Layered Structural PBAT Composite Foams for Efficient Electromagnetic Interference Shielding

The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable manufacturing.In this work,magnetic poly(butyleneadipate-coterephthalate)(PBAT)microspheres were firstly synthesized via phase separation method,then PBAT composite foams with layered structure was constructed through the supercritical carbon dioxide foaming and scraping techniques.The merits of integrating ferroferric oxideloaded multi-walled carbon nanotubes(Fe3O4@MWCNTs)nanoparticles,a microcellular framework,and a highly conductive silver layer have been judiciously orchestrated within this distinctive layered configuration.Microwaves are consumed throughout the process of“absorption-reflection-reabsorption”as much as possible,which greatly declines the secondary radiation pollution.The biodegradable PBAT composite foams achieved an EMI shielding effectiveness of up to 68 dB and an absorptivity of 77%,and authenticated favorable stabilization after the tape adhesion experiment.

Stable photocurrent-voltage characteristics of perovskite single crystal detectors obtained by pulsed bias

Photocurrent-voltage characterization is a crucial method for assessing key parameters in x-ray or y-ray semiconductor detectors,especially the carrier mobility lifetime product.However,the high biases during photocurrent measurements tend to cause severe ion migration,which can lead to the instability and inaccuracy of the test results.Given the mixed electronic-ionic charac teristics,it is imperative to devise novel methods capable of precisely measuring photocurrentvoltage characteristics under high bias conditions,free from interference caused by ion migration.In this paper,pulsed bias is employed to explore the photocurrent-voltage characteristics of MAPbBr_(3) single crystals.The method yields stable photocurrent-voltage characteristics at a pulsed bias of up to 30 V,proving to be effective in mitigating ion migration.Through fitting the modified Hecht equation,we determined the mobility lifetime products of 1.0×10^(2) cm^(2)·V^(-1)for hole and 2.78×10~(-3)cm^(2)·V^(-1)for electron.This approach offers a promising solution for accurately measuring the transport properties of carriers in perovskite.

Effectivity and safety of trifocal intraocular lenses and capsular tension rings implantation for cataract patients with axial high myopia

●AIM:To assess effectivity and safety of trifocal intraocular lenses(IOLs)and capsular tension rings in treating cataract patients with axial high myopia.●METHODS:A prospective nonrandomized controlled clinical trial was conducted.Totally 98 eyes(74 patients)who underwent femtosecond laser-assisted cataract surgery(FLACS)with trifocal IOLs were enrolled in the study and followed up for 2y after surgery:46 eyes(33 patients)with capsular tension ring implantation in the long axial lengths(AL)group(26<AL<29 mm)and 52 eyes(41 patients)in the normal AL group(22<AL<24.5 mm).Postoperative outcomes about effectivity and safety,including the subjective and objective visual quality,and postoperative complications were assessed.●RESULTS:Uncorrected distance visual acuity at 5 m and uncorrected intermediate visual acuity at 60 and 80 cm in the long AL group were significantly worse than those in the normal AL group at 3mo postoperatively(P<0.05).The differences in reading speed,spectacle independence and potential visual complaints between the two groups were not statistically significant(P>0.05).The dysfunctional lens index and total modulation transfer function(MTF)average height were similar between the two groups.The postoperative internal coma aberrations in the axial high myopia eyes were significantly higher than that in the normal AL group(P<0.05).The total satisfaction score in the long AL group(91.32±2.76)was slightly higher than that in the normal AL group(90.36±3.47),but there was no difference(P=0.136).A statistically negative correlation was found between corrected distance visual acuity(CDVA)and dysfunctional lens index(r=-0.382,P=0.009),and between CDVA and the total MTF average height(r=-0.374,P=0.01).But there was no significant correlation between CDVA and total satisfaction score(r=0.059,P=0.696).Postoperative complications mainly presented as posterior capsular opacity(PCO),retinal detachment and cystoid macular edema.There was no difference in the incidence of fundus disease(6.5%vs 3.8%,P=0.663)or PCO(17.4%vs 7.7%,P=0.217)between the two groups at two years.●CONCLUSION:The utilization of trifocal IOL and capsular tension ring implantation is beneficial for cataract patients with axial high myopia undergoing FLACS.This approach not only ensures excellent subjective feelings and objective visual quality,but also does not increase the incidence of postoperative complications.

Public Sentiment Analysis of Social Security Emergencies Based on Feature Fusion Model of BERT and TextLevelGCN

At present, the emotion classification method of Weibo public opinions based on graph neural network cannot solve the polysemy problem well, and the scale of global graph with fixed weight is too large. This paper proposes a feature fusion network model Bert-TextLevelGCN based on BERT pre-training and improved TextGCN. On the one hand, Bert is introduced to obtain the initial vector input of graph neural network containing rich semantic features. On the other hand, the global graph connection window of traditional TextGCN is reduced to the text level, and the message propagation mechanism of global sharing is applied. Finally, the output vector of BERT and TextLevelGCN is fused by interpolation update method, and a more robust mapping of positive and negative sentiment classification of public opinion text of “Tangshan Barbecue Restaurant beating people” is obtained. In the context of the national anti-gang campaign, it is of great significance to accurately and efficiently analyze the emotional characteristics of public opinion in sudden social violence events with bad social impact, which is of great significance to improve the government’s public opinion warning and response ability to public opinion in sudden social security events. .

An Analysis of the Evolution of Online Public Opinion on Public Health Emergencies by Combining CNN-BiLSTM + Attention and LDA

In this paper, the Foxconn epidemic event in Zhengzhou was taken as an example to analyze the evolution of online public opinion on public health emergencies. In order to improve the performance of online public opinion analysis, based on the life cycle theory and LDA theory, the emotional changes of Internet users in four stages of the Foxconn incident centered on the evolution of inscription were divided. The emotions of netizen speech at different stages are analyzed based on CNN-BiLSTM + Attention model, which uses Convolutional Neural Network (CNN) to extract local features. Bi-directional Long Short-Term Memory (BiLSTM) is used to efficiently extract contextual semantic features and long distance dependencies, and then combined with attention mechanism to add emotional features. Finally, Softmax classifier realizes text emotion prediction. The experimental results show that: compared with TextCNN, BiLSTM, BiLSTM + Attenion, CNN-BiLSTM model, the emotion classification model has better effects in the accuracy rate, accuracy rate, recall rate and F value. By analyzing the emotional distribution and evolution trend of public opinion under “text topic”, the paper accurately deconstructs the development characteristics of public opinion in public health emergencies, in order to provide reference for relevant departments to deal with public opinion in public health emergencies. .

Research on Prediction of Sentiment Trend of Food Safety Public Opinion

Emotion has a nearly decisive role in behavior, which will directly affect netizens’ views on food safety public opinion events, thereby affecting the development direction of public opinion on the event, and it is of great significance for food safety network public opinion to predict emotional trends to do a good job in food safety network public opinion guidance. In this paper, the dynamic text representation method XLNet is used to generate word vectors with context-dependent dependencies to distribute the text information of food safety network public opinion. Then, the word vector is input into the CNN-BiLSTM network for local semantic feature and context semantic extraction. The attention mechanism is introduced to give different weights according to the importance of features, and the emotional tendency analysis is carried out. Based on sentiment analysis, sentiment value time series data is obtained, and a time series model is constructed to predict sentiment trends. The sentiment analysis model proposed in this paper can well classify the sentiment of food safety network public opinion, and the time series model has a good effect on the prediction of food safety network public opinion sentiment trend. .

中医特色疗法对妊娠剧吐有效性的网状Meta分析

目的应用网状Meta分析评价中医特色治疗妊娠剧吐的有效性。方法检索从建库到2022年2月28日收录的中医特色治疗妊娠剧吐的随机对照试验,根据Cochrane偏倚风险评估工具对所筛选的文献进行质量评价,应用RevMan 5.3软件生成偏倚风险评估报告,Stata 13.1软件对数据进行统计分析及图形绘制。结果共纳入24篇文献,1660例患者,累计概率排序图(SUCRA)排序依次为:针刺>穴位按摩>艾灸>穴位注射>穴位贴敷>耳穴压豆>常规西医。结论6种中医特色治疗均优于单独常规西医治疗,且针刺疗效最佳。

An overview of the geology and production of the Fuling shale gas field,Sichuan Basin,China

The Fuling shale gas field in China is the largest shale gas field as well as the largest of its type discovered in any Lower Paleozoic formation.In this study,the geology and production of the upper and lower gas layers in the Fuling shale gas field are evaluated in terms of structure,shale quality,fault,initial production,and estimated ultimate recovery(EUR).The shale in the lower gas layer of the Jiaoshiba anticline is a high-quality reservoir,where the space is dominated by organic pores in kerogen,and the gas content is high.The shale gas wells reveal relatively high initial production and EUR.However,the shale in the upper gas layer of the Jiaoshiba anticline has reservoir space mainly composed of clay mineral pores and organic pores within bitumen,and the gas content is low.In terms of structure,primary gas migration may occur in the upper gas layer,resulting in free gas accumulation in the structural high,where the development effects are generally better than those in the structural low.The lower gas layer in the Pingqiao anticline,is the main interval for shale gas accumulation and development due to the high-quality shale.Under the influence of faults,the efficiency of exploration wells emplaced on top of the anticline is much lower a compared with those in the flanks.The residual synclines close to the Sichuan Basin,including the Baima and Baitao anticlines,are characterized by more recent uplifts,larger area,greater distance from the deep and large faults,and early fracture closure.Therefore,we recommend that the shale gas exploration and development should be carried out preferentially in areas close to the center of the residual synclines,featuring relatively high-pressure coefficient and moderate burial depth.

增材制造用新型镍基高温合金的设计与开发

为了满足增材制造专用镍基高温合金成分优化设计需求,采用机器学习(machine learning, ML)和抗裂因子筛选相结合的综合设计策略开发了新型镍基高温合金。热力学计算结果表明,该合金凝固温度范围窄,在临界温度区间内凝固速度快,且收缩总应变及最大应变速率很小,表现出良好的凝固特性。利用选区激光熔化技术制备了新型合金,在成形试样的纵截面和横截面金相中未发现明显裂纹,合金表现出良好的抗裂性能。通过热处理工艺优化,合金在900℃时效后γ′相分数达到44.6%,组织内未见任何TCP相析出,实现了镍基高温合金在增材制造中抗裂性与力学性能的平衡。提出的综合设计策略可为增材制造领域中新材料的快速研发提供新的思路。

基于自适应TQWT与小波包奇异谱熵的滚动轴承早期故障诊断

滚动轴承早期故障诊断可有效地保证机械设备的运行安全,针对滚动轴承早期故障特征微弱,故障特征提取不佳的问题,提出可调品质因子小波变换(Tunable Q-factor wavelet transform,TQWT)与小波包奇异谱熵相结合提取特征的滚动轴承早期故障诊断方法。针对滚动轴承早期故障信号的冲击性与周期性特征,提出峭谱积(峭度和包络谱峰值因子的乘积,KEc)的新指标。以KEc为优化指标,采用网格搜索法确定TQWT最佳的品质因子Q,同时以中心频率比为优化指标,确定最佳的分解层数J。通过最佳参数Q和J对原始信号进行TQWT分解并单支重构,选择KEc最大的重构分量作为最佳分量。提取最佳分量的小波包奇异谱熵值作为故障特征向量,最后运用支持向量机(SVM)进行模式识别并进行早期故障诊断。为验证所提方法的有效性,以XJTU-SY滚动轴承加速寿命试验平台研究对象,运用加速度传感器获取的试验数据集进行验证,识别结果准确率为94.5%。同时,与优化指标为峭度等的SVM识别结果进行比较,所提方法识别率提高了约1%~7%。对比结果表明,运用所提方法对滚动轴承早期故障进行识别,可以准确有效地诊断出轴承的故障类型,具有一定的实用价值。

基于VMD-SVM的三相异步电机故障诊断方法

针对三相异步电机信号的不稳定性及故障特征提取困难问题,提出一种基于变分模态分解(VMD)与支持向量机(SVM)相融合的电机故障诊断方法。该方法首先将采集的信号通过VMD分解得到IMF分量;其次,计算各个IMF分量的能量,再将其构成特征向量;最后对每种状态随机选取400组输入SVM模型训练,将剩余每种状态100组用于测试,通过预测标签与实际标签的比较来判断电机的故障状态。采用该方法对4种不同的电机状态进行故障诊断,结果表明与完全自适应噪声集合经验模态分解(CEEMDAN)、变分模态分解(VMD)提取各IMF能量特征相比,基于VMD-SVM的三相异步电机故障诊断方法更具优越性。

施用南荻生物炭对水稻养分利用特征的影响

为实现南荻秸秆炭化利用,缓解洞庭湖区因秸秆处置不当造成的环境压力,评估南荻生物炭农用增效潜力,本研究选用南方第四纪红土母质发育的红黄泥和花岗岩母质发育的麻砂泥水稻土,设置6个不同用量的南荻秸秆生物炭处理(质量比0、1%、2%、4%、6%和8%,0~20 cm土层),采用水稻盆栽试验,探究南荻秸秆生物炭不同施用量对两种类型土壤水稻养分利用特征的影响。结果表明,南荻秸秆生物炭不同施用量和土壤类型对水稻各器官及地上部干物质累积、养分吸收均有影响。与不添加生物炭相比,添加生物炭处理下的麻砂泥和红黄泥水稻地上部干质量分别提高了0.6%~18.6%和15.5%~42.4%;添加4%生物炭的麻砂泥水稻地上部氮、磷和钾养分累积量分别提高了8.6%、10.5%和82.5%,红黄泥水稻分别提高了33.8%、100.0%和125.3%;二次回归方程与肥炭耦合模型拟合表明,麻砂泥和红黄泥水稻氮素利用的生物炭适宜添加量分别为2.51%和4.80%,磷素利用的生物炭适宜添加量分别为4.33%和7.03%,钾素利用的生物炭适宜添加量分别为4.67%和4.81%。因此,施用南荻生物炭有利于促进水稻氮磷钾养分累积和生长,生物炭添加量与土壤条件是影响肥炭耦合效应的重要影响因素。

大型综合体育馆开合屋盖使用和维护管理的研究

论文以深圳市体育中心工程项目中的大型开合屋盖为研究对象,深入研究了此类特种装置的使用和维护管理,主要聚焦在调试技术要点、运行管理和定期维护三个关键方面。在调试技术要点方面,论文详细探讨了准备工作、初次运行调试、结构姿态调整、整体联动调试、试验与验收等多个调试阶段的具体步骤。对于运行管理,论文涉及了操作权限、人员技能、开合运行模式设定以及操作规范等内容,强调了首要原则是安全管理。另外,论文强调了定期维护在确保设备稳定运行中的关键作用,将维护划分为一级、二级、三级管理和大修四个阶段,并规范了各级维护阶段的具体内容和周期。论文为大型、特大型开合屋盖或类似工程提供了有益的参考,有助于推动大型体育馆工程领域的快速发展。

CEEMDAN与参数优化多尺度排列熵结合的滚动轴承早期故障诊断

针对滚动轴承的早期故障特征微弱的特点,提出了自适应噪声完备集合经验模态分解(CEEMDAN)与多尺度排列熵(MPE)结合提取故障特征,采用支持向量机(SVM)进行故障状态判别的滚动轴承早期故障诊断方法。利用CEEMDAN将信号分解为若干分量,计算各分量与原信号的相关系数,将大于相关系数阈值的分量重构,对MPE的参数运用PSO算法寻优,计算重构后的信号的MPE值并作为故障特征向量,使用SVM对故障状态进行识别。将该方法运用于XJTU-SY滚动轴承加速寿命试验数据集,并与MPE参数未优化以及未CEEMDAN分解且MPE参数未优化得到的MPE值作为特征向量SVM进行识别的结果进行对比,结果表明本文所提方法的故障识别率分别提高了10.71%和14.28%。

非小细胞肺癌组织的MARCKSL1水平及临床意义

目的探讨非小细胞肺癌(NSCLC)组织的肉豆蔻酰化富含丙氨酸的C激酶底物样蛋白1(MARCKSL1)水平和临床意义。方法采用实时定量PCR(qPCR)检测92对NSCLC组织和癌旁组织的MARCKSL1水平,分层分析组织MARCKSL1水平与临床病理特征和预后关系,结合Cox比例风险模型进行多因素分析。结果NSCLC组织的MARCKSL1水平为2.890±1.042,高于癌旁组织的1.194±0.484(t=14.159,P<0.001)。组织MARCKSL1水平与肿瘤最大径、TNM分期和淋巴结转移有关(P<0.05),且MARCKSL1低水平者的中位总生存期为58.0个月,优于高水平者的41.0个月(P<0.05);组织MARCKSL1水平升高是预后不良的危险因素(HR=2.154,95%CI:1.245~3.754,P=0.016)。结论NSCLC组织中异常高表达的MARCKSL1参与了该肿瘤的恶性进展且与不良预后有关,有望成为NCSLC防治的潜在靶点。

Maintenance of Millimeter-level Geodetic Reference Framework

The high-precision terrestrial reference frame,as the spatial benchmark for geodesy,is an important national infrastructure.However,due to the influence of nonlinear factors related to geophysical phenomena,the overall maintenance accuracy of the ITRF framework is still at the centimeter level.Therefore,accurately characterizing the true trajectories of linear motion,nonlinear motion,and geocentric motion of the reference station is the key to achieve the construction and maintenance technology of a millimeter level terrestrial reference framework.Based on long-term global and regional GNSS observation data,more Chinese geodesy scientists devoted much efforts to the maintenance of millimeter-level geodetic reference framework.The main contributions of this work included the followings:①Dynamic maintenance of millimeter-level terrestrial reference frame;②Research progress on the method of maintenance of regional reference frame based on GNSS;③The progress of CGCS2000 frame maintenance in millimeter level accuracy;④Reprocessing and reanalysis of two-decade GNSS observation in continental China;⑤Research on current GNSS velocity field model and deformation in Chinese mainland;⑥The preliminary realization and evaluation of CTRF2020.

脱硫石膏脱水困难的原因分析及措施

石灰-石膏湿法烟气脱硫工艺广泛应用于火力发电、化工等行业。石灰浆液的成分会影响脱硫效率,石膏脱水的难易程度会影响系统运行压力,含水率会影响石膏品质,并会增加生产成本和储存难度。石膏滤液循环使用一段时间后,会出现石膏脱水困难的情况,为此本文研究了碱性环境对石膏晶体粒径的影响,分析了石膏脱水困难的原因,并提出了应对措施。

不同干燥方式对封鳊鱼品质的影响

为探明不同干燥方式对封鳊鱼品质及鱼肉理化性质的影响,试验采用自然、冷风、冷冻、冷风—热风联合和热泵5种干燥方式对封鳊鱼进行干燥,研究不同干燥方式对鳊鱼质量损失、干燥速率、硫代巴比妥酸值、挥发性盐基总氮、水分活度、复水率、质构特性和微观结构的影响。试验结果表明,自然干燥的干燥速率低、鱼肉复水率差、氧化最严重、腐败程度较高,但弹性和咀嚼性较好;冷冻干燥的干燥速率最快,鱼肉复水率最高,氧化和腐败程度最低,但弹性和咀嚼性差;冷风干燥的干燥速率低,但鱼肉复水率较好,仅低于冷冻干燥,氧化和腐败程度也仅高于冷冻干燥,且弹性和咀嚼性最好;热泵干燥的干燥速率较高,但鱼肉复水率低、氧化和腐败程度均较高、质构特性较差;联合干燥的干燥速率较快,但鱼肉复水率最低、腐败最严重、质构特性差。

一种富含硫酸软骨素含片的加工工艺

目的:以富含海洋硫酸软骨素的鲨鱼软骨粉为主要原料,研发一种具有改善关节效果的含片。方法:以感官综合评价为考察指标,通过单因素试验和正交试验设计分析,利用模糊综合评价方法优化工艺配方。结果:含片最佳配方为鲨鱼软骨粉添加量50.0%,乳粉添加量25.0%,青柠檬果粉添加量8.0%,预胶化淀粉添加量5.5%,硬脂酸镁添加量0.3%,阿斯巴甜添加量0.8%。结论:经长期试验和加速试验,产品均符合相关标准,可为海洋功能性食品的开发提供参考。

丁香油对蟹黄鲜虾酱贮藏品质的影响

将丁香油添加到蟹黄鲜虾酱中,25℃恒温贮藏180d,通过对蟹黄鲜虾酱贮藏过程中丙二醛含量、总巯基含量、脂肪酸组成及含量、呈味物质含量进行定期检测,并结合滋味物质的味道强度值和味道当量在贮藏过程中的变化,探索丁香油对蟹黄鲜虾酱贮藏过程品质的影响。结果显示,丁香油能抑制丙二醛的生成、总巯基的降低和不饱和脂肪酸的分解,添加丁香油的蟹黄鲜虾酱呈味核苷酸、鲜味氨基酸、甜味氨基酸、游离氨基酸含量和味精当量值显著高于不添加丁香油的蟹黄鲜虾酱。研究表明,在贮藏过程中,丁香油对蟹黄鲜虾酱不仅具有抗脂肪和蛋白质氧化的作用,还能够提高其贮藏稳定性和风味。