Geographical origin identification of winter jujube(Ziziphus jujuba Dongzao')by using multi-element fingerprinting with chemometrics

Winter jujube(Ziziphus jujuba'Dongzao')is greatly appreciated by consumers for its excellent quality,but brand infringement frequently occurs in the market.Here,we first determined a total of 38 elements in 167 winter jujube samples from the main winter jujube producing areas of China by inductively coupled plasma mass spectrometer(ICP-MS).As a result,16 elements(Mg,K,Mn,Cu,Zn,Mo,Ba,Be,As,Se,Cd,Sb,Ce,Er,Tl,and Pb)exhibited significant differences in samples from different producing areas.Supervised linear discriminant analysis(LDA)and orthogonal projection to latent structures discriminant analysis(OPLS-DA)showed better performance in identifying the origin of samples than unsupervised principal component analysis(PCA).LDA and OPLS-DA had a mean identification accuracy of 87.84 and 94.64%in the testing set,respectively.By using the multilayer perceptron(MLP)and C5.0,the prediction accuracy of the models could reach 96.36 and 91.06%,respectively.Based on the above four chemometric methods,Cd,Tl,Mo and Se were selected as the main variables and principal markers for the origin identification of winter jujube.Overall,this study demonstrates that it is practical and precise to identify the origin of winter jujube through multi-element fingerprint analysis with chemometrics,and may also provide reference for establishing the origin traceability system of other fruits.

Research Progress on Prevention and Treatment of Diabetes with Traditional Chinese Medicine Based on Intestinal Flora

In recent years,the World Health Organization has proposed the concept that only intes‐tinal health can lead to longevity.It can be seen that gut microbiota plays an important role in maintaining human health,and gut microbiota has become a hot topic in medical research.With the change of Chinese residents'lifestyle,the incidence rate of diabetes is increasing rapidly.Research shows that the incidence of diabetes is closely related to intestinal flora imbalance.Traditional Chinese medicine can reduce blood sugar and improve clinical symptoms by regulating intestinal flora.Based on the theory of tradi‐tional Chinese medicine,this paper discusses the etiology and pathogenesis of intestinal flora imbalance,and provides a theoretical basis for traditional Chinese medicine to regu‐late intestinal flora to prevent and treat diabetes.Intestinal flora is a complex ecosystem,which plays an important role in maintaining human health.The imbalance of intestinal flora may lead to the occurrence of diabetes.The dynamic balance of gut microbiota is closely related to the kidneys,spleen,liver,and lungs.Traditional Chinese medicine monomer and compound can prevent and cure diabetes by regulating intestinal flora.

Response of stomatal conductance of two tree species to vapor pressure deficit in three climate zones

Stomatal behavior is a central topic of plant ecophysiological research under global environmental change. However, the physiological mechanism controlling the response of stomata to vapor pressure deficit （VPD） or relative humidity （RH） has been inadequately understood till now. In this study, responses of stomatal conduc- tance （gs） to VPD in two species of trees （Fraxinus chinensis Roxb., Populus alba L. var. pyramidalis Bge.）in three different climate zones （Jinan with typical warm humid/semi-humid climate, Urumqi with temperate continental arid climate and Turpan with extreme arid desert climate） were measured. Levels of two phytohormones （abscisic acid, ABA; indole-3-acetic acid, IAA） in the leaves of the two tree species at these three sites were also measured by high performance liquid chromatography. The results showed that the responses of gs to an increasing VPD in these two tree species at the three sites had peak curves which could be fitted with a Log Normal Model （gs=a.exp（-O.5（In（DIc）lb）2）. The VPD/RH values corresponding to the maximum g, can be calculated using the fitting models for the two tree species in the three sites. We found that the calculated g, -VPD correlated nega- tively with relative air humidity in the three sites during the plant growth period （April to October 2010）, which showed the values of g,-max-VPD were related to the climate conditions. The prevailing empirical stomatal model （Leuning model） and optimal stomatal behavior model could not properly simulate our measured data. The water use efficiency in the two tree species did not show obvious differences under three very different climatic conditions, but the highest gs, photosynthetic and transpiration rates occurred in P. alba var. of Turpan. The sensitivity in re- sponse of g~ to VPD in leaves of the two trees showed positive correlations with the concentration of ABA, which implied that ABA level could be used as an indicator of the sensitivity of stomatal response to VPD. Our results confirmed that the prediction of the response of gs to VPD might be incomplete in the two current popular models. Therefore, an improved g, model which is able to integrate the results is needed. Also, the stomatal response mechanism of single peak curves of g~ to VPD should be considered.

2016 Chinese expert consensus and guidelines for the diagnosis and treatment of papillary thyroid microcarcinoma

The incidence of papillary thyroid carcinoma(PTC)has exponentially increased in recent years.Papillary thyroid microcarcinoma(PTMC)accounts for the majority of the reported cases of PTC.The debates and crucial issues in PTMC management have received researchers'attention.To further improve the clinical management of PTMC in China,

Development and validation of InDel markers for identification of QTL underlying flowering time in soybean

Soybean [Glycine max(L.) Merrill] is a major plant source of protein and oil. An accurate and well-saturated molecular linkage map is a prerequisite for forward genetic studies of gene function and for modern breeding for many useful agronomic traits. Next-generation sequence data available in public databases provides valuable information and offers new insights for rapid and efficient development of molecular markers. In this study, we attempted to show the feasibility and facility of using genomic resequencing data as raw material for identifying putative In Del markers. First, we identified 17,613 In Del sites among 56 soybean accessions and obtained 12,619 primer pairs. Second, we constructed a genetic map with a random subset of 2841 primer pairs and aligned 300 polymorphic markers with the 20 consensus linkage groups(LG). The total genetic distance was 2347.3 c M and the number of mapped markers per LG ranged from 10 to 23 with an average of 15 markers. The largest and smallest genetic distances between adjacent markers were 52.3 c M and 0.1 cM, respectively. Finally, we validated the genetic map constructed by newly developed In Del markers by QTL analysis of days to flowering(DTF) under different environments. One major QTL(qDTF4) and four minor QTL(qDTF20, qDTF13, qDTF12,and q DTF11) on 5 LGs were detected. These results demonstrate the utility of the In Del markers developed in this work for map-based cloning and molecular breeding in soybean.

Three-dimensional paper-like graphene framework with highly orientated laminar structure as binder-free supercapacitor electrode

A free-standing paper-like three-dimensional graphene framework（3DGF） with orientated laminar structure and interconnected macropores, was obtained by the hard template-directed ordered assembly. As the sacrificial templates, polystyrene（PS） latex spheres were assembled with graphene oxide（GO） to build up a sandwich type composite film, followed by heat removal of which with a simultaneous reduction of GO. The 3DGF exhibited high specific surface area of 402.5 m2/g, controllable pores and mechanical flexibility, which was employed as the binder-free supercapacitor electrode and shows high specific gravimetric capacitance of 95 F/g at 0.5 A/g, with enhanced rate capability in 3 electrode KOH system.

A dandelion-like carbon microsphere/MnO_2 nanosheets composite for supercapacitors

This article reported the electrochemical performance of a novel cabon microsphere/MnO2nanosheets(CMS/MnO2) composite prepared by a in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy(SEM) and transmission electron microscopy(TEM) revealed that MnO2nanosheets homogeneously grew onto the surface of CMS to form a loose-packed and dandelion-like core/shell microstructure. The unique microstructure plays a basic role in electrochemical accessibility of electrolyte to MnO2active material and a fast diffusion rate within the redox phase. The results of cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectrometry indicated that the prepared CMS/MnO2composite presented high capacitance of 181 F g-1and long cycle life of 61% capacity retention after 2000 charge/discharge cycles in 1 mol/L Na2SO4solution, which show strong promise for high-rate electrochemical capacitive energy storage applications.

Anti-Icing Method Based on Reducing Voltage of Transmission Lines

The icing of transmission lines threatens the security of power system. This paper proposes a novel anti-icing method based on reducing voltage of the transmission lines. The line voltage can be reduced by regulating the ratio of the transformers which install the both ends of the transmission lines. The line current can be increased and the power loss of the transmission lines can also be increased, which means the heat generated by power loss increases and the icing process of the transmission lines can be restrained. When the icing may occur in the atrocious weather, the anti-icing transformers installed the both ends of transmission line are put into operation. The ratios of transformers are regulated to the appropriate value. The current of transmission line can be increased to the value that is a little greater than the critical current, which can realize the purpose of anti-icing. At the same time, the conditions of normal running in the load side are kept invariably, which can ensure the security of power system. This method can be applicable to a wide range. It's an effective measure to prevent the icing of the transmission lines.

Software Defined Traffic Engineering for Improving Quality of Service

The Software Defined Networking(SDN) paradigm separates the control plane from the packet forwarding plane, and provides applications with a centralized view of the distributed network state. Thanks to the flexibility and efficiency of the traffic flow management, SDN based traffic engineering increases network utilization and improves Quality of Service(QoS). In this paper, an SDN based traffic scheduling algorithm called CATS is proposed to detect and control congestions in real time. In particular, a new concept of aggregated elephant flow is presented. And then a traffic scheduling optimization model is formulated with the goal of minimizing the variance of link utilization and improving QoS. We develop a chaos genetic algorithm to solve this NP-hard problem. At the end of this paper, we use Mininet, Floodlight and video traces to simulate the SDN enabled video networking. We simulate both the case of live video streaming in the wide area backbone network and the case of video file transferring among data centers. Simulation results show that the proposed algorithm CATS effectively eliminates network congestions in subsecond. In consequence, CATS improves the QoS with lower packet loss rate and balanced link utilization.

Prediction and observation of defect-induced room-temperature ferromagnetism in halide perovskites

The possibility to induce a macroscopic magnetic moment in lead halide perovskites(LHPs),combined with their excellent optoelectronic properties,is of fundamental interest and has promising spintronic applications.However,these possibilities remain an open question in both theory and experiment.Here,theoretical and experimental studies are performed to explore ferromagnetic states in LHPs originated from lattice defects.First-principle calculations reveal that shallow-level Br vacancies in defective CsPbBr3 can produce spin-splitting states and the coupling between them leads to a ferromagnetic ground state.Experimentally,ferromagnetism at 300 K is observed in room-temperature synthesized CsPbBr3 nanocrystals,but is not observed in hot-injection prepared CsPbBr3 quantum dots and in CsPbBr3 single crystals,highlighting the significance played by vacancy defects.Furthermore,the ferromagnetism in the CsPbBr3 nanocrystals can be enhanced fourfold with Ni2+ion dopants,due to enhancement of the exchange coupling between magnetic polarons.Room-temperature ferromagnetism is also observed in other LHPs,which suggests that vacancy-induced ferromagnetism may be a universal feature of solution-processed LHPs,which is useful for future spintronic devices.

Clean numerical simulation:a new strategy to obtain reliable solutions of chaotic dynamic systems

It is well-known that chaotic dynamic systems, e.g., three-body system and turbulent flow, have sensitive dependence on the initial conditions(SDIC). Unfortunately,numerical noises, i.e., truncation error and round-off error, always exist in practice. Thus,due to the SDIC, the long-term accurate prediction of chaotic dynamic systems is practically impossible. In this paper, a new strategy for chaotic dynamic systems, i.e., the clean numerical simulation(CNS), is briefly described, and applied to a few Hamiltonian chaotic systems. With negligible numerical noises, the CNS can provide convergent(reliable) chaotic trajectories in a long enough interval of time. This is very important for Hamiltonian systems, and thus should have many applications in various fields. It is found that the traditional numerical methods in double precision cannot give not only reliable trajectories but also reliable Fourier power spectra and autocorrelation functions(ACFs). In addition, even the statistic properties of chaotic systems cannot be correctly obtained by means of traditional numerical algorithms in double precision, as long as these statistics are time-dependent. The CNS results strongly suggest that one had better be very careful on the direct numerical simulation(DNS) results of statistically unsteady turbulent flows, although DNS results often agree well with experimental data when the turbulent flow is in a statistical stationary state.

Relative contributions of temperature and salinity to steric sea level over the South China Sea

The relative contributions of surface temperature and salinity to steric sea-level variations are investigated using satellite observations and reanalysis datasets.By defi ning a contribution factor,the relative roles of thermal and haline steric height variations are quantifi ed over the South China Sea(SCS).The thermosteric height dominates the steric sea level variation in the northern SCS deep basin,while the contribution of the halosteric height increases southward.Further investigation reveals that this transition is related to the meridional imbalance of surface heat flux and precipitation variations.The revealed steric constitution distribution is not confi ned to the surface but extends within the upper layer to approximately 50m depth,and then the thermosteric component dominates from the depth underneath.The results of this study clarify the steric sea level constitution over the SCS,benefit the understanding of sea-level variations at the regional scale,and may further facilitate multisensor remote sensing data mining studies.

Cold-Start Link Prediction via Weighted Symmetric Nonnegative Matrix Factorization with Graph Regularization

Link prediction has attracted wide attention among interdisciplinaryresearchers as an important issue in complex network. It aims to predict the missing links in current networks and new links that will appear in future networks.Despite the presence of missing links in the target network of link prediction studies, the network it processes remains macroscopically as a large connectedgraph. However, the complexity of the real world makes the complex networksabstracted from real systems often contain many isolated nodes. This phenomenon leads to existing link prediction methods not to efficiently implement the prediction of missing edges on isolated nodes. Therefore, the cold-start linkprediction is favored as one of the most valuable subproblems of traditional linkprediction. However, due to the loss of many links in the observation network, thetopological information available for completing the link prediction task is extremely scarce. This presents a severe challenge for the study of cold-start link prediction. Therefore, how to mine and fuse more available non-topologicalinformation from observed network becomes the key point to solve the problemof cold-start link prediction. In this paper, we propose a framework for solving thecold-start link prediction problem, a joint-weighted symmetric nonnegative matrixfactorization model fusing graph regularization information, based on low-rankapproximation algorithms in the field of machine learning. First, the nonlinear features in high-dimensional space of node attributes are captured by the designedgraph regularization term. Second, using a weighted matrix, we associate the attribute similarity and first order structure information of nodes and constrain eachother. Finally, a unified framework for implementing cold-start link prediction isconstructed by using a symmetric nonnegative matrix factorization model to integrate the multiple information extracted together. Extensive experimental validationon five real networks with attributes shows that the proposed model has very goodpredictive performance when predicting missing edges of isolated nodes.

Inhibitory effect of cyclosporin A on the immunological rejection of rats with cerebral hemorrhage following transplantation of nerve growth factors transfected glial cells

BACKGROUND： At present, it has been confirmed that immunological rejection exists in the cell transplantation in brain tissue, the effects of immunosuppressant on the immunological rejection and the survival of grafts in brain cell transplantation are worthy being investigated further. OBJECTIVE： To observe the immunological rejection after transgeneic cell transplantation in treating cerebra hemorrhage in rats, and investigate the interventional effect of cyclosprin. DESIGN ： A randomized controlled study SETTINGS： Second Affiliated Hospital of Xuzhou Medical College; First Affiliated Hospital of Nanjing Medica University. MATERIALS： Thirty-five healthy clean-degree SD rats of 6-8 weeks old were used, weighing 200-250 g, either male or female; The FACSort flow cytometer （American BD Company） and NYD-1000 image analytical system were used, The rat-anti-rat CD4 monoclonal antibody, rat-anti-rat CD8 monoclonal antibody, and rat-anti-rat MHC Ⅱ antigen monoclonal antibody were purchased from Santa Cruz Company; SP and DAB kits were purchased from Beijing Zhongshan Bio-engineering Company. XSP-8C2 light microscope was the product of Shanghai Zousun Optical Instrument, Co.,Ltd, and KYKY-3800B electron microscope was the product of China KYKY Technology Development Co.,Ltd. METHODS ： The experiments were carried out in the animal experimental center of Nanjing Medical University from April to July in 2003. ① Model establishment： The rats were anesthetized, and then the coordinates of left internal capsule were identified, and the needle was withdrawn after 120 μL blood was injected into the internal capsule. Adenoviruses were taken as the carriers, after the astrocytes were successfully transfected by nerve growth factor（NGF） gene, 0.2 mL cell suspension was injected into the sites of cerebral hemorrhage. Thirty successfully established rat models were randomly divided into cyclosporin A group （n=18） and control group, the rats were treated with intraperitoneal injection of cyclosporin A （10 mg/kg per day） intraperitoneal injection of saline of the same dosage from the 1^st day after transplantation, once a day for 7 days continuously.② CD4^＋ and CD4^＋ detection： The CD4^＋ and CD4^＋ T lymphocytes in caudal vein were counted with flow cytometer at 15 days after treatment. ③ Morphological observation in the transplanted sites： The rats were killed and then brain tissues were taken out, the transplanted sites and the structure of the normal brain tissue around the transplanted sites were observed with light and electron microscopes. ④Detections of the infiltration of T lymphocyte subsets and expression of major histocompatibility complex （MHC） Ⅱ antigen in the transplanted sites： The image analysis of immunohistochemical sections was performed with the image analytical system, and the integral optical density （IOD） was taken as the statistical value to observe the infiltration of T lymphocyte subsets and expression of MHC Ⅱ antigen in the transplanted sites, and the normal brain tissue around the transplanted sites were taken as controls. MATN OUTCOME MEASURES： ① Countings of CD4^＋ and CD4^＋ in peripheral blood; ②Results of the morphological observation in the transplanted sites; ③ Infiltration of T lymphocyte subsets and expression of MHC Ⅱ antigen in the transplanted sites RESULTS ： Totally 35 rats were used, and 30 were successfully made into models, 5 died during the treatment, the other 25 were involved in the analysis of results. ① Results of CD4^＋ and CD4^＋ T lymphocytes in pedpherel blood： The percentages of CD4^＋ and CD4^＋ T lymphocytes in the cyclosporin A group were （29.20±3.97）% and （20.65±2,02）%, respectively, which were obviously lower than those in the control group [（47,39±3,01）%, （28.30±2.36）%, t=-4.983, 4.012, P 〈 0.05], and the CDC/CD4^＋ ratio was obviously lower than that in the control group （1,41±0.86, 1,64^＋0.69, t=-3. 871, P〈 0.05）.② Morphological results in the transplanted sites： Under optical and electron microscopes, the survival region of the transplant was round, and it had an unobvious migration region with the normal brain tissues, the grafts had normal cellular form. Infiltrations of lymphocytes and monocytes were observed in both groups, and mainly located in the transplanted sites, and the expression of lymphocytes in the cyclosporin A group was markedly lower than that in the control group, and no above-mentioned changes were observed in the normal brain tissue around the transplanted sites. ③ Results of CD. and CD4^＋ T lymphocytes and expression of MHC Ⅱ antigen in the transplanted sites： The CD4^＋ and CD4^＋ T lymphocytes and expression of MHC Ⅱ antigen in the transplanted sites were observed in both groups. The IOD of CD4^＋ and CD4^＋ antigen positive cells in the cyclosporin A group were obviously lower than those in the control group （1.85±0.38, 1.44^＋0.33; 3.33±0.37, 2.648±0.56, /=-4.122, 4.434, P〈 0.05）, and the IOD of MHC Ⅱantigen positive cells was markedly lower than that in the control group （0.76±0.22, 0.94±0.24, t=3.885, P 〈 0.05）. CONCLUSION： There is immunological rejection in brain tissue after the transplantation of NSC transgeneic glial cells. ② The immunosuppressant of cyclosporin A can reduce the immunological rejection after the cell transplantation.

Transient Stability Analysis of Hu-Liao HVDC and AC Parallel Transmission System

In this paper, transient stability analysis was focused on Hu-Liao HVDC and AC parallel transmission system. The Hu-Liao HVDC project was introduced;Simulation method and mathematic models of AC and DC systems were stu-died as well as corresponding regulators and controllers. The dynamic performance and the interaction between AC and DC systems during serious disturbance were researched by detail time-domain simulation. Comparison was also made under different operation schemes. The research will bring important and significant reference for further operation and stability control of Hu-Liao HVDC and AC system.

Discovery of prenylated indole alkaloid and natural xanthone from cold-seep sediment derived fungus Talaromyces funiculosus SD-523

A new prenylated indole alkaloid 11,17-epi-mangrovamide A(1),a new natural occurring product,1,7-dihydroxy-6-methyl-8-hydroxymethyl-xanthone(2),two known alkaloids,mangrovamide A(3)and mangrovamide G(4),and four known polyketide derivatives(5–8)were isolated and identified from the cold-seep sediment derived fungal strain Talaromyces funiculosus SD-523.Their structures were elucidated by combination of nuclear magnetic resonance(NMR),high resolution electrospray ionization mass spectroscopy(HRESIMS),quantum chemical electronic circular dichroism(ECD),and DP4+probability analysis as well as by comparison of the data with literature reports.All isolated compounds were tested for antibacterial activities.

自我控制、同伴吸毒行为与态度与工读学校学生毒品使用行为的关系

本研究选择我国西南某工读学校的193名工读学生参加问卷调查,要求被试报告他们的毒品使用行为及其相关影响因素,以考察自我控制、同伴吸毒行为与态度和工读生毒品使用行为的关系。结果发现:(1)40.9%的工读学校学生曾使用过至少一种毒品。13%和39.4%的工读生报告曾使用过至少一种传统毒品或新型毒品。使用最多的毒品分别是K粉(38%)、冰毒(26%)和摇头丸(17%)。工读女生曾使用毒品的人数比例显著地高于男生(74%vs.35%)。使用毒品者普遍滥用2种以上的传统毒品和新型毒品;(2)工读生开始吸毒的年龄大约在12-14岁之间。38%的工读学生报告过去一年中,曾有人向他们提供或出售毒品。女生和曾使用毒品者较其他群体更容易接触到毒品;(3)Amos结果表明,同伴吸毒行为和态度可以直接地预测工读学生的毒品使用行为,同时,良好和不良的自我控制又通过同伴吸毒行为和态度间接地预测工读生的毒品使用行为。

父母和同伴因素对青少年饮酒行为的影响

环境是影响青少年饮酒行为的重要因素之一。本研究以南京市初一、初二、高一、高二共995个中学生为被试,考察父母和同伴因素对青少年饮酒行为的影响以及相对影响力。要求青少年自我报告他们自己、父母和同伴的饮酒行为和态度以及父母监控、父母教养方式情况。结果表明:(1)青少年的饮酒行为较为普遍,70%左右的青少年曾饮过啤酒或葡萄酒,25%左右的青少年曾饮过白酒。约10%的青少年经常饮啤酒和葡萄酒,2%的青少年经常饮白酒;(2)父/母饮酒行为和态度、父母监控、父母教养方式、同伴饮酒人数和态度与青少年的饮酒行为显著相关;(3)Amos结果表明,父母饮酒行为和态度对青少年饮酒行为有直接的预测作用,父母饮酒行为和态度还通过同伴饮酒人数和态度间接地预测青少年的饮酒行为。同时,父母饮酒行为和态度对青少年饮酒行为的影响力大于同伴饮酒行为和态度的影响力。

普通白光联合窄带成像放大内镜对早期胃癌浸润深度的诊断价值

目的:建立普通白光内镜(conventional white light endoscopy,C-WLE)联合窄带成像放大内镜(magnifying endoscopy with narrow-band imaging,ME-NBI)诊断早期胃癌(early gastric cancer,EGC)浸润深度的模型,提高EGC深度诊断的准确性。方法:回顾性分析2018年1月至2020年10月河北医科大学第四医院行黏膜下剥离术(endoscopic submucosal dissection,ESD)或手术治疗的241例EGC患者,用χ^(2)检验分析EGC黏膜下深层浸润的危险因素,应用Logistic回归模型分析EGC黏膜下深层浸润内镜下表现的独立危险因素,构建预测EGC浸润深度模型。结果:χ2检验结果表明黏膜皱襞变化、易出血、溃疡、边缘隆起、无血管区、扩张血管、微血管结构缺失、表面结构缺失是EGC黏膜下深层浸润的危险因素。Logistic多因素回归分析表明溃疡(OR=5.696,95%CI:1.656~19.590;P=0.006),边缘隆起(OR=5.363,95%CI:1.469~19.573;P=0.011),无血管区(OR=8.990,95%CI:2.522~32.042;P=0.001),扩张血管(OR=8.435,95%CI:3.323~21.408;P<0.001)为EGC黏膜下深层浸润的独立危险因素。将上述独立危险因素分别赋分为4分、4分、5分、5分,构建预测浸润深度的模型,AUC为0.802,最佳临界点为8分,诊断敏感度为71.4%,特异度为85.6%,准确率为82.5%。结论:依据C-WLE联合ME-NBI诊断EGC黏膜下深层浸润的独立危险因素构建的诊断模型有助于术前准确诊断EGC的浸润深度。

高结构稳定性、低泄漏率三维铜@石墨烯复合相变材料的制备

由于能源消费需求的持续增长和传统化学燃料的日益枯竭,对可再生能源的需求日益迫切。以地热能、太阳能为代表的可再生能源脱颖而出。然而,这些能源的应用易受到天气、季节、地点和时间的影响,具有不稳定性、随机性、波动性和间歇性。储能技术是解决上述问题的有效途径,它可以在需要的时候储存或释放能量。在各种储能技术可选材料中,相变材料(PCMs)是智能热能管理和便携式热能领域的有力候选者。大多数相变材料都存在导热系数低、环境污染、熔点泄漏等问题,因此有必要将相变材料封装到支撑骨架材料中。事实上,支撑材料在应用中仍面临着一些重大挑战。首先,骨架材料应能抵抗相变材料在相变过程中的体积变化,即具有良好的结构稳定性。其次,还应具有较高的导热系数和较低的泄漏率。石墨烯气凝胶(GA)已被证明是提高相变材料形状稳定性的有效支撑骨架,但相变引起的泄漏和网络结构的脆性是制约其应用的关键问题。在此,我们提出了一种双脉冲电镀的强化策略,用于制备铜@石墨烯气凝胶(Cu@GA)作为相变储能骨架材料。这一结构设计中,石墨烯气凝胶上的石墨烯片层上均匀地镀上了铜层,且不同片之间被铜镀层所连接。这种铜增强石墨烯气凝胶网络结构赋予复合材料良好的导热性和坚固的骨架稳定性,有利于增强相变换热和抑制相变过程中的泄漏。此外,通过真空浸渍法将十八胺(ODA)封装在Cu@GA骨架中,获得了结构稳定性高、泄漏率低的复合相变材料(Cu@GA/ODA),保证了ODA在Cu@GA骨架材料中的均匀分散和填充。通过比较复合相变材料的重量变化,研究了不同骨架对复合相变材料泄漏率的影响。优化后的复合相变材料(CPCM)Cu@GA/ODA经20次储热、放热循环后,泄漏率降低至19.82%(w,质量分数),而GA/ODA和GOA/ODA为骨架的复合相变材料的泄漏率分别为80.31%(w)和72.99%(w)。为了探讨这种影响的原因,用扫描电子显微镜(SEM)观察了循环后骨架的形貌。铜/石墨烯气凝胶(Cu@GA)骨架材料没有明显的收缩或坍塌,仍可以保持完整的三维网络结构,而氧化石墨烯气凝胶(GOA)和石墨烯气凝胶(GA)的骨架材料三维结构不复存在,且在氧化石墨烯/石墨烯片能够观察到明显的裂隙。铜涂层可以提高骨架的微观结构稳定性,有利于提高结构稳定性,降低复合材料的泄漏率。同时,该研究为构建理想的金属增强石墨烯气凝胶复合骨架材料铺平了新的道路,该复合材料具有优异的综合性能,可用于未来的相变储能、多孔微波吸收和储能应用。