摘要：Hamamatsu R1924A is one of the most widely used photomultiplier tubes(PmTs) in nuclear *** the active base suitable for R1924A is still not available in market, an active base is designed for Hamamatsu R1924A PmT, and the test results at high counting rates are presented. The active bases with two different sets of resistor chains were tested and compared by a frequency-controlled green straw hat LED light. A stable signal output up to 100 kHz is achieved using frequency-controlled LED pulsed light. The temperature of bases, which reflects the power consumption and is crucial for applications in vacuum, is also monitored with the same LED pulsed light. The temperature of the active base with smaller resistances reaches about twice of that of the active base with larger resistances in the resistor chain. For the applications in vacuum, the active base with resistance between the two sets of resistor chains may be preferable.

摘要：Photosynthetic terpene production represents one of the most carbon and energy-efficient routes for converting CO_(2)into *** photosynthetic organisms,metabolic engineering has led to limited success in enhancing terpene productivity,partially due to the low carbon *** this study,we employed systems biology analysis to reveal the strong competition for carbon substrates between primary metabolism(e.g.,sucrose,glycogen,and protein synthesis)and terpene biosynthesis in Synechococcus elongatus PCC *** then engineered key“source”and“sink”***“source”limitation was overcome by knocking out either sucrose or glycogen biosynthesis to significantly enhance limonene production via altered carbon ***,a fusion enzyme complex with geranyl diphosphate synthase(GPPS)and limonene synthase(LS)was designed to further improve pathway kinetics and substrate *** synergy between“source”and“sink”achieved a limonene titer of 21.0 mg/***,the study demonstrates that balancing carbon flux between primary and secondary metabolism can be an effective approach to enhance terpene bioproduction in *** design of“source”and“sink”synergy has significant potential in improving natural product yield in photosynthetic species.

摘要：醇的脱水作为一种重要的烯烃制备方式被广泛应用于实验室与工业生产中。介绍了一个环己醇酸性脱水制备环己烯的新设计。该设计通过利用产物环己烯与水形成低沸点共沸物被蒸馏分离从而促进平衡移动,使得实验操作便捷纯化容易,避免了分水器或脱水剂的使用。该实验设计与流程广泛存在于国外本科生相关课程中,值得国内有机化学实验设计所借鉴。

摘要：This work investigates the machining temperatures of ultra-fine-grained titanium(UFG Ti),prepared by equal channel angular extrusion,through analytical *** Ti has great usefulness in biomedical applications because of its high mechanical strength,sufficient manufacturability,and high *** temperatures were predicted using a physics-based predictive model based on material constitutive relation and mechanics of the orthogonal cutting *** minimization between the stress calculated using Johnson–Cook constitutive model and the same stress calculated using mechanics model yields the estimation of machining temperatures at two deformation *** agreements are observed upon validation to the values reported in the *** machinability of UFG Ti is investigated by comparing its machining temperature to that of Ti–6Al–4V alloy under the same cutting *** lower temperatures are observed in machining UFG *** computational efficiency of the presented model is investigated by comparing its average computational time(~0.5 s)to that of a widely used modified chip formation model(8900 s)with comparable prediction *** work extends the applicability of the presented temperature model to a broader class of materials,specifically ultra-fine-grained *** high computational efficiency allows the in situ temperature prediction and optimization of temperature condition with process parameters planning.

摘要：Gangster films in the Pre-Code Era were historically produced to address social and economic issues during the Great Depression.A particularly controversial gangster film,Scarface:The Shame of the Nation(1932),was produced/directed by Howard Hawks and Howard *** producers/directors created realistic and raw scenes of violence,smuggling,and explosions that were entertaining to the audience but contained a strong,passionate *** Scarface:The Shame of the Nation was wildly popular,films such as the 2013 Gangster Squad,also about organized crime,contained a somewhat different message due to it having been produced in a different *** conveyed a message addressing the issues of society while Gangster Squad’s message was the telling of Italian mobster mickey Cohen’s story for entertainment.

摘要：冰片作为一种自然界广泛存在的次级代谢产物,可以通过樟脑的还原反应制备。但由于冰片极易氧化为樟脑,实验室中常使用硼氢化钠还原樟脑制备冰片的方法。该法可能生成2种冰片异构体,可以通过动力学控制获得其中一个异冰片从而使其成为不可逆反应。该有机化学实验设计在美国与欧洲国家均有涉及,但在国内教材中只是单纯设计为环己酮等单分子的还原反应,缺乏体现化学在解决实际问题中的实用性以及课堂的趣味性。该实验的引进不失为改进国内有机化学实验设计的良好素材。

摘要：古筝独奏曲《长相思》将古曲《春江花月夜》的素材与陕西地方音乐素材融合,基于传统和现代作曲手法结合创作而成。作曲家采用五声音阶调式调性的变化和转换与现代古筝技巧相配合,塑造出"思慕"、"怅惘"、"感慨"、"摧心肝"等意象形态。长摇、单手泛音、快速指序及多声部织体演奏是此四意象表现的重点技术技巧。演奏中,尚需兼顾此四种意象相互联结、平衡,力求凸显全曲"感伤"的情感主题。

摘要：身份标识技术是食品溯源系统中的关键技术之一,有效的身份标识技术应具有唯一性、识别鲁棒性、耐磨损性的特点。针对粮食生产中谷物生产多源头混合配送和分销而难以追溯到源产地的问题,该文提出采用溯源颗粒标识谷物身份信息的方法,以生产工艺参数压力及配方为影响因素,设计了影响基于糖类型和基于纤维素类型2种溯源颗粒的表面粗糙度的正交试验;并应用模糊综合评判方法分析2种溯源颗粒最优工艺参数组合。该研究探索了具有较光滑表面的追溯颗粒生产过程中生产参数的优化策略,为进一步研究谷物溯源颗粒的信息标识及提高生产工艺提供技术支持。

摘要：21世纪是生命科学与信息科学高速发展的时代,化学作为理科的中心学科与此二者均有紧密的联系。伴随着各种交叉学科的诞生与发展,将信息科学技术整合有机化学方法并用于认知生物大分子进而解决生命科学问题也是大势所趋,而在生物化学与化学生物学基础教学中引入相关内容也具有前瞻性与必要性。国外化学本科的基础教育也切合时宜地以一个生物信息学的最常用软件PymOL为例设计相关实验,让学生在了解反应中的有机化学机理的基础上,学习酶的三维结构,并探究酶催化该反应的原因。此设计结合了有机化学、生物化学、生物信息学、蛋白质结构生物学等多学科,可以加深学生对多肽与蛋白质的高级结构的认识,并为今后的生物化学学习与研究打下基础,同时有利于培养学生对于化学的兴趣,可谓一举多得。这对于培养交叉学科人才,做出开创性研究极为重要。对国内生物有机化学实验的设计有借鉴作用。

摘要：全无机钙钛矿纳米晶具有发射光谱窄、发光量子效率高和发光波长可调等优点,在光电子材料和器件领域具有广阔的应用前景.离子掺杂可以调节其原始的晶体结构和发光性能,或者赋予其额外的功能.本文设计了一种基于连续流动反应制备Ce3+掺杂的全无机钙钛矿纳米晶的微流控反应器.流动合成Ce3+掺杂全无机钙钛矿纳米晶的机理是前驱体离子在限域微通道中的有效物理混合、晶种在不良溶剂中的反应成核以及全无机钙钛矿纳米晶沿着流动方向的晶体生长.利用光纤式吸收光谱仪和光纤式荧光光谱仪可以对合成过程进行在线监测.通过改变微流控反应器的流动参数,可以便捷地控制Ce3+的掺杂浓度,最高可达1%.Ce3+掺杂可以提高全无机钙钛矿纳米晶的光致发光效率和稳定性.Ce3+掺杂的CsPbBr3全无机钙钛矿纳米晶可用于制造色纯度高达93.3%的绿色发光二极管,以及色温为10,436 K、CIE色坐标为(0.261,0.317)、显色指数(CRI)为72.1的白色发光二极管.微流控反应器连续可控合成全无机钙钛矿纳米晶为高性能光电材料和器件的应用开辟了新途径.