客观事实与主观分化:中国中产阶层的主观阶层认同分析

近些年来,中国社会中产阶层崛起并不断发展壮大,社会差别和阶层分化日益凸显。社会分层不仅是一种客观事实,还与个体的主观意识密切相关。本文基于CGSS2010的调查数据研究发现,不同社会阶层成员的自我认同已出现明显分化,教育和收入对主观阶层认同具有重要意义,生活经历是建构主观阶层认同的重要变量,但制度分割的影响不具统计意义

Neuronal modeling with intracellular calcium signaling

【中文摘要】 细胞溶质内的游离钙离子在许多细胞活动中发挥着重要的作用。对于神经元,细胞膜上的神经电信号和胞内钙离子化学信号之间有着复杂的相互作用,每个神经元都可看作为一个含有细胞膜和内质网膜的双膜系统,而神经细胞的内质网则可视为神经元内的神经元。本综述探讨了神经元膜上神经电信号与内质网钙通道释放的胞内钙信号相耦合的动力学模型。我们认为,计算神经动力学的一个研究方向是考虑包含胞内钙动力学的神经元模拟,而且该研究前沿转向考虑胞内钙波扩散运动的空间神经元模型。包含内质网钙动力学的神经模型,尤其是考虑胞体和树突内钙扩散的空间神经元模型,将加深我们对神经动力学的认识。 【英文摘要】 Cytosolic Ca2+ ions play an important role in the regulation of numerous aspects of cellular activity in virtually all cell types. There is a complex interaction between the neuronal electrical signals on plasma membrane and the chemical signals of intracellular calcium. Each neuron can be considered as a binary membrane system with plasma membrane and endoplasmic reticulum membrane, and the neuronal endoplasmic reticulum can be regarded as a neuron-within-a-neuron. This review explores the simulation model...supported by the National Natural Science Foundation of China (No. 30970970

中美高校毕业生就业指导工作的比较研究

随着我国高等教育的扩招,高等教育由精英教育阶段迈进大众化教育阶段,随着高校毕业生人数剧增,大学生就业难问题凸现,成为社会、高校、学生家庭共同关注的焦点,也成为制约高校发展的瓶颈。在大众教育阶段,如何指导毕业生良性择业,形成正确的就业理念,目前显得尤为重要。本文深入分析美国大学生就业指导工作,与我国大学生指导工作进行对比,积极探索有益的启示,分析两国就业指导的特点与差距,指出了我国大学生就业指导工作发展的方向,为我国大学生就业指导工作开展提供借鉴和参考

苯丙胺对铜绿微囊藻的生物效应研究

研究了不同浓度苯丙胺在不同条件下对铜绿微囊藻的生长及毒性效应。结果表明 ,低浓度苯丙胺在弱碱性条件下促进铜绿微囊藻的生长 ;高浓度的苯丙胺则抑制其生长。苯丙胺对铜绿微囊藻 2 4、48、72、96h的EC50 值分别为 2 4 .52、1 6 .51、1 0 .76、9.60mg/L ,且其毒性随时间的延长而增

水华蓝藻产毒特性的PCR检测法

特异引物对（ＴＯＸ　１Ｐ／１Ｆ；ＴＯＸ　２Ｐ／２Ｆ）用于检测微囊藻毒素合成酶基因ｍｃｙＢ片段在３８种水华蓝藻中的分布情况。结果显示，所有能产生微囊藻毒素的微囊藻都有特异扩增条带，非产毒株则没有。几种常规的毒性检测方法验证了ＰＣＲ方法所获结果的准确性。本研究发展了以全细胞ＰＣＲ法检测ｍｃｙＢ片断，说明全细胞ＰＣＲ检测法适用于不同来源的蓝藻材料。结果证明以ＤＮＡ为基础鉴别产毒和非产毒微囊藻及其他水华蓝藻的方法是可行和实用的

Effects of Hot Filtration on Yield and Quality of Bio-oil from Fast Pyrolysis of Chinese Fir in Fluidized Bed Reactor

在1 kg/H的小型鼓泡流化床热解反应装置中增设一热过滤装置,对杉木快速热解制取生物油进行了研究,考察了热过滤装置对生物油产率和品质的影响。结果表明:热解油(未经热过滤)和过滤油(经过热过滤)的产率随热解温度的升高先上升后下降,并都在475℃时达到最大值,分别为58.1%和50.7%。热过滤装置的引入降低了生物油的产率(下降5%~10%),且热解温度越高,过滤油产率下降越明显。相比于热解油Ⅰ,过滤油Ⅰ的含水率从13.77%增加到15.83%,P H值从2.18上升到2.23,热值由20.47 MJ/kg降低到19.53 MJ/kg,但固体含量、碱金属和碱土金属均有显著下降,总体下降约75%,减少了生物油中自聚反应的发生。在老化实验过程中,过滤油Ⅰ的含水率、黏度分别增加了10.2%和57.6%,但较热解油Ⅰ变化幅度小;通过gC-MS分析其组成变化,发现过滤油Ⅰ中各组分含量变化幅度较热解油Ⅰ小,表明热过滤使其中不利反应的发生得到了抑制,稳定性较好,显示出热过滤装置对生物油品质提升的良好促进作用,有利于生物油的储存、运输和使用。A hot filter was added to a 1 kg / h bench-scale continuous bubbling fluidized bed system for the fast pyrolysis of Chinese fir to get bio-oils.The effects of hot filter on the yield and stability of bio-oils were studied.The results indicated that both the yields of pyrolysis oil( without hot filtration) and filtered oil( after hot filtration) increased with the increase of pyrolysis temperature,and decreased after 475 ℃,at which the maximum yields were 58.1% and 50.7%,respectively.The addition of hot filter resulted in lower oil yield( approximate 5%- 10% decrease),which became worse when pyrolysis temperature increased.Compared to the pyrolysis-oil Ⅰ,the water content of filtered-oil Ⅰ increased from 13.77% to 15.83%,p H value increased from2.18 to 2.23,and high-heating value decreased from 20.47 MJ / kg to 19.53 MJ / kg.However,it also showed significant reduction in solids contents,alkali and alkaline earth metals,and the overall decline was about 75%,which suppressed the happening of self-polymerization in bio-oils.During the aging tests,water content and kinematic viscosity of filtered-oil Ⅰ increased by 10.2%and 57.6%,but the fluctuation was less than that of pyrolysis-oil Ⅰ.GC / MS analysis of the bio-oils showed that less fluctuation in composition was observed in the filtered-oil Ⅰ.This indicated a positive impact of the hot filter on the quality of bio-oil.国家“973”资助项目子课题(2012CB215306

海域基准价格评估:厦门案例研究

近年来,随着国家资源管理体制改革的加快,海域资源市场化配置程度不断提高,海域招拍挂即将成为海域使用权出让的主要方式。对海域基准价格进行研究,可以科学确定海域使用权的价格,为海域资源市场化配置提供科学支撑。本文建立了海域定级和海域基准价格评估方法,并利用建立的方法评估了厦门市货运港口用海、客运港口用海、游乐场用海和游艇泊位用海的海域基准价格。结果显示,厦门市各级各类海域基准价格差异很大,各地区各类用海的海域基准价格在11.04～89.32万元/公顷之间。从区域看,同一区域不同用海类型的海域基准价格相差很大,厦门岛周边海域基准价格普遍较高,与陆域的经济发展水平相对一致;从用途看,同级别海域游艇泊位用海年均海域基准价格最高,货运港口用海最低

厦漳跨海大桥箱梁海工高性能混凝土的配制和性能研究

针对厦漳跨海大桥引桥箱梁混凝土体积大、环境条件恶劣的特点,开展了以温度控制、耐久性控制以及提高早期强度为目标的跨海大桥箱梁海工高性能混凝土配制技术研究。采用粉煤灰与矿粉双掺技术和混凝土配合比的优化设计,提高混凝土材料自身变形能力和抗裂性能,配制出低水化热、早期强度高、抗氯离子渗透性和抗裂性能良好的跨海大桥箱梁海工高性能混凝土。国家自然科学基金(21073151)资助项

Plenty is Plague: Fine-Grained Learning for Visual Question Answering

纪荣嵘教授团队的论文提出了一种基于强化学习的细粒度学习策略FG-A1C，旨在通过分析视觉问答任务中的样本多样性及标签的冗余性问题来针对性地挑选训练样本以提高模型的训练效率及减少标记支出。 该论文由厦门大学媒体分析与计算实验室的周奕毅博士后助理研究员、纪荣嵘教授（通信作者）、孙晓帅副教授、苏劲松副教授，以及西安交通大学孟德宇教授、清华大学高跃副教授和澳大利亚阿德莱德大学沈春华教授等合作完成。Visual Question Answering (VQA) has attracted extensive research focus recently. Along with the ever-increasing data scale and model complexity, the enormous training cost has become an emerging challenge for VQA. In this paper, we show such a massive training cost is indeed plague. In contrast, a fine-grained design of the learning paradigm can be extremely beneficial in terms of both training efficiency and model accuracy. In particular, we argue that there exist two essential and unexplored issues in the existing VQA training paradigm that randomly samples data in each epoch, namely, the "difficulty diversity" and the "label redundancy". Concretely, "difficulty diversity" refers to the varying difficulty levels of different question types, while "label redundancy" refers to the redundant and noisy labels contained in individual question type. To tackle these two issues, in this paper we propose a fine-grained VQA learning paradigm with an actor-critic based learning agent, termed FG-A1C. Instead of using all training data from scratch, FG-A1C includes a learning agent that adaptively and intelligently schedules the most difficult question types in each training epoch. Subsequently, two curriculum learning based schemes are further designed to identify the most useful data to be learned within each inidividual question type. We conduct extensive experiments on the VQA2.0 and VQA-CP v2 datasets, which demonstrate the significant benefits of our approach. For instance, on VQA-CP v2, with less than 75% of the training data, our learning paradigms can help the model achieves better performance than using the whole dataset. Meanwhile, we also shows the effectivenesss of our method in guiding data labeling. Finally, the proposed paradigm can be seamlessly integrated with any cutting-edge VQA models, without modifying their structures.This work is supported by the National Key R&D Program (No.2017YFC0113000, and No.2016YFB1001503), Nature Sci- ence Foundation of China (No.U1705262, No.61772443, and No.61572410), Post Doctoral Innovative Talent Support Pro-gram under Grant BX201600094, China Post-Doctoral Sci- ence Foundation under Grant 2017M612134, Scientific Re-search Project of National Language Committee of China (Grant No. YB135-49), and Nature Science Foundation of Fu-jian Province, China (No. 2017J01125 and No. 2018J01106). 本项研究得到了厦门大学“人工智能分析引擎”双一流重大专项的支持、国家重点研发专项和国家自然科学基金海峡基金等项目的支持

Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Chiral Carbonyl Iron Systems

手性羰基铁络合物很少被用于芳香酮的不对称氢转移氢化 .利用不同的羰基铁络合物与手性双胺双膦配体现场络合 ,形成手性胺膦铁催化体系 .考察了它们对多种芳香酮的不对称氢转移催化氢化性能 .结果表明 ,三核的手性胺膦铁簇合物是催化芳香酮不对称氢转移氢化的较好体系 .当用三核的铁簇合物 [Et3 NH] + [HFe3 (CO) 11] -体系催化 1,1 二苯基丙酮的氢化时 ,最高可获得 98%的对映选择性 .通过现场红外光谱测定 ,揣测羰基铁簇合物Fe3 (CO) 12 在催化反应过程中保持三核的簇合物的簇骼不变 .Chiral carbonyl iron systems have seldom been used in asymmetric transfer hydrogenation of aromatic ketones. In this study, new chiral iron catalytic systems were synthesized in situ from different carbonyl iron complexes with chiral diaminodiphosphine ligands, respectively. These catalytic systems have been used for the asymmetric transfer hydrogenation of various aromatic ketones under mild conditions. The results indicated that trinuclear iron complexes were the best systems for the reactions. When the [Et 3NH]+[HFe 3(CO) 11]- as catalyst was used for asymmetric reduction of 1,1-diphenylacetone, high enantioselectivity up to 98% was achieved. Monitoring the reaction in situ by infrared spectroscopy, it could be conjectured that the carbonyl iron cluster Fe 3(CO) 12 kept its trinuclear skeleton unchanged during the catalytic reaction.国家自然科学基金 (No.2 0 3730 56);; 福建省科技厅重大科技项目 (No.2 0 0 2F0 1 6);; 福建省厦门市科技局重大科技项目 (No .350 2Z2 0 0 2 1 0 4 4 )资