Search

IntroductionLocalized nitrogen (N) supply affects rice N uptake by influencing N release, and few studies have examined the effects of root zone N distribution and root growth on rice yield under localized N supply (LNS).MethodsA two-year field experiment was conducted with six treatments: no N application, farmers’ fertilizer practice (FFP), and four LNS treatments, including two types of N fertilizer with urea (U) and controlled release urea (CRU) were mechanically side deep fertilized (SDF) or root zone fertilized (RZF) at 10 cm soil depth (US, UR, CRUS and CRUR treatments, respectively).ResultsCompared with FFP, the dry matter accumulation, N uptake, and yield of LNS increased by 27%, 21%, and 17%, respectively. For N fertilizer type, compared with U, the NH4+-N concentration, total root surface area, volume, average diameter, and root biomass of CRU were significantly increased by 50%, 43%, 53%, and 23%, respectively, which resulted in a significant increase in yield by 12%. Regarding the N application methods, the total surface area, volume, average diameter, and root biomass of SDF were significantly increased by 32%, 24%, 10%, and 25% compared with RZF, respectively. However, the NH4+-N under RZF was more stable and lasted longer, with a significant increase in NH4+-N concentration of 21% compared to the SDF. Moreover, CRUR increased yield, N agronomic use efficiency, and gross return by 3.15%, 5.62%, and 2.81%, respectively, compared to CRUS.ConclusionCRU should be selected as the recommended N fertilizer types, and the combination of CRU and RZF was the most effective choice for rice production.

Co–Cr–Fe–Ni–Ta eutectic multi-principal element alloys (MPEAs) demonstrate great potential to replace structural alloys in engineering applications. However, the cost of these alloys is high due to the usage of a number of precious metals. To decrease the cost, the present work developed a set of novel Fe55Cr15Ni30−xTax (x = 0, 5, 8, 10 and 15 at.%) eutectic MPEAs and the effect of Ta on microstructure and compressive mechanical properties were investigated for the first time. As the Ta content increases, the microstructure changes from a single-phase FCC solid solution (x = 0) to hypoeutectic microstructure (x = 6), then to eutectic microstructure (x = 8), and eventually to hypereutectic microstructure (x = 10 and 15). The yield strength and the hardness increase at the expense of ductility reduction with increasing Ta content. The strengthening mechanism of this alloy system is mainly second-phase strengthening caused by Laves phase and grain boundary strengthening produced by eutectic interface, supplemented by solid solution strengthening. The Fe55Cr15Ni22Ta8 and Fe55Cr15Ni20Ta10 alloys present the excellent comprehensive mechanical properties. The yield strength, fracture strength and fracture strain of the former are 838 MPa, 1994 MPa and 45.1%, respectively. The yield strength, fracture strength and fracture strain of the latter are 1029 MPa, 1956 MPa and 43.0%, respectively. The phase formation of Fe55Cr15Ni30−xTax alloys can be predicted by Md criterion. When Md ≥ 0.89, the alloys consist of FCC phase and Laves phase. Otherwise, the alloys consist of FCC single phase.

Excessive nitrogen application is a common phenomenon in rice production in China, which will lead to a low nitrogen utilization rate and increase farmers’ production costs. In Jingzhou, Hubei Province, for two consecutive years (2021, 2022), rice was planted with nursery-box total fertilization (NBTF) technology to provide technical support for rice seedling box contact fertilization technology. The results showed that, compared with the conventional treatment, the seedling emergence rate decreased by 7.70–11.87%, but the seedling quality significantly improved and the plant height significantly increased by 4.38–6.06% in the full-heading stage after the aforementioned treatments. The leaf area index significantly increased by 16.75–34.55%, 10.04–19.30%, and 12.13–18.60% in the tiller, booting, and full-heading stages, respectively, whereas the photosynthetic rate significantly increased by 3.80–5.25% in the booting stage. The rice yield under the 50% CRU and 50% CRU + S treatments was the same as that under the FFP treatment. The rice yield under 50% CRU + BT and 50% CRU + BT + S treatments was 7.50–10.61% higher than that under the FFP treatment; nitrogen partial factor productivity increased by 96.15–123.63%. NBTF combined with Boxingtanzhuang (in Chinese) seedling trays showed an increase in yield, whereas normal seedling trays showed a stable yield. It is suggested that the seedling tray and fertilizer should be specialized in the rice seedling box, and the height of the seedling tray should be increased by 3–5 cm. At the same time, special controlled-release urea should be selected to ensure less N release before emergence and improve the seedling emergence rate so as to popularize NBTF technology in a large area.

IntroductionThis study aimed to provide the theoretical basis for formulating scientific and reasonable on-farm nitrogen (N) management measures and efficient strategic fertilization to understand the effects of localized N supply (LNS) and N fertilizer variety coupling on N transport and soil N balance in rice fields.MethodsA 2-year field experiment (2020 and 2021) was conducted in Jingzhou, Hubei Province, which included the following six treatments: no N application (CK), farmers' fertilizer practice (FFP), and four LNS treatments, including two N application methods including mechanical side-deep fertilization (M) and root-zone fertilization (R), two N fertilizer types with urea (U), and controlled-release urea (CRU).ResultsCompared with FFP, LNS increased the N apparent translocation level from stems, sheathes, and leaves (TNT) and N uptake by 10.70–50.59% and 11.28–29.71%, respectively. In LNS, the levels of nitrite reductase (NR), glutamine synthetase (GS), and glutamate synthase (GOGAT) under R increased by 13.81, 9.56, and 15.59%, respectively, compared with those under M, resulting in a significant increase in TNT by 8.58% and N uptake by 1.87%. Regarding the N fertilizer type, CRU significantly increased chlorophyll content by 7.27%, superoxide dismutase (SOD) and catalase (CAT) by 14.78 and 29.95% (p < 0.05), and NR, GS, and GOGAT by 44.41, 16.12, and 28.41% (p < 0.05), respectively, compared with that in U, which contributed to N absorption and transport. Moreover, CRUR significantly decreased N apparent loss by 50.04% compared with CRUM (p < 0.05).DiscussionConsidering the risk of soil N leaching and environmental protection, R should be selected as the recommended fertilization method. The combination of CRU and R is the most effective fertilization approach.

Cyclic stability of elastocaloric effect is the key factor that restricts the elastocaloric cooling application of Ni–Mn–Sn alloys fabricated by the conventional melting technique. Element doping is an effective way to enhance the performance of materials. In this work, the effect of Tb substitution for Ni on martensitic transformation (MT) temperature, microstructure, mechanical properties and cyclic stability of elastocaloric effect in the Ni43.5–xTbxMn45.5Sn11 (x = 0, 0.6, 1.2 and 1.8) magnetic shape memory alloys has been investigated. MT temperatures increase with increasing x from 0 to 1.2 and then decrease with further increasing x to 1.8. The substitution of Tb for Ni introduces γ phase (Tb-rich second phase in Tb-doping alloys). The volume fraction of γ phase increases with increasing Tb content and thus the mechanical properties and the cyclic stability of elastocaloric effect increase with the increase of Tb content. Among these alloys, Ni42.3Tb1.2Mn45.5Sn11 alloy shows a large adiabatic temperature change of 10.0 K induced by applying the uniaxial stress of 550 MPa. In addition, a constant temperature change of 6.5 K shows no apparent degradation under the compressive stress of 350 MPa during 1000 cycles for this alloy. The excellent elastocaloric properties make this alloy a promising candidate for the room-temperature elastocaloric cooling application. The underlying mechanism of the enhanced cyclability of elastocaloric effect and mechanical properties is also revealed.

ObjectiveTo examine the correlations between fundamental movement skills and health-related fitness elements (cardiopulmonary function, flexibility, body composition, muscle strength and endurance) in children and adolescents and investigate the evaluation methods and tools of fundamental movement skills and health-related fitness.MethodsSix electronic databases (Web of Science, PubMed, ProQuest, Scopus, EBSCO and CNKI) were searched, and the research literature on the correlation between children's and adolescents' fundamental movement skills and health-related fitness published since 2002 was collected. The guidelines of the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement and the Consolidated Standards of Reporting Trials (CONSORT) statement were used to evaluate the quality of the literature, and the sources, samples, measurement methods, main results and statistical data of the study were analyzed, summarized and discussed.ResultsAfter applying the inclusion and exclusion criteria, 49 studies were included. There were 13 tools for evaluating fundamental movement skills and 4 tools for evaluating comprehensive health-related fitness in the included literature. Sufficient research evidence supports a significant positive correlation between fundamental movement skills and cardiopulmonary function (10, 100%) and muscle strength and endurance (12, 100%), and most studies support the positive correlation between fundamental movement skills and flexibility (4, 66.7%), and the significant negative correlation between fundamental movement skills and body composition (29, 67.4%). Studies used skinfold, AF%, BF%, FM, and FFMI as evaluation methods. They showed a consistently significant negative correlation between body composition and fundamental movement skills (9, 100%), while BMI or waist circumference as evaluation methods showed no consistent significant negative correlation result (20, 58.8%). Moreover, in the sub-item evaluation of fundamental movement skills, object manipulation, locomotor and balance skills were all significantly and positively correlated with cardiopulmonary function and muscle strength and endurance. In contrast, locomotor skills were more closely related to body composition than object manipulation skills.ConclusionA significant correlation exists between children's and adolescents' fundamental movement skills and health-related fitness elements.

High-temperature shape memory alloys (HTSMAs) show enormous potential for applications as energy conversion devices, actuators and sensors in automotive, aerospace, and energy exploration industries, but they suffer from strength decrease and microstructural instability at elevated temperatures, rendering it difficult to achieve satisfactory high-temperature superelasticity. Here, a novel Ti20Hf15Zr15Cu25Ni25 high-entropy HTSMA exhibiting large superelasticity with a fully recoverable strain of 4.0% at temperatures up to 285°C is designed with the high-entropy alloy concept by employing the sluggish diffusion and severe lattice distortion effects to suppress thermal softening. This work illuminates the design of novel high-performance functional materials for high-temperature applications.

Ratoon rice (RR) has been regarded as a labor-saving and beneficial production system. Nitrogen (N) surplus and reactive N losses (Nr losses) are effective environmental indicators used to evaluate the performance of N management. Few studies have assessed N surplus and Nr losses for Chinese RR. In this study, Chinese RR planting areas were divided into South China (SC), the southern part of East China (SEC), Central China (CC), the northern part of East China (NEC), and Southwest China (SW). N surplus and Nr losses were also calculated based on 782 studies using a quadratic model under optimized N management for the highest yield (OPT-yield), the highest N-use efficiency (NUE) (OPT-NUE), and the highest grain N uptake (OPT-N uptake). The RR yields in the five regions ranged from 9.98 to 13.59 t ha−1. The high-yield record was observed in SEC, while the low-yield record was observed in NEC. The highest and the lowest Nr losses were found in NEC and SC, respectively. N surplus was reduced, while the yield was maintained in SEC, CC, NEC, and SW under OPT-yield and OPT-N uptake, and N surplus and Nr losses were reduced in the five regions when targeting the highest NUE. Farmers should be encouraged to plant RR in SEC and CC. RR was also a good choice when N management measures were conducted in three other regions. To achieve a win–win situation for both yield and the environment, OPT-yield could serve to improve the N management of current conventional practices.

Metamagnetic shape memory alloys exhibit a series of intriguing multifunctional properties and have great potential for applications in magnetic actuation, sensing and magnetic refrigeration. However, the poor mechanical properties of these alloys with hardly any tensile deformability seriously limit their practical application. In the present work, we developed a Ni-Fe-Mn-In microwire that exhibits both a giant, tensile superelasticity and a magnetic-field-induced first-order phase transformation. The recoverable strain of superelasticity is more than 20% in the temperature range of 233–283 K, which is the highest recoverable strain reported heretofore in Ni-Mn-based shape memory alloys (SMAs). Moreover, the present microwire exhibits a large shape memory effect with a recoverable strain of up to 13.9% under the constant tensile stress of 225 MPa. As a result of the magnetic-field-induced first-order phase transformation, a large reversible magnetocaloric effect with an isothermal entropy change ΔSm of 15.1 J kg−1 K−1 for a field change from 0.2 T to 5 T was achieved in this microwire. The realization of both magnetic-field and tensile-stress-induced transformations confers on this microwire great potential for application in miniature multi-functional devices and provides an opportunity for multi-functional property optimization under coupled multiple fields.