基于VAR模型的人力资本与出口贸易增长的关系分析

运用协整和VAR模型从人力资本角度分析其对我国出口贸易额的动态影响,结果表明:人力资本是出口贸易增长的Granger原因,他们之间存在长期的动态稳定关系。脉冲响应分析揭示人力资本对出口额有稳定持续的正的产出弹性,方差分解显示人力资本对出口的贡献占60%多。因此国家必须加大人力资本投资,增加人力资本存量,发挥其内部和外部效应,起到促进出口健康、持续增长的作用。     

Enhanced liquid spreading due to porosity

A conceptual pore level model (Chem. Eng. Sci. 57 (2002) 3401) of spreading of liquid over internally wet porous particles is applied to explain reported rector level enhancement in wetting of trickle bed reactor (Ind. Eng. Chem. Res. 36 (1997) 5133). It is confirmed that a symbiotic relationship exists between internal and external wetting of porous particles whereby each enhances the other. Further, it is illustrated that liquid spreading in porous solids is driven more by porosity than by contact angle. A major implication of this phenomena is that liquid will spread more on less wettable (but porous) surfaces in comparison to more wettable (but nonporus) surfaces and a reinterpretation of experiments involving spreading of liquid over porous solids is required. On a large scenario, it is hoped that present exercise will be in important step towards explaining the complex reactor level macro phenomena by simple and conceptual pore level micro models.     

有机锡化合物催化剂在有机反应中的应用

有机锡化合物具有独特的催化活性,在聚合、加成、酯化和还原等有机合成反应中广泛应用.本文综述了近十年来有机锡化合物在催化领域里的研究进展.     

PAIDD: a hybrid P2P-based architecture for improving data distribution in social networks

Rapid growth in social networks(SNs)presents a unique scalability challenge for SN operators because of the massive amounts of data distribution among large number of concurrent online users.A request from any user may trigger hundreds of server activities to generate a customized page and which has already become a huge burden.Based on the theoretical model and analytical study considering realistic network scenarios,this article proposes a hybrid P2P-based architecture called PAIDD.PAIDD fulfills effective data distribution primarily through P2P connectivity and social graph among users but with the help of central servers.To increase system efficiency,PAIDD performs optimized content prefetching based on social interactions among users.PAIDD chooses interaction as the criteria because user’s interaction graph is measured to be much smaller than the social graph.Our experiments confirm that PAIDD ensures satisfactory user experience without incurring extensive overhead on clients’network.More importantly,PAIDD can effectively achieve one order of magnitude of load reduction at central servers.     

Effects of oxidation and particle shape on critical volume fractions of silver‐coated copper powders in conductive adhesives for microelectronic applications

The effects of oxidation and particle shape on critical volume fractions of silver‐coated copper powders in conductive adhesives are investigated. Silver‐coated copper powders with spherical and flake‐shaped particles were oxidized at temperatures of 30°C, 175°C and 240°C for two hours and dispersed in an epoxy matrix. As silver‐coated copper powders are oxidized at 30°C and 175°C, the critical volume fractions of the conductive adhesives are slightly affected by oxidation and particle shape at these temperatures. As the oxidation temperature approaches 240°C, the critical volume fractions of the conductive adhesives are strongly affected by oxidation temperature and particle shape, owing to the formation of oxides such as Cu₂O on the surface of silver‐coated copper powder—Cu diffuses from the interior to the surface of silver‐coated copper powder and reacts with the oxygen in the air. Silver‐coated copper powder with flake‐shaped particles shows lower critical volume fractions in conductive adhesives than silver‐coated copper powder with spherically shaped particles. Polym. Eng. Sci. 44:2075–2082, 2004. © 2004 Society of Plastics Engineers.     

(1S,4S)-2-甲基-2,5-二氮杂二环[2.2.1]庚烷的合成

以N—位磺酰化的反—4—羟基—L—脯氨酸为原料,以硼氢化钾与氯化锌还原羧基,以三乙胺和丙酮代替吡啶进行羟基磺酰化和羟基氯代反应,“一锅煮”进行取代环合和去N—磺酰化合成(1S,4S)—2—甲基—2,5—二氮杂二环[2．2．1]庚烷,总收率达53％。该法操作简便,收率高,更有利于工业化生产。     

Explaining similarity for SPARQL queries

World Wide Web - Knowledge graph has gained significant popularity in recent years. As one of the W3C standards, SPARQL has become the de facto standard query language to retrieve the desired data...     

基于生成对抗网络的图像清晰度提升方法

视频监控、军事目标识别以及消费型摄影等众多领域对图像清晰度有很高的要求.近年来,深度神经网络在视觉和定量评估的应用研究中取得较大进展,但是其结果一般缺乏图像纹理的细节,边缘过度平滑,给人一种模糊的视觉体验.本文提出了一种基于生成对抗网络的图像清晰度提升方法.为了更好的传递图像的细节信息,采用改进的残差块和跳跃连接作为生成网络的主体架构,生成器损失函数除了对抗损失,还包括内容损失、感知损失和纹理损失.在DIV2K数据集上的实验表明,该方法在提升图像清晰度方面有较好的视觉体验和定量评估.     

A novel ADRC‑based design for a kind of fexible aerocraft

The paper presents a novel control design, which is based on the idea of active disturbance rejection control (ADRC), for a kind of fexible aerocraft whose controlled variable cannot be measured directly. Since the original frame of ADRC cannot be directly applied, the paper puts forward a new extended state observer (ESO) and the corresponding ADRC law. In order to assign the poles of the closed-loop system to ideal positions such that the vibration can be quickly suppressed, an elastic damping term is added into feedback law. The advantages of the new ESO for efectively estimating both the rigid mode and elastic mode from the measurements are discussed. Moreover, the analysis on the stability, the relative stability and the steady state of the closed-loop system is given. Finally, the efectiveness and robustness of the proposed ADRC are verifed by simulations.     

稻草强化生物膜浮床脱除工业尾水中氮素及COD的效果

工业污水处理厂排放的尾水中总氮含量偏高,容易引起地表水体的富营养化。为了提高尾水中总氮的去除效率,通过模拟稳定塘静态和动态试验,对比了不同稻草添加量(0,0.18,0.54 g/L)强化生物膜浮床脱除工业尾水中总氮(TN)的效果。静态试验结果表明:随着稻草量的增加,TN的去除率显著提高;10 d后,添加0(CK)、0.18 g/L(T1)和0.54 g/L(T2)稻草的尾水中,TN去除率分别为18%,40%,93%。动态试验结果显示,水力停留时间(HRT)为 4 d时,CK、T1和T2的平均TN去除率分别为10%,22%,49%,且3种情况下的进出水COD浓度无显著差异。这主要是由于稻草通过缓慢释放碳源为生物膜中异养反硝化细菌提供可利用的有机物。研究成果可为工业尾水深度处理脱氮技术提供参考。