Optimized decomposition and two-step nonlinear integration model with error correction strategy coupled interval prediction for digital currency price forecast

Digital currency price prediction is vital to both sellers and purchasers. Over these years, decomposition and integration models have been applied more and more to realize the goal of precise prediction, however, many of them tend to neglect the reconstruction of features or the residual series. Altogether, one of the biggest drawbacks of the decomposition and integration framework is the method applied requires manual parameter setting whether it is for decomposition or integration. Still, for the results, they are merely satisfied with the point prediction which brings high uncertainty. In this paper, an optimized feature reconstruction decomposition and two-step nonlinear integration method is proposed which gives consideration to feature reconstruction, nonlinear integration, optimization and interval prediction. The original data series is decomposed through improved variational mode decomposition based approximate entropy feature reconstruction system. Then, improved particle swarm optimization-gated recurrent unit (iPSO-GRU) is utilized in the first and second nonlinear integration part separately. Meanwhile, the residual series is given attention, if it is not a white noise series, the residual will be the input of iPSO-GRU whose result will be added back to the second integration result to form the point prediction result. Based on the point prediction result, interval prediction estimate will be generated as well via maximum likelihood function. This study chooses three kinds of digital currency as cases and the results show that the MAPE values of point prediction are all below 3.5%, and CP values of interval prediction are all 1 with suitable MWP. In addition, compared with other benchmark models, the proposed model shows better performance.

     

建筑隔震橡胶支座用低模量高阻尼胶料的研究

对建筑隔震橡胶支座用低模量高阻尼胶料进行研究。结果表明：选用粒径小和比表面积大的炭黑、增大炭黑用量以及增大增粘树脂用量有利于降低胶料的剪切模量；为保证胶料的剪切模量介于0.3～0.5 MPa之间，胶料需加入一定量的增塑剂。     

The application and prospects of cyclodextrin inclusion complexes and polymers in the food industry: a review

Cyclodextrin is an odorless and tasteless cyclic oligosaccharide widely used in various fields such as food, medicine and the environment. Cyclodextrin can improve solubility and stability, and can mask the bad taste of specific substances. Cyclodextrins and their polymers primarily act by forming complexes in foods, and can be applied in food packing, food analysis, enhancing the properties of antioxidants, antibacterials, for stability and so on. The challenges and opportunities facing this area are reviewed. It is hoped that the review will provide useful information for future applications of cyclodextrin in the food industry. © 2020 Society of Chemical Industry     

Research on Wind Turbines Fault Diagnosis Technology Based on CMS Data Feature Extraction

Wireless Personal Communications - As a rich clean and environmentally friendly renewable resources, wind energy has emerged as a strategic choice for countries around the world. Because the...     

Flexible and Highly Sensitive Strain Sensors Fabricated by Pencil Drawn for Wearable Monitor

Functional electrical devices have promising potentials in structural health monitoring system, human‐friendly wearable interactive system, smart robotics, and even future multifunctional intelligent room. Here, a low‐cost fabrication strategy to efficiently construct highly sensitive graphite‐based strain sensors by pencil‐trace drawn on flexible printing papers is reported. The strain sensors can be operated at only two batteries voltage of 3 V, and can be applied to variously monitoring microstructural changes and human motions with fast response/relaxation times of 110 ms, a high gauge factor (GF) of 536.6, and high stability >10 000 bending–unbending cycles. Through investigation of service behaviors of the sensors, it is found that the microcracks occur on the surface of the pencil‐trace and have a major influence on the functions of the strain sensors. These performances of the strain sensor attain and even surpass the properties of recent strain sensing devices with subtle design of materials and device architectures. The pen‐on‐paper (PoP) approach may further develop portable, environmentally friendly, and economical lab‐on‐paper applications and offer a valuable method to fabricate other multifunctional devices.     

HT-7托卡马克中逃逸电子和磁场波纹的共振作用

为抑制托卡马克等离子体中逃逸电子的能量,在2009年秋HT-7托卡马克物理实验中,分析了逃逸电子在不同放电条件下的能量演化信息,发现逃逸电子和磁场波纹的共振现象.尽管在等离子体的芯部,逃逸电子的能量可高达数十MeV,但在逃逸电子输运到边界的过程中,通过和磁场波纹不同阶的谐波共振,逃逸电子的能量被限制在一个范围内,而不会...     

低气压环境被服系统总热阻计算模型

服装热阻是影响人体热舒适的重要因素之一,夜间睡眠状态下的被服系统总热阻包括人体所穿服装热阻与整个床褥系统热阻。针对低气压环境,目前,尚缺乏被服热阻实验数据,也没有可参考的被服系统总热阻的理论计算模型。以人体睡眠状态被服系统总热阻计算方法为依据,引入气压修正项对相关参数进行修正,建立了适用于低气压环境的被服系统总热阻的修正计算模型,并用模型计算了冬夏典型被服系统总热阻,分析了气压减小对总热阻的影响,发现冬夏季被服系统总热阻均随大气压力降低而升高,增加百分比最大值均为42%,且均出现在被子覆盖率为23.3%的条件下,当海拔低于3 000m时,由被子覆盖率引起的被服系统总热阻增加系数不超过0.05。     

软土地区城市中心区深基坑土方开挖施工技术

通过对比分析,阐述了在软土地区城市中心区深基坑多道支撑下,土方开挖过程中选择不同的施工技术对挖土进程、经济效益的影响有所不同。针对工程特点,创造性地采用钢板桩作为出土坡道的临时挡土墙,并利用对撑与出土坡道形成有效出土通道的方式进行土方开挖,可达到快速、安全、经济的效果。同时首道支撑兼作堆料平台,充分缓解了城市中心区现场用地紧张的现状,降低了工程造价。     

国产高钢级连续油管在川渝页岩气开发中的应用

针对进口油管价格高、供货周期长等现状,结合川渝页岩气藏的地质特征,采用国产高钢级连续油管在川渝页岩气井中进行施工作业,对国产高钢级连续油管和进口连续油管的使用寿命、下井次数以及平均下井时间进行了对比,并对连续油管在页岩气藏中的应用进行了介绍。结果表明,国产高钢级连续油管质量合格、性能稳定,在某些方面甚至优于进口连续油管,能在多种复杂环境中作业,完全满足川渝页岩气藏储层改造的施工要求,可替代进口油管从而为油田降本增效。     

Facile nano‐free electrochemiluminescence biosensor for detection of sulphamethoxazole via tris(2,2′‐bipyridyl)ruthenium(II) and N ‐methyl pyrrolidone recognition

The electrochemiluminescence (ECL) system based on the ruthenium complex has become a powerful tool in the field of analytical chemistry. However, the non‐aqueous ECL luminescence system, which does not involve complex nano‐modification, has not been widely used for the determination of analytes. In this study, N ‐methyl pyrrolidone was selected as the solvent, and it could also act as a co‐reactant of Rubpy32+. Based on this, a simple ECL system without nanomaterials was established. Strong ECL was generated. Furthermore, a quenching effect between the excited state of Rubpy32+ and sulphamethoxazole (SMZ) was observed. Based on this, a sensitive ECL sensor for detecting SMZ is constructed. A linear relationship between ECL signal quenching intensity (ΔI) and the logarithm of SMZ concentration (log C) in the concentration range of 1 × 10⁻⁷ –1 × 10⁻⁵ mol/l is obtained. The limit of detection is as low as 3.33 × 10⁻⁹ mol/l. The method has been applied to the detection of SMZ in tap water samples with different concentration levels with satisfactory results, and the recovery was 95.3–102.6%.Inspec keywords: biosensors, electrochemical sensors, electroluminescence, chemiluminescence, organic compounds, electrochemistryOther keywords: ruthenium complex, analytical chemistry, nonaqueous ECL luminescence system, complex nanomodification, quenching effect, ECL signal quenching intensity, ECL sensor system, nanofree electrochemiluminescence biosensor system, sulphamethoxazole detection, tris(2,2′‐bipyridyl)ruthenium(II), N‐methyl pyrrolidone recognition, analyte determination, nanomaterials, SMZ concentration detection