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Phase change materials (PCMs) are functional energy-storage materials that achieve reversible heat storage and release through phase transition processes. They have extensive applications in the thermal management and solar energy industries. However, their low electrical and thermal conductivities and poor stability often fail to meet application requirements. In this study, we utilised an abundant biomass-derived carbon source, sweet potatoes, to prepare a three-dimensional network of carbon aerogels. By simply vacuum-impregnating polyethylene glycol (PEG), the PCM was embedded in the carbon aerogel. The obtained PEG/carbon aerogel composite material exhibited high enthalpy (158.1 J/g) and good thermal and shape stability. They also demonstrated efficient photothermal (88.47 %) and electrothermal conversion (94.02 %). This research has significant potential for applications in solar energy storage and utilisation, building energy storage, space–ground thermal energy storage, and electronic device thermal management. This study provides a novel approach for the preparation and photothermal applications of bio-based PCMs.

A green and economical methodology to fabricate carbon-based materials with suitable pore size distributions is needed to achieve rapid electrolyte diffusion and improve the performance of supercapacitors. Here, a method combining in situtemplates with self-activation and self-doping is proposed. By variation of the molar ratio of magnesium folate and potassium folate, the pore size distribution was effectively adjusted. The optimal carbon materials (Kx) have a high specific surface area (1021–1676 m2g–1) and hierarchical pore structure, which significantly promotes its excellent capacitive properties. Notably, K2 shows an excellent mass specific capacitance of 233 F g–1at 0.1 A g–1. It still retained 113 F g–1at 55 A g–1. The assembled symmetric supercapacitor exhibited an outstanding cyclic stability. It maintains 100% capacitance after 100 000 cycles at 10 A g–1. The symmetric supercapacitor demonstrated a maximum power density of 99.8 kW kg–1. This study focuses on the preparation of layered pore structures to provide insights into the sustainable design of carbon materials.

Normal ground reaction forces (NGRFs) are key biomechanical parameters that determine the speed, stability, technique, and injury probability of skiers. However, most NGRF measurement devices are unsuitable for skiing due to limitations such as inconvenient portability, susceptibility to damage, and interference with human movement. Recently, it has been suggested that estimating NGRFs from data measured by inertial measurement units (IMUs) is feasible. However, most studies have only estimated NGRFs for simple movements such as walking or running with low estimation accuracy, and there are few studies for skiing. In addition, this article requires a large number of IMUs and has not optimized the number and layout of IMUs. Based on these issues, this article develops a new gated recurrent unit (GRU)-convolutional neural network (CNN)-particle swarm optimization (PSO)- bootstrap aggregating (bagging)-network (GCPB-Net) that utilizes IMUs to estimate NGRFs in multiple skiing movements. To improve the accuracy of the estimation model, the PSO-based multimodel fusion method and bagging ensemble learning are applied. To avoid limiting skiers’ mobility and increasing sensor costs, a dynamic IMU location optimization method based on maximum relevance and minimum redundancy (Dynamic-MRMR) is presented. With this optimization method, the optimal numbers and locations of IMUs for NGRF estimation in different skiing movements are given. This study is the first time to use machine learning and IMU layout optimization methods to estimate NGRFs in skiing. Based on the ablation and comparison experimental results, the GCPB-Net outperforms the base learners and most existing models.

This study focuses on distributed event-triggered consensus control under the scenario where only inaccurate agent model information is available. By designing a novel triggering error, a distributed dynamic event-triggered consensus (DETC) protocol is proposed for multiagent systems (MASs) with general linear dynamics over digraphs, without accurate a priori information of agent models. To improve the efficiency of the dynamic triggering law, a mixed triggering threshold is designed with a resilient function integrated to further enlarge interevent intervals. Within the proposed DETC protocol, the computational cost is significantly reduced especially for MASs with nonsparse and high-dimensional agent system matrices. In addition, for each individual agent, the states of neighboring agents used for triggering detections or controller updates are required in an on-demand (instead of continuous) way, which preserves communication resources and facilitates practical implementation. The feasibility of the designed DETC protocol is corroborated by rigorous theoretical analysis on consensus convergence and Zeno behavior exclusion. Finally, simulations are shown to demonstrate the effectiveness of the studied theory.

A novel process for manufacturing fiber-reinforced silica sol shells for investment casting is proposed. The influence of different fiber lengths and additions on the bending strength of the shell is investigated. Specifically, sisal fibers were suspended in a self-made fiber placement device under the influence of air fluidization and adhered to the surface of the backup slurry of shell. Both silica sol-immersed and untreated sisal fibers were employed as reinforcing agents for the investment shell. The results illustrate that fibers could be evenly placed on the surface of the shell with slurry by means of the air fluidization spread, thereby improving the strength of the fiber-reinforced shell. When the fiber length remained constant, the shell strength exhibited an initial increase followed by a decrease with an increase in fiber addition. At a fiber addition of 1.0%, the green strength of the shell reinforced with both treated and untreated fibers of length 4 mm reached its maximum values, which were 3.35 MPa and 3.14 MPa, respectively. When the fiber addition was 0.25%, the fired strength of the shell reinforced with the aforementioned two types of fibers reached their respective maximum values of 6.12 MPa and 5.86 MPa.

The development of sustainable composites necessitates biobased epoxy resins that are highly recyclable and degradable; however, the integration of mechanical, reprocessing, and rapid degradation properties into a single epoxy resin remains a significant challenge. The present study proposes a straightforward approach to overcoming the problem by combining two labile covalent bonds into an epoxy resin. The combination of acetal and disulfide bonds demonstrates a synergistic effect on the degradation performance of epoxy resin, leading to an ultrafast degradation of the epoxy polymer. The carbon fiber-reinforced composite with the epoxy resin matrix shows a tensile strength exceeding 630 MPa, but the epoxy resin degrades completely within just 8 min, while the recovered carbon fibers display nondestructive characteristics similar to those of the original material. Moreover, the epoxy resin that we designed shows good self-healing and reprocessing ability. Scratches on the resin surface can be completely self-healed by heating, while the powdered resin can be reshaped under a hot press. These findings offer a new approach to the preparation of sustainable composites, highlighting the significant importance of the development of thermosetting polymers.

The capture of carbon dioxide (CO2) from fuel gases is a significant method to solve the global warming problem. Metal–organic frameworks (MOFs) are considered to be promising porous materials and have shown great potential for CO2adsorption and separation applications. However, the adsorption and diffusion mechanisms of CO2in functionalized MOFs from the perspective of binding energies are still not clear. Actually, the adsorption and diffusion mechanisms can be revealed more intuitively by the binding energies of CO2with the functionalized MOFs. In this work, a combination of molecular dynamics simulation and density functional theory calculation was performed to study CO2adsorption and diffusion mechanisms in five different functionalized isoreticular MOFs (IRMOF-1 through -5), considering the influence of functionalized linkers on the adsorption capacity of functionalized MOFs. The results show that the CO2uptake is determined by two elements: the binding energy and porosity of MOFs. The porosity of the MOFs plays a dominant role in IRMOF-5, resulting in the lowest level of CO2uptake. The potential of mean force (PMF) of CO2is strongest at the CO2/functionalized MOFs interface, which is consistent with the maximum CO2density distribution at the interface. IRMOF-3 with the functionalized linker −NH2shows the highest CO2uptake due to the higher porosity and binding energy. Although IRMOF-5 with the functionalized linker −OC5H11exhibits the lowest diffusivity of CO2and the highest binding energy, it shows the lowest CO2uptake. Accordingly, among the five simulated functionalized MOFs, IRMOF-3 is an excellent CO2adsorbent and IRMOF-5 can be used to separate CO2from other gases, which will be helpful for the designing of CO2capture devices. This work will contribute to the design and screening of materials for CO2adsorption and separation in practical applications.

Graphical Abstract:

Recently, significant progress has been made in the preparation and properties of fiber-reinforced shells for investment casting; however, the research on the enhancement mechanism of fiber is inadequate. Herein, the composite shell is prepared using the airflow placement fiber process, and the conventional method, preimmersion silica sol and preimmersion slurry methods are adopted to obtain different interfaces between the matrix and fibers. Combined with the directional tensile test and fracture morphology of the shell observed via scanning electron microscope and stereomicroscope, the fiber-reinforced mechanism of the shell is analyzed in detail. It is found that the shell with polypropylene fibers is strengthened by the fiber pull-out, debonding, debonding-deformation and bridging-deformation, even with the different interface bonding between the matrix and fibers. However, the main failure modes of fibers are different under different interface conditions. The fibers in the preimmersion slurry shell mainly fail in the form of debonding-deformation and bridging-deformation, which makes the green strength of composite shells increase significantly.

The high-fidelity finite element model (HFFEM) and Monte Carlo (MC) simulation of the blisk involve large number of calculations, which leads to low computational efficiency. In this case, an improved quasi-static mode compensation method (IQSMCM) and quadratic function-extremum response surface method (QF-ERSM) are proposed to investigate the probability distribution of mistuned blisk based on its vibration characteristics. The number of nodes and elements of IQSMCM relative to HFFEM are, respectively, reduced by 79.66 and 80.03%. Thus, the degrees of freedoms (DOFs) of IQSMCM are obviously reduced compared with that of HFFEM, and its computational efficiency is obviously increased. The maximum displacement shape (MDS) is investigated via IQSMCM. The computational efficiency is enhanced in the condition of ensuring the computational accuracy. Based on the investigation of maximum mode shape, the probability analysis is performed via QF-ERSM. The computational accuracy of QF-ERSM is improved by 93.80% compared with that of MC. Furthermore, the computational efficiency of QF-ERSM is higher 57.06% than that of QF-RSM. The sample history, extremum response surface function, sample history and distribution histogram of MDS are obtained via QF-ERSM, which provides an important guidance for the reliability research of the mistuned blisk. This research can be applied not only to aeroengine’s blisk but also to other large and complex mechanical structures in practical engineering.

Cesium tungsten bronze (CsxWO3)-doped PEG/sweet potato form-stable composites are fabricated through a facile two-step method of lyophilization and vacuum impregnation. Abundant starch microsphere enhances the PEG loading capacity above 72 % and also supplies capillary force as well as hydrogen bonding to improve the form-stability of the composites. Here, the latent heat, relative crystallinity (Xc), and light-thermal conversion efficiency of the system with 0.99 wt% CsxWO3reach to 137.7 J/g, 97.7 %, and 83.5 %, respectively. The light-thermal conversion efficiency increases from 64.3 % to 91.1 % with 2.00 wt% CsxWO3. Besides, the composites exhibit improved thermal stability and excellent thermal reliability. The prepared bio-based composites with low-cost have broad application prospects in the field of energy storage.

A microfluidic control technique was employed in the supplying of a hardener of acetic acid as a replacement for high volatility ammonium chloride solution to cure sodium silicate shells for investment casting. The mechanical and technological properties of the shell were investigated. The structure of gel film in shell was characterized through Fourier-transform infrared spectroscopy, thermal gravimetric analysis coupled with differential scanning calorimetry, and scanning electron microscopy. The results showed that the green and fired strength of the shell cured via droplet-based microfluidics of acetic acid solution with a concentration of 6.0 wt% reached a peak value of 30.04 and 8.13 MPa, increased by 152.6 and 19.2%, respectively, compared with the conventional immersion or dipping method. This extremely dramatic improvement in performance derived from a precise and controllable curing reaction through the unique microfluidic-based manipulation. A large number of micro-reactors was successfully constructed on the surfaces of coatings through controlling hardener supply in the micro-droplet so that an asynchronous curing reaction in multiple micro-zones of coating was achieved and the gel film was endowed with an excellent shrinkage cracking resistance. This unique characteristic of the controllable reaction greatly reduced shrinkage cracking and structural damage closely related to shrinking during initial curing. Therefore, the intrinsic bonding potential of the gel film was fully developed so that the strength of the shell was significantly improved.

Sodium silicate shell for investment casting is widely used in parts production. However, the key problems with this technique are that the shell has a low green strength, fired strength, and high residual strength in the shell; as well as environmental pollution resulting from toxic gas containing ammonia from the evaporation of ammonia liquor used as a hardener during the hardening process. The former is related to uncontrollable hardening reaction process, while the latter is related to hardener characteristics. In this work, the microfluidic technique was employed to precisely control of the hardening reaction of the shells, and aluminum potassium sulfate solution served as replacement for ammonia liquor. The green, fired, and residual strength of the shell specimens and their high-temperature self-load deformation were investigated. It is found that the hardening reaction can be effectively controlled, and the hardening characteristics of the shells were obviously improved. The bending strength of the shells increases initially and then decreases at the time of micro-droplet spreading. The specimens hardened for 8 min by micro-droplet method reached the highest green strength level of 37.48 MPa, a fired strength of 10.07 MPa, and a lowest high-temperature self-load deformation value of 0.18%, about 150%, 65% higher, and 53% lower than by the current immersion method, respectively. Moreover, the fracture surfaces of the specimens were observed using scanning electron microscopy (SEM). The results reveal that the number of cracks in the sodium silicate gel film in the shell decreased significantly. The cracking tendency caused by shrinkage stress during hardening was reduced. This is due to the accurate reactant flow control provided a large number of microreactors for sodium silicate hardening. The hardener micro-droplets with an excellent monodispersity dispersed in a small volume on the surface of a continuous phase of water glass film, the volume shrinkage caused by micro-hardening can easily be compensated by the continuous phase of the liquid sodium silicate in the adjacent region and the cracking stress is partially or completely relaxed. The shrinkage trend in the process of dehydration polymerization of sodium silicate decreased and the bending strength of shell specimen improved. Microfluidic technique provides a powerful means for accurate delivery of reactant and control of gel structure during shell hardening.

The large solid waste discharge of investment casting shells is closely related to its unstable performance of shells and uncontrolled curing reaction. The unique advantage of microfluidic technology is that it can effectively control the chemical reaction process. In the present work, an environmentally friendly citric acid widely used in food as hardening agent was employed to cure a sodium silicate shells. Droplets of citric acid solution with a concentration of 1.5 × 10−3mol/L were generated by microfluidic technology and spread on the surfaces of shell specimens driven by air flow to induce the shell hardening. The green-, fired-, residual-strength, high temperature self-weight deformation, and gas to permeability of the shell were investigated. The results showed that the peak strength reached 30.38 MPa for green shell and 10.61MPa for the fired shell, about 26.4% and 17.4% higher than the immersion method, respectively. The fracture morphology of the shell observed by SEM (Scanning Electron Microscopy) confirmed that the more uniform, and far less cracks and micropores formed on the sodium silicate film of shells hardened by microfluidic droplets than the dipping method. The analysis of FTIR (Fourier Transform Infrared Spectroscopy) reveals that the final products of sodium silicate gel cured by microfluidic droplets achieved a high degree of polymerization and generated a relatively dense Si–O–Si cellular structure. The phase composition and thermal stability of the shell were analyzed by XRD (X-ray Diffraction) and TG-DSC (Thermogravimetric Differential Scanning Calorimetry). The results demonstrate that the improvement in hardening performance of shells is due to reaction microfluidic technology that can precisely control the volume and rate of hardening agent droplets, which can improve the repeatability and stability of the reaction in a short time, as well as reduce the damage of the gel film during the hardening process, and improve the quality of the gel film. The resulting shell can achieve higher strength and stability.

The linear extended state observers (LESOs) have been widely employed in the saliency-based sensorless control of interior permanent magnet synchronous motor (IPMSM) drives for position and speed tracking. The performances of the LESO are mainly determined by its bandwidth. This paper focuses on the bandwidth determination of the third-order (3rd)-LESOs used in saliency-based sensorless control. A generic method for determining the bandwidth of the 3rd-LESO is proposed by means of the open-loop transfer function, by which both the position and speed tracking performances can be further revealed. The desired bandwidth can be roughly achieved by adjusting the natural frequency and subsequently precisely tuned via two damping factors for the specific application of sensorless control. Subsequently, general guidelines of the bandwidth determination are proposed and summarized. Moreover, an intuitive and improved fourth-order (4th)-LESO, which is extended from the conventional 3rd-LESO, is proposed and comprehensively analyzed for its application in the sensorless control. Compared with the conventional 3rd-LESO, the proposed 4th-LESO exhibits improved capability of the high frequency noise rejection and thus it is a promising candidate for the saliency-based sensorless control. Finally, all the theoretical analyses are verified experimentally on a 1-kW IPMSM drive.

The high-strength and thin-walled shells are extremely beneficial for not only rapid solidification of metal castings but also excellent for shell removal, its low residual strength and low solid waste discharge. In this work, short carbon fibers as reinforcement were induced into the shells. The strength of specimens and their fracture behavior at ambient temperature or high temperature in loading were investigated using scanning electron microscopy (SEM) and thermogravimetric-differential scanning calorimetry technique (TG-DSC). The results show that the bending strength of the shell progressively rises initially and then decreases rapidly with increasing content of fiber with a constant length. In particular, the shell reinforced with 0.42 wt% carbon fibers of length of 2.0 mm reaches a peak of green strength of 4.68 MPa and a peak of hot strength 16.06 MPa, respectively, approximately 89.47 and 61.20% higher than that of the unreinforced. Moreover, the peak of the fired strength of shell specimens containing 0.51 wt% fibers of length of 3.0 mm reaches 7.48 MPa, increasing by 61.20% in comparison with the unreinforced. However, the high-temperature self-weight deformation of the shell does not reveal positive correlation or monotonically increasing with the amount of fiber. Furthermore, the results revealed that the fracture types and failure patterns of fibers in shells were mostly related to fiber-fracture, pull-out and/or debonding during loading. These research results are beneficial to further improve this technology and promote the practical application to greatly reduce the generation and discharge of waste shells in the production of investment castings in the future.

In this article, an integrated coreless axial-flux permanent-magnet synchronous machine (AFPMSM) system is integrated with winding and drive/control circuits on a same printed circuit board (PCB) stator. The losses and thermal problems of winding and drive/control circuits are very important for the safe operation of the integrated PCB coreless AFPMSM system. First, the losses of each part of the integrated AFPMSM system are analyzed, including stator and rotor losses, drive controller losses and mechanical losses. Then, the thermal simulation model is established to evaluate the thermal characteristics. Furtherly, the losses and thermal performances are improved by redesigning the permanent-magnet pole-arc coefficient, the shape of winding and the circuit arrangement. Finally, two integrated PCB coreless AFPMSM system prototypes before and after improvement are manufactured and tested to validate the analysis results.

Belt and Road Initiative (BRI) aspects, i.e. open trade (OT), foreign direct investment (FDI), capital formation, and information and communication technology (ICT) exports, are fundamental for any nation’s sustainable Economic Development (ED). The paper seeks to examine the effect of those aspects on the ED of Saudi Arabia and other Middle East nations which participate in BRI. The study uses the yearly cross-sectional time-series data from 2013 to 2022. The dual-stage Generalized Method of Moments (GMM) is employed in the sample because the sum of parameters is smaller than the sum of moment clauses. The findings reveal that capital formation and FDI significantly and positively affect the ED, while OT and ICT exports negatively and insignificantly affect it. The general findings show that China’s external FDI has increased the ED in Saudi Arabia and other Middle East nations whereas OT shows an insignificance as the majority of emerging nations should capitalize industrial development and hearten export expansion. This study is an initial effort to examine the relationships among BRI aspects and sustainable ED in Middle East Nations using the GMM method.

The brief is concerned with the fast output consensus tracking problem of heterogeneous multi-agent systems (MASs) under the digraph with a directed spanning tree. A novel fixed-time control protocol is proposed within the hierarchical framework, which not only endows a feature of faster convergency but also offers a more flexible estimation on the settling time comparing with asymptotic and finite-time protocols. Within the developed protocol, the challenge and complexity caused by heterogeneities of agents’ dynamics and generalities of communication topologies can be fairly handled by recasting the fixed-time output consensus tracking problem into the problems of cooperative fixed-time estimation and local fixed-time tracking, separately. In upper layer, an elaborate potential function is designed to construct the fixed-time dynamic cooperative compensator to realize fast estimation of leader’s states. In lower layer, based on the implicit Lyapunov function approach, a local fixed-time tracking controller is designed for each agent to track the compensator’s states. Based on the incorporation of above two layers, each agent can track leader’s output within a fixed time.

With the development of wearable electronics, inorganic flexible thin films (f-TFs) with high thermoelectric performance have attracted increasing research interest. To further enhance the thermoelectric performance of p-type inorganic Sb2Te3-based f-TFs, we employed direct current treatment to tune the crystallinity by rationally tuning the direct current treatment time. Correspondingly, a high electrical conductivity of >845 S cm–1and a moderate Seebeck coefficient of >110 μV K–1within the entire measurement temperature range have been simultaneously achieved. Consequently, a high power factor of 12.84 μW cm–1K–2at 423 K has been realized in the as-prepared p-type Sb2Te3f-TF treated by a direct current of 5 A for 4 min. A flexible thermoelectric device has been further assembled to demonstrate the power-generating capacity. This study indicates that the direct current treatment is an effective method to improve the thermoelectric performance of Sb2Te3f-TFs.

Uniform poly-α-methylstyrene (PAMS) hollow core microcapsules (HCMs) are widely used as templates to fabricate glow discharge polymer (GDP) fuel capsules, which are fundamental devices for inertial confinement fusion (ICF) engineering. The sphericity and surface finish uniformity of PAMS HCMs are critical for achieving high-quality GDP fuel capsules. In this work, millimeter-scale PAMS HCMs were fabricated by a microencapsulation technique. The sphericity and surface finish uniformity were concurrently improved using di-t-butyl peroxide (DTBP). The mechanisms of these effects were also experimentally and theoretically investigated. The results show that DTBP distributes at the O-W2 interface of W1/O/W2 compound droplets, which resists the diffusion of molecules through the O-W2 interface bidirectionally. The resisted diffusion of H2O molecules into the O phase eliminates PAMS HCM surface defects. Additionally, the resistance of fluorobenzene (FB) molecules from diffusing from the O phase into the W2 phase can effectively extend the solidification of W1/O/W2 compound droplets and thus improve the spherical uniformity of the HCMs. Using these improved PAMS HCMs, GDP fuel capsules meeting the stringent requirements for ICF engineering are prepared, and the quality of which is beyond the National Ignition Facility standard.

Alcoholic liver injury (ALI) is the leading cause of serious liver disease, whereas current treatments are mostly supportive and unable to metabolize alcohol directly. Here we report a metabolic reprogramming strategy for targeted alcohol detoxification and ALI management based on a confined cascade nanoreactor. The nanoreactor (named AA@mMOF) is designed by assembling natural enzymes of alcohol oxidase (AOx) and aldehyde dehydrogenase (ALDH) in the cavity of a mesoporous metal organic framework (mMOF) nanozyme with intrinsic catalase (CAT)-like activity. By conducting confined AOx/CAT/ALDH cascade reactions, AA@mMOF enables self-accelerated alcohol degradation (>0.5 mg·mL–1·h–1) with negligible aldehyde diffusion and accumulation, reprogramming alcohol metabolism and allowing high-efficiency detoxification. Administered to high-dose alcohol-intoxicated mice, AA@mMOF shows surprising liver targeting and accumulation performance and dramatically reduces blood alcohol concentration and rapidly reverses unconsciousness and acute liver injury to afford targeted alcoholism treatment. Moreover, AA@mMOF dramatically alleviates fat accumulation and oxidative stress in the liver of chronic alcoholism mice to block and reverse the progression of ALI. By conducting confined AOx/CAT/ALDH cascade reactions for high-efficiency alcohol metabolism reprogramming, AA@mMOF nanoreactor offers a powerful modality for targeted alcohol detoxification and ALI management. The proposed confined cascade metabolic reprogramming strategy provides a paradigm shift for the treatment of metabolic diseases.

Styrene has been widely used as a reactive diluent for a variety of commercial unsaturated polyester resins (UPRs), but suffered from high volatility. In this work, we developed a bio‐based reactive diluent, 4‐vinylguaiacol glycidyl ether (DE4VG), via an epoxidation of 4‐vinylguaiacol (4VG). Excellent miscibility and high reactivity of DE4VG were demonstrated by a series of copolymerization tests with an unsaturated polyester prepolymer (named PMSD) synthesized from maleic anhydride, 1,3‐dihydroxypropane and succinic acid. While, significant advantages in terms of viscosity and volatility were confirmed. Additionally, DE4VG provides both vinyl and epoxide groups and the epoxide groups were cured using 4,4‐diamino diphenylmethane (DDM) to participate the network formation of the cured PMSD/DE4VG/TBPB/DDM resin, resulting in high glass transition temperature (Tg, 195°C), residual carbon (45.5%), tensile strength (41.75 MPa), and the elongation at break (4.5%), which were all significantly surpassed the cured PMSD/St/TBPB, PMSD/St/TBPB/DDM, PMSD/DE4VG/TBPB resin. This work provided a successful demonstration to replace styrene with a bio‐based reactive diluent in UPR preparation, not only overcame the high volatility of styrene, but also enhanced material performances of the cured resin.

The outbreak of COVID-19 provided a warning sign for society worldwide: that is, we urgently need to explore effective strategies for combating unpredictable viral pandemics. Protective textiles such as surgery masks have played an important role in the mitigation of the COVID-19 pandemic, while revealing serious challenges in terms of supply, cross-infection risk, and environmental pollution. In this context, textiles with an antivirus functionality have attracted increasing attention, and many innovative proposals with exciting commercial possibilities have been reported over the past three years. In this review, we illustrate the progress of textile filtration for pandemics and summarize the recent development of antiviral textiles for personal protective purposes by cataloging them into three classes: metal-based, carbon-based, and polymer-based materials. We focused on the preparation routes of emerging antiviral textiles, providing a forward-looking perspective on their opportunities and challenges, to evaluate their efficacy, scale up their manufacturing processes, and expand their high-volume applications. Based on this review, we conclude that ideal antiviral textiles are characterized by a high filtration efficiency, reliable antiviral effect, long storage life, and recyclability. The expected manufacturing processes should be economically feasible, scalable, and quickly responsive.

Following muscle injury, fibro‐adipogenic progenitors (FAPs) are rapidly activated and undergo apoptosis at the resolution stage, which is required for proper muscle regeneration. When excessive FAPs remain, it contributes to fibrotic and fatty infiltration, impairing muscle recovery. Mechanisms controlling FAP apoptosis remain poorly defined. We hypothesized that AMP‐activated protein kinase (AMPK) in FAPs mediates their apoptosis during the muscle regeneration. To test, AMPKα1fl/flPDGFRαCremice were used to knock out AMPKα1 in FAPs. Following AMPKα1 knockout, the mice were injected with phosphate‐buffered saline or glycerol to induce muscle injury. Tibialis anterior muscle and FAPs were collected at 3, 7 and 14 days post‐injury (dpi) for further analysis. We found that AMPKα1 deletion in FAPs enhanced p65 translocation to the nuclei by 110% (n= 3; P< 0.01). AMPKα1 knockout group had a higher gene expression of MMP‐9 (matrix metalloproteinase‐9) by 470% (n= 3; P< 0.05) and protein level by 39% (n= 3; P< 0.05). Loss of AMPKα1 up‐regulated the active TGF‐β1 (transforming growth factor‐β1) levels by 21% (n= 3; P< 0.05). TGF‐β promoted apoptotic resistance, because AMPKα1‐deficient group had 36% lower cleaved Caspase 3 (cCAS3) content (n= 3; P< 0.05). Fibrotic differentiation of FAPs was promoted, with increased collagen protein level by 54% (n= 3; P< 0.05). Moreover, obesity decreased phosphorylation of AMPK by 54% (n= 3; P< 0.05), which decreased cCAS3 in FAPs by 44% (n= 3; P< 0.05) and elevated collagen accumulation (52%; n= 3; P< 0.05) during muscle regeneration. These data suggest that AMPK is a key mediator of FAPs apoptosis, and its inhibition due to obesity results in fibrosis of regenerated muscle.

Polybenzoxazines have a variety of advantages over most polymers, but the brittle feature limits the range of their applications. The most effective way for benzoxazine toughing is to copolymerize them with a well‐designed benzoxazine monomer able to contribute self‐plasticizing action. Here, a new bio‐based benzoxazine was synthesized from diphenolic acid (DPA), the sustainable candidate of bisphenol A. By introducing three aliphatic chains into DPA, the special benzoxazine able to provide remarkable toughness effect is obtained. For the synthesis, DPA is amidated using lauryl amine to diphenolic lauramide (DLA) first, then convert to a benzoxazine (DLA‐la) by Mannich‐like reaction with lauryl amine and paraformaldehyde. A commercial benzoxazine, bis(4‐(2H‐benzo[e][1,3]oxazin‐3(4H)‐yl)phenyl)methane (PH‐ddm), is employed as the toughing object to test the possibility of using DLA‐la would offer a significant toughing effect. Experimental results show that DLA‐la/PH‐ddm blending would result in a perfect resin without phase separation, which exhibits an improved elongation at break higher by 70.5% than the bulk PH‐ddm resin, while keeps tensile strength at 44.69 MPa. As the proposed toughing principle could be applied to a variety of commercially available benzoxazines, this research broadly contributes toward the development of benzoxazine industries.

The abuse of antibiotics in treating microbial infections has led to the emergence and prevalence of drug-resistant bacteria. Thus, the development of novel antibacterial materials is attracting increasing attention. Here, a series of flexible electrostatic hydrogels with excellent antibacterial ability were constructed using a mixture of nitric oxide (NO)-releasing nitrated chitosan (CSNO) and mesotetra(4-carboxyphenyl)porphine (TCPP) with salmon sperm DNA (ssDNA) solution. When cultured with gram-negative bacteria under solar simulator irradiation, TCPP-CSNOm-ssDNAnhydrogels released reactive oxygen species (ROS) and NO to produce peroxynitrite ions (ONOO−). ONOO−is efficient at killing bacteria, thereby improving the antimicrobial ability of photodynamic therapy against gram-negative bacteria. The hydrogels exhibited powerful antibacterial activity in vivowhen used to treat skin infections caused by drug-resistant bacteria, making them a promising candidate for clinical applications. A string of antibacterial hydrogels that release ROS and NO synergistically can bring new possibilities for effectively killing drug-resistant bacteria and be of great value in anti-infection wound dressings and other applications.

In the last three decades, carbon dioxide (CO2) emissions have shown a significant increase from various sources. To address this pressing issue, the importance of reducing CO2emissions has grown, leading to increased attention toward carbon capture, utilization, and storage strategies. Among these strategies, monodisperse microcapsules, produced by using droplet microfluidics, have emerged as promising tools for carbon capture, offering a potential solution to mitigate CO2emissions. However, the limited yield of microcapsules due to the inherent low flow rate in droplet microfluidics remains a challenge. In this comprehensive review, the high-throughput production of carbon capture microcapsules using droplet microfluidics is focused on. Specifically, the detailed insights into microfluidic chip fabrication technologies, the microfluidic generation of emulsion droplets, along with the associated hydrodynamic considerations, and the generation of carbon capture microcapsules through droplet microfluidics are provided. This review highlights the substantial potential of droplet microfluidics as a promising technique for large-scale carbon capture microcapsule production, which could play a significant role in achieving carbon neutralization and emission reduction goals.

This paper deals with the leader-follower finite-time consensus problem for multiagent systems with nonlinear dynamics via intermittent protocol. The topological structure of the followers is undirected or balanced digraph. Different from most existing works concerning nonlinear dynamics (satisfies Lipschitz continuity), the nonlinear dynamics of each agent satisfies Hölder continuity in this paper. In light of the finite-time control technique, the intermittent control protocol is designed to reach accurate leader-follower finite-time consensus. It is justified that the leader-follower finite-time consensus can be realized if the length of communication is greater than a critical value by using limit theory. Finally, two numerical examples are exhibited to validate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Primary biliary cholangitis (PBC) is an autoimmune disease involving dysregulation of a broad array of homeostatic and metabolic processes. Although considerable single-nucleotide polymorphisms have been unveiled, a large fraction of risk factors remains enigmatic. Candidate genes with rare mutations that tend to confer more deleterious effects need to be identified. To help pinpoint cellular and developmental mechanisms beyond common noncoding variants, we integrate whole exome sequencing with integrative network analysis to investigate genes harboring de novomutations. Prominent convergence has been revealed on a network of disease-specific co-expression comprised of 55 genes associated with homeostasis and metabolism. The transcription factor gene MEF2Dand the DNA repair gene PARP2are highlighted as hub genes and identified to be up- and down-regulated, respectively, in peripheral blood data set. Enrichment analysis demonstrates that altered expression of MEF2Dand PARP2may trigger a series of molecular and cellular processes with pivotal roles in PBC pathophysiology. Our study identifies genes with de novomutations in PBC and suggests that a subset of genes in homeostasis and metabolism tend to act in synergy through converging on co-expression network, providing novel insights into the etiology of PBC and expanding the pool of molecular candidates for discovering clinically actionable biomarkers.

The properties of ceramic shells determine the casting quality in the investment casting process. Research results regarding the addition of various fibers to the shell suggest that the green strength, the fired strength, and even the permeability of the fiber-reinforced shell are increased. In this work, the hot strength and the retained strength of a shell reinforced by dispersed polypropylene fibers were investigated based on previous research. The results show that the maximum hot strength of the shell prepared via the conventional method (CM) and the preimmersion slurry method (PSM) for a fiber content of 0.6 wt% increase by 58.31% and 37.94% compared with those of the fiber-free shell, respectively. When the fiber content is less than 0.6 wt%, the retained strength of the shell prepared via the PSM is close to that of the shell obtained through the CM. Through X-ray diffraction and energy-dispersive X-ray spectroscopy, it was found that the hot strength and the retained strength of the fiber-reinforced shell primarily consist of a glass-phase in the matrix and holes left by the burned-out fibers. Besides, the retained strength of the fiber-reinforced shell prepared via the PSM was also affected by the carbonized fiber. The permeability of the shell with the fiber additive is improved.

The all-DC delivered offshore wind farm has great potential in power engineering application due to its advantages in large capacity and long distance delivery. Considering the cost and reliability, the all-DC wind farm can be connected to the onshore grid via the Line-Commuted Converter High Voltage Direct Current (LCC-HVDC) but more interaction may also occur in the form of sub-/super-synchronous oscillations. In order to analyze the stability issue of such offshore wind farm system, the DC-port impedance are firstly established for the aggregated wind farm based on permanent magnet synchronous generator (PMSG) and LCC-inverter by using the harmonic linearization method, where the power outer loop cascaded by the current inner loop of PMSG wind farm and the phase-lock loop (PLL) of the LCC inverter are taken into consideration. Furthermore, the interaction between these two subsystems is analyzed based on the stability criteria through their impedance characteristics. Finally, simulation results are conducted by reproducing the time-domain oscillation in order to evaluate the effectiveness of impedance model for the all-DC delivered offshore wind farm system.

In China, the high-penetrated doubly-fed induction generators (DFIG) wind turbine (WT) is undergoing the centralized collection and long-distance line-commutated converter (LCC) high voltage DC (HVDC) transmission. In such high-penetrated renewable generation and transmission system, the dynamics of power electronics become dominant over the conventional synchronous generator so that its modeling and stability analysis needs re-examining. However, the interaction among interconnected wind farm, and LCC-HVDC, and weak grid remains unclear but may easily incur the stability issue. This paper firstly builds the wind farm model by aggregating each WT and collection transmission with the consideration about the frequency coupling. The double Fourier transform is further used to derive the mapping function in frequency-domain relates the current and voltage harmonics between DC and AC sides of the 6-pulse LCC converter, based on which the analytical 6-pulse LCC-HVDC impedance from AC side can be theoretically developed. The developed analytical impedance of DFIG wind farm with LCC-HVDC transmission system is verified by the comparison with the frequency sweeping simulation results and the oscillation reproduction in MATLAB/Simulink. The major parameter influence on system impedance characteristics is finally analyzed and compared in detail.

The connected vehicle (CV) technology has emerged in recent years. This article studies cooperative startup control of heterogeneous CVs in a platoon. First, from the perspective of cooperative tracking of heterogeneous multiagent systems, a hierarchical finite-time control framework is established, which consists of an upper-level interactive observer layer and a lower-level local controller layer. By separating neighboring information interaction from local dynamics control, the proposed framework allows to design upper-level observers and lower-level local controllers separately. Second, by introducing a potential function related to the consensus and observing errors, a distributed finite-time observer is designed for each CV to observe a startup reference trajectory available for only part of the CVs. Third, a distributed local finite-time controller is designed for each CV to track its observed startup reference trajectories. Within the proposed framework, finite-time observing and tracking of the startup reference trajectory are strictly proved to guarantee cooperative startup control. Numerical simulations are carried out to demonstrate the effectiveness of the proposed methods.

As a renewable chemical, diphenolic acid (DPA) has attracted immense interest in bio‐based polymer science. However, its application for polybenzoxazines is limited due to decarboxylation, that is, the release of CO2during the curing reaction of benzoxazine. In this study, the amidation strategy of converting DPA to diphenolic amides (DPAM) was demonstrated to solve this problem while simultaneously improving the thermal properties of polybenzoxazine. DPA was amidated by separately using four amines (hexamine, cyclohexylamine, furfurylamine, and aniline), then reacted with furfurylamine and paraformaldehyde to synthesize their benzoxazine monomers. By using TGA and DMA, all amide‐containing polybenzoxazines were found to exhibit excellent thermal stabilities. Among all of the benzoxazine resins, poly(DFA‐fa), which was obtained from amidation with furfurylamine, exhibited the highest glass transition temperature (Tg) of 310°C and a decomposition temperature (Td10) of 406°C. Furthermore, a possible post‐curing reaction mechanism was proposed to explain the outstanding thermal performance of poly(DFA‐fa) resin. This study proposes an innovative strategy to solve the decarboxylation of DPA‐based polymers, which is of significance for high‐performance bio‐based polymers.

As-cast beryllium-aluminum (Be-Al) alloy exhibits a coarse microstructure with pore defects due to a large solidification interval, greatly limiting its mechanical properties. In this research, the relationship between laser surface remelting process and microstructure and hardness of as-cast Be-Al-Sc-Zr alloy was established. The experimental results demonstrated that a pore-free refined microstructure of remelted layer was obtained by controlling the parameter of effective laser energy input. The microstructure of as-cast Be-Al-Sc-Zr alloy consisted of equiaxed grains with Al phase forming a continuous frame wrapping Be phase, which was significantly refined in the remelted zone (from 25 μm to 2 μm). The Vickers hardness in the remelted zone (approximately 210 HV) was approximately 3 times that of as-cast Be-Al-Sc-Zr alloy. Analysis of the Vickers hardness and the Be phase size showed a good agreement with a Hall-Petch equation. In addition, transmission electron microscopy (TEM), auger electron spectroscopy (AES) and X-ray diffraction (XRD) analysis evidenced that Sc and Zr elements formed a single blocky phase Be13(Scx,Zr1-x), which was also greatly refined from 8 μm to 1.5 μm in the remelted zone. The results obtained in this study indicate that the laser surface remelting allowed refining the microstructure and further strengthening the Vickers hardness of Be-Al-Sc-Zr alloy.

In order to prepare high strength plaster molds for investment casting, polypropylene and aluminum silicate hybrid fibers of contents 0.50 wt% were introduced into powder mixture of gypsum and mullite. The effects of different ball milling times on strengths of plaster molds were investigated in this work. To this end, modified mullite and gypsum powder were mixed and treated by ball milling for 2.0–8.0 min. The hybrid fibers were added to the solid mixture to prepare reinforced plaster molds with high strengths. The green, fired, and residual strengths of plaster mold specimens were all tested. The results showed a positive effect of ball milling on the strengths of plaster molds, in which strength could effectively be improved by raising the ball-milled time regardless of the presence or absence of the fiber. The strength increased by at least 29.7% when compared to un-milled specimen. However, the ball milling time should not be too long since exceeding 6.0 min resulted in a slow declining trend of the strength of the plaster molds until reaching a stable plateau. Shorter ball milling periods could refine the crystal size of refractory materials. For green specimens, the morphology of plaster crystal changed from short rods to fine needles and then to column crystals as milled time rose, promoting changes in strength. The microscopic morphologies of fired specimens were slightly impacted by the increase in milling time. Overall, ball milling periods of 4.0–6.0 min were identified as optimum for fiber-reinforced plaster molds. These findings look promising for future preparation of solid shell for investment casting.

This paper is devoted to the dynamic event-triggered consensus problem of general linear multi-agent systems under fixed and switching directed topologies. Two distributed dynamic event-triggered strategies, where internal dynamic variables are involved, are introduced for each agent to achieve consensus asymptotically. Compared with the existing static triggering strategies, the purposed dynamic triggering strategies result in larger inter-execution times and less communication energy among agents. In addition, neither controller updates nor triggering threshold detections require continuous communication in the purposed control strategies. It is also proven that the Zeno behavior is strictly ruled out under fixed and switching directed topologies. Finally, the effectiveness of the theoretical analysis is demonstrated by numerical simulations. [ABSTRACT FROM AUTHOR]

The use of fibers as additives to increase the strength of investment casting shell has yielded some significant results. Here, polypropylene fiber of length 6 mm was added to the shell by airflow placement fiber method, and the three different processes [the conventional method, preimmersion silica sol method, and preimmersion slurry method (PSM)] were used to prepare fiber-reinforced shell based on better fiber dispersion; the strength of shell with 0.2–1.0 wt% fiber addition was tested and compared. The experimental results show that the green strength and fired strength of shell with 0.4–0.6 wt% fiber addition reached the maximum in the three processes. The shell prepared by PSM exhibited a higher strength than the other two methods with the same amount of fiber addition; the maximum green strength was 36.9% higher than the strength of fiber-free shell. Combined with the surface morphology of placement fiber and fracture surface morphology of shell, the factors affecting shell strength and interface bonding characteristics were analyzed.

In this work, plaster molds for investment casting, reinforced with short polypropylene fibers, were prepared and their properties and fracture surface features were investigated. Fiber contents ranging from 0.10 to 0.50 wt% were introduced into a powder mixture of gypsum and mullite (ratio of 3:7) as reinforcements in order to prepare thin-walled plaster molds with high strength and permeability. The strength of green and fired plaster mold specimens was tested, the permeability was also tested, and their fracture surfaces were observed by scanning electron microscopy (SEM). The results show that the strength of the molds increases initially and then decreases with increasing fiber content. The green flexural strength of the specimens containing 0.20 wt% polypropylene fibers reached the maximum, c.a. 1.94 MPa, increased by 36.6%, and particularly, there was a slight increase in their fired strength, a maximum value of 0.45 MPa, in comparison with the fiber-free specimen. This low increase in the fired strength the reinforced specimen will produce a favorable effect on the collapsibility of shells in the casting cleaning process. In addition, the fired permeability of fiber-reinforced fired specimens exhibited significant enhancement, compared to that of the unreinforced ones. With increasing fiber content, the permeability of specimens increased from 8.6 to 11.5%. The improvement of green permeability was limited substantially. SEM observations indicate that the failure of the green specimens is a result of brittle fracture of the plaster substrate and/or fiber debonding from the matrix during loading. On the contrary, in fired specimens, the failure occurs by holes in the plaster substrate resulted from fiber ablation in the matrix during the firing process. The arrangement of polypropylene fibers can also affect the fracture behavior of molds. This proposed approach can reduce mold thickness without loss of strength and provide defined judgment basis for fracture features.

Several works have shown that graphene materials can effectively regulate the double-stranded DNA (dsDNA) structures and are used to remove antibiotic resistance genes in the environment, during which the morphology of the graphene surface plays a key role. However, the mechanism of how different graphene surfaces interact with dsDNA is poorly documented. Here, the interactions of dsDNA with defective graphene (D-Gra) and pristine graphene (P-Gra) have been explored by molecular dynamics simulations. Our data clearly showed that both D-Gra and P-Gra were able to attract dsDNA to form stable bindings. However, the structure evolutions of dsDNA are distinctly different. In detail, D-Gra can initiate quick unwinding of dsDNA and cause significant structural disruption. While for P-Gra, it demonstrated a much weaker capability to disrupt the dsDNA structure. This difference is due to the strong electrostatic interaction between defects and DNA nucleotides. Nucleotides can be highly restricted by the defect while the other parts of dsDNA could move along the transverse directions of D-Gra. This effectively introduces a “pulling force” from the defect that causes the breaking of the hydrogen bonds between dsDNA base pairs. Such force finally leads to the serious unwinding of dsDNA. Our present findings could help us to better understand the molecular mechanism of how the dsDNA canonical B-form was lost upon adsorption to graphene. The findings of the key roles of defects on graphene are beneficial for the design of functional graphenic materials for biological and medical applications through nanostructure engineering.

Developments in spinning systems have triggered revolutions ranging from bioengineering tissue scaffolds to emerging smart wearable fabrics, but the structures of the spinning fibers are usually limited by intrinsic channel configurations and the “dead” nozzle’s geometry. In contrast, natural living systems, such as a spider spinning apparatus, use a “live” gate to coordinate microstructures via shearing and expanding at both axial and radial directions. Herein, for the first time, we introduce a dynamic liquid gating effect in artificial systems to mimic the spinning in biological organisms. Theoretical modeling and experimental regime diagram demonstrate that the topographies and microstructures of the fibers self-evolve after passing through the liquid gate and they could be tuned over a wide range, which successfully exceeds the limits of current “dead” spinning channels. In particular, fibers with a periodic spindle-knot structure self-evolve from a water gate and show fast directional water collecting and intelligent sensing ability. The liquid gating design not only sheds new light on fiber structure control in multiple spatiotemporal dimensions but also contributes to the development of high-performance fibers with sophisticated functions.

Recently, the development of modern vehicles has brought about aggressive integration and miniaturization of on-board electrical and electronic devices. It will lead to exponential growth in both the overall waste heat and heat flux to be dissipated to maintain the devices within a safe temperature range. However, both the total heat sinks aboard and the cooling capacity of currently utilized thermal control strategy are severely limited, which threatens the lifetime of the on-board equipment and even the entire flight system and shrink the vehicle’s flight time and range. Facing these thermal challenges, the USA proposed the program of “INVENT” to maximize utilities of the available heat sinks and enhance the cooling ability of thermal control strategies. Following the efforts done by the USA researchers, scientists in China fought their ways to develop thermal management technologies for Chinese advanced energy-optimized airplanes and spacecraft. This paper elaborates the available on-board heat sinks and aerospace thermal management systems using both active and passive technologies not confined to the technology in China. Subsequently, active thermal management technologies in China including fuel thermal management system, environment control system, non-fuel liquid cooling strategy are reviewed. At last, space thermal control technologies used in Chinese Space Station and Chang’e-3 and to be used in Chang’e-5 are introduced. Key issues to be solved are also identified, which could facilitate the development of aerospace thermal control techniques across the world.

The frequent oscillations in the weak-grid-tied permanent magnet synchronous generator (PMSG) wind farms can severely deteriorate the power system security. The impedance-based method is widely applied but limited to optimize the system, where the PMSG is regarded as a black box and only the external output characteristics are reflected. In this article, a novel impedance-based analytical approach is proposed to analyze the weak-grid-tied PMSG wind farms from a control interaction perspective, to complement existing studies. The shaping effect of the interactions among various controllers on the impedance of PMSG is analyzed, including the phase-locked loop (PLL), the voltage control loop and the current control loop. Based on the analytical analysis, an optimization method is then devised to appropriately design the parameters of the voltage control loop and improve the system stability margin. Time-domain simulation results in Matlab/Simulink verify the efficacy of the proposed method. The outcome of this study can provide useful guidance on control designs for PMSG-WTs in weak grids.

Oscillation issues of permanent magnet synchronous generator (PMSG) wind turbines (WTs) have an increasingly significant impact on grid stability, especially with their increased generation capacity. However, the machine-side model (MSM), involving machine-side converter (MSC) and generator, is generally simplified as an ideal voltage source to comprising the impedance model of a PMSG-WT used for stability analysis, thus causing deficiency in describing the machine dynamics. Besides, the impedance-based method considering the PMSG-WT as a black box only describes the system from the external output characteristics; as such, the shaping effect of the internal controllers on the impedance model has not been fully studied yet. This article proposes the impedance model of PMSG-WTs consisting of generator, MSC, dc-bus and grid-side converter (GSC) for more accurate stability analysis. Furthermore, based on the general Nyquist criteria (GNC) and eigenvalue sensitivity analysis method, the shaping effect of the controllers inside GSC and MSC on the PMSG external impedance is quantitatively studied. The influence of the MSM on the system stability is investigated by comparing with the simplified model through extensive simulation studies.

In this study, a novel preparation route of shells for investment casting was proposed. To this end, hydroxypropyl methylcellulose (HPMC) was used as fiber dispersant, and its influences on rheological behaviors of slurry and strength of shell were studied. The addition of carbon fibers with different lengths and concentrations was also explored. The results suggested that suspension and viscosity of the slurries with HPMC were higher than those prepared without HPMC due to dispersion and tackily effects of HPMC on fibers and slurries. The fibers were found uniformly dispersed in the slurry, and fracture shell was uniformly distributed in the shell thanks to the presence of the dispersant, leading to enhanced shell strength. In addition, higher firing temperatures led to denser shell and superior strength.

Irradiation-induced damage of binderless nanoporous-isotropic graphite (NPIG) prepared by isostatic pressing of mesophase carbon microspheres for molten salt reactor was investigated by 3.0 MeV He+irradiation at room temperature and high temperature of 600 °C, and IG-110 was used as the comparation. SEM, TEM, X-ray diffraction and Raman spectrum are used to characterize the irradiation effect and the influence of temperature on graphite radiation damage. After irradiation at room temperature, the surface morphology is rougher, the increase of defect clusters makes atom flour bend, the layer spacing increases, and the catalytic graphitization phenomenon of NPIG is observed. However, the density of defects in high temperature environment decreases and other changes are not obvious. Mechanical properties also change due to changes in defects. In addition, SEM and Raman spectra of the cross section show that cracks appear in the depth range of the maximum irradiation dose, and the defect density increases with the increase of irradiation dose.

A parameter estimation method, called PMCMC in this paper, is proposed to estimate a continuous-time model of the term structure of interests under Markov regime switching and jumps. There is a closed form solution to term structure of interest rates under Markov regime. However, the model is extended to be a CKLS model with non-closed form solutions which is a typical nonlinear and non-Gaussian state-space model(SSM) in the case of adding jumps. Although the difficulty of parameter estimation greatly prevents from researching models, we prove that the nonlinear and non-Gaussian state-space model has better performances in studying volatility. The method proposed in this paper will be implemented in simulation and empirical study for SHIBOR. Empirical results illustrate that the PMCMC algorithm has powerful advantages in tackling the models.