高校科普资源助推“双减”工作的实践与探索

介绍了南京大学在“双减”政策背景下与中小学深度合作开展科普工作的具体做法。科普基地确立了“弘扬科学精神、科普活动与课内教育深度融合、以学生为中心”的原则,所有的科普教育活动都根据这些原则来设计。总结了在资源开放、师资供给、课程开发等方面的一些经验。

营商环境驱动的城市经济发展前因组态研究——基于长三角城市数据挖掘的fsQCA分析

为揭示城市经济发展前因条件的组态效应,本文以长三角为样本,运用主成分分析法(PCA)进行因子提取,构建了六个区域经济发展影响因子指数,并采用fsQCA分析了城市文化娱乐业繁荣度、城市生活和房地产繁荣程度、城市科技化水平、城市制造业依赖度、城市农业依赖度、城市个私经济繁荣程度等前因条件对城市人均GDP作用机制。研究发现:城市人均GDP提升的本质为多因素的耦合与协同,具有多元化的模式和多条路径。城市农业依赖度和个私经济繁荣程度为核心条件,城市科技化水平作为边缘条件的营商环境要素组合,以及城市农业依赖度、城市个私经济繁荣程度作为核心条件,城市文化娱乐业繁荣度、城市生活和房地产繁荣程度、城市科技化水平作为辅助条件,是提升城市人均GDP的前因条件。而且发现,这两种路径都是以城市农业依赖度和个私经济繁荣程度为核心条件,分析认为这可能与长三角经济发展的历史渊源有关。本文拓展和丰富了区域营商环境影响因素理论研究,也为进一步优化区域经济发展政策提供了建议。

乳液成型制备二氧化硅/聚四氟乙烯复合薄膜及其性能优化

聚四氟乙烯(PTFE)由于优异的介电性能已成为高频通讯的重要载体,通常将其与无机填料复配以提高其力学性能。但是,受限于PTFE极低的表面能,无机填料与其界面作用极差,难以在传统车削或压延成膜的强应力作用下实现高填充复合薄膜材料的成型。因此文中尝试以尺寸更小,界面可灵活构筑的PTFE乳液为基体、二氧化硅(SiO_(2))为无机填料,通过SiO_(2)表面改性对SiO_(2)/PTFE复合膜材料性能强化,研究无机粒子表面改性对复合材料分散、界面及力学性能等的影响。研究发现,当偶联剂质量分数为5%时,SiO_(2)/PTFE复合薄膜(80μm)力学性能最优,拉伸强度由SiO_(2)改性前的4.35 MPa增加至5.33 MPa、断裂伸长率由38.2%增加至134.0%。为提高PTFE/SiO_(2)界面强度、制备高性能PTFE复合薄膜材料提供了新方法。

基于同步提取变换和脊线检测的空间锥体目标微多普勒特征提取方法

针对空间锥体目标微多普勒(micro-Doppler,m-D)提取时在m-D曲线交叉处易出现跟踪错误的问题,提出一种基于同步提取变换(synchro-extracting transform,SET)和脊线检测的m-D特征提取方法。首先,该方法利用SET技术得到能量分布更加集中的时频像,并使用Hough变换提取锥体顶部产生的正弦m-D曲线;之后基于CLEAN思想,将提取到的顶部m-D曲线从时频像中消除;最后利用基于改进疯爬算法和卡尔曼滤波的脊线检测算法提取锥体底部产生的非正弦m-D曲线。仿真结果表明,该方法可以避免m-D曲线交叉处的跟踪错误问题,正确提取m-D特征。

Control method based on DRFNN sliding mode for multifunctional flexible multistate switch

To address the low accuracy and stability when applying classical control theory in distribution networks with distributed generation,a control method involving flexible multistate switches(FMSs)is proposed in this study.This approach is based on an improved double-loop recursive fuzzy neural network(DRFNN)sliding mode,which is intended to stably achieve multiterminal power interaction and adaptive arc suppression for single-phase ground faults.First,an improved DRFNN sliding mode control(SMC)method is proposed to overcome the chattering and transient overshoot inherent in the classical SMC and reduce the reliance on a precise mathematical model of the control system.To improve the robustness of the system,an adaptive parameter-adjustment strategy for the DRFNN is designed,where its dynamic mapping capabilities are leveraged to improve the transient compensation control.Additionally,a quasi-continuous second-order sliding mode controller with a calculus-driven sliding mode surface is developed to improve the current monitoring accuracy and enhance the system stability.The stability of the proposed method and the convergence of the network parameters are verified using the Lyapunov theorem.A simulation model of the three-port FMS with its control system is constructed in MATLAB/Simulink.The simulation result confirms the feasibility and effectiveness of the proposed control strategy based on a comparative analysis.

Knock-out of GhPDCT with the CRISPR/Cas9 system increases the oleic acid content in cottonseed oil

Cotton is a pivotal economic crop for natural textile fibers that also serves as an important source of edible oil(Long et al.2023).Cottonseed oil contains approximately14%oleic acid and 59%linoleic acid.An increase in monounsaturated fatty acids,particularly oleic acid,enhances the oxidative stability and nutritional value of edible oil(Chen et al.2021).

Fine-mapping and primary analysis of candidate genes associated with seed coat color in mung bean(Vigna radiata L.)

Seed coat color affects the appearance and commodity quality of mung beans(Vigna radiata L.).The substances that affect mung bean seed coat color are mainly flavonoids,which have important medicinal value.Mapping the seed coat color gene in mung beans would facilitate the development of new varieties and improve their value.In this study,an F2 mapping population consisting of 546 plants was constructed using Jilv9(black seed coat)and BIS9805(green seed coat).Using bulk segregated analysis(BSA)sequencing and kompetitive allele-specific PCR(KASP)markers,the candidate region related to seed coat color was finally narrowed to 0.66 Mb on chromosome(Chr.)4 and included eight candidate genes.Combined transcriptome and metabolome analyses showed that three of the eight candidate genes(LOC106758748,LOC106758747,and LOC106759075)were differentially expressed,which may have caused the differences in flavonoid metabolite content between Jilv9 and BIS9805.These findings can provide a research basis for cloning the genes related to seed coat color and accelerate molecular markerassisted selection breeding in mung beans.

Identification of P-type plasma membrane H^(+)-ATPases in common wheat and characterization of TaHA7 associated with seed dormancy and germination

The P-type plasma membrane(PM)H^(+)-ATPases(HAs)are crucial for plant development,growth,and defense.The HAs have been thoroughly characterized in many different plants.However,despite their importance,the functions of HAs in germination and seed dormancy(SD)have not been validated in wheat.Here,we identified 28 TaHA genes(TaHA1-28)in common wheat,which were divided into five subfamilies.An examination of gene expression in strong-and weak-SD wheat varieties led to the discovery of six candidate genes(TaHA7/-12/-14/-16/-18/-20).Based on a single nucleotide polymorphism(SNP)mutation(C/T)in the TaHA7 coding region,a CAPS marker(HA7)was developed and validated in 168 wheat varieties and 171 Chinese mini-core collections that exhibit diverse germination and SD phenotypes.We further verified the roles of the two allelic variations of TaHA7 in germination and SD using wheat mutants mutagenized with ethyl methane sulphonate(EMS)in‘Jimai 22’and‘Jing 411’backgrounds,and in transgenic Arabidopsis lines.TaHA7 appears to regulate germination and SD by mediating gibberellic acid(GA)and abscisic acid(ABA)signaling,metabolism,and biosynthesis.The results presented here will enable future research regarding the TaHAs in wheat.

High-throughput microfluidic production of carbon capture microcapsules:fundamentals,applications,and perspectives

In the last three decades,carbon dioxide(CO_(2)) emissions have shown a significant increase from various sources.To address this pressing issue,the importance of reducing CO_(2) emissions has grown,leading to increased attention toward carbon capture,utilization,and storage strategies.Among these strategies,monodisperse microcapsules,produced by using droplet microfluidics,have emerged as promising tools for carbon capture,offering a potential solution to mitigate CO_(2) emissions.However,the limited yield of microcapsules due to the inherent low flow rate in droplet microfluidics remains a challenge.In this comprehensive review,the high-throughput production of carbon capture microcapsules using droplet microfluidics is focused on.Specifically,the detailed insights into microfluidic chip fabrication technologies,the microfluidic generation of emulsion droplets,along with the associated hydrodynamic considerations,and the generation of carbon capture microcapsules through droplet microfluidics are provided.This review highlights the substantial potential of droplet microfluidics as a promising technique for large-scale carbon capture microcapsule production,which could play a significant role in achieving carbon neutralization and emission reduction goals.

Tuning the surface electronic structure of noble metal aerogels to promote the electrocatalytic oxygen reduction

The sluggish kinetics of the oxygen reduction reaction(ORR)is the bottleneck for various electrochemical energy conversion devices.Regulating the electronic structure of electrocatalysts by ligands has received particular attention in deriving valid ORR electrocatalysts.Here,the surface electronic structure of Ptbased noble metal aerogels(NMAs)was modulated by various organic ligands,among which the electron-withdrawing ligand of 4-methylphenylene effectively boosted the ORR electrocatalysis.Theoretical calculations suggested the smaller energy barrier for the transformation of O^(*) to OH^(*) and downshift the d-band center of Pt due to the interaction between 4-methylphenylene and the surface metals,thus enhancing the ORR intrinsic activity.Both Pt3Ni and Pt Pd aerogels with 4-methylphenylene decoration performed significant enhancement in ORR activity and durability in different media.Remarkably,the 4-methylphenylene modified Pt Pd aerogel exhibited the higher halfwave potential of 0.952 V and the mass activity of 10.2 times of commercial Pt/C.This work explained the effect of electronic structure on ORR electrocatalytic properties and would promote functionalized NMAs as efficient ORR electrocatalysts.

A novel cascaded H-bridge photovoltaic inverter with flexible arc suppression function

This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding faults.Inverters compensate for ground currents through an arc-elimination function,while outputting a PV direct current(DC)power supply.This method effectively reduces the residual grounding current.To reduce the dependence of the arc-suppression performance on accurate compensation current-injection models,an adaptive fuzzy neural network imitating a sliding mode controller was designed.An online adaptive adjustment law for network parameters was developed,based on the Lyapunov stability theorem,to improve the robustness of the inverter to fault and connection locations.Furthermore,a new arc-suppression control exit strategy is proposed to allow a zerosequence voltage amplitude to quickly and smoothly track a target value by controlling the nonlinear decrease in current and reducing the regulation time.Simulation results showed that the proposed method can effectively achieve fast arc suppression and reduce the fault impact current in single-phase grounding faults.Compared to other methods,the proposed method can generate a lower residual grounding current and maintain good arc-suppression performance under different transition resistances and fault locations.

大学《无机化学》课堂的教学方法探究

当前社会各行各业都处于飞速发展之中,对人才的需求也发生了变化,因此对人才培养策略提出了新的要求。无机化学是众多大学专业的基础课程,其中包括化工技术、药学、医学、环境等,学好这门课程有利于提升学生的专业素养,从而为社会诸多领域输送人才。因此,提升这门课程的教学质量和教学效果至关重要。本文分析了大学无机化学课程体系的特点和教学现状,并对该课程的课堂教学方法进行了探究。

Lift-Off Effect of Koch and Circular Differential Pickup Eddy Current Probes

A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of defects.However,the extent of the lift-off effect on differential probes,including different coil structures,varies.In this study,two planar eddy current probes with differential pickup structures and the same size,Koch and circular probes,were used to compare lift-off effects.The eddy current distributions of the probes perturbed by 0°and 90°cracks were obtained by finite element analysis.The analysis results show that the 90°crack can impede the eddy current induced by the Koch probe even further at relatively low lift-off distance.The peak-to-peak values of the signal output from the two probes were compared at different lift-off distances using finite element analysis and experimental methods.In addition,the effects of different frequencies on the lift-off were studied experimentally.The results show that the signal peak-to-peak value of the Koch probe for the inspection of cracks in 90°orientation is larger than that of the circular probe when the lift-off distance is smaller than 1.2 mm.In addition,the influence of the lift-off distance on the peak-to-peak signal value of the two probes was studied via normalization.This indicates that the influence becomes more evident with an increase in excitation frequency.This research discloses the lift-off effect of differential planar eddy current probes with different coil shapes and proves the detection merit of the Koch probe for 90°cracks at low lift-off distances.

Predicting the Mechanical Behavior of a Bioinspired Nanocomposite through Machine Learning

The bioinspired nacre or bone structure represents a remarkable example of tough,strong,lightweight,and multifunctional structures in biological materials that can be an inspiration to design bioinspired high-performance materials.The bioinspired structure consists of hard grains and soft material interfaces.While the material interface has a very low volume percentage,its property has the ability to determine the bulk material response.Machine learning technology nowadays is widely used in material science.A machine learning model was utilized to predict the material response based on the material interface properties in a bioinspired nanocomposite.This model was trained on a comprehensive dataset of material response and interface properties,allowing it to make accurate predictions.The results of this study demonstrate the efficiency and high accuracy of the machine learning model.The successful application of machine learning into the material property prediction process has the potential to greatly enhance both the efficiency and accuracy of the material design process.

Effect of surgical timing on postoperative outcomes in patients with acute cholecystitis after delayed percutaneous transhepatic gallbladder drainage

BACKGROUND To date,the optimal timing for percutaneous transhepatic gallbladder drainage(PTGBD),particularly for patients who have missed the optimal window for emergency laparoscopic cholecystectomy(LC)(within 72 hours of symptom onset)has not been determined.AIM To study the effects of LC timing on outcomes of grade II/III acute cholecystitis(AC)in patients with delayed PTGBD.METHODS Data of patients diagnosed with Tokyo Guidelines 2018 grade II or III AC who underwent delayed PTGBD followed by LC at a single hospital between 2018 and 2022 were retrospectively studied.According to the interval between gallbladder drainage and cholecystectomy,the patients were divided into early and delayed LC groups.Outcomes including surgery time,postoperative complications and hospital stay,and patient satisfaction were analyzed and compared between the two groups using t-andχ^(2) tests.RESULTS There were no significant differences between the two groups in intraoperative blood loss,postoperative abdominal drainage tube placement time,pain index,or total disease duration(all P>0.05).Compared with those of the early LC group,the delayed group showed significant decreases in the length of procedure(surgery time),conversion rate to open surgery,degree of adhesions,surgical complications,postoperative hospital stay,and total treatment costs,and increased patient satisfaction despite a longer interval before PTGBD(all P<0.05).CONCLUSION For patients with grade II/III AC with delayed PTGBD,LC should be performed 2 weeks after PTGBD to decrease postoperative complications and hospital stays and improve patient satisfaction.

大学有机化学课程中思政元素的挖掘与教学策略

在当今高等教育体系中,课程思政已成为提升大学生综合素质、培养全面发展人才的重要途径。有机化学作为化学学科的重要分支,不仅承载着传授专业知识与技能的使命,还蕴含着丰富的思政教育资源。然而,如何在有机化学课程中有效挖掘并利用这些思政元素,实现专业知识传授与价值引领的有机统一,是值得教育工作者深入探讨的重要课题。对此,本文通过阐述在大学有机化学课程中挖掘思政元素的必要性,分析大学有机化学课程中思政元素的挖掘策略,在此基础上探究大学有机化学课程中思政元素的教学策略,以期实现专业知识与思政教育的有机结合,促进学生全面发展。

“双减”深化期如何提升教师参与课后服务的积极性?——基于四省中小学教师调查的实证研究

教师是课后服务的实施主体,亦是保障课后服务质量的关键。为提升教师课后服务参与的积极性,探究其参与课后服务意愿的影响因素,对我国中西南北四省中小学教师参与课后服务意愿的调查发现:教师参与课后服务意愿处于中等水平;教师通过“服务学生获得精神满足”与“学生获得能力提升”的“结果期望”两个激励因素正向影响其参与意愿;“获得课后服务津贴”这一保健因素显著提升其参与意愿,“引入校外师资”降低在职教师参与意愿。其他特征如教师性别、教龄、学校性质与所处学段也显著影响其参与意愿。基于实证发现,提出如下建议:建立课后服务激励机制,激发教师教学活力;优化课后服务管理制度,落实弹性上下班制;夯实课后服务教研活动,多方协同合作教学;重视课后服务成果评价,促进教学评一体化。

翻转课堂在外国留学生皮肤性病科见习课中的应用

目的 探讨翻转课堂在临床医学本科外国留学生皮肤性病科见习课中的教学效果。方法 选取我校2017级临床医学本科全英班72名外国留学生,随机分为对照组和实验组各36名。对照组采用传统方法教学,实验组采用翻转课堂教学,观察比较两组的教学效果。结果 与对照组比较,实验组学生对翻转课堂教学法的认可度较高,在主动学习能力、文献查找能力、汇报表达能力及团队合作能力的自我评价方面明显优于对照组,差异均有统计学意义(均P<0.05)。两组学生在病史采集、体格检查及皮肤科查体得分方面比较,差异均无统计学意义(均P>0.05);在疾病诊断、诊断依据及鉴别诊断、诊疗计划方面得分比较,实验组均高于对照组,差异均有统计学意义(均P<0.05)。结论 翻转课堂教学法可有效提高外国留学生在皮肤性病学见习课的教学效果。

撼地者:基于遥操作与自主导航的移动救援机器人

为了应对突发场景及灾难环境下的救援作业任务,避免救援人员暴露在危险环境中,本论文提出一款移动救援机器人,“撼地者”。凭借履带式底盘、六自由度灵巧机械臂及各种传感器及控制器的组合,撼地者得以拥有跨越多样地形和完成精细作业的能力。具体来说,首先,撼地者独特的摆臂-推铲机构设计,在提高了清障能力的同时,增加了上下楼梯的稳定性;其次,通过多模态遥操作系统使撼地者得以适应各种复杂的通讯环境;同时,基于深度相机辅助的灵巧机械臂与抓手实现了半自主操纵;最终,利用激光雷达实现了在未知环境中的自主导航。正是凭借这些特别的系统,撼地者在以应急救援为主题的“智创杯”前沿技术挑战赛锦标赛中,从全球40个机器人中脱颖而出并成功夺冠,展示了其系统集成的有效性及控制理念的先进性。

从燃烧热测量求算化学反应热——“燃烧热的测定”实验改进

经典物理化学实验“燃烧热的测定”主要涉及化学热力学中燃烧热知识点,为典型的验证性实验。本实验改进结合重要化学品邻苯二甲酸(酐)的生产过程,通过测量萘、邻二甲苯、邻苯二甲酸和邻苯二甲酸酐等几种物质的燃烧热,计算其合成过程的反应热,既丰富了燃烧热实验的内容,又能和实际应用相关联。实验涉及几种原料廉价易得,均可测得准确的燃烧热数值,进而能获得可靠的反应热结果。采用线上、线下相结合的翻转学习教学模式,再通过几个反应过程测量的分工合作,可以有效地培养和提升学生的自主学习能力和团队协作精神。