Self-reactive rating of thermal runaway hazards on 18650 lithium-ion batteries

Vent sizing package 2 (VSP2) was used to measure the thermal hazard and runaway characteristics of 18650 lithium-ion batteries, which were manufactured by Sanyo Electric Co., Ltd. Runaway reaction behaviors of these batteries were obtained: 50% state of charge (SOC), and 100% SOC. The tests evaluated the thermal hazard characteristics, such as initial exothermic temperature (T ₀), self-heating rate (dT?dt ^?1), pressure-rise rate (dP?dt ^?1), pressure temperature profiles, maximum temperature, and pressure which were observed by adiabatic calorimetric methodology via VSP2 using customized test cells. The safety assessment of lithium-ion cells proved to be an important subject. The maximum self-heating rate (dT?dt ^?1)_max and the largest pressure-rise rate (dP?dt ^?1)_max of Sanyo 18650 lithium-ion battery of 100% SOC were measured to be 37,468.8???C?min^?1 and 10,845.6?psi?min^?1, respectively, and the maximum temperature was 733.1???C. Therefore, a runaway reaction is extremely serious when a lithium-ion battery is exothermic at 100% SOC. This result also demonstrated that the thermal VSP2 is an alternative method of thermal hazard assessment for battery safety research. Finally, self-reactive ratings on thermal hazards of 18650 lithium-ion batteries were studied and elucidated to a deeper extent.     

Nanoseeding via dual surface modification of alkyl monolayer for site-controlled electroless metallization

In this work, an attempt to fabricate nanostructured metallization patterns on SiO(2) dielectric layers is made by using plasma-patterned self-assembled monolayers (SAMs), in conjunction with a novel aqueous seeding and electroless process. Taking octadecyltrichlorosilane (OTS) as a test material, the authors demonstrate that optimizing the N(2)-H(2) plasma conditions leads to the successive conversion of the topmost aliphatic chains of alkyl SAMs to carboxyl (COOH) and hydroxyl (C-OH) functional groups, which was previously found in alkyl SAMs only by exposure to "oxygen-based" plasma. Further modifying the plasma-exposed (either COOH or C-OH terminated) regions with an aqueous solution (SC-1) creates surface functionalities that are viable for site-controlled metallic seeding (e.g., Co or Ni) with an adsorption selectivity of greater than 1000:1. Neither the combination of costly PdCl(2) and complex additives nor the demerits of the associated aqueous chemistry (e.g., seed agglomeration and seed sparseness) are involved. Therefore, the seed particles are only 3 nm in size. Simultaneously, there are sufficient particle densities previously unattainable for electroless deposition to trigger highly resolved Cu metallization patterns with a film thickness of less than 10 nm. The formation of the seed-adsorbing sites is discussed, based on a plasma-dissociated, water-mediated chemical oxidation route.     

Using near-infrared process analysis to study gas-solid adsorption process as well as its data treatment based on artificial neural network and partial least squares

This paper demonstrates the application of near-infrared (NIR) process analysis to study gas-solid adsorption process non-invasively: its experimental setup, data treatment, and potentials as a convenient tool to investigate the gas-solid adsorption process. The experimental setup includes a differential adsorption bed (DAB) monitored by a NIR spectrometer via an optical fiber probe, which makes it convenient and reliable to construct adsorption mass-transfer models. A chemometrics strategy based on back propagation-artificial neural network (BP-ANN) and partial least squares (PLS) has been developed to treat NIR spectra collected during the adsorption process because of the obvious nonlinearity in concentration prediction. This nonlinear problem results from the great concentration variation of the adsorbate adsorbed by the adsorbent during the whole adsorption process, the extraordinarily low concentration of the adsorbed adsorbate at the beginning of the process, and probably NIR distinction between the adsorbate on the first adsorption layer at the beginning of the process and that on the other layers afterward. With the strategy, NIR spectra are pretreated with PLS for data compression and noise reduction, and then a BP-ANN is built as the nonlinear calibration model. As compared with linear calibration algorithm, our strategy has the higher predication ability for the whole adsorption process, even with less calibration samples. Finally, as an example the kinetics of aniline-silica gel adsorption process has been studied through the experimental setup and chemometrics strategy.     

Relative stability and optical nonlinearity of multiple conformers of 1,1′-substituted ferrocenes

The relative stability and the first and second hyperpolarizabilities of various conformers of four 1,1′-diarylethenylferrocenes have been evaluated at the MP2 computational level. Relative stability on the basis of the minimum polarizability principle is in complete agreement with the conclusion from the minimum energy criterion at the higher computational levels. Since the pi–pi interaction is an attractive force, the conformer with the intramolecular pi–pi interactions belongs to the lowest energy structure and is most likely to be populated. The calculated second hyperpolarizability is in excellent agreement with the experimental data available. There appear two low-energy absorption bands in electronic absorption spectra, where the lower-energy band shifts to the red and is enhanced by molecular distortion. This band is responsible for the largest linear polarizability and second hyperpolarizability of the conformer with inversion symmetry and the magnitude of the latter is dominated by one-photon transition.     

夏秋两季洱海、太湖表层混合层的深度变化特征及其机理分析

湖泊表层混合层深度的变化不仅影响湖泊水生生态系统的演变, 而且影响流域的局地气候、降水量的时空格局等. 基于2008年夏秋两季洱海(高原湖泊)和太湖(平原湖泊)的气象与水温廓线观测资料, 分析探讨了两湖表层混合层深度的变化特征及其机制. 结果表明: 夏季洱海能维持持续的分层现象, 秋季有明显的日分层现象, 而在相应的两季中, 太湖仅可能存在日分层现象; 洱海表层混合层深度较同期太湖更浅; 太湖两季的表层混合层深度变化较洱海频繁, 即太湖水体混合与分层的交替过程对气象条件的响应较洱海更为迅速. 太湖这类浅水湖泊, 水深是抑制其存在稳定、持续分层的关键因素, 在合适的辐射条件下, 可形成日分层现象; 而洱海这类深度的湖泊, 净热量通量是影响其是否存在持续、稳定分层的主要因子. 该研究为进一步探讨湖泊与大气两种湍流运动的耦合机制及水生生态环境演替规律等提供了有力的参考.     

DC dielectrophoresis separation of marine algae and particles in a microfluidic chip

This paper reports a microfluidic method of continuous separation of marine algae and particles by DC dielectrophoresis. The locally non-uniform electric field is generated by an insulating PDMS triangle hurdle fabricated within a PDMS microchannel. Both the particles and algae are subject to negative DEP forces at the hurdle where the gradient of local electric-field strength is the strongest. The DEP force acting on the particle or the algae depends on particles’ or algae’s volume, shape and dielectric properties. Thus the moving particles and algae will be repelled to different streamlines when passing the hurdle. In this way, combined with the electroosmotic flow, continuous separation of algae of two different sizes, and continuous separation of polystyrene particles and algae with similar volume but different shape were achieved. This first demonstration of DC DEP separation of polystyrene particles and algae with similar sizes illustrates the great influence of dielectric properties on particle separation and potentials for sample pretreatment.     

Dynamic multiple criteria decision making in changeable spaces: from habitual domains to innovation dynamics

Human behaviors involve dynamic, evolving, interactive and adaptive processes. Important decision makings usually are dynamic, involving multiple criteria in changeable spaces. This article introduces the behavior mechanism that integrates the findings of neural science, psychology, system science, optimization theory and multiple criteria decision making. It shows how our brain and mind operate and describes our behaviors and decision making as dynamic processes of multiple criteria decision making in changeable spaces. Unless extraordinary events occur or special effort exerted, the dynamic processes will be stabilized in certain domains, known as Habitual Domains. Habitual Domains, which play a vital role in upgrading the quality of our decision making and lives, will be explored. In addition, as important consequential derivatives, concepts of Competence Set Analysis and Innovation Dynamics will also be discussed. Note that these concepts involve transitions between dynamic and static states.     

Synchronizations of rotating pendulums via self-learning terminal sliding-mode control subject to input nonlinearity

In this study, under the presentations of system uncertainties, external disturbances, and input nonlinearity in control, a self-learning terminal sliding-mode control scheme is adopted to control the synchronization and anti-synchronization between two chaotic rotating pendulums with different periods of harmonic parametric excitation. Without known bounds of the unmatched nonlinear dynamics, system uncertainties, and external disturbances, the proposed controller, which is associated with time-varying feedback gains, can achieve the control goals. Meanwhile, the feedback gains are not determined beforehand but are self-learning according to the learning rules. Some sufficient conditions for stable synchronizations are performed in the sense of the Lyapunov stability theorem. Besides, numerical simulations are provided to demonstrate the effectiveness of the present scheme.     

Maximal Coordinator Number of Potassium, Rubidium, Caesium and Francium Ions in Gaseous Water

To understand the molecular and electronic structure of alkali metal ions, we carry out the MP2 calculation and demonstrate that the maximal coordinator numbers for the hydrated K^＋ and Rb^＋ are 8, while those for the hydrated Cs^＋ and Fr^＋ are 10. Furthermore, on the basis of the binding energy, the HOMO-LUMO gap and the electron affinity, the stability of the molecular and electronic structures of M^＋ （H2O）8 （M= K, Rb, Cs, Fr） decreases with the increasing alkali metal atomic number and the stability of the molecular structures of M^＋ （H20）8-10 （M= Cs, Fr） decreases with the increasing cluster size.     

中性三甲胺双聚体的红外-真空紫外光谱研究

Infrared-vacuum ultraviolet (IR-VUV) spectra of neutral trimethylamine dimer were measured in the 2500-3800 cm^-1 region. Quantum chemical calculations were performed to identify the structure of the low-lying isomers and to assign the observed spectral features. The bands at 2975 and 2949 cm^-1 were assigned to the antisymmetric C-H stretching and the band at 2823 cm^-1 to the symmetric C-H stretching, respectively. The 2739 cm^-1 band was due to the CH₃ bending overtone, which disappeared at low IR laser power of 1 mJ/mm². The extra band at 2773 cm^-1 could be due to Fermi resonance behavior of the light isotopologue, these are often close in energy and can strongly mix through cubic terms in the potential function. Experimental and theoretical results indicate the likely coexistence of multiple structures. The peak widths of IR spectra of neutral trimethylamine dimer are not significantly affected by the structural transformation, allowing the stretching modes to be well resolved.