Research on the Relationship between the School-Running Characteristics of Private Colleges and Universities and the Development Objectives of the Government

The development objectives of the Chinese government have a guiding effect on the school-running characteristics of private colleges and universities.This paper explores the relationship between the characteristics of private colleges and universities and the development objectives of the provincial government,using Jiangsu Province as a case study.All the schools have the consciousness of fully considering the development objectives of Jiangsu Province when formulating the school-running characteristics.Their characteristics all contain some training methods,training courses,or institutional construction aiming at the development objectives.Most universities can support the government’s objectives on employment and innovation.Only a third of the schools provide government support for science research.Private colleges and universities should make full use of the free and flexible advantages of private education,combine them with the continuous changes of policies and markets,and create clear,scientific,and dynamic school-running characteristics,in order to achieve long-term development.

Preliminary Study on the Nearc-ground Spectral Characteristic of the Degraded Meadow Grassland

IS1921 VF-256 type ground object spectrometer was used to extract the spectral data of the meadow grassland and bare land to obtain their refleotivity spectral characteristics. The experiment was carried out on the low mountain meadow steppe in the Saiwundu Village, Hargentai Town, West Ujumqin Banner, Xilin Gol League, Inner Mongolia. The results showed that different ground objects had different reflectances. The spectral reflectance curve of the meadow steppe plant communities had obvious characteristics of peak and valley in the visible spectrum band, and had strong reflection in the near-infrared band. The reflection curve of the bare lands in the visible spectrum band was higher than that of the meadow grassland communities while inthe near-infrared band it was lower than that of the meadow grassland communities. Under different degradation gradients, the spectral reflectivity of the meadow steppe grassland communities increased with the enhancement of the degradation gradients. Under the same degradation gradient, the Stipa grandis communities had a lower visible light reflectivity than the Artemisia frigida communities but had a higher near-infrared reflectivity than the Artemisia frigida communities; different ground objects on the meadow steppe had different spectrum characteristic, and showed a certain discrepancies with the changes of the degradation level.

Spectral Reflectance Characteristics of Different Snow and Snow-Covered Land Surface Objects and Mixed Spectrum Fitting

The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area.The result showed that for a pure snow spectrum,the snow reflectance peaks appeared from visible to 800 nm band locations;there was an obvious absorption valley of snow spectrum near 1 030 nm wavelength.Compared with fresh snow,the reflection peaks of the old snow and melting snow showed different degrees of decline in the ranges of 300～1 300,1 700～1 800 and 2 200～2 300 nm,the lowest was from the compacted snow and frozen ice.For the vegetation and snow mixed spectral characteristics,it was indicated that the spectral reflectance increased for the snow-covered land types(including pine leaf with snow and pine leaf on snow background), due to the influence of snow background in the range of 350～1 300 nm.However, the spectrum reflectance of mixed pixel remained a vegetation spectral characteristic.In the end,based on the spectrum analysis of snow,vegetation,and mixed snow/vegetation pixels,the mixed spectral fitting equations were established,and the results showed that there was good correlation between spectral curves by simulation fitting and observed ones(correlation coefficient R2=0.950 9).

Burning characteristics of microcellular combustible objects

Microcellular combustible objects for application of combustible case,caseless ammunition or combustible detonator-holding tubes are fabricated through one-step foaming process,in which supercritical CO_2 is used as foaming agent.The formulations consist of inert polymer binder and ultra fine RDX.For the inner porous structures of microcellular combustible objects,the cell sizes present a unimodal or bimodal distribution by adjusting the foaming conditions.Closed bomb test is to investigate the influence of both porous structure style and RDX content on burning behavior.The sample with bimodal distribution of cell sizes burns faster than that with unimodal distribution,and the concentration of RDX can influence the burning characteristics in a positive manner.In addition,the translation of laminar burning to convective burning is determined by burning rate versus pressure curves of samples at two different loading densities,and the resulting transition pressure is 30 MPa.Moreover,the samples with bigger sample size present higher burning rate,resulting in providing deeper convective depth.Dynamic vivacity of samples is also studied.The results show that the vivacity increases with RDX content and varies with inner structure.

Circulations and Thermodynamic Characteristics of Different Patterns of Rainstorm Processes in the Eastern Foot of Helan Mountain

Based on the observational hourly precipitation data and the European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis 5(ERA5)products from 2006 to 2020,22 rainstorm processes in the eastern foot of Helan Mountain are objectively classified by using the hierarchical clustering method,and the circulation characteristics of different patterns are comparatively analyzed in this study.The results show that the occurrences of rainstorm processes in the eastern foot of Helan Mountain are most closely related to three circulation patterns.PatternsⅠandⅢmainly occur in July and August,with similar zonal circulations in synoptic backgrounds.Specifically,the South Asia high and the western Pacific subtropical high are stronger and more northward than those in normal years.The frontal systems in westerlies are inactive,while the water vapor from the ocean surface in the south is mainly transported to the rainstorm area by the southerly jet stream at 700 h Pa.The dynamic lifting anomalies are relatively weak,the instability of atmospheric stratification is anomalously strong,and thus the localized severe convective rainstorm is more significant.Comparatively,rainstorm processes of patternⅠare accompanied by stronger and deeper ascending motions,and the warm-sector rainstorm is more extreme.PatternⅢshows a stronger and deeper convective instability,accompanied by larger low-level moisture.Rainstorm processes of patternⅡmainly occur in early summer and early autumn,presenting a meridional circulation pattern of high in the east and low in the west in terms of geopotential height.Moreover,the two low-level jets transporting the water vapor northward from the ocean on the east of China encounter with the frontal systems in westerlies,which makes the ascending motion in patternⅡanomalously strong and deep.The relatively weak instability of atmospheric stratification causes weak convection and long-lasting precipitation formed by the confluence of cold air and warm air.This study may help improve rainstorm forecasting in arid regions.

FAST COMPUTATION OF WIDEBAND RCS USING CHARACTERISTIC BASIS FUNCTION METHOD AND ASYMPTOTIC WAVEFORM EVALUATION TECHNIQUE

The Asymptotic Waveform Evaluation (AWE) technique is an extrapolation method that provides a reduced-order model of linear system and has already been successfully used to analyze wideband electromagnetic scattering problems. As the number of unknowns increases, the size of Method Of Moments (MOM) impedance matrix grows very rapidly, so it is a prohibitive task for the computation of wideband Radar Cross Section (RCS) from electrically large object or multi-objects using the traditional AWE technique that needs to solve directly matrix inversion. In this paper, an AWE technique based on the Characteristic Basis Function (CBF) method, which can reduce the matrix size to a manageable size for direct matrix inversion, is proposed to analyze electromagnetic scattering from multi-objects over a given frequency band. Numerical examples are presented to il-lustrate the computational accuracy and efficiency of the proposed method.

甲醇-柴油反应活性控制压燃发动机排放特性与经济性预测及优化

基于甲醇-柴油双燃料反应活性控制压燃(reactivity controlled compression ignition,RCCI)发动机台架试验数据,建立了基于粒子群算法(particle swarm optimization,PSO)优化BP神经网络的甲醇-柴油RCCI发动机排放特性、经济性预测智能模型,以发动机负荷、甲醇替代率、EGR率为输入参数,NO_(x)、烟度、CO、THC排放和当量有效燃油消耗率为输出,预测模型的决定系数(R^(2))分别为0.99,0.97,0.99,0.98和0.96,平均绝对百分比误差(mean absolute percentage error,MAPE)为6.46%,0.56%,3.12%,1.21%和0.3%,表明构建的PSO-BPNN模型能够有效预测甲醇-柴油RCCI发动机的NO_(x)、烟度、CO、THC排放和经济性。基于偏最小二乘回归(partial least squares regression,PLSR)分析了不同控制参数对发动机污染物排放和经济性的相关性,将PSO-BPNN预测模型与NSGA-Ⅱ算法相结合,以NO_(x)、烟度和当量有效燃油消耗率为目标对负荷、甲醇替代率和EGR率进行协同优化,将最优控制参数组合标定至双燃料发动机的控制系统进行试验验证。结果表明:优化后烟度变化不明显,NO_(x)排放平均降低39.6%,当量有效燃油消耗率平均降低2.6%。

整体主观偏好与嗜好性感官属性客观量化间的感知交互

为探讨消费者主观偏好测试对其随后进行的感官品质客观量化评价的影响,尤其是"嗜好性感官特征"的客观量化,本文采用蛋白粉和调制奶两种溶液体系,分别对202名消费者进行喜好度、适宜度(Just-about-right,JAR)测试和对175名消费者进行喜好度和强度排序-评分测试,并对比消费者与专业评价员对各嗜好性感官特性的量化结果差异。结果显示:在蛋白粉体系中,评价员对稠厚度的评分随着样品风味强度的增强而下降(P<0.05),而顺滑感无显著变化(P>0.05),然而,消费者的评价并未呈现相同趋势。在牛奶体系中,评价员对乳脂感的强度评价受到脂肪和蔗糖浓度的共同影响,消费者的感知与此结果并不一致。进一步分析发现,两个测试中,消费者对嗜好性属性的量化评分均与其对样品的整体主观偏好程度高度相关,即整体喜好度越高的样品,对应的嗜好性属性强度评分越高。本文研究消费者偏好与感官属性之间的关系,为获得全面客观的消费者评价而设计可靠有效的消费者测试方法提供了有力的理论依据。

基于Transformer的跨尺度交互学习伪装目标检测

伪装目标检测(COD)旨在精确且高效地检测出与背景高度相似的伪装物体,其方法可为物种保护、医学病患检测和军事监测等领域提供助力,具有较高的实用价值.近年来,采用深度学习方法进行伪装目标检测成为一个比较新兴的研究方向.但现有大多数COD算法都是以卷积神经网络(CNN)作为特征提取网络,并且在结合多层次特征时,忽略了特征表示和融合方法对检测性能的影响.针对基于卷积神经网络的伪装目标检测模型对被检测目标的全局特征提取能力较弱问题,提出一种基于Transformer的跨尺度交互学习伪装目标检测方法.该模型首先提出了双分支特征融合模块,将经过迭代注意力的特征进行融合,更好地融合高低层特征;其次引入了多尺度全局上下文信息模块,充分联系上下文信息增强特征;最后提出了多通道池化模块,能够聚焦被检测物体的局部信息,提高伪装目标检测准确率.在CHAMELEON、CAMO以及COD10K数据集上的实验结果表明,与当前主流的伪装物体检测算法相比较,该方法生成的预测图更加清晰,伪装目标检测模型能取得更高精度.

基于DMOEA-APTC算法的无人机在线航迹规划

为了解决具有时间关联性质的动态多目标优化问题,以无人机在线航迹规划问题为基础,引入时间关联特征概念并建立无人机时间关联动态多目标优化问题模型,提出一种使用自适应预测响应机制和时间关联性优化机制的动态多目标双层优化算法。根据环境变化相关性判断环境变化强弱并启用不同响应机制,快速适应环境变化;优化过程中通过最小二乘法学习历史数据拟合航迹未来预测值,根据预测可靠性自适应选择“仅优化当前”或“同时优化当前与未来”优化模式;使用改进后的切比雪夫分解法对符合偏好的航迹进行决策。实验结果表明:所提算法在复杂飞行环境下降低飞行时长的同时具有更高生存概率,提高了无人机飞行稳定性,更合理有效地处理了在线航迹规划问题。

基于分数阶黏弹性缓冲系统的代理模型可视化研究

分数阶黏弹性缓冲系统模型可以准确描述黏弹性材料的力学性质,被广泛应用于工程车辆的减振控制中。但由于模型本身的复杂度使得在求解及优化过程中消耗大量的时间和计算成本,而代理模型很好地解决这一问题。通过引入图形用户界面(GUI)技术,开发出一种用户友好的复杂分数阶代理模型可视化实验系统,该系统主要包含实验设计模块、代理模型模块和误差分析模块3大模块。使用时根据需求选择不同的分数阶及代理模型,输入变量取值范围信息,即可得到代理模型拟合效果图以及误差,然后对比分析不同代理模型的误差结果,选择拟合效果最好的代理模型。以Maxwell分数阶模型为例,在同等变量选择范围下分析4种代理模型获得的代理效果。结果表明:当施加外力在0~100 N,系统固有频率在0~100 Hz的条件下,决定系数为0.989 7,均方根误差为0.146的混合自适应代理模型为拟合效果最好的代理模型。此系统的开发为代理模型在分数阶黏弹性缓冲系统的计算及优化研究中提供一定的应用价值,解决了复杂分数阶求解计算成本大的问题。

基于MEA-BP神经网络的多孔质轴承参数优化

为了提高圆盘类多孔质静压止推轴承的静态特性,采用思维进化算法(MEA)优化反向传播(BP)神经网络,创建圆盘类多孔质静压止推轴承静态特性的预测模型,完成轴承静态承载力、静刚度以及耗气量的高精度预测,其预测误差分别低于2%、5%以及5%。基于此模型,以最大化静态承载力和静刚度、最小化耗气量为优化目标值,采用遗传算法对轴承的多孔质参数组合进行多目标优化,实现轴承参数的快速优化设计。优化结果表明:此轴承静态承载力提高了64.53%,静刚度提高了31.93%,耗气量降低了56.52%。

基于深度学习的SAR弱小目标检测研究进展

随着合成孔径雷达(SAR)技术的不断进步,大范围观测和高分辨率成像使得SAR图像中包含了大量特征微弱的小尺寸目标,通常涵盖飞机、车辆、油罐、船舶等高价值民用目标和关键军事目标,这类目标尺寸较小、特征微弱、稠密相连、形态多变,对它们进行精确的检测是当前SAR图像解译的难题.随着深度学习技术的发展,研究者们针对SAR弱小目标的成像特性和检测挑战,通过对深度学习网络的精细调整和优化,成功地推动了本领域的进步.本文将全面回顾基于深度学习的SAR图像弱小目标检测,以数据集和方法为研究对象,深入分析SAR弱小目标检测任务所面临的主要挑战,总结最新检测方法的特点和应用场景,并汇总整理了公开数据集与常用性能评估指标.最后,总结本任务的应用现状,并对未来的发展趋势进行展望.

谐波环境下模块化多电平换流器子模块电容器的多场耦合分析及优化研究

金属化薄膜电容器作为柔性直流输电用换流阀的核心设备,在大谐波分量与高环境温度的复杂多物理场作用下存在异常温升、鼓包形变等问题,严重影响着电容器的使用寿命。该文建立了金属化薄膜、电容器单体与电容器整机的电-热-力多场耦合模型,分析了模块化多电平换流器子模块常见谐波环境下,电容器内部多物理场特性。发现谐波电流增强了电容器层间电场畸变与金属化层的欧姆损耗,谐波电场的叠加增大了基膜的介质损耗,综合导致了电容热点温度与内部应力值在谐波分量的增大下呈指数形式上升。为改善电容器在谐波环境下的运行稳定性,采用多目标粒子群算法对单体电容的结构参数进行了优化,得到了单体结构最优解:膜厚4.7mm,膜宽41.8mm,电容直径40.6mm。优化后电容器内部电场畸变系数、热点温度与最大应力值分别降低了23%、22%与31%。提高了电容器在谐波环境下的工作性能,对提升其运行可靠性有一定的指导意义。

基于BPNN和MOOGA的高速联轴器多目标优化方法

针对高转速、复合工况下膜盘联轴器难以保证其强度特性问题,对已有膜盘联轴器强度及动力学特性进行了研究,提出了一种基于反向传播神经网络(BPNN)和多目标优化遗传算法(MOOGA)的高速联轴器多目标优化方法。首先,为了得到优化所需的关键参数,采用了正交实验结合多因素方差分析的方法,选取了联轴器优化参数;然后,基于已选取的关键参数,采用BPNN方法构建了截面应力和弯曲刚度的目标函数,并将其与多项式拟合方法进行了对比,对BPNN方法的精确性进行了验证;最后,采用MOOGA方法对目标函数进行了多目标优化,并将优化前后结果进行了对比分析。研究结果表明:采用BPNN结合MOOGA的方法对联轴器设计参数进行优化,在满足联轴器刚度需求的情况下,可有效降低联轴器膜盘的危险截面应力;优化后,联轴器危险应力减小了18.2%,弯曲刚度降低了5.05%,联轴器角向补偿能力增加了0.1°,从而证明了仿真的有效性。该结果可以为挠性联轴器参数优化设计提供参考。

颈围对四川省保健对象代谢综合征的预测价值

目的探讨四川省保健对象颈围预测代谢综合征最佳分界值及预测风险。方法对2015年1月至2019年12月年在我院行健康体检的3345例四川省保健对象的资料进行分析。代谢综合征根据2004年中国糖尿病协会的标准诊断。结果四川省保健对象的颈围与体重指数及腰围显著相关(P<0.01)。ROC曲线分析提示颈围预测代谢综合征的最佳临界值,男性为37 cm,女性为33 cm。在调整了年龄、吸烟、饮酒、运动、民族因素后,Logistic回归分析提示,颈围分界值以上比颈围分界值以下,MetS风险男性增加5.107倍,女性增加6.102倍。结论颈围是代谢综合征的独立危险因素,可以作为辅助筛查四川省保健对象MetS的人体测量指标,尤其是位于颈围最佳分界值以上的人群,其代谢综合征的风险成倍增加。

迷宫流道流阻特性研究与优化设计

迷宫流道流阻特性的设计是迷宫式调节阀实现节流减压的关键。然而,迷宫流道结构较为复杂,流动介质中的沉积物易导致迷宫流道堵塞,影响节流减压性能。对迷宫流道的流阻性能和抗堵塞性能进行研究,分析不同结构迷宫流道的流场与颗粒运移规律,并优选特斯拉形作为基础迷宫流道结构。通过正交试验设计,阐明了特斯拉形流道结构参数与流阻系数、颗粒通过时间之间的影响关系,并建立多元非线性回归模型。采用基于NSGA-II的多目标优化算法,以流阻系数最大、颗粒通过时间最小为优化目标进行高流阻低堵塞迷宫流道优化设计。结果表明:特斯拉形迷宫流道宽度和深度的减小可以增大流阻系数,出口段长度的减小可以降低颗粒通过时间;优化后特斯拉形迷宫流道流阻系数提高了55.3%,颗粒通过时间降低了1.58%,有效的提升了流阻特性和抗堵塞性能。

噪声特性对言语可懂度评价的影响

言语可懂度是语言声房间和厅堂音质评价的重要指标,噪声特性是影响言语可懂度评价结果的重要因素之一。基于国内外相关文献就噪声特性对言语可懂度评价的影响进行系统研究,结果表明,噪声特性对言语可懂度的评价结果有显著影响(:1)噪声在时域上的波动起伏有利于言语理解,但会导致个体间差异增大并降低评价结果的稳定性;噪声频率范围和频谱分布与语言声越接近,在低频区的噪声量越大,对言语可懂度的影响越大;言语噪声能够导致额外的信息掩蔽,影响程度与言语噪声的数量、噪声和目标语之间的相似程度以及听者的个体因素等有关。(2)将当前基于稳态噪声的言语可懂度客观评价方法用于其他噪声时,可能造成对言语可懂度的低估或高估。非稳态噪声情况下的可懂度客观评价仍存在一些不确定的地方。结合当前的研究现状,进一步提出该领域的下一步研究方向。相关内容可为噪声环境中的言语可懂度主、客观评价提供参考。

基于非线性空气弹簧模型的整车仿真与主客观评价

应用非线性空气弹簧模型,研究了空气悬架整车的动力学仿真和主观评价。结合空气弹簧频率、振幅相关性模型与Simulink仿真,给出了空气悬架整车7自由度模型,对比了不同路面情形下悬架动行程和簧上加速度的均方根值和功率谱密度。从时域和频率2个角度分析了不同速度、路面及减振器阻尼情形下空气悬架整车的动态特性。对装有不同空气弹簧的整车进行主、客观试验测试。结果表明:悬架动行程预测误差小于7%,簧上位置加速度共振峰值预测误差小于6%,共振频率预测误差小于6%;从而验证了所提模型的普适性和精确性;反映了带空气悬架整车的动态特性,解释了平顺性主客观试验的机理。

低压直流固态断路器分断特性优化方法研究

为提高在直流系统发生短路故障时固态断路器(SSCB)的分断能力,提出一种考虑分断特性的低压直流固态断路器参数多目标优化方法。首先对短路故障时SSCB的分断流程进行详细分析,通过理论与仿真确定了限流电感LB和金属氧化物压敏电阻的限电压能力系数γ对分断特性的影响。以分断特性为基础,建立了SSCB的分断冲击性能指标、分断时间指标、能量吸收指标三个优化目标函数,通过多目标粒子群算法对目标函数进行优化,采用结合决策者偏好的逼近于理想解的排序方法对优化方案进行决策。优化结果表明,在各种决策者偏好下的优化方案,其优化设计后的元件参数LB和γ均能显著提高SSCB的分断性能。