Structural Transitions of Amorphous Alloys under High Pressure

An attempt is made in this paper to cover the results of the recent experimental investigations on the effects of high pressure on the crystallization of amorphous Fe-17at.% B, Nb-19at.% Si and Pd-20at.% Si alloys. Pressure is shown to raise appreciably the onset temperature of crystallization and change the structural sequence of crystalline phases forming in the alloys. The phases preferentially forming are the DO_e-type Fe_3B, Al5-type Nb_3Si and bct Si-rich phase. The structural characteristics of these transformations are discussed in the light of the knowledge of atomic structure of the amorphous alloys

Android HIV: A Study of Repackaging Malware for Evading Machine-Learning Detection

Machine learning based solutions have been successfully employed for automatic detection of malware in Android applications. However, machine learning models are known to lack robustness against inputs crafted by an adversary. So far, the adversarial examples can only deceive Android malware detectors that rely on syntactic features, and the perturbations can only be implemented by simply modifying Android manifest. While recent Android malware detectors rely more on semantic features from Dalvik bytecode rather than manifest, existing attacking/defending methods are no longer effective. In this paper, we introduce a new highly-effective attack that generates adversarial examples of Android malware and evades being detected by the current models. To this end, we propose a method of applying optimal perturbations onto Android APK using a substitute model. Based on the transferability concept, the perturbations that successfully deceive the substitute model are likely to deceive the original models as well. We develop an automated tool to generate the adversarial examples without human intervention to apply the attacks. In contrast to existing works, the adversarial examples crafted by our method can also deceive recent machine learning based detectors that rely on semantic features such as control-flow-graph. The perturbations can also be implemented directly onto APK's Dalvik bytecode rather than Android manifest to evade from recent detectors. We evaluated the proposed manipulation methods for adversarial examples by using the same datasets that Drebin and MaMadroid (5879 malware samples) used. Our results show that, the malware detection rates decreased from 96% to 1% in MaMaDroid, and from 97% to 1% in Drebin, with just a small distortion generated by our adversarial examples manipulation method.Comment: 15 pages, 11 figure

3,3′-Dibromo-1,1′-[ethyl­enedioxy­bis(nitrilo­methyl­idyne)]dibenzene

In the centrosymmetric title compound, C16H14Br2N2O2, the intra­molecular interplanar distance between the parallel benzene rings is 1.305 (3) Å, while the inter­molecular interplanar distance (between neighbouring mol­ecules) is 3.463 (3) Å, exhibiting obvious strong inter­molecular π–π stacking inter­actions

1,3-Bis[(4-nitro­benzyl­idene)amino­oxy]propane

The complete molecule of title compound, C17H16N4O6, is generated by a crystallographic twofold axis. Within the mol­ecule, the two benzene units are approximately perpen­dicular, making a dihedral angle of 85.91 (4)°. In the crystal, mol­ecules are linked into a three-dimensional network by C—H⋯O hydrogen bonds and short O⋯O and N⋯O inter­actions, with distances of 2.998 (2) and 2.968 (3) Å, respectively

Bis{(E)-2-[(2-chloro-3-pyrid­yl)imino­meth­yl]-6-meth­oxy­phenolato-κ2 N,O 1}copper(II)

In the title mononuclear copper(II) complex, [Cu(C13H10ClN2O2)2], the CuII ion, lying on an inversion center, is four-coordinated in a trans-CuN2O2 square-planar geometry by two phenolate O and two imino N atoms from two symmetry-related N,O-bidentate Schiff base ligands. The shortest Cu⋯Cu distance is 7.5743 (9) Å. However, there are weak intra­molecular electrostatic inter­actions between the Cu atom and the Cl atom of the ligand, with a Cu⋯Cl distance of 3.3845 (9) Å

Motor Vehicle Emission Modeling and Software Simulation Computing for Roundabout in Urban City

In urban road traffic systems, roundabout is considered as one of the core traffic bottlenecks, which are also a core impact of vehicle emission and city environment. In this paper, we proposed a transport control and management method for solving traffic jam and reducing emission in roundabout. The platform of motor vehicle testing system and VSP-based emission model was established firstly. By using the topology chart of the roundabout and microsimulation software, we calculated the instantaneous emission rates of different vehicle and total vehicle emissions. We argued that Integration-Model, combing traffic simulation and vehicle emission, can be performed to calculate the instantaneous emission rates of different vehicle and total vehicle emissions at the roundabout. By contrasting the exhaust emissions result between no signal control and signal control in this area at the rush hour, it draws a conclusion that setting the optimizing signal control can effectively reduce the regional vehicle emission. The proposed approach has been submitted to a simulation and experiment that involved an environmental assessment in Satellite Square, a roundabout in medium city located in China. It has been verified that setting signal control with knowledge engineering and Integration-Model is a practical way for solving the traffic jams and environmental pollution

Statistical Properties of X-Ray Bursts from SGR J1935+2154 Detected by Insight-HXMT

As one class of the most important objects in the universe, magnetars can produce a lot of different frequency bursts including X-ray bursts. In \cite{2022ApJS..260...24C}, 75 X-ray bursts produced by magnetar SGR J1935+2154 during an active period in 2020 are published, including the duration and net photon counts of each burst, and waiting time based on the trigger time difference. In this paper, we utilize the power-law model, $dN(x)/dx\propto (x+x_0)^{-\alpha_x}$, to fit the cumulative distributions of these parameters. It can be found that all the cumulative distributions can be well fitted, which can be interpreted by a self-organizing criticality theory. Furthermore, we check whether this phenomenon still exist in different energy bands and find that there is no obvious evolution. These findings further confirm that the X-ray bursts from magnetars are likely to be generated by some self-organizing critical process, which can be explained by a possible magnetic reconnection scenario in magnetars.Comment: 6 pages, 1 figure and 3 tables; published in Research in Astronomy and Astrophysic

Modular assembly for multicell structures with designable energy absorption characteristics

In this study, a novel modular multicell structure was proposed to achieve tunable energy absorption characteristics. Dovetail grooves and protrusions were designed on square thin-walled tubes as interfaces to realize the modular assembly. The quasi-static compression experimental results showed that single thin-walled tubes made of thermoplastic polyurethanes and short carbon-fiber-reinforced polyamide exhibited high elasticity and high compressive strength, respectively. Due to the different mechanical properties of the two materials, energy absorption performance of modular structures reached different levels with the variation of cell materials. The concept of modular multicell structure provided possibility to customize energy absorbers with desired properties