后疫情时代大学生在线学习情绪状态和特征分析

关注大学生在线学习情绪发展态势、做好情绪疏导,是后疫情时代高校在线教育创新性发展的重要方向。在线学习情绪分析有助于理解学生的学习状态,为实施有效的在线学习情绪干预提供重要依据。将专业类别、课程类型、学习方式、学习资源纳入大学生在线学习情绪的影响因素,通过问卷调查获取大学生在线学习情绪状态数据,分别分析不同专业类别大学生在线学习情绪状态及主要特征差异。结果发现,大学生在线学习以积极情绪为主,不同专业类别的大学生在学习不同课程类型、使用不同学习方式,以及利用不同学习资源的在线课程时,其在线学习情绪状态均会存在显著性差异。基于此提出以下建议:依据情感需求,设计促进积极情绪的教学模式;灵活运用平台互动工具,提高在线学习参与度和临场感;注重学生情绪认知及管理,发挥教师情感支持作用。

纳米SiO2改性双组分水性聚氨酯的制备及性能

以3-氨丙基三乙氧基硅烷(KH550)接枝改性纳米SiO2,得到氨基化纳米SiO2(改性纳米SiO2),再将其与聚氨酯预聚体反应合成改性聚氨酯多元醇,并与异氰酸酯固化剂固化合成了含改性纳米SiO20%、0.2%、0.4%、0.6%、0.8%、1.0%(质量分数)的双组分水性聚氨酯涂膜和面漆,并以红外光谱(FT-IR)、扫描电镜、透射电镜(TEM)、热重分析、力学性能测试等对产物的结构与性能进行了表征。结果表明,FT-IR证明纳米粒子已经成功以化学键方式接入了聚氨酯中;TEM显示纳米粒子在聚氨酯中分散良好;复合膜力学性能得到大幅改善,当加入量为0.8%时性能达到最佳,由未加改性剂的10MPa增大到28MPa;吸水率从37.7%降低到6.3%;涂膜分解(90%和10%)温度均有所提高;铅笔硬度从HB增大到3H,冲击强度从50kg·cm增大到70kg·cm,表面干燥时间从62min缩短到40min;漆膜硬度达到3H,耐化学腐蚀性良好。

Morphological characteristics and genetic differentiation of Lutraria maxima in coast waters off southeast China

To explore genetic diversity and estimate the genetic differences among populations of Lutraria maxima in the coastal waters off south to southeast China,the morphology of the species of five different geographical populations(Beihai,Weizhou Island,Zhanjiang,Xiamen,and Fuzhou)in Guangxi,Guangdong,and Fujian provinces was studied statistically in combination with the microsatellite markers.As revealed by morphological principal component analysis(PCA),the cumulative contribution rate of the first three principal components was 72.596%.The discrimination accuracy ranged from 47.5%to 80.0%,and the scatter plots of principal component and discriminant analysis were consistent in overall,showing that the Xiamen and Fuzhou populations were overlapped obviously.For microsatellite markers,10 pairs of polymorphic primers were obtained by high-throughput transcriptome sequencing,and used for genetic diversity analysis.It was showed that the average number of alleles and eff ective alleles observed in each population ranged from 8.100 to 10.900,and from 3.497 to 4.228,respectively.The average observed heterozygosity(H_(o))and expected heterozygosity(H_(e))in the five populations ranged from 0.541 to 0.615,and from 0.642 to 0.733,respectively.The genetic distance(DA)ranged from 0.078 to 0.523,and the population genetic differentiation index(F_(ST))ranged from 0.027 to 0.139.The unweighted pair-population method with arithmetic means(UPGMA)and structure analysis showed that the five populations could be divided into two main clusters,the Beibu Gulf group(Beihai and Weizhou Island)and the Southeast China Sea group(Zhanjiang,Xiamen,and Fuzhou),suggesting that L.maxima has been separated geographically by the barrier of the Leizhou Peninsula into two groups in evolution,which provided us with a scientific clue to better protect the bioresource and establish an appropriate fishery management stocks for L.maxima populations in south China.

A New Species of the Asian Leaf Litter Toad Genus Leptobrachella(Amphibia,Anura,Megophryidae)from Chongqing City,Southwest China

Herein we describe a new species,Leptobrachella yunyangensis sp.nov.,from Yunyang County,Chongqing City,China,based on a combination of molecular and morphological data.Phylogenetic analysis based on the mitochondrial 16 S rRNA gene and six nuclear genes indicated that this new species represented an independent evolutionary lineage.The uncorrected genetic distance between the new species and its closest congener species,L.oshanensis,was 5.4 % for 16 S rRNA.The new species can be distinguished from its congeners by a combination of the following characters:(1) moderate body size(SVL28.3-30.6 mm in males);(2) rough dorsal skin,with sparse large granules and tubercles and short longitudinal ridges on the shoulder;(3) distinctly discernible tympanum with a diameter smaller than that of the eye(TMP/EYE ratio:0.51) and a distinct black supra tympanic line present;(4)an internasal distance almost equal to interorbital distance(IND/IOD ratio:1.05);(5) flanks with several dark spots arranged longitudinally in two rows;(6) distinctly visible supra-axilla ry,femoral,pectoral,a nd ventrola teral glands;(7) bicolored iris,with the upper 1/3 of the iris being copper orange and the lower 2/3 a light silvery grey;(8) relative finger lengths of Ⅰ <Ⅱ=Ⅳ <Ⅲ and relative toe lengths of Ⅰ <Ⅱ <Ⅴ <Ⅲ <Ⅳ;(9) absence of webbing and lateral fringes on fingers,and toes with rudimentary webbing and narrow lateral fringes;(10) heels overlapping when the thighs are positioned at right angles to the body;(11) tibiotarsal articulation reaching to the anterior corner of the eye when the leg is stretched forward;(12) ventral surfaces of the throat,chest,and belly greyish white with purple-brown speckling;(13) lacking distinct blackish dorsolateral markings;and(14) transverse dark brown bars on the surfaces of limbs and digits.

Review of regional carbon counting methods for the Chinese major ecological engineering programs

In order to improve environment and relieve poverty, China has launched a series of major ecological engineering programs since the 1980 s. These include the Natural Forest Conservation Program, the Sloping Cropland Conversion Program, the Desertification Combating Program, and the Protection Forest System Construction Program. There is a growing need to quantify the contributions of these programs to regional carbon stocks.However, the lack of widely accepted, robust methods is one of the key obstacles to quantification. The objective of this study was to review existing methods for quantifying regional carbon stocks and then recommend suitable ones for the Chinese ecological engineering programs. We expect that the recommended methods can be applied to elsewhere in the world where there are similar characteristics and objectives.

Seepage Mechanism and Transient Pressure Analysis of Shale Gas

The current research of nonlinear seepage theory of shale-gas reservoir is still in its infancy. According to the characteristics of shale gas in adsorption-desorption, diffusion, slippage and seepage during accumulation, migration and production, a mathematical model of unstable seepage in dual-porosity sealed shale-gas reservoir was developed while considering Knudsen diffusion, slip-flow effect and Langmuir desorption effect. By solving the model utilizing the Stehfest numerical inversion and computer programming in Laplace space, several typical curves of bottomhole pressure were obtained. In this paper, we discussed the effects of several parameters on the pressure dynamics, i.e. storativity ratio, Langmuir volume, Langmuir pressure, adsorption-desorption, tangential momentum accommodation coefficient, flow coefficient, boundary. The results show that the desorbed gas extends the time for fluid to flow from matrix system to fracture system;the changes of Langmuir volume and Langmuir pressure associated with desorption and adsorption effect are the internal causes of the storativity ratio change;when the tangential momentum accommodation coefficient decreases, the time for pressure wave to spread to the border reduces;interporosity flow coefficient determines the occurrence time of the transition stage;boundary range restricts the time for pressure wave to spread to the border.

Test and Evaluation of Aviation Die Tyre Accuracy Based on Industrial Photogrammetry

According to the operational conditions of an aviation module reticule,a measurement mode is proposed,which is based on an industrial photogrammetry system,with matching by a measuring pen.Meanwhile,the factors affecting the accuracy of the measurement have been analyzed and verified by examples.The analysis is described as follows:①Along the optical axis of the camera,the error is larger than the ones in other directions using the“single camera+measuring pen”mode;②By avoiding the error along the optical axis of the camera,the accuracy of the“single camera+measuring pen”mode is better than 0.1 mm when the measuring pen is moving parallel to the optical axis.

优化经直肠前列腺重复穿刺(英文)

Objective: Diagnosis of patients with negative prostate biopsy and persistent suspicion of prostate cancer remains a serious problem. In this study, we investigated the application of optimizing prostate biopsy for patients who need repeat prostate biopsy. Methods: In this prospective, non-randomized phase-I clinical trial, the prostate cancer detection rate of initial detection scheme was compared with optimizing prostate biopsy scheme. The number of punctures of initial detection scheme was the same as that of optimizing prostate biopsy scheme. The puncture direction of optimizing prostate biopsy was a 45° angle to the sagittal plane from front, middle, and back. The two cores from each lateral lobe were horizontally inwardly inclined 45°. Results: A total of 45 patients with initial negative biopsy for cancer were received the optimizing prostate biopsy scheme. The cancer detection rate was 17.8%(8/45), and prostate intraepithelial neoplasm(PIN) was 6.7%(3/45). The patients receiving repeat transrectal prostate biopsies were pathologically diagnosed as lower Gleason grade prostate cancers. Conclusion: The cancer detection rate of repeat biopsy prostate cancer is lower than that of initial biopsy. Our study showed that the optimizing prostate biopsy is important to improve the detection rate of repeat transrectal prostate biopsies patients.

扩大穿刺对PSA≥20ng/mL的患者合适吗?(英文)

Objective: The aim of this study was to investigate whether it was necessary to increase the number of cores at initial prostate biopsy with patients of prostate-specific antigen(PSA) ≥ 20 ng/mL and to explore an appropriate individualized transrectal ultrasonograhpy(TRUS)-guided prostate biopsy for the detection of prostate cancer in men suspicious of prostate cancer. Methods: A total of 115 patients with PSA ≥ 20 ng/mL and suspicious of prostate cancer were prospectively randomized to perform TRUS-guided biopsy. Patients were randomized to a "6 + X" cores or a "10 + X" cores protocol. The primary end point was cancer detection rate. Secondary end points were cancer characteristics, rate of complications and the level of pain experienced by patients during TRUS-guided prostate biopsy. Results: Preoperative variables were similar in both groups. The overall prostate cancer detection rate was 73.9%. The "10 + X" cores strategy increased cancer detection rate only 9.7% in patients with PSA ≥ 20 ng/mL but < 50 ng/mL, while there was no difference between the two strategies for cancer detection in patients with PSA ≥ 50.1 ng/mL. The number of extended biopsy cores and pain score of extended biopsy in prostate cancer patients increased significantly(P < 0.001). Conclusion: Our findings suggest that there is no significant advantage in using extended biopsy protocol in all patients with PSA ≥ 20 ng/mL.