Revisit the spin-FET: Multiple reflections, inelastic scattering, and lateral size effects

We revisit the spin-injected field effect transistor (spin-FET) by simulating a lattice model based on recursive lattice Green's function approach. In the one-dimensional case and coherent regime, the simulated results reveal noticeable differences from the celebrated Datta-Das model, which motivate thus an improved treatment and lead to analytic and generalized result. The simulation also allows us to address inelastic scattering (using B\"uttiker's fictitious reservoir approach) and lateral confinement effects on the control of spins which are important issues in the spin-FET device.Comment: 9 pages, 4 figure

An optical fiber tip micrograting thermometer

An ~12 µm long Bragg grating was engraved in an ~5 µm diameter optical fiber tip by focused ion beam (FIB) milling. An ~10-dB extinction was achieved at 1570 nm with only 11 indentations. The grating was used for temperature sensing, and it exhibited a temperature sensitivity of ~22 pm/°C

Design and implementation of wire tension measurement system for MWPCs used in the STAR iTPC upgrade

The STAR experiment at RHIC is planning to upgrade the Time Projection Chamber which lies at the heart of the detector. We have designed an instrument to measure the tension of the wires in the multi-wire proportional chambers (MWPCs) which will be used in the TPC upgrade. The wire tension measurement system causes the wires to vibrate and then it measures the fundamental frequency of the oscillation via a laser based optical platform. The platform can scan the entire wire plane, automatically, in a single run and obtain the wire tension on each wire with high precision. In this paper, the details about the measurement method and the system setup will be described. In addition, the test results for a prototype MWPC to be used in the STAR-iTPC upgrade will be presented.Comment: 6 pages, 10 figues, to appear in NIM

Geological conditions and gas-bearing evaluation of the Niutitang Formation shale in the Xixiang–Zhenba area, China

Black carbonaceous shale of the Niutitang Formation in the Xixiang–Zhenba area was found to be well developed and abundant in high-quality shale gas. However, few studies have been conducted in this area, and its reservoir-forming conditions are not clear. This study aims to analyse source rocks, reservoir characteristics and storage conditions of the Niutitang Formation shale in the Xixiang–Zhenba area using field investigations, drilling and logging, supplemented with laboratory experiments. Results of this study shows that the Niutitang Formation shale is deeply buried at 1500–4500 m and is mainly 10-110 m thick. The shale is widely distributed, thicker in the west, thinner in the east and is a highly mature organic rich source rock with kerogen type I and II. The shale stratum features a high content of brittle minerals, many natural cracks, and a low content of clay minerals which are mainly illite, followed by a mixed layer of illite and smectite. The shale reservoir is characterized by low porosity and permeability. In addition, the lithology is dense and acts as a good seal in this area while it has a high adsorption capacity and high gas-bearing potential. Overall, within the study area, the western, central, and southern parts have good structural preservation conditions. The Niutitang Formation in the study area shows excellent organic matter characteristics for shale gas generation as well as good geological conditions for shale gas accumulation.</p

Instanton Effects in QCD Sum Rules for the 0++0^{++} Hybrid

In this paper, we study instanton contributions to the correlator of the hybrid current $g\bar q \sigma_{\mu\nu}G^a_{\nu\mu}T^a q$. These contributions are then included in a QCD sum-rule analysis of the isoscalar $0^{++}$ hybrid mass. We find a mass at 1.83 GeV for the $(\bar uug+\bar ddg)/\sqrt{2}$ hybrid. However, for the $\bar ssg$ hybrid, we find the sum rules are unstable. We also study non-zero width effects, which affect the mass prediction. The mixing effects between these two states are studied and we find QCD sum rules support the existence of a flavor singlet hybrid with mass at around 1.9 GeV. Finally, we study the mixing effects between hybrid and glueball currents. The mixing between the $(\bar uug+\bar ddg)/\sqrt{2}$($\bar ssg$) and the glueball causes two states, one in the region 1.4-1.8 GeV(1.4-2.2 GeV), and the other in the range 1.8-2.2 GeV(2.2-2.6 GeV).Comment: 12 pages, revised versio

Synthesis of Benzoisoselenazolones via Rh(III)-Catalyzed Direct Annulative Selenation by Using Elemental Selenium

Isoselenazolone derivatives have attracted significant research interest because of their potent therapeutic activities and indispensable applications in organic synthesis. Efficient construction of functionalized isoselenazolone scaffolds is still challenging, and thus new synthetic approaches with improved operational simplicity have been of particular interest. In this manuscript, we introduce a rhodium-catalyzed direct selenium annulation by using stable and tractable elemental selenium. A series of benzamides as well as acrylamides were successfully coupled with selenium under mild reaction conditions, and the obtained isoselenazolones could be pivotal synthetic precursors for several organoselenium compounds. Based on the designed control experiments and X-ray absorption spectroscopy measurements, we propose an unprecedented selenation mechanism involving a highly electrophilic Se(IV) species as the reactive selenium donor. The reaction mechanism was further verified by a computational study.This is the accepted version of the following article: Xu-Xu Q.F., Nishii Y., Uetake Y., et al. Synthesis of Benzoisoselenazolones via Rh(III)-Catalyzed Direct Annulative Selenation by Using Elemental Selenium. Chemistry - A European Journal 27, 17952 (2021); which has been published in final form at https://doi.org/10.1002/chem.202103485. This article may be used for non-commercialpurposes in accordance with the Wiley Self-ArchivingPolicy [https://authorservices.wiley.com/author-resources/Journal-Authors/licensing/self-archiving.html

Decreased density of serotonin 2A receptors in the superior temporal gyrus in schizophrenia - a postmortem study

The superior temporal gyrus (STG) is strongly implicated in the pathophysiology of schizophrenia,particularly with regards to auditory hallucinations. In this study, using in situ quantitative autoradiography in postmortem tissue, we investigated the binding of the [3H]ketanserin to 5-HT2A receptors and [3H] mesulergine to 5-HT2C receptors in the left STG of 8 male schizophrenic patients compared to 8 control subjects. A strong [3H]ketanserin binding was observed in the STG, however there was a very weak [3H] mesulergine binding in the STG. A significant decrease in binding of [3H]ketanserin was clearly observed in schizophrenia patients in comparison with control subjects. There were no significant correlations between 5-HT2A binding density and age, postmortem intervals, or brain pH. These results suggest that the alterations of the 5-HT2A receptors contribute to the pathophysiology of the STG in schizophrenia. Furthermore, there is a clear tendency for a positive correlation between 5-HT2A and muscarinic M1 receptor bindings, and for negative correlations between 5-HT2A and GABAA receptor bindings and between muscarinic M1 and GABAA receptor bindings. This provides a possible mechanism of auditory hallucinations through interactions between 5-HT2A, acetylcholine muscarinic and GABA transmissions in the STG in schizophrenia

FedDCSR: Federated Cross-domain Sequential Recommendation via Disentangled Representation Learning

Cross-domain Sequential Recommendation (CSR) which leverages user sequence data from multiple domains has received extensive attention in recent years. However, the existing CSR methods require sharing origin user data across domains, which violates the General Data Protection Regulation (GDPR). Thus, it is necessary to combine federated learning (FL) and CSR to fully utilize knowledge from different domains while preserving data privacy. Nonetheless, the sequence feature heterogeneity across different domains significantly impacts the overall performance of FL. In this paper, we propose FedDCSR, a novel federated cross-domain sequential recommendation framework via disentangled representation learning. Specifically, to address the sequence feature heterogeneity across domains, we introduce an approach called inter-intra domain sequence representation disentanglement (SRD) to disentangle the user sequence features into domain-shared and domain-exclusive features. In addition, we design an intra domain contrastive infomax (CIM) strategy to learn richer domain-exclusive features of users by performing data augmentation on user sequences. Extensive experiments on three real-world scenarios demonstrate that FedDCSR achieves significant improvements over existing baselines

The preparation and properties of novel structural carbon foams derived from different mesophase pitches

As a novel porous multi-functional carbon material, carbon foams have high bulk thermal conductivity and low density, making them as excellent materials for thermal management systems applications, such as heat exchangers, space radiators, and thermal protection systems. In this paper, the carbon foams with high thermal conductivity, derived from three kinds of mesophase pitches, were fabricated by the process of foaming, carbonization and graphitization. The microstructures of the foams were examined by scanning electron microscopy. It was found that the pores were uniformly distributed, and the pore wall thickened with increasing foams’ density. The properties of the foams were studied, including compressive strength and thermal conductivity. The results showed that lower density and higher thermal conductivity were achieved for the foams using the two kinds of pitches with higher volatile components. The bulk thermal conductivity of carbon foams were up to 179 W/(m·K) and 201 W/(m·K), for the densities of 0.66 g/cm3 and 0.83 g/cm3, respectively. The foams’ compressive strength was in the range of 1.6 MPa to 3.4 MPa

Disorder induced field effect transistor in bilayer and trilayer graphene

We propose use of disorder to produce a field effect transistor (FET) in biased bilayer and trilayer graphene. Modulation of the bias voltage can produce large variations in the conductance when the disorder's effects are confined to only one of the graphene layers. This effect is based on the bias voltage's ability to select which of the graphene layers carries current, and is not tied to the presence of a gap in the density of states. In particular, we demonstrate this effect in models of gapless ABA-stacked trilayer graphene, gapped ABC-stacked trilayer graphene, and gapped bilayer graphene.Comment: 21 pages, 7 figure