基于S-R和分解定理的二维几何非线性问题的虚单元法求解

应变-旋转(Strain-Rotation,S-R)和分解定理为分析几何非线性问题提供了合理可靠的理论基础,但用有限元求解时会遇到大变形发生后的网格畸变问题。近年提出的虚单元法(Virtual element method,VEM)适用于一般的多边形网格,因此,该文尝试使用一阶虚单元求解基于S-R和分解定理的二维几何非线性问题,以克服网格畸变的影响。基于重新定义的多项式位移空间基函数,推演获得一阶虚单元分析线弹性力学问题时允许位移空间向多项式位移空间的投影表达式;按照虚单元法双线性格式的计算规则,分析处理基于更新拖带坐标法和势能率原理的增量变分方程;进而建立离散系统方程及其矩阵表达形式,并编制MATLAB求解程序;采用常规多边形网格和畸变网格,应用该文算法分析均布荷载下的悬臂梁和均匀内压下的厚壁圆筒变形。结果与已有文献和ANSYS软件的对比表明:该文算法在两种网格中均可有效执行且具备足够数值精度。总体该文算法为基于S-R和分解定理的二维几何非线性问题求解提供了一种鲁棒方法。

Ⅰ导联R/(R+S)对胸前V3导联移行流出道室性心律失常起源部位的鉴别价值

目的:探索鉴别胸前V3导联移行流出道室性心律失常(OT-VA)起源部位的体表心电图指标。方法:连续选择2017年1月至2022年8月行导管射频消融术的胸前V3导联移行OT-VA患者65例。比较左室流出道起源组(LVOT组)和右室流出道起源组(RVOT组)室性心律失常发作时体表心电图QRS波振幅及相关指标的差异,选择差异有统计学意义的指标,绘制ROC曲线评价所选取指标鉴别OT-VA起源部位的效能。结果:LVOT组11例,RVOT组54例,两组间差异有统计学意义且ROC曲线下面积(AUC)最大的指标为Ⅰ导联R波/(R+S)波振幅比[R/(R+S)],其鉴别OT-VA起源部位的AUC(95%CI)为0.949(0.894~1.000),截断值为0.50。Ⅰ导联R/(R+S)<0.50诊断胸前V3导联移行LVOT起源OT-VA的敏感度、特异度和准确度分别为0.909、0.944和0.938。结论:Ⅰ导联R/(R+S)<0.50可准确鉴别LVOT起源的胸前V3导联移行OT-VA。

基于REOF的不同量级降雨侵蚀力时空变化——以重庆市为例

研究重庆市不同地理分区内各量级降雨侵蚀力的时空变化特征,为该地区进行更加精准的区域性水土流失防治工作提供理论依据。选取1981-2020年重庆市31个站点逐日降雨数据,利用旋转经验正交函数(Rotated Empirical Orthogonal Function,REOF)对降雨侵蚀力进行地理分区,并结合R/S、5年滑动平均、Mann-Kendall检验等方法,分析各分区不同量级降雨侵蚀力时空变化。结果表明:①重庆市降雨侵蚀力可分为6个地理区域(Ⅰ-Ⅵ区);②重庆市多年平均降雨侵蚀力为5784.04 MJ·mm/(hm^(2)·h·a),不同降雨侵蚀力从大到小依次为:大雨、暴雨、中雨、大暴雨;③大雨侵蚀力在Ⅰ-Ⅲ区和Ⅴ-Ⅵ区占主导优势,暴雨侵蚀力在Ⅳ区占主导优势。各分区中,中雨、大雨及暴雨侵蚀力主要集中在5-9月,大暴雨侵蚀力集中在6-8月;④各区不同量级降雨侵蚀力年际变化从小到大依次为:中雨、大雨、暴雨、大暴雨;同一量级降雨侵蚀力的整体变化趋势均不显著;Hurst指数表明,中雨侵蚀力在Ⅰ和Ⅴ区、大雨侵蚀力在Ⅱ和Ⅴ区、大暴雨侵蚀力在Ⅰ和Ⅲ区呈强持续上升趋势;⑤中雨、大雨及大暴雨侵蚀力在渝东南、渝东北占主导优势,暴雨侵蚀力在渝西以及重庆中部占主导优势,且Ⅰ区酉阳和秀山、Ⅱ区开州、Ⅲ区北碚和铜梁、Ⅳ区璧山和永川、Ⅴ区巫溪和云阳及Ⅵ区忠县是不同量级降雨侵蚀力的高峰中心。通过对重庆各分区不同量级降雨侵蚀力的分析,明确了可能引起土壤侵蚀的主要雨型、高发时期和潜在风险较高的地区,可为区域水土流失动态监测和水土保持措施的合理制定提供参考。

基于S-O-R模型的视觉营销对消费者购买意愿的影响研究——以红色文创网店为例

为提高红色文创网店的点击转化率,文章从消费者视角出发,研究影响消费者购买意愿的视觉因素。基于S-O-R模型理论,构建红色文创网店视觉营销对消费者购买意愿因素的理论模型。利用S-O-R模型分析了红色文创网店视觉营销中的商品形象、界面形象以及品牌视觉形象对顾客感知价值及顾客购买意向的影响。通过设计量表和调查问卷进行实证研究,并结合结构方程模型加以论证,得出品牌视觉形象和界面形象是影响消费者购买意愿的关键因素,为设计师和红色文创品牌进行网店设计提供了一定的理论参考和建议。

信息性还是娱乐性?——基于S-O-R模型的政务短视频媒介使用及其效果研究

政务短视频是时下较受欢迎的政务新媒体,用户主要在信息性和娱乐性两个维度对其接触和使用。基于S-O-R模型的调查分析表明,政务短视频媒介使用对媒介可信度、用户持续使用意愿主要产生间接影响,且通过政治知识和绩效感知两个变量产生中介效应。其中,政务短视频的使用频率和信息性使用透过政治知识变量对媒介可信度产生显著的正向影响,但娱乐性使用的作用机制为负向。政治知识对用户持续使用意愿的效果路径无显著影响。绩效感知变量是政务短视频使用频率、信息性使用对持续使用意愿产生正向影响的有效中介变量,但对媒介可信度的效果路径无中介作用。说明在视觉化中国政治传播语境中,政务短视频虽不可避免地需要使用娱乐性元素构建内容、获得用户,但根本上仍然要以“信息性”制胜,相应调整内容供给策略和运营策略,以获得积极的效果。

R.S.托马斯诗歌中的反田园书写

R.S.托马斯的诗歌展现了威尔士乡村一系列反田园特质,包括几乎绝望的风景、花园里的机器和自然界弱肉强食的暴力法则。这种现实主义的反田园书写反映了托马斯的民族主义情结、反现代主义和生态主义的立场。通过探讨田园与反田园的含义,分析托马斯诗歌中的反田园书写及其现实关怀,有助于挖掘他积极的入世态度和道德情怀。

达人主播直播带货对消费者购买意愿的双路径影响——基于SOR及ELM模型的分析

文章基于SOR模型和ELM模型,研究了达人主播直播带货营销对消费者购买意愿的影响机理。该研究发现,消费者购买意愿通过中心路径和边缘路径被影响,中心路径因素为信息质量和促销激励,而边缘路径因素为达人主播的专业性、知名度和社会临场感。此外,消费者的感知信任和感知价值对其购买意愿具有显著正向影响,并在不同因素之间起中介作用。本研究结果提供了一个包括感知信任和感知价值双路径的中介影响模型框架,为未来研究该领域提供了新的思路和实证基础。

The Comparison and Contrast of Skopostheorie and Baker's Equivalence Translation Approach

Equivalence can be said to be the central issue in translation although its different approaches have caused heated controversy.However,as early as the 1970s,the Skopostheorie emerged in Germany,and it seemed to challenge the equivalence theories.Although Nida and some linguistics raised some negative problems of this theory,it still rapidly became famous around the world,This article will mainly compare and analyse Skopostheorie and Baker's translation equivalence approach.First,it will give a simple overview of these two approaches.Second,it will discuss the relevant strengths and weaknesses of these two approaches in relation to their usage.Finally,it will discuss combining these two approaches in the same translation.

基于16S rDNA测序分析独活寄生汤对膝骨关节炎大鼠肠道菌群的影响

目的通过16S r DNA测序探讨独活寄生汤(Duhuo Jisheng Decoction,DHJSD)在调控肠道菌群以治疗膝骨关节炎(knee osteoarthritis,KOA)中的潜在机制。方法选取18只SD大鼠,随机分为模型组(关节腔内注射50μL浓度为40 mg/mL的碘乙酸钠)、空白组(灌胃等量生理盐水)以及DHJSD组(造模方法与模型组相同,灌胃独活寄生汤16.5 g/kg),每组6只。造模2周后开始干预,每天灌胃1次,持续4周,并观察其一般情况。给药结束后进行取材,通过HE染色观察软骨变化。ELISA法检测血清白细胞介素(interleukin,IL)-1β、IL-6、IL-17和肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)炎症因子水平。RT-qPCR检测滑膜中核因子κB p65(nuclear factor-κB p65,NF-κB p65)、雷帕霉素靶蛋白(mechanistic target of rapamycin,mTOR)、AMP激活蛋白激酶(AMP-activated protein kinase,AMPK)和磷脂酰肌醇-3-激酶(phosphatidylinositol 3-kinase,PI3K)的相对表达量。取肠道粪便进行16S rDNA测序分析肠道微生物群的差异。结果相比空白组,模型组大鼠的活动减少,毛发失去光泽,摄食量和饮水量减少。相比模型组,DHJSD组大鼠的活动性、毛发光泽和饮食均明显改善。HE染色结果表明,DHJSD能有效改善软骨损伤,减轻纤维化和炎症反应。ELISA结果表明,相比空白组,模型组的IL-1β、IL-6、IL-17和TNF-α水平升高(P<0.01)。相比模型组,DHJSD组IL-1β、TNF-α水平降低(P<0.01)。RT-qPCR结果表明,相比空白组,模型组NF-κB p65、mTOR和AMPK的相对表达量升高(P<0.05)。相比模型组,DHJSD组mTOR的相对表达量降低(P<0.05)。16S r DNA测序结果表明,DHJSD可以调控KOA大鼠的肠道菌群结构,并影响菌群的α和β多样性。乳球菌属(Lactococcus)和肠杆菌属(Enterorhabdus)分别是DHJSD组和模型组中富集最显著的菌群。结论DHJSD能有效修复软骨损伤,减缓KOA的进展,其机制可能与调控肠道菌群、维护肠道屏障完整性以及减少免疫炎症反应有关。

(1R,2S)-2-氟环丙胺对甲苯磺酸盐合成工艺的改进

研究了(1R,2S)-2-氟环丙胺对甲苯磺酸盐的合成工艺。以丁二烯为原料,经过成环、氧化、还原、拆分等反应,设计合成(1S,2S)-2-氟环丙甲酸,通过考察与优化确定了最佳反应条件;进一步制得目标产物(1R,2S)-2-氟环丙胺对甲苯磺酸盐,产物收率达到75%。

基于S-O-R理论的儿童沉浸式美育APP研究与设计

目的针对儿童美育发展不平衡的问题,提升儿童美育产品设计,探究界面上、交互上、内容上可行性和实用性,对儿童美育APP的应用研究提出设计策略和实践探讨。方法基于S-O-R理论,结合心流理论与情感层次理论,提出相关模型,并使用SPSS、AMOS软件进行验证。在假设成立的基础上,观察38名4~14岁儿童操作APP实例,提出儿童美育APP的设计要求。结果认知性、设计类因素等能正向影响儿童美育APP的心流体验、满意度和用户黏性。结论儿童设计区别于成年人设计,提升以儿童为中心的设计,通过优化界面设计、音效、交互设计、核心机制等能有效影响儿童对于产品的沉浸式体验。

碱促进的(3aS,4R,6aR)-双苄基生物素转化为(3aS,4S,6aR)-双苄基生物素的研究

目的:将生物素关键中体(3aS,4S,6aR)-双苄基生物素合成过程中产生的杂质(3aS,4R,6aR)-双苄基生物素经化学反应转化为产物(3aS,4S,6aR)-双苄基生物素。方法:通过碱催化反应,(3aS,4R,6aR)-双苄基生物素能顺利地转化为(3aS,4S,6aR)-双苄基生物素。结果:以异丙醇为溶剂,甲醇钠为催化剂,(3aS,4R,6aR)-双苄基生物素在25℃下搅拌24 h,以32.5%的收率得到(3aS,4S,6aR)-双苄基生物素。结论:该工艺为生物素工业生产中产生的杂质(3aS,4R,6aR)-双苄基生物素的回收利用提供了一种可行的方法。

Comparison of the modified Wiltse’s approach with spinal minimally invasive system and traditional approach for the therapy of thoracolumbar fracture

Thoracolumbar fractures are usually treated by open posterior pedicle screw fixation.However,this procedure involves massive paraspinal muscle stripping,inflicting surgical trauma,and prolonged X-ray exposure.In this study,we observed 127 patients with single-segment injury thoracolumbar fractures.Thirty-six patients were treated by the modified Wiltse’s paraspinal approach with minimally invasive channel system,while 91 patients were treated via traditional posterior approach.Operation time,intraoperative blood loss,intraoperative fluoroscopy frequency,screw placement accuracy,visual analogue scale score,and Cobb’s angle of two groups were compared.The X-ray exposure times were notably reduced(4.2±1.6) in the new approach group(P<0.05).The pedicle screw placement accuracy and Cobb’s angle after surgery were similar in the two groups.We conclude that modified Wiltse’s paraspinal approach w ith spinal minimally invasive channel system surgery can significantly reduce the X-ray exposure times and is an alternative therapy for the thoracolumbar fracture.

Comparison of six statistical approaches in the selection of appropriate fish growth models

The performance of six statistical approaches,which can be used for selection of the best model to describe the growth of individual fish,was analyzed using simulated and real length-at-age data.The six approaches include coefficient of determination(R2),adjusted coefficient of determination(adj.-R2),root mean squared error(RMSE),Akaike's information criterion(AIC),bias correction of AIC(AICc) and Bayesian information criterion(BIC).The simulation data were generated by five growth models with different numbers of parameters.Four sets of real data were taken from the literature.The parameters in each of the five growth models were estimated using the maximum likelihood method under the assumption of the additive error structure for the data.The best supported model by the data was identified using each of the six approaches.The results show that R2 and RMSE have the same properties and perform worst.The sample size has an effect on the performance of adj.-R2,AIC,AICc and BIC.Adj.-R2 does better in small samples than in large samples.AIC is not suitable to use in small samples and tends to select more complex model when the sample size becomes large.AICc and BIC have best performance in small and large sample cases,respectively.Use of AICc or BIC is recommended for selection of fish growth model according to the size of the length-at-age data.

阿富汗地震R/S分形特征及地震活动性分析

地震的发生具有非线性特征,分形理论能够刻画地震时空分布特征及其变化过程。本文基于R/S分析方法确定阿富汗主要地震带的分形特征,利用ARIMA模型对兴都—库什山地震带可能发生的年度最大震级进行预测。R/S分析表明,兴都—库什山地震带Hurst指数为0.9125,地震活动记忆周期为8年;苏莱曼山地震带Hurst指数为0.7281,地震活动记忆周期为9年。兴都—库什山和苏莱曼山地震带地震活动的变化趋势与历史变化一致,且兴都—库什山地震带的趋势延续性比苏莱曼山地震带更为显著。ARIMA模型预测结果显示,2022—2026年兴都—库什山地震带可能发生的年度最大震级分别为M_(b)6.2、M_(b)6.1、M_(b)5.8、M_(b)5.8和M_(b)6.1。

Neomicrocoleus gen.nov.(Microcoleaceae,Oscillatoriales),a novel cyanobacterial genus from benthic mats in a water channel

A new filamentous cyanobacterial strain(CHAB 4127)was successfully isolated from the algal mat during the field investigation of the open channel from Luanhe River to Tianjin,China.The polyphasic approach combining morphological,ultrastructural,ecological,and molecular features was used to characterize this studied strain.The strain is morphologically similar to the Microcoleus-like cyanobacterial taxa under light microscopy,and the radial arrangement of thylakoids is also consistent with that of Microcoleus-like groups.The phylogenetic position of CHAB 4127 based on 16S rRNA gene sequences,is shown to be clearly clustered into an independent clade with the newly established genus Microcoleusiopsis.The maximum similarity of 16S r RNA gene of the studied strain with other existing related cyanobacterial taxa is 93.97%,and the ITS secondary structures is also obviously different from other members of Microcoleaceae.Based on all the above evidence,we proposed the establishment of this novel cyanobacterial genus as Neomicrocoleus,with its type species,Neomicrocoleus tianjinensis.

A molecular mechanics approach for analyzing tensile nonlinear deformation behavior of single-walled carbon nanotubes

In this paper, by capturing the atomic information and reflecting the behaviour governed by the nonlinear potential function, an analytical molecular mechanics approach is proposed. A constitutive relation for single-walled carbon nanotubes （SWCNT＇s） is established to describe the nonlinear stress-strain curve of SWCNT＇s and to predict both the elastic properties and breaking strain of SWCNT＇s during tensile deformation. An analysis based on the virtual internal bond （VIB） model proposed by P. Zhang et al. is also presented for comparison. The results indicate that the proposed molecular mechanics approach is indeed an acceptable analytical method for analyzing the mechanical behavior of SWCNT＇s.

基于S-O-R框架的学科服务平台用户持续使用意愿影响因素研究——以FULink为例

[目的/意义]探究学科服务平台用户持续使用意愿影响因素,并结合用户群组分析进行用户画像,进而为平台更精准化、差异化的服务提供决策依据。[方法/过程]采用问卷调查法收集数据,使用SPSS 26.0对数据进行信效度检验,并使用结构方程模型方法,借助AMOS 23.0进一步对数据进行处理分析。[结果/结论]信息过载、隐私担忧显著正向影响使用倦怠,进而显著负向影响用户对学科服务平台的持续使用意愿。资源推荐、信息质量和互动性显著正向影响心流体验,进而正向影响用户对学科服务平台的持续使用意愿。功能过载对使用倦怠的影响不显著,感知成本直接负向影响用户持续使用意愿,据此提出提升FULink学科服务平台用户持续使用意愿的建议。

Investigation of ductile iron casting process parameters using Taguchi approach and response surface methodology

To find the optimized levels of various casting parameters in the ductile iron casting, various casting defects and the rejection rate were observed from a medium scale foundry. The controlled values of different casting parameters such as pouring temperature, inoculation, carbon equivalent, moisture content, green compression strength, permeability and mould hardness were selected. Three different melts of metal with 0.4wt.%, 0.6wt.%, and 0.8wt.% inoculation （Fe-Si-Mg alloy and post inoculant） were produced using a 1-ton capacity coreless medium frequency induction furnace. L-27 orthogonal array with 3-level settings were chosen for the analysis. Responses for each run were observed. The signal-to-noise （S/N） ratio for each run was calculated using the Taguchi approach, and the optimized levels of different casting parameters were identified based on the SIN ratio. The analysis of variance for the casting acceptance percentage concludes that inoculation is the most significant factor affecting the castings＇ quality with a contribution percentage of 44%; an increase in inoculation results in a significant improvement in acceptance percentage of ductile iron castings. The experiment results showed that with the optimized parameters, the rejection rate was reduced from 16.98% to 6.07%.

Hyperbaric oxygen therapy as a new treatment approach for Alzheimer's disease

Hyperbaric oxygen therapy as a new treatment approach for Alzheimer’s disease（AD）：Alongside the increase in life expectancy,the prevalence of age-related disorders,such as neurodegenerative diseases,is on the rise.For example,AD,the most common form of dementia in the elderly,accounts for 60–80%of all dementia cases.