对ASON承载IP网的研究(上)

随着业务的发展,IP网逐渐成为统一的多业务分组传送平台,应提供更为严格的可靠性保障机制,其目标不仅是要保障任何情况下的业务连通性,还要保证业务的QoS指标.ASON能快速地提供端到端连接,并能提供多种保护恢复机制,提高网络可靠性.如果采用ASON来承载IP网,则ASON可以为IP网提供保护恢复机制.本文主要探讨ASON承载IP网的需求,研究ASON为IP网提供保护恢复的可行性,从IP网和ASON的保护恢复现状、ASON为IP网提供保护恢复的技术和经济性方面进行详细的分析.     

立式气旋浮装置处理油田采出水的现场实验与应用改进措施

立式气旋浮装置凭借其紧凑、高效的特点在海上油田采出水处理领域得到了广泛应用,但国内围绕该技术的自主研发起步相对较晚,目前仍未推出具有完全自主知识产权的高性能系列化产品。基于自主设计研发的BIPTCFU-Ⅲ-120型立式气旋浮装置工业样机,在南海流花11-1油田的“南海胜利号”FPSO开展了现场实验研究。单因素变化运行结果表明,除油率受分流比、微气泡发生器与气旋浮罐间压差及进水流量变化的影响显著,受注气比、回流比变化的影响较小。稳定运行结果表明,当入口水含油质量浓度在240～400 mg/L之间时,优选组合操作参数下的除油率平均可达85%以上(最高可达91.8%),水出口含油质量浓度可降低到50 mg/L以下。结合工业样机现场实验结果,从工艺流程简化、微细气泡发生、立式罐体结构优化等角度进行了分析探讨,以促进相关技术的国产化进程及推广应用。     

变工况滚动轴承故障诊断方法综述

智能制造背景下,旋转机械工况更加复杂,运行条件更加严峻,设备的运行状态监测与故障诊断更加重要。变工况条件下,轴承振动信号存在幅值变、脉动冲击间隔、采样相位不恒定和信号噪声污染等特点,传统滚动轴承故障诊断方法的应用受到了限制。针对变工况条件下的轴承故障诊断技术,发展了以阶次跟踪、时频分析、随机振动以及混沌理论等人工提取特征的信号解调与分析方法、以卷积神经网络、自编码器与深度置信网络为代表的深度学习方法以及迁移学习方法。回顾近五年变工况轴承故障诊断领域的进展,从算法原理、算法优化以及算法实际应用等角度,详细介绍几种当前主流的变工况故障诊断方法,讨论各类算法的优势不足及适用场景,为后续的研究指明方向。     

Analysis of 2D flow and heat transfer modeling in fracture of porous media

Heat and mass transfer between porous media and fluid is a complex coupling process,which is widely used in various fields of engineering applications,especially for natural and artificial fractures in oil and gas extraction.In this study,a new method is proposed to deal with the flow and heat transfer problem of steady flow in a fracture.The fluid flow in a fracture was described using the same method as Mohais,who considered a fracture as a channel with porous wall,and the perturbation method was used to solve the mathematical model.Unlike previous studies,the shear jump boundary condition proposed by Ochoa-Tapia and Whitaker was used at the interface between the fluid and porous media.The main methods were perturbation analysis and the application of shear jump boundary conditions.The influence of permeability,channel width,shear jump degree and effective dynamic viscosity on the flow and heat transfer in the channel was studied by analysing the analytical solution.The distribution of axial velocity in the channel with the change of the typical parameters and the sensitivity of the heat transfer was obtained.     

谈进口铁矿石中的有害元素

概述铁矿石中常见的有害伴生元素及其对冶炼、环境和人体健康的影响;介绍宁波口岸对进口铁矿石中12种有害元素含量的抽查情况,并对抽查结果进行分析;指出一些进口铁矿石存在不同程度的重金属污染的风险,应引起高度重视.     

Recent advances during CH4 dry reforming for syngas production: A mini review

Given the continuing issues of environment and energy, methane dry reforming for syngas production have sparked interest among researchers, but struggled with the process immaturity owing to catalyst deactivation. This review summarizes the recent advances in the development of efficient and stable catalysts with strong resistance to coking and metal sintering, including the application of novel materials, the assessment of advanced characterizations and the compatibility to improved reaction system. One feasible option is the crystalline oxide catalysts (perovskite, pyrochlore, spinel and LDHs), which feature a fine metal dispersion and surface confinement effect via a metal exsolution strategy and exhibit superior reactivity and stability. Some new materials (h-BN, clays and MOFs) also extend the option because of their unique morphology and microstructure. It also is elaborated that progresses were achieved in advanced characterizations application, leading to success in the establishment of reaction mechanisms and attributions to the formed robust catalysts. In addition, the perspective described the upgrade of reaction system to a higher reaction efficiency and milder reaction conditions. The combination of efficient reaction systems and robust catalysts paves a way for a scaling-up application of the process.     

直接测力俯仰振荡翼型动态气动性能研究

在西北工业大学NF-3低速风洞二元实验段开展翼型俯仰振荡运动动态气动性能深入研究。实验模型为展向三段式测力模型,测力仅在模型中段进行以减小风洞侧壁干扰的影响。实验中采集模型的转动瞬态迎角、计算模型中段的惯性力和惯性力矩、并从天平采集数据中扣除以修正模型惯性对结果的影响。结果表明,迎角超过正向或负向静态失速迎角是升力系数和俯仰力矩系数产生大的迟滞环的必要条件。随着振荡缩减频率增大,动态失速会推迟,升力系数迟滞环增大,阻力系数增大,最大迎角附近的俯仰力矩系数减小。在迎角小于静态失速迎角或超过不大的迎角范围,随着缩减频率的增大,翼型振荡运动俯仰力矩系数上行时减小,下行时增大。随着振荡振幅的增大,翼型振荡运动动态升力系数和俯仰力矩系数的迟滞环增大。随着平均迎角的增大,翼型迎角更多地进入正向失速区,升力系数迟滞环增大,俯仰力矩系数最小值变小。雷诺数对升力系数、阻力系数和俯仰力矩系数迟滞环无明显影响;但是,在翼型模型下行过程,随着雷诺数的增大,升力恢复提前,同时迟滞环随雷诺数增大而减小。     

碘在生物样品消解和灰化过程中的丢失研究

用＾１３１Ｉ示踪和中子活化法测定了碘在生物样品酸消解和灰化处理中回收率。结果表明：Ｄ 不同酸消化条件下碘的回收率差别很大。当ＨＮＯ３和ＣＨｌＯ４作消化液、用冷却水回流消解时，生物样品中碘的回收率可达９５％以上。用ＫＯＨ在６５０℃灰化时，回收率可达９０％以上。     

A New NTRU-Type Public-Key Cryptosystem over the Binary Field

As the development of cloud computing and the convenience of wireless sensor netowrks, smart devices are widely used in daily life, but the security issues of the smart devices have not been well resolved. In this paper, we present a new NTRU-type public-key cryptosystem over the binary field. Specifically, the security of our scheme relies on the computational intractability of an unbalanced sparse polynomial ratio problem (DUSPR). Through theoretical analysis, we prove the correctness of our proposed cryptosystem. Furthermore, we implement our scheme using the NTL library, and conduct a group of experiments to evaluate the capabilities and consuming time of encryption and decryption. Our experiments result demonstrates that the NTRU-type public-key cryptosystem over the binary field is relatively practical and effective.     

Transforming the fermented fish landscape: Microbiota enable novel,safe, flavorful,and healthy products for modern consumers

Regular consumption of fish promotes sustainable health while reducing negative environmental impacts. Fermentation has long been used for preserving perishable foods, including fish. Fermented fish products are popular consumer foods of historical and cultural significance owing to their abundant essential nutrients and distinct flavor. This review discusses the recent scientific progress on fermented fish, especially the involved flavor formation processes, microbial metabolic activities, and interconnected biochemical pathways (e.g., enzymatic/non-enzymatic reactions associated with lipids, proteins, and their interactions). The multiple roles of fermentation in preservation of fish, development of desirable flavors, and production of health-promoting nutrients and bioactive substances are also discussed. Finally, prospects for further studies on fermented fish are proposed, including the need of monitoring microorganisms, along with the precise control of a fermentation process to transform the traditional fermented fish to novel, flavorful, healthy, and affordable products for modern consumers. Microbial-enabled innovative fermented fish products that consider both flavor and health benefits are expected to become a significant segment in global food markets. The integration of multi-omics technologies, biotechnology-based approaches (including synthetic biology and metabolic engineering) and sensory and consumer sciences, is crucial for technological innovations related to fermented fish. The findings of this review will provide guidance on future development of new or improved fermented fish products through regulating microbial metabolic processes and enzymatic activities.