Search

[Purpose/Significance] To explore the influencing factors of the added value of scientific data and reveal the inherent development laws of the added value of scientific data. [Method/Process] First, based on the interview data of 18 experts and the research results related to the value appreciation of scientific data in existing literature, the grounded theory method was adopted. Through open coding, main-axis coding, and selective coding, 19 categories, 6 main categories, and 3 core categories were finally obtained. From this, a theoretical model of the factors influencing the value appreciation of scientific data was obtained. On this basis, the Vensim PLE tool was used to establish a dynamic model of the value appreciation system of scientific data, and the process of value appreciation of scientific data was dynamically simulated and analyzed to reveal the relationship between various influencing factors and the value appreciation of scientific data. [Results/Conclusions] In the process of increasing the value of scientific data, the quality factor of raw data is a prerequisite, and high-quality raw scientific data are conducive to the integration and secondary development of subsequent scientific data. The data literacy of data producers represented by researchers has the most significant impact on the quality of scientific data. The level of data storage and payment has a significant impact on the added value of scientific data. When the perceived effort and perceived risk of data storage and payment by researchers decrease, accompanied by the pressure of scientific data sharing policies, researchers become more likely to increase their willingness to save and pay, thereby significantly improving the scale effect of data storage and payment. The organization and integration of scientific data is the key to the formation of value-added scientific data. Overall, the metadata quality has the most significant impact on the level of scientific data organization and integration. The quality of metadata is the foundation of scientific data processing, classification, and integration. The higher the quality of metadata, the more it helps to improve the level of scientific data organization and integration. The sharing and development of scientific data is the key to realizing the value-added of scientific data. It is the final step in realizing the value-added of scientific data. In this process, the scale of scientific data openness, the quality of scientific data sharing platforms, and development capabilities all have a positive promoting effect on the level of scientific data sharing and development.

Polymer blending is one of the most economical and effective techniques for achieving products with high comprehensive performances. However, the immiscibility between polymers results in a weak interface, which is typically the position where material failure starts when an external force is applied. Therefore, understanding and controlling the interfacial structure are important for controlling the failure behavior of polymer blends and achieving advanced materials. In this study, the related work was performed on a crystal/crystal blend of isotactic polybutene-1 and polyethylene (iPB-1/PE). The results indicated that iPB-1 and PE were partially miscible in a wide temperature window (140–220°C), and the phase separation of iPB-1/PE blends was retarded at 180°C, resulting in an increase in the interfacial thickness and interfacial adhesive strength when iPB-1/PE crystallized at a low temperature. In addition, the iPB-1/high-density PE (HDPE) samples exhibited higher interfacial adhesive strength than the iPB-1/linear low-density PE, which was attributed to the relative streamline chain structure and the wide molecular weight distribution of HDPE and improved the interpenetration, crystallization, and miscibility of iPB-1 and HDPE at the interface. During storage at room temperature, the interfacial adhesive strength of iPB-1/PE decreased because of the spontaneous crystal transition of iPB-1.

Information-centric networking (ICN) introduces in-network caching mechanism to enable routers to have content caching function, changing the network from IP addressing to content name addressing, aiming to better provide services for content distribution applications. However, interest flooding attack (IFA) will lead to the exhaustion of router resources and make it discard a large number of legitimate interest packets, thus becoming the “bane” of ICN security. Combined with human immune defense theory, a two-stage ICN secure routing mechanism is proposed to resist interest flooding attacks. During the immunization time, non-specific immunization is completed through immune feedback and isolation strategy to prevent the pending interest table (PIT) of the router from being maliciously occupied. However, non-specific immunity cannot alleviate persistent IFA attacks, so further specific immunity is completed through backtracking strategy to form immune memory and completely block interest flooding attacks. Experimental results show that the proposed routing mechanism can effectively resist interest flooding attacks, reduce resource depletion and invalid computation caused by attacks, and ensure network performance.

An attractive type of nanofiller-carbon nanofiber (CNF) was used to modify High-density Polyethylene (HDPE) and polymer blends (UH-HDPE) of HDPE and ultra-high molecular weight polyethylene (UHMWPE), and two-phase and three-phase nanocomposites were prepared via a two-step process including melt mixing and hot press. The effects of CNF addition and their dispersion on the dielectric properties of nanocomposites were investigated. The results show that CNFs are well dispersed in HDPE matrix, while they are not permeated into the UHMWPE. It is demonstrated that CNFs are distributed homogenously in two-phase CNF/HDPE composites and heterogeneously in three-phase CNF/UH-HDPE composites. The dielectric constant of nanocomposites is dramatically improved with higher CNF content. The highest dielectric constant in CNF/HDPE composites, 190 at 102 Hz, is achieved with CNFs above 10% (mass fraction, the same as below), which is about 50 times higher than that of pure HDPE. Simultaneously, the dielectric constant of CNF/HDPE composites shows high dependence on the frequency due to the existence of CNFs, compared with the independent dielectric constant of pure HDPE. The influence of CNFs on the dielectric constant of CNF/UH-HDPE composites is similar to that of CNF/HDPE composites. However, the dielectric constant of three-phase composites is higher than that of two-phase counterparts with the same CNF addition. Additionally, no obvious dielectric loss is exhibited in both nanocomposites with CNF concentration under 5%.

With the increase of the operation environment requirements for aero-engine, the thermal barrier coating technology is difficult to satisfy the development requirement of aero-engine in the aspects of thermo-physical properties and thermo-stability. The preparation techniques of thermal barrier coating, design and selection of thermal barrier coating material, and failure mechanism of thermal barrier coating are introduced. The up-to-date research of material for better thermo-physical properties and better performance in CMAS(CaO-MyO-Al2O3-SiO2) resistance are discussed, which provide a direction for further research on thermal barrier coatings.

Economic and trade cooperation between China and ASEAN countries has made new progress with the introduction of the concept of Belt and Road. In 2015, China and ASEAN formally signed the outcome document of negotiations on an upgraded free trade area, which shows that China-asean relations have became better. Enhancing the trade facilitation level of the Free Trade Area can improve the economic and trade exchanges between China and ASEAN. The premise of studying how to improve the trade facilitation level of Free Trade Area is to measure the trade facilitation level of free trade area. In this paper, trade facilitation is divided into four categories and 19 sub-indexes, and the measurement model of trade facilitation in free trade area is established to measure the trade facilitation level between China and ASEAN countries.

The progression of precancerous lesions to malignancy is often accompanied by increasing complexity of chromosomal alterations but how these alterations arise is poorly understood. Here we perform haplotype-specific analysis of chromosomal copy-number evolution in the progression of Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC) on multiregional whole-genome sequencing data of BE with dysplasia and microscopic EAC foci. We identify distinct patterns of copy-number evolution indicating multigenerational chromosomal instability that is initiated by cell division errors but propagated only after p53 loss. While abnormal mitosis, including whole-genome duplication, underlies chromosomal copy-number changes, segmental alterations display signatures of successive breakage-fusion-bridge cycles and chromothripsis of unstable dicentric chromosomes. Our analysis elucidates how multigenerational chromosomal instability generates copy-number variation in BE cells, precipitates complex alterations including DNA amplifications, and promotes their independent clonal expansion and transformation. In particular, we suggest sloping copy-number variation as a signature of ongoing chromosomal instability that precedes copy-number complexity. These findings suggest copy-number heterogeneity in advanced cancers originates from chromosomal instability in precancerous cells and such instability may be identified from the presence of sloping copy-number variation in bulk sequencing data.

Cyclic CO2 flooding is an efficient method to enhance oil recovery in ultralow permeability reservoirs. As the demand for low carbon economy development, co-optimization of CO2 storage and utilization should be considered. In this research, initially a comprehensive optimization method was proposed, which co-optimize oil recovery and CO2 storage by different weighting factors. Then, a series of core flooding experiments were performed using the core samples collected from Changqing oilfield, which is a ultralow permeability reservoir with heterogeneity and micro-cracks, CO2 injection parameters of slug size and Injection-Soaking Time Ratio (ISR) were optimized. The results revealed that the optimal injection parameters changed for different optimization objectives. In the case where equal important to oil recovery and CO2 storage were considered, the optimum CO2 injection parameters in the ultralow permeability reservoirs were 0.03PV for slug size and 1:1 for ISR. Comparing the method of oil recovery optimization (ω 1 = 1) to co-optimization of oil recovery and CO2 storage (ω 1 = ω 2 = 0.5), oil recovery was reduced by 8.93%, CO2 storage was significantly increased by 25.85%. The results provide an insight into parameter optimization of CO2 enhanced oil recovery design.