不同应变率加载下硅的高压相变行为

高压相变是凝聚态物理、地球与行星科学、材料科学等领域关注的核心问题之一,而加载应变率是相变动力学过程的重要影响因素。由于动态加载下物质相结构原位诊断技术的不足以及宽广加载应变率下物质高压相变系统实验研究的缺失,难以开展基于原子尺度物理机制的相变动力学过程建模和数值模拟研究。由于硅的高压相极其丰富,且拥有大量亚稳相,动力学因素在其高压相变过程中发挥着至关重要的作用,因此,硅是研究高压相变动力学的理想材料,对普适相变动力学过程的理论建模具有重要意义。以硅为例,介绍其在准静态、中等应变率和高应变率加载下的相变行为,探讨加载应变率对其高压相变行为的影响。

基于NOMA的共生反向散射通信的性能分析

非正交多址接入和环境反向散射通信是提高无线通信系统频谱效率的关键技术.针对能量受限问题,提出了一种基于瑞利衰落信道的下行非正交多址接入多路传输的共生反向散射通信系统.该系统由1个源节点S、1个反向散射设备BD和1个目的节点D组成.考虑到实际的非线性能量收集模型,在满足反射设备的能量因果约束的情况下,采用了一种最优动态反射系数以最大化反向散射信号的功率,推导了该系统中断概率的解析表达式,通过仿真验证了理论推导的正确性.仿真结果表明,反射设备电路的自身损耗对系统中断性能有重要影响.此外,通过仿真对比分析了基于非正交多址的共生反向散射通信系统和基于正交多址的共生反向散射通信系统性能,结果表明基于非正交多址的共生反向散射通信系统具有更好的中断性能.

粤港澳大湾区科技园地域性设计研究综述

文章综述了大湾区科技园地域性设计的理论研究进展;基于科技园地域性设计实践分类标准,对案例的类型及特点进行梳理;提出研究展望,以期为我国高质量发展背景下科技园的地域性设计提供参考。

内观认知疗法对医学生焦虑水平、自我效能感和应对方式的干预及机制

目的:探究内观认知疗法对医学生焦虑水平、自我效能感和应对方式的影响,并考察医学生内观认知疗法干预、自我效能感、应对方式和焦虑水平间的关系,以期为医学生心理健康教育工作和NCT疗法的作用机制研究提供理论支持。方法:采用随机数字表法将70名符合筛选标准的研究对象随机分配到内观认知疗法组和心理健康教育组,每组35人。内观认知疗法组接受为期7天的内观认知疗法干预,心理健康教育组接受相同时间的常规心理健康教育,最终共68人完成试验(内观认知疗法组34人,心理健康教育组34人)。干预前后使用SAS、GSES、SCSQ量表对两组研究对象进行测评。结果:①干预前,内观认知疗法组与心理健康教育组在焦虑,自我效能感,积极和消极应对方式得分上均不存在显著差异。②干预后,内观认知疗法组焦虑得分显著降低(t=5.835;P<0.01),自我效能感和积极应对方式得分均显著升高(t=2.289,4.668;P<0.05),消极应对方式得分不存在显著差异,干预前后心理健康教育组在上述所有量表得分中均不存在显著差异。③干预后,内观认知疗法组自我效能感和积极应对方式得分显著高于心理健康教育组(t=2.653,3.122;P<0.01),焦虑得分显著低于心理健康组(t=2.562;P<0.05)。④中介效应检验方面,内观认知疗法既可以直接影响医学生焦虑水平(β=-0.293,95%CI=-3.755~0.008),也可以通过自我效能感的中介作用(β=-0.307,95%CI=-0.612~-0.028)、积极应对方式的中介作用(β=0.140,95%CI=-0.293~-0.004)及自我效能感和积极应对方式的链式中介作用(β=0.222,95%CI=-0.553~-0.022)间接影响医学生焦虑水平。结论:内观认知疗法是一种能够有效降低医学生焦虑水平的干预手段,既能直接缓解焦虑,也能通过提高医学生自我效能感水平,改善积极应对方式间接降低医学生焦虑水平。

基于改进YOLOv8的轻量化小麦病害检测方法

为提高小麦病害检测精度,实现将模型方便快速部署到移动端,该研究提出了一种基于改进YOLOv8的轻量化小麦病害检测方法。首先,使用PP-LCNet模型替换YOLOv8网络结构的骨干网络,并在骨干网络层引入深度可分离卷积(depthwise separable convolution, DepthSepConv)结构,减少模型参数量,提升模型检测性能;其次,在颈部网络部分添加全局注意力机制(global attention mechanism, GAM)模块,强化特征中语义信息和位置信息,提高模型特征融合能力;然后,引入轻量级通用上采样内容感知重组(content-aware reassembly of features,CARAFE)模块,提高模型对重要特征的提取能力;最后,使用Wise-IoU(weighted interpolation of sequential evidence for intersection over union)边界损失函数代替原损失函数,提升网络边界框回归性能和对小目标病害的检测效果。试验结果表明,对于大田环境下所采集的小麦病害数据集,改进后模型的参数量及模型大小相比原YOLOv8n基线模型分别降低了12.5%和11.3%,同时精确度(precision)及平均精度均值(mean average precision,m AP)相较于原模型分别提高了4.5和1.9个百分点,优于其他对比目标检测算法,可为小麦病害检测无人机等移动端检测装备的部署和应用提供参考。

BiOBr/ATP的制备及光催化降解四环素性能研究

通过湿式机械化学合成法一步制备了BiOBr/ATP复合光催化剂,利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、红外光谱(FT-IR)和X射线能谱(XPS)等对所制备催化剂的微观结构和形貌进行表征,通过在可见光照射下光催化降解四环素评价催化剂的活性,并考察了其降解四环素类抗生素的性能和机理.结果表明,凹凸棒土棒晶(ATP)与溴氧铋(BiOBr)纳米片之间形成了插层结构,且在ATP质量分数为5%时,复合材料的光催化效果最佳,四环素降解率达到88.23%.通过自由基抑制实验推测主要作用是(·O^(2−)),并提出了可能的四环素降解机制.根据活性物种捕获实验,·O^(2−)和·OH是主要活性物种,h^(+)和e^(−)是次要活性物种.瞬态光电流测试表明,BiOBr/ATP复合光催化剂的光电流增强是BiOBr的1.24倍.

肝癌TACE术后复发危险因素的Meta分析

目的 系统评价肝癌经动脉化疗栓塞术(transcatheter arterial chemoembolization, TACE)后影响复发的危险因素,为预防TACE术后复发提供科学依据。方法 检索PubMed、EmBase、Cochrane Library、Web of Science、中国知网、万方数据库、维普、中国生物医学文献数据库自建库至2023年2月1日发表的有关肝癌TACE术后复发危险因素的文献报道。由2名研究者根据纳入和排除标准进行文献筛选、数据提取和质量评价。使用软件Rev Man 5.3对纳入文献进行Meta分析和发表偏倚评估。结果 通过筛选最终共纳入9篇高质量队列研究进行Meta分析。分析结果显示差异有统计学意义的危险因素包括甲胎蛋白(OR=3.05,95%CI:1.11~8.38,P=0.03)、白蛋白(OR=5.79,95%CI:2.46~13.62,P<0.0001)、肿瘤分化程度(OR=2.64,95%CI:1.00~6.92,P=0.05)、肿瘤数量(OR=3.76,95%CI:1.71~8.27,P=0.001)、肿瘤ADC值(OR=0.01,95%CI:0.00~0.09,P<0.0001)。结论 肿瘤直径、甲胎蛋白、白蛋白、肿瘤分化程度、肿瘤数量和肿瘤ADC值是TACE术后复发的危险因素。

“X的X,Y的Y”构式的形、动二分格局及其特征探析

“X的X,Y的Y”是一种常见的构式,其构式义是对人或事物状态的多种描绘,以及对动作或事件的分项列举。通过分析“X的X,Y的Y”构式的构成成分,发现“X的X,Y的Y”构式在形式、功能上呈现出明显的形、动二分格局,并具有以下特征:形容词、动词以外的词类不能进入该构式;形容词类“X的X,Y的Y”构式总表示消极义;“X的X”或“Y的Y”不能单说。本研究集中描写“X的X,Y的Y”构式在形容词类和动词类上的差异,并运用语言使用中的语用推理、认知框式激活效应以及信息结构的足量原则等对上述语言现象作出一定的解释,以期为现代汉语常见构式的研究提供借鉴,同时加深对现代汉语动词词类、形容词词类范畴的认识。

粘合式与组合式偏正结构的句法语义研究

学界以往通常将体词性偏正结构划分为粘合式与组合式,认为二者主要是组合方式不同。实际上,粘合式与组合式在本质上反映了定语与中心语不同的句法、语义关系。根据各自的语义角色,粘合式与组合式的定语成分进入DP短语的不同位置。粘合式定语生成在中心语的补足语位置,表达最本质的属性。组合式可以细分为三类,其中,“的”字结构作修饰语时,生成在中心语的附加语位置;指示词(+量词)、数词+量词、量化词,生成在限定词位置;领属语则可以出现在NP或DP的标示语位置上。这一句法设定与定语的线性语序排列要求一一对应。

政治嵌入和政治吸纳——沙特构建政治稳定的方式及其影响

政治嵌入机制和政治吸纳机制是沙特构建政治稳定的重要方式。沙特构建面向宗教集团和部落的政治嵌入机制,将国家权力嵌入主要政治势力。同时,沙特建立面向宗教集团、精英和平民的政治吸纳机制,将其纳入国家主流政治生活。政治嵌入机制和政治吸纳机制实现了权力的集中和统一,强化了政治调控能力,部分地满足了国民的政治参与诉求,重构了维系政治稳定的力量格局,最终促使沙特政治稳定得以长期维持。

话语标记“真的”的互动功能与影响因素

话语标记“真的”在序列结构的分布主要包括三种类型:1)评价序列;2)回应序列;3)信息告知序列。其互动功能主要涉及三个方面:1)强化认识立场;2)促进立场趋同;3)凸显互动话题。文章还探讨了交际双方认识状态对“真的”互动功能的影响。

The Philosophy of He(和):Examined from the Perspectives of Technology and Culture

Pre-modern Chinese crafts,such as iron smelting,cookery,medicine,and the production of vehicles,bows,and arrows indicate the traditional Chinese view of technology as being organic,holistic,and comprehensive.This view of technology is guided by the concept of he(和)and employs the means and methods of he,thus achieving the purport of he.In Chinese,the character he(和)possesses positive connotations.It originated from the meaning of"to season;to add flavoring to"(调和)and that of flavors being"perfectly harmonious"(和美).From this sensory experience,he gradually extended to the abstract levels of materiality,humanity,sociality,"order"(wei位),and "power,situation,force"(shi势).Finally,he was elevated to the supreme level of"qi of great harmony"(taihe zhi qi太和之气),which is comparable to the concept of dao(道).The philosophy of he has exerted wide impact on such areas as technology,art,national character,cultural psychology,and behavior patterns,and has become an integral part of China's inherent culture.The paradoxes and deviations of he hold their own profound philosophical implications that merit further exploration.As humanity confronts significant challenges,such as how we can coexist with others,with technology,and with nature,the ancient Eastern wisdom embodied in he continues to possess practical characteristics and value.

An Improved Framework of Massive Superpoly Recovery in Cube Attacks Against NFSR-Based Stream Ciphers

A critical problem in the cube attack is how to recover superpolies efficiently.As the targeting number of rounds of an iterative stream cipher increases,the scale of its superpolies becomes larger and larger.Recently,to recover massive superpolies,the nested monomial prediction technique,the algorithm based on the divide-and-conquer strategy,and stretching cube attacks were proposed,which have been used to recover a superpoly with over ten million monomials for the NFSR-based stream ciphers such as Trivium and Grain-128AEAD.Nevertheless,when these methods are used to recover superpolies,many invalid calculations are performed,which makes recovering superpolies more difficult.This study finds an interesting observation that can be used to improve the above methods.Based on the observation,a new method is proposed to avoid a part of invalid calculations during the process of recovering superpolies.Then,the new method is applied to the nested monomial prediction technique and an improved superpoly recovery framework is presented.To verify the effectiveness of the proposed scheme,the improved framework is applied to 844-and 846-round Trivium and the exact ANFs of the superpolies is obtained with over one hundred million monomials,showing the improved superpoly recovery technique is powerful.Besides,extensive experiments on other scaled-down variants of NFSR-based stream ciphers show that the proposed scheme indeed could be more efficient on the superpoly recovery against NFSR-based stream ciphers.

Some Remarks on Cocks'Identity-Based Encryption Scheme

The theory of quadratic residues plays an important role in cryptography.In 2001,Cocks developed an identity-based encryption(IBE)scheme based on quadratic residues,resolving Shamir’s 17-year-old open problem.However,a notable drawback of Cocks’scheme is the significant expansion of the ciphertext,and some of its limitations have been addressed in subsequent research.Recently,Cotan and Teşeleanu highlighted that previous studies on Cocks’scheme relied on a trial-and-error method based on Jacobi symbols to generate the necessary parameters for the encryption process.They enhanced the encryption speed of Cocks’scheme by eliminating this trialand-error method.Based on security analysis,this study concludes that the security of Cotan-Teşeleanu’s proposal cannot be directly derived from the security of the original Cocks’scheme.Furthermore,by adopting the Cotan-Teşeleanu method and introducing an additional variable as a public element,this study develops a similar enhancement scheme that not only accelerates the encryption speed but also provides security equivalent to the original Cocks’scheme.

C-H bond activation of propane on Ga_(2)O_(2)^(2+) in Ga/H-ZSM-5 and its mechanistic implications

Propane dehydrogenation(PDH)on Ga/H-ZSM-5 catalysts is a promising reaction for propylene production,while the detail mechanism remains debatable.Ga_(2)O_(2)^(2+) stabilized by framework Al pairs have been identified as the most active species in Ga/H-ZSM-5 for PDH in our recent work.Here we demonstrate a strong correlation between the PDH activity and a fraction of Ga_(2)O_(2)^(2+) species corresponding to the infrared GaH band of higher wavenumber(GaHHW)in reduced Ga/H-ZSM-5,instead of the overall Ga_(2)O_(2)^(2+) species,by employing five H-ZSM-5 supports sourced differently with comparable Si/Al ratio.This disparity in Ga_(2)O_(2)^(2+) species stems from their differing capacity in completing the catalytic cycle.Spectroscopic results suggest that PDH proceeds via a two-step mechanism:(1)C-H bond activation of propane on H-Ga_(2)O_(2)^(2+) species(rate determining step);(2)β-hydride elimination of adsorbed propyl group,which only occurs on active Ga_(2)O_(2)^(2+) species corresponding to GaHHW.

Investigation of granite failure precursor under axial load using modified LSTM framework

Granite is usually composed of quartz,biotite,feldspar,and cracks,and the variation characteristics of these components could reflect the deformation and failure process of rock well.Taking granite as an example,the video camera was used to record the deformation and failure process of rock.The distribution of meso-components in video images was then identified.The meso-components of rock failure precursors were also discussed.Moreover,a modified LSTM(long short-term memory method)based on SSA(sparrow search algorithm)was proposed to estimate the change of meso-components of rock failure precursor.It shows that the initiation and expansion of cracks are mainly caused by feldspar and quartz fracture,and when the quartz and feldspar exit the stress framework,rock failure occurs;the second large increase of crack area and the second large decrease of quartz or feldspar area may be used as a precursor of rock failure;the precursor time of rock failure based on meso-scopic components is about 4 s earlier than that observed by the naked eye;the modified LSTM network has the strongest estimation ability for quartz area change,followed by feldspar and biotite,and has the worst estimation ability for cracks;when using the modified LSTM network to predict the precursors of rock instability and failure,quartz and feldspar could be given priority.The results presented herein may provide reference in the investigation of rock failure mechanism.

语言的制度意义——卢梭语言起源问题新论

通过思考语言起源,卢梭发现了“真正的社会”的形成及其特质,由此构成他反思现代社会的理论基础,进而提炼出建构更加合理的社会需要的最珍贵的东西——一种人与人之间心理上的、作为整体的凝聚物——政治德性。这是一种在理性基础上缔结社会契约的最初约定,即个人的意志服从普遍的意志的政治美德。普遍的意志具有超越个体、统一社会的强大力量,在于其普遍性,是人人都会认同的判断和信条。学界以往对卢梭语言著述的研究着重从语言学角度展开,遮蔽了语言与政治制度的隐秘关联,阐明卢梭语言著述的理论内涵,有助于把握卢梭社会理论的整全逻辑。

Synthesis,Cytotoxicity,Apoptosis and Cell Cycle Arrest of a Ruthenium(II)-Substituted Keggin Polyoxotungstate

The ruthenium multi-substituted polyoxotungstate,K_7[Si W_(9)O_(37)Ru_(4)(H_(2)O)_(3)Cl_(3)]·15H_(2)O(S1),was synthesized by a conventional aqueous solution containing the trilacunary Keggin-anionsβ-Na_(9)HSi W_(9)O_(34)·12H_(2)O(S2)and Ru Cl_(3)·n H_(2)O(S3).Compound S1 was charac‐terized by elemental analysis,energy-dispersive X-ray spectroscopy(EDS),thermogravimetric analysis(TG),infrared spectroscopy(IR),uliraviolet visible absorption spectroscopy(UV/Vis)and X-ray photoelectron spectroscopy(XPS).The cytotoxicitycy of S1 was tested in C33A(human cervical cancer),DLD-1(human colon cancer),Hep G2(human liver cancer)and human normal embryonic lung fibroblasts cell(MRC-5).And the viability of these treated cells was evaluated by MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bro‐mide)assay.To explore the mode of cell death induced by S1,morphological study of DNA damage and apoptosis assays were conducted.These analyses revealed that S1 exerted its cytotoxic effect in a dose-dependent manner,primarily triggering apoptotic cell death.Cell cycle analysis by flow cytometry indicated that compound S1 caused cell cycle arrest and accumulated cells in S phase.

The Introduction of the Idea of the Hypothetical Magellanica Continent into China during the Seventeenth Century

The idea of the hypothetical Magellanica Continent(Terra Australis Incognita)was introduced into China by the Jesuit missionaries during the seventeenth century.While not accepted by the Chinese government,it was affirmed and transmitted to the public by a few Chinese scholars,including Feng Yingjing,Cheng Bai'er,Zhang Huang,Xiong Mingyu,Xiong Renlin,You Yi,Zhou Yuqi,Jie Xuan,Wang Honghan,and Ye Zipei.Most of them communicated closely with the Jesuit missionaries,and several even helped the missionaries compose the maps.The concept was updated progressively by Matteo Ricci,Giulio Aleni,Johann Adam Schall von Bell,Francesco Sambiasi,and Ferdinand Verbiest.Chinese scholars copied the missionaries'relevant maps and textual introductions without much modification.However,they paid little attention to advancements in the idea,and many of them circulated outdated knowledge.It was not until the middle-and late-nineteenth century that Chinese scholars reexamined the correctness of this hypothetical continent.

“既然p的话,那么q”句式的或然弱性推断

“既然p的话,那么q”是一种比较特殊的复句句式,属于“推断+假设”的异类组配。“既然”句与“的话”句都属于因果类复句,两者都具有推断性的语义,它们的语义共性推动了接口的产生。同时,说话人的特定表达需要,也对两类复句的异类组配起到了促成作用。在语义接口和语用优先原则的作用下,这两类复句进行了概念整合,重新组配成或然弱性推断句式“既然p的话,那么q”。用以阐释该句式义的或然弱性推断,是汉语复句的固有特征,具有承继性和能产性。此外,假设后置标记进入其他复句前分句末尾,这也意味着同一层次的前后分句之间可能会具有三视点。