化学专业课线上学习效果调查及对策研究

在新冠疫情的影响下,线上学习的方式得到了大面积的普及与推广,如今疫情即将结束,线上学习依旧存在于大学生的学习生活中,但其应用并不广泛,根据对湖北师范大学及汉江师范学院化学专业课线上学习情况进行问卷调查,结果分析发现,学生对线上学习的满意度远远小于线下学习,并且线上学习的效果不如线下学习。如何让学生接受线上学习,并使其广泛运用到大学中,本次研究给出以下六点操作性强并保证质量的策略。

On-orbit Geometric Calibration of Linear Push-broom Optical Satellite Based on Sparse GCPs

The paper presents a geometric calibration method based on the sparse ground control points (GCPs), aiming to the linear push-broom optical satellite. This method can achieve the optimal estimate of internal and external parameters with two overlapped image pair along the charge-coupled device (CCD), and sparse GCPs in the image region, further get rid of the dependence on the expensive calibration site data. With the calibrated parameters, the line of sight (LOS) of all CCD detectors can be recovered. This paper firstly establishes the rigorous imaging model of linear push-broom optical satellite based on its imaging mechanism. And then the calibration model is constructed by improving the internal sensor model with a viewing-angle model after an analysis on systematic errors existing in the imaging model is performed. A step-wise solution is applied aiming to the optimal estimate of external and internal parameters. At last, we conduct a set of experiments on the ZY-3 NAD camera and verify the accuracy and effectiveness of the presented method by comparison.

Dynamics of Two Dark Solitons in a Polariton Condensate

We theoretically investigate dynamics of two dark solitons in a polariton condensate under nonresonant pumping,based on driven dissipative Gross–Pitaevskii equations coupled to the rate equation.The equation of motion of the relative center position of two-dark soliton is obtained analytically by using the Lagrangian approach.In particular,the analytical expression of the effective potential between two dark solitons is given.The resulting equation of motion captures how the open-dissipative character of a polariton Bose–Einstein condensate affects properties of dynamics of two-dark soliton,i.e.,two-dark soliton relax by blending with the background at a finite time.We further simulate the relative motion of two dark solitons numerically with the emphasis on how two-soliton motion is manipulated by the initial velocity,in excellent agreement with the analytical results.The prediction of this work is sufficient for the experimental observations within current facilities.

乡村振兴背景下民族地区职业教育的发展策略——基于临夏回族自治州的L校SWOT个案分析

采用SWOT分析法,对我国少数民族地区高等职业教育在其发展的历史进程中长期存在的内部优劣势、外部条件所带来的机会和挑战等问题进行全面详细地分析,将我国少数民族地区高等职业教育在其发展历史进程中的优势、劣势、机遇、威胁性等问题综合了起来,并提出了四种适合我国少数民族地区高等职业教育选择的策略思路。

Fusing Syntactic Structure Information and Lexical Semantic Information for End-to-End Aspect-Based Sentiment Analysis

The aspect-based sentiment analysis(ABSA)consists of two subtasksaspect term extraction and aspect sentiment prediction.Most methods conduct the ABSA task by handling the subtasks in a pipeline manner,whereby problems in performance and real application emerge.In this study,we propose an end-to-end ABSA model,namely,SSi-LSi,which fuses the syntactic structure information and the lexical semantic information,to address the limitation that existing end-to-end methods do not fully exploit the text information.Through two network branches,the model extracts syntactic structure information and lexical semantic information,which integrates the part of speech,sememes,and context,respectively.Then,on the basis of an attention mechanism,the model further realizes the fusion of the syntactic structure information and the lexical semantic information to obtain higher quality ABSA results,in which way the text information is fully used.Subsequent experiments demonstrate that the SSi-LSi model has certain advantages in using different text information.

广泛型牙周炎Ⅲ期C级口腔综合治疗1例

目的:本病例报道1例广泛型牙周炎Ⅲ期C级患者的多学科联合治疗及4年随访。诊治经过:52岁男性患者,进行牙周基础治疗、牙体根管治疗、正畸治疗及种植修复的联合治疗,并接受牙周维护治疗及4年长期随访。结果:经过4年的多学科联合治疗,患者牙周炎症处于静止期,全口咬合趋于协调稳定,缺失牙得到修复。结论:牙周基础治疗和维护治疗对于控制牙周炎症具有重要作用,牙周联合正畸和种植治疗使患者前牙的美观性和后牙的功能性均得到提高,其远期预后较好。

Genomic structure of metabotropic glutamate receptor 7 and comparison of genomic structures of extracellular domains of mGluR family

Metabotropic glutamate receptor 7, coupled with a chemical neurotransmitter L-glutamate, plays an important role in the development of many psychiatric and neurological disorders. To study the biological and genetic mechanism of the mGluR7-related diseases, a physical map covering the full-length mGluR7 genomic sequence has been constructed through seed clone screening and fingerprinting database searching. These BAC clones in the physical map have been sequenced with shotgun strategy and assembled by Phred-Phrap-Consed software; the error rate of the final genoniic sequence is less than 0.01%. mGluR7 spans 880 kb genoniic region, the GC content and repeat content of mGluR7 genoniic sequence are 38% and 37.5% respectively. mGluR7 has a typical 'house-keeping' promoter and consists of 11 exons, with introns ranging from 6 kb to 285 kb. mGluR7a and mGluR7b are two known alternatively splicing variants. Comparing the genomic structures of extracellular domains of mGluR family, their genomic structures can

Enhanced energy-storage performance in BNT-based lead-free dielectric ceramics via introducing SrTi_(0.875)Nb_(0.1)O_(3)

Environmentally friendly lead-free ceramics capacitors,with outstanding power density,rapid charging/discharging rate,and superior stability,have been receiving increasing attention of late for their ability to meet the critical requirements of pulsed power devices in low-consumption systems.However,the relatively low energy storage capability must be urgently overcome.Herein,this work reports on leadfree SrTi_(0.875)Nb_(0.1)O_(3)(STN)replacement of(Bi_(0.47)La_(0.03)Na_(0.5))_(0.94)Ba_(0.06)TiO_(3)(BLNBT)ferroelectric ceramics with excellent energy storage performance.Improving relaxor behaviour and breakdown strength(Eb),decreasing grain size,and mitigating large polarization difference are conductive to the enhancement of comprehensive energy storage performances.The phase-field simulation methods are further analysized evolution process of electrical tree in the experimental breakdown.In particular,the 0.70BLNBT-0.30STN ceramic exhibit a large discharged energy density of 4.2 J/cm^(3) with an efficiency of 89.3%at room temperature under electric field of 380 kV/cm.Additionally,for practical applications,the BLNBT-based ceramics achieve a high power density(~62.3 MW/cm^(3))and fast discharged time(~148.8 ns)over broad temperature range(20-200℃).Therefore,this work can provide a simple and effective guideline paradigm for acquiring high-performance dielectric materials in low-consumption systems operating in a wide range of temperatures and long-term operations.

USP21 deubiquitylates Nanog to regulate protein stability and stem cell pluripotency

The homeobox transcription factor Nanog has a vital role in maintaining pluripotency and self-renewal of embryonic stem cells(ESCs).Stabilization of Nanog proteins is essential for ESCs.The ubiquitin–proteasome pathway mediated by E3 ubiquitin ligases and deubiquitylases is one of the key ways to regulate protein levels and functions.Although ubiquitylation of Nanog catalyzed by the ligase FBXW8 has been demonstrated,the deubiquitylase that maintains the protein levels of Nanog in ESCs yet to be defined.In this study,we identify the ubiquitin-specific peptidase 21(USP21)as a deubiquitylase for Nanog,but not for Oct4 or Sox2.USP21 interacts with Nanog protein in ESCs in vivo and in vitro.The C-terminal USP domain of USP21 and the C-domain of Nanog are responsible for this interaction.USP21 deubiquitylates the K48-type linkage of the ubiquitin chain of Nanog,stabilizing Nanog.USP21-mediated Nanog stabilization is enhanced in mouse ESCs and this stabilization is required to maintain the pluripotential state of the ESCs.Depletion of USP21 in mouse ESCs leads to Nanog degradation and ESC differentiation.Overall,our results demonstrate that USP21 maintains the stemness of mouse ESCs through deubiquitylating and stabilizing Nanog.