Search

Summary: The peduncle vascular system of maize is critical for the transport of photosynthetic products, nutrients, and water from the roots and leaves to the ear. Accordingly, it positively affects the grain yield. However, the genetic basis of peduncle vascular bundle (PVB)‐related traits in maize remains unknown. Thus, 15 PVB‐related traits of 386 maize inbred lines were investigated at three locations (Yongcheng, 17YC; Kaifeng, 20KF; and Yuanyang, 20YY). The repeatability for the 15 traits ranged from 35.53% to 92.13%. A genome‐wide association study was performed and 69 non‐redundant quantitative trait loci (QTL) were detected, including 9, 41, and 27 QTL identified at 17YC, 20KF, and 20YY, respectively. These QTL jointly explained 4.72% (SLL) to 37.30% (NSVB) of the phenotypic variation. Eight QTL were associated with the same trait at two locations. Furthermore, four pleiotropic QTL were identified. Moreover, one QTL (qPVB44), associated with NSVB_20KF, was co‐localized with a previously reported locus related to kernel width, implying qPVB44 may affect the kernel width by modulating the number of small vascular bundles. Examinations of the 69 QTL identified 348 candidate genes that were classified in five groups. Additionally, 26 known VB‐related homologous genes (e.g. VLN2, KNOX1, and UGT72B3) were detected in 20 of the 69 QTL. A comparison of the NSVB between a Zmvln2 EMS mutant and its wild type elucidated the function of the candidate gene ZmVLN2. These results are important for clarifying the genetic basis of PVB‐related traits and may be useful for breeding new high‐yielding maize cultivars. [ABSTRACT FROM AUTHOR]

In this paper, by testing the evolution of the physically bound water using the low-field nuclear magnetic resonance (LF-NMR) technology, the hydration process of cement paste with nano-CaCO3 (NC) and superabsorbent polymer (SAP) at early age is investigated. Results indicate that the hydration process can be divided into four periods according to the zero points of the second-order differential hydration curve: initial period, acceleration period, deceleration period, and steady period. Firstly, with the increase in the water to cement ratio, the starting time of the hydration period is delayed, and the duration becomes longer. Secondly, the addition of NC leads to the speedy arrival of each period and shortens the duration of each period in the hydration process, and the optimal NC content is 1.5%. Thirdly, with the increase in SAP content, the starting time of the hydration period is delayed and the duration becomes longer. Finally, based on the experimental results and the existing hydration model, the modified hydration model considering the content of NC and SAP is proposed. [ABSTRACT FROM AUTHOR]

This article proposes a novel dual-three-phase high-power high-speed permanent magnet assisted synchronous reluctance starter generator (PMaSynR SG) for aviation application, which has the characteristics of high efficiency, high power density, high reliability, and excellent antishort-circuit ability. The proposed PMaSynR SG can obtain higher efficiency and power density by embedding permanent magnet in the rotor topology compared with the synchronous reluctance generator, and has better antishort-circuit ability compared with the permanent magnet synchronous starter-generator. Moreover, design of dual-three-phase winding is adopted, which not only reduces the phase current, but also improves the reliability. In this article, the topological structure, characteristics and principle of PMaSynR SG are systematically studied at first. Second, a simplified dq-axis equivalent magnetic circuit model is established, and the expressions of dq-axis inductance and permanent magnet flux linkage are derived on the basis of the basic parameter selection. Then, combined with parameter sensitivity analysis, the influence law of rotor structural parameters on antishort-circuit ability and electromagnetic performance is revealed. Finally, a 40 kW 24 000 r/min PMaSynR SG is designed and manufactured. The simulation and experimental results show that the proposed PMaSynR SG has excellent electromagnetic performance with the power density of 3.1 kW/kg and the efficiency of 94%, while the short-circuit current is only 59% of its rated value. [ABSTRACT FROM AUTHOR]

Dense corundum-mullite brick for blast furnace ceramic pad was prepared using white fused corundum and tabular corundum as aggregates, andalusite fine powder, sillimanite fine powder, zircon sand powder and Guangxi soil as the matrix, and phosphate as the binder, introducing different amounts of α-alumina micropowder, tabular corundum fine powder and fused corundum powder. The properties of the prepared brick were studied. The results show that, the brick with 10 mass % of tabular corundum fine powder fired at 1 560 ℃ for 3 h in a tunnel kiln has the bulk density of 3.08 g · cm-3, the apparent porosity of 13.2%, the cold compressive strength of 178 MPa, the molten iron corrosion rate of 0.6%, the slag corrosion rate of 6.4%, the alkali resistance strength decreasing rate of 7.5%, and the thermal shock resistance of 32 cycles, which is both dense and of good thermal shock resistance. The slag resistance simulation test was performed, which proved that the prepared corundum-mullite brick is better than those currently supplied in the market. [ABSTRACT FROM AUTHOR]

• Effects of zeolite and CEA on mechanical properties of concrete are investigated. • Effects of zeolite and CEA on IRH of concrete are studied. • Effects of zeolite and CEA on autogenous deformation of concrete are evaluated. • Synergistic mechanism of zeolite and CEA on AS mitigation of concrete is analysed. High-performance concrete (HPC) is prone to cracking at an early age due to the large autogenous shrinkage (AS), which severely weakens the durability of the concrete structure. CaO-based expansive agent (CEA) is widely utilized to compensate for the AS of HPC, but CEA cannot achieve its potential expansion in HPC due to a low water to binder ratio, resulting in an incomplete hydration, and a sharp and substantial retraction after initial expansion. Pre-soaked zeolite can be introduced as internal curing (IC) agent to reduce the AS of HPC owing to the IC water released from zeolite. According to the AS-reduction mechanism of CEA and zeolite, a synergistic mechanism can be achieved by the combination use of CEA and zeolite in HPC. However, a comprehensive understanding of the effects of the combination use of zeolite and CEA on the mechanical properties and autogenous deformation of concrete is still lacking. Therefore, the influence of zeolite and CEA addition on mechanical properties and autogenous deformation were investigated experimentally. The investigation results showed that the zeolite addition weakened the mechanical properties of concrete while the CEA addition had the opposite effect. The internal relative humidity in concrete was significantly improved with zeolite and CEA incorporation. The IC water released from zeolite could not only enhance the expansion efficiency at an early age but also greatly reduce the retraction at the later age. The results exhibited an obvious synergistic mechanism with the combination use of zeolite and CEA on AS mitigation, which is of great benefit in AS-induced cracking control. [ABSTRACT FROM AUTHOR]

The effects of nano-SiO2 and superabsorbent polymer on the hydration process of early-age cement paste are investigated through the physically bound water evolution test by means of the low-field nuclear magnetic resonance technology. The test results show that the hydration process can be characterized by four-stage patterns based on the zero points of the second-order differential hydration curve, i.e., the initial, accelerated, decelerated, and steady periods. The beginning time of each stage is postponed and the hydration duration is prolonged with an increasing water to cement ratio. The beginning time of each stage and the hydration duration are shortened with an increasing content of nano-SiO2. And the beginning time of each stage and the hydration duration are prolonged with an increasing content of superabsorbent polymer. Based on the test data and the Avrami–Erofeev model, a modified hydration model taking the influence of nano-SiO2 and SAP into account is proposed, and the predicted results are consistent with the test results. [ABSTRACT FROM AUTHOR]

Internode length is one of the decisive factors affecting plant height (PH) and ear height (EH), which are closely associated with the lodging resistance, biomass and grain yield of maize. miRNAs, currently recognized as important transcriptional/ post-transcriptional regulators, play an essential role in plant growth and development. However, their roles in developing internodes under maize ears remain unclear. To identify the roles of miRNAs and their targets in the development of internodes under maize ears, six miRNA and two degradome libraries were constructed using the 7th, 8th and 9th internodes of two inbred lines, ‘Xun928’ and ‘Xun9058’, which had significantly different internode lengths. A total of 45 and 54 miRNAs showed significant changes for each pairwise comparison among the 7th, 8th and 9th internodes of ‘Xun9058’ and ‘Xun928’, respectively. The expression of 31 miRNAs showed significant changes were common to the corresponding comparison groups of the 7th, 8th and 9th internodes of ‘Xun9058’ and ‘Xun928’. For the corresponding internodes of ‘Xun9058’ and ‘Xun928’, compared with the expression of miRNAs in the 7th, 8th and 9th internodes of ‘Xun928’, the numbers of up-regulated and down-regulated miRNAs were 11 and 36 in the 7th internode, 9 and 45 in the 8th internode, and 9 and 25 in the 9th internode of ‘Xun9058’, respectively. Moreover, 10 miRNA families containing 45 members showed significant changes at least in two internodes of ‘Xun928’ by comparing with the corresponding internodes of ‘Xun9058’. Based on the sequencing data, 20 miRNAs related to hormone signaling among the candidates, belonging to five conserved miRNA families, were selected for expression profiling using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The five miRNA families, zma-miR160, zma-miR167, zma-miR164, zma-miR169 and zma-miR393, targeted the genes encoding auxin response factor, N-acetylcysteine domain containing protein, nuclear transcription factor Y and auxin signaling F-BOX 2 through degradome sequencing. The miRNAs might regulate their targets to respond to hormone signaling, thereby regulating the internode elongation and development under maize ear. These results provide valuable reference for understanding the possible regulation mechanism of the ILs under the ear. [ABSTRACT FROM AUTHOR]