Simultaneous model selection and parameter estimation for lithium‐ion batteries: A sequential MINLP solution approach

Equivalent circuit model (ECM) is a practical and commonly used tool not only in state of charge (SOC) estimation but also in state of health (SOH) monitoring for lithium‐ion batteries (LIBs). The functional forms of circuit parameters with respect to SOC in ECM are usually empirical determined, which cannot guarantee to obtain a compact and simple model. A systematical solution framework for simultaneous functional form selection and parameter estimation is proposed. A bi‐objective mixed‐integer nonlinear programming (MINLP) model is first constructed. Two solution approaches, namely the explicit and implicit methods, are then developed to balance model accuracy and model complexity. The former explicitly treats the model complexity as a constraint and the latter implicitly embeds the model complexity into the objective as a penalty. Both approaches require sequential solution of the transformed MINLP model and an ideal and nadir ideal solutions‐based criterion is utilized to terminate the solution procedure for determining the optimal functional forms, in which ideal solution and nadir ideal solution represent the best and worst of each objective, respectively. Both explicit and implicit approaches are thoroughly evaluated and compared through experimental pulse current discharge test and hybrid pulse power characterization test of a commercial LIB. The fitting and prediction results illustrate that the proposed methods can effectively construct an optimal ECM with minimum complexity and prescribed precision requirement. It is thus indicated that the proposed MINLP‐based solution framework, which could automatically guide the optimal ECM construction procedure, can be greatly helpful to both SOC estimation and SOH monitoring for LIBs. © 2015 American Institute of Chemical Engineers AIChE J, 62: 78–89, 2016     

PtCu alloy nanotube arrays supported on carbon fiber cloth as flexible anodes for direct methanol fuel cell

The rapid development of flexible and portable electrochemical energy devices has promoted the demand for flexible and lightweight electrocatalysts. Here we report flexible high performance electrocatalysts based on PtCu alloy nanotube arrays on carbon fiber cloth (CFC) (PtCu ANTAs/CFC) for direct methanol fuel cell (DMFC). Compared with Pt NTAs/CFC and commercial Pt/C, the PtCu ANTAs/CFC electrocatalysts exhibit significantly improved electrocatalytic activity and durability. Furthermore, the PtCu ANTAs/CFC electrocatalysts show excellent flexibility and they can keep almost constant electrocatalytic performance under the different distorted states, such as normal, bending and twisting states. The improved performance of the flexible PtCu ANTAs/CFC electrocatalysts can be ascribed to unique ANTAs, synergistic effect between Pt and Cu, and porous structure of CFC. This work shows the significant progress of high‐performance Pt‐based flexible anodes for DMFCs. © 2016 American Institute of Chemical Engineers AIChE J, 62: 975–983, 2016     

Growth of silver nanowires on carbon fiber to produce hybrid/waterborne polyurethane composites with improved electrical properties

One dimensional silver nanowires (AgNWs) were grown on carbon fiber (CF) by a facile polyol method. Fourier transform infrared spectrometer (FTIR), laser Raman spectrometer (Raman), field‐emission scanning electron microscopy (FESEM), X ray diffraction instrument (XRD), energy dispersive spectrometer (EDS), and X‐ray photoelectron spectrometer (XPS) were carried out to reveal the structure, morphology, and formation mechanism of the CF‐AgNWs. It was found that AgNO₃ concentration of 1.5 mM, reaction temperature of 160°C, and reaction time of 120 min were appropriate conditions for growth of AgNWs on CF. Moreover, a mechanism was suggested that the cysteamine on CF acted as nucleation centers for growth of silver nanoparticles and then small sized silver nanoparticles reduced from silver nitrate were grown on CF via the silver bonding to sulfur. Through an Ostwald ripening process, small sized silver nanoparticles were grown into larger particles. With the assistance of polyvinylpyrolidone (PVP), these larger particles were directed to grow in a definite direction to form nanowires. It was found that the resistance of CF‐AgNWs was decreased to 19.5 Ω, compared with that of CF (102.6 Ω) with the same quality. Thus, the CF‐AgNWs was added into waterborne polyurethane (WPU) to improve the electrical and dielectric properties of WPU. Results showed the WPU/CF‐AgNWs composite presented a lower percolation threshold than WPU/CF composite. When the content was 2.5 wt %, the volume resistivity of the WPU/CF‐AgNWs (1.90 × 10⁴ Ω cm^?1) was lower by approximately three orders of magnitude than that of WPU/CF (4.19 × 10⁷ Ω cm^?1). When the content was 2.5 wt %, the dielectric constant and dielectric loss of the WPU/CF‐AgNWs were improved to 15.24 and 0.21, which were 34.5 and 40.8% higher than that of WPU/CF. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43056.     

Electrospinning preparation,characterization, and enhanced photocatalytic activity of an Silicotungstic acid (H4SiW12O40)/poly(vinyl alcohol)/poly(methyl methacrylate) composite nanofiber membrane

Silicotungstic acid (H₄SiW₁₂O₄₀)/poly(vinyl alcohol) (PVA)/poly(methyl methacrylate) (PMMA) composite nanofiber membranes were prepared by an electrospinning technique. A PMMA emulsion was mixed with PVA and H₄SiW₁₂O₄₀ evenly in water (electrospinning solvent). The configuration and elemental composition of the membranes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. The results indicate that H₄SiW₁₂O₄₀ with an intact Keggin structure existed in the composite membrane. The as‐prepared H₄SiW₁₂O₄₀/PVA/PMMA membranes exhibited enhanced photocatalytic efficiency (>84%) in the degradation of methyl orange (MO); it outperformed H₄SiW₁₂O₄₀ powder (4.6%) and the H₄SiW₁₂O₄₀/PVA nanofiber membrane (75.2%) under UV irradiation. More importantly, the H₄SiW₁₂O₄₀/PVA/PMMA membranes could be easily separated from the aqueous MO solution, and the photocatalytic efficiency of the membranes decreased inappreciably after three photocatalytic cycles. This may have been due to the enhanced water tolerance of the membranes and the stability of H₄SiW₁₂O₄₀ in the membranes. The photocatalytic process was driven by the reductive pathway with a much faster degradation rate because of the presence of PVA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43193.     

Molecularly imprinted polymer microspheres derived from pickering emulsions polymerization in determination of di(2‐ethylhexyl) phthalate in bottled water samples

The mono‐dispersed macroporous Molecularly Imprinted microspheres (MIPMs) selective for Diethylhexyl Phthalate (DEHP) were synthesized by Pickering emulsion polymerization. Silica nanoparticles were stabilizers in forming a stable oil‐in‐water emulsion, while the polymeric system was prepared by radical polymerization using methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross‐linker. The results of scanning electron microscopy and nitrogen adsorption desorption measurement indicated that the obtained polymer microspheres had regularly porous structure and narrowly diameter distribution (100 nm), besides the specific surface area (S_BET) was 452 m² g^?1, pore volume was 9.685 cm³ g^?1, and pore diameter was 5.089 nm. The equilibrium adsorption capacity of MIPs was 1.75 mg g^?1 at 298 K. Good selectivity for DEHP in another two kinds of analogies (DBP and DAP) was demonstrated with high selectivity coefficients, respectively 17.753 and 19.450. In the end, DEHP‐MIP was used as packing of solid‐phase extraction to form an sensitive analytical method in extraction and enrichment DEHP in bottled water samples with the limits of detection of 1.7–2.5 μg L^?1.The recoveries at three spiking level (0.05, 0.1, and 1 mg L^?1) were varied between at 97.5 and 103.1% with RSD values below 3.5. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43484.     

超高分子量聚乙烯纤维粘接性的研究

初步研究了拉伸倍率、共混改性、化学试剂表面处理对超高分子量聚乙烯（ＵＨＭＷ－ＰＥ）纤维粘接性和强度的影响。结果表明，用铬酸洗液对ＰＥ纤维进行物理和化学改性，是改善ＵＨＭＷ－ＰＥ纤维／环氧树脂粘接性较为有效的方法。     

The Effect of Minimally Invasive Hematoma Aspiration on the JNK Signal Transduction Pathway after Experimental Intracerebral Hemorrhage in Rats

Objective: To explore the effect of minimally invasive hematoma aspiration (MIHA) on the c-Jun NH₂-terminal kinase (JNK) signal transduction pathway after intracerebral hemorrhage (ICH). Methods: In this experiment, 300 adult male Wistar rats were randomly and averagely divided into sham-operated group, ICH group and MIHA group. In each group, 60 rats were used in the detection of indexes in this experiment, while the other 40 rats were used to replace rats which reached the exclusion criteria (accidental death or operation failure). In ICH group and MIHA group, ICH was induced by injection of 70 µL of autologous arterial blood into rat brain, while only the rats in MIHA group were treated by MIHA 6 h after ICH. Rats in sham-operated group were injected nothing into brains, and they were not treated either, like rats in ICH group. In each group, six rats were randomly selected to observe their Bederson’s scales persistently (6, 24, 48, 72, 96, 120 h after ICH). According to the time they were sacrificed, the remaining rats in each group were divided into 3 subgroups (24, 72, 120 h). The change of brain water content (BWC) was measured by the wet weight to dry weight ratio method. The morphology of neurons in cortex was observed by the hematoxylin–eosin (HE) staining. The expressions of phospho-c-Jun NH₂-terminal kinase (pJNK) and JNK in peri-hematomal brain tissue were determined by the immunohistochemistry (IHC) and Western blotting (WB). Results: At all time points, compared with the ICH groups, the expression of pJNK decreased obviously in MIHA groups (p < 0.05), while their Bederson’s scales and BWC declined, and neuron injury in the cortex was relieved. The expression level of JNK was not altered at different groups. The data obtained by IHC and WB indicated a high-level of consistency, which provided a certain dependability of the test results. Conclusion: The JNK signal transduction pathway could be activated after intracerebral hemorrhage, with the expressions of pJNK increasing. MIHA could relieve the histo-pathological damage of nerve cells, reducing brain edema and neurological deficits, and these neuroprotective effects might be associated with suppression of JNK signal transduction pathway.     

载体对Li-Mn氧化物催化甲烷氧化偶联反应作用

采用浸渍法制备不同金属氧化物载体负载的Li-Mn/MO_x(M=Mg,La,Ti,Si,Zr,Ta)催化剂,对其甲烷氧化偶联反应活性进行评价。结果表明,以TiO_2为载体制备的Li-Mn/TiO_2催化剂具有较高的CH_4转化率和C2烃选择性,C_2烃产率显著提高,金属氧化物TiO_2是Li-Mn复合氧化物的优良催化剂载体。n(Li)∶n(Mn)=1.0∶2.0形成的Li-Mn/TiO_2催化剂具有最高的CH_4转化率和C_2烃选择性,n(C_2H_4)∶n(C_2H_6)的增加有助于提高反应产物中C_2H_4的相对浓度,W元素的添加未能进一步提高Li-Mn/TiO_2催化剂的催化活性。Li-Mn/TiO_2催化剂在n(Li)∶n(Mn)=1.0∶2.0、反应温度775℃、反应压力0.1 MPa、V(CH_4)∶V(O_2)=2.5、空速7 200 m L·(h·g)~(-1)和催化剂用量0.5 g条件下,CH_4转化率达31.9%,C_2选择性达52.7%,表现出最佳催化效果。     

Fe/Al_2O_3催化剂催化氧化兰炭废水

采用浸渍法制备Fe/Al_2O_3催化剂,采用BET、XRD和穆斯堡尔谱等进行结构和性能表征。以自制Fe/Al_2O_3为催化剂,应用催化湿式过氧化氢氧化技术处理COD为6 742 mg·L-1的兰炭废水,通过建立正交实验确定最佳实验条件,结果表明,在p H=4、过氧化氢添加量9.6 m L、反应时间150 min和反应温度80℃条件下,兰炭废水COD去除率达66.30%。对催化氧化后的废水进行GC-MS分析,确定最终氧化产物主要为乙酸。表明自制Fe/Al_2O_3催化剂具有优良的催化效果,并使大分子难降解有机污染物分解为易生化的小分子污染物,甚至被完全分解矿化。     

北方水厂应对南水北调水源水处理设施的升级与改造

南水北调工程是一项特大调水工程,南水北调水源水水质复杂,北方水厂常规水处理设施不能满足其处理要求,南水北调水源水的净化处理问题已格外重要和迫切。文章对南水北调水源水水质进行分析研究,讨论了净水设施升级与改造的新型处理技术,在北方水厂原有工艺基础上,一方面增加预处理工艺和深度处理工艺,采用生物预处理法对污染物进行初步去除,并用臭氧活性炭法氧化降解剩余有机污染物;另一方面将常规沉淀、过滤设施升级改造为高密度沉淀池和翻板滤池,处理设施更加简便、高效。