Barrier coverage of wireless sensor networks is an important issue in the detection of intruders who are attempting to cross a region of interest.However,in certain applications,barrier coverage ...cannot be satisfied after random deployment.In this paper,we study how mobile sensors can be efficiently relocated to achieve k-barrier coverage.In particular,two problems are studied：relocation of sensors with minimum number of mobile sensors and formation of k-barrier coverage with minimum energy cost.These two problems were formulated as 0–1 integer linear programming（ILP）.The formulation is computationally intractable because of integrality and complicated constraints.Therefore,we relax the integrality and complicated constraints of the formulation and construct a special model known as RELAX-RSMN with a totally unimodular constraint coefficient matrix to solve the relaxed 0–1 ILP rapidly through linear programming.Theoretical analysis and simulation were performed to verify the effectiveness of our approach.
•Nondestructive measurement of TVB-N in pork meat by integrating three techniques.•Correlation analysis of the three sensors data with TVB-N content of pork meat.•Extraction of the optimum feature ...variables from three sensors data.•Data fusion based on feature variables and BP-ANN model for measuring TVB-N content.
Total volatile basic nitrogen (TVB-N) content is an important reference index for evaluating pork freshness. This paper attempted to measure TVB-N content in pork meat using integrating near infrared spectroscopy (NIRS), computer vision (CV), and electronic nose (E-nose) techniques. In the experiment, 90 pork samples with different freshness were collected for data acquisition by three different techniques, respectively. Then, the individual characteristic variables were extracted from each sensor. Next, principal component analysis (PCA) was used to achieve data fusion based on these characteristic variables from 3 different sensors data. Back-propagation artificial neural network (BP-ANN) was used to construct the model for TVB-N content prediction, and the top principal components (PCs) were extracted as the input of model. The result of the model was achieved as follows: the root mean square error of prediction (RMSEP)=2.73mg/100g and the determination coefficient (Rp2)=0.9527 in the prediction set. Compared with single technique, integrating three techniques, in this paper, has its own superiority. This work demonstrates that it has the potential in nondestructive detection of TVB-N content in pork meat using integrating NIRS, CV and E-nose, and data fusion from multi-technique could significantly improve TVB-N prediction performance.
The development of structurally novel nucleoside analogues is an active area in medicinal chemistry, since these drugs have proven clinical efficacy for decades. Azanucleosides are nucleoside ...analogues in which the sugar moieties are composed of nitrogen-containing rings or chains. In recent years, many azanucleosides have demonstrated therapeutic potential. In this short review, we describe recent advancements in azanucleosides, which may translate in a better understanding of the molecular design, biological activity, structure–activity relationship, and their related mechanism of action. The information summarized in this paper should encourage medicinal chemists in their future efforts to create more potent and effective chemotherapeutic agents.
The Phanerozoic tectonic regimes of the South China Block (SCB) hold a key to understanding of its geodynamic evolution with respect to formation of numerous mineral resources. Despite long-time ...debates in the past three decades, there is still no consensus on the two key points whether the Phanerozoic tectonothermal events were due to subduction of the Pacific plate or intracontinental reworking and whether the three periods of tectonothermal events in the middle Paleozoic (Kwangsian), Triassic (Indosinian) and Jurassic–Cretaceous (Yanshanian) are mainly driven by tectonic transition in subduction of the oceanic crust from Paleotethyan in the west to Pacific in the east. This paper presents an overview of key geological observations in the SCB with respect to its Phanerozoic tectonics. Available data show that there are distinctive sedimentary, magmatic, structural and metamorphic records across the Xuefeng-Jiangnan Domain in the SCB. The geological signatures associated with the Kwangsian and Indosinian tectonothermal events are predominantly preserved in the eastern SCB, including the eastern Yangtze and Cathaysia Blocks to the east of the Xuefeng-Jiangnan Domain. They are characterized by strong thrusting/transpression, anatexic granitic magmatism, high-grade metamorphism and the poor involvement of the juvenile mantle-derived rocks. The two events were dated at ca. 400–460Ma and ca. 200–250Ma, respectively. The Yanshanian tectonothermal event is dominantly represented by the development of a wide magmatic belt of exceeding 1300km (from the coastal province to the Xuefeng-Jiangnan Domain) and a broad deformational belt of more than 2000km (from the coastal province to the Sichuan basin). The Yanshanian I-, S- and A-type granites, syenite and volcanic rocks display two arrays, which are oblique and parallel to the coastal provinces of the southeast China, respectively. They were mainly formed at the three age-spans of 152–180Ma, 120–130 and 87–107Ma with the peak of 158Ma, 125Ma and 93Ma, respectively. The stillstand time of the Yanshanian magmatism was temporally overlapped by the deformation time of the top-to-the-NW progressive transpression or sinistral strike-slip at 132–142Ma and 95–112Ma, respectively. In conjunction with the observations and controversies, a geodynamic model is proposed for the Mesozoic tectonic evolution of the SCB.
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► Introduction of the key geological observations on the Phanerozoic tectonics of the SCB hinterland. ► Description and discussion of the existing hypotheses and controversies on the Phanerozoic tectonics of the SCB. ► A geodynamic model for the Mesozoic tectonic evolution of the SCB is herein proposed.
The Phanerozoic record of Southeast Asia preserves the history of opening and subsequent consumption of the Paleotethyan Ocean and the assembly of continental fragments into Asia as part of the ...broader-scale reconstruction of Pangea. However, uncertainty remains as to which of the many suture zones in Southeast Asia represents the relict of the main ocean, when final ocean closure occurred, and the assembly history of the Eastern Cimmerian and Southeast Asia continental fragments. Our overview of the geological features of the suture zones, the bounding continental fragments and their magmatic, metamorphic and sedimentary records resolves many of these key issues. The sedimentary, biogeographical, structural, lithological, geochemical and geochronological data from the Changning-Menglian, Inthanon and Bentong-Raub suture zones argue for their linkage with the Longmu Co-Shuanghu suture zone in Central Tibet, and together constitute the main East Paleotethyan Ocean relict. The eastward subduction of the ocean resulted in the development of a series of magmatic arc-back-arc basin and continental fragments in Southeast Asia, including, from west to east, the Lincang-Sukhothai-East Malaya arc, the Jinghong-Nan-Sa Kaeo back-arc basin, the Simao/west Indochina fragment, the Luang Prabang-Loei back-arc basin, the south Indochina fragment, the Wusu and Truong Son back-arc basins, the north Indochina fragment, the Jinshajiang-Ailaoshan-Song Ma branch/back-arc basin and the South China Block. Assembly of these fragments resulted in Indosinian high temperature and high pressure metamorphism and related tectonothermal event. Available data indicate a switch from subduction of the main East Paleotethyan Ocean to the collision of the Sibumasu with Simao/Indochina blocks at ~237Ma, with subsequent syn- and post-collisional events at ~237–230Ma and ~230–200Ma, respectively, along the Changning-Menglian, Inthanon and Bentong-Raub suture zones. The timing of initial-, syn- and post-collision events along the Jinshajiang-Ailaoshan-Song Ma suture zone with its record of back-arc basin closure is at ~247Ma, ~247–237Ma and ~237–200Ma, generally ~10Ma older than that along the Changning-Menglian, Inthanon and Bentong-Raub suture zones. Our synthesis of all available data enables establishment of a comprehensive geodynamic model for the East Paleotethyan evolution. This model links the spatial-temporal pattern across Southeast Asia into a series of tectonic events including ocean/back-arc basin opening, subduction/closure, subsequent assemblage and orogenic collapse, along with associated igneous, metamorphic and sedimentary activities.
Both caching and interference alignment (IA) are promising techniques for next-generation wireless networks. Nevertheless, most of the existing works on cache-enabled IA wireless networks assume that ...the channel is invariant, which is unrealistic considering the time-varying nature of practical wireless environments. In this paper, we consider realistic time-varying channels. Specifically, the channel is formulated as a finite-state Markov channel (FSMC). The complexity of the system is very high when we consider realistic FSMC models. Therefore, in this paper, we propose a novel deep reinforcement learning approach, which is an advanced reinforcement learning algorithm that uses a deep Q network to approximate the Q value-action function. We use Google TensorFlow to implement deep reinforcement learning in this paper to obtain the optimal IA user selection policy in cache-enabled opportunistic IA wireless networks. Simulation results are presented to show that the performance of cache-enabled opportunistic IA networks in terms of the network's sum rate and energy efficiency can be significantly improved by using the proposed approach.
Total viable count (TVC) of bacteria is one of the most important indexes in evaluation of quality and safety of meat. In this work, the TVC in pork meat was detected by hyperspectral imaging ...technology. First, the spectra were extracted from 3-D datacube of hyperspectral image and 100 characteristic variables were selected by synergy interval PLS (SI-PLS) algorithm. Meanwhile, principal component analysis (PCA) was implemented on the 3-D datacube to determine 3 characteristic pictures. And, 5 characteristic variables were extracted using texture analysis from each characteristic picture. PCA was implemented on 111 spectra variables, 15 image variables and data fusion (126 variables), and the top principal components (PCs) were extracted for developing the TVC prediction model, respectively. Experimental results show that the model based on data fusion is superior to others, which was achieved with RMSEP=0.243lgCFU/g and Rp2=0.8308 in the prediction set. This work demonstrates that HSI technique, as a nondestructive analytical tool, has the potential in nondestructive detection of TVC in pork meat.
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•Rapid detection of total viable count (TVC) in pork meat by hyperspectral imaging•Data fusion based on spectral and image information from hyperspectral data•Construction of nonlinear regression model based on data fusion
Plasticized poly (lactic acid) (PPLA) was prepared by melt blending poly (lactic acid) (PLA) with 10 wt% of poly (ethylene glycol) (PEG), with varied molecular weights range from 400 to 4000. The ...structure, thermal property, morphology, and surface free energy of the PPLA were investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and contact angles (CA). The resulting PPLA results indicated that the introduction of PEG to the blend systems resulted in a ductile fracture, a decrease in the melt temperature (Tm) and glass transfer temperature (Tg), and an increase in the degree of crystallization (χc), which indicated an improved flexibility. In addition, the polarity of the PPLA increased and the surface free energy decreased. The resulting PPLA was subsequently used as matrix to blend with wood flour to prepare composites. The mechanical strength, melting behavior, thermal stability, and microscopy of the PPLA/wood flour composites were also evaluated. These results illustrated that the plasticized PPLA matrix was beneficial to the interfacial compatibility between the polar filler and the substrate.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the eastern South China Block (SCB), the presence of middle Paleozoic volcanics and mafic rocks is poor in spite of the extensive occurrence of granites in response to the synchronous (Kwangsian) ...intracontinental orogen event. The nature of the lithosphere and its associated orogenic process are poorly known for such a major orogen. In this paper, a set of new U–Pb zircon geochronological, elemental and Sr–Nd isotopic data are presented for several gabbroic plutons, which were recently identified in the Cathaysia Block. The representative samples of the Longhugang, Xinchuan and Xinsi plutons yielded the weighted mean 206Pb/238U ages of 423±8Ma, 434±6Ma and 420±3Ma, respectively, and their gneissoid country-rocks are dated at 442–466Ma. This evidences the presence of Silurian mafic rocks in the Cathaysia Block. These gabbroic rocks can be geochemically classified into three groups. Group 1 from the western Longhugang pluton exhibits flat REE patterns represented by (La/Yb)cn=1.1–1.7, (Gd/Yb)cn=0.99–1.15, and δEu=1.29–1.51 with negative Nb–Ta and P and markedly positive Sr anomalies. It shows enrichment in LILEs and 87Sr/86Sr(t) ratios of 0.70412–0.70727 and εNd(t) values of −2.6 to −0.6. Group 2 from the Xinchuan, Zhouya and Yunlu plutons is characterized by high MgO (11.4–15.8wt.%), mg-number (66–74) and Cr and Ni contents. It is marked by significantly negative Nb–Ta, Zr–Hf and P–Ti anomalies with high 87Sr/86Sr(t) (0.70920–0.71072) and low εNd(t) values (−3.9 to −7.9). Group 3 from the Xinsi and eastern Longhugang plutons has εNd(t) values from −2.8 to −5.7 and shows high Nb content of 7.05–9.89ppm with pronounced enrichment in LILE and weak depletion in HFSE, resembling Nb-enriched arc basalt in HFSE composition. A synthesis of these geochemical data points to the following petrogenesis: Groups 1 and 2 derived from a spinel-bearing, plagioclase-rich source and a garnet-bearing, orthopyroxene-rich source, respectively, proportionally modified by slab- and sediment-derived melts plus fluid fluxing from the earliest Neoproterozoic subduction. The HFSE composition for Group 3 inherited from a metasomatized mantle wedge column with the input of large-proportional slab melts and the absence of residual rutile during partial melting. In conjunction with other available observations, it is proposed that there preserved a paleosubduction-modified wedge column beneath the Cathaysia Block, which might be undisturbed until the Kwangsian intracontinental orogen. During the Silurian post-orogenic collapse of the event, the elevated lithosphere thermal boundary facilitated the partial melting of the column to generate these Silurian gabbroic rocks.
► Three gabbro plutons from Yunkai–Nanling are dated at 420–434Ma, confirming the presence of Silurian mafic rocks in SCB. ► These mafic rocks originated from the wedge column previously modified by subduction-derived components. ► The post-collisional collapse of the Kwangsian intracontinental orogen is proposed as the petrogenetic model of the gabbro. ► The earliest Neoproterozoic subduction-related metasomatism might occur along the southern Cathaysia Block.
High performance lithium ion conducting Li7La3Zr2O12 solid electrolytes are prepared for the first time by field assisted sintering technology (FAST). The effect of sintering temperature on the phase ...compositions, microstructure and Li ionic conductivity is systematically investigated. The results show that pure cubic phase LLZO can be obtained at a range of temperatures from 1100 to 1180 °C for no more than 10 min. For the sample sintered at 1150 °C, a maximum relative density of 99.8% with a total ionic conductivity as high as 5.7 × 10−4 S cm−1 are obtained at room temperature. This value is the highest among the present research. Compared with the traditional preparation methods, the current FAST is very promising to obtain high performance LLZO for its advantages of very short sintering time, a single preparation step of reaction-densification processing, and relatively lower sintering temperature.
•Pure cubic LLZO is firstly prepared by field assisted sintering technology.•Cubic LLZO is obtained at lower temperature within a very short sintering time.•The prepared LLZO has the highest Li ionic conductivity in the present research.•This work provides a new and very promising method for this material.
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