70 research outputs found

    Comprehensive Credit Risk Management of Policy Export Credit Insurance Institutions

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    In the context of the turbulent international political situation, the uneven development of social development and the stagnation of economic development in recent years, China's promotion of foreign trade and economic transformation and upgrading and the “Belt and Road” strategy are necessary to pay more attention to the research and control of export credit risks, so policy exports is particularly urgent and important for credit insurance institutions to conduct research on credit risk control activities in support of the “going out” process of Chinese goods and capital. At the same time, unlike general commercial financial institutions, the starting point and foothold of credit risk management of policy financial institutions should be “maximizing social benefits” rather than the “maximum economic benefits” of traditional risk management theories. The target set of the risk management system of the export credit insurance institution is repositioned. Therefore, this paper attempts to sort out the research results of the existing policy-oriented export credit institutions, and from the perspective of comprehensive risk management, through the analysis of the characteristics and difficulties of the credit risk management of policy-oriented export credit insurance institutions, the company builds a comprehensive credit risk management system. The ideas and structure are discussed, and preliminary suggestions are put forward on the basis of this, in order to provide reference for the company to further improve the comprehensive risk management system

    Texture evolution induced by twinning and dynamic recrystallization in dilute Mg-1Sn-1Zn-1Al alloy during hot compression

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    Texture evolution of an extruded dilute Mg-1Sn-1Zn-1Al alloy was thoroughly investigated based on the twinning and dynamic recrystallization (DRX) behavior via hot compression at a strain rate of 10 s−1 and temperature of 225°C. It was found that the types and intensities of the texture are strongly dependent on the fraction of twins and DRX modes as well as regions where sub-grain boundaries (sub-GBs) are intensively accumulated. At the initial stage of deformation, the formation of compression direction (CD)-tilted basal texture was mainly determined by the occurrence of {101¯2} extension twins. As the strain increases, the variation in the texture intensity was greatly dominated by the DRX modes but the type of main texture remained unchanged. These findings are of great importance for texture modification of wrought Mg-Sn-based alloys during post-deformation

    The estimation of crop emergence in potatoes by UAV RGB imagery

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    Abstract Background Crop emergence and canopy cover are important physiological traits for potato (Solanum tuberosum L.) cultivar evaluation and nutrients management. They play important roles in variety screening, field management and yield prediction. Traditional manual assessment of these traits is not only laborious but often subjective. Results In this study, semi-automated image analysis software was developed to estimate crop emergence from high-resolution RGB ortho-images captured from an unmanned aerial vehicle (UAV). Potato plant objects were extracted from bare soil using Excess Green Index and Otsu thresholding methods. Six morphological features were calculated from the images to be variables of a Random Forest classifier for estimating the number of potato plants at emergence stage. The outputs were then used to estimate crop emergence in three field experiments that were designed to investigate the effects of cultivars, levels of potassium (K) fertiliser input, and new compound fertilisers on potato growth. The results indicated that RGB UAV image analysis can accurately estimate potato crop emergence rate in comparison to manual assessment, with correlation coefficient (r2 r^{2} r2 ) of 0.96 and provide an efficient tool to evaluate emergence uniformity. Conclusions The proposed UAV image analysis method is a promising tool for use as a high throughput phenotyping method for assessing potato crop development at emergence stage. It can also facilitate future studies on optimizing fertiliser management and improving emergence consistency

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∌99% of the euchromatic genome and is accurate to an error rate of ∌1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Management response to negative comments, psychological distance and product nature: a consumer perspective

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    Purpose – Management response to consumer comments has become a widely adopted marketing strategy to address the undesirable effects caused by negative remarks. Yet, when and what management response is more effective and under what circumstances remains under-researched. This study aims to fill this gap. Design/methodology/approach – In three experiments using five different products, the authors manipulate psychological construal level (psychological distance: distant vs proximal) and management response (response of primary vs secondary features) and thereafter assess their bearings on consumer psychological and behavioral reaction toward products of two distinctive natures (hedonic vs utilitarian). Findings – At a psychological distance, consumers show a preferable reaction to management response of primary over secondary features. In contrast, when the psychological distance is proximal, consumers react more positively to management response of secondary than primary features. In addition, these effects vary as a function of product nature, hedonic vs utilitarian. Research limitations/implications – The findings of this research bring a significant contribution to marketing communication literature and extend the construal level theory. Practical implications – A better understanding of the relative effectiveness of distinct types of management response to negative consumer comments is essential for more targeted and effective marketing strategies. Originality/value – Little research has documented the effects of distinct types of management response. How psychological distance might underpin these effects has not been explored. In addition, whether the interaction effect of management response and psychological distance varies with differences in product nature, namely, hedonic and utilitarian, remains unanswered until this research

    Improving the signal resolution of semiconductor gas sensors to high-concentration gases

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    Detecting high-concentration gases is challenging by metal oxide semiconductor (MOX) gas sensors, because the voltage signal would become saturated. In order to solve this problem, the zooming p + n field-effect transistors (FETs) circuit has been designed, combining an n-type enhancement-mode FET (EMFET) and a p-type depletion-mode FET (DMFET). This designed zooming p + n FETs can endow MOX gas sensors with the high signal resolution of similar to 3.0 V/decade to the 100-2000 ppm (part per million) acetone gas, triple that of MOX gas sensors without FETs (similar to 0.8 V/decade). Meanwhile, this zooming technology is also suitable for detecting other gases at high-concentration, such as 1%-20% LEL (lower explosion limit) methane. The principle of zooming p + n FETs is that with increasing the gas concentration, the suppressing role of the EMFET is firstly induced leading to a reduced signal resolution to the low-concentration target gas; then its suppressing effect becomes saturated and the DMFET starts to switch from ON state to OFF state in the high-concentration target gas, resulting in an amplifying effect herein and thus an enhanced signal resolution. This circuit is promising for the high-concentration gas detection as well as for the multi-functional gas detector design

    Interface-position-dependent structure evolution and mechanical behavior of corrugated cold rolled Cu/Al clad plate: experiment and simulation

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    Cu/Al corrugated clad plates were prepared by the novel corrugated cold roll bonding (CCRB) process to investigate the stress states, microstructures and mechanical behaviors of the corrugated clad plate adjacent to various corrugated interface positions by experimental and numerical simulation methods. The results show that the CCRB process induces multiple “cross shear” zones in the rolling deformation zone. This greatly accelerates the plastic deformation of Cu layer and significantly diminishes the deformation difference between Cu and Al dissimilar metals with a result of the reduced warpage amplitude. Also, the microstructure at different positions is obviously different due to the various stress states and deformations. Especially at positions III (trough) and IV (front waist), the elongated grains and fine equiaxed grains are formed under the severe plastic deformation and the shear stress. And the ultimate tensile strength achieves a maximum value of 209.25 MPa at position III (trough), and does the minimum value of 182.43 MPa at position II (back waist). The strength of the Cu/Al corrugated clad plate is affected by both the dislocation strengthening and grain boundary strengthening. When the plastic deformation is severe, the dislocation strengthening mechanism is dominant in Cu matrix, while the fine-grain strengthening mechanism in Al matrix

    Purification of Porcine Circovirus Type 2 Using an Affinity Chromatography Based on a Neutralizing Monoclonal Antibody against Viral Capsid Protein

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    Porcine circovirus type 2 (PCV2) is a DNA virus without an envelope. The viral particle is icosahedral and has a diameter of approximately 17 nm. In order to obtain the purified virus, a broad-spectrum monoclonal antibody 3A5 against PCV2 was coupled to CNBr-activated SepharoseTM 4B, and an affinity chromatography was established for PCV2 purification. A total of 6.5 mg of purified PCV2a/LG with 97% purity was obtained from 120 mL of the viral culture medium, and only PCV2 was detected by electron microscopy. No significant changes in the antigenic characteristics of the purified virus were detected by a capture enzyme-linked immunosorbent assay (ELISA). Furthermore, the titer of the purified PCV2 was 100 times higher than that of the unpurified virus. This affinity chromatography method was also used to purify PCV2b/LN590516 and PCV2d/SD446F16, and the purified viruses were detected by electron microscopy, capture ELISA, and virus titration, respectively. The results showed that these two strains can be successfully purified, but the yield is lower than that of the PCV2a strain. In addition, the purified virus could be used to study the viral adsorption and invasion of PK15 cells using indirect immunofluorescence assays. A large number of PCV2 signals were detected to transfer from the cellular surface to the periphery of the nucleus of the PK15 cells after 30 min of adsorption of the PCV2 to the PK15 cells. The affinity chromatography is a simple and convenient tool to obtain PCV2 with high purity. It could be applied for virus structure analysis, antibody preparation, and viral adsorption and invasion research

    Strengthening Effect of Extruded Mg-8Sn-2Zn-2Al Alloy: Influence of Micro and Nano-Size Mg2Sn Precipitates

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    In this study, Mg-8Sn-2Zn-2Al (TZA822) alloys with varying Mg2Sn contents prior to extrusion were obtained by different pre-treatments (without and with T4), and the strengthening response related to micro and nano-size Mg2Sn precipitates in the extruded TZA822 alloys was reported. The results showed that the morphology of nano-size Mg2Sn precipitates exhibits a significant change in basal plane from rod-like to spherical, owing to the decrement in the fraction of micro-size particles before extrusion. Meanwhile, the spherical Mg2Sn precipitates provided a much stronger strengthening effect than did the rod-like ones, which was ascribed to uniform dispersion and refinement of spherical precipitates to effectively hinder basal dislocation slip. As a consequence, the extruded TZA822 alloy with T4 showed a higher tensile yield strength (TYS) of 245 MPa, ultimate tensile strength (UTS) of 320 MPa and elongation (EL) of 26.5%, as well as a lower degree of yield asymmetry than their counterpart without T4. Detailed reasons for the strengthening effect were given and analyzed
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