HTR-PM, the natural flake graphite powder (NFGP) and artificial graphite powder (AGP) must present suitable microstructural features such as specific surface area (SSA), particle size distribution (PSD), and ash contents. As a regular method, the graphite powders are purified at high temperature of ~2500 °C with the purge of halogens to obtain their high purity prior to the powder treatments such as pulverizing, shaping, and particle classification, which may introduce impurities into the graphite powders during the powder treatment process. Therefore, the purification of NFGP and AGP should be carried out after the powder treatment to prevent the graphite powders from being contaminated and reduce the cost. In this manuscript, the microstructural features of NFGP and AGP before and after purification were comparatively analyzed to figure out the effects of purification process on the microstructures of NFGP and AGP. Results showed that purification had great influences on the ash contents and the contents of impurity elements, SSA, and degree of graphitization of graphite powders. However, the purification had little influence on the PSD of graphite powders. The significant decrease of SSA of graphite powders through the purification was due to the reduction of BJH adsorption cumulative volume and porosity. Comparing with those of the NFGP, the properties and microstructure of the AGP changed more through the purification process, which was probably due to the original un-graphitized coke of AGP before purification.

To improve the anti-oxidation ability of graphite, Al2O3 and SiC as additives, a uniform SiC coating was prepared on the surface of HTR graphite spheres by the pack cementation and sintering process. The microstructure of SiC coating was characterized by XRD, Raman spectroscopy, scanning electron microscopy, and the effect of Si/C ratio, Al2O3 and SiC content in the starting powder, sintering process conditions on the microstructure of SiC coating was also analyzed. The results show that the SiC coating on the surface of spherical graphite sample can be obtained with Si/C ratio higher than 3: 1, and the SiC coatings with different raw materials possess different microstructure and phase constitutes. The SiC coating is a kind of clear porous microstructure, while the main composition of the coating is β-SiC with some α-SiC and unreacted graphite. It is found that the content of Al2O3 has a significant influence on the penetration into the SiC coating, while the SiC content has a great influence on the microstructure between SiC coating and the substrate. When Al2O3 content is 10%, the bonding between the SiC coating and the substrate is better. When SiC content is 20%, the SiC coatings obtained have good densification and less lamellar accumulation of on the surface of the coatings. The SiC coatings sintered in Ar gas at 1750 °C have larger thickness and porous porosity microstructure, and the maximum thickness, about 400 ∼ 600 μm, can be achieved with the 2h of sintering time. The obtained SiC coatings sintered in vacuum at 1750 °C have a plate-like dense microstructure, in which the main composition of the coating is free Si, α-SiC and β-SiC, and the transitional area between SiC coating and the substrate is not obvious.

As an ideal antioxidant and anti-apoptotic substance, hydrogen (H2) has protective effects on many isolated organs, such as the heart, lung and kidney. In this study, we explore whether H2 improves the preservation effect of osteochondral allograft by adding it to Dulbecco’s Modified Eagle Medium (DMEM) solution during the tissue culture stage. The osteochondral allograft apparatus was used to harvest 60 pieces of cylindrical allografts (l = 10 mm, d = 6 mm) cartilage in the lateral loading area of the femoral condyle from the pig knee joint in the aseptic condition, and the grafts were randomly divided into 4 groups: Control group (DMEM solution without hydrogen); H-1 group (DMEM solution with hydrogen concentration of 0.2 mmol/L); H-2 group (DMEM solution with hydrogen concentration of 0.4 mmol/L); and H-3 group (DMEM solution with hydrogen concentration of 0.8 mmol/L). The chondrocyte viability, histological changes (hematoxylin and eosin staining, Safranine O staining, and collagen type II immunohistochemistry staining) and biomechanical properties (Young’s modulus) of the osteochondral allograft were investigated after 28 days’ storage. The chondrocyte viability and proteoglycan and collagen type II contents in the H-3 and H-2 groups were higher than that in the Control and H-1 groups, and the H-3 group had the highest values. However, significant differences were not observed between the four groups based on Young’s modulus. Hydrogen as an additive to the DMEM solution improved the preservation effect of osteochondral allograft. The preservation effect of hydrogen occurred in a concentration-dependent manner.

In hydroelastic model tests, segmented ship models are usually used to make sure that the model scale and the full size ship satisfy the similarity law of structural natural frequency and distribution of ship bending stiffness. However, springing barely occurs in those tests because the natural frequency of segmented ship models is too high for the regular waves required to be generated in a tank. In order to investigate the springing effect, three sets of backbone of variable cross section are adopted in the test. One set of backbones satisfies the similarity law of natural frequency, and two extra sets of low stiffness backbones are used so that the springing effect can appear and be measured. Experimental results show that the springing occurs when the wave encounter frequency coincides with the first elastic natural frequency of the ship, or with half or one-third of it. A good agreement has also been obtained between the experimental and the numerical results by a three-dimensional (3D) hydroelasticity method. Based on these results, the contribution of the springing responses to the fatigue damage of the ship is estimated and analyzed.

There are many factors to consider in the field of tissue engineering. For articular cartilage repair, this includes seed cells, scaffolds and chondrotrophic hormones. This review primarily focuses on the seed cells and scaffolds. Extracellular matrix proteins provide a natural scaffold for cell attachment, proliferation and differentiation. The structure and composition of tissue-derived scaffolds and native tissue are almost identical. As such, tissue-derived scaffolds hold great promise for biomedical applications. However, autologous tissue-derived scaffolds also have many drawbacks for transplantation, as harvesting autografts is limited to available donor sites and requires secondary surgery, therefore imparting additional damage to the body. This review summarizes and analyzes various cell sources and tissue-derived scaffolds applied in orthopedic tissue engineering.

Exosomes are extracellular vesicles with diameters of 30–100 nm that are key for intercellular communication. Almost all types of cell, including dendritic cells, T cells, mast cells, epithelial cells, neuronal cells, adipocytes, mesenchymal stem cells, and platelets, can release exosomes. Exosomes are present in human body fluids, such as urine, amniotic fluid, malignant ascites, synovial fluid, breast milk, cerebrospinal fluid, semen, saliva, and blood. Exosomes have biological functions in immune response, antigen presentation, intercellular communication, and RNA and protein transfer. This review provides a brief overview of the origin, morphological characteristics, enrichment and identification methods, biological functions, and applications in tissue engineering and neurological diseases of exosomes.

High temperature oxidation behavior of SiC coatings in tristructural-isotropic (TRISO) coated particles is crucial to the in-pile safety of fuel particles for a high temperature gas cooled reactor (HTGR). The postulated accident condition of air ingress was taken into account in evaluating the reliability of the SiC layer. Oxidation tests of SiC coatings were carried out in the ranges of temperature between 800 and 1600 °C and time between 1 and 48 h in air atmosphere. Based on the microstructure evolution of the oxide layer, the mechanisms and kinetics of the oxidation process were proposed. The existence of silicon oxycarbides (SiOxCy) at the SiO2/SiC interface was demonstrated by X-ray photospectroscopy (XPS) analysis. Carbon was detected by Raman spectroscopy at the interface under conditions of very high temperatures and long oxidation time. From oxidation kinetics calculation, activation energies were 145 kJ/mol and 352 kJ/mol for the temperature ranges of 1200–1500 °C and 1550–1600 °C, respectively.

The improvement of the oxidation resistance of fuel element matrix graphite used in high temperature gas-cooled reactor (HTR) is indispensable for the further improvement of the safety of HTR. The stability of SiC coatings and SiC/SiO 2 multilayer coatings in helium with little impurities is analyzed on the basis of thermodynamic calculation and it is found that SiC/SiO 2 multilayered coatings are suitable oxidation resistant materials for graphite used in HTR fuel elements because they are stable both at the normal operation conditions and accidental conditions of HTR. SiC/SiO 2 multilayer coatings were synthesized on the surface of fuel element matrix graphite of HTR by combination of vapor reaction diffusion, slurry method and high temperature oxidation in air; the oxidation behavior of SiC/SiO 2 coated fuel element matrix graphite of HTR in different atmosphere are investigated and it is shown that SiC/SiO 2 coatings can keep their stability under different experiment conditions which graphite used in HTR may encounter and greatly improve the oxidation resistance of fuel element matrix graphite of HTR.

A novel family of lanthanide hybrid frameworks, {[Ln2(IDA)3]·(H2O)2}n (Ln = Nd (1), Eu (2), Tb (3), Dy(4); H2IDA = iminodiacetic acid), has been synthesized from the self-assembly of the lanthanide ions (Ln3+) with iminodiacetic acid under hydrothermal conditions and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. Structural analyses revealed 1–4 have intricate frameworks with three-dimensional (3D) Ln–O–Ln inorganic connectivity, in which the IDA2- − ligands adopt the different μ(3- and μ(4- bridging forms. The 3D inorganic skeleton of the hybrid can be described as helices of corner-sharing LnN1O8 polyhedra connected by edge-sharing dinuclear Ln2N4O12 units, specified by the Schlafli symbol of 8·.8·.103 as a 82·.10-a (lig) topology. The structures also show intersected lanthanide oxide ring channels occupied by guest water molecules, based on which the reversible de-/rehydration occurs. Photoluminescence measurements indicate 2 and 3 are red and green emitters, respectively, in the solid state at room temperature. Besides, the magnetic properties of 1 have been studied.

As the sea transport demand increases constantly, marine corporations around the world are pursuing solutions with large scale and low cost, which makes ultra large containerships’ construction consequentially. Ultra large containerships are more flexible relatively, and the 2-node natural frequency can easily fall into the encountered spectrum frequency range of normal sea state. Meanwhile, as the speed of containerships is high and its large bow flare, when sailing with high speed, the bow structures may suffer severe slamming forces which can increase the design wave loads’ level and the fatigue damage. The importance of hydroelastic analysis of large and flexible containerships of today has been pointed out for structure design. Rules of Many Classification Society have made changes on design wave loads’ value and fatigue influence factor modification. The paper firstly introduced 3-D linear hydroelasticity theory to calculate the Response Amplitude Operator (RAO) in frequency domain, and then described 3-D nonlinear hydroelasticity theory to obtain the nonlinear wave loads time history in irregular waves in time domain, considering large amplitude motion and slamming force due to severe relative motion between ship hull and wave. Based on the theories, computer programs are made to conduct the calculations under specified load case, and some calculation and statistical results are compared with experimental results to verify the accuracy and stability of the programs secondly. The paper focused on the influence of springing and whipping on fatigue damages of 8500TEU and 10000TEU containerships in different loading cases, using spectrum analysis method and time domain statistical analysis method. The spectrum analysis method can calculate fatigue damage due to low-frequency wave loads and high-frequency springing separately, while the time domain statistical analysis can calculate fatigue damage due to the high-frequency damping whipping additionally, based on 3-D time domain nonlinear hydroelasticity wave loads’ time series simulation in irregular waves and rain flow counting method. Finally, discussions on influence factor of springing and whipping with different loading cases are made. Based on these two containerships in example, the fatigue damage due to whipping can be the same as the fatigue damage due to springing and even sometimes can be larger than the springing damage. According to the wave loads influence factor, the fatigue assessment of different position on midship section is done on the basis of nominal stress. Besides, some suggestions on calculating load case selection are made to minimize the quantity of work in frequency and time domain. Thus the tools for fatigue influence factor modification are provided to meet the demand of IACS’ UR[1].

For ultra large ore carriers, springing response should be analyzed in the design stage since springing is the steady-state resonant vibration and has an important effect on the fatigue strength of hull structure. The springing response of a 550,000 DWT ultra large ore carrier has been studied by using experimental and numerical methods. A flexible ship model composed of nine segments was used in the experiment. The model segments were connected by a backbone with varying section, which can satisfy the request of natural frequency and stiffness distribution. The experiments in regular waves were performed and the motions and wave loads of the ship were measured. The experimental results showed that springing could be excited when the wave encounter frequency coincides with half or one-third the flexural natural frequency of the ship. In this paper, the analysis of the hydroelastic responses of the ultra large ore carrier was also carried out using a 3-D hydroelastic method. Comparisons between experimental and numerical results showed that the 3-D hydroelastic method could predict the motions and the vertical bending moments quite well. Based on this numerical method, the fatigue damage was estimated and the contribution of springing was analyzed.

Zirconium carbide (ZrC) layer on pyrocarbon-coated particles was successfully prepared in a fluidized bed coater furnace by chemical vapor deposition using a zirconium chloride (ZrCl 4 ) vapor method and quantitative controlling of the Zr-source through a ZrCl 4 powder feeder. The crystal phase, microstructure and chemical composition of ZrC-coating layer were analyzed using X-ray diffraction (XRD), optical metallographical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscope (HR-TEM) and X-ray photoelectron spectroscopy (XPS). The results show that the deposited ZrC-coating layer has smooth and compact surface, no obvious holes, clear interface with dense pyrocarbon layer, and a thickness of 35 μm. The main phase of ZrC-coating layer is fcc-ZrC crystal, which is composed of small grains with the size of 20–50 nm. The grain size increases monotonously with the deposition temperature increasing. The main elements of ZrC-coating layer are Zr and C, and the Zr/C molar ratio is close to 1:1. The analysis of composition and crystal structure suggest that a stoichiometric fcc-ZrC crystal was obtained and no obvious preferred orientation of the grains was found.

Porous silicon carbide ceramics were prepared through the coat-mix method and molding, carbonization and sintering process with silicon powders and phenolic resin as raw materials. The crystalline phase, microstructure, and porosity of samples treated at different stages were characterized. Results showed that the fabricated porous silicon carbide ceramics consist of pure β-SiC phase with a homogeneous structure and porosity of above 60%. Each of the processing stages, including coat-mix, molding, carbonization, and sintering, has certain contribution to the porosity of the final porous silicon carbide ceramics, in which the mole ratio of resin carbon to silicon and the molding temperature are the main factors to affect the porosity. A porosity evolution process of porous silicon carbide ceramics during fabrication process was also proposed.

The core-shell structure silicon-resin precursor powders were synthesized through coat-mix process and addition of Al 2 O 3 -SiO 2 -Y 2 O 3 composite additives. A series of porous silicon carbide ceramics were produced after molding, carbonization and sintering. The phase, morphology, porosity, thermal conductivity, thermal expansion coefficient, and thermal shock resistance were analyzed. The results show that porous silicon carbide ceramics can be produced at low temperature. The grain size of porous silicon carbide ceramic is small, and the thermal conductivity is enhanced significantly. Composite additives also improve the thermal shock resistance of porous ceramics. The bending strength loss rate after 30 times of thermal shock test of the porous ceramics which were added Al 2 O 3 -SiO 2 -Y 2 O 3 and sintered at 1 650 °C is only 6.5%. Moreover, the pore inside of the sample is smooth, and the pore size distribution is uniform. Composite additives make little effect on the thermal expansion coefficient of the porous silicon carbide ceramics.

The density of porous pyrocarbon layer of coated fuel particles is one of the important parameters of the coated fuel particles. It directly affects the performance of fuel elements. A measurement method, particle size analyzer method, to analyze the density of porous pyrocarbon was developed, and the standard uncertainty of this method was analyzed. Results showed that the particle size analyzer method has the advantages of fast measurement, large sampling number and high measurement accuracy. This method is very efficient for engineering application and is a promising candidate method to measure the density of porous pyrocarbon of coated fuel particles.

In the field of structural health monitoring of concrete bridges, one of the most challenging problems is the crack identification. In our previous study, we proposed a crack-sensitive skin to monitor the crack initiation and development in a structure and to visualize them remotely using computer. However, the material used in the sensitive skin is not suitable for large-scale structural monitoring. In this article, magnetic wire smart film is proposed for crack monitoring of large-scale concrete structures. Fabrication of the smart film, the working principle of the film, and the application of the film on a real bridge will be presented and discussed. The results show that the smart film is a good technique for crack monitoring of large-scale concrete structures.

Aluminum nitride (AlN)/borosilicate glass composites were prepared by the tape casting process and hot-press sintered at 950 °C with AlN and SiO2-B2O3-ZnO-Al2O3-Li2O glass as starting materials. We characterized and analyzed the variation of the microstructure, bulk density, porosity, dielectric constant, thermal conductivity and thermal expansion coefficient (TEC) of the ceramic samples as a function of AlN content. Results show that AlN and SiO2-B2O3-ZnO-Al2O3-Li2O glass can be sintered at 950 °C, and ZnAl2O4 and Zn2SiO4 phase precipitated to form glass-ceramic. The performance of the ceramic samples was determined by the composition and bulk density of the composites. Lower AlN content was found redounding to liquid phase sintering, and higher bulk density of composites can be accordingly obtained. With the increase of porosity, corresponding decreases were located in the dielectric constant, thermal conductivity and TEC of the ceramic samples. When the mass fraction of AlN was 40%, the ceramic samples possessed a low dielectric constant (4.5∼5.0), high thermal conductivity (11.6 W/(m·K)) and a proper TEC (3.0×10−6 K−1, which matched that of silicon). The excellent performance makes this kind of low temperature co-fired ceramic a promising candidate for application in the micro-electronics packaging industry.