Recent advances in graphene-based phase change composites for thermal energy storage and management

Energy storage and conservation are receiving increased attention due to rising global energy demands.Therefore,the development of energy storage materials is crucial.Thermal energy storage(TES)systems based on phase change materials(PCMs)have increased in prominence over the past two decades,not only because of their outstanding heat storage capacities but also their superior thermal energy regulation capability.However,issues such as leakage and low thermal conductivity limit their applicability in a variety of settings.Carbon-based materials such as graphene and its derivatives can be utilized to surmount these obstacles.This study examines the recent advancements in graphene-based phase change composites(PCCs),where graphene-based nanostructures such as graphene,graphene oxide(GO),functionalized graphene/GO,and graphene aerogel(GA)are incorporated into PCMs to substantially enhance their shape stability and thermal conductivity that could be translated to better storage capacity,durability,and temperature response,thus boosting their attractiveness for TES systems.In addition,the applications of these graphene-based PCCs in various TES disciplines,such as energy conservation in buildings,solar utilization,and battery thermal management,are discussed and summarized.

Recent progress on fabrication, spectroscopy properties, and device applications in Sn-doped CdS micro-nano structures

One-dimensional semiconductor materials possess excellent photoelectric properties and potential for the construction of integrated nanodevices. Among them, Sn-doped CdS has different micro-nano structures, including nanoribbons,nanowires, comb-like structures, and superlattices, with rich optical microcavity modes, excellent optical properties, and a wide range of application fields. This article reviews the research progress of various micrometer structures of Sn-doped CdS, systematically elaborates the effects of different growth conditions on the preparation of Sn-doped CdS micro-nano structures, as well as the spectral characteristics of these structures and their potential applications in certain fields. With the continuous progress of nanotechnology, it is expected that Sn-doped CdS micro-nano structures will achieve more breakthroughs in the field of optoelectronics and form cross-integration with other fields, jointly promoting scientific, technological, and social development.

Additive manufacturing of Ni-based superalloys: Residual stress, mechanisms of crack formation and strategies for crack inhibition

The additive manufacturing(AM)of Ni-based superalloys has attracted extensive interest from both academia and industry due to its unique capabilities to fabricate complex and high-performance components for use in high-end industrial systems.However,the intense temperature gradient induced by the rapid heating and cooling processes of AM can generate high levels of residual stress and metastable chemical and structural states,inevitably leading to severe metallurgical defects in Ni-based superalloys.Cracks are the greatest threat to these materials’integrity as they can rapidly propagate and thereby cause sudden and non-predictable failure.Consequently,there is a need for a deeper understanding of residual stress and cracking mechanisms in additively manufactured Ni-based superalloys and ways to potentially prevent cracking,as this knowledge will enable the wider application of these unique materials.To this end,this paper comprehensively reviews the residual stress and the various mechanisms of crack formation in Ni-based superalloys during AM.In addition,several common methods for inhibiting crack formation are presented to assist the research community to develop methods for the fabrication of crack-free additively manufactured components.

Wax from Pyrolysis of Waste Plastics as a Potential Source of Phase Change Material for Thermal Energy Storage

Over the past half-century, plastic consumption has grown rapidly due to its versatility, low cost, and unrivaled functional properties. Among the diff erent implemented strategies for recycling waste plastics, pyrolysis is deemed the most economical option. Currently, the wax obtained from the pyrolysis of waste plastics is mainly used as a feedstock to manufacture chemicals and fuels or added to asphalt for pavement construction, with no other applications of wax being reported. Herein, the thermal pyrolysis of three common waste polyolefin plastics: high-density polyethylene(HDPE), low-density polyethylene(LDPE), and polypropylene(PP), was conducted at 450 ℃. The waste plastics-derived waxes were characterized and studied for a potential new application: phase change materials(PCMs) for thermal energy storage(TES). Gas chromatography–mass spectrometry analysis showed that paraffin makes up most of the composition of HDPE and LDPE waxes, whereas PP wax contains a mixture of naphthene, isoparaffin, olefin, and paraffin. Diff erential scanning calorimetry(DSC) analysis indicated that HDPE and LDPE waxes have a peak melting temperature of 33.8 ℃ and 40.3 ℃, with a relatively high latent heat of 103.2 J/g and 88.3 J/g, respectively, whereas the PP wax was found to have almost negligible latent heat. Fourier transform infrared spectroscopy and DSC results revealed good chemical and thermal stability of HDPE and LDPE waxes after 100 cycles of thermal cycling. Performance evaluation of the waxes was also conducted using a thermal storage pad to understand their thermoregulation characteristics for TES applications.

Thermal and Electrical Properties of Liquid Metal Gallium During Phase Transition

Liquid metal gallium has been widely used in numerous fields, from nuclear engineering, catalysts, and energy storage to electronics owing to its remarkable thermal and electrical properties along with low viscosity and nontoxicity. Compared with high-temperature liquid metals, room-temperature liquid metals, such as gallium(Ga), are emerging as promising alternatives for fabricating advanced energy storage devices, such as phase change materials, by harvesting the advantageous properties of their liquid state maintained without external energy input. However, the thermal and electrical properties of liquid metals at the phase transition are rather poorly studied, limiting their practical applications. In this study, we reported on the physical properties of the solid–liquid phase transition of Ga using a custom-designed, solid–liquid electrical and thermal measurement system. We observed that the electrical conductivity of Ga progressively decreases with an increase in temperature. However, the Seebeck coefficient of Ga increases from 0.2 to 2.1 μV/K, and thermal conductivity from 7.6 to 33 W/(K·m). These electrical and thermal properties of Ga at solid–liquid phase transition would be useful for practical applications.

不同熔盐体系中Sb_(2)S_(3)一步电还原脱硫

对NaCl-KCl、NaCl-CaCl_(2)、NaCl-Na_(2)CO_(3)、NaCl-KCl-CaCl_(2)和NaCl-KCl-Na_(2)CO_(3)熔盐体系开展比较分析,研究不同熔盐体系的相图、热稳定性和硫化锑的溶解度。根据锑元素分布特征、电流效率、能耗及熔渣成分表征结果,优选出适合Sb_(2)S_(3)电解还原的熔盐体系。结果表明,所有熔盐体系均具有良好热稳定性,且可实现Sb_(2)S_(3)的电解还原。添加CaCl_(2)的体系不利于Sb_(2)S_(3)溶解,而添加Na_(2)CO_(3)的体系会与Sb_(2)S_(3)发生反应。此外,NaCl-KCl体系的电流效率最高(75.68%),且能耗最低(2.18 k W·h/kg)。

Precise measurement of 171Yb magnetic constants for 1S_(0)–3P_(0) clock transition

We present a precise measurement of171Yb magnetic constants for 1S_(0)-3P_(0) clock transition. The background magnetic field is firstly compensated to < 1 m Gs(1 Gs = 10^(-4)T) through measuring the splitting of two π transitins of171Yb clock transition at different compensation coils currents. Then, the splitting ratios of the π and σ components of171Yb clock transition at different bias magnetic fields are measured, and the first-order Zeeman coefficient is determined to beα = 199.49(5) Hz/Gs. The second-order Zeeman shifts at various bias magnetic fields are also measured through interleaved self-comparison in which the bias magnetic fields are modulated between high and low values. The second-order Zeeman coefficient is fitted to be β =-6.09(3) Hz/m T^(2), which is consistent with the result of NIST group.

Recoloring tomato fruit by CRISPR/Cas9-mediated multiplex gene editing

Fruit color is an important horticultural trait,which greatly affects consumer preferences.In tomato,fruit color is determined by the accumulation of different pigments,such as carotenoids in the pericarp and f lavonoids in the peel,along with the degradation of chlorophyll during fruit ripening.Since fruit color is a multigenic trait,it takes years to introgress all color-related genes in a single genetic background via traditional crossbreeding,and the avoidance of linkage drag during this process is difficult.Here,we proposed a rapid breeding strategy to generate tomato lines with different colored fruits from red-fruited materials by CRISPR/Cas9-mediated multiplex gene editing of three fruit color-related genes(PSY1,MYB12,and SGR1).Using this strategy,the red-fruited cultivar‘Ailsa Craig’has been engineered to a series of tomato genotypes with different fruit colors,including yellow,brown,pink,light-yellow,pink-brown,yellow-green,and light green.Compared with traditional crossbreeding,this strategy requires less time and can obtain transgene-free plants with different colored fruits in less than 1 year.Most importantly,it does not alter other important agronomic traits,like yield and fruit quality.Our strategy has great practical potential for tomato breeding and serves as a reference for improving multigene-controlled traits of horticultural crops.

Numerical Study on Mechanism of Blast-Induced Damage Considering Guiding Effect of Water Jet Slot

Damage is one of the most important characteristics of rock failure.Studying the damage mechanism of rock blasting under the guiding effect of the water jet slot and revealing the mechanism of controlled blasting with water jet assistance are crucial.In this study,a rock-like material was chosen as the research object for the calibration experiment of the numerical model.The numerical simulation models were then established by ANSYS/LS-DYNA,and the blastinduced damage mechanism under the guiding effect of the water jet slot was analyzed according to the blasting theory.The results indicated that explosive energy accumulates toward the direction of the slot as the guiding effect of the water jet slot,which allows the rock mass in the direction of the slot bear more damage.Meanwhile,the rock mass in the middle of the connection line between two blast-holes bears more damage under the combination of the effect of the explosion stress wave and guiding effect of water the jet slot on the detonation gas during double-slotted borehole blasting,which results in the formation of a gourd-shaped blast-induced damage area.In addition,the influence of the water jet slot on blast-induced damage varies depending on the blasting-process stage.

Uncovering the miRNA-mediated regulatory network involved in Ma bamboo(Dendrocalamus latiflorus)de novo shoot organogenesis

Bamboo is an important non-timber forest product and is well-known for its reluctance to regenerate.Recently we have established a de novo shoot organogenesis(DNSO)protocol in Ma bamboo(Dendrocalamus latiflorus)and revealed the transcriptomic dynamics during Ma bamboo regeneration,which suggested the potential roles of Ma bamboo microRNAs(DlamiRNAs)in this process.However,how DlamiRNAs regulate bamboo DNSO is poorly understood.Here we performed integrated analysis with sRNAome,degradome,and transcriptome sequencing by using samples covering the four stages of the bamboo DNSO process.A total of 727 DlamiRNAs showed differential expression during the bamboo DNSO process,and the core DlamiRNA-DlamRNA-mediated regulatory networks for bamboo DNSO were constructed.Based on the results,DlamiR156 was selected for further functional characterization of its potential roles in bamboo DNSO.Transgenic bamboos with increased DlamiR156 levels exhibited an enhancement in their regeneration efficiency.Conversely,when DlamiR156 levels were downregulated,the regeneration efficiencies of transgenic bamboos decreased.Our findings show that the DlamiRNA-mediated regulatory pathways are significant in the process of bamboo regeneration and will contribute to our understanding of the molecular mechanisms governing plant organogenesis in a more comprehensive manner.

Teaching Reform and Practice of Software Engineering Graduate Students by Implanting Scientific Research Literacy into Classroom Teaching Content

How to cultivate and improve graduate students’innovation and practical abilities in software engineering through the curriculum and teaching mode reform is an important issue.In this paper,a research literacy-driven teaching mode is proposed.It assists in the reform of the curriculum system.Then,a curriculum system construction framework is proposed,which involves the integration of research literacy into classroom teaching content.It assists in the cultivation of research abilities of graduate students in software engineering.The effectiveness of the curriculum reform is demonstrated through questionnaire surveys and research outcomes of the project team.The results show that the methods explored in this paper can serve as valuable references for future course design and teaching practice in computer-related courses for graduates.

鼠神经生长因子、亚低温联合甲强龙在急性脊髓损伤中的应用及对氧化应激水平的影响

目的探讨鼠神经生长因子、亚低温联合甲强龙治疗急性脊髓损伤的临床疗效及对氧化应激水平的影响。方法选取2016年5月—2018年6月延安大学附属医院收治的急性脊髓损伤患者132例作为研究对象。按随机数字表法分为对照组和观察组,每组66例。对照组静脉滴注甲强龙,初始剂量为30 mg/kg,随后以5.4 mg/(kg·h)的速度持续静脉滴注23 h,同时给予亚低温治疗,降温同时给予静脉滴注冬眠合剂维持24 h;观察组在对照组的基础上,肌内注射鼠神经生长因子30 g/d,持续给药2个月。观察两组患者脊髓功能恢复情况,包括:ADL、运动、触觉及针刺觉检查评分;观察血清GSH-Px和SOD的变化,追踪两组患者的并发症。结果两组患者治疗后ADL、运动、触觉及针刺觉检查评分较治疗前升高(P<0.05);观察组的评分高于对照组(P<0.05);两组患者治疗后血清GSH-Px和SOD水平较治疗前升高(P<0.05);观察组的氧化应激水平高于对照组(P<0.05);两组患者并发症发生率差异无统计学意义(P>0.05)。结论在甲强龙背景治疗下,鼠神经生长因子联合亚低温能促进急性脊髓损伤患者的神经功能恢复,提高患者的生活质量。

Analysis of the Short-Term Curative Effect of Roxadustat in Treating Renal Anemia in Patients with Peritoneal Dialysis

Objective:To analyze the short-term curative effect of roxadustat in the treatment of renal anemia in patients with peritoneal dialysis.Methods:70 patients with peritoneal dialysis renal anemia admitted to the dialysis department of our hospital from March 2021-March 2023 were selected as research objects,divided into a research group and a reference group according to random number drawing method,with each group consisting of 35 cases.The patients in the research group were treated with roxadustat,and those in the reference group were treated with recombinant human erythropoietin.The total efficacy,anemia index,iron metabolism index,and occurrence of adverse reactions were compared between the two groups.Results:The total efficacy of the treatment received in the research group was significantly higher than that in the reference group(P<0.05).In terms of anemia indicators,there was no statistically significant difference between the hemoglobin(Hb),the red blood cell(RBC),and the hematocrit(HCT)of both groups(P>0.05)before treatment.After treatment,the anemia indicators of the patients in the research group were significantly better than those in the reference group,(P<0.05).In terms of iron metabolism,before treatment,there was no significant difference between the total iron-binding capacity(TIBC),the transferrin(TRF),the ferritin(FER),and iron(Fe)of both groups(P>0.05).After treatment,the research group’s iron metabolism indicators were significantly better than those of the reference group(P<0.05).The incidence of adverse reactions in the research group was significantly lower than that in the reference group(P<0.05).Conclusion:The short-term curative effect of roxadustat in the treatment of peritoneal dialysis patients was demonstrated through this study,making it a viable treatment option.

微单倍型遗传标记的法医基因组学研究

微单倍型(microhaplotype,MH)是在一定DNA片段范围之内,由至少两个单核苷酸多态性位点组成的遗传标记。MH兼具无stutter伪峰、多态性丰富以及扩增子较小等特点,有望成为法医学上的一种新型遗传标记。为了从全基因组维度上分析MH的特征,进一步发掘其应用潜能,本研究基于千人基因组计划中105个中国南方汉族个体的全基因组测序数据,构建了迄今为止最全面的MH数据集。结果表明,人类基因组中350 bp范围之内的MH位点数量共计9,490,075个,且微单倍型分布密度对染色体变异水平具有提示作用。从多种碱基跨度范围对MH的多态性分析表明,其多态性潜能可达到或者超过常用短串联重复序列位点的水平。此外,本文归纳总结了MH组装灵活等特点,并提出了构建微单倍型数据库的方案。

基于全基因组数据的AI-SNPs筛选及大陆次级区域内群体遗传结构差异研究

在涉及多群体样本的医学研究中,群体遗传结构差异是不容忽视的影响因素之一。利用族源信息单核苷酸多态性遗传标记(ancestry-informative single nucleotide polymorphism,AI-SNP),通过分析群体遗传成分、推断个体遗传背景并对群体样本进行预筛选,可以有效降低群体遗传结构差异对医学研究影响。鉴于已发表的研究多为解析大陆间、大陆次级区域间的群体遗传结构差异,本研究拟基于千人基因组计划(GRCh37.p13)中东亚五群体:日本东京群体(Japanese in Tokyo,JPT)、北京汉族(Han Chinese in Beijing,CHB)、南方汉族(Southern Han Chinese,CHS)、西双版纳傣族(Chinese Dai in Xishuangbanna,CDX)、越南京族(Kinh in Ho Chi Minh City,KHV)的数据,以FST值为标准筛选AI-SNP并分析大陆次级区域内群体遗传结构差异。结果表明,研究涉及的东亚群体可分为三簇:JPT、CHB和CHS、CDX和KHV。利用AI-SNP可成功解析个体的遗传背景,而群体代表性遗传成分占比超过80%的个体具有良好的群体代表性。本研究表明,基于FST值筛选一组AI-SNP用于核验样本遗传背景、筛选群体代表性样本的方法在降低大陆次级区域内群体遗传结构差异对群体相关医学研究的影响中具有实际应用价值。

Sonographic evaluation of proximal gastric accommodation in patients with functional dyspepsia

AIM: To assess the value of ultrasonography (US) in evaluation of proximal gastric accommodation disorder in patients with functional dyspepsia (FD). METHODS: Between April 2011 and March 2012, 45 patients with FD and 27 healthy volunteers were enrolled in this study. Two-dimensional ultrasound (2DUS) and 3-dimensional ultrasound (3DUS) were performed sequentially to measure proximal gastric area (PGA), maximal proximal gastric diameter (MPGD), and proximal gastric volume (PGV). These values were measured separately in the two groups every other 5 min for a duration of 25 min after the beginning of ingestion of a test meal. Air pocket grading was done separately for images of 2DUS and blocks of 3DUS obtained at five scanning time points. RESULTS: Both PGA and PGV of patients were significantly smaller than healthy controls (P = 0.000 and 0.002, respectively). Comparing the two parameters between the groups at each time point, the differences were also statistically significant (P = 0.000-0.013), except at 10 min for the PGV (P = 0.077). However, no overall difference was found between the groups in the MPGD measurements (P = 0.114), though it was statistically significant at a 20-minute examination point (P = 0.026). A total of 360 sets or blocks of images were obtained for both 2DUS and 3DUS. For the images analyzed by 2DUS, none were excluded because of gastric gas, and 50 (13.9%) and 310 (86.1%) sets were determined as air pockets grades 1 and 2, respectively. For the images analyzed by 3DUS, 23 (6.4%) blocks were excluded from the measurement due to presence of a large fundus air pocket (grade 3); fifty (13.9%) and 287 (79.7%) blocks were also graded as 1 and 2, respectively. CONCLUSION: Measurement of both PGA and PGV by 2DUS and 3DUS could be useful for assessment of the proximal gastric accommodation.

Semi-solid processing of aluminum and magnesium alloys:Status,opportunity,and challenge in China

Owing to its low cost,short process and low energy consumption,semi-solid processing(SSP)of aluminum(Al)and magnesium(Mg)alloys has been considered as a competitive approach to fabricate complicated components with excellent performance.Over the past decade,significant progress has been achieved in deeply understanding the SSP process,the microstructure and performance of the fabricated components in China.This paper starts with a retrospective overview of some common slurry preparation methods,followed by presenting the performance and the underlying mechanisms of SSP fabricated alloys.Then,the mainstream opinions on the microstructure evolution and rheological flow behavior of semi-solid slurry are discussed.Subsequently,the general situation and some recent examples of industrial applications of SSP are presented.Finally,special attention is paid to the unresolved issues and the future directions in SSP of Al and Mg alloys in China.

Grain size based low cycle fatigue life prediction model for nickel-based superalloy

Nickel-based superalloys are easy to produce low cycle fatigue(LCF)damage when they are subjected to high temperature and mechanical stresses.Fatigue life prediction of nickel-based superalloys is of great importance for their reliable practical application.To investigate the effects of total strain and grain size on LCF behavior,the high temperature LCF tests were carried out for a nickel-based superalloy.The results show that the fatigue lives decreased with the increase of strain amplitude and grain size.A new LCF life prediction model was established considering the effect of grain size on fatigue life.Error analyses indicate that the prediction accuracy of the new LCF life model is higher than those of Manson-Coffin relationship and Ostergren energy method.

Numerical investigation on flow process of liquid metals in melt delivery nozzle during gas atomization process for fine metal powder production

Based on volume of fluid(VoF)interface capturing method and shear-stress transport(SST)k-ω turbulence model,numerical simulation was performed to reveal the flow mechanism of metal melts in melt delivery nozzle(MDN)during gas atomization(GA)process.The experimental validation indicated that the numerical models could give a reasonable prediction on the melt flow process in the MDN.With the decrease of the MDN inner-diameter,the melt flow resistance increased for both molten aluminum and iron,especially achieving an order of 10^(2) kPa in the case of the MDN inner-diameter≤1 mm.Based on the conventional GA process,the positive pressure was imposed on the viscous aluminum alloy melt to overcome its flow resistance in the MDN,thus producing powders under different MDN inner-diameters.When the MDN inner-diameter was reduced from 4 to 2 mm,the yield of fine powder(<150μm)soared from 54.7%to 94.2%.The surface quality of powders has also been improved when using a smaller inner-diameter MDN.

Antimicrobial effect of alexidine and chlorhexidine against Enterococcus faecalis infection

A previous study demonstrated that alexidine has greater affinity for the major virulence factors of bacteria than chlorhexidine.The aim of this study was to compare the antimicrobial activity of 1%alexidine with that of 2%chlorhexidine using Enterococcus faecalis-infected dentin blocks.Sixty bovine dentin blocks were prepared and randomly divided into six groups of 10 each.E.faecalis was inoculated on 60 dentin blocks using the Luppens apparatus for 24 h and then the dentin blocks were soaked in 2%chlorhexidine or 1%alexidine solutions for 5 and 10 min,respectively.Sterile saline was used as a control.The antimicrobial efficacy was assessed by counting the number of bacteria adhering to the dentin surface and observing the degradation of bacterial shape or membrane rupture under a scanning electron microscope.Significantly fewer bacteria were observed in the 2%chlorhexidine-or 1%alexidine-soaked groups than in the control group(P<0.05).However,there was no significant difference in the number of bacteria adhering to the dentinal surface between the two experimental groups or between the two soaking time groups(P>0.05).Ruptured or antiseptic-attached bacteria were more frequently observed in the 10-min-soaked chlorhexidine and alexidine groups than in the 5-min-soaked chlorhexidine and alexidine groups.In conclusion,10-min soaking with 1%alexidine or 2%chlorhexidine can be effective against E.faecalis infection.