Electrochemical measurements were conducted to study the electrochemical behavior of gold （Au） and its commonly associated minerals in alkaline thiourea solutions. The results indicated that without addition of any ...Electrochemical measurements were conducted to study the electrochemical behavior of gold （Au） and its commonly associated minerals in alkaline thiourea solutions. The results indicated that without addition of any stabilizer, selective dissolution of Au from stibnite and pyrite was only possible at relatively low thiourea concentrations. As Na2SiO3 was added, pyrite started to become active and an oxida- tion peak appeared; the oxidation peaks of axsenopyrite and chalcocite appeared earlier thaxl that of Au. The chalcocite peak shifted in the positive direction and the peak current increased. Stibnite did not show an oxidation peak and its current was nearly zero. Adding Na2SiO3 favored the selective dissolution of Au when its minerals were associated with chalcocite and stibinte. At pH 12, the Au anode dissolution peak current increased with stabilizer concentration. At 0.38 and 0.42 V and for Na2SiO3 concentration below 0.09 M, the current density continuously increased with Na2SiO3 concentration. The Na2SiO3 concentration had to be adequate to stabilize thiourea. When the potential was higher than 0.42 V, the surface of the Au electrode started to passivate. With an additional increase in potential, the presence of Na2SiO3 could not stop the inevitable decomposition of thiourea.展开更多
Solid electrolyte(SE)is the most crucial factor to fabricate safe and high-performance all-solid-state lithium-ion batteries.However,the most commonly reported SE,including solid polymer electrolyte(SPE)and inorganic ...Solid electrolyte(SE)is the most crucial factor to fabricate safe and high-performance all-solid-state lithium-ion batteries.However,the most commonly reported SE,including solid polymer electrolyte(SPE)and inorganic oxides and sulfides,suffer problems of low ionic conductivity at room temperature for SPE and large interfacial impedance with electrodes for inorganic electrolytes.Here we for the first time demonstrate a novel ionic plastic crystal lithium salt solid electrolyte(OLiSSE)fast ion-conductor dilithium(1,3-diethyl-4,5-dicarboxylate)imidazole bromide with ordered Li-ion conductive nanopathways and an exceptional ionic conductivity of 4.4×10^(−3)Scm^(−1)at 30℃.The prepared OLiSSE exhibits apparent characters of typical ionic plastic crystals in the temperature range of−20 to 70℃,and shows remarkable thermal stability and electrochemical stability below 150℃ and 4.7 V,respectively.No lithium dendrite or short circuit behavior is detected for the Li|OLiSSE|Li cell after the galvanostatic charge-discharge test for 500 h.The fabricated Li|OLiSSE|LiFePO_(4) all-solid-state cell without using any separator and liquid plasticizer directly delivers an initial discharge capacity of 151.4 mAh g^(−1) at the discharge rate of 0.1 C,and shows excellent charge-discharge cycle stability,implying large potential application in the next generation of safe and flexible all-solid-state lithium batteries.展开更多
A novel Frequency Shift Keying (FSK) transmitter that can operate at 40Gb/s and above is proposed. The transmission characteristics of a FSK signal at 40Gb/s are investigated under varying dispersion management. The r...A novel Frequency Shift Keying (FSK) transmitter that can operate at 40Gb/s and above is proposed. The transmission characteristics of a FSK signal at 40Gb/s are investigated under varying dispersion management. The resilience of compensation ratio and power level is obtained. We also experimentally demonstrate transmission over 100km SMF and transparent wavelength conversion based on a semiconductor optical amplifier.展开更多
The development of flame retardant or nonflammable electrolytes is the key to improve the safety of lithium batteries,owing to inflammable organic solvents and polymer matrix in common liquid and polymer electrolytes ...The development of flame retardant or nonflammable electrolytes is the key to improve the safety of lithium batteries,owing to inflammable organic solvents and polymer matrix in common liquid and polymer electrolytes regarded as the main cause of battery fire.Herein,a series of solid-state polyphosphate oligomers(SPPO)as a three-in-one electrolyte that integrated the roles of lithium salt,dissociation matrix,and flame retardant were synthesized.The well-designed SPPO electrolytes showed an optimal ionic conductivity of 5.5×10^(-4)S cm-1at 30℃,an acceptable electrochemical window up to 4.0 V vs.Li/Li+,and lithium ion transference number of 0.547.Stable Li-ion stripping/plating behavior for 500 h of charge-discharge cycles without internal short-circuit in a Li|SPPO|Li cell was confirmed,together with outstanding interface compatibility between the SPPO electrolyte and lithium foil.The optimal Li|SPPO|LiFePO4cell presented good reversible discharge capacity of 149.4 mA h g-1at 0.1 C and Coulombic efficiency of 96.4%after 120 cycles.More importantly,the prepared SPPO cannot be ignited by the lighter fire and show a limited-oxygen-index value as high as 35.5%,indicating splendid nonflammable nature.The SPPO could be a promising candidate as a three-in-one solid-state electrolyte for the improved safety of rechargeable lithium batteries.展开更多
随着生物技术爆发式发展,治疗疾病的药物不再局限于传统的化学药物、中药、天然药物以及蛋白多肽药物。细胞治疗和基因治疗使得细胞、核酸以及病毒有了产品化的需求,成为新兴的“药物”。这类新兴治疗产品(advanced therapy medical pro...随着生物技术爆发式发展,治疗疾病的药物不再局限于传统的化学药物、中药、天然药物以及蛋白多肽药物。细胞治疗和基因治疗使得细胞、核酸以及病毒有了产品化的需求,成为新兴的“药物”。这类新兴治疗产品(advanced therapy medical products,ATMP)与传统生物技术药物不同,它们往往诞生于前沿的科学研究,工业化生产线还不成熟,同时缺少精准的定义和分类方式。这类产品的复杂性为现有药品生产质量管理规范以及药品管理法规带来新的挑战。也为药品生产企业进行新药临床试验申请(investigational new drug application,IND)提出了更多要求。展开更多
无刷直流电机(Brushless DC Motor,BLDCM)控制系统一般采用脉宽调制技术(Pulse Width Modulation,PWM)进行速度调节,导致电流并非理想的方波,产生的电磁转矩也非恒转矩;采用不同PWM方式下的电磁转矩也不同,通过公式推导研究了六种常见的...无刷直流电机(Brushless DC Motor,BLDCM)控制系统一般采用脉宽调制技术(Pulse Width Modulation,PWM)进行速度调节,导致电流并非理想的方波,产生的电磁转矩也非恒转矩;采用不同PWM方式下的电磁转矩也不同,通过公式推导研究了六种常见的PWM方式对无刷直流电机的电磁转矩的影响,分析了不同PWM方式下无刷直流电机电磁转矩大小、换相转矩脉动的情况,论述了不同PWM方式的优缺点,给出了最优换相方法,并通过仿真进行了验证。展开更多
基金financial support from the National Natural Science Foundation of China(No.51504031)the innovation fund of the General Research Institute for Nonferrous Metals(No.53319)
文摘Electrochemical measurements were conducted to study the electrochemical behavior of gold （Au） and its commonly associated minerals in alkaline thiourea solutions. The results indicated that without addition of any stabilizer, selective dissolution of Au from stibnite and pyrite was only possible at relatively low thiourea concentrations. As Na2SiO3 was added, pyrite started to become active and an oxida- tion peak appeared; the oxidation peaks of axsenopyrite and chalcocite appeared earlier thaxl that of Au. The chalcocite peak shifted in the positive direction and the peak current increased. Stibnite did not show an oxidation peak and its current was nearly zero. Adding Na2SiO3 favored the selective dissolution of Au when its minerals were associated with chalcocite and stibinte. At pH 12, the Au anode dissolution peak current increased with stabilizer concentration. At 0.38 and 0.42 V and for Na2SiO3 concentration below 0.09 M, the current density continuously increased with Na2SiO3 concentration. The Na2SiO3 concentration had to be adequate to stabilize thiourea. When the potential was higher than 0.42 V, the surface of the Au electrode started to passivate. With an additional increase in potential, the presence of Na2SiO3 could not stop the inevitable decomposition of thiourea.
基金the financial support of the National Natural Science Foundation of China(21961044,22160901)the Yunnan University’s Research Innovation Fund for graduate students(2020220)。
文摘Solid electrolyte(SE)is the most crucial factor to fabricate safe and high-performance all-solid-state lithium-ion batteries.However,the most commonly reported SE,including solid polymer electrolyte(SPE)and inorganic oxides and sulfides,suffer problems of low ionic conductivity at room temperature for SPE and large interfacial impedance with electrodes for inorganic electrolytes.Here we for the first time demonstrate a novel ionic plastic crystal lithium salt solid electrolyte(OLiSSE)fast ion-conductor dilithium(1,3-diethyl-4,5-dicarboxylate)imidazole bromide with ordered Li-ion conductive nanopathways and an exceptional ionic conductivity of 4.4×10^(−3)Scm^(−1)at 30℃.The prepared OLiSSE exhibits apparent characters of typical ionic plastic crystals in the temperature range of−20 to 70℃,and shows remarkable thermal stability and electrochemical stability below 150℃ and 4.7 V,respectively.No lithium dendrite or short circuit behavior is detected for the Li|OLiSSE|Li cell after the galvanostatic charge-discharge test for 500 h.The fabricated Li|OLiSSE|LiFePO_(4) all-solid-state cell without using any separator and liquid plasticizer directly delivers an initial discharge capacity of 151.4 mAh g^(−1) at the discharge rate of 0.1 C,and shows excellent charge-discharge cycle stability,implying large potential application in the next generation of safe and flexible all-solid-state lithium batteries.
基金supported by National Basic Research Program of China (No. 2010CB328300)National Natural Science Foundation of China (No. 600837004, No. 60777010)+3 种基金Hi-Tech Research and Development Program of China (No. 2009AA01Z253)Pujiang fundHi-Tech Research and Development Program of China (No. 2007AA01Z260)Open Fund of Key Laboratory of Optical Communication and Lightwave Technologies
文摘A novel Frequency Shift Keying (FSK) transmitter that can operate at 40Gb/s and above is proposed. The transmission characteristics of a FSK signal at 40Gb/s are investigated under varying dispersion management. The resilience of compensation ratio and power level is obtained. We also experimentally demonstrate transmission over 100km SMF and transparent wavelength conversion based on a semiconductor optical amplifier.
基金the financial support of the National Natural Science Foundation of China(21961044,22169024)the Yunnan Fundamental Research Projects(202105AC160072,202101BC070001-019,202101AT070280,202102AB080017)the Yunnan University’s Research Innovation Fund for graduate students(2021Y394)。
文摘The development of flame retardant or nonflammable electrolytes is the key to improve the safety of lithium batteries,owing to inflammable organic solvents and polymer matrix in common liquid and polymer electrolytes regarded as the main cause of battery fire.Herein,a series of solid-state polyphosphate oligomers(SPPO)as a three-in-one electrolyte that integrated the roles of lithium salt,dissociation matrix,and flame retardant were synthesized.The well-designed SPPO electrolytes showed an optimal ionic conductivity of 5.5×10^(-4)S cm-1at 30℃,an acceptable electrochemical window up to 4.0 V vs.Li/Li+,and lithium ion transference number of 0.547.Stable Li-ion stripping/plating behavior for 500 h of charge-discharge cycles without internal short-circuit in a Li|SPPO|Li cell was confirmed,together with outstanding interface compatibility between the SPPO electrolyte and lithium foil.The optimal Li|SPPO|LiFePO4cell presented good reversible discharge capacity of 149.4 mA h g-1at 0.1 C and Coulombic efficiency of 96.4%after 120 cycles.More importantly,the prepared SPPO cannot be ignited by the lighter fire and show a limited-oxygen-index value as high as 35.5%,indicating splendid nonflammable nature.The SPPO could be a promising candidate as a three-in-one solid-state electrolyte for the improved safety of rechargeable lithium batteries.
文摘随着生物技术爆发式发展,治疗疾病的药物不再局限于传统的化学药物、中药、天然药物以及蛋白多肽药物。细胞治疗和基因治疗使得细胞、核酸以及病毒有了产品化的需求,成为新兴的“药物”。这类新兴治疗产品(advanced therapy medical products,ATMP)与传统生物技术药物不同,它们往往诞生于前沿的科学研究,工业化生产线还不成熟,同时缺少精准的定义和分类方式。这类产品的复杂性为现有药品生产质量管理规范以及药品管理法规带来新的挑战。也为药品生产企业进行新药临床试验申请(investigational new drug application,IND)提出了更多要求。
文摘无刷直流电机(Brushless DC Motor,BLDCM)控制系统一般采用脉宽调制技术(Pulse Width Modulation,PWM)进行速度调节,导致电流并非理想的方波,产生的电磁转矩也非恒转矩;采用不同PWM方式下的电磁转矩也不同,通过公式推导研究了六种常见的PWM方式对无刷直流电机的电磁转矩的影响,分析了不同PWM方式下无刷直流电机电磁转矩大小、换相转矩脉动的情况,论述了不同PWM方式的优缺点,给出了最优换相方法,并通过仿真进行了验证。
