Decision Diagram Based Symbolic Algorithm for Evaluating the Reliability of a Multistate Flow Network

Evaluating the reliability of Multistate Flow Network (MFN) is an NP-hard problem. Ordered binary decision diagram (OBDD) or variants thereof, such as multivalued decision diagram (MDD), are compact and efficient data structures suitable for dealing with large-scale problems. Two symbolic algorithms for evaluating the reliability of MFN, MFN_OBDD and MFN_MDD, are proposed in this paper. In the algorithms, several operating functions are defined to prune the generated decision diagrams. Thereby the state space of capacity combinations is further compressed and the operational complexity of the decision diagrams is further reduced. Meanwhile, the related theoretical proofs and complexity analysis are carried out. Experimental results show the following: (1) compared to the existing decomposition algorithm, the proposed algorithms take less memory space and fewer loops. (2) The number of nodes and the number of variables of MDD generated in MFN_MDD algorithm are much smaller than those of OBDD built in the MFN_OBDD algorithm. (3) In two cases with the same number of arcs, the proposed algorithms are more suitable for calculating the reliability of sparse networks

FindVehicle and VehicleFinder: A NER dataset for natural language-based vehicle retrieval and a keyword-based cross-modal vehicle retrieval system

Natural language (NL) based vehicle retrieval is a task aiming to retrieve a vehicle that is most consistent with a given NL query from among all candidate vehicles. Because NL query can be easily obtained, such a task has a promising prospect in building an interactive intelligent traffic system (ITS). Current solutions mainly focus on extracting both text and image features and mapping them to the same latent space to compare the similarity. However, existing methods usually use dependency analysis or semantic role-labelling techniques to find keywords related to vehicle attributes. These techniques may require a lot of pre-processing and post-processing work, and also suffer from extracting the wrong keyword when the NL query is complex. To tackle these problems and simplify, we borrow the idea from named entity recognition (NER) and construct FindVehicle, a NER dataset in the traffic domain. It has 42.3k labelled NL descriptions of vehicle tracks, containing information such as the location, orientation, type and colour of the vehicle. FindVehicle also adopts both overlapping entities and fine-grained entities to meet further requirements. To verify its effectiveness, we propose a baseline NL-based vehicle retrieval model called VehicleFinder. Our experiment shows that by using text encoders pre-trained by FindVehicle, VehicleFinder achieves 87.7\% precision and 89.4\% recall when retrieving a target vehicle by text command on our homemade dataset based on UA-DETRAC. The time cost of VehicleFinder is 279.35 ms on one ARM v8.2 CPU and 93.72 ms on one RTX A4000 GPU, which is much faster than the Transformer-based system. The dataset is open-source via the link https://github.com/GuanRunwei/FindVehicle, and the implementation can be found via the link https://github.com/GuanRunwei/VehicleFinder-CTIM

Molecular helices as electron acceptors in high-performance bulk heterojunction solar cells

Despite numerous organic semiconducting materials synthesized for organic photovoltaics in the past decade, fullerenes are widely used as electron acceptors in highly efficient bulk-heterojunction solar cells. None of the non-fullerene bulk heterojunction solar cells have achieved efficiencies as high as fullerene-based solar cells. Design principles for fullerene-free acceptors remain unclear in the field. Here we report examples of helical molecular semiconductors as electron acceptors that are on par with fullerene derivatives in efficient solar cells. We achieved an 8.3% power conversion efficiency in a solar cell, which is a record high for non-fullerene bulk heterojunctions. Femtosecond transient absorption spectroscopy revealed both electron and hole transfer processes at the donor−acceptor interfaces. Atomic force microscopy reveals a mesh-like network of acceptors with pores that are tens of nanometres in diameter for efficient exciton separation and charge transport. This study describes a new motif for designing highly efficient acceptors for organic solar cells

Identification of Major QTLs Associated With First Pod Height and Candidate Gene Mining in Soybean

First pod height (FPH) is a quantitative trait in soybean [Glycine max (L.) Merr.] that affects mechanized harvesting. A compatible combination of the FPH and the mechanized harvester is required to ensure that the soybean is efficiently harvested. In this study, 147 recombinant inbred lines, which were derived from a cross between ‘Dongnong594’ and ‘Charleston’ over 8 years, were used to identify the major quantitative trait loci (QTLs) associated with FPH. Using a composite interval mapping method with WinQTLCart (version 2.5), 11 major QTLs were identified. They were distributed on five soybean chromosomes, and 90 pairs of QTLs showed significant epistatic associates with FPH. Of these, 3 were main QTL × main QTL interactions, and 12 were main QTL × non-main QTL interactions. A KEGG gene annotation of the 11 major QTL intervals revealed 8 candidate genes related to plant growth, appearing in the pathways K14486 (auxin response factor 9), K14498 (serine/threonine-protein kinase), and K13946 (transmembrane amino acid transporter family protein), and 7 candidate genes had high expression levels in the soybean stems. These results will aid in building a foundation for the fine mapping of the QTLs related to FPH and marker-assisted selection for breeding in soybean

Influence of Cutter Head on Cavitation of Non-Jammed Submerged Grinder Pump

For the investigation of the cavitation of non-jammed submersible grinder pumps, a GSP-22 model pump was numerically simulated based on CFX. ICEM-CFD was applied to a structured mesh for the flow components. Pump performance and the influence of the cutter head on cavitation with different cutter head numbers and shapes were investigated. The results were as follows: with increases in the number of cutter heads, the effects of the cutter heads on the water increased, and the flow rate near the cutter head increased correspondingly—which eventually led to aggravated cavitation near the cutter head of the non-jammed submersible grinder pump. The head of the submersible grinder pump with a streamlined cutter changed little compared to the pump with a non-streamlined cutter; the overall power declined by 13.2% and the highest efficiency increased by 6%. For all pumps with different numbers of cutter heads, the vapor volume fraction of the streamlined cutter head was lower than that of the non-streamlined cutter head, and the vapor distribution area size of the streamlined cutter head was smaller than that of the non-streamlined cutter head. This means that changing the cutter head shape to streamlined can effectively control the cavitation intensity near the cutter head

Thermal Performance and Geometric Optimization of Fractal T-Shaped Highly-Conductive Material for Cooling of a Rectangular Chip

To improve the thermal performance of inserted highly-conductive material (HCM) for the cooling of a chip, the present work numerically investigates the effects of various geometric and structural parameters of a fractal T-shaped branched HCM on the maximum temperature of the chip. These parameters include the length ratios of branches at two consecutive branching levels α, the width ratio of branches at two consecutive branching levels β, the maximum branching level m, the length of the branch at the initial level L0, the thickness of the HCM H, and the total volume of the HCM V. The results indicate that the maximum temperature of the chip first drops and then rises with the increase of β, which means the existence of the optimal geometric structure of the branched HCM for the cooling of the chip. In addition, the maximum temperature of the chip decreases with the increase of m and V, decreases with the decrease of H, while first drops and then rises with the increase of α and L0. Further, the present work investigates the effects of the thermal conductivity ratio of HCM and chip γ on the optimal width ratio βm of the branched HCM with a different length ratio α, maximum branching level m, length of the branch at the initial level L0, thickness H, total volume V, and thermal conductivity of the rectangular chip Kc. It was found that βm increases with the increase of γ and V, and decreases with the increase of α, L0, and H. The present finding is beneficial to the improvement of the thermal performance of the inserted HCM via geometric optimization

Sorption of oxytetracycline in particulate organic matter in soils and sediments: Roles of pH, ionic strength and temperature

Particulate organic matter (POM) is a fraction of organic matter with dissimilar properties in different soils. POM isolated from soils and sediments (wetland, oil waste field, farmlands and aquaculture pond sediment) was used to study its sorption behavior on the antibiotic oxytetracydine (OTC). Impacts of solution pH, ionic strength and temperature on the OTC sorption were studied. The sorption rates of OTC in POM from wetland (POM-w) and farmland (POM-f1, POM-f2) were rapid during the first 3 h and gradually decreased with reaction time until reaching the equilibrium. Linear sorption occurred from 3 to 12 h in POM from oil waste field land (POM-o) and aquaculture pond sediment ( POM-a). The organic carbon normalized partition coefficient (k(oc)) varied from 215.0 to 4493.6 L kg(-1), and it was nearly 10x higher for the POM-w, POM-f1 and POM-f2 than in the POM-o and POM-a. Sorption of OTC by POM exhibited strong pH dependence. Ionic factors affected OTC sorption in POM-f1, POM-12 and POM-a. The sorption capacity declined >50% in a solution with Ca2+ compared to other ions with similar ionic strength. Sorption thermodynamics showed an entropy increasing and endothermic progress during the OTC sorption in POM, implying a spontaneous sorption process. Several mechanisms were involved in OTC sorption in POM, including hydrogen bonding, cation exchange, hydrophobic partitioning and surface complexation. (C) 2020 Elsevier B.V. All rights reserved

Features of Transient Flow during Collapse of Nuclear Power Pump Cavitation

Abstract: Collapse of cavitation in flow passage of impeller for centrifugal pump was stimulated by CFX to numerically stimulate internal features of cavitation when pressure at entrance continuing to decline. Results of numerical simulation and tests presented consistent tendency. Cvol in the flow passage of impeller was zero for a while in the occurrence of cavitation collapse and then increased sharply. After reaching a certain value, Cvol began to increase slowly. The amplitudes of head fluctuations increased with decreasing flow within the interval prior to a specific value and then increased with increasing flow

Sialylation: An alternative to designing long-acting and targeted drug delivery system

Long-acting and specific targeting are two important properties of excellent drug delivery systems. Currently, the long-acting strategies based on polyethylene glycol (PEG) are controversial, and PEGylation is incapable of simultaneously possessing targeting ability. Thus, it is crucial to identify and develop approaches to produce long-acting and targeted drug delivery systems. Sialic acid (SA) is an endogenous, negatively charged, nine-carbon monosaccharide. SA not only mediates immune escape in the body but also binds to numerous disease related targets. This suggests a potential strategy, namely “sialylation,” for preparing long-acting and targeted drug delivery systems. This review focuses on the application status of SA-based long-acting and targeted agents as a reference for subsequent research

Effect of gas quantity on two-phase flow characteristics of a mixed-flow pump

The inlet gas quantity has a great influence on the performance and inner flow characteristics of a mixed-flow pump. In this article, both numerical and experimental methods are used to carry out this research work. The effects under the steady gas volume fraction state and the transient gas quantity variation process on the mixed-flow pump are investigated and compared in detail. It could be concluded that the head of the mixed-flow pump shows slight decline at the low gas volume fraction state, while it decreases sharply at the high gas volume fraction state and then decreases with the increasing gas quantity. There is an obvious asymmetric blade vapor density on the blade suction side under each cavitation state. The cavities can be weakened obviously by increasing the inlet gas volume fraction within a certain range. It has little influence on the internal unsteady flow of the mixed-flow pump when the gas volume fraction is less than 10%, but the pump starts to operate with a great unsteady characteristic when the inlet gas volume fraction increases to 15%