Pure Even Harmonic Generation from Oriented CO in Linearly Polarized Laser Fields

The first high harmonic spectrum, containing only the odd orders, was observed in experiments 30 years ago (1987). However, a spectrum containing pure even harmonics has never been observed. We investigate the generation of pure even harmonics from oriented CO molecules in linearly polarized laser fields employing the time-dependent density-functional theory. We find that the even harmonics, with no odd orders, are generated with the polarization perpendicular to the laser polarization, when the molecular axis of CO is perpendicular to the laser polarization. Generation of pure even harmonics reveals a type of dipole acceleration originating from the permanent dipole moment. This phenomenon exists in all system with permanent dipole moments, including bulk crystal and polyatomic molecules

Study on influence factors of underwater shockwave sensor dynamic calibration

To test coefficient sensitivity of underwater shockwave pressure sensor, dynamic calibration is conducted using traceable standard bench sensor and PCB913B02 sensor calibration equipment. In the research, silicon oil of different specification was filled into sealed tank in order to study the relations between silicon oil specification and calibration result of pressure sensor. Explosion tests are conducted using explosives of different formulas and underwater shockwave sensors filled with silicon oils of different specifications. The test result shows such principle and the method of calibration mentioned above could ensure the calibration precision, which therefore certifies the accuracy of shockwave pressure test

Low Temperature Epitaxial Growth of High Permittivity Rutile TiO2TiO_2 on SnO2SnO_2

Thin films of high dielectric constant $\kappa \sim 68$ rutile phase titanium dioxide $TiO_2$ were grown epitaxially on tin dioxide $SnO_2$ substrates, which are a low cost, more abundant alternative to ruthenium electrodes used previously. Atomic layer deposition at low temperature ${250^\circ C}$ was used with titanium(IV) tetrakis(isopropoxide) and hydrogen peroxide $H_2O_2$ as precursors. The rutile $TiO_2$ thin films have crystalline grains that match the structure and orientation of the grains in the polycrystalline rutile phase $SnO_2$ substrates. The epitaxial relations can be clearly identified from the continuous lattice fringes across the interfaces.Chemistry and Chemical BiologyOther Research Uni

Direct detonation initiation in hydrogen/air mixture: effects of compositional gradient and hotspot condition

Two-dimensional simulations are conducted to investigate the direct initiation of cylindrical detonation in hydrogen/air mixtures with detailed chemistry. The effects of hotspot condition and mixture composition gradient on detonation initiation are studied. Different hotspot pressure and composition are first considered in the uniform mixture. It is found that detonation initiation fails for low hotspot pressures and supercritical regime dominates with high hotspot pressures. Detonation is directly initiated from the reactive hotspot, whilst it is ignited somewhere beyond the nonreactive hotspots. Two cell diverging patterns (i.e., abrupt and gradual) are identified and the detailed mechanisms are analyzed. Moreover, cell coalescence occurs if many irregular cells are generated initially, which promotes the local cell growing. We also consider nonuniform detonable mixtures. The results show that the initiated detonation experiences self-sustaining propagation, highly unstable propagation, and extinction in mixtures with a linearly decreasing equivalence ratio along the radial direction respectively, i.e., 1 to 0.9, 1 to 0.5 and 1 to 0. Moreover, the hydrodynamic structure analysis shows that, for the self-sustaining detonations, the hydrodynamic thickness increases at the overdriven stage, decreases as the cells are generated, and eventually become almost constant at the cell diverging stage, within which the sonic plane shows a sawtooth pattern. However, in the detonation extinction cases, the hydrodynamic thickness continuously increases, and no sawtooth sonic plane can be observed

Effects of selenium adaptation on intestinal morphology, antioxidant-relate genes expression and intestinal microflora of grass carp (Ctenopharyngodon idella)

In the study, the effects of selenium on intestinal tissue morphology, antioxidant-related genes, and intestinal flora of grass carp (Ctenopharyngodon idella) were studied. For this purpose, 180 healthy grass carps (20.0±2.0 g) were randomly divided into three groups with three replicates each: the corresponding amount of anhydrous sodium selenite was added to make experimental water solutions of different concentrations, including 0 μg/L Se4+ (control group), 200 μg/L Se4+ group and 300 μg/L Se4+ group. The experiment was carried out for 42 days. The obtained results showed that: at the end of the experiment, the 200 μg/L Se4+ adaptation can have beneficial effects on the intestinal villi height and goblet cells. The CuZnSOD and CAT genes mRNA levels of grass carp intestine were strongly upregulated in the 200ug/L Se4+ group. 200ug/L selenium could increase the expression level of the Hsp70 gene in the intestinal tract of grass carp after 42 days of adaptation. At the genus level, the most abundant sequence in the gut of Se-treated grass carp was Pseudomonas, while Aeromon, Flavobacterium, and Defluviimonas were more abundant in the control group. In conclusion, this study demonstrates that 200ug/L Se4+ selenium adaptation can positively affect gut morphology and antioxidant responses and can alter the gut microbiota structure of grass carp. The results will provide a theoretical basis for further research on the effect of selenium on aquatic animals

Dynamic Shock Cushioning Characteristics and Vibration Transmissibility of X-PLY Corrugated Paperboard

X-PLY corrugated paperboard is a new-type corrugated paperboard with three layers of orthotropic corrugated sandwiches structure, and may be employed to protect products from shock or vibration damage during distribution. This article deals with the characterization of properties of X-PLY corrugated paperboard relevant to its application for protective packaging in distribution, such as dynamic cushioning curves, vibration transmissibility and frequency curves. The main feature of article is the evaluation on the dynamic shock cushioning characteristics and vibration transmissibility of X-PLY corrugated paperboards by a series of experimental studies on the drop shock tester and vibration tester, the establishment of experimental formulas of dynamic cushioning curves, and the analysis of peak frequencies, vibration transmissibility and damping ratios. By using the fitting polynomial of curve and method of the least mean square, the experimental formulas and characteristic coefficients of dynamic cushioning curves have been obtained. From the vibration tests with slow sine sweep, the peak frequencies and vibration transmissibility are measured and used to estimate the damping ratios. These works provide basic data and curves relevant to its application for protective packaging in distribution

Dual-terminal event triggered control for cyber-physical systems under false data injection attacks

summary:This paper deals with the problem of security-based dynamic output feedback control of cyber-physical systems (CPSs) with the dual-terminal event triggered mechanisms (DT-ETM) under false data injection (FDI) attacks. Considering the limited attack energy, FDI attacks taking place in transmission channels are modeled as extra bounded disturbances for the resulting closed-loop system, thus enabling $H_{\infty}$ performance analysis with a suitable $\varrho$ attenuation level. Then two buffers at the controller and actuator sides are skillfully introduced to cope with the different transmission delays in such a way to facilitate the subsequent security analysis. Next, a dynamic output feedback security control (DOFSC) model based on the DT-ETM schemes under FDI attacks is well constructed. Furthermore, novel criteria for stability analysis and robust stabilization are carefully derived by exploiting Lyapunov-Krasovskii theory and LMIs technique. Finally, an illustrative example is provided to show the effectiveness of the proposed method

MicroRNA-26a-mediated regulation of interleukin-2 expression in transformed avian lymphocyte lines

<p>Abstract</p> <p>Background</p> <p>Micro(mi)RNAs are a class of small non-coding RNAs that play critical roles in the induction of various cancers, including lymphomas induced by oncogenic viruses. While some of the miRNAs are oncogenic, miRNAs such as miR-26a are consistently downregulated in a number of cancers, demonstrating their potential tumor suppressor functions. Global miRNA expression profiles of a number of virus-transformed avian lymphoma cell lines have shown downregulation of gga-miR-26a expression, irrespective of molecular mechanisms of transformation or the viral aetiology. The neoplastic transformation of lymphocytes by many viruses accompanies high levels of proliferative responses, mostly mediated through cytokines such as IL-2. Chicken IL-2 can modulate T-cell proliferation and cytotoxicity <it>in vitro </it>and <it>in vivo </it>and dysregulation of IL-2 expression is observed in diseases such as leukaemia.</p> <p>Results</p> <p>The expression levels of gga-miR-26a in chicken lymphoma cells transformed by 3 distinct avian oncogenic viruses, <it>viz </it>Marek's disease virus (MDV), avian leukosis virus (ALV) and Reticuloendotheliosis virus (REV) were consistently downregulated compared to the levels in the normal lymphocytes. This downregulation of miR-26a regardless of the viral etiology and molecular mechanisms of transformation was consistent with the tumor suppressor role of this miRNA. Notwithstanding this well-established role in cancer, we demonstrate the additional role of this miRNA in directly targeting chicken IL-2 through reporter and biochemical assays. The downregulation of miR-26a can relieve the suppressive effect of this miRNA on IL-2 expression.</p> <p>Conclusions</p> <p>We show that miR-26a is globally downregulated in a number of avian lymphoma cells irrespective of the mechanisms of transformation, reiterating the highly conserved tumor suppressor function of this miRNA. However, with the potential for directly targeting chicken IL-2, the downregulation of miR-26a in these tumor cells could relieve the inhibitory effect on IL-2 expression assisting in the proliferative features of the transformed lymphocyte lines.</p