基于温度梯度的锂离子电池寿命衰减情况的研究

在实际车辆运行工况下,电池包内电池的温度分布呈现出不均匀的特征,且在较高工作温度下电池的衰减速度会加快,可能促使容量和功率的减退加速。以锂离子电池为研究对象,通过对电池组进行长周期的1 C充放电循环,对电池组的温度分布、衰减情况以及电流分布行为进行了系统的表征和分析,并将其与单个基准电池进行了对比。研究结果显示,电池组中的所有电池都经历了更高的温度上升,且衰减速度较基准电池更快。尤其值得注意的是,经过1815个循环后,电池组中间的电池容量减退至初始容量的61.2%,而基准电池的容量保持率为86.5%。此外,电池组中的电阻和电流也呈现了类似的变化趋势。通过实验性地量化非均匀温度分布对电池衰减的影响,有助于更深入地理解在存在温度梯度情况下模块化锂离子电池的衰减行为。这对于优化电池设计、提高电池性能和延长电池寿命具有重要的指导意义。

深V型滑行艇横摇阻尼的实验确定

对深V型滑行艇模型进行了静水横摇衰减实验和零速正横浪规则波中横摇运动实验,讨论了在处理试验数据时所面临的一些问题;采用分段最小二乘拟合法对静水横摇衰减实验曲线进行光顺,用峰值处理法计算不同横摇角时的横摇阻尼,并进行多项式回归得到深V型滑行艇横摇阻尼公式.

光纤布拉格光栅的热致衰减研究

光纤布拉格光栅的工作寿命是影响光纤光栅传感器性能的关键因素。从光纤布拉格光栅的热致衰减特性出发,以界面阻隔能模型为理论基础,以光纤光栅的反射峰值为研究对象,探讨了光纤布拉格光栅的热致衰减行为。并通过对比试验对3支不同的光纤布拉格光栅进行了600℃热加速衰减实验,初步证明即使进行了退火处理,光纤布拉格光栅的性能仍然存在热致衰减蜕化。从实验数据中得到了光纤布拉格光栅的热振动频率,建立了热致衰减曲线。预测了30℃、50℃、100℃条件下光纤布拉格光栅的反射率衰减到90%的时间分别为23年、11年和3年。

影响煤制乙二醇紫外透光率因素实验分析

影响乙二醇产品紫外透光率物理因素有空气、氮气和阳光照射,为探讨各物理因素对乙二醇产品紫外透光率衰减程度影响,利用氮气和空气分别对乙二醇产品做鼓泡实验、阳光照射和空气中静置乙二醇产品实验,结果表明,乙二醇产品在氮气环境中,紫外透光率衰减最慢,在空气鼓泡环境中,紫外透光率衰减最快。影响乙二醇产品紫外透光率化学因素有精馏系统加碱、精馏系统不加碱、乙二醇加氢反应、树脂质量提升,为探讨各化学因素对乙二醇产品紫外透光率衰减影响程度,对4种化学处理后得到乙二醇产品做空气鼓泡衰减实验,结果表明,乙二醇加氢后产品紫外衰减最慢,精馏系统不加碱紫外衰减最快。

高温老化后嵌入式共固化阻尼复合材料结构的阻尼性能

在综合研究双马来酰亚胺树脂基碳纤维预浸料(T700/QY260)和AFLAS氟橡胶的力学性能、阻尼性能和耐高温性能基础上,通过试验的方法提出一种能够耐260℃超高温度的黏弹性阻尼材料。利用四氢呋喃溶液将该黏弹性阻尼材料制成阻尼胶浆溶液,结合双面刷涂和热压罐工艺制备出嵌入式共固化阻尼复合材料试件,利用自由振动衰减实验方法对该试件分别做常温、230℃*96 H、260℃*96 H老化实验处理后相对阻尼系数的测定,得到不同温度老化处理后的嵌入式共固化阻尼复合材料的相对阻尼系数与阻尼材料厚度的关系,证明了所制备的嵌入式共固化阻尼复合材料具有优异耐超高温性能和稳定的阻尼性能。

EXPERIMENTAL STUDY ON DARCY′S LAW IN HELE-SHAW CELLS

The basic physics of unsteady Hele-Shaw flow at high Reynolds numbers is mainly studied by an experimental measurement. In order to confirm the Darcy′s law in Hele-Shaw cell, since there is an analogy between flow in cells and that in porous media, progressive water waves are utilized to build an unsteady flow in a Hele-Shaw cell, and which complex wave number is measured by a wave height gauge. Meanwhile, theoretical analyses are used to compare with experimental data. Result shows Darcy′s Law is not exactly correct for unsteady Hele-Shaw flows, and it is expected to conduct a modified Darcy′s Law.

清洁度检测空白值的试验分析

通过对清洁度空白值的学习和实践,掌握清洁度检测空白值确定原则、方法和流程,确定空白值和满足允许的空白值限值,验证清洁度标准和杂质提取方法的合理性,确保了清洁度检测是在充分洁净的检测系统和环境条件下进行的,同时也保证了检测过程中引入的非出自试样本身的污染不会影响检测结果。

Forecast correct model of overpressure attenuation during gas explosion in excavation roadway

Through analyzing experimental data of gas explosions in excavation roadwaysand the forecast models of the literature, Found that there is no direct proportional linearcorrelation between overpressure and the square root of the accumulated volume of gas,the square root of the propagation distance multiplicative inverse.Also, attenuation speedof the forecast model calculation is faster than that of experimental data.Based on theoriginal forecast models and experimental data, deduced the relation of factors by introducinga correlation coefficient with concrete volume and distance, which had been verifiedby the roadway experiment data.The results show that it is closer to the roadway experimentaldata and the overpressure amount increases first then decreases with thepropagation distance.

Study on B_d→φK_s Decay in EDQS Model

We study Bd → φKs decay in extra down-type quarks （EDQS） model with a non-universal Z boson associated with flavor changing neutral currents （FCNCs） at the tree level. With the up-to-date experimental data of Br（Bd → φKs）, SCKs, and ACKs, we derive the bounds on the Z-b-s coupling parameter ｜Ubs ｜ and the new weak phase φ, using the constrained parameter spaces, we finally give predictions for Bd → φφ decay, which could be tested at the Fermilab Tevatron and the LHC-b experiments.

Novel Algorithm for Active Noise Control Systems Based on Frequency Selective Filters

A novel algorithm for active noise control systems based on frequency selective filters （FSFANC） is presented in the paper. The FSFANC aims at the multi-tonal noise attenuation problem. One FSFANC system copes with one of the tonal components, and several FSFANC systems can run independently in paralld to cancel the selected multiple tones. The proposed algorithm adopts a simple structure with only two coefficients that can be explained as the real and imaginary parts of the structure to model the secondary path, and estimates the secondary path by injecting sinusoidal identification signals. Theoretical analysis and laboratory experiments show that the proposed algorithm possesses stone advantages, such as simpler structure, less computational burden, greater stability, and fast converging speed.

Failure behavior of cellular titanium under dynamic loading

The dynamic compressive deformation of cellular titanium with regularly distributed cylindrical pores is investigated to evaluate the effect of shock attenuation and obtain the shock Hugoniot relationship of the material. Dynamic compression experiments are conducted at room temperature using a single-stage light gas gun. The Hugoniot relations between shock wave velocity and particle velocity for the cellular titanium samples with porosities 20% and 30% are obtained. The shock response of the regular cellular titanium shows a clear wave attenuation effect. Numerical simulations are also conducted to supplement the experimental study.Inelastic deformation is observed in the samples using optical micrographs, indicating that the deformation of pores contributes significantly to the shock wave attenuation of the cellular titanium material.

Protecting Distribution Entanglement by Weak Measurement and Reversal under Various Decoherence Sources

Protection of entanglement from disturbance of the environment is an essential task marion processing. We examine the validity and limitation of the weak measurement and reversal in quantum infor- （WMR） operation in the protection of distributed entanglement from various decoherence sources. Since the entanglement variation can be investigated analytically for an arbitrarily entangled bipartite pure state under three kinds of typical noisy quantum channels, we show explicitly that the WMR operation indeed helps for protecting distributed entanglement from ampli- tude damping and phase damping, but not for depolarizing. Bxperimental feasibility for testing our results is discussed using current laboratory techniques.

Branching fractions and direct C P asymmetries of ■_s →K^0h^+h′^-(h(′)=K,π) decays

Motivated by the recent LHCb collaboration measurements of charmless three-body decays of Bs-0 meson, we calculate the branching fractions of Bs→K0h＋h＇-（h（＇）=K,π）decay modes using the factorization approach.Both the resonant and nonresonant contributions are studied in detail. For the decays Bs→K0h＋h＇-（h（＇）=K,π） and Bs→K0h＋h＇-（h（＇）=K,π）our resultsagree well with experimental data, and the former is dominated by the K＊, while the latter one is dominated by the nonresonant con-tribution. Considering the flavor S U（3） symmetry violation, the sum of branching fractions of Bs→K0h＋h＇-（h（＇）=K,π）could accommodate the data well too. It should be noted that both branching fractions are sensitive to the scalar density （Kπ｜sq｜0））. Furthermore, the resonant contributions are dominated by the scalar K;（1430）. We hope that these branching fractions could be measured individually in the experiments so as to test the factorization approach and the flavor S U（3） asymmetry. Moreover, the direct CP asymmetries of these decays are also investigated, which could be measured in the running LHCb experiment and Super-b factory in the future.

Influence of ring-down cavity parameters on intensity transmission property in trace gas concentration measurement

In this paper, we describe the basic principles and system design of continuous wave cavity ring-down spectroscopy （CWCRDS）. We also particularly study the nature and the behavior of a novel method to detune a laser and apply it to a cavity ring-down spectroscopy experiment. Both simulations and experiments are completed on the relation between the transmission characteristic and different refiectivities, as well as scanning speed. Output electric field equation is deduced. It has been investigated that how photons are coupled to the cavity and how to accumulate the intensity and leak out of the cavity as a function of time. It is noted that both accumulation of intensity and decay times decrease, and the oscillation amplitude increases as the reflectivity increases. Relative intensity increases with decreasing scanning velocity. Additionally, the simulations show that a non-detuned cavity displays the transmitted signals which are highly dependent on the mirror reflectivity and piezoelectric translator （PZT） modulation speed. Simulations also display that the laser switching off is different from dettming.