按摩模式对揉捏式按摩椅按摩舒适性的影响

以揉捏式按摩椅作为研究对象,采用自由模量幅度估计法.通过对标准化后的按摩舒适度评价值分别进行统计,得到颈肩、背部和腰部区域3个区域共计8个测点最舒适的按摩模式,并通过脑电测试实验从客观角度验证了对由自由模量幅度估计法所得的各按摩区域最佳按摩模式的科学性,探讨了按摩模式对按摩椅按摩舒适性的影响.     

角质酶/表面活性剂体系对混合办公废纸的协同脱墨作用

角质酶能够水解可溶性酯、不溶性甘油三酯和各种聚酯，因此可以水解油墨中的连接料，有代替脂肪酶应用于废纸脱墨领域的潜能。利用角质酶和实验室复配得到的表面活性剂协同应用于混合办公废纸脱墨领域，探讨其脱墨效果和最优工艺，并与常用商业脂肪酶进行脱墨效果比较。结果表明，角质酶在酶用量10 U·g^-1，酶处理时间30 min，酶处理温度50℃，表面活性剂用量0.2%的条件下可以达到最优效果。与脂肪酶/表面活性剂以及单独用表面活性剂脱墨相比，角质酶脱墨后纸页的白度与油墨去除率更高，纸页的机械强度也较好。通过纸页性能的对比和扫描电镜（SEM）观察，角质酶的脱墨效果较脂肪酶更佳，角质酶/表面活性剂体系对混合办公废纸脱墨效果较好。     

A joint replenishment problem considering multiple trucks with shipment and resource constraints

A joint replenishment problem (JRP) is presented to determine the optimal reordering policy for multi-items with a percentage of defective items. This JRP also has several constraints, such as shipment constraint, budget constraint, and transportation capacity constraint. At the meantime, multiple trucks, each with a fixed transportation cost, are considered and also order quantities of restricted items are not shared among the trucks during the shipment. The objective is to minimize the total expected cost per unit time. A two-dimensional genetic algorithm (GA) is provided to determine an optimal family cycle length and the reorder frequencies. A numerical example is presented and the results are discussed. Extensive computational experiments are performed to test the performance of the GA. The JRP is also solved by using an evolutionary algorithm (EA) and the results obtained from GA and EA are compared.     

How do the internet technological developments shift the consumption pattern of paper products? Evidence from China

Using a monthly data between 2008 and 2019, this study investigated how the development of the Internet technologies has shaped the consumer consumption pattern of different types of paper products in China during this period. In detail, this study covers four major types of paper products in the Chinese market: newsprint, printing paper, household paper, and packaging paper. The developments of Internet technologies were decomposed into two aspects: the communication technology (CT) and the software platform technology (PT). Granger causality analysis was employed to determine whether the consumption pattern of paper products was affected by the development of the Internet. Furthermore, impulse-response analyses were utilized to measure how the consumption pattern of each paper product was shaped by the development of each aspect of Internet technologies, i.e., CT or PT. The empirical results suggested that the Internet developments are causing the consumption patterns shifts of all four paper products. Specifically, the consumptions of newsprint and printing paper were driven by both CT and PT. However, the consumptions of packaging paper and household paper were driven by the PT only. Compared to the development of CT, we found that the quick evolution of PT plays a more significant role in shifting people's consumption of paper products in China. The empirical results revealed by this study could provide valuable economics and policy implications to both academia and relevant industries.     

Origin of abnormal glass transition behavior in metallic glasses

In this paper, the phenomenon of two glass-transition-like appearance in the supercooled liquid region of metallic glasses was investigated. It is confirmed that this abnormal behavior is attributed to the transition process of an amorphous state from higher energy to lower energy. The amorphous state with higher energy comes from the uneven distribution of compositions in glasses, which is mainly caused by the component with significant differences in atomic size and nonnegative values of enthalpy of mixing. The results were verified by high resolution transmission electron microscopy and energy-dispersive spectrometry.     

Analysis of the risk-sharing ratio in PPP projects based on government minimum revenue guarantees

Public-private partnership (PPP) projects have been widely applied in infrastructure construction. A suitable risk distribution strategy is crucial for promoting negotiations between the government and investors. The government usually provides guarantees to investors to distribute risk. However, an excessive guarantee increases the government's financial burden, whereas an insufficient guarantee reduces the confidence of the investors participating in the project. In a minimum revenue guarantee (MRG), the government subsidizes the investors the difference between the actual revenue and the government guarantee line if there is a loss. In PPP power plant and highway projects, investors' revenues come from two sources: government guarantees and the project company's self-sale. To support project companies and to optimize the projects' benefits, the government should set a reasonable benchmark for purchase amounts. Based on the traditional principal-agent model, this paper introduces the reciprocal preference theory to analyze the risk-sharing ratio most suitable for the government. Then, an optimal incentive mechanism is established to guarantee the project's income. The results indicate that by setting a different guarantee strategy for different participants, the government can utilize reciprocal preference to incentivize investors to exert more effort during a partnership and avoid moral hazard.     

Determination of drivers for investing in cryptocurrencies through a fuzzy full consistency method-Bonferroni (FUCOM-F’B) framework

Cryptocurrencies have brought many innovations and discussions to economic life. Digital assets, which are very popular by investors, are frequently used for many purposes such as store of value, exchange, and speculation. It creates a research area that intentions cryptocurrency experts prioritize in crypto investments. In this paper, therefore, the fuzzy Full Consistency Method-Bonferroni (FUCOM-F’B) model is conducted to determine the priorities of drivers for investing in cryptocurrencies. The selected twenty-three drivers are classified based on five aspects, including functionality, financial, legal infrastructure, technology, and security. Based on the findings, “strong electronic encryption” and “use of digital signature” are the most significant drivers for preferring a cryptocurrency. A validation check is performed to verify the reliability, usefulness, and stability of the proposed approach. Further, the introduced approach allows taking the ambiguities and subjectivity into account which exist in the decision-making procedure. The suggested framework can be a helpful decision support tool for regulators, policymakers, practitioners, and cryptocurrency investors.     

Ru-doped 3D porous Ni3N sphere as efficient Bi-functional electrocatalysts toward urea assisted water-splitting

Developing efficient, stable and ideal urea oxide (UOR) electrocatalyst is key to produce green hydrogen in an economical way. Herein, Ru doped three dimensional (3D) porous Ni₃N spheres, with tannic acid (TA) and urea as the carbon and nitrogen resources, is synthesized via hydrothermal and low-temperature treated process (Ru–Ni₃N@NC). The porous nanostructure of Ni₃N and the nickel foam provide abundant active sites and channel during catalytic process. Moreover, Ru doping and rich defects favor to boost the reaction kinetics by optimizing the adsorption/desorption or dissociation of intermediates and reactants. The above advantages enable Ru–Ni₃N@NC to have good bifunctional catalytic performance in alkaline media. Only 43 and 270 mV overpotentials are required for hydrogen evolution (HER) and oxygen evolution (OER) reactions to drive a current of 10 mA cm^?2. Moreover, it also showed good electrocatalytic performance in neutral and alkaline seawater electrolytes for HER with 134 mV to drive 10 mA cm^?2 and 83 mV to drive 100 mA cm^?2, respectively. Remarkably, the as-designed Ru–Ni₃N@NC also owns extraordinary catalytic activity and stability toward UOR. Moreover, using the synthesized Ru–Ni₃N@NC nanomaterial as the anode and cathode of urea assisted water decomposition, a small potential of 1.41 V was required to reach 10 mA cm^?2. It can also be powered by sustainable energy sources such as wind, solar and thermal energies. In order to make better use of the earth's abundant resources, this work provides a new way to develop multi-functional green electrocatalysts.     

Effect of Pre-deformation on Decomposition and Spheroidization of M2C Carbide in High-Speed Steel

Metallurgical and Materials Transactions A - One key challenge for tailoring microstructure of high-speed steel (HSS) is to obtain small-sized carbides with a homogeneous distribution. Although...     

实木顺纹压缩弯曲技术研究现状及发展趋势

实木顺纹压缩弯曲技术蕴含着多学科知识的交叉融合,具有一定的理论深度和突出的实际应用性,是当今备受关注的研究热点之一文章论述了国内实木顺纹压缩弯曲技术的研究现状与发展趋势,描述了国内研究学者在树种选择、木材软化与顺纹压缩、木材弯曲等方面的研究成果,提出高效利用木材资源、提升自动化程度、提高木材弯曲精度的发展趋势,为今后国内实木顺纹压缩弯曲技术的研究提供借鉴。