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The purpose of this paper is to make an assessment on the performance of an FRP helmet-head system subjected to ballistic impact. Firstly, an FE model for human head is developed in which it mainly consists of scalp, skull, meanings, cerebrospinal fluid, brain tissue, falx, tentorium, face and neck. Constitutive models for each component of the head are determined and, in particular, strain rate effects of the compact bone of skull and the hyperelastic property of scalp are taken into account for the first time. Secondly, an FE model for Kevlar fibre reinforced phenolic helmet are constructed based on PASGT helmet. Recently developed dynamic constitutive models for metals and FRP laminates are employed for FMJ bullet and the KFRP helmet, respectively in the present study. Finally, both the head and helmet models are validated against available test data. Furthermore, effects of padding system (strap-netting and OA foam), impact position (top, front, lateral and rear), and projectile type (FSP and FMJ) on the ballistic performance of the helmet-head system have been systematically investigated with special attention being paid to the severity of head injury. It is found that the performance of the helmet with OA foam is advantageous over that of the helmet with strap-netting in head injury prevention; that the most harmful impact positions are different for helmets with different liner systems. It is also found that a lower velocity (358m/s) FMJ bullet pose more threats to head injury than a higher velocity (610m/s) FSP for the PASGT helmet-head system.

The elementary excitation spectrum of a two-component Bose–Einstein condensate is obtained by Green’s function method. It is found to have two branches. In the long-wave limit, the two branches of the excitation spectrum are reduced to one phonon excitation and one single-particle excitation. With the obtained excitation spectrum and the Green’s functions, the depletion of the condensate and the ground state energy have also been calculated in this paper.

The dynamics of the Josephson effects for a homogeneous two-component Bose-Einstein condensate in different hyperfine states is studied by two coupled nonlinear equations, which are obtained by mean field approximation. We have shown the nonlinear Josephson effects, including Plasmon and macroscopic self-trapping. We have also studied the relaxation dynamics and the system under damping will evolve into a stationary state of two equivalent components. For the equivalent two-component condensate, Green’s function method is applied to find the excitation spectrum. We found that the excitation spectrum has two branched, of which one is the phonon excitation and one is of the single-particle form in the long wave-length limit. We have also studied the depletion of the condensate in the ground state.

Fiber reinforced plastic laminates (FRP) have been increasingly used in various engineering such as aeronautics, astronautics, transportation, naval architecture and their impact response and failure are a major concern in academic community. A new numerical model is suggested for fiber reinforced plastic composites. The model considers that FRP laminates has been constituted by unidirectional laminated plates with adhesive layers. A modified adhesive layer damage model that considering strain rate effects is incorporated into the ABAQUS / EXPLICIT finite element program by the user-defined material subroutine VUMAT. It transpires that the present model predicted delamination is in good agreement with the experimental results for low velocity impact.

An approximate quasi-static theory is developed to predict large plastic deformation and perforation of spherical shells subjected to impact by blunt-ended projectiles at normal incidence. Based on experimental observations for quasi-static load-displacement characteristics, the problem of a spherical shell under normal impact by a flat-ended missile may be analyzed through the solutions to that of an equivalent circular plate struck transversely by the same missile. It is shown that the approximate theoretical predictions with a = 30 (here a is an empirical constant) are in good agreement with experimental data, in terms of maximum permanent transverse displacements and dimple radii. Furthermore, a theoretical formula for ballistic limits of spherical shells under missile impact is presented and the range of applicability of the theory is discussed.

Liguzinediol (LZDO) could mediate the positive inotropic effects through sarcoplasmic reticulum Ca2+ ATPase-dependent mechanism without the risk of arrhythmia. However, the pharmacophore of LZDO contributed to the activities was not clear. The aim of this work was to explore the relationship between positive inotropic effect and scaffold of LZDO as well as to check whether the pharmacophore of LZDO on anti-heart failure activity was located at the pyrazine ring. A series of LZDO analogs (3a-b, 4a-b, 9-19) were designed and synthesised, and their activities were evaluated on isolated heart contractility by Langendorff perfusion. The results showed that the efficacy of LZDO was reduced when the hydroxyl, carboxyl or ester moieties at the side chain position of LZDO were induced, and the para-dihydroxy in LZDO was necessary for its activity. Thus, the pharmacophore of the positive inotropic effect might be located at the whole scaffold of LZDO, but not at the pyrazine ring. The finding may provide an important clue of the pharmacophore for the development of novel cardiotonic agents.

Multiple acute cerebral infarcts (MACIs) detected by diffusion-weighted imaging (DWI) may indicate an unstable source of thromboembolism. The authors studied 119 consecutive acute ischemic stroke patients within 24 hours of onset with DWI. MACIs were present in 20 patients (16.8%). During the follow-up period, there were 15 recurrent strokes, 3 acute coronary syndromes, and 5 deaths. MACI was the only significant independent predictor for vascular events and death (odd ratio [OR]] = 4.34; p = 0.001) and stroke recurrence (OR = 5.93; p = 0.001).

An experimental investigation is reported on the dynamic response of a clamped circular plate struck transversely by a mass at any point along a radial line. A study is made of the variation of the failure mode with a change of striker diameter-plate thickness ratio, together with an assessment of transverse shear effects and the energy-absorbing capacity for impact velocities up to 12.2 m/s. The experimental results show that the steel and aluminium alloy targets fail by plugging with a plug having approximately the same diameter as the striker, which has a blunt end. The experimental results also show that the energy-absorbing capacity of a plate is reduced significantly when struck by a mass close to the supports compared to a strike at the centre and that the transverse shear force plays a more dominant role when a mass strikes close to the supports. A new criterion for the design of metal targets against projectile impact is proposed.

The relationship between the apolipoprotein E (APOE) exon 4 polymorphism and white matter changes (WMC) in elderly subjects or patients with Alzheimer's disease is controversial. To investigate this polymorphism in relation to WMC in patients with lacunar infarcts, we prospectively observed 67 patients with acute lacunar infarct and 134 age- and sex-matched controls. Genotypes were determined using a nested polymerase chain reaction. WMC were measured quantitatively and were divided into two groups, severe and mild, with the mean volume of WMC as the cut point. Twenty-two patients (33%) had severe WMC. There was a significant difference in the distribution of APOE epsilon2, epsilon3, and epsilon4 alleles between severe and mild WMC groups (P = 0.002). The frequency of epsilon4 alleles was higher in patients with severe WMC than in those with mild WMC (25% vs. 7%, P = 0.003). These results suggest that APOE epsilon4 may exacerbate WMC in patients with lacunar infarcts. Further studies are required to confirm this finding.

The process and performance of High Temperature Superconducting Current Leads whose current up to l000A were introduced. The HTS leads were made of Bi-2223 rods by a multiple process of cold-isostatic press (MCIP) and heat treatments. The transport currents were measured by a standard four-probe DC method. The results showed the current over l000A at 77K and 0T, and 500A at 77K and 0.1T.