美对华半导体管制的趋势、实施要点与中国因应

针对不断升级的中美半导体领域争端,本文梳理了美国对华半导体管制的趋势与要点。从特朗普政府到拜登政府,美对华半导体管制呈现出由“有限出口”向“全面出口管制”、由“5G”延伸至“AI”、由“大棒”扩展为“胡萝卜加大棒”、从“单边约束”扩展到“多边合围”的趋势。从管制要点来看,拜登政府在半导体产业链的所有关键环节都设计了阻碍中国技术进步的方案,不但限制高算力芯片成品对华出口,而且限制产业链上游的芯片制造设备、零部件、芯片设计软件出口以及产业链下游的算力租赁服务。针对美政府全方位围堵,本文提出对外强化与非热点半导体国家的联系、重视非传统技术路线半导体开发、借鉴比利时微电子研究中心运作模式发展共性技术机构等产业突围思路。

农职校与山区农村共建党支部服务乡村振兴的优势和途径

文章深入调研了当前山区农村基层党建工作的现状,探究了山区农村党建带动产业发展实现乡村振兴的痛点堵点,提出涉农高职院校与山区农村共建党支部,以便强化山区农村党员理论水平、提升基层党建活力、构建双赢机制的重大意义,指出了组织共建、干部共管、人才共育、资源共享等共建党支部服务乡村振兴战略的途径。

工艺、技术与建筑的整合——电子高科技芯片厂房设计实践

简要介绍芯片生产的工艺、流程及关键技术。从总体布局、建筑设计两个层面阐述国家存储器基地项目(一期)的设计思考,在满足工艺需求的基础上,建筑师可以通过建筑立面、厂房外部色彩的处理体现工业建筑之美。深入挖掘项目分期实施策略、建筑消防设计特征及空间管理概念。

铁浴条件下电炉粉尘球团的熔融与分离行为

为了提高对含锌电弧炉粉尘(EAFD)的利用效率,实验研究EAFD球团在铁浴条件下的还原熔化行为。定义铁液滴球形度作为判断其凝聚的标准,然后探讨铁液滴直径和球形度之间随时间变化的关系。根据实验最终建立EAFD颗粒的熔化和分离行为。结果表明,在铁浴条件下,EAFD球团的Zn去除率在5.0 min时达到99%以上,但在15.0 min时金属渣分离还没有完成。由于成分的波动,在EAFD球团中形成几个区域的液态渣,然后液态渣不断增加,直到球团完全熔化。球形度>65%、直径>500μm的Fe液滴的数量随着时间的推移而减少,大直径的Fe液滴先完成分离。渣铁分离过程如下:在布朗运动下Fe液滴在渣中形成,之后Fe液滴直径在马兰戈尼效应下增加,Fe液滴在渣中下降速度符合斯托克斯定律。

LP油田沉降罐过渡带原油破乳脱水实验研究

LP油田沉降罐过渡带原油中含有起乳化作用的胶态FeS等成分,导致原油脱水困难,不能满足原油进后续电脱水器的要求;分析了过渡带原油物性、原油组分及采出水组成,对FeS脱除剂及破乳剂的筛选进行优化实验,重点研究了FeS脱除剂与破乳剂联合破乳效果及适应性。结果表明,筛选出的FeS脱除剂BLJ-01对FeS有很好的溶解效果,体积分数3%的FeS脱除剂BLJ-01和质量浓度800 mg/L的破乳剂X-75联合使用,55℃下可有效去除沉降罐过渡带原油中FeS,沉降罐过渡带原油脱水率达85.78%;BLJ-01与X-75配合使用适应性较强,对含水率超过40%的P2联合站沉降罐过渡带原油脱水率均可达80%以上,且在弱酸或弱碱性条件下都可以表现出优良的破乳效果,也适用于SJ站沉降罐过渡带原油的破乳脱水,并能显著降低破乳剂使用量。

大坝安全监测数字孪生系统应用研究

针对传统大坝安全监测系统在海量数据管理、风险识别灵敏度及预警预报响应时效方面存在的不足,采用基于Revit的BIM技术与Three.js可视化技术,构造与原型高度相似的数字模型,通过有限元法迭代进行材料性能参数反演,进而分析得到大坝各部位运行性态;利用MySQL关系数据库技术、NEO4J图数据库技术、智能算法及微服务技术进行数据管理,构建包含完整监测信息的大坝数字孪生安全监测系统。通过嵌入的概率图模型进行大坝安全风险评估,实现大坝的在线监测、实时参数反演和安全风险评估,并对未来工况进行安全性态预测和预警。工程应用实践表明,系统在风险识别和预测预警的实时、高效、准确性等各方面都得到极大改进,显著提升了大坝安全管理效率与抵御风险的能力。可为同类型工程的安全监测系统提供借鉴。

碳纤维增强聚合物复合材料水导激光切割损伤机理研究

碳纤维增强聚合物(CFRP)复合材料在水导激光加工后,切缝表面和横截面存在热损伤,这些损伤是影响材料力学性能、降低材料服役性能的重要因素。针对该问题,采用试验方法分析了加工参数对沟槽几何形貌和表面形貌的影响规律,研究了沟槽表面和横截面的热损伤形成机理。研究结果表明:高激光功率、低脉冲频率和低切割速度可有效增大沟槽深度;激光与材料的相互作用和水射流的冲刷作用是形成沟槽表面热损伤的主要原因。在2 mm厚CFRP切割试验中发现:横截面热影响区宽度与纤维排布方向有关,0°碳纤维热影响区宽度最大,45°和135°碳纤维热影响区宽度次之且宽度相近,90°碳纤维热影响宽度最小;另外,提高水射流速度有利于抑制热影响区的扩展,水射流速度由80 m/s提高至120 m/s,最大热影响宽度缩小35.7%。

Au NPs/Cu-TCPP材料的构筑及其催化薄荷醇氧化的研究

二维纳米片具有大的比表面积和高孔隙率的特征,这使得其可以承载更多的活性中心,从而提高该材料的催化性能。如Cu-TCPP纳米片,拥有大的比表面积,可用于负载Pd NPs、Pt NPs以及Au NPs,以获得X NPs/Cu-TCPP纳米片(X=Pd NPs、Pt NPs和Au NPs)。本研究首先通过水热法,以三水合硝酸铜(Cu(NO_(3))_(2)·3H_(2)O)为金属盐,4-羧基卟啉(TCPP)为有机配体,N,N-二甲基甲酰胺(DMF)和CH_(3)CH_(2)OH(体积比3∶1)的混合溶液作为溶剂,合成Cu-TCPP纳米片。随后,采用还原法将Au NPs负载到Cu-TCPP纳米片上,形成Au NPs/Cu-TCPP纳米片,用于催化薄荷醇进行选择性氧化反应。在反应中,以叔丁基过氧化氢(TBHP)为氧化剂,乙腈(Me CN)为溶剂,氨基酸咪唑离子液体([C_(4)mim]Cys)为助催化剂,Au NPs/Cu-TCPP催化薄荷醇进行选择性氧化,生成薄荷酮。在50℃下反应18 h,薄荷醇的转化率和薄荷酮的选择性和产率都达到最高,分别为70.2%,99.9%和69.5%,该方法不仅将薄荷醇转化为高选择性的薄荷酮,而且操作简便,绿色环保,符合当前绿色化工发展的要求。

工业机器人装配中基于相机位姿估计算法的单目视觉定位研究

为了提升工业机器人在装配作业中的效率和精准度,结合软指派算法进行研究,构建基于相机位姿估计算法的单目标视觉定位系统,并对其进行仿真验证。实验结果显示,在参数对成功率的影响实验中实验成功率最低为92.5%,在图像噪声对成功率的影响实验中成功率最高达到了97.5%,位置估计误差最大值不超过4 mm,旋转误差在伪特征点的数量为最大时得到了最大值7°。

基于SBO-LSTM的大坝变形预测模型

变形是大坝安全性态的综合反映,建立其与环境量的可靠关系模型对保障大坝长效服役具有重要意义。为提高大坝变形预测的精度和泛化能力,并解决长短期记忆神经网络(LSTM)参数选取随机性大、选取困难的问题,提出了一种利用缎蓝园丁鸟优化算法(SBO)来优化长短期记忆神经网络的混凝土坝变形预测模型(SBO-LSTM)。该方法首先通过高斯滤波和Symlet小波滤值两种方法对选定的监测数据进行统一的清洗、归一化、去噪等预处理;其次,借助SBO算法对长短期记忆神经网络模型的超参数进行寻优;最后对混凝土坝变形进行高精度预测并通过三种不同评价指标(MAE,RMSE,MAPE)对预测结果进行评价。以某混凝土坝为例并与传统优化算法对比分析,结果表明通过SBO算法优化后LSTM神经网络具有更高的预测精度和稳定性,综上,该预测模型为大坝变形监测数据分析与预测提供了一种新的可行方法。

Diagnostic value associated with the combination of saliva pepsin and microorganisms in functional heartburn and gastroesophageal reflux disease

Heartburn is a common symptom shared by both gastroesophageal reflux disease(GERD)and functional heartburn(FHB),which can make it challenging to differentiate between the two conditions.However,examining oral manifestations of GERD can be a cost-effective and readily available method to aid in this differentiation process.It may serve as a valuable tool in distinguishing GERD from FHB.

Systematic Elastostatic Stiffness Model of Over-Constrained Parallel Manipulators Without Additional Constraint Equations

The establishment of an elastostatic stiffness model for over constrained parallel manipulators(PMs),particularly those with over constrained subclosed loops,poses a challenge while ensuring numerical stability.This study addresses this issue by proposing a systematic elastostatic stiffness model based on matrix structural analysis(MSA)and independent displacement coordinates(IDCs)extraction techniques.To begin,the closed-loop PM is transformed into an open-loop PM by eliminating constraints.A subassembly element is then introduced,which considers the flexibility of both rods and joints.This approach helps circumvent the numerical instability typically encountered with traditional constraint equations.The IDCs and analytical constraint equations of nodes constrained by various joints are summarized in the appendix,utilizing multipoint constraint theory and singularity analysis,all unified within a single coordinate frame.Subsequently,the open-loop mechanism is efficiently closed by referencing the constraint equations presented in the appendix,alongside its elastostatic model.The proposed method proves to be both modeling and computationally efficient due to the comprehensive summary of the constraint equations in the Appendix,eliminating the need for additional equations.An example utilizing an over constrained subclosed loops demonstrate the application of the proposed method.In conclusion,the model proposed in this study enriches the theory of elastostatic stiffness modeling of PMs and provides an effective solution for stiffness modeling challenges they present.

Silencing of early auxin responsive genes MdGH3-2/12 reduces the resistance to Fusarium solani in apple

Apple replant disease(ARD)has led to severe yield and quality reduction in the apple industry.Fusarium solani(F.solani)has been identified as one of the main microbial pathogens responsible for ARD.Auxin(indole-3-acetic acid,IAA),an endogenous hormone in plants,is involved in almost all plant growth and development processes and plays a role in plant immunity against pathogens.Gretchen Hagen3(GH3)is one of the early/primary auxin response genes.The aim of this study was to evaluate the function of MdGH3-2 and MdGH3-12 in the defense response of F.solani by treating MdGH3-2/12 RNAi plants with F.solani.The results show that under F.solani infection,RNAi of MdGH3-2/12 inhibited plant biomass accumulation and exacerbated root damage.After inoculation with F.solani,MdGH3-2/12 RNAi inhibited the biosynthesis of acid-amido synthetase.This led to the inhibition of free IAA combining with amino acids,resulting in excessive free IAA accumulation.This excessive free IAA altered plant tissue structure,accelerated fungal hyphal invasion,reduced the activity of antioxidant enzymes(SOD,POD and CAT),increased the reactive oxygen species(ROS)level,and reduced total chlorophyll content and photosynthetic ability,while regulating the expression of PR-related genes including PR1,PR4,PR5 and PR8.It also changed the contents of plant hormones and amino acids,and ultimately reduced the resistance to F.solani.In conclusion,these results demonstrate that MdGH3-2 and MdGH3-12 play an important role in apple tolerance to F.solani and ARD.

Multifunctional catalytic sites regulation of atomic-scale iridium on orthorhombic-CoSe_(2)for high efficiency dual-functional alkaline hydrogen evolution and organic degradation

The earth-abundant and high-performance catalysts are crucial for commercial implementation of hydrogen evolution reaction(HER).Herein,a multifunctional site strategy to construct excellent HER catalysts by incorporating iridium(Ir)ions on the atomic scale into orthorhombic-CoSe2(Ir-CoSe_(2))was reported.Outstanding hydrogen evolution activity in alkaline media such as a low overpotential of 48.7 mV at a current density of 10 mA cm^(-2)and better performance than commercial Pt/C catalysts at high current densities were found in the Ir-CoSe_(2) samples.In the experiments and theoretical calculations,it was revealed that Ir enabled CoSe_(2)to form multifunctional sites to synergistically catalyze alkaline HER by promoting the adsorption and dissociation of H_(2)O(Ir sites)and optimizing the binding energy for H^(*)on Co sites.It was noticeable that the electrolytic system comprising the Ir-CoSe_(2)electrode not only produced hydrogen efficiently via HER,but also degraded organic pollutants(Methylene blue).The cell voltage of the dual-function electrolytic system was 1.58 V at the benchmark current density of 50 mA cm^(-2),which was significantly lower than the conventional water splitting voltage.It was indicated that this method was a novel strategy for designing advanced HER electrocatalysts by constructing multifunctional catalytic sites for hydrogen production and organic degradation.

Heat exposure and hospitalizations for chronic kidney disease in China: a nationwide time series study in 261 major Chinese cities

Background:Climate change profoundly shapes the population health at the global scale.However,there was still insufficient and inconsistent evidence for the association between heat exposure and chronic kidney disease(CKD).Methods:In the present study,we studied the association of heat exposure with hospitalizations for cause-specific CKD using a national inpatient database in China during the study period of hot season from 2015 to 2018.Standard time-series regression models and random-effects Meta-analysis were developed to estimate the city-specific and national averaged associations at a 7 lag-day span,respectively.Results:A total of 768,129 hospitalizations for CKD was recorded during the study period.The results showed that higher temperature was associated with elevated risk of hospitalizations for CKD,especially in sub-tropical cities.With a 1℃ increase in daily mean temperature,the cumulative relative risks(RR)over lag 0-7 d were 1.008[95% confidence interval(CI)1.003-1.012]for nationwide.The attributable fraction of CKD hospitalizations due to high temperatures was 5.50%.Stronger associations were observed among younger patients and those with obstructive nephropathy.Our study also found that exposure to heatwaves was associated with added risk of hospitalizations for CKD compared to non-heatwave days(RR=1.116,95%CI 1.069-1.166)above the effect of daily mean temperature.Conclusions:Short-term heat exposure may increase the risk of hospitalization for CKD.Our findings provide insights into the health effects of climate change and suggest the necessity of guided protection strategies against the adverse effects of high temperatures.

Research progress on catalysts for organic sulfur hydrolysis: Review of activity and stability

The removal of organic sulfur through catalytic hydrolysis is a significant area of research in the field of desulfurization.This review provides an overview of recent advancements in catalytic hydrolysis technology of organic sulfur,including the activity,stability,and atmosphere effects of hydrolysis catalysts.The emphasis is on strategies for enhancing hydrolysis activity and anti-oxygen poisoning property of catalysts.Surface modification,metal doping and nitrogen doping have been found to improve the activity of catalysts.Alkaline components modification is the most commonly used method,the formation of oxygen vacancies through metal doping and creation of nitrogen basic sites through nitrogen doping also contribute to the hydrolysis of organic sulfur.The strategies for anti-oxygen poisoning are discussed in a systematic manner.The structural regulation of catalysts is beneficial for the desorption and diffusion of hydrogen sulfide(H_(2)S),thereby effectively inhibiting its oxidation.Nitrogen doping and the addition of electronic promoters such as transition metals can protect active sites and decrease the number of active oxygen species.These methods have been proven to enhance the anti-poisoning performance of catalysts.Additionally,this article summarizes how different atmospheres affect the activity of hydrolysis catalysts.The objective of this review is to pave the way for the development of efficient,stable and widely used catalysts for organic sulfur hydrolysis.

Defect engineering on BiFeO_(3) through Na and V codoping for aqueous Na-ion capacitors

Sodium with low cost and high abundance is considered as a substitute element of lithium for batteries and supercapacitors,which need the appropriate host materials to accommodate the relatively large Na^(+) ions.Compared to Li^(+) storage,Na^(+) storage makes higher demands on the structural optimization of perovskite bismuth ferrite(BiFeO_(3)).We propose a novel strategy of defect engineering on BiFeO_(3) through Na and V codoping for high-efficiency Na^(+) storage,to reveal the roles of oxygen vacancies and V ions played in the enhanced electrochemical energy storage performances of Na-ion capacitors.The formation of the oxygen vacancies in the Na and V codoped BiFeO_(3)(denoted as NV-BFO),is promoted by Na doping and suppressed by V doping,which can be demonstrated by XPS and EPR spectra.By the first-principles calculations,the oxygen vacancies and V ions in NV-BFO are confirmed to substantially lower the Na^(+)migration energy barriers through the space and electric field effects,to effectively promote the Na^(+) transport in the crystals.Electrochemical kinetic analysis of the NV-BFO//NV-BFO capacitors indicates the dominant capacitive-controlled capacity,which depends on fast Na^(+) deintercalation-intercalation process in the NV-BFO electrode.The NV-BFO//NV-BFO capacitors open up a new avenue for developing highperformance Na-ion capacitors.

NaF assisted preparation and the improved corrosion resistance of high content ZnO doped plasma electrolytic oxidation coating on AZ31B alloy

In the present research,the NaF assisted plasma electrolytic oxidation(PEO)is designed to fabricate the high-content ZnO nanoparti-cles doped coating on AZ31B alloy.The microstructure,phase constituents and corrosion behavior of the PEO coatings are investigated systematically.The results reveal that the introduction of NaF promotes the formation of MgF2 nanophases in the passivation layer on Mg alloy,decreasing the breakdown voltage and discharge voltage.As a result,the continuous arcing caused by high discharge voltage is alleviated.With the increasing of NaF content,the Zn content in the PEO coating is enhanced and the pore size in the coating is decreased correspondingly.Due to the high-content ZnO doping,the PEO coating protected AZ31B alloy demonstrates the better corrosion resistance.Compared with the bare AZ31B alloy,the high-content ZnO doped PEO coated sample shows an increased corrosion potential from-1.465 V to-1.008 V,a decreased corrosion current density from 3.043×10^(-5) A·cm^(-2) to 3.960×10^(-8) A·cm^(-2) and an increased charge transfer resistance from 1.213×10^(2) ohm·cm^(2) to 2.598×10^(5) ohm·cm^(2).Besides,the high-content ZnO doped PEO coated sample also has the excellent corrosion resistance in salt solution,exhibiting no obvious corrosion after more than 2000 h neutral salt spraying and 28 days’immersion testing.The improved corrosion resistance can be ascribed to the relative uniform distribution of ZnO in PEO coating which can transform to Zn(OH)2 and form a continuous protective layer along the corrosion interface.

Combinatorial reasoning-based abnormal sensor recognition method for subsea production control system

The subsea production system is a vital equipment for offshore oil and gas production.The control system is one of the most important parts of it.Collecting and processing the signals of subsea sensors is the only way to judge whether the subsea production control system is normal.However,subsea sensors degrade rapidly due to harsh working environments and long service time.This leads to frequent false alarm incidents.A combinatorial reasoning-based abnormal sensor recognition method for subsea production control system is proposed.A combinatorial algorithm is proposed to group sensors.The long short-term memory network(LSTM)is used to establish a single inference model.A counting-based judging method is proposed to identify abnormal sensors.Field data from an offshore platform in the South China Sea is used to demonstrate the effect of the proposed method.The results show that the proposed method can identify the abnormal sensors effectively.

Synthesis of NaY zeolite from a submolten depolymerized perlite:Alkalinity effect and crystallization kinetics

NaY zeolites are synthesized using submolten salt depolymerized natural perlite mineral as the main silica and alumina sources in a 0.94 L stirred crystallizer.Effects of alkalinity ranging from 0.38 to 0.55(n(Na_(2)O)/n(SiO_(2)))on the relative crystallinity,textural properties and crystallization kinetics were investigated.The results show that alkalinity exerts a nonmonotonic influence on the relative crystallinity and textural properties,which exhibit a maximum at the alkalinity of 0.43.The nucleation kinetics are studied by fitting the experimental data of relative crystallinity with the Gualtieri model.It is shown that the nucleation rate constant increases with increasing alkalinity,while the duration period of nucleation decreases with increasing alkalinity.For n(Na_(2)O)/n(SiO_(2))ratios ranging from 0.38 to 0.55,the as-synthesized NaY zeolites exhibit narrower crystal size distributions with the increase in alkalinity.The growth rates determined from the variations of average crystal size with time are 51.09,157.50,46.17 and 24.75 nm·h^(-1),respectively.It is found that the larger average crystal sizes at the alkalinity of 0.38 and 0.43 are attributed to the dominant role of crystal growth over nucleation.Furthermore,the combined action of prominent crystal growth and the longer duration periods of nucleation at the alkalinity of 0.38 and 0.43 results in broader crystal size distributions.The findings demonstrate that control of the properties of NaY zeolite and the crystallization kinetics can be achieved by conducting the crystallization process in an appropriate range of alkalinity of the reaction mixture.