聚丙烯酰胺类树脂热敏特性的研究：（Ⅲ）水／醇溶性透明←→白浊热可…

本文主要报道了聚Ｎ－丙烯酰基吗啉特殊的感热特性－既能在水中，又能在各种一元醇中显示出透明←→白浊的感热特性及主要影响因素－溶剂及浓度的影响。

Numerical Analysis of Explosion Characteristics of Vent Gas From 18650 LiFePO_(4) Batteries With Different States of Charge

The combustion and explosion characteristics of lithium-ion battery vent gas is a key factor in determining the fire hazard of lithium-ion batteries.Investigating the combustion and explosion hazards of lithium-ion batteries vent gas can provide guidance for rescue and protection in explosion accidents in energy storage stations and new energy vehicles,thereby promoting the application and development of lithium-ion batteries.Based on this understanding and combined with previous research on gas production from lithium-ion batteries,this article conducted a study on the combustion and explosion risks of vent gas from thermal runaway of 18650 LFP batteries with different states of charge(SOCs).The explosion limit of mixed gases affected by carbon dioxide inert gas is calculated through the“elimination”method,and the Chemkin-Pro software is used to numerically simulate the laminar flame speed and adiabatic flame temperature of the battery vent gas.And the concentration of free radicals and sensitivity coefficients of major elementary reactions in the system are analyzed to comprehensively evaluate the combustion explosion hazard of battery vent gas.The study found that the 100%SOC battery has the lowest explosion limit of the vent gas.The inhibitory elementary reaction sensitivity coefficient in the reaction system is lower and the concentration of free radicals is higher.Therefore,it has the maximum laminar flame speed and adiabatic flame temperature.The combustion and explosion hazard of battery vent gas increases with the increase of SOC,and the risk of explosion is the greatest and most harmful when SOC reaches 100%.However,the related hazards decrease to varying degrees with overcharging of the battery.This article provides a feasible method for analyzing the combustion mechanism of vent gas from lithium-ion batteries,revealing the impact of SOC on the hazardousness of battery vent gas.It provides references for the safety of storage and transportation of lithium-ion batteries,safety protection of energy storage stations,and the selection of related fire extinguishing agents.

Experimental study on the effects of climatic characteristics on people's adaptability to thermal environment

In order to find out how the climatic characteristics affect people＇s adaptability to thermal environments,experimental studies in a climate chamber are conducted on the effects of transition seasons（from spring to summer）and the occupants＇ native areas on indoor thermal sensations.Results reveal that people＇s tolerances to cool and warm indoor environments are different in the transition season.When the outdoor temperature is higher,the occupants have a weaker tolerance to a cool indoor environment,but a stronger tolerance to a warm indoor environment.Besides,it is found that the occupants＇ thermal sensations depend on both the climatic characteristics of the season and their native areas.The people from southern China present a greater tolerance to both warm and cool indoor environments than those from northern China.The reason can be explained according to the occupants＇ adaptability to the climatic characteristics and the indoor thermal environments of their native areas in different climate zones.

A Novel Built-in CMOS Temperature Sensor for VLSI Circuits

A novel temperature sensor is developed and presented especially for the purpose of on-line thermal monitoring of VLSI chips.This sensor requires very small silicon area and low power consumption,and the simulation results show that its accuracy is in the order of 0.8℃.The proposed sensor can be easily implemented using regular CMOS process technologies,and can be easily integrated to any VLSI circuits to increase their reliability.

Effects of Y on hot tearing susceptibility of Mg-Zn-Y-Zr alloys

The hot tearing susceptibility of MgZn2.5YxZr0.5 （x=0.5, 1, 2, 4, 6） alloys was evaluated by thermodynamic calculations based on Clyne-Davies model. The microstructure and morphology of hot tearing regions of the alloys were observed by X-ray diffraction and scanning electron microscopy. The solidification temperature and shrinkage stress during the solidification of MgZn2.5YxZr0.5 alloys in the“T”type hot tearing permanent-mold were acquired with the attached computer. The effect factors of hot tearing susceptibility of MgZn2.5YxZr0.5 alloys, such as the solidification temperature interval, the variation of solid fraction in vulnerable region, the residual liquid fraction in the final stage, the type of the second phase of the alloys were discussed based on the above calculation and observation. The results demonstrated that the hot tearing susceptibility in the investigated alloys was found as follows：MgZn2.5Y2Zr0.5＆gt;MgZn2.5Y0.5Zr0.5＆gt;MgZn2.5Y4Zr0.5＆gt;MgZn2.5Y6Zr0.5＆gt;MgZn2.5Y1Zr0.5. The highest hot tearing susceptibility of MgZn2.5Y2Zr0.5 alloy related to the following reasons： the largest freezing range, the biggest changing of the variation of solid fraction in vulnerable region, the least liquid film in the final stage of solidification, the formation of the second phase which worsens the liquid flow and interdendritic feeding after dendrite coherency.

Draft sensation distribution of air jet supply system in large space building in summer

To study the draft sensation distribution of an air jet supply system in a large space building in summer,experiments are conducted in a large laboratory.The temperature,velocity and draft sensation distributions at a nozzle height of 4 m in the occupied zone are obtained.Then,the numerical simulation under the test condition is carried out by the computational fluid dynamics（CFD）method.The calculation results of the indoor vertical temperature and the draft sensation distribution are validated by the test data.Simulations with different nozzle heights are conducted.The satisfactory air supply condition is determined by analyzing the draft sensations and the temperatures in the occupied zone under three conditions.The simulation results show that the optimal draft sensation distribution and the uniform temperature and velocity fields can be obtained at a nozzle height of 5 m.

会运动的植物

很多人心目中的植物，是既没有神经和感觉，更不会跳跃或奔跑的，因而相对于能够自如运动的动物来说，植物似乎是安详的、静止的。然而实际情况却并非如此，不少植物都带有较为明显的“运动”特征，由于这些植物对外界因素的感受力比较敏锐，因而产生了向光性、向重性、向触性、向化性和向水性等向性运动，以及感热性、感夜性、感震性等感性运动。下面，就让我们来见识一些较为典型的“会运动”的植物吧。

植物也会运动

很多人心中，植物既没有神经和感觉，更不会跳跃或奔跑，因而相对于能够自如运动的动物来说，植物似乎是安祥、静止的。然而实际情况却并非如此，所有的植物一生都在生长，也就是说一直都在运动，无非是它们的生命运动十分缓慢，相对于动物来说，就好像是“静物”了。而且，在植物世界中，除了大多数相对静态的植物外，实际上还有不少植物还带有较为明显的“运动”特征，由于这些植物对外界因素的感受力比较敏锐，因而产生了向光性、向重性、向触性、向水性等向性运动，以及感热性、感夜性、感震性等感性运动。

Correlation of ^1H NMR Chemical Shift for Aqueous Solutions by Statistical Associating Fluid Theory Association Model

1H NMR chemical shifts of binary aqueous mixtures of acylamide, alcohol, dimethyl sulphoxide (DMSO), and acetone are correlated by statistical associating fluid theory (SAFT) association model. The comparison between SAPT association model and Wilson equation shows that the former is better for dealing with aqueous solutions. Finally, the specialties of both models are discussed.

Effect of Si,Cu and Fe on mechanical properties of cast semi-solid 206 alloys

The development of a modified 206 alloy whose composition was optimized to minimize hot tearing during semi-solid forming was reported. The effect of varying silicon, copper and iron contents was investigated using a design of experiment (DOE) approach. Semi-solid slurries were prepared using the SEED process and injected into a high pressure die casting press. The hot tearing sensitivity results were reported for different alloy variants. The microstructure evolution during the semi-solid preparation was presented along with actual die cast components. The effects of silicon, copper and iron on mechanical properties in the T7 condition were also analyzed. Beyond the benefit of reducing hot tearing, it is shown that the tensile and fatigue properties remain compatible with the automotive industry requirements.

Comparison of castability,mechanical,and corrosion properties of Mg−Zn−Y−Zr alloys containing LPSO and W phases

The Mg–Zn–Y–Zr alloys with long-period stacking-ordered(LPSO)and W eutectic phases were investigated to develop new magnesium casting alloys.The temperatures for T6 heat treatment were selected based on the hardness and electrical conductivity measurements.The hot tearing susceptibility of the alloys with LPSO phase is lower than that of the alloys with W phase,which is associated with the freezing range of the alloys.However,the investigated alloys displayed the same fluidity.Under T6 conditions,increasing the Y content in the alloys resulted in increased yield strength,whereas other tensile properties were similar for the alloys.The corrosion resistance was higher for the alloys with LPSO phase compared to that of the alloys with W phase.Mg−2.5Zn−3.7Y−0.3Zr(mass fraction,%)alloy with LPSO phase possessed high castability and mechanical properties,with a corrosion rate of 2 mm/year.

Water and heat transport in hilly red soil of southern China:II. Modeling and simulation

Simulation models of heat and water transport have not been rigorously tested for the red soils of southern China. Based on the theory of nonisothermal water-heat coupled transfer, a simulation model, programmed in Visual Basic 6.0, was developed to predict the coupled transfer of water and heat in hilly red soil. A series of soil column experiments for soil water and heat transfer, including soil columns with closed and evaporating top ends, were used to test the simulation model. Results showed that in the closed columns, the temporal and spatial distribution of moisture and heat could be very well predicted by the model, while in the evaporating columns, the simulated soil water contents were somewhat different from the observed ones. In the heat flow equation by Taylor and Lary (1964), the effect of soil water evaporation on the heat flow is not involved, which may be the main reason for the differences between simulated and observed results. The predicted temperatures were not in agreement with the observed one with thermal conductivities calculated by de Vries and Wierenga equations, so that it is suggested that Kh, soil heat conductivity, be multiplied by 8.0 for the first 6.5 h and by 1.2 later on. Sensitivity analysis of soil water and heat coefficients showed that the saturated hydraulic conductivity, KS, and the water diffusivity, D(θ), had great effects on soil water transport; the variation of soil porosity led to the difference of soil thermal properties, and accordingly changed temperature redistribution, which would affect water redistribution.

Hot tearing behaviors and in-situ thermal analysis of Mg-7Zn-xCu-0.6Zr alloys

Thermal analysis was used to investigate the microstructural evolution of Mg-7 Zn-x Cu-0.6 Zr alloys during solidification. The effect of Cu content（0, 1, 2 and 3, mass fraction, %） on the hot tearing behavior of the Mg-7 Zn-x Cu-0.6 Zr alloys was investigated with a constrained rod casting（CRC） apparatus, equipped with a load sensor and a data acquisition system. The thermal analysis results of Mg-7 Zn-x Cu-0.6 Zr alloy revealed that the alloy consisted of two distinct phases： α-Mg and Mg Zn2. Three distinct peaks were observed in the alloys with Cu addition, which were identified as α-Mg, Mg Zn Cu and Mg Zn2. In addition, the reaction temperature of α-Mg decreased and the reaction temperatures of Mg Zn2 and Mg Zn Cu increased as the Cu content increased. The experimental results of hot tearing demonstrated that the addition of Cu significantly reduced the hot tearing susceptibility（HTS） of Mg-7 Zn-x Cu-0.6 Zr alloys due to the higher eutectic temperature and the shorter solidification temperature region.

Synthesis and property of temperature and pH sensitive xanthan–MA/PNIPAAm hydrogels

A novel class of xanthan-maleic anhydride (Xan-MA)/poly(N-isopropylacrylamide) hybrid hydrogels was designed and synthesized by solution polymerization. The xanthan-based precursor (Xan-MA) was prepared by substituting the hydroxyl groups in Xan by MA. This Xan-MA precursor was then polymerized with a known temperature sensitive precursor (N-isopropylacrylamide, NIPAAm) to form hybrid hydrogels with a series range of composition ratio of Xan-MA to NIPAAm precursors. These smart hydrogels were characterized by Fourier transform infrared spectroscopy for structural determination, differential scanning calorimertry for thermal property. And maximum swelling ratio, swelling kinetics and temperature response kinetics were studied. The data obtained clearly show that these smart hydrogels are responsive to the external changes of temperature as well as pH value. The magnitudes of smart and hydrogel properties of these hybrid hydrogels depend on the feed composition ratio of the two precursors. With the increase of the content of Xan-MA the maximum swelling ratio, reswelling ratio and thermo-sensitivities increase, and the feed composition ratio of Xan-MA/NIPAAm increases the maximum swelling ratio augment from 13.88 to 23.21. From XMN0, XMN1, XMN3 to XMN5, the lower critical solution temperatures (LCSTs) are 33.02, 36.15, 40.28 and 41.92 ℃, respectively. By changing the composition ratio of these two precursors, the LCST of the hybrid hydrogels could also be adjusted to be or near the body temperature for the potential applications in bioengineering and biotechnology fields.

Detection and Analysis of High Temperature Sensitivity of TGMS Lines in Rice Using AMMI Model

With the AMMI (additive main effects and multiplicative interaction) analysis model, thedetermination of the sensitivity to temperature among different TGMS (thermo-sensitivegenic male sterile) lines was performed. To assess the genetic differences due to hightemperature stress at the fertility-sensitive stage (10-20d before heading), sevengenotypes (six TGMS lines and the control Pei-Ai64S) were grown from May 4 at sevendifferent stages with 10d intervals. The temperatures at the fertility-sensitive stagesinvolved twelve levels from<20 to>℃ under the regime natural conditions in Hangzhou,China. There was considerable variation in pollen fertility among genotypes in responseto high temperature. Five genotypes identified as TGMS lines as their percentages offertile pollens were lower than or close to that of the control except for the unstableline RTS19 (V6). When the temperatures at the fertility-sensitive stage were at Ⅰ-Ⅳ,Ⅴ-Ⅵ and Ⅶ-Ⅻ, the percentages of fertile pollens varied in the ranges of 46.46-48.49%,19.62-22.79% and 3.49-5.87%, respectively. The critical temperatures of sterility andfertility in the five TGMS lines were 25.1 and 23.0℃, respectively. Considering theamounts and directions of main effect and their IPCA (interaction principal componentsanalysis), we can classify the lines and temperature levels into different groups, anddescribe the characteristics of genotypetemperature interaction, offering the informationand tools for the development and utility of thermo-sensitive male sterile lines.Several TGMS rice lines with their reproductive sensitivity to high temperature that canbe screened using the AMMI model may add valuable germplasm to the breeding program ofhybrid rice.

Processing map and hot working mechanisms of Cu-Ag alloy in hot compression process

For Gu-Ag alloy, an important parameter called workability in the forming process of materials can be evaluated by processing maps yielded from the stress-strain data generated by hot compression tests at temperatures of 700-850 °C and strain rates of 0.01-10 s-1. And at the true strain of 0.15, 0.35 and 0.55, respectively, the responses of strain-rate sensitivity, power dissipation efficiency and instability parameter to temperature and strain rate were studied. Instability maps and power dissipation maps were superimposed to form processing maps, which reveal the determinate regions where individual metallurgical processes occur and the limiting conditions of flow instability regions. Furthermore, the optimal processing parameters for bulk metal working are identified clearly by the processing maps.

Hot tearing susceptibility of Mg-xZn-2Y alloys

Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg?2%Y alloy were studied in aconstrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The experimental results indicate thatthe hot tearing susceptibility (HTS) is affected by the content of Zn. The Zn-free base alloy shows the lowest HTS. The HTS ofMg?xZn?2Y alloys increases with increasing Zn content, reaches the maximum at 1.5% Zn, and then decreases with further Znaddition. The high HTS observed in the alloy with 1.5% Zn is attributed to its high force release rate and large force drop duringsolidification. The hot cracks of casting are initiated and propagate along the dendritic or grain boundaries. The predictions of HTS ofMg?xZn?2Y alloys using ProCAST software are in good agreement with the results obtained by experimental measurements.

Rheological characterization of A201 aluminum alloy

The thermodynamic characterization as well as the rheological characterization of the A201 alloy were conducted.Thermodynamic simulations (CALPHAD method) and calorimetric experiments were performed to determine the solidus and liquidus temperatures, the melting range and the sensitivity of the solid fraction at the thixoforming temperatures.The rheology of aluminium alloy A201 was examined using a high temperature Searle rheometer.The flow behaviour was analyzed with concentric cylinders of graphite to avoid chemical interactions with the liquid or semi-solid aluminium.The rotational body was grooved to prevent a phenomenon called wall slippage.Continuous cooling experiment was used to observe the shear rate effects on the flow behaviour.It can be seen that the viscosity level decreases at higher shear rates.Shear rate jump experiment was carried out to evaluate the steady state flow curve within the analyzed shear rate range from 60 s-1 to 260 s-1.It is found that the power law indexes are-1.35 and-1.49 for 35% and 45% solid fraction, respectively.Finally, some mechanical property data of as-cast and as-thixoformed A201 alloy are included indicating the potential for high strength applications.

A Novel Thermally Coupled Reactive Distillation Column for the Hydrolysis of Methyl Acetate

A different pressure thermally coupled reactive distillation column(DPT-RD) for the hydrolysis of methyl acetate(Me Ac) is developed, and its design and optimization procedures are investigated. The sensitivity analysis is carried out to minimize the energy consumption, which is associated with the total annual cost(TAC). The influence of the proposed DPTRD scheme on energy consumption and economic efficiency are evaluated in comparison with the conventional reactive distillation column(CRD). Both the DPT-RD and CRD are simulated with the Aspen Plus?, and it can be observed that for the DPT-RD the energy consumption and the TAC are reduced, and the thermodynamic efficiency is increased as compared with the CRD process.

A SEASONAL INFLUENZA THEORY AND MATHEMATICAL MODEL INCORPORATING METEOROLOGICAL AND SOCIO-BEHAVIORAL FACTORS

On the basis of a comprehensive literature review and data analysis of global influenza surveillance, a transmission theory based numerical model is developed to understand the causative factors of influenza seasonality and the biodynamical mechanisms of seasonal flu. The model is applied to simulate the seasonality and weekly activity of influenza in different areas across all continents and climate zones around the world. Model solution and the good matches between model output and actual influenza indexes affirm that influenza activity is highly auto-correlative and relies on determinants of a broad spectrum. Internal dynamic resonance; variations of meteorological elements (solar radiation, precipitation and dewpoint); socio-behavioral influences and herd immunity to circulating strains prove to be the critical explanatory factors of the seasonality and weekly activity of influenza. In all climate regions, influenza activity is proportional to the exponential of the number of days with precipitation and to the negative exponential of quarter power of sunny hours. Influenza activity is a negative exponential function of dewpoint in temperate and arctic regions and an exponential function of the absolute deviation of dewpoint from its annual mean in the tropics. Epidemics of seasonal influenza could be deemed as the consequence of the dynamic resonance and interactions of determinants. Early interventions (such as opportune vaccination, prompt social distancing, and maintaining incidence well below a baseline) are key to the control and prevention of seasonal influenza. Moderate amount of sunlight exposure or Vitamin D supplementation during rainy and short-day photoperiod seasons, more outdoor activities, and appropriate indoor dewpoint deserve great attention in influenza prevention. To a considerable degree, the study reveals the mechanism of influenza seasonality, demonstrating a potential for influenza activity projection. The concept and algorithm can be explored for further applications.