铝合金抽油杆柱深抽的初步研究

机抽井深抽是恢复油井产量行之有效的措施，为解决钢质杆深抽时驴头负荷、曲柄扭矩和杆柱应力过大的问题，我国西部某油田提出了使用铝合金抽油杆的设想。本主根据抽油杆柱设计理论导出了深抽杆柱各级下入深度的公式；对不同工艺参数配合下的计算结果进行了对比分析，对铝合金抽油杆柱用于深抽的可行性进行了初步研究。     

Remaking the labour movement in Italy: the revival of strikes at Fiat-Chrysler Automobiles in 2015–17

ABSTRACT

After the Fiat-Chrysler merger in 2009, CEO Sergio Marchionne imposed a drastic reorganization of labour relations in Italy’s plants, precipitating a profound crisis of the system of industrial relations in the country. But between 2015 and 2017 a significant section of workers at Melfi, Atessa and Termoli plants went on strike against compulsory overtime and labour intensification, establishing links with grassroots unions that successfully organized in logistics. The metalworkers’ union FIOM-CGIL, however, delegitimized the union representatives who resisted Marchionne’s plans. In this article, we trace the context and development of these still little-known strikes. Because of their growing institutionalization, we argue, the confederal unions (CGIL, CISL, UIL) have both failed to mobilize workers and repressed workers’ attempts to resist the deterioration of their conditions. The strikes at FCA and in logistics, however, show that new forms of radical unionism are emerging, pointing to new possibilities for working-class organizing.     

Transition probabilities and ARL performance of Six Sigma zone control charts

In this article, Six Sigma zone control charts (SSZCCs) are proposed for world class organizations. The transition probabilities are obtained using the Markov chain approach. The Average Run Length (ARL) values are then presented. The ARL performance of the proposed SSZCCs and the standard Six Sigma control chart (SSCC) without zones or run rules is studied. The ARL performance of these charts is then compared with those of the other standard zone control charts (ZCCs), the modified ZCC and the traditional Shewhart control chart (SCC) with common run rules. As expected, it is shown that the proposed SSZCC outperforms the standard SSCC without zones or run rules for process shifts of any magnitude. When compared to the other standard ZCCs and the Shewhart chart with common run rules, it is observed that the proposed SSZCCs have much higher false alarm rates for smaller shifts and hence they prevent unwanted process disturbances. The application of the proposed SSZCC is illustrated using a real time example.     

Machine Learning Vasicek Model Calibration with Gaussian Processes

In this article, we calibrate the Vasicek interest rate model under the risk neutral measure by learning the model parameters using Gaussian processes for machine learning regression. The calibration is done by maximizing the likelihood of zero coupon bond log prices, using mean and covariance functions computed analytically, as well as likelihood derivatives with respect to the parameters. The maximization method used is the conjugate gradients. The only prices needed for calibration are zero coupon bond prices and the parameters are directly obtained in the arbitrage free risk neutral measure.     

生产者货币计价决定因素的实证研究

利用12个发达国家和发展中国家的非平衡面板样本数据,对微观、宏观和其他因素对生产者货币计价(PCP)的影响进行实证研究,指出经济规模、市场份额、金融市场的发达程度、币值的对内稳定性和产品差异化程度是最主要的影响因素,而出口商的谈判能力、币值的对外稳定性等因素也对PCP的选择有一定影响。根据实证检验结果,对人民币作为贸易计价货币的条件进行评估,发现其优势在于我国的经济规模、出口商的市场份额及其谈判能力以及人民币汇率的相对稳定性; 劣势在于相对落后的金融市场、不可预期性较大的通货膨胀水平以及产品的差异化程度。     

La répartition régionale de la prime aux qualifications en Chine urbaine: implications sur la croissance et les inégalités

Les auteurs observent que la prime aux qualifications a augmenté dans toutes les régions de Chine entre 1995 et 2002, mais seulement dans les régions côtières entre 2002 et 2007. Ainsi, ces régions présentent de plus fortes inégalités salariales, notamment en zones urbaines. Si les privatisations ont été la première raison de la montée de la prime aux qualifications entre 1995 et 2002, entre 2002 et 2007 cela a été l'intégration, inégale selon les régions, à l'économie mondiale. Réduire cette prime et les inégalités suppose de réformer le système du hukou qui fait obstacle à la mobilité de la main‐d'?uvre, donc à la croissance.     

英国脱欧对中英贸易的影响分析

英国公投脱欧的决定,是由英国与欧盟长久以来的政治分歧与经济发展受限等原因,以及移民负担过重这一导火索共同推动的。对英国与欧盟的贸易关系进行分析,发现英国在欧盟中占据重要的贸易地位,与欧盟进出口贸易关系密切。对英国与中国的贸易现状进行分析,发现英国与中国的贸易发展良好,但贸易结合度不高。英国脱欧后,不再享有作为欧盟成员国的优惠贸易条件,可能产生中英进出口贸易额增多、贸易规模扩大、中英贸易顺差减小以及中英贸易政策出现新格局等影响。     

原产地多元化视角下的地方产业集群升级研究

地方产业集群升级是区域经济发展的重要研究主题,由于中国特别是东部地区产业集群具有"天生全球化"特质,基于价值链的集群升级理论在适用性上存在局限。本文以原产地多元化为切入点,依据产业集群嵌入全球价值链的程度,对其通过原产地多元化实现升级的途径进行探讨,并结合案例分析加以验证。进而提出基于原产地多元化实现地方产业集群升级的主要内容和政策建议,以期为现实的产业集群发展和区域经济政策制定提供启示。     

HIV/AIDS and other household shocks as catalysts of local commercialization of non‐timber forest products in Southern Africa

Local trade in non‐timber forest products (NTFPs) is increasing globally, yet the causes have been little studied. We examine household shock as a driver of NTFP trade in five southern African countries, with an emphasis on HIV/AIDS‐related illness and death. Over the past two years, 95% of trader households experienced at least one shock, with family illness and death recorded for 68% and 42% of households, respectively. Almost 40% had entered the trade because of HIV/AIDS‐related shocks. Additional shocks included natural disasters, crop pests or failure and livestock loss. The sale of NTFPs was the third most common coping strategy, after kinship and agricultural adjustments. Coping strategies differed between sites and type of shock.     

裂缝地层漏失规律研究

本文根据地下裂缝的漏失特性，建立了地下裂缝漏失规律的数学模型，并导出了各种流体在裂缝中的流动挽律。根据流动规律可以定量分析和计算漏速或漏失量与压差、裂缝尺寸、钻井液流变性能等之间的关系，这时优选优配堵漏荆的性能，选择合理的堵漏方法，提高防漏堵漏的成功率具有重要的指导意义。