Safety Length Simulation of Natural Gas Pipeline Subjected to Transverse Landslide

The safety of natural gas pipeline is often severely threatened by the transverse landslide. At home and abroad, it is the first time to study the safe length of the pipeline when affected by landslide, and take the safe length of the pipeline as an engineering practical index. Therefore, it is of great significance to study the influence of transverse landslide affecting the safety of natural gas pipeline when a certain length of pipeline is thrusted, and to establish practical index and simulation method for prediction and prevention of the landslide hazards to gas pipeline. Based on the current research results, this study could be divided into three steps: First of all, with the help of ANSYS finite element software, the model of transverse landslide acting on the gas pipeline can be set up, then the length value of gas pipeline safely withstanding transverse landslide can be calculated;Secondly, using the strength reduction method, which is commonly used in the research of landslide stability, can establish three-dimensional model of the landslide and pipes in the ABAQUS finite element software, next, under the same landslide pushed length, the calculation results will be obtained;Finally, to draw reliable conclusions, all calculated results of the former two methods will be linked to synthetically and comparatively analyze, then the length value of common X80 gas pipeline safely bearing transverse landslide can be got. All results can provide some references for engineering and design.

Effect of pressure cooking on phenolic compounds of quinoa

Due to good nutritional properties and potential health benefits,quinoa has gained an increasing attention.The study aimed to analyze the effect of pressure cooking on the composition,antioxidant activity,antibacterial activity and bioavailability of phenolic compounds in four types of quinoa,and to evaluate the correlation between phenolics and its biological activities by correlation analysis.The results showed that different varieties of quinoa contained different phenolic components and their biological activities were different.Pressure cooking could significantly increase(P<0.05)the phenolic contents of quinoa,and decrease in vitro digestibility of protein.The antioxidant activity,antibacterial activity and bioavailability of quinoa were also enhanced which were positively related with phenolic contents.HPLC analysis indicated that at least twelve phenolic compounds were found in quinoa,and hyperoside,sinapic acid,rutin and ferulic acid occupied a majority of them.Correlation analysis suggested that hyperoside,quercetin,sinapic acid,ferulic acid and gallic acid made the key contribution to antioxidant and antibacterial activities of phenolic compounds of quinoa.The results provided valuable information for quinoa processing with phenolics as functional ingredient.

Reversible Optical Isolators and Quasi-Circulators Using a Magneto-Optical Fabry-Pérot Cavity

Nonreciprocal optical devices are essential for laser protection,modern optical communication and quantum information processing by enforcing one-way light propagation.The conventional Faraday magneto-optical nonreciprocal devices rely on a strong magnetic field,which is provided by a permanent magnet.As a result,the isolation direction of such devices is fixed and severely restricts their applications in quantum networks.In this work,we experimentally demonstrate the simultaneous one-way transmission and unidirectional reflection by using a magneto-optical Fabry-Pérot cavity and a magnetic field strength of 50 mT.An optical isolator and a three-port quasi-circulator are realized based on this nonreciprocal cavity system.The isolator achieves an isolation ratio of up to 22 dB and an averaged insertion loss down to 0.97 dB.The quasi-circulator is realized with a fidelity exceeding 99% and an overall survival probability of 89.9%,corresponding to an insertion loss of~0.46 dB.The magnetic field is provided by an electromagnetic coil,thereby allowing for reversing the light circulating path.The reversible quasi-circulator paves the way for building reconfigurable quantum networks.

A Novel Dual Helical Magnetorheological Fluid Micro-Robot

To address the problem of flexible drive control of gastrointestinal(GI)tract micro-capsule robot posture,a novel dual helix magnetorheological fluid(MRF)micro-robot(DHMRFMR)is proposed and developed in this paper.Based on the mechanical properties of magnetorheological fluid,the relationship model of magnetic field force is obtained,and the thrust model is established.Double micro DC deceleration motor is used to drive the two ends of the helical actuator to make the DHMRFMR forward and backward,by changing the external magnetic field rotation speed,direction and distance,adjust the attitude direction of the robot.Numerical simulation software ANSYS is used to analyze the motion law of external fluid of DHMRFMR,and the visualization of fluid velocity and pressure distribution is realized.The front-end helix actuator can change the flow path of the fluid,and the middle and tail of the DHMRFMR bear less pressure,which improves the stability and flexibility of the robot.The novel DHMRFMR is suitable for internal drive in bending environment,and has a good application prospect in biomedical engineering field in human intestinal unstructured environment.

Efficient continuous synthesis of 2-hydroxycarbazole and 4-hydroxycarbazole in a millimeter scale photoreactor

2-Hydroxycarbazole and 4-hydroxycarbazole are important chemicals with extensive applications in optoelectronic materials and pharmaceutical field.State of the art yield of 2-hydroxycarbazole is~30%and the reaction time is typically in hours or days.Herein,we developed a green route for the continuous and high-throughput synthesis of 2-hydroxycarbazole and 4-hydroxycarbazole via photochemical intramolecular cyclization of 3–hydroxy-2–chloro-diphenylamine using a self-designed millimeter scale photoreactor,which was designed based on sizing-up and numbering-up strategies for a decent liquid holdup(6.8 m L)and fabricated via femtosecond laser engraving technique.The photochemical synthesis was carried out continuously under the illumination of 365 nm UV-LED with dimethyl sulfoxide as solvent and potassium t-butoxide as catalyst.It was found that under optimized conditions a 2-hydroxycarbazole yield of 31.6%and a 4-hydroxycarbazole yield of 11.1%were obtained with a residence time of 1 min.Compared to semibatch operations,the reaction time was shortened by 1–2 orders of magnitude.As a result,a throughput of 11.3 g/day 2-hydroxycarbazole and 4.0 g/day 4-hydroxycarbazole can be achieved from the photoreactor.It was proposed that the short reaction time and high product yield are resulted from higher photon transfer rates and more uniform photon distribution provided by the millimeter scale photoreactor,which enhances the reaction rates and mitigates overreaction.

Study on the static properties of spiral springs under static loading

Spiral springs have a wide range of applications in various fields.As a result of the complexity of friction,few theoretical analyses of spring belts under static loading have been carried out.Considering the piecewise smooth property of the whole contact area,a simplified static model of spiral springs under loading is established in this paper.Besides,three main stress and friction distribution areas of the spring belt are proposed,namely,internal,transitional,and external regions.Since the outermost side of the spring is not subject to any pressure,a recursive method is adopted from the outside to the inside.The model provides the parameter conditions,i.e.,the internal and external forces are independent or dependent.Therefore,the case that the whole contact region of the spring belt has one subregion,two subregions,and three subregions is obtained.The model gives a theoretical basis for the parameter optimization of spiral springs.

Preparation and Electrorheological Response of PAL/TiO_(2)/PANI Nanorods

Using palygorskite(PAL)as template,the PAL/TiO_(2)/PANI nano-rods were synthesized by heterogeneous precipitation and in-situ polymerization.The synthesized PAL/TiO_(2)/PANI nanorods were used as a novel electrorheological(ER)fluid by mixing with silicone oil,which showed excellent ER effect.The yield stress of the PAL/TiO_(2)/PANI based ER fluid(15 vol%)reached 8.8 kPa under 4 kV mm^(−1) electric field.The dynamic shear stress of the PAL/TiO_(2)/PANI based ER fluid could maintain a stable level in the shear rate range of 0.1–100 s^(−1).Furthermore,the PAL/TiO_(2)/PANI ER fluid exhibited excellent suspension stability.

面向效果的线上教学设计模式研究

针对网络教学条件下学生学习积极性不高、学习效果难以保证的问题,分析了学生网络在线学习条件下的心理特征,以心流体验理论、社会临场感理论、建构主义学习理论为理论基础,提出“优化教学内容(Content)+深化课堂互动(Interaction)+优化过程评估机制(Evaluation)”的C-I-E教学设计模式,并阐述了优化教学内容的方法、深化课堂互动的途径、优化过程评估机制的原则。经过《毛泽东思想和中国特色社会主义理论体系概论》课程的实践检验,证明这种教学设计模式对于提升教学效果是有效的,对教师网络教学条件下教学设计工作具有参考价值。

人工智能在能源与电力系统中的应用介绍

近年来,人工智能在视觉识别、自然语言处理等领域表现出卓越的能力,其在计算智能、感知智能和认知智能的深度化成为研究热点。目前,人工智能已在能源与电力系统中得到初步应用,推动了电力行业的进步和发展。基于此,本文介绍了人工智能相关技术方法,同时总结了专家系统、机器学习等人工智能技术运用于能源与电力行业中的相关优势,并展望了人工智能技术在能源与电力中的应用前景与潜力。

IMPULSIVE BOUNDARY VALUE PROBLEMS FOR STURM-LIOUVILLE TYPE DIFFERENTIAL INCLUSIONS

在这篇论文，作者调查 Sturm-Liouville 类型的冲动的边界价值问题的答案的存在在右手上承认 non-convex-valued 多功能的微分包括站在一起。在更弱的条件下面的二结果被介绍。方法为收缩依靠一条固定的点定理多珍视的地图由于 Covitz；Nadler；Schaefer 的固定的点定理与 decomposable 价值与更低的半连续的多珍视的操作员结合了。

Recent progress in flexible organic solar cells

Photovoltaic cells are one of the most promising renewable energy sources to address energy and environmental issues.Amongst the many photovoltaic technologies,organic solar cells(OSCs)have numerous advantages,such as low cost,light weight,semi-transparency,and flexibility.This last is a special merit of OSCs,arising due to the intrinsic flexibility of organic active layers.With promising applications in fields such as building-integrated photovoltaics and wearable electronics,flexible OSCs(F-OSCs)have developed rapidly,and significant process has been made in recent years.In this review,we summarize the recent progress in F-OSCs from the perspective of flexible transparent electrodes.In addition,large-area F-OSCs and their potential applications are briefly dis-cussed.Finally,challenges for the further development of F-OSCs are presented.

Performance Evaluation of an Anomaly-Detection Algorithm for Keystroke-Typing Based Insider Detection

Keystroke dynamics is the process to identify or authenticate individuals based on their typing rhythm behaviors. Several classifications have been proposed to verify a user＇s legitimacy, and the performances of these classifications should be confirmed to identify the most promising research direction. However, classification research contains several experiments with different conditions such as datasets and methodologies. This study aims to benchmark the algorithms to the same dataset and features to equally measure all performances. Using a dataset that contains the typing rhythm of 51 subjects, we implement and evaluate 15 classifiers measured by Fl-measure, which is the harmonic mean of a false-negative identification rate and false-positive identification rate. We also develop a methodology to process the typing data. By considering a case in which the model will reject the outsider, we tested the algorithms on an open set. Additionally, we tested different parameters in random forest and k nearest neighbors classifications to achieve better results and explore the cause of their high performance. We also tested the dataset on one-class classification and explained the results of the experiment. The top-performing classifier achieves an Fl-measure rate of 92% while using the normalized typing data of 50 subjects to train and the remaining data to test. The results, along with the normalization methodology, constitute a benchmark for comparing the classifiers and measuring the performance of keystroke dynamics for insider detection.