实验以废弃小麦秸秆为原料,基于KOH活化-高温烧结法制备了多孔碳材料,采用扫描电子显微镜(SEM)、N_(2)吸附/脱附测试和拉曼光谱(Raman)等测试方法,表征了材料的结构及形貌,并结合恒流充放电(GCD)和循环伏安(CV)测试技术,探究了其在锂离...实验以废弃小麦秸秆为原料,基于KOH活化-高温烧结法制备了多孔碳材料,采用扫描电子显微镜(SEM)、N_(2)吸附/脱附测试和拉曼光谱(Raman)等测试方法,表征了材料的结构及形貌,并结合恒流充放电(GCD)和循环伏安(CV)测试技术,探究了其在锂离子电池中的应用。实验结果表明,采用10 mol·L^(-1)KOH活化的碳材料所制备的电极在循环100次后,依然能具有348.4 m Ah·g^(-1)的比容量,且当电流密度增加到3.5 A·g^(-1)时,其比容量高达431.2 m Ah·g^(-1),表现出较高的倍率性能,这主要是由于材料较多的微孔空隙和较高的无序度,提供了更多的电化学活性点。展开更多
In this paper,we propose a random access scheme termed sign-compute diversity slotted ALOHA(SCDSA).The SCDSA scheme combines diversity transmission with compute-and-forward.Without considering the capture effect and m...In this paper,we propose a random access scheme termed sign-compute diversity slotted ALOHA(SCDSA).The SCDSA scheme combines diversity transmission with compute-and-forward.Without considering the capture effect and multiple user detection techniques,our scheme can reach a high throughput of 0.98 without feedback under finite frame size settings,where the upper bound on performance is 1.Moreover,a lower bound on throughput performance is derived,which is tight in some parameter settings and can be used to approximate theoretical performance.Simulation results validate our analysis and confirm the advantages of our proposed scheme.展开更多
目的通过Meta分析比较耳内镜手术(EES)与耳显微镜手术(MES)治疗中耳胆脂瘤的效果。方法系统检索Embase、Pubmed、Web of Science、Cochrane Library和中国知网五大数据库,限定检索时间为建库至2024年6月30日。纳入比较EES和MES治疗中耳...目的通过Meta分析比较耳内镜手术(EES)与耳显微镜手术(MES)治疗中耳胆脂瘤的效果。方法系统检索Embase、Pubmed、Web of Science、Cochrane Library和中国知网五大数据库,限定检索时间为建库至2024年6月30日。纳入比较EES和MES治疗中耳胆脂瘤的随机对照试验和观察性研究,提取术后复发率、残留率、并发症发生率和术后疼痛发生率等数据,使用Review Manager 5.4统计软件进行Meta分析。结果本研究共纳入19篇文献,涉及1406例患者,其中700例接受EES治疗(EES组),706例接受MES治疗(MES组)。与MES组相比,EES组的术后复发率(OR=0.44,95%CI:0.28~0.70)、术后残留率(OR=0.43,95%CI:0.22~0.84)、术后并发症发生率(OR=0.67,95%CI:0.48~0.93)均显著降低,且术后疼痛发生率(OR=0.11,95%CI:0.05~0.25)较低(均P<0.05)。结论与MES相比,EES可显著降低中耳胆脂瘤患者的术后复发率、残留率及并发症发生率,并可明显降低术后疼痛发生率。展开更多
Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electro...Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.展开更多
文摘实验以废弃小麦秸秆为原料,基于KOH活化-高温烧结法制备了多孔碳材料,采用扫描电子显微镜(SEM)、N_(2)吸附/脱附测试和拉曼光谱(Raman)等测试方法,表征了材料的结构及形貌,并结合恒流充放电(GCD)和循环伏安(CV)测试技术,探究了其在锂离子电池中的应用。实验结果表明,采用10 mol·L^(-1)KOH活化的碳材料所制备的电极在循环100次后,依然能具有348.4 m Ah·g^(-1)的比容量,且当电流密度增加到3.5 A·g^(-1)时,其比容量高达431.2 m Ah·g^(-1),表现出较高的倍率性能,这主要是由于材料较多的微孔空隙和较高的无序度,提供了更多的电化学活性点。
文摘In this paper,we propose a random access scheme termed sign-compute diversity slotted ALOHA(SCDSA).The SCDSA scheme combines diversity transmission with compute-and-forward.Without considering the capture effect and multiple user detection techniques,our scheme can reach a high throughput of 0.98 without feedback under finite frame size settings,where the upper bound on performance is 1.Moreover,a lower bound on throughput performance is derived,which is tight in some parameter settings and can be used to approximate theoretical performance.Simulation results validate our analysis and confirm the advantages of our proposed scheme.
基金the financial support from the National Natural Science Foundation of China(52172110,52472231,52311530113)Shanghai"Science and Technology Innovation Action Plan"intergovernmental international science and technology cooperation project(23520710600)+1 种基金Science and Technology Commission of Shanghai Municipality(22DZ1205600)the Central Guidance on Science and Technology Development Fund of Zhejiang Province(2024ZY01011)。
文摘Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.
