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• The Fe-containing phase selection can be controlled by optimizing the Mg/Si ratio. • The good ductility of Mg-riched alloys correlates with the fine α-AlFeSi phase. • Mg-riched alloys exhibit a stable high yield strength during thermal exposure. • The superior thermal stability of Mg-riched alloys is related to the L phase. • The reason for the high thermal resistance of the L phase is discussed. Achieving high thermal stability in the 6xxx series alloys remains a challenging task, which limits their engineering application. Herein, Al-Mg-Si-Cu alloys with various Mg/Si ratios (0.5, 1, 2, and 4) were fabricated by twin-roll casting (TRC), and the microstructure evolution and mechanical properties during long-term thermal exposure of 150 °C/1000 h were studied. The results disclosed that alloys with a high Mg/Si ratio exhibited better thermal stability. The alloys with the Mg/Si ratio of 2 (Mg/Si∼2) achieved a stable high yield strength of ∼330 MPa and meanwhile maintained a satisfactory fracture elongation (> 10 %) throughout the thermal exposure process. This excellent thermal stability can be attributed to the microstructure consisting of high-density L phases and fine α-AlFeSi phases, which was related to the optimized Mg/Si ratio. Specifically, L phases were dominated in peak-aged Mg/Si∼2 alloys, while the counterparts in alloys with the Mg/Si ratio of 1 (Mg/Si∼1) were β'' and Q' phases. During the thermal exposure process, the L phases remained stable without coarsening, which was mainly due to the high coherence and low interfacial energy of the L -matrix interface. Meanwhile, the main Fe-containing phases in Mg/Si∼2 and Mg/Si∼1 alloys were fine near-spheroidal α-AlFeSi and large-size needle-like β-AlFeSi, respectively, which lead to a better ductility of Mg/Si∼2 alloys. This work may provide a strategy for the preparation of 6xxx series alloys with high thermal stability. [ABSTRACT FROM AUTHOR]

• In 6xxx series alloys, the alleviation degree of microsegregation is distinct for different alloying elements, sequenced as Mg > Si > Fe, when cooling rate increases from 5 K/s to 128 K/s. • The different solute elements impose its own response of partitioning to cooling rate, denoted as R k. A theoretical equation of R k is proposed, which is a function of equilibrium partitioning coefficient, crystal growth rate, and diffusion coefficient of solute in liquid. • A broad range of R k values of other common solute elements in Al alloys are evaluated, delivering a handy tool to describe microsegregation behavior. It is commonly recognized that the cooling rate has a substantial effect on solute partitioning and its resultant microsegregation during solidification. The classical dendrite tip undercooling theory clarifies the mitigation of microsegregation by increasing the cooling rate. However, most of the studies focused on binary alloys, leaving an open question as to whether the microsegregation of different solutes in a multi-component alloy system exhibits a relieving degree similar to increasing cooling rate. Taking a widely used 6022-type Al alloy (Al-0.76Mg-0.93Si-0.2Fe) as a model alloy, the current study reveals that the microsegregation of Mg gets alleviated to the greatest extent, followed by those of Si and Fe when the cooling rate increases from 5 to 128 K/s. This phenomenon is attributed to the solute-based difference in response to partitioning to cooling rate (denoted as R k). We propose a theoretical equation to quantify R k , and the R k values of solute Mg, Si, and Fe successfully explain the rank of solute partitioning in experiments. Furthermore, a broad range of R k values of other commonly used alloying elements in Al alloys were calculated and ranked, delivering a handy tool to predict the microsegregation behavior and solubility of different solute elements upon sub-rapid solidification, which is consistent with experimental observation. This framework can also be extended to other multi-component alloy systems. [ABSTRACT FROM AUTHOR]

This study empirically examines the impact of Domestic Investment (DI) and Foreign Direct Investment (FDI) on the economic development of Cameroon from 1990 to 2018. The four factors investigated include financial development, institution, infrastructure, and social capital. Both the dynamic panel estimate and standing panel lapse methods were used to evaluate the connection between DI and FDI concerning the economic development based on the factors enumerated. The results show that DI has a positive influence on and correlates with the growth of the economy. In addition, it indicated that there is an improvement in the financial progress when FDI is on the increase. Moreover, this study indicates that the increase in the institutions, human capital, and the monetary system improves the economic development of the country. It can be inferred from the results that Cameroon had a significant increase in her infrastructures and school enrolment from 2001 to date because of the increase in DI and FDI. The results show that FDI negatively affects some social capital of the Cameroon people such as the displacement of schools and markets, which is consistent with previous studies and results from the literature reviewed.

Al-Mg-Si (AA6xxx) series alloys have been used widely in automotive industry for lightweight purpose. This work focuses on developing a short process for manufacturing Al-0.5Mg-1.3Si (wt.%) alloy sheets with good mechanical properties. Hereinto, a preparation route without homogenization was proposed on the basis of sub-rapid solidification (SRS) technique. The sample under SRS has fine microstructure and higher average partition coefficients of solute atoms, leading to weaker microsegregation owing to the higher cooling rate (160 °C/s) than conventional solidification (CS, 30 °C/s). Besides, Mg atoms tend to be trapped in Al matrix under SRS, inducing suppression of Mg 2 Si, and promoting generation of AlFeSi phase. After being solution heat treated (T4 state), samples following the SRS route have lower yield strength compared with that by CS route, indicating better formability in SRS sample. After undergoing pre-strain and artificial aging (T6 state), the SRS samples have comparable yield strength to CS samples, satisfying the service requirements. This work provides technological support to industrially manufacture high performance AA6xxx series alloys with competitive advantage by a novel, short and low-cost process, and open a door for the further development of twin-roll casting based on SRS technique in industries. [ABSTRACT FROM AUTHOR]

The effect of trace cerium on microstructures and mechanical properties of 690MPa steel plates used for engineering machinery was researched by the comparative analysis of the microstructures, inclusions, and comprehensive mechanical properties of the steel plates after rolled, quenched and tempered. The result shows that trace cerium can improve the yield strength, tensile strength of rolled and quenched steel plates, and low temperature impact toughness of the tempered steel plate significantly, but has little effect on the yield strength and tensile strength of the tempered steel plates. The cerium-bearing steel has finer grain size, less inclusion contents and more spheroidal than that of cerium-free steel. The yield strength of 10 megapascal, the tensile strength of 20 megapascal for rolled plates and the yield strength of 130 megapascal, the tensile strength of 100 megapascal for quenched plates was improved by the addition of cerium. In spite of this, the cerium has little effect on the yield and tensile strength but improved about 50 Joule impact energy values under-40 centigrade degree temperature after the plate was tempered at the temperature of 620 centigrade degree. It has the same rules of the plates tempered at the temperature of 580 centigrade degree.

This paper firstly analyzes the mechanism of transmission line and transformer loss and illustrates the equivalent model and calculating method. Then creates a simple three-node model and discusses the main factors which affect the grid loss with adequate formula. At last, we draw a concise conclusion that there are several factors affecting grid loss. The main factors are the location of wind power access, the active power flow of transmission lines, the active power output of wind farms and the voltage level of wind power access.

This paper evaluated the energy and emergy characters and indicators of the protected grape production system in the five major producing areas in China based on the emergy analysis. The research results indicate that the total emergy input in the Northwest region is the largest. The protected cultivation in all the five regions is heavily dependent on the purchased resource and nonrenewable resource emergy. The Southwest region is found to have the lowest environmental pressure and the highest sustainability.

Due to business expansion and increased market competition, Tianfu thermoelectric original electric gas marketing system can no longer meet the needs of enterprise development which lead to information islands. In response to these issues, based on the business needs, this paper constructed a marketing network management system platform integrated with electricity, heat and gas for the thermal power enterprises. This system includes: 1) Establishment of enterprise data center and centralized storage of the business system data. 2) Establishment of enterprise portal system for achievement of single sign-on. 3) Establishment of power energy information collection and management system of the power purchase, supply and sale departments. 4) Establishment of "all-in-one-card" system including electricity, heat and gas IC card. 5) Creation of a marketing analysis and strategic decision-making system. The system platform can offer efficient and reliable basis for business processing capabilities to electricity, heat, and gas marketing business.

A japonica restorer line (named m119) with extremely high protein content was bred successfully, whose protein content (wet base) reached 13.30%±0.19% in brown rice. SDS-PAGE analysis showed that the proportion of glutelin to total protein content increased to 71.77% in m119 compared with CK. The fracture of m119 grain was rough compared with CK, which might bring about negative influence to cooking and eating quality. However, there was no significant difference of endosperm cell in size, shape and distribution compared with CK. The increase of protein content in brown rice was neither proportion nor synchronization; The axis of japonica rice grain was nearly at the center and close to the ventral part of the grain fracture observed by confocal laser scanning microscopy, which was associated with the distribution of vascular bundles transporting nutrition to the grain. The proportion of smooth to rough surface in soaked grain fracture had certain correlation with protein content and cooking and eating quality.

Rosmarinic acid, a polyphenol-containing hydroxy acid, is believed to have many activities, such as anti-oxidation, anti-inflammatory, immune regulation, anti-thrombosis generation, anti-baterial, anti-virus and anti-depressants. It is used commercially for food preservation. Here we report that rosmarinic acid extended the lifespan of the model organism Caenorhabditis elegans (C. elegans) under normal culture conditions (25°C) and under thermal stress (35°C). C. elegans dieted rosmarinic acid with final concentration 50mg / L and 100mg / L under two kind of conditions were shown to have extended lifespan compared to the control without rosmarinic acid uptake. Furthermore, the rosmarinic acid with final concentration 50mg/L had more obvious longevity-extending effect. The precise mechanism (s) responsible for this remains to be identified. To study the anti-senescence molecular mechanism of rosmarinic acid, semi-quantitative RT-PCR was used to analyze the expression of aging-associated genes such as daf-16 and heat shock protein 16.2 (hsp-16.2). As a result, the expression of aging-associated genes was up-regulated. This study suggested that rosmarinic acid significantly extends the lifespan of C. elegans through up-regulating some genes' expression such as daf-16 and hsp-16.2 which will provide important reference for antiaging research of rosmarinic acid.