Fe, N, S-doped porous carbon as oxygen reduction reaction catalyst in acidic medium with high activity and durability synthesized using CaCl2 as template

燃料电池是一种可将化学能通过电催化反应直接转化成电能的装置,具有能量密度高和清洁无污染等优点.燃料电池阴极氧还原反应(ORR)的动力学较迟缓,是; 电池能量效率损失的主要原因.目前ORR催化活性最高的是铂基催化剂,但由于贵金属铂价格昂贵,储量稀少,且对燃料小分子渗透的抗性较差,严重制约了燃料; 电池的大规模应用.因此,高性能、低成本的非贵金属催化剂成为燃料电池领域的研究热点.本文选用含氮量高达45%的三聚氰胺-甲醛树脂为碳源和氮源,Fe; (SCN)_3为铁源和硫源,以CaCl_2为模板,在高温和铁的催化作用下将树脂碳化,经酸洗和二次热处理工艺,制备出铁、氮、硫共掺杂的多孔碳(Fe; NS-PC).干燥后的CaCl_2颗粒可防止树脂在高温下交联形成块状碳颗粒,同时起到造孔模板的作用.CaCl_2颗粒在温和条件下即可除去,无需强; 腐蚀性条件,因此不会对催化活性中心造成破坏.在Fe/N/C催化剂中掺杂S可进一步提高催化活性,不添加碳载体可避免低活性的碳载体降低质量活性,多孔; 结构可促进传质,充分利用活性位点.我们优化了热处理温度,并对催化剂的结构、组分及催化性能等进行了表征分析.结果表明,热处理温度为900; °C时,可将树脂完全转化成多孔碳,并获得较高的杂原子掺杂量,可达到最优活性.CaCl_2为模板剂可避免使用强腐蚀性试剂去除模板,有利于保留活性位; ,并得到多孔结构.FeNS-PC-900的比表面积可达775; m~2/g.得益于原位掺杂的合成工艺,各掺杂元素在多孔碳表面均匀分布.在酸性介质中,FeNS-PC-900的半波电位可达到0.811; V,仅比商业Pt/C催化剂低78 mV;在0.8 V电位下的质量活性为10.2; A/g,表现出优异的催化活性.经过10000圈加速衰减测试后,其半波电位仅下降了20 mV,在0.75 V电位下持续放电10000; s后,其ORR电流仍保持初始电流的84.4%,具有比Pt/C更加优异的稳定性.以FeNS-PC-900为阴极催化剂的质子交换膜燃料电池的最大功率; 密度可达到0.49 W/cm~2,并在0.6 V电压下持续放电10; h后,其电流仍可保持初始电流的65%,表现出良好的应用潜力.FeNS-PC-900具有高掺杂含量、高比表面积和多孔结构,并且杂原子在催化剂表面均; 匀分散,在半电池和燃料电池测试中都表现出优异的催化活性和稳定性,表明其是一种非常有潜力应用于燃料电池的非贵金属氧还原催化剂.Proton exchange membrane fuel cells suffer from the sluggish kinetics of the oxygen reduction reaction (ORR) and the high cost of Pt catalysts. In the present work, a high-performance ORR catalyst based on Fe, N, S-doped porous carbon (FeNS-PC) was synthesized using melamine formaldehyde resin as C and N precursors, Fe(SCN)(3) as Fe and S precursors, and CaCl2 as a template via a two-step heat treatment without a harsh template removal step. The results show that the catalyst treated at 900 degrees C (FeNS-PC-900) had a high surface area of 775 m(2)/g, a high mass activity of 10.2 A/g in an acidic medium, and excellent durability; the half-wave potential decreased by only 20 mV after 10000 potential cycles. The FeNS-PC-900 catalyst was used as the cathode in a proton exchange membrane fuel cell and delivered a peak power density of 0.49 W/cm(2). FeNS-PC-900 therefore has good potential for use in practical applications. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.National Basic Research Program of China [2015CB932303]; National; Natural Science Foundation of China [21373175, 21621091

ULK1/2所构成的信号节点除控制细胞自噬外还控制葡萄糖代谢通路

文章简介在细胞感受到环境中营养物质和生长因子的提供量发生改变后,代谢通路的重编程对于维持此时胞内的稳态是非常重要的过程。ULK1和ULK2是传递外界应激信号至自噬发生的重要整合因子。本项研究发现,在缺少氨基酸和生长因子时,ULK1/2能直接磷酸化多个糖酵解相关的酶,包括己糖激酶(HK)、国家自然科学基金重点项目；国家科技部(973课题)；国家基础科学人才培养基金等的经费支持

Social exchange approaches to promoting inter-organizational citizenship collaborative behaviors in the construction project team

Inter-organizational citizenship collaborative behavior (OCCB) is critical for project team members to share information and integrate resources. However, prior studies found that high OCCBs are absent in project teams. This study aims to explore social exchange approaches to promote project team members’ OCCBs in the construction project team from the social exchange perspective. A questionnaire survey was undertaken online. A two-stage SEM was conducted to verify the measurement and structural models. Confirmatory factor analysis was conducted to verify the measurement model’s reliability and validity, the structural model was assessed by examining the model’s fitness, and path coefficients were used to test the hypotheses. The findings showed that relational social exchange is more effective than contractual social exchange for OCCBs. Meanwhile, contractual control and benevolence trust are verified as mediators between competence trust and OCCB. Three pathways are explored to enhance project team members’ OCCBs: relational social exchange dominated strategy (i.e., dominant competence trust strategy and competence trust-benevolence trust strategy) and relational-contractual hybrid strategy (i.e., competence trust-contractual control strategy). This study expands the social exchange theory in the inter-organizational citizenship collaborative behavior in construction project teams and supports project management by verifying the enabling mechanisms

Epidemiology of benign essential blepharospasm: A nationwide population-based retrospective study in Taiwan.

ImportanceThis study provides a nationwide, population-based data on the incidence of benign essential blepharospasm in Asian adults.BackgroundTo describe the incidence, patient demographics, and risk factors associated with benign essential blepharospasm.DesignPopulation-based retrospective study.Participants and samplesA total of 1325 patients with benign essential blepharospasm were identified.MethodsPatients with diagnosis of blepharopsasm between January 2000 and December 2013 were sampled using the Longitudinal Health Insurance Database 2000. Secondary blepharospasm that may be related to neurological, trauma, and ocular surface disease were excluded.Main outcome measuredMultivariate conditional logistic regression was used to estimate the odds ratios for potential risk factors of benign essential blepharospasm.ResultsThe mean annual incidence was 0.10‰ (0.07‰ for males, and 0.12‰ for females). The peak incidence was in the 50 to 59-year-old age group (0.19‰). People living in urban regions have more risk of developing blepharospasm comparing to people living in less urban regions (p Conclusions and relevanceHigher level of urbanization, white-collar work, sleep disorders, mental health diseases, dry eye-related diseases, Parkinsonism, and rosacea are possible risk factors for benign essential blepharospasm

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