Engineering topics

Zhang, Haibin

Publications and source records attributed to Zhang, Haibin.

6 records

DOE OSTI2018

Pressure-induced reversible phase transition on Mo 2 Ga 2 C

The newly carbide α-Mo 2 Ga 2 C with P63/mmc space group presents a unique top-packed Ga double layer structure. Pressure-induced phase transition of Mo 2 Ga 2 C has been investigated by in-situ high-pressure synchrotron radiation X-ray diffraction, Raman spectroscopy combined with diamond anvil cell technique, and first-principle calculations. Both experimental and theoretical results show that a first-order phase transition from P6 3 /mmc to P3¯m1 occurs at ~22 GPa, where the high-pressure phase named β-Mo 2 Ga 2 C has a close-packed Ga double layer zig-zag structure. The isothermal pressure-volume relationship of Mo 2 Ga 2 C is described by the second-order Birch-Murnaghan equation of state, yielding K 0 = 139(2) GPa, K 0 ' = 4(fixed), and V 0 = 144.5(1) Å3 for α-Mo 2 Ga 2 C; K 0 = 187(3) GPa, K 0 ' = 4(fixed), and V 0 = 137.9(2) Å 3 for β-Mo 2 Ga 2 C. The instability caused by the repulsive force between the Ga atoms in the top-packed double-layer under pressure mainly accounts for the phase transition. In conclusion, the newly discovered β-Mo 2 Ga 2 C reveals that the MAX-like M 2 A 2 X type ternary compounds with different compositions may form various structures with different space groups.

58 GEOSCIENCES↗

DOE OSTI2017

Gut satiety hormones cholecystokinin and glucagon-like Peptide-1{sub 7-36} amide mediate anorexia induction by trichothecenes T-2 toxin, HT-2 toxin, diacetoxyscirpenol and neosolaniol

The food-borne trichothecene mycotoxins have been documented to cause human and animal food poisoning. Anorexia is a hallmark of the trichothecene mycotoxins-induced adverse effects. Type B trichothecenes have been previously demonstrated to elicit robust anorectic responses, and this response has been directly linked to secretion of the gut satiety hormones cholecystokinin (CCK) and glucagon-like peptide-1{sub 7–36} amide (GLP-1). However, less is known about the anorectic effects and underlying mechanisms of the type A trichothecenes, including T-2 toxin (T-2), HT-2 toxin (HT-2), diacetoxyscirpenol (DAS), neosolaniol (NEO). The purpose of this study was to relate type A trichothecenes T-2, HT-2, DAS and NEO-induced anorectic response to changes plasma concentrations of CCK and GLP-1. Following both oral gavage and intraperitoneal (IP) administration of 1 mg/kg bw T-2, HT-2, DAS and NEO evoked robust anorectic response and secretion of CCK and GLP-1. Elevations of plasma CCK markedly corresponded to anorexia induction by T-2, HT-2, DAS and NEO. Following oral exposure, plasma CCK was peaked at 6 h, 6 h, 2 h, 2 h and lasted up to 24 h, 24 h, > 6 h, > 6 h for T-2, HT-2, DAS and NEO, respectively. IP exposed to four toxins all induced elevation of CCK with peak point and duration at 6 h and > 24 h, respectively. In contrast to CCK, GLP-1 was moderately elevated by these toxins. Following both oral and IP exposure, T-2 and HT-2 evoked plasma GLP-1 elevation with peak point and duration at 2 h and 6 h, respectively. Plasma GLP-1 was peaked at 2 h and still increased at 6 h for IP and oral administration with DAS and NEO, respectively. In conclusion, CCK plays a contributory role in anorexia induction but GLP-1 might play a lesser role in this response. - Highlights: • Type A trichothecenes induce rapid and robust anorectic responses in the mouse. • Type A trichothecenes evoke elevation of gut satiety hormones CCK and GLP-1. • CCK and GLP-1 mediate anorexia induction by type A trichothecenes.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

Growth temperature-dependent metal–insulator transition of vanadium dioxide epitaxial films on perovskite strontium titanate (111) single crystals

Vanadium dioxide (VO{sub 2}) epitaxial films were grown on perovskite single-crystal strontium titanate (SrTiO{sub 3}) substrates by reactive radio-frequency magnetron sputtering. The growth temperature-dependent metal–insulator transition (MIT) behavior of the VO{sub 2} epitaxial films was then investigated. We found that the order of magnitude of resistance change across the MIT increased from 10{sup 2} to 10{sup 4} with increasing growth temperature. In contrast, the temperature of the MIT does not strongly depend on the growth temperature and is fairly stable at about 345 K. On one hand, the increasing magnitude of the MIT is attributed to the better crystallinity and thus larger grain size in the (010)-VO{sub 2}/(111)-SrTiO{sub 3} epitaxial films at elevated temperature. On the other hand, the strain states do not change in the VO{sub 2} films deposited at various temperatures, resulting in stable V-V chains and V-O bonds in the VO{sub 2} epitaxial films. The accompanied orbital occupancy near the Fermi level is also constant and thus the MIT temperatures of VO{sub 2} films deposited at various temperatures are nearly the same. This work demonstrates that high-quality VO{sub 2} can be grown on perovskite substrates, showing potential for integration into oxide heterostructures and superlattices.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2016

Lightweight graphene nanoplatelet/boron carbide composite with high EMI shielding effectiveness

Lightweight graphene nanoplatelet (GNP)/boron carbide (B{sub 4}C) composites were prepared and the effect of GNPs loading on the electromagnetic interference (EMI) shielding effectiveness (SE) has been evaluated in the X-band frequency range. Results have shown that the EMI SE of GNP/B{sub 4}C composite increases with increasing the GNPs loading. An EMI SE as high as 37 ∼ 39 dB has been achieved in composite with 5 vol% GNPs. The high EMI SE is mainly attributed to the high electrical conductivity, high dielectric loss as well as multiple reflections by aligned GNPs inside the composite. The GNP/B{sub 4}C composite is demonstrated to be promising candidate of high-temperature microwave EMI shielding material.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2016

Byzantine Reliable Broadcast in Sparse Networks

Modern large-scale networks require the ability to withstand arbitrary failures (i.e., Byzantine failures). Byzantine reliable broadcast algorithms can be used to reliably disseminate information in the presence of Byzantine failures. We design a novel Byzantine reliable broadcast protocol for loosely connected and synchronous networks. While previous such protocols all assume correct senders, our protocol is the first to handle Byzantine senders. To achieve this goal, we have developed new techniques for fault detection and fault tolerance. Our protocol is efficient, and under normal circumstances, no expensive public-key cryptographic operations are used. We implement and evaluate our protocol, demonstrating that our protocol has high throughput and is superior to the existing protocols in uncivil executions.

Byzantine broadcast↗

DOE OSTI2016

Practical State Machine Replication with Confidentiality

We study how to enable arbitrary randomized algorithms in Byzantine fault-tolerant (BFT) settings. We formalize a randomized BFT protocol and provide a simple and efficient construction that can be built on any existing BFT protocols while adding practically no overhead. We go one step further to revisit a confidential BFT protocol (Yin et al., SOSP '03). We show that their scheme is potentially susceptible to safety and confidentiality attacks. We then present a new protocol that is secure in the stronger model we formalize, by extending the idea of a randomized BFT protocol. Our protocol uses only efficient symmetric cryptography, while Yin et al.'s uses costly threshold signatures. We implemented and evaluated our protocols on microbenchmarks and real-world use cases. We show that our randomized BFT protocol is as efficient as conventional BFT protocols, and our confidential BFT protocol is two to three orders of magnitude faster than Yin et al.'s, which is less secure than ours.

Duan, Sisi↗