Strong Gravitational Lensing of Gravitational Waves with TianQin

When gravitational waves pass by a massive object on its way to the Earth, strong gravitational lensing effect will happen. Thus the GW signal will be amplified, deflected, and delayed in time. Through analysing the lensed GW waveform, physical properties of the lens can be inferred. On the other hand, neglecting lensing effects in the analysis of GW data may induce systematic errors in the estimating of source parameters. As a space-borne GW detector, TianQin will be launched in the 2030s. It is expected to detect dozens of MBHBs merger as far as z = 15, and thus will have high probability to detect at least one lensed event during the mission lifetime. In this article, we discuss the capability of TianQin to detect lensed MBHBs signals. Three lens models are considered in this work: the point mass model, the SIS model, and the NFW model. The sensitive frequency band for space-borne GW detectors is around milli-hertz, and the corresponding GW wavelength could be comparable to the lens gravitational length scale, which requires us to account for wave diffraction effects. In calculating lensed waveforms, we adopt the approximation of geometric optics at high frequencies to accelerate computation, while precisely evaluate the diffraction integral at low frequencies. Through a Fisher analysis, we analyse the accuracy to estimate the lens parameters. We find that the accuracy can reach to the level of 10^-3 for the mass of point mass and SIS lens, and to the level of 10^-5 for the density of NFW lens. We also assess the impact on the accurate of estimating the source parameters, and find that the improvement of the accuracy is dominated by the increasing of SNR.Comment: 12 pages, 8 figure

Identification of critical residues of influenza neuraminidase in viral particle release

BACKGROUND: Influenza neuraminidase (NA) is essential for virus release from its host cells and it is one of the targets for structure-based antiviral drug design. RESULTS: In this report, we established a pseudoviral particle release assay to study NA function, which is based on lentiviral particles pseudotyped with influenza glycoproteins HA and NA as a surrogate system. Through an extensive molecular analysis, we sought to characterize important residues governing NA function. We identified five residues of NA, 234, 241, 257, 286 and 345, four of which (except 345) map away from the active site of NA when projected onto the three-dimensional structure of avian influenza H5N1 NA, and substitutions of these residues adversely affected the NA-mediated viral particle release, suggesting that these residues are critical for NA enzymatic activity. CONCLUSION: Through extensive chimeric and mutational analyses, we have identified several residues, which map away from the active site and are critical for NA function. These findings provide new insights into NA-mediated pseudoviral particle release and may have important implications in drug design and therapeutics against influenza infection

Study on Spinnability of PP/PU Blends and Preparation of PP/PU Bi-component Melt Blown Nonwovens

Melt blown polymer blends offers a good way to combine two polymers in the same fiber generating nonwovens with new and novel properties. In this study, polypropylene (PP) and polyurethane (PU) were blended to prepare PP/PU bicomponent melt blown nonwovens. The spinnability of PP/PU composites was investigated and PP/PU bi-component nonwovens with compositions of 95/5, 90/10, 80/20 and 70/30 were prepared by using the melt blowing technique. The melt blown fibers exhibited a ‘sea-island’ structure with PP as the continuous phase and PU as the dispersed phase. When the content of PU in the blend was above 40 %, PP/PU melt blown nonwovens could not be produced due to fiber breaking. For PP/PU (90/10) nonwovens, it was found that the average fiber diameter decreased with increasing die to collector (DCD) and elevated hot air pressure

Strategies for Exploring Functions from Dynamic Combinatorial Libraries

Dynamic combinatorial chemistry (DCC) is a powerful approach for creating complex chemical systems, giving access to the studies of complexity and exploration of functionality in synthetic systems. However, compared with more advanced living systems, the man‐made chemical systems are still less functional, due to their limited complexity and insufficient kinetic control. Here we start by introducing strategies to enrich the complexity of dynamic combinatorial libraries (DCLs) for exploiting unexpected functions by increasing the species of building blocks and/or templates used. Then, we discuss how dynamic isomerization of photo‐switchable molecules help DCLs increase and alter the systemic complexity in‐situ. Multi‐phase DCLs will also be reviewed to thrive complexity and functionality across the interfaces. Finally, there will be a summary and outlook about remote kinetic control in DCLs that are realized by applying exogenous physical transduction signals of stress, light, heat and ultrasound.</p

A New Method to Analyze the Security of Protocol Implementations Based on Ideal Trace

The security analysis of protocols on theory level cannot guarantee the security of protocol implementations. To solve this problem, researchers have done a lot, and many achievements have been reached in this field, such as model extraction and code generation. However, the existing methods do not take the security of protocol implementations into account. In this paper, we have proposed to exploit the traces of function return values to analyze the security of protocol implementations at the source code level. Taking classic protocols into consideration, for example (like the Needham-Schroeder protocol and the Diffie-Hellman protocol, which cannot resist man-in-the-middle attacks), we have analyzed man-in-the-middle attacks during the protocol implementations and have carried out experiments. It has been shown in the experiments that our new method works well. Different from other methods of analyzing the security of protocol implementations in the literatures, our new method can avoid some flaws of program languages (like C language memory access, pointer analysis, etc.) and dynamically analyze the security of protocol implementations