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Byzantine ordered consensus , introduced by Zhang et al. (OSDI 2020), is a new consensus primitive that additionally guarantees a correctness specification of transaction order, allowing nodes to assign fairly an ordering indicator to the committed transaction. Zhang et al. also presented a concrete Byzantine ordered consensus protocol called Pompē in the partially synchronous network model. However, Pompē cannot prevent an adversary from manipulating message delivery time. In this paper, we present Chronos, the first Byzantine ordered consensus protocol in the asynchronous network model, where an adversary can arbitrarily manipulate message delivery time. To construct Chronos, we propose a variant of asynchronous common subset called signal asynchronous common subset protocol, which guarantees the liveness of Chronos. We implement both Chronos and its baseline HoneyBadgerBFT using Go language and deploy them on 100 Amazon t3.medium instances distributed throughout 10 regions across the world. The experimental results show that Chronos is more efficient than HoneyBadgerBFT for small network, achieving peak throughput of 59 368 tx/s when the batch size is 100 000 and the number of nodes is 4, while the peak of HoneyBadgerBFT is 57 077 tx/s. [ABSTRACT FROM AUTHOR]

In this study, we prepared Fe74Si11B11Cr2C2 amorphous powder using the water atomization method and used a heat treatment method to simulate its aging behavior, research the effects of those different thermodynamic states on magnetic properties based XRD, DSC, and SQUID. The results indicate that in higher temperature, the exothermic peak gradually decreased from 573.7 (0.1) to 556.2(0.1) °C, and the activation energy of powder gradually decreased from 208 ± 1.3 kJ/mol to 136 ± 3.4 kJ/mol, so the thermal stability is worse. Moreover, Ms and μe of Fe74Si11B11Cr2C2 amorphous powder gradually increased; however, the frequency stability of permeability gradually decreased, and P changed from 0.93 to 3.46%. In addition, the loss rapidly increased with the increase in frequency, and X-ray diffraction was relatively insensitive to the amorphous content. [ABSTRACT FROM AUTHOR]

The microstructure, glass formation ability, and magnetic properties of Fe79Si9B6Nb5Cu1 alloy with different hydrogenation were studied. Results show that hydrogenation can improve the glass formation ability from 91.0(0.01) to 123.5(0.01) K, reduce the grain size, increase the saturation magnetization first, and then decrease, increase the coercivity. [ABSTRACT FROM AUTHOR]

• The synthesis strategy using TEAOH as a synergistic template through L zeolite transformation enabled a reduction of consumption of expensive TMAdaOH. • Pure SSZ-13 zeolites can be obtained after crystallization for only 12 h at 160 ℃. • Promoting nucleation and modulating crystal size through TEAOH auxiliary template. • The transformation mechanism of SSZ-13 from L zeolite with the assist of TEAOH is discussed. Developing an economical and high-efficiency synthesis pathway of SSZ-13 zeolite is of great significance for the ammonia selective catalytic reduction of nitrogen oxides (NH 3 -SCR of NO x) reactions. Herein, SSZ-13 zeolite were synthesized using L zeolite as the aluminum source in the presence of a mixed structure directing agent (SDA) composed of N,N,N, trimethtyl-1-adamantammonium hydroxide (TMAdaOH) and tetraethylammonium hydroxide (TEAOH). This synthesis strategy aims to accelerate the crystallization rate through interzeolite transformation, while less expensive TEAOH can play a cooperative structure-directing role, thus reducing the consumption of expensive TMAdaOH template. The results showed that pure SSZ-13 zeolites with high crystallinity can be obtained from L zeolite within 12 h at 160 ℃ under low TMAdaOH/SiO 2 ratio of 0.05 (too low to carry out the synthesis on its own in the current synthesis system) in the presence of TEAOH. Moreover, the crystallization mechanism was also investigated by XRD, FT-IR, SEM and TG-DTG techniques. It was proposed that the crystallization of SSZ-13 occurs through the formation of SSZ-13 nuclei under the direction of TMAdaOH and promotion of TEAOH, subsequently TMAdaOH was incorporated in the framework to further induce the crystal growth of SSZ-13. Especially, the zeolite crystal size can be modulated by the amount of TEAOH added. In addition, After Cu2+ exchange, the obtained Cu-SSZ-13 sample exhibits superior catalysis performance in the NH 3 -SCR of NO x reaction, and the NO x conversion rate remained over 90 % across a broad range from 200 to 600 °C, demonstrating its significant application potentials in NO x removal from diesel vehicle exhausts. [ABSTRACT FROM AUTHOR]

We prepared Fe80Si8B6Nb5Cu amorphous-nanocrystalline strips with different phosphorus addition by the melt spinning method, and their nanocrystalline magnetic powder core was obtained after a series of processing. Then, the microstructure, micromorphology, thermal behavior, and magnetic properties were studied. The results show that the atomic radius difference (σ) affected the glass formation ability; thus, first, the grain size and coercivity decreased and then increased. The (Fe80Si8B6Nb5Cu)99P nanocrystalline core has the better comprehensive magnetic properties than those of Fe80Si8B6Nb5Cu; its μe (75.93) is 5% higher, and Pcm (370 W/kg) is 14% lower than those of Fe80Si8B6Nb5Cu (i.e., 72.98 and 431.2 W/kg, respectively). [ABSTRACT FROM AUTHOR]

When an adversary can measure the physical memory storing the decryption key, decryption functionality often comes in handy. Halevi and Lin (TCC'11) studied after-the-fact (or post-challenge) leakage in public-key encryption (PKE), in which an adversary can make leakage queries from a split state after seeing the challenge ciphertext, but left security against chosen-ciphertext attacks (CCA) as a future work. In this paper, we follow their work and formulate the definition of entropic leakage-resilient CCA-secure PKE, which we show can be realized by the Naor–Yung “double encryption” paradigm (STOC'90). We then leverage it to get a CCA-secure key-encapsulation mechanism in the presence of post-challenge leakage, in the same model of bounded memory leakage from a split state. Finally, we prove that the hybrid encryption framework is still applicable by presenting a construction of CCA-secure PKE in the presence of post-challenge leakage. As additional results, we extend these concepts to the identity-based setting, where many identity-based secret-keys can be leaked after the adversary got the challenge, and give a construction of identity-based encryption in the presence of post-challenge leakage in the split-state model, which can be instantiated by the identity-based hash proof systems of Alwen et al. (Eurocrypt'10) and Chow et al. (CCS'10). [ABSTRACT FROM AUTHOR]

In this paper, we introduce a general paradigm called identity-based extractable hash proof system (IB-EHPS), which is an extension of extractable hash proof system (EHPS) proposed by Wee (CRYPTO'10). We show how to construct identity-based key encapsulation mechanism (IB-KEM) from IB-EHPS in a simple and modular fashion. Our construction provides a generic method of building and interpreting CCA-secure IB-KEMs based on computational assumptions. As instantiations, we realize IB-EHPS from the bilinear Diffie–Hellman assumption and the modified bilinear Diffie–Hellman assumption, respectively. Besides, we carefully investigate the relation between EHPS and IB-EHPS, and indicate possible refinement and generalization of EHPS. [ABSTRACT FROM PUBLISHER]

Abstract: In this paper, thick film resistors (TFRs, R8241, Heraeus) on 430 stainless steel (SS) substrate for strain sensor applications are investigated. TFRs are screen printed and fired on dielectrics-on-430SS substrate by thick film technology. Microstructure analysis shows that no interaction or evidence for new phase can be detected at the interface between TFRs and dielectrics-on-430SS, which indicates the compatibility of the dielectrics and TFRs. Further experiments also show the excellent insulativity and robust bonding between the dielectrics layer and 430SS substrate. Meanwhile, temperature coefficients of resistivity (TCRs), gauge factors (GFs) and noise indices (NI) of TFRs are measured. Finally, thick film technology based steel pressure sensors (SPS) are fabricated by screen printing and firing four TFRs on a machined circular diaphragm and then the TFRs are connected in a Wheatstone bridge configuration. Preliminary tests show that the sensors exhibit a sensitivity of 4.68mV/V full-scale (FS) with 0.1% FS linearity and 0.15% FS hysteresis and 0.15% FS repeatability. Moreover, the thermal zero drifts and thermal sensitivity drifts of the sensors in the whole temperature range (−40°C to +125°C) are less than 2.5% FS. [Copyright &y& Elsevier]

• The GFA and magnetic properties of the Fe 79 Si 9 B 4.5 P 1.5 CuNb x alloys was studied. • Nb increases the GFA but decreases the Ms, T c and grain size of the alloys. • The Fe 79 Si 9 B 4.5 P 1.5 CuNb 2 alloys exhibit the best comprehensive properties. In this study, the Fe 79 Si 9 B 4.5 P 1.5 CuNb x alloys were prepared using the melt spinning method. Further, the microstructure, micromorphology, thermal behavior, and magnetic properties of the alloys were studied. The results denote that Nb can improve the glass formation ability from 85 to 115.5 K, reduce the grain size, decrease the coercivity from 0.22 to 0.10 Oe, and rapidly decrease the Curie temperature from 705 to 648.5 K. In addition, the unit mass loss of Fe 79 Si 9 B 4.5 P 1.5 CuNb 2 is 5.84 W/kg, 19% lower than that of the Fe 79 Si 9 B 4.5 P 1.5 Cu alloys, and Ms decreased by 3%. [ABSTRACT FROM AUTHOR]

We propose an attribute-based fast data cloud-outsourcing (FDCO) scheme, which shows great performance in mobile devices. Technically, this work is a CCA-secure online/offline key encapsulation scheme based on ciphertext-policy attribute-based encryption with public validity test and indirect user revocation mechanism. We adapt it to a mobile cloud-outsourcing scenario and present a concrete system. Our scheme is equipped with the following desirable properties: First, encapsulation needs only several lightweight online modular addition/multiplication operations, which is appealing to mobile users. Second, it is equipped with an efficient indirect user revocation mechanism to support access credential revocation. Third, it supports public encapsulation validity test, which enables auditors to filter invalid data, so as to prevent attackers from sending invalid data to stuff users' accounts. Finally, we prove its security against chosen-ciphertext attacks (CCA) in the standard model. We conduct theoretical analyses and extensive experiments to show that our scheme is practical and efficient in application. [ABSTRACT FROM AUTHOR]

Identity-based non-interactive key exchange (IB-NIKE) is a powerful but a bit overlooked primitive in identity-based cryptography. While identity-based encryption and signature have been extensively investigated over the past three decades, IB-NIKE has remained largely unstudied. So far, there are only few IB-NIKE schemes in the literature. Among them, Sakai-Ohgishi-Kasahara (SOK) scheme is the first efficient and secure two-party IB-NIKE scheme, which has great influence on follow-up works. However, the SOK scheme required its identity mapping function to be modeled as a random oracle to prove security. Moreover, its existing security proof heavily relies on the ability of programming the random oracle. It is unknown whether such reliance is inherent. In this work, we intensively revisit the SOK IB-NIKE scheme and present a series of possible and impossible results in the random oracle model and the standard model. In the random oracle model, we first improve previous security analysis for the SOK IB-NIKE scheme by giving a tighter reduction. We then use meta-reduction technique to show that the SOK scheme is unlikely proven to be secure based on the computational bilinear Diffie-Hellman assumption without programming the random oracle. In the standard model, we show how to instantiate the random oracle in the SOK scheme with a concrete hash function from admissible hash functions (AHFs) and indistinguishability obfuscation. The resulting scheme is adaptively secure based on the decisional bilinear Diffie-Hellman inversion assumption. To the best of our knowledge, this is the first adaptively secure IB-NIKE scheme in the standard model that does not explicitly require multilinear maps. Previous schemes in the standard model either have merely selective security or require programmable hash functions from multilinear maps. At the technical heart of our scheme, we generalize the definition of AHFs and propose a generic construction which enables AHFs with previously unachieved parameters. This might be of independent interest. In addition, we present some new results about IB-NIKE. Firstly, we propose a generic construction of multiparty IB-NIKE from extractable witness PRFs and existentially unforgeable signatures. Secondly, we investigate the relation between semi-adaptive security and adaptive security of IB-NIKE. Somewhat surprisingly, we show that these two notions are polynomially equivalent. [ABSTRACT FROM AUTHOR]

Tailoring the electrode structure and morphology with short diffusion distance for fast ions transport is of significant to improve rate capability for advanced lithium-ion batteries. A novel architecture of hollow Co 3 O 4 nanocrystals in situ anchored on holey graphene is successfully fabricated, and individual hollow Co 3 O 4 nanocrystal is located around one etched hole on graphene sheets. This newly fabricated nanostructure is able to greatly shorten mass diffusion distance for enhancement of Li ion transport, resulting in the best rate performance among previously reported composites of Co 3 O 4 and graphene. This work reveals that high rate lithium-ion batteries can be achieved through constructing the hybrids of Co 3 O 4 nanocrystals on in situ etched holey graphene, while rendering fundamental for enhancement of mass transport rate by highly shortened ions diffusion distance in a nanostructured electrode to accomplish superior rate capability. Image 1 [ABSTRACT FROM AUTHOR]

We first developed NdFeB/PrCo5 nanocomposite magnetic material by high-energy ball milling, and the influence of the different contents of PrCo5 on the magnetic properties of NdFeB was studied by means of XRD, DSC, and VSM. The results showed that compared with single-phase NdFeB permanent-magnet material, NdFeB/PrCo5 nanocomposite magnetic material has superior magnetic properties. When the content of PrCo5 is 10% and the time of ball milling is 10 h, the magnetic properties for NdFeB/PrCo5 nanocomposite magnetic material is best: coercivity is 13.2 kOe, which increased by 14.8% over pure NdFeB phase. Remanent magnetization is 96.31 emu/g and the saturation magnetization is 132.29 emu/g. The remanence ratio is 0.728. [ABSTRACT FROM AUTHOR]

M-type hexagonal ferrites (SrFe 12 O 19) have attracted much attention as a widely used permanent magnet. Many studies have been done to improve permanent magnetic properties. In particular, the formula of La–Co co-replaced Sr–Fe has achieved higher performance. However, no one has studied the influence of a small amount of Al ions on the above formula. In this study, the Al3+ ion substituted M-type Sr 0.7 La 0.3 Fe 11.75ￚ x Al x Co 0.25 O 19 (0 ​≤ ​ x ​≤ ​0.12) hexagonal ferrites were synthesized by solid state reaction. The crystalline structure was investigated by using X-ray diffraction (XRD) and the Rietveld refining method. The morphological of powder and magnetically oriented bulk were observed by scanning electron microscopy (SEM), and magnetic properties were measured by physical property measurement system-vibrating sample magnetometer (PPMS-VSM) techniques. The results show that a single M-type strontium ferrite was obtained with the Aluminum (Al) content (x) from 0 to 0.08, and the impure phase appeared when x was 0.12. The lattice parameters a and c both decreased with the increasing Al3+ content. SEM images indicate the hexagonal platelet-like particles and the size of the magnetic powders about 2–5 ​μm, and the powders are easily arranged in one direction under a magnetic field. The saturation magnetization (M s) of the hexaferrite decreased with the increase of x from 0 to 0.12, but coercivity (H c) of the magnetic powders increased with Al3+ content (x) from 0 to 0.12. After magnetic field orientation, the XRD pattern and micro-morphology of the magnet were changed. [Display omitted] • The powders are easily arranged in one direction under a magnetic field. • The lattice parameters a and c both decreased with the increasing Al3+ content. • The coercivity (H c) of the magnetic powders increased with Al3+ content. [ABSTRACT FROM AUTHOR]

In recent years, natural draft dry cooling systems with only one tower have been adopted in some 2 × 660 MW power-generating units owing to the advantage of lower construction costs. The operating cases of two power-generating units and one power-generating unit will both appear based on the power load requirement, which may lead to very different flow and heat transfer performances of this typical cooling system. Therefore, this research explores the local thermo-flow characteristics of air-cooled heat exchangers and sectors, and then analyzes the overall cooling performance of the above two operating cases under various wind conditions. Using the numerical modeling method, the results indicate that the flow and heat transfer performance of this cooling system decreases significantly in the case of one unit with half sectors dismissed. At wind speeds lower than 8 m/s, the difference in turbine back pressure between two units and one unit appears obviously higher than in other wind conditions, even reaching 4.37 kPa. Furthermore, the air-cooled heat exchanger in the lower layer always has better cooling capability than that in the upper layer, especially in conditions where there is an absence of wind and under low wind speeds. The operating case of one unit is not recommended for this dry cooling system because of the highly decreased energy efficiency. In conclusion, this research could provide theoretical support for the engineering operation of this typical natural draft dry cooling system in 2 × 660 MW power plants. [ABSTRACT FROM AUTHOR]