ON THE BOUNDEDNESS AND THE STABILITY PROPERTIES OF SOLUTION OF CERTAIN FOURTH ORDER DIFFERENTIAL EQUATIONS

This paper investigates equation (1) in twocases:(i)P=0, (ii)P satisfies|P (i,x,y,z,w)<(A+|y|+|z|+|w|)q(t).whereq(t) is a nonnegative function of t. For case (i) the asymptotic stability in the large of the trivial solution x=0 is investigated and for case (ii) the boundedness result is obtained for solutions of equation (1). These results improve and include several well-known results.

Higher-order squeezing of quantum field and higher-order uncertainty relations in non-degenerate four-wave mixing

It is found that the field of the combined mode of the probe wave and the phase conjugate wave in the process of non-degenerate four-wave mixing exhibits higher-order squeezing to all even orders. The higher-order squeezed parameter and squeezed limit due to the modulation frequency are investigated. The smaller the modulation frequency is, the stronger the degree of higher-order squeezing becomes. Furthermore, the hlgher-order uncertainty relations in the process of non-degenerate four-wave mixing are presented for the first time. The product of higher-order noise moments is related to even order number N and the length L of the medium.

设计秩序中的修辞

设计秩序中的修辞被认为是感官评价的重要因素,但该理论的完整性严重缺失。视觉修辞和设计即修辞理论常以模糊的方式反复出现。修辞引入意义远大于其作为诠释功能的理解,导致相关研究难以深入。通过梳理设计问题演变与修辞学之间的关系,探讨体验系统中设计与修辞关系的变化,为设计修辞的研究提供理论结构与焦点参考。

全液压旋挖扩底钻孔灌注桩质量管控措施研究

扩底灌注桩是一种混凝土灌注桩,是在进行原有灌注桩施工的基础上对桩底进行扩底处理,从而增加灌注桩的承载力和稳定性。在工程地质条件差特别是软土地基,施工难度大,施工中易产生如塌孔等质量问题,为了避免在采用全液压旋挖扩底钻孔灌注桩施工时,因现场技术质量管理措施不到位而出现桩身质量差、进度滞后等问题,本文针对其质量管控措施进行研究,采取扩底灌注桩施工工艺、制定“四令”精细化过程管理原则、计算注浆施工所需水泥浆量等方法,优化了工程施工流程,严格各施工环节质量管理,确保全液压旋挖扩底钻孔灌注桩施工安全、质量提升。

元件服从广义四参数BS分布的串联和并联系统寿命的随机比较

Birnbaum-Saunders疲劳寿命分布可用于描述因疲劳导致失效的产品的寿命特征,该分布已经成为可靠性统计分析中的常用分布之一。首先基于广义三参数BS分布,通过引入位置参数μ,得到广义四参数BS分布GBSII(α, β,μ, k);其次,以服从广义四参数BS分布的独立元件寿命为主体,研究它构成的串联系统和并联系统寿命的随机比较。分析结果可以更好地拟合失效产品的寿命规律。

基于四象限储能功率线性化模型的配电网协同优化

针对高渗透光伏可能引发配电网净负荷形态转变、电压越限和网损增加等问题,提出了一种考虑四象限储能功率线性化建模的主动配电网有功功率-无功功率协调优化策略。首先,分析主动配电网各类型调控资源的有功功率-无功功率调节能力和运行特性,特别是光伏和储能功率运行边界,基于此,提出四象限储能功率调节的线性化建模方法。然后,考虑储能功率容量约束和能量容量约束,构建配电网协同优化模型的目标函数和约束条件,并通过二阶锥松弛算法进行求解。最后,利用改进后的IEEE33节点系统验证所提方法的有效性和可行性。

空间运动方程快速求解器设计与实现

文章基于四阶经典龙格库塔法(classical Runge-Kutta method of order four,RK-4)和四阶Adams预测校正法(fourth-order Adams predictor-corrector method,Adams-4),提出一种现场可编程逻辑门阵列(field programmable gate array,FPGA)实现的数据路径可动态配置的空间运动方程快速求解器(space motion equation fast solver,SMEFS)。SMEFS采用折叠式结构,借助高效的任务映射和精准的状态管理,通过资源复用和动态配置运算器内部连接关系实现数据路径的动态配置,快速求解空间运动方程,并有效节省硬件资源。采用某型运载火箭的相关数据对SMEFS进行大批量空间运动方程求解的性能评估,实验结果表明SMEFS能够快速可靠地求解发射坐标系下的五自由度空间运动方程,与软件求解的平均加速比为12.765,求解结果最大相对误差小于9×10^(-5,)具备较好的加速效果和较高的计算可靠性。

先秦时间观念的多元化审美特质:以“三礼”为中心

先秦时期是中国传统时间审美观念的奠基期。然而,学界或从中西对比层面,或从阐释学和现象学维度,或从先秦单本原典以及“三礼”具体篇目入手,又或专注于时间审美与人类礼俗、艺术创作、儒释道文化的关系等进行研究。整体观之,直接涉及“三礼”具体内容以及先秦基于中国传统时间观念奠基作用的研究尚显不足。综合文献分析、归纳演绎和跨学科研究等方法,通过梳理和探析“三礼”时间观念审美特性的内涵及其成因,可发掘出“三礼”是以早期巫祭意识、农耕文明形塑出的自然经验以及《周易》、老子等对时间的哲学建构为基础,从而形成了融合自然神性之美、循环往复之美、生生之德美为一体的时间观念审美特性,这亦可证实先秦时间观念的多元化审美特质。不同于以往研究,以“三礼”为中心来切入先秦时间观念的审美特质,不仅对整体理解和具象把握先秦时间观念的审美特质起到重要的参照作用,还可使得时间观念在先秦美学中的重要地位得以凸显。更进一步,亦可由此窥见“三礼”乃至先秦时间观念的多元化审美特质不只是建基于伦理纲常和等级位序等道德观念之上,其更深层地是源发于对自然时间秩序观念的审美观照。

城市更新中文脉延续及空间重塑在青年广场设计中的实践

城市更新项目作为推动城市发展的重要手段,其核心在于实现经济、社会、文化的均衡发展。为此,结合城市有机更新理念的演变及其在新时代的要求,强化历史价值修复、人文景观释放、社会价值激活、空间秩序重建以及场地条件梳理等关键设计理念。同时,以“两江四岸”青年广场设计为例,指出持续优化与动态配合在城市更新实施过程中的重要性,并为城市更新项目的设计与实践提供理论支持和实践参考,以推动城市更新设计的有序进行和持续发展。

五育融合视域下“双元三阶四化”式教育研究——以高职数控专业为例

本研究通过深入探讨“五育”融合对高职数控专业可持续发展的影响,对学生“德技并修,一专多能”的全面发展,具有重大意义。通过“双元三阶四化”的实践路径研究,着力打造校企“双元”,建设双师型教学团队,明确教学目标,丰富课程设置,衔接“岗课赛证”,提升技能水平,构建专业“四化”,助推职普融通、产教融合、科教融汇。为深化教学改革,探索教学模式多元化,促进“五育”渗透高职数控专业,为“新质生产力”输送高素质技能人才,提供理论支持和发展建议以及人才培养模式改革。

基于积分滑模控制的四开关三相Cuk逆变器研究

此处提出一种基于Cuk变换器拓扑结构的四开关三相(FSTP)逆变器设计方案,称之为FSTPCuk逆变器。首先分析了FSTPCuk逆变器的拓扑结构,然后推导了Cuk变换器的四阶模型,并将其简化以适用积分滑模控制器(ISMC)。在简化系统模型的基础上,设计了由等效控制部分和开关控制部分组成的ISMC,并将其应用于FSTPCuk逆变器。最后,通过试验装置对所提出的概念进行了验证。试验结果表明了该逆变器的有效性。该拓扑结构能够提供纯正弦输出电压。与传统的FSTP逆变器相比,FSTPCuk逆变器提高了输入直流电源的电压利用率,提供了更高的输出线电压,可以扩展到直流输入电压的全值。采用积分滑模控制,以优化系统的动态特性,能够保证系统在不同工况下的鲁棒性。

Synthesis of Poly (3-acetylpyrrolyl methine) with Azobenzene Side Groups and Study on Its Third-order Nonlinear Optical Property

A novel soluble π-conjugated polymer, poly [（3-acetylpyrrole-2, 5-diyl） p-（N, N-dimethylamino） azobenzylidene] （PAPDMAABE）, was synthesized by condensation of 3-acetylpyrrole with 4-aldehyde-4＇-dimethylaminoazobenzene （ADMAA）. The chemical structure of PAPDMAABE was characterized by Fourier transform infrared spectroscopy （FTIR）, ^1H-NMR, and UV-Vis-NIR spectra. Transmission electron microscope （TEM） analysis for PAPDMAABE indicates that part of PAPDMAABE is in crystal state, due to the short-range order of the polymer. Thermogravimetric analysis （TGA） curve shows that the polymer has good thermal stability and its decomposition temperature is 248℃. The optical band gap of PAPDMAABE obtained from the optical absorption spectrum is about 1.73 eV. The resonant third-order nonlinear optical property of PAPDMAABE at 532 nm was studied using degenerate four-wave mixing （DFWM） technique. The resonant third-order nonlinear optical susceptibility of the polymer is about 7.48×10^-8 esu.

Four-mode continuous-variables entangled state:generation from beam splitter,a parametric down-conversion and a polarizer

We introduce a new kind of four-mode continuous variable entangled state in Fock space. The completeness relation and the partly nonorthonormal property of such a state are proven. The scheme to generate this state is presented by combining a symmetrical beamsplitter, a parametric down-conversion and a polarizer. After making a single-mode quadrature amplitude measurement, the remaining three modes are kept in entanglement. And its applications are also discussed.

M^2 factor of four-petal Gaussian beam

Based on the second-order moments, this paper derives an analytical expression of the M^2 factor of four-petal Gaussian beam. The results show that the M^2 factor is only determined by the beam order n. The corresponding numerical calculations are also given. As the beam order increases, the augment of M^2 factor is disciplinary. As the expression of M^2 factor is expressed in series form and becomes more complicated, a new concise formula of M^2 factor is also presented by using curve fitting of numerical calculations. When 3 ≤ n ≤ 200, the maximum error rate of fitting formula will not exceed 2.6% and the average error rate is 0.28%. This research is helpful to the applications of four-petal Gaussian beam.

THIRD ORDER NONLINEAR OPTICAL PROPERTIES OF PERNIGRANILINE SOLUTION IN CONCENTRATED SULFURIC ACID

The fully oxidized state of polyaniline (PANI), pernigraniline (PN), was synthesized by oxidation of the emeraldine base form of PAM dissolved in NMP solvent with m-chloroperoxybenzoic acid. The resulted PN was characterized by FTIR and UV-Visible spectra. The third-order nonlinear optical properties of PN in concentrated sulfuric acid (PN/H2SO4) were measured by a degenerated four wave mixing (DFWM) method. The results obtained suggest that the soliton-pair intermediate state associated with the degenerated state does not play a major role in the third order nonlinear optical properties of PANI.

济阳坳陷陆相页岩油气藏组合缝网高导流压裂关键技术

济阳坳陷页岩油气藏具有埋藏深、构造复杂、沉积相变化快、纹层发育、原油黏度高等复杂特征,采用常规缝网压裂技术时改造效果普遍不理想、压后产量低且衰减快,亟待攻关能形成与之相适应的长期高导流能力复杂缝网的压裂新技术。为此,基于地质工程一体化思路,开展了地质—工程双甜点评价、四级组合缝网构建、主裂缝脉冲加砂理论与技术研究,形成了组合缝网高导流压裂关键技术,并实现了规模应用。研究结果表明:①充分考虑页岩油气富集、可动性、页岩纹层发育情况等特征,建立了考虑“岩屑—岩心—井眼—储层”的“地质—工程”双甜点评价模型,井位布置、压裂层位及射孔位置优选更加精准;②构建了CO_(2)与酸液联合降低破裂压力,低黏度压裂液造复杂缝、高黏度压裂液促缝高的组合压裂液新模式,增加了压裂后缝网的复杂性;③形成了多层叠置储层压裂后的“大缝宽主裂缝+分支裂缝+自支撑裂缝+酸蚀蚓孔缝”四级组合缝网体系,提出了主裂缝脉冲加砂、分支裂缝连续加砂的高导流缝网加砂压裂新方法,提升了缝网的长期导流能力。结论认为,“双甜点布缝+CO_(2)与酸液降破促缝+压裂液变黏高黏+主裂缝脉冲加砂”的组合缝网高导流压裂关键技术,促进了济阳坳陷陆相页岩油气藏的高黏度原油经济高效开发,为类似地区页岩油气藏的改造提供了理论与技术参考。

Synthesis of Poly[(3-octanoylpyrrole-2,5-diyl)-p-nitrobenzylidene] and Its Third-order Nonlinear Optical Property

A novel soluble π-conjugated polymer, poly[(3-octanoylpyrrole-2,5-diyl)-p-nitrobenzylidene] (POPNBE), was synthesized by a five-step reaction. As a result of introducing a long acyl to pyrrole at 3-position, the polymer can be easily solved in polar solvents and be processed into films. The chemical structures of the intermediates and POPNBE were characterized by FTIR, 1H NMR, and UV-Vis-NIR spectrometries. The absorption band in the range of 400-600 nm in the UV-Vis-NIR spectrum is due to the π-π * band gap transition. The optical band gap of POPNBE obtained from the optical absorption is about 1.72 eV. The resonant third-order nonlinear optical property of POPNBE at 532 nm was studied by using the degenerate four-wave mixing(DFWM) technique. The resonant third-order nonlinear optical susceptibility of POPNBE is about 3.42×10 -8 esu.

基于内摆线原理设计的四缸汽油发动机惯性力分析

使用曲柄连杆机构的传统四缸汽油发动机在运行时会产生二阶往复惯性力,导致发动机的振动较大。为了解决该问题,基于内摆线原理设计出一种新型四缸汽油发动机。对该发动机的惯性力进行了理论分析,并使用Adams软件进行了仿真验证。结果表明:四缸内摆线汽油发动机在一阶往复惯性力和旋转惯性力达到平衡的同时,不会产生二阶往复惯性力,有效降低了发动机的振动。

基于带宽调整的两种混合载波跟踪环路研究

针对高动态导致载波复现频率与实际载波频率相差较大的问题,锁频环和锁相环已无法满足环路的跟踪需求,依据频率判决因子实现三阶锁频环辅助四阶锁相环和四相鉴频器之间相互切换的2种混合载波跟踪环路算法;在三阶锁频环辅助四阶锁相环的基础上,通过相位判决因子完成对载波环带宽的动态调整。结果表明,在动态为5000/150 g/120 g、载噪比为42 dB/Hz、跟踪初始多普勒为300 Hz时,基于带宽调整的2种混合载波跟踪环路能准确地剥离出电文信息,而单一的三阶锁频环辅助四阶锁相环载波跟踪环路不能实现;当跟踪初始多普勒为0时,环路稳定跟踪后加入25/20 g/20 g的动态,基于带宽调整的2种混合载波跟踪环路可以重新完成稳定跟踪并剥离出电文信息,而三阶锁频环辅助四阶锁相环载波跟踪环路直接失锁;低载噪比下的基于带宽调整的2种混合载波跟踪环路的跟踪相位误差方差相对较小、跟踪精度较高。

“四创五改”教育改革示范建设

为更好地贯彻落实国家高等教育相关战略要求,主动适应和引领新一轮科技革命和产业变革,我院掀起了关于四创教育改革建设示范工作,针对本院智慧旅游专业学生开展了关于“四创五改”的教育改革。重点培养学生四创意识,结合高阶思维能力训练,从理论教学、实践教学、教学方法、引导学生开展课外实践创新活动、考核办法五个方面展开针对性教育改革。通过改革,学生对本课程兴趣度更高,实践动手及创新能力得到了明显改善。