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Effects of surfaces/interfaces become prominent in micro- and nanosized materials and devices. In the present paper, the diffraction of plane harmonic compressional waves (P wave) by a spherical nanoinclusion is studied theoretically using the surface/interface elasticity theory. The results demonstrated that when the inclusion size shrinks to nanometers, surface/interface elasticity plays a significant role in the diffraction of elastic waves. For incident waves of different frequencies, the interface effects on the dynamic stress concentration around the spherical inclusion are examined in detail. [ABSTRACT FROM AUTHOR]

The residual stresses due to high-temperature processing in micromultilayer ceramic capacitors (MLCCs) with various thicknesses and numbers of dielectric ceramic layers were investigated by using a three-dimensional elastoplastic finite element model with temperature-dependent material properties taken into account. For comparison, an explicit analytical solution for the in-plane residual stress in the dielectric ceramic layer was derived. Both the numerical results and the analytical model showed that the thickness ratio of the dielectric layer to electrode layer has a dominant impact on the residual stress states. There exists a critical thickness for the dielectric ceramic layer in MLCCs in the case of a given thickness of the electrode layer, below which both high tensile out-of-plane stresses and high compressive in-plane stresses could cause the cracking of the brittle dielectric layers near the electrode tips and/or the debonding of the electrode/dielectric interface. [ABSTRACT FROM AUTHOR]

Based on the surface elasticity theory, we examined the effects of surface stresses on nanosized contact problems. The Fourier integral transform method is adopted to derive the general solution for the contact problem under pressure. As two examples, the deformations induced, respectively, by a uniform distributed pressure and a concentrated force are analyzed in detail. The results indicate some interesting characteristics in contact mechanics, which are distinctly different from those in classical elasticity theory. Both the contact normal stress and the deformation gradient on the deformed surface vary smoothly across the loading boundary as a result of surface stress. In addition, the indent depth and the maximum normal contact stress depend strongly on the surface stress for nanoindentation. [ABSTRACT FROM AUTHOR]

Self-assembly of block copolymer/nanoparticle blends has promising applications in the design and fabrication of novel functional nanomaterials. Precise control of the spatial positions of nanoparticles within block copolymer-based nanomaterials is crucial to achieve some special physical properties and functions. Here, we employ the self-consistent field method to theoretically investigate the self-assembly of polymer grafted-nanoparticles in a diblock copolymer. It is found that by varying the size and selectivity of nanoparticles, one can not only produce various self-assembled nanostructures but also modulate the spatial positions of the nanoparticles, either at the copolymer interfaces or in the center of one copolymer phase, within the nanostructures. A denser grafted polymer brush plays a role of shielding effect on nanoparticles and can position them into the center of one copolymer phase. The nanostructural transition we observed is dictated by the competition between entropy and enthalpy. On the basis of a number of simulations, two phase diagrams of self-assembled nanostructures are constructed. This study may be helpful for optimal design of advanced materials with desired nanostructures and enhanced performance. [ABSTRACT FROM AUTHOR]

Over 100 sherds were collected from Hongzhou Kiln of Jiangxi Province, China and their body samples were analyzed by INAA. The compositional differences between samples with the same period but different provenance were observed. The contents of Na, Rb, Ba, Fe, Th, U, etc., were found to be different among samples from different periods, which implies they may be used to identify the manufacturing age indirectly. The analytical data were further processed by principal components analysis (PCA). The statistical results show that all the sherds can be classified into 5 groups: (1) Eastern Han and Eastern Wu; (2) Western Jin, Eastern Jin and Southern Dynasties; (3) Sui; (4) Early Tang and Middle Tang; (5) Late Tang and Five Dynasties. [ABSTRACT FROM AUTHOR]

We have developed a hybrid continuum/atomistic model to study Stone–Wales transformation in single wall carbon nanotubes. The atoms far away from the defect are characterized by an atomistic-based continuum theory established from the interatomic potential, while atom positions in the vicinity of the defect are determined by molecular mechanics coupled with the atomistic-based continuum theory. For a carbon nanotube in tension, the hybrid continuum/atomistic model predicts a critical strain 4.95% for Stone–Wales transformation, which is in excellent agreement with prior molecular dynamic studies. For a carbon nanotube in torsion, the present study predicts a critical shear strain of 12%. [Copyright &y& Elsevier]

The states of hyperchaos appearing in degenerate optical parametric oscillators (DOPOs) can be controlled by means of a resonance created using three-wave interaction. For a given set of detuning parameters, the reduced rate of the fundamental mode damping, and the initial field amplitude, any desired periodic orbit in DOPOs can be obtained by appropriate adjustment of the control wave amplitude. The proposed approach is illustrated by the results of numerical calculations. [ABSTRACT FROM AUTHOR]

Almost all solid surfaces have roughness on different length scales, from macro, micro to nano. In the conventional fractal contact model, the macroscopic Hertzian contact theory is employed to predict the contact load-area relation for all sizes of contact spots. However, when the contact radius of an asperity shrinks to nanometers, surface tension may greatly alter the contact behavior. In the present paper, we address surface effects on the contact between a rigid sphere and an elastic half space, and we demonstrate that the contact load-area relation is size-dependent, especially for nanosized asperities. Then, the refined contact relation is incorporated into the Majumdar-Bhushan fractal contact model. It is found that the presence of surface tension requires higher load than the conventional fractal contact model to generate the same real contact area. [ABSTRACT FROM AUTHOR]

Bovine horn is composed of a sheath of keratin overlying a bony core. Previous studies of the bovine horn sheath have focused mainly on its morphology and compositions. In the present paper, we performed a series of uniaxial tension, three-point bending, and fracture tests to investigate the structural and mechanical properties of the horn sheaths from subadult cattle, Bos taurus. The effects of hydration on the mechanical properties were examined and their variations along the longitudinal direction of the horn sheath were addressed. Scanning electron microscopy of the fracture surfaces showed that the horn sheath has a layered structure and, more interestingly, the laminae have a rippled appearance. The Young's modulus and tensile strength increase from 850MPa and 40MPa at 19% water content to 2.3GPa and 154MPa at 0% water content, respectively. The Poisson's ratio of the horn sheath was about 0.38. The critical stress intensity factor was about 4.76 MPa m½ at an intermediate hydration (8% water content), greater than that at 0% water content (3.86MPam½) and 19% water content (2.56MPam½). The bending properties of the samples varied along the length of the horn. The mean flexural moduli of the specimens in the distal, middle and proximal parts were about 6.26GPa, 5.93GPa and 4.98 GPa, respectively; whereas the mean yield strength in the distal segment was about 152.4MPa, distinctly higher than that in the middle (135.7MPa) and proximal parts (116.4MPa). This study deepens our understanding of the relationships among optimal structure, property and function of cattle horn sheaths. [ABSTRACT FROM AUTHOR]

On the physical nature, most crack tips are not ideally sharp but have a small curvature radius. Both surface energy and crack-root curvature affect the stress and displacement fields in the vicinity of the crack tip. In the present paper, a numerical method, which incorporates the effect of surface elasticity into the finite element method, is employed to study the surface effects on the mode-II crack tip fields. It is found that when the curvature radius of the crack root decreases to micro-/nanometers, surface elasticity has a significant influence on the stresses near the crack tip. For a mode-II crack, surface effects alter both the magnitude and position of the maximum stresses, as is different from a mode-I crack, in which case only the stress magnitude is influence by surface stresses. [ABSTRACT FROM AUTHOR]

In order to group specimens of Tang Sancai of unknown provenance to the different kilns according to their chemical compositions, we studied the elemental abundance patterns of Tang Sancai body samples from different tombs, relics and kilns by instrumental neutron activation analysis (INAA). Our results indicated that the development process of Tang Sancai in the Prospering Tang period could be divided into at least two phases, withad 705 or so as the boundary between them. The results of factor analysis showed that the red-bodied samples were more likely to be produced near Xi’an, whereas the white-bodied Tang Sancai wares dating to beforead 705 were most probably produced at Huanye Kiln (also known as ‘Gongxian’ Kiln), and the figures were very likely made at an undiscovered kiln near Luoyang or an undiscovered part of Huangye Kiln. Among the white-bodied samples dated fromad 705 toad 755, both types of figures and wares were mainly produced near Xi’an and Luoyang. [ABSTRACT FROM AUTHOR]

Study of the interaction and evolution behaviour of adatoms is fundamental to many surface phenomena. In the present paper, a continuum mechanics method, based on the force dipole concept, is presented to study the evolution of adatoms adsorbed on a smooth or stepped surface. The effects of elastic and van der Waals interactions are examined. It is found that the elastic interaction among adatoms usually serves as the main driving force for the clustering behaviour of adatoms and that the presence of surface defects, such as steps, may significantly influence the evolutionary arrangement of interacting adatoms. [ABSTRACT FROM AUTHOR]

The occupational health impact of atmospheric pollution on exposed workers at one iron and steel complex was studied by instrumental neutron activation analysis of workers' hair samples and medical examination. The experimental results indicate that there is a positive correlation between the high inhalation amounts of iron and other trace elements by the exposed workers and the symptom of their high blood pressure and hypoglycemia, which implies that the atmospheric environment polluted by iron and steel industry has an adverse health impact on the exposed workers. The measures to relieve and abate the occupational diseases caused by air-borne particulate matter should be taken [ABSTRACT FROM AUTHOR]

An approximate continuum theory is developed to effectively handle the problem of interaction between dislocations and inhomogeneity of any shape and properties. The inhomogeneity is, based on the Eshelby equivalent inclusion theory, equivalent to a homogenous one with a transformation strain. The interaction force between dislocation and the inhomogeneity can then be evaluated from the work done by the dislocation stress field during the transformation. The proposed continuum theory is applicable to a variety of inhomogeneities, such as pore, gas bubble, shear band and plastically deformed zone. It can be reduced to the classical continuum theory for some special cases. [ABSTRACT FROM AUTHOR]

In the present letter, the authors consider the diffraction of plane harmonic compressional wave (P wave) by a nanosized circular hole. The surface elasticity theory is employed to incorporate the surface effects. The results show that once the radius of hole reduces to nanometers, surface energy significantly affects the diffraction of elastic waves. For incident waves with different frequencies, the influences of surface elasticity on dynamic stress concentration are discussed in details. [ABSTRACT FROM AUTHOR]

Summary: Stimulated emission depletion (STED) microscopy performed using continuous‐wave (CW) lasers has been investigated and developed by Willig et al. (Nature Methods, 2007, 4(11):915) for nearly a decade. Kuang et al. (Review of Scientific Instruments, 2010, 81:053709) developed the CW STED microscopy technique with 405 nm excitation and 532 nm depletion beams. In their research, Coumarin 102 dye was adopted and was found to be depletable. In this study, a parametric investigation of the depletion of Coumarin 102 dye is carried out experimentally. The influence of the excitation and depletion beam intensities and dye concentrations on the depletion efficiency are studied in detail. The results indicate the following: (1) The highest depletion occurs for the 100 μM Coumarin 102 solution, with a 1.4 μW excitation beam and a 115.3 mW depletion beam. (2) The minimum saturation intensity ( I s) of STED, that is 13 MW cm–2, is observed when the Coumarin 102 solution concentration is 10 μM. (3) I s values calculated directly from the depletion power derived with the cross‐sectional area due to the full‐width‐at‐half‐maximum (FWHM) of the depletion beam show poor accuracy, where I s may be overestimated. Thus, a correction factor for the cross‐sectional area is proposed. We also find that I s is not exactly constant for a fixed excitation beam power and dye concentration. This trend indicates that the conventional suppression function η ( x ) = e − ln ( 2 ) I STED ( x ) / I s derived from picosecond STED may cause errors in evaluating the depletion process in CW STED microscopy. [ABSTRACT FROM AUTHOR]

A large number of porcelain shards were unearthed at the Hehuaxin and Silongkou kilns around the Shanglin Lake, Ningbo, China, some of which had clear stratification to enable the determination of the date of firing. With the purpose of studying the elemental composition in different cultural periods and between kilns, the chemical compositions of 43 typical shards from these two kilns were determined by energy‐dispersive X‐ray fluorescence (EDXRF). The results show that the mean contents of K2O, CaO and MnO in the glaze fluctuate in different cultural periods at the Hehuaxin kiln, but not systematically. Principal component analysis (PCA) indicates that samples from the Five Dynasties and the Northern Song dynasty are similar to each other. This shows continuity in the raw materials and firing technology between the two dynasties. Comparing the mise type wares from the Hehuaxin and Silongkou kilns in the Northern Song dynasty, we found that MnO and ZrO2 in the glaze can be used as fingerprinting elements to distinguish between samples from these two sites. In spite of this, their chemical compositions are broadly similar. Thus, perhaps, their chemical compositions can be taken as typical for those of the mise type wares produced around the Shanglin Lake. [ABSTRACT FROM AUTHOR]

Samples of celadon were collected from the Altar Guan Kiln in Hangzhou, and from the Xiaomeizhen and Xikou Kilns, two subordinate kilns of the Longquan Kiln producing black‐body celadon called Literature Ge. Both the elemental contents in the sample bodies and the glaze were measured. The results reveal that the sample bodies contain fingerprint information for provenance, while this was lost in the glaze during the production process. The TiO2, MnO and Rb2O contained in the bodies are fingerprints to distinguish between celadons from the Xiaomeizhen and Xikou Kilns. In the Altar Guan Kiln, some low‐TiO2 samples were found and their body colour is much lighter than some others, but they do not differ with regard to iron content. This indicates that both titanium and iron are indispensable for the blackness of the bodies: they may react to form some black minerals during the firing process. Ultimately, samples from the Literature Ge and Altar Guan Kilns differ in their body constituents. Principal component analysis reveals that the samples can be divided into two groups, corresponding to the two different areas. [ABSTRACT FROM AUTHOR]

There is a generally accepted view that there is an obvious distinction between proto‐porcelain and stamped stoneware. However, some early shards unearthed from the Dongtiaoxi region (northern Zhejiang) inspire people to rediscuss the relationship between them, because it is difficult to identify them as proto‐porcelain or stamped stoneware. In this work, we have collected samples from three of the earliest kiln sites (Piaoshan, Beijiashan and Nanshan) in the Dongtiaoxi region. We have analysed the chemical composition, firing temperature and phase composition of the samples. Comparing samples from the three kiln sites, we find that, from Piaoshan and Beijiashan to Nanshan, there has been progression in the manufacturing technology. The Shang proto‐porcelain and the stamped stoneware from Nanshan have similar raw materials, firing temperatures and body phase compositions—and they have obviously different decorative appearances, such as glazing or stamping. For ceramics from Piaoshan and Beijiashan, there is no clear distinction between glazed and unglazed samples. We believe that in the Dongtiaoxi region, the difference in the decoration between proto‐porcelain and stoneware became obvious up to the time of the Nanshan production but that, subsequently, two different paths for the development of high‐fired ceramics began to diverge. [ABSTRACT FROM AUTHOR]

Introduction: The treatment of haemophilia varies across countries and across regions within some countries. Similar variation has been observed in health‐related quality of life (HR‐QoL). Relatively little is known about the HR‐QoL of boys with haemophilia in China. Aim: The aim of this study was to describe the HR‐QoL of boys with haemophilia in China using the Canadian Haemophilia Outcomes‐Kids Life Assessment Tool (CHO‐KLAT). Methods: Boys (4‐18 years of age) with haemophilia and their parents were enroled in a cross‐sectional study. All parents/guardians of study subjects were requested to complete a CHO‐KLAT questionnaire during a clinic visit, and report on several other clinical and socioeconomic factors in the past year. Boys who were > 7 years also completed the CHO‐KLAT. Results: A total of 269 parents of boys with haemophilia, from 13 hospitals in 12 provinces, were enroled during 2014. The boys ranged from 4.0 to 17.9 years of age; 91% had haemophilia A, most had moderate (52%) or severe (36%) disease, and most were receiving sub‐optimal on‐demand therapy or low‐dose prophylactic therapy. Child self‐report CHO‐KLAT scores were available for 171 boys ≥7 years of age and ranged from 24.2 to 85.3 with a mean of 57.6 (n = 171). Parent proxy‐reported CHO‐KLAT scores ranged from 25.0 to 88.7 with a mean of 55.1 (n = 269). Conclusion: HR‐QoL scores in boys with haemophilia in China were substantially lower than reported from Canadian and European boys with haemophilia. Longer term prospective studies are required to examine the factors impacting the HR‐QoL for boys with haemophilia in China. [ABSTRACT FROM AUTHOR]

A mass of Longquan porcelain shards carved with ' Guan' or the dragon patterns were unearthed in the early Ming Dynasty layer of the Fengdongyan kiln site at Dayao County. These celadon shards were fired in the Hongwu and Yongle eras of the Ming Dynasty. In order to research the raw materials and firing technology of the imperial porcelain, 85 typical shards were analysed by energy-dispersive X-ray fluorescence ( EDXRF). The results indicate that the contents of TiO2 and Fe2O3 in the body vary in the Hongwu and Yongle eras. Compared with Longquan glazes in the Southern Song Dynasty, the average values of K2O, Fe2O3 and TiO2 are higher, but that of CaO is lower in early Ming imperial porcelain glazes. Principal components analysis ( PCA) shows that different degrees of elutriation of the same raw materials are the main reason for this difference in the Hongwu and Yongle periods. However, the raw materials of imperial porcelain glazes show no obvious changes and have inherited the earlier tradition. The production and firing technology of imperial porcelain reached a higher level and had not declined in the Early Ming Dynasty. [ABSTRACT FROM AUTHOR]

Xiaoshan in Zhejiang Province was an important ceramic production area in ancient China. During recent years, local archaeologists have found a number of mound tombs dating to the Zhou Dynasty and the Spring and Autumn period. Many shards of stamped stoneware and proto-porcelain have been unearthed from these tombs. In this paper, we report how we collected ceramic shards from tombs and samples from local ancient kilns as reference materials in order to clarify their relationship. We have used the energy-dispersive X-ray fluorescence technique to analyse the chemical composition of the ceramic samples. The results indicate that some of the tomb artefacts may be imported from other production areas. We infer that the other tomb samples were produced at local kilns, but due to production process-related compositional differences, there are small differences in chemical composition between different categories of samples. [ABSTRACT FROM AUTHOR]

Within the thermodynamic framework with internal variables by Rice (1971, "Inelastic Constitutive Relations for Solids: An Internal Variable Theory and Its Application to Metal Plasticity," J. Mech. Phys. Solids, 19(6), pp. 433-455), Yang et al. (2014, "Time-Independent Plasticity Related to Critical Point of Free Energy Function and Functional," ASME J. Eng. Mater. Technol., 136(2), p. 021001) established a model of time-independent plasticity of three states. In this model, equilibrium states are the states with vanishing thermodynamic forces conjugate to the internal variables, and correspond to critical points of the free energy or its complementary energy functions. Then, the conjugate forces play a role of yield functions and further lead to the consistency conditions. The model is further elaborated in this paper and extended to nonisothermal processes. It is shown that the incremental stress-strain relations are fully determined by the local curvature of the free energy or its complementary energy functions at the critical points, described by the Hessian matrices. It is further shown that the extended model can be well reformulated based on the intrinsic time in the sense of Valanis (1971, "A Theory of Viscoplasticity Without a Yield Surface, Part 1. General Theory," Arch. Mech., 23(4), pp. 517-533; 1975, "On the Foundations of the Endochronic Theory of Viscoplasticity," Arch. Mech., 27(5-6), pp. 857-868), by taking the intrinsic time as the accumulated length of the variation of the internal variables during inelastic processes. It is revealed within this framework that the stability condition of equilibrium directly leads to Drucker (1951, "A More Fundamental Approach to Stress-Strain Relations," First U.S. National Congress of Applied Mechanics, pp. 487-497) and Ilyushin (1961, "On a Postulate of Plasticity," J. Appl. Math. Mech., 25(2), pp. 746-750) inequalities, by introducing the consistency condition into the work of Hill and Rice (1973, "Elastic Potentials and the Structure of Inelastic Constitutive Laws," SIAM J. Appl. Math., 25(3), pp. 448-461). Generalized inequalities of Drucker (1951, "A More Fundamental Approach to Stress-Strain Relations," First U.S. National Congress of Applied Mechanics, pp. 487-497) and Ilyushin (1961, "On a Postulate of Plasticity," J. Appl. Math. Mech., 25(2), pp. 746-750) for nonisothermal processes are established straightforwardly based on the connection. [ABSTRACT FROM AUTHOR]

Peel test is an efficient method to assess the performance and characteristics of materials such as adhesives and adhesive tapes. Recent experiments evidenced that the measured adhesive strength is closely related to the shear-induced interfacial slippage near the delamination front due to the concomitant Poisson contraction effect of the adhesive. Based on the experimental observations, a theoretical model is presented in this paper to examine the effect of the shear-induced interfacial slippage in the peel test. The influence of the interfacial slippage, represented by the shear displacement in the cohesive zone, on the fracture energy of decohesive zone is analyzed. An implicit expansion method with a Gauss-Chebyshev quadrature scheme is used to derive the solution. It is found that the length of the slippage zone and the receding contact angle of adhesives are the two most significant contributors to the total fracture energy of the decohesive zone. These results demonstrate that the mechanism of interfacial slippage plays a significant role in the adhesion and peeling behaviors of adhesives. [ABSTRACT FROM AUTHOR]

Abstract: The fracture strain of carbon nanotubes (CNTs) obtained by molecular dynamics is about 30%, which is much higher than the experimental results (10–13%). The present study shows that this difference results mainly from defects in CNTs. As the tensile strain reaches a few percent, defects are nucleated in the form of Stone–Wales transformation (90° rotation of a bond). A bond in the vicinity of rotated bond breaks as the tensile strain reaches about 13%, which agrees well with the experimental results. Therefore, the Stone–Wales transformation is the precursor of CNT fracture. [Copyright &y& Elsevier]