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A simulation-based probabilistic method is proposed for assessing the reliability of steel-lined and prestressed fiber-reinforced concrete (PFRC) slabs against the impact loads. The impact testing of several prestressed and non-prestressed FRC slabs of 800 × 800 × 100 mm in size was carried out. The experimental program involved projectile impact testing of prestressed and non-prestressed FRC slabs using a gas gun. Three parameters were varied for testing of slabs under the projectile impact, viz., a quantity of steel fibers in the concrete, steel lining on the backside of the slab, and the prestressing level. The probability-based reliability analysis of all the tested specimens was then performed to highlight the influence of steel lining, steel fibers, and prestress in enhancing the safety of RC (reinforced concrete) slabs against projectile impacts. Projectile impact velocity exceeding the slab’s ballistic limit was assumed to lead to the failure of the PFRC slab, i.e., the perforation failure of the slab. Study results indicate that when no steel fiber was present, slab reliability was low. Adding fibers to slabs increases slabs’ reliability significantly. Specimens with the highest steel fiber content (1.2%) showed the greatest increase in reliability. The steel lining on the back face makes the slab’s reliability almost doubled in comparison with those without lining. Additionally, steel lining makes the PFRC slabs as reliable as desired. It was further noticed that the prestressing helps in enhancing the slab safety against projectile impacts. Even a minimal amount of prestressing makes a noticeable improvement in the reliability of PFRC slabs.

Heterogeneous solids, also known as cellular materials, have significant advantages for impacting energy absorption and blasting effect attenuation. This study focuses on analysing the stress wave propagation in the heterogeneous solids using a novel meso-scale model through an experimental analysis. Six different specimens were designed and manufactured for this experiment and suitable apparatuses were selected and assembled to satisfy the test requirements to maximise the accuracy and reliability. The experiment provided a clear understanding of the wave propagation characteristics, and it was found that when the structure of transmission medium increases in complexity and the input frequency of stress waves becomes higher, the negative effects on the output will become more significant.

Pseudorabies (PR) outbreaks have devastated many swine farms in several parts of China since late 2011. The outbreak-associated pseudorabies virus (PRV) variant strains exhibited some typical amino acid changes in glycoprotein E (gE), a diagnostic antigen used for discriminating between PRV-infected and vaccinated animals (DIVA). To counteract the potential impact of epitope variations on current serological diagnostics of PRV, we produced monoclonal antibodies (mAbs) against gE protein of one representative PRV variant strain and developed a blocking immunoperoxidase monolayer assay (b-IPMA) for DIVA. The b-IPMA was based on the inhibition of binding between PRV-infected cells and mAb by PRV-specific antibodies present in clinical swine sera and was validated by comparison with a commercial PRV gpI Antibody Test Kit (IDEXX Laboratories, USA). The diagnostic sensitivity, diagnostic specificity and agreement were determined to be 99.25%, 98.18% and 99.02% respectively upon testing 509 serum samples. b-IPMA detected only PRV-specific antibodies and showed no cross- -reactivity with antibodies elicited by gE-deleted vaccine or other common swine pathogens. Thus, b-IPMA has the potential to be used for high-throughput screening of PRV-infected animals in veterinary clinics.

This paper studies the trajectories and loads of rigid projectiles penetrating into concrete targets with oblique and attack angles, based on differential area force law with an empirical model of free surface effect. Investigations are conducted using 450kg, 300-mm-diameter ogive-nose projectiles, with striking velocities from 600 to 1000m/s, oblique angles from 5° to 25° and attack angles from 1° to 5°. The characteristics of trajectories and loads are summarized. An important characteristic is that the turning of trajectory direction only happens at the earlier stage of penetration, and then the trajectory converge to straight line and keep linear motion until the end. Consistent with the trajectory, the attack angle, lateral acceleration and moment all occur at this stage. The axial acceleration is mainly determined by the initial velocity, but the lateral acceleration and moment are determined not only by initial velocity but also by the initial oblique and/or attack angles. In terms of maximum loads of lateral acceleration and moment, the combined influence of initial oblique and attack angles is larger than a single factor. There exist a proper negative attack angle which can minimize the trajectory turning in oblique penetration cases

Three groups of projectiles with different CRH values of ogive-nose, mass center locations, and cone angles of shank are designed to study trajectory and loads of oblique penetration into concrete targets. Impact conditions are taken as striking velocity 600m/s, initial oblique angle 30° and concrete target with compressive strength of 30Mpa. We employed a general differential area force law (DAFL) model of rigid projectile for oblique penetration. An empirical model of free surface effect is proposed for brittle targets. It is shown that structure characteristics have significant effects on trajectories and loads for oblique penetration, i.e. (a) The larger the CRH values, and the closer the mass center locations to the projectile end, the larger the turning angles and lateral deviations of penetration trajectories are. (b)The trajectories of projectiles with ‘cone+ogive-nose’ structures show more stable than those with ‘cylinder+ogive-nose’. (c)All trajectories converge to straight line (linear motion) until stop in the targets, and the trajectories can be divided into turning stage and linear motion stage.

Aim To investigate the role of p300 in the regulation of proliferation and odontogenic differentiation of human dental pulp cells (HDPCs). Methodology The recombinant lentiviral vector pshRNA-copGFP was used to knock-down p300 expression in HDPCs. Protein level of acetylated H3 was detected. The proliferation of HDPCs was measured using the CCK8 assay. The cell cycle and apoptosis were analysed using flow cytometry and TUNEL staining, respectively. The expression levels of Cdc25A, p21waf1 and the cleaved products of caspase 3 and caspase 7 were determined utilizing real-time quantitative polymerase chain reaction and Western blotting analysis. The alkaline phosphatase (ALP) activity was measured, and the formation of mineralized nodules was assessed using alizarin red staining after the induction of odontogenic differentiation of HDPCs. The expression levels of the odontogenic differentiation markers DMP-1, DSPP and DSP were detected utilizing real-time quantitative polymerase chain reaction and Western blotting analysis. Results After p300 was knocked down in HDPCs, p300 was significantly down-regulated at both the mRNA and protein levels, and histone H3 acetylation was reduced. The proliferation capacity of HDPCs was suppressed in p300 knock-down groups. The cells were arrested in the G0/G1 phase of the cell cycle, and cell apoptosis was triggered. ALP activity, the formation of mineralized nodules and the expression levels of DMP-1, DSPP and DSP were all decreased in p300-knock-down HDPCs undergoing odontogenic differentiation. Conclusion Knocking down p300 restrains the proliferation and odontogenic differentiation potentiality of HDPCs.

This article summarises Professor Norman Jones’ academic career and his scholarly contributions to impact engineering. In the past 50 years, Professor Jones has performed profound research on a wide range of impact engineering problems, supervised postgraduate students, researchers and academic visitors from all over the world, initiated international research networks and conferences, and has played important roles in consulting government bodies and in generally serving the academic community. Due to his research excellence and achievements, Professor Jones has received numerous prestigious awards and titles including Fellowship of the Royal Academy of Engineering and Foreign Fellowship of the Indian National Academy of Engineering.Copyright © 2016 by ASME

In plasticity theory, the effective stress–strain curve of a metal is independent of the loading path. The simplest loading path to obtain the effective stress–strain curve is a uniaxial tensile test. In order to demonstrate in a plasticity laboratory that the stress–strain curve is independent of the loading path, the hydrostatic bulge test has been used to provide a balanced biaxial tensile stress state. In our plasticity laboratory we compared several different theories for the hydrostatic bulge test for the determination of the effective stress–strain curve for two representative metals, brass and aluminium alloy. Finite element analysis (FEA) was performed based on the uniaxial tension test data. It was shown that the effective stress–strain curve obtained from the biaxial tensile test (hydrostatic bulge test) had a good correlation with that obtained in the uniaxial tensile test and agreed well with the analytical and FEA results. This paper may be used to support an experimental and numerical laboratory in teaching the concepts of effective stress and strain in plasticity theory.

China’s entry to the World Trade Organization (WTO) will allow both domestic and overseas construction firms to compete under the same market conditions. This development will lead to a more rigorous participation from overseas construction professionals in the Chinese construction market. Nevertheless, this participation can only be effective or successful when there is a proper understanding about the construction procurement practice in China. The Chinese construction practice has its own characteristics, such as governmental regulations, professional qualification systems, and procurement systems. These characteristics present a different practice in awarding construction contracts from that in the West. This paper investigates the characteristics of construction business environment in China and identifies the key parameters used in assessing contractors’ competitiveness for awarding construction contracts in the market. The parameters are useful tools for assisting contractors in identifying their s...

Void shape changes induced by electromigration pose reliability problems in Al-based interconnects. Recent observations have shown that a rounded void sometimes collapses to a transverse slit in an interconnect with bamboo-like grain structure. This article provides a linear stability analysis for a circular void that is only partially conductive in an otherwise infinite conductive medium. The relation between the inner conductivity (i.e., the conductivity of the medium in the void) and the critical remote electric field intensity, Ecr, for the linear stability of the void is established. It is proven that when the inner conductivity becomes zero, Ecr goes to infinity, and we can look upon the inner conductivity of a vacuum void as zero. That is why the vacuum circular void is linearly stable. It is also shown that when the inner conductivity is very small, the stability of a void is sensitive to it. From the computational results, we know that if the inner conductivity is 0.1% of that outside the void, t...

A mass spectrometric method based on the combined use of fast atom bombardment collisionally-induced dissociation (CID) and tandem mass spectrometry has been used for the structural characterization of free and conjugated flavone and flavonol aglycones. Low-energy CID spectra of the [M + H]+ (or Y+0) ions show simple fragmentation patterns, which allow characterization of the substituents in the A and B rings and, in particular, differentiation between flavones and flavonols. A systematic nomenclature for product ions produced from protonated molecules under CID conditions is proposed. © 1997 John Wiley & Sons, Ltd.

The cross sections for e+e− → hadrons, e+e−, μ+μ− have been measured in the vicinity of the J Ψ resonance using the BES detector operated at BEPC. The partial widths for J Ψ to hadrons, electrons, muons and the total width have been determined to be Γh = 74.1 ± 8.1 keV, Γe = 5.14 ± 0.39 keV, Γμ = 5.13 ± 0.52 keV, and Γ = 84.4 ± 8.9 keV, respectively.

This study shows that fast atom bombardment (FAB) in combination with collisional activation and tandem mass spectrometric techniques is useful for the characterization of, and the differentiation between, O-diglycosyl, O-C- diglycosyl, and di-C-glycosyl flavonoids. A quick differentiation between the three types of glycosyl flavonoids is possible by simply examining FAB mass spectra. Low-energy product ion spectra of [M + H] + ions have been used for determining the carbohydrate sequence in O-diglycosyl flavonoids and characterizing the terminal mono-saccharide in O-C-diglycosyl flavonoids. The data obtained for per-O- deuterated precursor ion species of O-diglycosyl flavonoids indicate that O-linked hydrogen atoms are involved in the formation of Yn+ ions. High-energy product ion spectra of [M + H] + ions enable further characterization and differentiation of isomeric di-6,8-C-glycosides.

The Beijing Spectrometer (BES) is a general purpose solenoidal detector at the Beijing Electron Positron Collider (BEPC). It is designed to study exclusive final states in e + e − annihilations at the center of mass energy from 3.0 to 5.6 GeV. This requires large solid angle coverage combined with good charged particle momentum resolution, good particle identification and high photon detection efficiency at low energies. In this paper we describe the construction and the performance of BES detector.

The present study deals with the use of liquid secondary ion mass spectrometry in combination with collisionally activated dissociation and linked scanning at constant B/E for differentiation and structural analysis of 6-C- and 8-C-glycosidic flavonoids in the positive ion mode. Flavonoids of mono-C-glycosidic nature were investigated. Special emphasis is given to the rationalization of fragment ions which allow differentiation between isomers.

Existing problems in the published cross section data of the 11B(p,α) 8Be reaction and the consequences in material analysis will be reviewed. The existing cross section data on this reaction shows errors of up to 30% and inconsistency as high as 50%. New experimental data of the cross sections with the standard deviation better than 3% are presented. Application of NRA/Channeling for both the chemical concentration profiles and the carrier profiles of B implanted into silicon will be introduced. We used NRA/Channeling combined with anodic stripping to get the chemical and carrier depth profiles simultaneously. 11B(p,α) 8Be reaction at incident beam energy of 660 keV was used to probe 11B atoms. Channeling technique was applied to measure the lattice location of the 11B atoms. Anodic oxidation stripping was used to get differential depth information. This technique can deliver consistent and reliable chemical depth profiles of 11B as well as the carrier depth profiles. The differential NRA/Channeling tech...

To study the effects of extracts B1, B2, and B3 from faeces trogopterorum on the experimental gastric ulcer in rats.Two different animal models of gastric ulcers were used in this experiment: Shay's model (n = 72) and the reserpine-induced ulcer model (n = 76). The total volume and the pH of the gastric juices were recorded. The lesion scores of gastric mucosa were also recorded.The lesion scores of gastric mucosa in the Shay's model of animals in the WLZ-B1 groups treated with either 40 g/kg or 80 g/kg were 8.6 ± 10.8 and 1.6 ± 1.9 respectively, which were lower than that of the 0.9% NaCl control group (47.0 ± 31.4, P0.05, P0.01). The lesion scores for the 80 g/kg group was lower compared to those of the Ran group (20.5 ± 16.4, P0.01). The pH of the gastric juices of the 80 g/kg group (3.425 ± 0.143) was higher than that of the 0.9% NaCl group (2.836 ± 0.632, P0.05). In the reserpine model, the lesion score of the 40 g/kg group of the WLZ-B1 (20.7 ± 16.5) was also lower than that of the 0.9% NaCl control group (76.3 ± 50.6, P0.05).B1 is the most effective of the three sections in inhibiting gastric secretion, protecting gastric mucosa and preventing experimental ulceration.

A second-order strain gradient nonlocal shell model is established to study the mode transformation in single-walled carbon nanotubes (SWCNTs). Nonlocal length is calibrated carefully for SWCNTs in reference to molecular dynamics (MD) simulations through analysis of nonlocal length effects on the frequencies of the radial breathing mode (RBM) and circumferential flexural modes (CFMs) and its effects on mode transformation. All analyses show that only a negative second-order nonlocal shell model is appropriate to SWCNTs. Nonlocal length is evidently related to vibration modes and the radius-to-thickness ratio. It is found that a nonlocal length is approximately 0.1 nm in an average sense when RBM frequency is concerned. A nonlocal length of 0.122-0.259 nm is indicated for the mode transformation in a selected group of armchair SWCNTs. 2:1 and 1:1 internal resonances are found for the same SWCNT based on different models, which implies that the internal resonance mechanism depends on the model employed. Furthermore, it is shown that an effective thickness of approximately 0.1 nm is more appropriate to SWCNTs than 0.066 nm.

The hematoporphyrin derivative YHPD, a China-made product, has been clinically used in photodynamic therapy of tumors as a good photosensitizing drug. The NMR study on the structure of its major components is reported here. In terms of high performance liquid chromatography (HPLC) four major components A, B, C and D were isolated. The NMR results showed that the component A is O-acetylhematoporphyrin, B and C are two isomers of vinyldeuteroporphyrin. The spectra of 2-dimensional homonuclear correlation NMR, 2-dimensional NOE (nuclear overhauser enhancement), 13C-NMR and off-resonance as well as FAB (fast atom bombarding) mass spectrum of component D indicate that it is a protoporphyrin dimer linked by carbon-carbon bond. This finding may provide a chemical basis for understanding the difference in biological activity between YHPD and other foreign commercial HPD, as well as the composition of clinically used alkali-treated HPD and its effective component.