1,077 research outputs found

    Unipolar Resistance Switching in Amorphous High-k dielectrics Based on Correlated Barrier Hopping Theory

    Full text link
    We have proposed a kind of nonvolatile resistive switching memory based on amorphous LaLuO3, which has already been established as a promising candidate of high-k gate dielectric employed in transistors. Well-developed unipolar switching behaviors in amorphous LaLuO3 make it suited for not only logic but memory applications using the conventional semiconductor or the emerging nano/CMOS architectures. The conduction transition between high- and low- resistance states is attributed to the change in the separation between oxygen vacancy sites in the light of the correlated barrier hopping theory. The mean migration distances of vacancies responsible for the resistive switching are demonstrated in nanoscale, which could account for the ultrafast programming speed of 6 ns. The origin of the distributions in switching parameters in oxides can be well understood according to the switching principle. Furthermore, an approach has also been developed to make the operation voltages predictable for the practical applications of resistive memories.Comment: 18 pages, 6 figure

    Horizontal heat flux between urban buildings and soil and its influencing factors

    Get PDF
    The soil temperature near four external walls with different orientations was investigated in spring and summer. In both seasons, the soil temperature was higher in the positions closest to the buildings, suggesting that the buildings were a heat source for the soil surrounding them. Therefore, it could be confirmed that there was lateral heat transfer between the soil and the buildings. Based on this, a soil heat flux plate was set between the soil and the buildings to investigate the horizontal heat flux. The data showed diurnal variations of the horizontal heat flux in both spring and summer. In order to determine the factors that influenced the horizontal heat flux and to provide a basis to understand its mechanism, the correlations between the data of several meteorological factors and the horizontal heat flux were analysed. The results showed that solar radiation was significantly correlated with the horizontal heat flux (p0.05), such as that for soil moisture. The stepwise regression results indicated that the relative importance of these meteorological factors was 48.63, 21.94, 14.44, 8.12 and 6.87% for solar radiation, soil temperature, air temperature, relative humidity and soil moisture, respectively, on a diurnal scale

    Multiobjective Location Model Design Based on Government Subsidy in the Recycling of CDW

    Get PDF
    With the generation of a large amount of construction and demolition waste (CDW), many scholars have recently paid more attention to the recycling of CDW. In this paper, we design a classification recycling method based on the degree of CDW availability in the recycling of CDW. Considering the important role of the government in reverse logistics, a model of reverse logistics network based on the trade-off between cost and recycling rate is put forward, which is subject to government subsidy. The model includes the location of classification processing center and ensures the best route of transportation. Then, the improved particle swarm optimization algorithm is applied to solve the model to get Pareto frontier by transforming it into a multiobjective integer-programming problem. As a case study, the results of the statistical modeling used in this study indicate the feasibility of the model. Finally, according to the sensitivity analysis of government’s subsidy, we evaluate the effectiveness of this program and its applicability

    Members of miR-169 family are induced by high salinity and transiently inhibit the NF-YA transcription factor

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) are endogenously expressed small RNAs with a length of about 21 nt. MiRNAs silence their target genes at the post-transcriptional level. In plants, miRNAs play various developmental and physiological roles by cleavaging mRNAs predominantly. Drought and high salinity are the most severe environmental abiotic stresses and cause crop losses all over the world.</p> <p>Results</p> <p>In this study, we identified miR-169g and miR-169n (o) as high salinity-responsive miRNAs in rice. MiR-169n and miR169o were in a miRNA cluster with a distance of 3707 base pairs (bp). The high degree of conservation and close phylogenic distance of pre-miR-169n and pre-miR-169o indicated that they were derived from a very recent tandem duplication evolutionary event. The existence of a cis-acting abscisic acid responsive element (ABRE) in the upstream region of miR-169n (o) suggested that miR-169n (o) may be regulated by ABA. In our previous study, we found that miR-169g was induced by the osmotic stress caused by drought via a dehydration-responsive element (DRE). Thus, our data showed that there were both overlapping and distinct responses of the miR-169 family to drought and salt stresses. We also showed that these miR-169 members selectively cleaved one of the NF-YA genes, Os03g29760, which is a CCAAT-box binding transcription factor and participates in transcriptional regulation of large number genes. Finally, we found one or more ath-miR-169 member that was also induced by high salinity.</p> <p>Conclusion</p> <p>We identified members of the miR-169 family as salt-induced miRNAs and analyzed their evolution, gene organization, expression, transcriptional regulation motif and target gene. Our data also indicated that the salt-induction of some miR-169 members was a general property in plants.</p

    Parasite Species Associated With Wild Plateau Pika (Ochotona Curzoniae) In Southeastern Qinghai Province, China

    Get PDF
    A survey was conducted to determine the prevalence and seasonal abundance of egg, larval, and adult stages of helminths; oocyts of protozoans; and ectoparasites of plateau pikas (Ochotona curzoniae) in seven areas of southeastern Qinghai Province, China, during August 2006 and May 2007. Fecal samples collected from 430 plateau pikas were examined by the modified McMaster technique, which revealed that 83% of the samples contained eggs from two or more helminth species. Mean fecal egg counts were generally moderate and showed the same trend irrespective of the age or sex of the pikas. The prevalence and counts of cestode eggs showed strong seasonal relationships that corresponded with the rainfall pattern in the study area during the study period. Of the 430 plateau pika examined at necropsy, 89% contained adult nematode or cestode species, but none of these contained adult trematode species or protozoans. Overall, six genera of adult nematodes including Oesophagostomum sp., Cephaluris coloradensis, Eugenuris schumakowiescsi, Haemonchus sp., Trichuris sp., and Chbertiinae sp.; three genera of adult cestodes including Schizorchis sp., Ochotonae sp., and Hymenolepis nana; three ectoparasite species including Hypoderma curzonial, Pulex sp., and Ixodes ovatus; and one proscolex stage of a cestode, Echinococcus multilocularis or Echinococcus shiquicus, were encountered during the study. Other genera examined occurred in low numbers, which did not allow any meaningful comparisons. Overall, results suggest that four parasite species, Hypoderma curzonial, Pulex sp., Ixodes ovatus Neumann, and Cephaluris coloradensis, may be regulating factors in controlling future numbers of plateau pika in this study area. These data provide evidence of a natural biologic control mechanism of plateau pika on grassland habitats, and may be of use for identifying the mechanism of transmission of parasites between plateau pika, livestock, and humans

    Environmental Molecular Effect on the Macroscale Friction Behaviors of Graphene

    Get PDF
    This study investigated the friction behavior of graphene in air and nitrogen atmosphere environments. The microstructural evolution caused by the variation of atmosphere environments and its effect on the friction coefficient of the graphene is explored. It is demonstrated that graphene can exhibit excellent lubricating properties both in air and nitrogen atmosphere environments. In air, a highly ordered layer-by-layer slip structure can be formed at the sliding interface. Oxygen and H2O molecules can make edge dangling bonds and defects passive. Thus the interaction between the nanosheets and the layers of nanosheets is weak and the friction coefficient is low (0.06–0.07). While the friction coefficient increases to 0.14–0.15 in a nitrogen atmosphere due to the interaction of defects generated in the sliding process, the nitrogen molecules with lone pair electrons can only make the nanosheets passive to a certain degree, thus the ordered slip structure is destroyed and friction is higher. This work reveals the influence of environmental molecules on the macroscale tribological performances of graphene and its effect on the microstructure at the sliding interface, which could shed light on the lubricating performance of graphene in environmental atmospheres and help us to understand the tribological behaviors of graphite at the macroscale

    Novel Variants Identified in Multiple Sclerosis Patients From Southern China

    Get PDF
    Background: Multiple sclerosis (MS) is an autoimmune and demyelinating disease. Genome-wide association studies have shown that MS is associated with many genetic variants in some human leucocyte antigen genes and other immune-related genes, however, those studies were mostly specific to Caucasian populations. We attempt to address whether the same associations are also true for Asian populations by conducting whole-exome sequencing on MS patients from southern China.Methods: Genomic DNA was extracted from the peripheral blood mononucleocytes of 8 MS patients and 26 healthy controls and followed by exome sequencing.Results: In total, 41,227 variants were found to have moderate to high impact on their protein products. After filtering per allele frequencies according to known database, 17 variants with the allele frequency &lt;1% or variants with undetermined frequency were identified to be unreported and have significantly different frequencies between the MS patients and healthy controls. After validation via Sanger sequencing, one rare variant located in exon 7 of TRIOBP (Chr22: 37723520G&gt;T, Ala322Ser, rs201693690) was found to be a novel missense variant.Conclusion: MS in southern China may have association with unique genetic variants, our data suggest TRIOBP as a potential novel risk gene

    Precise emergency load shedding approach for distributed network considering response time requirements

    Get PDF
    Emergency load shedding (ELS) is a vital measure for power systems to manage extreme events, ensuring the safety, stability, and economic operation of the grid. The integration of distributed energy resources and controllable devices in modern power systems has bolstered grid flexibility. Consequently, developing precise load shedding strategies to balance economic and security goals has emerged as a prominent subject in power system optimization. However, existing methods exhibit inadequacies, including overlooking practical operability, privacy concerns, and a lack of adaptability to response time requirements. To address these gaps, this paper introduces a precise ELS approach for distributed networks with a focus on response time needs. Contributions encompass designing load shedding processes for various response times, integrating demand response, and partitioning networks for optimized load shedding. Through validation using standard test cases, the proposed approach effectively utilizes response time and demand-side resources for precise ELS control in distribution networks. It accommodates different scenarios, offering a robust solution for rapid and accurate load shedding during emergencies

    Preliminary study on involving field irradiation radiotherapy in neoadjuvant chemoradiotherapy for esophageal cancer

    Get PDF
    Background and purpose: The standard treatment for patients with locally advanced esophageal cancer is neoadjuvant chemoradiotherapy (NCRT) plus radical resection. However, the technical aspects for implementing this comprehensive treatment strategy differ, especially in the controversial definition of the radiotherapy target area in NCRT. This study aimed to analyze the feasibility of involving field irradiation (IFI) in NCRT for locally advanced esophageal cancer. Methods: Retrospective analysis of locally advanced esophageal squamous cell carcinoma patients receiving NCRT in Shanghai Chest Hospital, Shanghai Jiao Tong University School of Medicine from July 2016 to May 2017 showed that the radiotherapy target of all patients was our recommended IFI. The radiotherapy plan was redesigned for the enrolled patients according to the two traditional target delineation of elective node irradiation (ENI) and primary subclinical lesion irradiation (SLI). The dosimetric parameters of the three groups and the dose differences of organ at risk (OAR), such as lungs, heart and spinal cord, were compared, and the relationship between IFI Recurrence pattern and radiation target volumes was analyzed. Results: A total of 26 patients were enrolled. The average target volume of IFI was (277±77) cm3, which was significantly lower compared with ENI and SLI (P&lt;0.05). IFI could significantly reduce relative volume fraction of lungs irradiated more than 5 and 20 Gy (V5 and V20), lungs average dose (Dmean), heart V30, heart Dmean and spinal cord maximum dose (Dmax) (P&lt;0.05), compared with ENI. Lungs V20, lungs Dmean, heart Dmean and spinal cord Dmax decreased by 27.1%, 22.5%, 27.4% and 6.4% compared with ENI, and 24.1%, 22.0%, 24.8% and 5.7% compared with SLI, respectively. After 28 to 69 months of follow-up, 13 patients had recurrence and metastasis, of whom 7 patients had distant metastasis, 4 patients had recurrence in the irradiation field, and 1 patient had local recurrence in the irradiation field. The 3-year overall survival (OS) rate and disease-free survival (DFS) rate were 50.0% and 42.3%, respectively. Conclusion: IFI recommended by our institution is feasible to ensure clinical efficacy while significantly reducing the radiation dose of lungs, heart and spinal cord
    • …
    corecore