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基于两阶段DEA模型的江苏省动力电池行业回收效率评价研究

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价值工程 2025年第1期44卷 9-11页

作者：张雪晴张晓青江苏师范大学商学院徐州221116

本文选取江苏省2014年至2023年30家动力电池回收企业的实际数据,通过构建DEA模型对这些行业的回收效率进行评价分析。研究结果表明:第一,近十年以来,江苏省动力电池回收行业的回收效率总体处于较低水平,还有很大的提高余地。第二,近十... 详细信息

本文选取江苏省2014年至2023年30家动力电池回收企业的实际数据,通过构建DEA模型对这些行业的回收效率进行评价分析。研究结果表明:第一,近十年以来,江苏省动力电池回收行业的回收效率总体处于较低水平,还有很大的提高余地。第二,近十年以来,江苏省动力电池回收行业的配置效率处于不断提高阶段。

关键词： DEA模型动力电池回收行业回收效率

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Predictive models on photolysis and photoinduced toxicity o persistent organic chemicals

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Frontiers of Environmental Science & Engineering 2013年第6期7卷 803-814页

作者： qing zhang National Natural Science Foundation of China Beijing 100085 China

Photodegradation is a major abiotic transfor- mation pathway of toxic chemicals in the environment, which in some cases might lead to photoinduced toxicities. The data on photodegradation kinetics and photoinduced toxicities of organic chemicals are essential for their risk assessment. However, the relevant data are only available for a limited number of chemicals, due to the difficulty and high cost of experimental determination. Quantitative structure-activity relationship （QSAR） models that relate photodegradation kinetics or photoinduced toxicity of organic chemicals with their physicochemical properties or molecular structural descriptors may enable simple and fast estimation of their photochemical behaviors. This paper reviews the QSAR models on photodegradation quantum yields and rate constants for toxic organic chemicals in different media including liquid phase, gaseous phase, surfaces of plant leaves, and QSAR models on photo- induced toxicity of organic chemicals to plants, bacteria, and aquatic invertebrates. Further prospects for QSAR model development on photodegradation kinetics and photoinduced toxicity of refractory organic chemicals are proposed.

关键词： quantitative structure-activity relationship(QSAR) models photodegradation persistent organicpollutants environmental media mechanisms

Valuation of Stock Loans Under a Markov Chain Model

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Journal of Systems Science & Complexity 2016年第1期29卷 171-186页

作者： PRAGER David zhang qing Department of Mathematics Anderson University Department of Mathematics The University of Georgia

In recent years the use of Markov chain models to model stock price movement has received increased attention among *** chain models combine the discrete movements of a binomial tree model while retaining the Markovian properties of Brownian motion,thus allowing the best properties of both of these *** this paper,the authors consider a Markov chain model in which the underlying market is solely determined by a two-state Markov *** a Markov chain model is strikingly simple and yet appears capable of capturing various market *** proper selection of parameters,the Markov chain model can produce sample paths that are very similar *** very distinct from a classical Brownian motion,as the authors demonstrate in this *** paper studies the stock loan valuation,or the value of a loan in which a risky share of stock is used as collateral,under such a *** programming equations in terms of variational inequalities are used to capture the dynamics of the *** equations are solved in *** optimal solutions are *** examples are also reported to illustrate the results.

关键词： Closed-form solution Markov chain model stock loan

Learning topological defects formation with neural networks in a quantum phase transition

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Communications in Theoretical Physics 2024年第5期76卷 68-76页

作者： Han-qing Shi Hai-qing zhang Center for Gravitational Physics Department of Space ScienceBeihang UniversityBeijing 100191China Peng Huanwu Collaborative Center for Research and Education Beihang UniversityBeijing 100191China

Neural networks possess formidable representational power,rendering them invaluable in solving complex quantum many-body *** they excel at analyzing static solutions,nonequilibrium processes,including critical dynamics during a quantum phase transition,pose a greater challenge for neural *** address this,we utilize neural networks and machine learning algorithms to investigate time evolutions,universal statistics,and correlations of topological defects in a one-dimensional transverse-field quantum Ising ***,our analysis involves computing the energy of the system during a quantum phase transition following a linear quench of the transverse magnetic field *** excitation energies satisfy a power-law relation to the quench rate,indicating a proportional relationship between the excitation energy and the kink ***,we establish a universal power-law relationship between the first three cumulants of the kink numbers and the quench rate,indicating a binomial distribution of the ***,the normalized kink-kink correlations are also investigated and it is found that the numerical values are consistent with the analytic formula.

关键词： neural networks machine learning transverse-field quantum Ising model kibble-zurek mechanism

Relationship　between　global　seismicity　and　solar　activities

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Acta Seismologica Sinica(English Edition) 1998年第4期11卷 495-500页

作者： Gui-qing zhang Beijing Astronomical Observatory Chinese Academy of Science Beijing China

ＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｇｌｏｂａｌｓｅｉｓｍｉｃｉｔｙａｎｄｓｏｌａｒａｃｔｉｖｉｔｉｅｓＧＵＩ－ＱＩＮＧＺＨＡＮＧ（张桂清）ＢｅｉｊｉｎｇＡｓｔｒｏｎｏｍｉｃａｌＯｂｓｅｒｖａｔｏｒｙ，Ｃｈｉｎｅｓ... 详细信息

ＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｇｌｏｂａｌｓｅｉｓｍｉｃｉｔｙａｎｄｓｏｌａｒａｃｔｉｖｉｔｉｅｓＧＵＩ－ＱＩＮＧＺＨＡＮＧ（张桂清）ＢｅｉｊｉｎｇＡｓｔｒｏｎｏｍｉｃａｌＯｂｓｅｒｖａｔｏｒｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅ...

关键词： Solar activity Solar proton events Solar radio flux Sunspot numbers

水肥一体化模式下不同水肥套餐对蜜柚产量、品质及经济效益的影响

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热带作物学报 2025年第1期46卷 123-134页

作者：张青孔庆波栗方亮黄煌伟福建省农业科学院资源环境与土壤肥料研究所福建福州350013 平和县土壤肥料与生态能源站福建漳州363700

通过2020—2022年定位试验,研究水肥一体化条件下不同水肥套餐对蜜柚产量、品质及经济效益等的影响,为探索和实践蜜柚水肥一体化施肥模式提供依据。对平和蜜柚高低产园分别设置4种处理方式:(1)TF(常规施肥)、(2)30%WF(30%水肥套餐)、(3)... 详细信息

通过2020—2022年定位试验,研究水肥一体化条件下不同水肥套餐对蜜柚产量、品质及经济效益等的影响,为探索和实践蜜柚水肥一体化施肥模式提供依据。对平和蜜柚高低产园分别设置4种处理方式:(1)TF(常规施肥)、(2)30%WF(30%水肥套餐)、(3)50%WF(50%水肥套餐)、(4)70%WF(70%水肥套餐)。2020—2022年定位试验结果表明:水溶肥套餐不同程度减量施肥对蜜柚产量影响差异显著,高低产园年平均产量影响均为:70%W>50%WF>TF>30%WF;高产园50%WF、70%WF处理比TF处理年平均增产率分别为12.43%、24.67;低产园50%WF、70%WF处理比TF处理年平均增产率分别为15.05%、26.80%;高、低产园蜜柚年平均产量均以70%WF处理最高(高产园67845.5 kg/hm^(2)、低产园53495.5 kg/hm^(2)),低产园增产幅度大于高产园;高、低产园中年平均次果率均以70%WF效果最佳(高产园5.71%、低产园4.67%)。高、低产园不同水溶肥套餐施肥处理对蜜柚果肉粒化率无显著影响,但对单果重、果肉重影响较为显著;且不同水溶肥套餐施肥处理蜜柚裂果率年际变异大;70%水溶肥套餐施肥明显改善了蜜柚基本农艺性状,提高单果重,降低裂果率。2021、2021年高、低产园中4种处理可溶性固形物、可溶性糖、可滴定酸度增减幅度不大,各处理间差异不显著;70%水溶肥套餐蜜柚各品质指标均为最佳。高产园50%WF、70%WF处理年平均最终净收益较TF处理分别增收30.58%、47.79%。年平均产投比以70%WF处理最高(4.29∶1),较TF处理高1.31倍。低产园50%WF、70%WF处理年平均最终净收益较TF处理分别增收40.41%、59.67%。年平均产投比以70%WF处理最高(3.63∶1),比TF处理高1.17倍;高、低产园中均以70%水溶肥套餐处理经济效益最高,低产园经济效益增幅大于高产园。水肥一体化模式下不同水肥套餐减量施肥具有提高蜜柚产量、经济效益和改善品质等效果,且在高低产园中蜜柚施用70%WF处理对提高蜜柚产量、经济效益和改善品质等效果最好,为最佳施肥处理,推荐应用。

关键词：减量施肥蜜柚质量经济效益水肥一体化

Phase relations and hydrogenation behavior of (La_(1-x)Mg_x)_3Al alloys

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Rare Metals 2007年第1期26卷 8-12页

作者： LIU Yujie zhang qing＇an School of Materials Science and Engineering Anhui University of Technology Ma＇anshan 243002 China

The crystal structures and hydrogenation behavior of （La1-xMgx）3Al （x = 0.1, 0.2, 0.3, and 0.4） alloys were investigated. It was found that the alloys with x = 0.1 and 0.2 consist of La（Mg,Al）, La, and a novel phase. The novel phase was determined as La2Al. It is shown that the amount of La2Al decreases as the Mg content increases. When x increases to 0.3, only La（Mg,Al） and a small amount of La2Al exist. When x is 0.4, La2Al phase disappears and the alloy contains both La（Mg,Al） and La（Al,Mg）2 Laves phase. The （Lao.9MgoA）3Al and （***0.3）3Al alloys can be decomposed into LaH3, MgH2, and La2Al5 by the absorption of hydrogen at 473 K.

关键词： intermetallic compound crystal structure X-ray diffraction hydrogenation characteristic

Effect of Al content on the phase structure and the hydrogenation characteristic of La(Mg_(1-x)Al_x) alloys

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Rare Metals 2006年第6期25卷 654-658页

作者： HOU qingyu zhang qing＇an School of Materials Science and Engineering Anhui University of Technology Ma＇anshan 243002 China

La（Mg1-xAlx）（x=0.2, 0.4, 0.6, 0.8） alloys have been prepared using induction melting followed by annealing. It is found that partial substitution of Mg by Al does not lead to a change in crystal structure, and the alloys have a single LaMg phase when x 〈 0.4. The lattice parameter of the LaMg phase decreases obviously after the partial substitution of Mg by Al. However, further substitution of Mg by Al leads to the coexistence of multiple phases when x ≥ 0.6. The alloys consist of the LaMg, LaAl, LaAl2, and La5Al4 phases. The LaMg phase decreases, whereas the La5Al4 phase increases with the increase in x. The Al-substituted La（Mgo.6Al0.4） alloy can be hydrogenated into the tetragonal LaH3, cubic LaH3, MgH2, and LaPd under 5 MPa at 473 K for 5 d.

关键词： intermetallic compound phase structure hydrogenation characteristic X-ray diffraction

Vertical Diffusion Coefficient with Stratification Effect for Silty Sediment Suspension Under Waves

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China Ocean Engineering 2023年第2期37卷 323-332页

作者： YANG Guang-yao zhang qing-he State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

To analyze previous experimental data of suspended sediment concentration for silty sediment with different sediment particle sizes due to waves, a new stratification correction coefficient is presented. The suspended sediment concentration gradient and sediment particle diameter are selected as parameters. Furthermore, a diffusion coefficient model with a stratification effect over the whole water depth for silty sediment suspension under waves is developed. The comparison between the suspended sediment concentration calculated by the presented model and several groups of experimental data shows that the model can reasonably reflect the vertical distribution of silty sediment *** stratification effect calculated by the present model decreases with an increase in the sediment particle diameter,which indicates that the model can be extended to describe the suspended sediment concentration of fine to medium sand when the near-bottom sediment concentration is not very high. Although the original model needs to be iteratively solved, the approximate method without iteration is recommended for applications when the near bottom sediment concentration is between 10 and 20 kg/m~3 due to the small difference between the non-iterative and iterative solution for near bed layer suspended sediment concentration, which plays a major role in sediment transport.

关键词： stratification silty sediment suspension diffusion coefficient wave