As a cathode material for thermal batteries,NiS_(2)has a high theoretical capacity but low thermal stability.Besides,the poor formability of NiS_(2)powders also restricts the cathode performance of thermal batteries.I...As a cathode material for thermal batteries,NiS_(2)has a high theoretical capacity but low thermal stability.Besides,the poor formability of NiS_(2)powders also restricts the cathode performance of thermal batteries.In this paper,the novel NiS_(2)/SiO_(2)composite material was developed by high temperature vulcanization to improve the thermal stability formability of NiS_(2).The good filling and lubrication of spherical SiO_(2)can improve the thermal conductivity of NiS_(2)electrode.The discharge test shows that the NiS_(2)/SiO_(2)cathode has a stable discharge voltage at a current density of 200 mA/cm^(2),and the activation time is shortened by nearly 20%compared with the NiS_(2)cathode.In addition,due to the favorable thermal insulation protection of SiO_(2),the initial decomposition temperature of NiS_(2)is increased by 30℃after the addition of SiO_(2).The incorporation of SiO_(2)not only effectively improves the thermal stability and electrochemical properties of NiS_(2),but also improves the cold pressing forming performance of the NiS_(2)powder.Therefore,the novel NiS_(2)/SiO_(2)composite material is more suitable for thermal batteries with high stability and fast response,which is of great significance for improving the maneuverability and quality reliability of weapons and equipment.展开更多
This paper presents a robust model reference adaptive control scheme to deal with un-certain time delay in the dynamical model of a ?uidized bed combustor for sewage sludge. Thetheoretical analysis and simulation resu...This paper presents a robust model reference adaptive control scheme to deal with un-certain time delay in the dynamical model of a ?uidized bed combustor for sewage sludge. Thetheoretical analysis and simulation results show that the proposed scheme can guarantee not onlystability and robustness, but also the adaptive decoupling performance of the system.展开更多
An analytical algorithm was presented for the exact computation of the probability distribution of the project completion time in stochastic networks,where the activity durations are mutually independent and continuou...An analytical algorithm was presented for the exact computation of the probability distribution of the project completion time in stochastic networks,where the activity durations are mutually independent and continuously distributed random variables. Firstly,stochastic activity networks were modeled as continuous-time Markov process with a single absorbing state by the well-know method of supplementary variables and the time changed from the initial state to absorbing state is equal to the project completion time.Then,the Markov process was regarded as a special case of Markov skeleton process.By taking advantage of the backward equations of Markov skeleton processes,a backward algorithm was proposed to compute the probability distribution of the project completion time.Finally,a numerical example was solved to demonstrate the performance of the proposed methodology.The results show that the proposed algorithm is capable of computing the exact distribution function of the project completion time,and the expectation and variance are obtained.展开更多
为有效突破传统时间温度指示器(Time temperature indicator,TTI)温度监测区间单一的问题,实现对猪肉在常温-冷藏-冷冻环境下品质的可视化监测,通过单因素和正交试验调节木糖、甘氨酸、磷酸氢二钾(K_(2)HPO_(4))浓度配比,制备适用于不...为有效突破传统时间温度指示器(Time temperature indicator,TTI)温度监测区间单一的问题,实现对猪肉在常温-冷藏-冷冻环境下品质的可视化监测,通过单因素和正交试验调节木糖、甘氨酸、磷酸氢二钾(K_(2)HPO_(4))浓度配比,制备适用于不同温度区间的时间温度指示器,探究时间温度指示器颜色及吸光度变化规律,利用傅里叶红外光谱和紫外-可见吸收光谱分析TTI内在机理,并构建动力学方程验证恒温和断链情况下TTI与猪肉的匹配度。结果表明,当木糖、甘氨酸、K_(2)HPO_(4)浓度分别为1.00、2.00、1.00 mol/L时TTI颜色变化更为均匀,吸光度更高;随着TTI存储时间的增加,光谱总体变化趋势不大,溶液间相互作用良好;通过阿仑尼乌斯方程得到TTI活化能为79.44 kJ/mol,试验得出猪肉在冷藏或冷冻恒温流通环境下各品质指标的活化能与TTI活化能接近,说明TTI可以很好地监测猪肉品质变化;断链模拟结果显示,猪肉品质变化与TTI颜色变化一致,且在不同温度波动试验下TTI和猪肉各指标之间的等效温度差值均在1.72℃以内,两者货架期终点预测误差为2.3%,表明在温度波动情况下TTI仍然可以很好地监测猪肉品质。展开更多
基金Project(23JCYBJC01870)supported by the Natural Science Foundation of Tianjin,ChinaProject(U22A20119)supported by the National Natural Science Foundation of China。
文摘As a cathode material for thermal batteries,NiS_(2)has a high theoretical capacity but low thermal stability.Besides,the poor formability of NiS_(2)powders also restricts the cathode performance of thermal batteries.In this paper,the novel NiS_(2)/SiO_(2)composite material was developed by high temperature vulcanization to improve the thermal stability formability of NiS_(2).The good filling and lubrication of spherical SiO_(2)can improve the thermal conductivity of NiS_(2)electrode.The discharge test shows that the NiS_(2)/SiO_(2)cathode has a stable discharge voltage at a current density of 200 mA/cm^(2),and the activation time is shortened by nearly 20%compared with the NiS_(2)cathode.In addition,due to the favorable thermal insulation protection of SiO_(2),the initial decomposition temperature of NiS_(2)is increased by 30℃after the addition of SiO_(2).The incorporation of SiO_(2)not only effectively improves the thermal stability and electrochemical properties of NiS_(2),but also improves the cold pressing forming performance of the NiS_(2)powder.Therefore,the novel NiS_(2)/SiO_(2)composite material is more suitable for thermal batteries with high stability and fast response,which is of great significance for improving the maneuverability and quality reliability of weapons and equipment.
基金Supported by National Natural Science Foundation of P.R.China(60374001,60334030)the Chinese Ministry of Education(20030006003)
文摘This paper presents a robust model reference adaptive control scheme to deal with un-certain time delay in the dynamical model of a ?uidized bed combustor for sewage sludge. Thetheoretical analysis and simulation results show that the proposed scheme can guarantee not onlystability and robustness, but also the adaptive decoupling performance of the system.
基金Project(10671212) supported by the National Natural Science Foundation of ChinaProject(20050533036) supported by the Specialized Research Found for the Doctoral Program Foundation of Higher Education of China
文摘An analytical algorithm was presented for the exact computation of the probability distribution of the project completion time in stochastic networks,where the activity durations are mutually independent and continuously distributed random variables. Firstly,stochastic activity networks were modeled as continuous-time Markov process with a single absorbing state by the well-know method of supplementary variables and the time changed from the initial state to absorbing state is equal to the project completion time.Then,the Markov process was regarded as a special case of Markov skeleton process.By taking advantage of the backward equations of Markov skeleton processes,a backward algorithm was proposed to compute the probability distribution of the project completion time.Finally,a numerical example was solved to demonstrate the performance of the proposed methodology.The results show that the proposed algorithm is capable of computing the exact distribution function of the project completion time,and the expectation and variance are obtained.
文摘为有效突破传统时间温度指示器(Time temperature indicator,TTI)温度监测区间单一的问题,实现对猪肉在常温-冷藏-冷冻环境下品质的可视化监测,通过单因素和正交试验调节木糖、甘氨酸、磷酸氢二钾(K_(2)HPO_(4))浓度配比,制备适用于不同温度区间的时间温度指示器,探究时间温度指示器颜色及吸光度变化规律,利用傅里叶红外光谱和紫外-可见吸收光谱分析TTI内在机理,并构建动力学方程验证恒温和断链情况下TTI与猪肉的匹配度。结果表明,当木糖、甘氨酸、K_(2)HPO_(4)浓度分别为1.00、2.00、1.00 mol/L时TTI颜色变化更为均匀,吸光度更高;随着TTI存储时间的增加,光谱总体变化趋势不大,溶液间相互作用良好;通过阿仑尼乌斯方程得到TTI活化能为79.44 kJ/mol,试验得出猪肉在冷藏或冷冻恒温流通环境下各品质指标的活化能与TTI活化能接近,说明TTI可以很好地监测猪肉品质变化;断链模拟结果显示,猪肉品质变化与TTI颜色变化一致,且在不同温度波动试验下TTI和猪肉各指标之间的等效温度差值均在1.72℃以内,两者货架期终点预测误差为2.3%,表明在温度波动情况下TTI仍然可以很好地监测猪肉品质。