Time delay estimation in the ultrasonic flowmeter in the oil well

AbstractA new prototype of ultrasonic flowmeter used in the oil well is presented. The flowmeter depends on the time delay between the propagating times of the downstream and upstream ultrasonic pulses. The ultrasonic passageway is slanted to prevent the disadvantage introduced by the high viscosity of the oil. Two method of time delay estimation: threshold and cross-correlation are both studied and realized

Biomineralization stimulated peri-titanium implants prepared by selective laser melting

AbstractTitanium implants prepared by selective laser melting (SLM), a method of additive manufacturing, were subjected to implantation in beagle dogs for two and four weeks. Argon ion beam-polished cross sections of the implants after in vivo tests were characterized by scanning electron microscope (SEM) to evaluate the bone–implant interface and the early peri-implant biomineralization with sufficiently improved resolution. Two bone mineralization mechanisms were disclosed. As early as two weeks after implantation, a layer of new bone was found to form directly on the implant surface and bone in-growth was also observed. Osseointegration was found to establish partly at the tip of the implants. After healing for four weeks it was found that osseointegration was established around the entire tip of the implants, whereas only partly at the third thread region of the implants. The experimental evidences observed reveal that an inherent highly porous surface of the titanium implants generated by selective laser melting is favorable for new bone apposition

Dual-attention Focused Module for Weakly Supervised Object Localization

The research on recognizing the most discriminative regions provides referential information for weakly supervised object localization with only image-level annotations. However, the most discriminative regions usually conceal the other parts of the object, thereby impeding entire object recognition and localization. To tackle this problem, the Dual-attention Focused Module (DFM) is proposed to enhance object localization performance. Specifically, we present a dual attention module for information fusion, consisting of a position branch and a channel one. In each branch, the input feature map is deduced into an enhancement map and a mask map, thereby highlighting the most discriminative parts or hiding them. For the position mask map, we introduce a focused matrix to enhance it, which utilizes the principle that the pixels of an object are continuous. Between these two branches, the enhancement map is integrated with the mask map, aiming at partially compensating the lost information and diversifies the features. With the dual-attention module and focused matrix, the entire object region could be precisely recognized with implicit information. We demonstrate outperforming results of DFM in experiments. In particular, DFM achieves state-of-the-art performance in localization accuracy in ILSVRC 2016 and CUB-200-2011.Comment: 8 pages, 6 figures and 4 table

Highly toughened polylactide with novel sliding graft copolymer by in situ reactive compatibilization, crosslinking and chain extension

YesThe “sliding graft copolymer” (SGC), in which many linear poly-ε-caprolactone (PCL) side chains are bound to cyclodextrin rings of a polyrotaxane (PR), was prepared and employed to toughen brittle polylactide (PLA) with methylene diphenyl diisocyanate (MDI) by reactive blending. The SGC was in situ crosslinked and therefore transformed from a crystallized plastic into a totally amorphous elastomer during reactive blending. Meanwhile, PLA-co-SGC copolymer was formed at interface to greatly improve the compatibility between PLA and SGC, and the chain extension of PLA also occurred, were confirmed by FTIR, GPC, SEM, and TEM. The resulting PLA/SGC/MDI blends displayed super impact toughness, elongation at break and nice biocompatibility. It was inferred from these results the crosslinked SGC (c-SGC) elastomeric particles with sliding crosslinking points performed as stress concentrators and absorbed considerable energy under impact and tension process.This work was supported by the National Natural Science Foundation of China (50933001, 51221002 and 51320105012)

Genome Expression Profile Analysis of the Immature Maize Embryo during Dedifferentiation

Maize is one of the most important cereal crops worldwide and one of the primary targets of genetic manipulation, which provides an excellent way to promote its production. However, the obvious difference of the dedifferentiation frequency of immature maize embryo among various genotypes indicates that its genetic transformation is dependence on genotype and immature embryo-derived undifferentiated cells. To identify important genes and metabolic pathways involved in forming of embryo-derived embryonic calli, in this study, DGE (differential gene expression) analysis was performed on stages I, II, and III of maize inbred line 18-599R and corresponding control during the process of immature embryo dedifferentiation. A total of ∼21 million cDNA tags were sequenced, and 4,849,453, 5,076,030, 4,931,339, and 5,130,573 clean tags were obtained in the libraries of the samples and the control, respectively. In comparison with the control, 251, 324 and 313 differentially expressed genes (DEGs) were identified in the three stages with more than five folds, respectively. Interestingly, it is revealed that all the DEGs are related to metabolism, cellular process, and signaling and information storage and processing functions. Particularly, the genes involved in amino acid and carbohydrate transport and metabolism, cell wall/membrane/envelope biogenesis and signal transduction mechanism have been significantly changed during the dedifferentiation. To our best knowledge, this study is the first genome-wide effort to investigate the transcriptional changes in dedifferentiation immature maize embryos and the identified DEGs can serve as a basis for further functional characterization

Astroglial-Kir4.1 in Lateral Habenula Drives Neuronal Bursts to Mediate Depression

International audienceEnhanced bursting activity of neurons in the lateral habenula (LHb) is essential in driving depression-like behaviours, but the cause of this increase has been unknown. Here, using a high-throughput quantitative proteomic screen, we show that an astroglial potassium channel (Kir4.1) is upregulated in the LHb in rat models of depression. Kir4.1 in the LHb shows a distinct pattern of expression on astrocytic membrane processes that wrap tightly around the neuronal soma. Electrophysiology and modelling data show that the level of Kir4.1 on astrocytes tightly regulates the degree of membrane hyperpolarization and the amount of bursting activity of LHb neurons. Astrocyte-specific gain and loss of Kir4.1 in the LHb bidirectionally regulates neuronal bursting and depression-like symptoms. Together, these results show that a glia–neuron interaction at the perisomatic space of LHb is involved in setting the neuronal firing mode in models of a major psychiatric disease. Kir4.1 in the LHb might have potential as a target for treating clinical depression

A trust with abstract information verified routing scheme for cyber-physical network

Cyber-physical network (CPN) as well as cyber-physical social computing and networking (CPSCN), as the next generation of computing and networking, utilize a wide variety of sensing devices with significant sensing capabilities. However, it face huge challenge that data packet is transmitted to destination security. Data packets can be dropped by malicious nodes in CPN/CPSCN, causing serious damage to the network. Thus, ensuring the security of data transmission is a crucial issue for wireless sensor networks which is one of the important component of CPN/CPSCN. In this paper, a trust with abstract information verified (TAIV) routing scheme is proposed to improve the data packet arrival ratio. In the TAIV scheme, backbone routing paths are created by constructing an optimal connected dominating set (CDS). CDS routing ensures communication among all nodes in the network. In addition, as the source node sends the data packet to the destination through the backbone routing path, the abstract information is also transmitted to the destination through the auxiliary routing path to allow the destination node to know whether data has been sent to it. Depending on whether the data packet is transmitted to the destination or dropped by the malicious node and whether the abstract message is transmitted to the destination successfully, the destination will reduce or increase the trust in nodes in this routing path accordingly. After a period of time, the trust information of nodes will be diffused by information exchange. If the trust information is sufficient, the malicious node, whose trust is lower than that of the normal node, will be identified and eliminated from the backbone routing path, reducing the number of malicious nodes in the backbone. Thus, the data packet arrival ratio will be improved. The theoretical analysis shows that compared with the previous scheme, the data packet arrival ratio increases by 4.251%-80.208%, and nearly all malicious nodes are identified while retaining long network lifetime.Cyber-physical network (CPN) as well as cyber-physical social computing and networking (CPSCN), as the next generation of computing and networking, utilize a wide variety of sensing devices with significant sensing capabilities. However, it face huge challenge that data packet is transmitted to destination security. Data packets can be dropped by malicious nodes in CPN/CPSCN, causing serious damage to the network. Thus, ensuring the security of data transmission is a crucial issue for wireless sensor networks which is one of the important component of CPN/CPSCN. In this paper, a trust with abstract information verified (TAIV) routing scheme is proposed to improve the data packet arrival ratio. In the TAIV scheme, backbone routing paths are created by constructing an optimal connected dominating set (CDS). CDS routing ensures communication among all nodes in the network. In addition, as the source node sends the data packet to the destination through the backbone routing path, the abstract information is also transmitted to the destination through the auxiliary routing path to allow the destination node to know whether data has been sent to it. Depending on whether the data packet is transmitted to the destination or dropped by the malicious node and whether the abstract message is transmitted to the destination successfully, the destination will reduce or increase the trust in nodes in this routing path accordingly. After a period of time, the trust information of nodes will be diffused by information exchange. If the trust information is sufficient, the malicious node, whose trust is lower than that of the normal node, will be identified and eliminated from the backbone routing path, reducing the number of malicious nodes in the backbone. Thus, the data packet arrival ratio will be improved. The theoretical analysis shows that compared with the previous scheme, the data packet arrival ratio increases by 4.251%-80.208%, and nearly all malicious nodes are identified while retaining long network lifetime