The mechanical properties of refractory high-entropy alloys (RHEAs) are influenced by the types and concentrations of the constituent elements and significantly influenced by the precipitation behavior. In this study, the Al20Nb14Ti34Zr29Cr4 RHEA was designed to investigate the impact of precipitation on its microstructure and properties. The density of the alloy was only 5.53 g/cm3. Significant amounts of the Al3Zr5 phase and C14 Laves phase precipitated following prolonged annealing treatment. The evolution of the microstructure of the alloy was investigated through multi-directional forging at temperatures of 1000 degrees C and 1200 degrees C. High-temperature forging causes the dissolution of the Al3Zr5 phase, and greater dissolution occurs at elevated temperatures. Additionally, during high-temperature forging, dissolution and subsequent reprecipitation of the C14 Laves phase occur. Lower forging temperatures promote increased reprecipitation of the C14 Laves phase. The alloy forged at 1000 degrees C exhibited an exceptional yield strength of 1870.1 MPa, accompanied by a specific yield strength of 338.2 N center dot m/kg and a compressive limit deformation of 20.9 %. This remarkable performance can be attributed to the changes in the shape size and distribution of the precipitated phase during the forging process at 1000 degrees C, as well as the grain refinement caused by recrystallization. These factors work together to improve the strength and plasticity of the alloy.

Benefiting from the visible light emission behavior of the Sm3+ activator, Sm3+-incorporated inorganic phosphors have received considerable interest in solid-state lighting areas. Nevertheless, so far, highly efficient and heat-resistant optical materials activated with Sm3+ are scarce. In this work, a series of new orange-red-emitting phosphors K2SrP4O12 (KSPO):Sm3+,A+ (A+ = Li, Na, and K) were prepared by charge compensation strategy. Under 405 nm excitation, the phosphors exhibit strong orange-red emission. The incorporation of alkali metals A+ effectively compensates for the vacancy defects caused by the non-equivalent substitution of Sm3+ for Sr2+, improving the luminescent performance. In particular, the Na+-compensated phosphor exhibits a luminescence intensity 1.92 times greater than that of the uncompensated sample due to the fact that Na+ and Sr2+ have close ionic radii. It has demonstrated excellent internal quantum efficiency (37.1 %), high color purity (98.5 %), and high thermostability (94 %@423 K), significantly surpassing the majority of reported Sm3+-doped phosphors. In addition, a representative KSPO:0.03Sm3+,0.03Na+ phosphor is used to prepare W-LEDs, showing potential for solid-state lighting.

The family Potamanthidae is widely distributed across the Holarctic and Oriental regions, with nymphs often utilized as bioindicators for water pollution and human-induced environmental disturbances. However, limited mitochondrial genomes (mitogenomes) have been reported for this family. This study presents the first complete mitochondrial genome sequences of two Potamanthidae species, Potamanthus longitibius and Rhoenanthus youi. The mitogenome sizes were 15,430 bp and 15,232 bp, with A + T contents of 68.79% and 66.75%, respectively. The most abundant amino acids were phenylalanine (Phe), isoleucine (Ile), glycine (Gly), and alanine (Ala), with leucine (Leu2) showing the highest relative synonymous codon usage (RSCU) value. The analysis of tRNA secondary structures revealed high conservation among the tRNAs encoded on the H-strand. Phylogenetic reconstruction, incorporating 40 species from 13 families of Ephemeroptera, confirmed the monophyly of all the families and supported a sister group relationship between Potamanthidae and Ephemeridae. Additionally, the sequence previously identified as Rhoenanthus sp. JZ-2021 was reassigned to the genus Potamanthus. This study provides valuable insights into the evolutionary relationships within Potamanthidae and lays a foundation for future phylogenetic and taxonomic research.

Thymidine, as a crucial precursor of anti-AIDS drugs (e.g., zidovudine and stavudine), has wide application potential in the pharmaceutical industry. In this study, we introduced the thymidine biosynthesis pathway into the wild-type Escherichia coli MG1655 by systems metabolic engineering to improve the thymidine production in E. coli. Firstly, deoA, tdk, udp, rihA, rihB, and rihC were successively deleted to block the thymidine degradation pathway and salvage pathway in the wild-type E. coli MG1655. Then, the pyrimidine nucleoside operons from Bacillus subtilis F126 were introduced to enlarge the metabolic flux of the uridylic acid synthesis pathway. Finally, the expression of uridylate kinase, ribonucleoside diphosphate reductase, thymidine synthase, and 5'-nucleotidase in the thymidine biosynthesis pathway was optimized to enhance the metabolic flux from uridylic acid to thymidine. The engineered THY6-2 strain produced 11.10 g/L thymidine in a 5 L bioreactor with a yield of 0.04 g/g glucose and productivity of 0.23 g/(L·h). In this study, we constructed a strain that used glucose as the only carbon source for efficient production of thymidine and did not harbor plasmids, which provided a reference for the research on other pyrimidine nucleosides.

Thymidine, as a crucial precursor of anti-AIDS drugs (e.g., zidovudine and stavudine), has wide application potential in the pharmaceutical industry. In this study, we introduced the thymidine biosynthesis pathway into the wild-type

The production phenotype improvement of industrial microbes is extremely needed and challenging. Environ-mental factors optimization provides insightful ideas to trigger the superior production phenotype by activating potential genetic determiners. Here, phenotype-genotype mapping was used to dissect the betaine-triggered L-arginine overproduction mechanism and mine beneficial genes for further improving production phenotype. The comparative transcriptomic analysis revealed a novel role for betaine in modulating global gene transcription. Guided by this finding, 4 novel genes (cynX, cynT, pyrB, and rhaB) for L-arginine biosynthesis were identified via reverse engineering. Moreover, the rhaB deletion was demonstrated as a common metabolic engineering strategy to improve ATP pool in E. coli. By combinatorial genes manipulation, the L-arginine titer and yield increased by 17.9% and 28.9% in a 5-L bioreactor without betaine addition. This study revealed the molecular mechanism of gene transcription regulation by betaine and developed a superior L-arginine overproducer that does not require betaine.

数字化时下,传统纸质教材与电子网络教学资源融合形成的新形态教材已逐渐成为民办高校教材建设的新趋势.新形态教材建设包括纸质内容的修订与更新,精品课程资源的融合、MOOC等在线开放课程的使用以及移动终端资源共享等多项内容.以《报关单证》课程为例,该课程内容主要分为两部分,一是报关实务,二是单证实务,需要用两本教材分别教学.在该课程的教材建设过程中,需充分重视学生对数字化教材的意见,在未来开发支持多种智能终端的学习APP,建立报关单证课程的网络资源库,结合数字资源在不同终端运行的兼容性和优化应用模式,构建出适合民办高校新形态教材建设的有效实施路径.

平台经济是以数字化技术为基础,实体和虚拟交易平台为支撑,通过智能网络衔接而组成的相关经济单元活动.平台经济衔接了电商、 社交、 物流等多种商业领域的供求关系,其中物流是凝聚资源并将上下游组织围绕平台重构形成新零售体系的关键.物流新业态的主要研究内容聚焦在企业整合各自拥有的租赁、 自建、外包等资源优势以提供全域全时的综合服务方案,并向数字化、 智能化新服务领域转型等方面;新的物流业态需要在与商流精准对接的基础上降低成本、 优化现有运营模式,突出实现平台经济中"人、 货、 场"等关键要素的高度融合.据此可以在研究传统物流网络升级的同时转向即时、 生鲜物流等新热点,寻求利用智慧元素提升实际业务的响应速度与匹配效率,在传统自建物流体系基础上研究模块外包和建设区域直控领域内的中心仓至前置仓小范围供应链,以期在未来能够形成通过明仓暗仓、 生鲜冷链、 智慧物流引导下的多元化生态交易闭环系统.

环保产业的严格性、长期性趋势已初步形成,具有巨大的市场空间.根据我国环保产业发展新情况,以环保产业链发展现状为基础,分析库兹涅茨曲线与环保投入曲线的关系以明确行业发展的变化趋势,通过大气网格化管理、垃圾处理与废电拆解、河长制治理与政府和社会资本合作(PPP)模式等方法的应用,对环境监测、固废分类、废水处理、土壤修复等相关子行业开展具体研究,以此测算不同子行业的市场空间、细化运营模式,以期从治理成本、市场格局、环境服务等综合视角为整个环保产业发展提供参考.

伴随经济的发展,经济、社会、环境的协调发展成为全球各国关注的焦点,人类可持续发展成为经济发展的目标,本文在可持续发展背景下探索了中国装备制造业的发展问题,主要分析了环境规制影响中国装备制造业的产业结构升级现状问题,从直接和间接的角度分析了其影响路径,期望为中国装备制造业的产业结构升级提供理论借鉴.

本文以江苏农村电商发展为研究对象,将关注的视角放在了电商轻资产与重资产运营模式方面,以生鲜为例,围绕精准扶贫视角下江苏农村电商轻资产与重资产运营模式展开探究.首先,对精准扶贫、轻资产与重资产等相关概念进行了解析;其次,结合现阶段江苏省农村生鲜电商整体发展情况,对其轻资产与重资产运营模式进行了对比分析;最后,详细介绍了精准扶贫视角下江苏省农村电商轻资产与重资产运营模式优化策略.希望能够在以下研究的基础上对进一步促进江苏省农村电商轻资产与重资产优化调配具有一定的借鉴意义,以此来助推江苏生鲜电商实现可持续健康稳固发展.

"互联网+"时代下消费者的购物喜好和习惯发生了巨大转变,电商爆发式增长对传统客户的分流明显;实体商业的经营成本和费用也在逐年递增,线下门店扩张速度放缓,新店铺的培育与成长周期变长,这些都使得客户流量的变现能力被削弱,增长节奏被打破.在此背景下,实体零售业需要在主营业务端重新实施新生态布局,突出商业模式的演进和商业元素的转换.在O2O(Online To Offline,线上到线下)融合趋势下,如何做到线上线下的深度统一,将电商便捷与价格优势和实体零售的切实体验与个性服务相结合,是未来需要准确考虑和选择的方向.在趋势上,数字化新零售将突破传统的禁锢,把商流、 信息流、 资金流与服务、 体验和物流加以整合,使商业实体在产业链、 生态体系等方面能够切合市场需要进行转型升级,可以预见大数据下的O2O全渠道运营将是未来新零售商业细化和再创新的发展方向.

出口信用险是出口国政府为外贸企业提供的由于进口国政治风险(包括战争、外汇管制、进口管制和延期付款等)和进口商商业风险(例如破产、拖欠和拒收等)导致收汇损失的政策性险种.如果卖家因为上述原因不能如期收款,可以由保险公司先行赔付,至于保险公司如何向买家追偿以及能否追回货款,与出口商无关.在我国承担这一重要政策性扶持角色的是中国出口信用保险公司(简称中信保).也正因为出口信用险保障的是卖方利益,所以有些不法分子就利用中信保的资信对出口商巧妙设局,实施真实的业务诈骗,这对我国出口商提出了非常有价值的警示和针对性的思考.

Based on the energy consumption data of the logistics industry in 30 provinces and cities in China, this paper uses the carbon emission accounting method of IPCC to estimate the total carbon emissions of the logistics industry in China from 2010 to 2019, and introduces the carbon emission Theil index. The Logarithmic Mean Divisia Index (LMDI) model is used to measure the regional differences in carbon emissions of China's logistics industry and decompose the influencing factors. The research results show that the total carbon emissions of China's logistics industry have increased significantly, and the total carbon emissions and growth rates of the eastern region are significantly higher than those of the central and western regions. On the whole, the inter-provincial differences in carbon emissions of China's logistics industry have not changed substantially and have shown a downward trend. Intra-regional differences are the main reason for the overall difference in carbon emissions in China's logistics industry, and inter-regional differences have little impact on the overall difference. Among the three major regions, the eastern region has the largest inter-provincial carbon emissions difference, followed closely by the central region, with the western region having the smallest difference. Furthermore, the difference in carbon emissions between the eastern, central, and western regions is expanding, the results of the LMDI model show that the economic development effect is the most important positive effect of the logistics industry's carbon emissions in terms of the national average. The population scale effect is second, and the energy intensity effect is the main negative effect, followed by the energy structure effect. In terms of regional differences, the energy intensity effect is the most obvious in the eastern region, and the population scale effect has a relatively greater impact on the western region. The effect of economic development on the eastern and western regions is higher than in the central region.

Large intergenic spacers and tRNA gene duplications have been reported in several insect groups, although little is known about mitogenomes of mayflies. Here, we determined complete mitogenomes of ten heptageniid species and systemically analyzed their mitogenomic features. Both a conserved intergenic spacer (IGS) and trnM duplication were detected in those mitogenomes. The IGS, which was observed in heptageniids, could be further folded into a stable stem–loop structure. The tRNA gene duplication was found in almost all analyzed mitogenomes, and a unique gene block trnI-trnM-trnQ-trnM-ND2 was also discovered. Our analysis demonstrates that the heptageniid gene arrangement pattern can be explained by the tandem duplication-random loss (TDRL) model. Phylogenetic analyses using both Bayesian inference (BI) and maximum likelihood (ML) methods based on the nucleotide and amino acid sequence data recovered the genus Epeorus as monophyletic with strong support. Our results provide a better understanding of mitogenomic evolution in Heptageniidae, as well as novel molecular markers for species identification of mayflies.

The nearly complete mitochondrial genome (mitogenome) ofLethe confusewas sequenced and analyzed. This mitogenome is 14,945 bp in size and encodes 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes. The most common start codon is ATN (ATA, ATG, and ATT), and the most common termination codon is TAA. In addition, three PCGs have incomplete termination codon T. The overall nucleotide composition is 38.0% of A, 7.8% of G, 42.4% of T, and 11.8% of C. The data will increase the basic information of Satyrinae phylogenetic research and can help to better understand the phylogenetic status ofL. confusein Nymphalidae.

The recent hype in online purchasing has skyrocketed the importance of the electronic commerce (e-commerce) industry. One of the core segments of this industry is business-to-consumer (B2C) where businesses use their websites to sell products and services directly to consumers. Thus, it must be taken care of that B2C websites are designed in a way which can build a trustworthy and long-term relationship between businesses and consumers. Thus, this study assesses and prioritizes factors for designing a successful B2C e-commerce website. The study employs multi-criteria decision making (MCDM), and to minimize any ambiguity and greyness in the decision-making, it integrates fuzzy and grey respectively with the Analytical Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) to form FAHP and TOPSIS-Grey. Initially, the study conducts a thorough literature survey to screen important factors reported in past studies. Five main factors and nineteen sub-factors were selected for further prioritization. Later, FAHP prioritized factors based on their importance. Finally, based on the FAHP results, TOPSIS-Grey ranked five alternatives (e-commerce websites). FAHP revealed “service quality” as the most successful website designing factor, while TOPSIS-Grey reported “Website-3” as the most successful website, having incorporated the factors required to design a successful website.