Atomic Layer Deposition of Buffer Layers for the Growth of Vertically Aligned Carbon Nanotube Arrays

Vertically aligned carbon nanotube arrays (VACNTs) show a great potential for various applications, such as thermal interface materials (TIMs). Besides the thermally oxidized SiO 2 , atomic layer deposition (ALD) was also used to synthesize oxide buffer layers before the deposition of the catalyst, such as Al 2 O 3 , TiO 2 , and ZnO. The growth of VACNTs was found to be largely dependent on different oxide buffer layers, which generally prevented the diffusion of the catalyst into the substrate. Among them, the thickest and densest VACNTs could be achieved on Al 2 O 3 , and carbon nanotubes were mostly triple-walled. Besides, the deposition temperature was critical to the growth of VACNTs on Al 2 O 3 , and their growth rate obviously reduced above 650 \ub0C, which might be related to the Ostwald ripening of the catalyst nanoparticles or subsurface diffusion of the catalyst. Furthermore, the VACNTs/graphene composite film was prepared as the thermal interface material. The VACNTs and graphene were proved to be the effective vertical and transverse heat transfer pathways in it, respectively

Genomic monitoring of SARS-CoV-2 uncovers an Nsp1 deletion variant that modulates type I interferon response

The SARS-CoV-2 virus, the causative agent of COVID-19, is undergoing constant mutation. Here, we utilized an integrative approach combining epidemiology, virus genome sequencing, clinical phenotyping, and experimental validation to locate mutations of clinical importance. We identified 35 recurrent variants, some of which are associated with clinical phenotypes related to severity. One variant, containing a deletion in the Nsp1-coding region (D500-532), was found in more than 20% of our sequenced samples and associates with higher RT-PCR cycle thresholds and lower serum IFN-beta levels of infected patients. Deletion variants in this locus were found in 37 countries worldwide, and viruses isolated from clinical samples or engineered by reverse genetics with related deletions in Nsp1 also induce lower IFN-beta responses in infected Calu-3 cells. Taken together, our virologic surveillance characterizes recurrent genetic diversity and identified mutations in Nsp1 of biological and clinical importance, which collectively may aid molecular diagnostics and drug design.Peer reviewe

Characteristic analysis of deep water gravity flow sediments in Ch6-Ch7 Section of Yanchang Formation in the Binchang Block, southern Ordos Basin, China

Massive sandstone without sedimentary structure is developed in the Ch6-Ch7 Section of Yanchang Formation in the Binchang Block, Southern Ordos Basin, which has a good oil and gas show, good productivities and good exploration and development prospect. However, the formation mechanism of the sandstone is still in dispute. It is of great significance to determine the sedimentary facies and sedimentary model of the sandstone in Ch6-Ch7 Section in order to analyze the formation mechanism of sweet spot in the low permeability sandstone reservoirs, to predict the sweet spot distribution model and guide the subsequent exploration and development. In this paper, 15 lithofacies and 3 main types of sedimentary microfacies, namely, sandy debris flow, turbidite and seismite slump microfacies, have been identified by using a large amount of core sedimentary description data, grain size analysis data and geological mapping analysis, and these three kinds of sedimentary assemblies in space. The deep water gravity flow deposition model in the Ch6-Ch7 Section can be summarized as the sublacustrine fan model and can be divided into three subfacies or assemblies: the upper fan subfacies dominated by the assembly of seismite-slump and sandy debris flow, the mid-fan subfacies dominated by the assembly of the sand debris flow-turbidite microfacies and the lower-fan subfacies dominated by turbidite flow-basin plain microfacies assembly

Chaotic binary sensing matrices

As an emerging field for sampling paradigms, compressive sensing (CS) can sample and represent signals at a sub-Shannon-Nyquist rate. To realize CS from theory to practice, the random sensing matrices must be substituted by faster measurement operators that correspond to feasible hardware architectures. In recent years, binary matrices have attracted much research interest because of their multiplier-less and faster data acquisition. In this work, we aim to pinpoint the potential of chaotic binary sequences for constructing high-efficiency sensing implementations. In particular, the proposed chaotic binary sensing matrices are verified to meet near-optimal theoretical guarantees in terms of both the restricted isometry condition and coherence analysis. Simulation results illustrate that the proposed chaotic constructions have considerable sampling efficiency comparable to that of the random counterparts. Our framework encompasses many families of binary sensing architectures, including those formed from Logistic, Chebyshev, and Bernoulli binary chaotic sequences. With many chaotic binary sensing architectures, we can then more easily apply CS paradigm to various fields

A Constrained Coding-Aware Routing Scheme in Wireless Ad-Hoc Networks

In wireless multi-hop networks, instead of using the traditional store-and-forward method, the relay nodes can exploit the network coding idea to encode and transmit the packets in the distributed coding-aware routing (DCAR) mechanisms, which can decrease the transmission number and achieve higher throughput. However, depending on the primary coding conditions of DCAR, the DCAR-type schemes may not only detect more coding opportunities, but also lead to an imbalanced distribution of the network load. Especially, they are not energy efficient in more complex scenarios, such as wireless ad-hoc networks. In this paper, to solve these shortcomings, we propose a constrained coding-aware routing (CCAR) mechanism with the following benefits: (1) by the constrained coding conditions, the proposed mechanism can detect good coding opportunities and assure a higher decoding probability; (2) we propose a tailored “routing + coding„ discovery process, which is more lightweight and suitable for the CCAR scheme; and (3) by evaluating the length of the output queue, we can estimate the states of coding nodes to improve the efficient coding benefit. To those ends, we implement the CCAR scheme in different topologies with the ns-2 simulation tool. The simulation results show that a higher effective coding benefit ratio can be achieved by the constrained coding conditions and new coding benefit function. Moreover, the CCAR scheme has significant advantages regarding throughput, average end-to-end delay, and energy consumption

Accepted xxx; Published xxx

Motivation. Comparison with the overall Wiener index, a novel set of overall Wiener indexes ( m RW, m RWp, m RWpc, and m RWc) were defined, which named the reduced overall Wiener indexes. The potential usefulness of the reduced overall Wiener indexes in QSAR/QSPR is evaluated by its correlation with a number of C3-C8 alkanes and by a favorable comparison with models based on the overall Wiener index and molecular connectivity indexes. This can extend the usefulness of the Wiener number, and can make the Wiener number to be a kind of widely used topological index in practice. Method. The present communication attempts to correlate boiling point, surface tension, critical Temperature and critical pressures of 38 diverse functional acyclic compounds with the reduced overall Wiener indices and to compare those with relations of the overall Wiener index and molecular connectivity indices to explore the diagnostic Results. The results show that considerably better statistics is obtained when using the reduced overall Wiener index. The reduced overall Wiener indexes provided even the same statistical results as the molecular connectivity indexes in all models with five variables, and the standard deviations provided by these two sets of indexes are rather closed. Conclusions. Summarized the results, one may conclude that the reduced overall Wiener index examined shows a good potential for QSAR and QSPR studies. It denotes some information of molecular structure, and make up for the pitfalls of Wiener index. This can extend the usefulness of the Wiener number, and can make the Wiener number to be a kind of widely used topological index in practice

Bipolar measurement matrix using chaotic sequence

In this paper, a novel paradigm of constructing measurement matrices is proposed for compressive sensing. More precisely, the chaotic bipolar sequences ({1,−1} elements) are utilized to build binarization measurement matrices of general size. By means of concentration inequalities together with covering argument, we show that our proposed bipolar matrices meet the restricted isometry property, which can ensure exact recovery from the linear samples. Moreover, numerical experiments illustrate that the proposed matrices outperform its counterparts, such as random Gaussian matrix. For practical applications, our proposed matrices are highly efficient for storage, multiplier and rapid data acquisition, and hardware realization. We hope that our framework reveals new directions for practitioners, as it attempts to put some of the chaos theory in perspective for practical compressive sensing applications