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In order to study the stability of deep surrounding rock during the excavation of new main shaft in Xincheng gold mine, a construction method suitable for large section ultradeep shaft is proposed. A series of analyses were carried out in this study, including the in situ stress test, stress response of surrounding rock disturbance, deformation and failure characteristics, and numerical simulation. Based on the above analysis, the stability control method of surrounding rock in the process of deep excavation of the new main shaft is proposed. The results show that (1) the maximum principal stress of deep surrounding rock of new main shaft is horizontal stress, and the surrounding rock of the shaft has strong rock burst tendency after excavation; (2) the influence range of the deep shaft excavation disturbance is 6.4 times the shaft radius, in which the temporary support should be strengthened to avoid the influence of excavation disturbance on the stability of shaft wall rock; (3) the failure shape of surrounding rock of the deep shaft excavation was “ear” failure, and the failure depth was not more than 2.5 m; (4) after replacing the original “one-excavation and one-masonry” construction with “three-excavation and one-masonry” construction, the temporary support span of the main shaft was adjusted to 12 m, which can make the subsequent concrete shaft wall in the state of “no pressure bearing or slow low pressure bearing,” and the lining compressive safety coefficient was increased to 1.98, which meets the safety requirements.

A modified vertical braiding machine and closed annular axis mandrels with a special-shaped cross section were used to braid annular axis preforms under four different technical parameters. After measuring the braiding angles and yarn spacing of the braided preform in different areas of the mandrels, it was found that the braiding angle increased by 20.9% and the yarn spacing decreased by 19.8% when the speed of the yarn carrier was doubled. The braiding angle decreased by 31.1% and the yarn spacing increased by 28.6% when the rotation speed of the mandrels was doubled. The results show that the rotation speed of the mandrel has a slightly greater influence on the braiding angle and the yarn spacing. By using the modified braiding machine to braid the annular axis preforms, multi-layer continuous braided preforms can be achieved on compact equipment. And the structure of the annular axis braided preforms can be changed by changing the technical parameters.

With the development of bonded Nd–Fe–B magnets, modifying epoxy resin (EP) binder has become a key factor to improve the properties of bonded Nd–Fe–B magnets. In this work, the magnetic properties, compressive strength, and microstructure of the bonded Nd–Fe–B magnets with diaminodiphenylmethane (DDM)-cured EP binder were systematically investigated. The results show that adding 20 wt% DDM to EP monomer maintains excellent magnetic properties while obtaining optimal temperature resistance and high compressive strength for magnets. Because the molecular structure of the DDM curing agent contains rigid groups, it can enhance the heat resistance and mechanical properties of the EP binder. In addition, fracture surface morphology observation reveals the bonding mechanism of DDM-EP bonded magnets and confirms the advantageous nature of DDM-EP binder for bonded magnets.

Incinerating agricultural residues to recover energy is a popular method for reducing solid waste pollution and resource waste caused by the huge amount of coconut petiole residues. However, this process not only has the risk of secondary air pollution, but also the added value of comprehensive utilization is not high. In this paper, coconut petiole residues were used as eco-friendly and economical raw materials to synthesize carbon dots (CCDs) via a simple hydrothermal method. Furthermore, given the important reference significance of Fe3+ concentration in assessing the quality of water environment and human body health, the obtained CCDs were utilized for Fe3+ detection. The prepared spherical CCDs with an average diameter of 1.39 nm and a carbon skeleton dominated by benzene ring structure have surface functional groups that endow them with good water solubility. The CCDs with a quantum yield of 1.39% emit strong blue fluorescence under ultraviolet radiation (365 nm), and show favorable fluorescence stability with excitation-dependent and concentration-dependent emission behaviors. Based on the synergetic effect of static and dynamic quenching, the CCDs exhibit favorable selectivity and detection sensitivity toward Fe3+ with a linear range of 0.005 to 0.2 mM and a detection limit of 2.3 μM, and also show the feasibility of Fe3+ detection in real water samples. This work is in favor of the high value-added conversion of coconut petiole residues. In addition, the development and use of bio-based CCDs as fluorescence sensors may be beneficial to monitoring and protecting public health and the environment.

The unburned H2 can be used to reduce NO emission in conventional TWC (three-way catalyst) for a hydrogen internal combustion engine when it works at equivalence ratio marginally higher than the stoichiometric ratio. To explore the effects and feasibility of this reaction, a Perfectly Stirred Reactor simulation model of TWC has been built with simplified mechanisms. Experiments on a 2.3 L turbocharged hydrogen engine are used to verify the conclusion. It shows that rising initial temperature accelerates the reduction of NO and the maximum reaction rate occurs at 400 °C temperature. The conversion efficiency of NO remains approximately 0 when temperatures below 300 °C. The efficiency reaches a peak value of approximately 98% with 400 °C and declines gradually. The unburned H2 to NO mixing ratio greater than 1.5 in TWC guarantees 100% NO conversion efficiency. The experiments indicate that the NOx concentration decreases from 2056 ppm to 41 ppm at the stoichiometric ratio after the treatment of TWC and NOx reaches 0 ppm with a rich ratio. Results also demonstrate that the suitable reaction temperatures for TWC locate in the range of 400 °C–500 °C. Therefore, if the temperature and the mixing ratio are appropriate, it can achieve zero emissions with NOx reduction by unburned H2 in conventional TWC for a hydrogen engine.

It is of great significance to study the brain structure and function in deep-tissue for neuroscience research and bio-medical applications because of the urgent demand for precise theranostics. Three-photon fluorescence microscopic (3PFM) bioimaging excited by the light in near-infrared IIb (NIR-IIb, 1,500–1,700 nm) spectral region is one of the most promising imaging techniques with the advantages of high spatial resolution, large imaging depth, and reduced scattering. Herein, a type of NIR-IIb light excitable deep-red emissive semiconducting polymer dots (P-dots) with bright 3PF and large three-photon absorption cross-section (σ3) at 1,550 nm was prepared. Then the P-dots were functionalized with polystyrene polymer polystyrene graft ethylene oxide functionalized with carboxyl groups (PS-PEG-COOH) and modified with NH2-poly(ethylene glycol) (PEG) to synthesis photochemically stable and biocompatible P-dots nanoparticles (NPs). Further the P-dots NPs were utilized for in vivo 3PFM bioimaging of cerebral vasculature with and without the brain skull under 1,550 nm femtosecond (fs) laser excitation. In vivo 3PFM bioimaging of the mice cerebral vasculature at various vertical depths was obtained. Moreover, a vivid three-dimensional structure of the mice vascular architecture beneath the skull was reconstructed. At the depth of 350 µm beneath the brain skull, 3.8 µm blood vessels could still be clearly recognized. NIR-IIb excitable P-dots assisted 3PFM bioimaging has great potential in accurate deep tissue bioimaging.

In vivo cortical optical imaging needs to overcome the scattering of skull. Compared to the traditional transcranial surgery-based open-skull glass window and thinned-skull preparation, chemical tissue optical clearing techniques can provide a skull-remained optical access to the brain while maintaining its original environment. However, previously demonstrated skull optical clearing windows could only maintain transparency for a couple of hours and hardly capable for high-resolution monitoring of awake animals. Here, we developed a convenient and easy-handling chronic skull optical clearing technique, named “Through-Intact-Skull (TIS) window”, which was compatible with long-term observation at high resolution, and yielded large imaging depth of 900 μm for cortical neurovascular visualization. In addition, our TIS window could monitor neuron activity in awake mice for a long term. Therefore, our bio-compatible and non-invasive TIS window is a new promising approach for intravital brain microscopy with great potential for basic research in neuroscience.

Integrating personal thermoregulation technologies into wearable textiles has enabled extensive and profound technological breakthroughs in energy savings, thermal comfort, wearable electronics, intelligent fabrics, and so forth. Nevertheless, previous studies have suffered from long-standing issues such as limited working temperature, poor comfort, and weak reliability of the textiles. Here, we demonstrate a skin-friendly personal insulation textile and a thermoregulation textile that can perform both passive heating and cooling using the same piece of textile with zero energy input. The insulation textile material is composed of biomaterial microstructured fibers that exhibit good thermal insulation, low thermal emissivity, and good dyeability. By filling these microstructure fibers with biocompatible phase-change materials and coating them with polydimethylsiloxane, the insulation textile becomes a thermoregulation textile that shows good water hydrophobicity, high mechanical robustness, and high working stability. The proposed thermoregulation textile exhibits slow heating/cooling rates with improved thermal comfort, offering feasible and adaptive options for personal cooling/heating scenarios and enabling scalable manufacturing for practical applications.

In spinning, sizing agent makes originally rigid glass filament yarn soft, smooth, reduces mechanical wear, and alleviates static electricity. In order to produce “stronger, thinner, and more uniform” E(Electronic) fiberglass cloth, the sized filament yarn is required to have good strand integrity and uniform belt-like shape. Currently, the sizing effect can only be evaluated artificially according to the image of cross section or longitudinal section of yarns. The goal of the paper is to find an objective evaluation method for sizing effects on strand integrity and performance of belt-forming of E-glass filament yarn. The image of cross section of yarn is captured by Keyence VK-X110 and analyzed by Image-Pro Plus to obtain the central position and diameter of each filament. The threshold of fiber spacing is set to determine whether filaments are clustered in group. The area of outer enveloping convex polygon containing all the clustered filaments is calculated and fiber-filling rate is calculated accordingly. By using the least square method, the minimum rectangle containing all groups of filaments is obtained to describe the basic contour of yarn cross section. The outer envelope polygon is divided into several equal parts to calculate the coefficient variation of thickness distribution and yarn distribution. These objective values well reflect the strand integrity and feature of belt-forming of yarn, and are consistent with the subjective evaluation. Rank order method is used to compare the sizing morphology of the yarns based on the values. A standard is also suggested for objective grade assessment of sized E-Glass yarns.

At present, there are many methods to measure the diameters of filaments in E-glass yarn, but only the average diameter is reported, which cannot reflect all the filaments in the yarn. The methods based on physical principle are not intuitive, the data based on the longitudinal fiber diameter image measurement method are not comprehensive, the observation on the cross-section image of yarn based on slice-making is time-consuming and labor-intensive, and requires manual measurement or self-developed software application. In this article, Keyence VK-X110 3D laser morphometry microscope was used to quickly obtain the cross-section image of glass filament yarn without making a slice of E-glass yarn, and Image-Pro Plus was used to measure all the filaments' diameters in the yarn automatically. The measurement data and analysis show that under the condition of completely processing all the filaments' image, minor axis of filament cross-section is approximate to the filament diameter. This method is not only able to verify whether glass filament yarn meets the quality criteria of ASTM D578-00, but also provides the diameter distribution of all the filaments in an E-glass yarn. In addition, the data support more comprehensive evaluation standard for the quality of glass filament spinning.

Catalytic oxidation of formaldehyde (HCHO) at ambient temperature is an effective method for indoor HCHO removal. In this study, Ni/Co-Layered double hydroxides (LDHs) with different molar ratios were successfully synthesized via a one-step hydrothermal method. Their structure and morphology were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET)-specific surface area, X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR), respectively. The catalytic activity results show that Ni/Co-LDHs with the Ni/Co ratio of 1:2 exhibited enhanced activity for HCHO decomposition. The removal efficiency of indoor HCHO was up to 99.7% at ambient temperature, and it remained highly stable without any obvious deactivation even after a reaction time of 800 min. The abundant hydroxyl groups were favorable for catalytic activity, which could not only enrich the adsorption of HCHO on the surface of catalysts, but also directly react with HCHO to obtain CO2 and H2O. Moreover, the redox cycles of Ni3+/Ni2+ and Co3+/Co2+ would provide more reactive oxygen species and therefore promote catalytic reaction. This work can provide a new insight into LDH-based catalysts for low-concentration HCHO removal in practical application.

As an organic binder for bonded Nd-Fe-B magnets, epoxy resin (EP) has poor heat resistance but good moisture resistance, while sodium silicate (SS) has poor moisture absorption but better heat resistance and corrosion resistance. In order to improve high temperature stability and decrease moisture absorption of bonded Nd-Fe-B magnets, EP/SS composites were applied as the binder to prepare bonded Nd-Fe-B magnets. The magnetic properties, moisture absorption, corrosion resistance, compressive strength and microstructure of composite bonded magnets were investigated. The results show that EP/SS bonded magnets can obtain excellent magnetic properties at room temperature, and even useable magnetic properties a thigh temperature environments at 200 °C. EP/SS composite binder effectively improves heat resistance and corrosion resistance of bonded Nd-Fe-B magnets, and reduces the hygroscopic properties. The molecule of sodium silicateis rigid and keeps it original shape at high temperature environments. In addition, SS in composite binder improves the mobility of the magnetic powders during the pre-pressing process, which makes the magnetic powders attain a more regular structure. These two factors will increase the mechanical properties. Moreover, sodium silicate in the composite binder can also cover the surfaces protecting the magnetic powders from oxidation and corrosion. EP in composite binder can cover SS surface to reduce the water absorption of SS as epoxy is a hydrophobic material. The EDX analysis shows that the composite binder has accumulated in the gaps of the magnet powders, which not only improves heat resistance and corrosion resistance, but also increases the mechanical properties. Therefore, EP/SS composite binder endows bonded Nd-Fe-B magnets excellent comprehensive properties.

The pre-chamber sparkplug mode can increase the combustion velocity because it can induce the turbulent jet into the cylinder. Higher combustion velocity can increase the brake thermal efficiency and decrease the knock tendency for hydrogen engines. To explore the effect of pre-chamber sparkplug mode on the combustion characteristics of the hydrogen-air mixture, different equivalence ratios, initial pressures and temperatures were selected to study in a constant volume combustion chamber working with pre-chamber sparkplug mode and normal sparkplug mode. The results showed that the pre-chamber sparkplug mode can accelerate the combustion velocity, increase maximum combustion pressure and decrease the combustion duration at all initial conditions. The maximum combustion pressure of pre-chamber sparkplug mode occurred at the equivalence ratio of 1.0 while it occurred at the equivalence ratio of 1.2 with normal sparkplug mode, which means pre-chamber sparkplug mode can increase the higher brake thermal efficiency and power. The combustion intensity of pre-chamber sparkplug mode was bigger than 1 and the biggest value occurred at the equivalence ratio of 0.6. Moreover, the combustion intensity of pre-chamber sparkplug mode was higher with lean equivalence ratios than that of rich equivalence ratios. Increasing the initial pressure can increase maximum combustion pressure and combustion velocity obviously for pre-chamber sparkplug mode, which was different from the normal sparkplug mode. The initial temperatures had little impact on the combustion intensity. These results showed the pre-chamber sparkplug mode was more suitable to be used in the boosting hydrogen engines to improve the performance.

A new approach employing scattering parameters (SPs) and genetic algorithm (GA) (SP-GA) is proposed for modelling conducted electromagnetic interference (EMI) noise source impedance. Based on the principle of SPs, the source impedance is measured through transmission and reflection parameters from a vector network analyser when the circuit is shorted and loaded with noise source impedance, respectively. Moreover, amplitude-frequency performance and phase-frequency performance are optimised by using GA, and therefore the equivalent resistance, capacitance, and inductance are attained following the usual formula of the phase and amplitude of source impedance. This work made contribution for the design of the conducted EMI filter.

Herein, we report on $\beta$-Ga$_{\mathbf{2}} \mathbf{O} _{\mathbf{3}}$ thin films grown on 4H-SiC (0001) substrates by Low pressure chemical vapor deposition (LPCVD). The influences of growth temperature on the crystal quality, optical properties, surface morphology of $\beta$-Ga$_{\mathbf{2}} \mathbf{O} _{\mathbf{3}}$ films were investigated using X-ray diffraction (XRD), UltravioletVisible (UV-Vis) Scanning Spectrophotometer, Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM). It was found that the surface morphology, grain size and strain of the $\beta \mathbf{Ga} _{\mathbf{2}} \mathbf{O} _{\mathbf{3}}$ thin films could obviously be influenced by the growth temperature in the range from 600 to $800 ^{\circ}\mathrm{C}$. The XRD results indicate that $\beta$-Ga$_{\mathbf{2}} \mathbf{O} _{\mathbf{3}}$textbf thin films were preferentially along the (201) oriented. At $750 ^{\circ}\mathrm{C}$, it is found that the $\beta$-Ga$_{\mathbf{2}} \mathbf{O} _{\mathbf{3\, }}$film with relatively high crystal quality. Geometrical epitaxial relationship between the $\beta$-Ga$_{\mathbf{2}} \mathbf{O} _{\mathbf{3\, }}$ (201) film and 4H-SiC (0001) substrate is revealed as $\beta$-Ga$_{\mathbf{2}} \mathbf{O} _{\mathbf{3}}$ $[010]\vert \vert 4\mathrm{H}-$SiC [1 –1 0] and $\beta$-Ga$_{\mathbf{2}} \mathbf{O} _{\mathbf{3}}$ $[102]\vert \vert 4\mathrm{H}-$SiC [1 1 0]. The lattice mismatch along $\beta$-Ga$_{\mathbf{2}} \mathbf{O} _{\mathbf{3}}$ [0 1 0] and $\beta \mathbf{Ga} _{\mathbf{2}} \mathbf{O} _{\mathbf{3}}$ [1 0 2] direction are 0.98% and 6.5%, respectively.

A micro soldering method based on micro gripping was developed to improve strength between bonding pad and wire. The designing and working principle of micro soldering set-up were based on micro gripper and microscopic vision guided motion of soldering iron tip. Strength comparative experiments between unsoldered and soldered bonding joints were conducted to demonstrate the bonding strength improvement brought by micro soldering procedure. X-ray microscopic computed tomography (CT) scanning results show maximum void diameter in the soldered binding joint is 97.905 µm.

This paper presents the fabrication and characterization of a MEMS micro-tweezers system based on precise welding. It can be used in picking and placing a variety of micro parts such as MEMS devices and solder particles. The gap between the tips of micro-tweezers is 500um and the width of the cantilever is 100um. A micro-box fabricated by welding is used to control the closing and opening of the tweezers. The closing force of the tips can achieve 200mN, and by changing the size of the tips and the actuating distance, the closing force can be well controlled. The micro-tweezers can be used manually or installed in the micro-manipulation systems to make the experiment process easy to operate and more precise.

The purpose of this paper is to present a technique for burst detection, localization, and cross-sectional area quantification based on the damping of fluid transients. The Fourier componen...

Bonded neodymium iron boron (Nd-Fe-B) magnets with excellent properties were prepared by using waterborne-epoxy resin/sodium silicate composite binder (W-EP/SS). The results show that this composite binder can endow the bonded magnets with high temperature resistance as well as strong corrosion resistance. In addition, the compressive strength of W-EP/SS bonded magnet is higher than other types of bonded magnets. W-EP/SS composite binder has excellent homogeneity, which can coat the magnetic powders uniformly during mixing and curing, and therefore forms a protective thin film on the surface of the magnet to prevent thermal oxidation under high temperature conditions as well as corrosion during chemical treatments. Moreover, the W-EP/SS composite binder, which combines the toughness of epoxy resin with the rigidity of sodium silicate, endows bonded magnets better mechanical properties. It is attributed to the co-existence of Si-O-Si and C-O-C network structure in the W-EP/SS. Therefore, it is expected that W-EP/SS composite binder will provide a broader application prospects for future bonded magnets.

Half-Grouted Sleeve Connection (HGSC) is extensively applied in the Prefabricated Concrete (PC) structures. The performance of the PC structures after fire has become an interesting research topic. However, the post-fire mechanical behaviors of the HGSC are still an issue that needs to be studied in depth. The experimental results of twelve HGSC specimens with concrete cover under static tension after 25 °C to 600 °C are presented in this paper. In the experiments, the post-fire HGSCs' failure mode is just rebar tension fracture, not bonding failure. The properties, such as strength, elongation, ductility, and elastic modulus were analyzed, and the failure mechanism, elongation and bonding slip, influence of concrete cover, bonding behaviour of HGSC after high temperature were discussed. It was found that some post-fire tensile properties of the HGSC were obviously affected by the peak temperature and the concrete cover.

A novel die sorter based on mechanical gripper was developed for picking and placing diced terahertz Schottky barrier diodes (SBD). The designing and working principle of die sorter are based on flexible hinge and linear-actuator. Dimensions of dies gripped by the sorter can be as small as 100 µm * 50 µm* 15 µm without damage to its air-bridge. For flipping upside down dies, the rotation motion was obtained by rotating linear actuator about its shaft. It is demonstrated that the placement accuracy of the sorter can achieve less than 9.5 µm and 3.0 µm in x-y direction respectively.

Dimensions of high frequency dies are typically less than 50 µm * 200 µm. It requires a micron scale adhesive dots dispensing method to the bonding area for micro assembly. In this paper, electrochemical-polishing and picosecond laser micro-machining were used to prepare such novel dispensing head. These needle-like dispensing heads with tip diameter of 5 µm can achieve 20 µm adhesive dot far smaller than 100 µm produced by standard industry equipment. The dispensing module was integrated into a custom-made motion stage with microscopy system to achieve higher dispensing accuracy.

Metal oxide and metal oxide composites have drawn substantial attention owing to their potential as substitutes for noble metal catalysts for the oxidation of HCHO. However, there are several challenges in the development of their structures and morphologies to maximize their catalytic performance. Herein, an effortless and controllable strategy is reported for the synthesis of metal oxide composite catalysts by a mixed-metal approach and calcining bimetal MOFs [MnCo-BDC-DABCO], resulting in highly dispersed MnCoOx nanoparticles encapsulated by N-doped carbon. Subsequently, a series of MnCoOx/CN catalysts with different molar ratios of Mn/Co was applied for the oxidation of HCHO. The metal oxide composite exhibited better catalytic activity and lower apparent activation energy than the single metal oxide. 100 ppm of HCHO could be totally converted into CO2 and H2O at a temperature as low as 80 °C on the Mn2Co1Ox/CN catalyst. With a lower concentration of HCHO (∼10 mg m−3), this catalyst demonstrated enhanced catalytic efficiency and superior stability at room temperature. Additionally, it maintained approximately 100% conversion for 24 h and remained exceptionally stable even after three consecutive rounds of testing. The structures of the catalysts were confirmed via N2 adsorption and desorption, TEM, H2-TPR, XPS and in situ DRIFTS measurements to clarify their superb catalytic performance. The characterization results indicate that the growth of nanoparticles in Mn2Co1Ox/CN was hindered, generating small particles embedded in carbon with a high specific surface. Furthermore, the improved reducibility together with sufficient surface reactive oxygen species may be responsible for their excellent catalytic activity and stability. This MOF-templated strategy affords a practical way to prepare cost-effective and efficient metal oxide catalysts for application in the purification of indoor air.

The phenol formaldehyde (PF), a kind of heat-resistant binder, was used to prepare bonded Nd–Fe–B magnets via mold pressing. The magnetic properties, compressive strength, and microstructure of the magnets were systematically investigated. The magnetic measurements show that PF binder endows Nd–Fe–B magnets excellent magnetic properties. Moreover, the magnets can keep the original shape and exhibit usable magnetic properties at 200 °C. With increasing binder content, the compressive strength of the magnets reach 253.6 MPa with 4 wt.% PF binder, which is 14 times higher than that of epoxy resin bonded Nd–Fe–B magnets. In addition, the reason of high compressive strength was investigated. The main chain of PF binder molecule contains rigid structure like benzene rings, which can form hard cross-linking network structure in the gaps of magnetic powders making the bonded magnets with high strength. Further fracture surface morphology observation and energy dispersive X-ray analysis reveal that liquid PF binder can permeate into gaps between the magnetic powders during the process of warm-molding and exert excellent bonding effect. Two mechanisms of action can endow PF/Nd–Fe–B magnets excellent mechanical strength and heat resistance.

Macroscopic hysteresis loops and microscopic magnetic moment distributions have been determined by 3-D model for Co nanowire with various easy axis deviations from applied field. It is found that both the coercivity and the remanence decrease monotonously with the increase of easy axis deviation as well as the maximum magnetic product, indicating the large impact of the easy axis orientation on the magnetic performance. Moreover, the calculated angular distributions and the evolution of magnetic moments have been shown to explain the magnetic reversal process. It is demonstrated that the large demagnetization field in the two ends of the nanowire makes the occurrence of reversal domain nucleation easier, hence the magnetic reversal. In addition, the magnetic reversal was illustrated in terms of the analysis of the energy evolution.

Microstructure and magnetic properties of hot deformed SmCo5 nanocrystalline magnet prepared from amorphous precursors are investigated. Hot pressed magnet as a precursor of the hot deformed magnet is amorphous. After hot deformation process, the SmCo5 magnet with 85% height reduction exhibits CaCu5 crystal structures and the strong c-axis textures. Moreover, the hot deformed SmCo5 magnet bears magnetic properties of $H_{\mathrm{ ci}} = 31.4$ kOe, $M_{r} = 6.42$ kG, $(BH)_{\max} = 10.1$ MGOe, and the remanence ratio of the magnet is as high as 0.87 due to the strong c-axis textures. In addition, fracture morphology shows that grains of the hot deformed magnet are plate shaped with an average grain size of 200 nm in thickness and 800 nm in diameter. Furthermore, the grain size of the magnet from transmission electron microscopy (TEM) observation has a good agreement with the scanning electron microscopy results. The TEM results also show that a lot of Sm-rich Sm-Co precipitate particles with a size less than 50 nm. These precipitate particles could act as pinning sites leading to high coercivity.

Nickel-rich layered oxide and graphite–SiOx are regarded as promising electrode materials for high energy density lithium ion cells. It is significant to illustrate the degradation mechanism related to the aging process of nickel-rich layered oxide cathode and graphite–SiOx anode in full cell. In this study, the as-prepared pouch cell with LiNi0.88Co0.09Al0.03O2 as cathode material and graphite–SiOx as anode material has been proved with three aging stages according to the capacity retention changes in behavior. The aging process of the pouch cell is studied by non-destructive electrochemical methods. And then the pouch cells at different aging stages are disassembled and the cell components are studied by electrochemical characterizations for reassembled electrodes and physico-chemical analysis techniques. In the result, the cathode degradation is slight and as a minor factor for the degradation of the whole cell, and the anode deterioration is worse and as the main factor for the degradation of the whole cell. The organic and inorganic composition changes of the solid electrolyte interphase (SEI) induce the aging behavior differences of the three stages, and the reversible lithium loss, electrochemical polarization and active material shedding are mainly responsible for the three stages, respectively.

Half grouted sleeve connection is widely used in joining rebars in precast concrete structures. However, its mechanical behaviors at elevated temperatures remain to be a topic with little research. This paper presents experimental results of 12 half grouted specimens and 12 single rebars under static tension at different temperatures. The tensile properties of half grouted sleeve connection were found to be directly affected by the temperature, and some characteristics are different from that of the rebar. The results showed that the half grout sleeves exhibited two types of failure, namely rebar fracture and rebar pullout due to bonding failure. The mechanical properties of specimens were similar to that of single rebars. When the temperature elevated, the failure mode and rebar breakpoint location may change. The bonding length that would be sufficient at room or low temperature, becomes insufficient at 600 °C. Suggestions about the bond length are given to avoid rebar pull out from the grout due to bond failure at elevated temperature.

Owing to the great influence of surface passivation on DC and RF performance of InP-based HEMTs, the DC and RF performance of InAlAs/InGaAs InP HEMTs were studied before and after passivation, using an ultra-thin 15 nm atomic layer deposition Al2O3 layer. Increase in Cgs and Cgd was significantly limited by scaling the thickness of the Al2O3 layer. For verification, an analytical small-signal equivalent circuit model was developed. A significant increase in maximum transconductance (gm) up to 1150 mS/mm, drain current (IDS) up to 820 mA/mm and fmax up to 369.7 GHz was observed, after passivation. Good agreement was obtained between the measured and the simulated results. This shows that the RF performance of InP-based HEMTs can be improved by using an ultra-thin ALD-Al2O3 surface passivation.

Fluorescent carbon dots (FCDs) have attracted tremendous attention in biological applications. The short-wave infrared (SWIR, 900–1700 nm) spectral range is considered as a novel optical tissue window due to low photon scattering. In this work, we investigated the fluorescence characteristics of FCDs based on the SWIR spectral range. SWIR emissions were observed from FCDs for the first time, when long-wavelength excitation (e.g. longer than 731 nm) was adopted. Wavelength-tunable two-photon fluorescence could also be obtained from the FCDs, under 1000–1560 nm SWIR femtosecond (fs) excitation. Interestingly, when an fs excitation wavelength as long as 1560 nm was adopted, two typical nonlinear optical signals, namely two-photon fluorescence and third harmonic generation (THG), could be observed. Based on the one-photon SWIR fluorescence, FCDs were successfully utilized for in vivo sentinel node mapping and tumour imaging. Under SWIR fs excitation, FCD-assisted two-photon fluorescence microscopy realized deep-tissue imaging of zebrafish embryos and the brain neuron networks of mice. SWIR excited and emitting FCDs have potential as fluorescent probes for deep-tissue and high-contrast functional bioimaging and related applications in the future.

Collective epithelial behaviors are essential for the development of lumens in organs. However, conventional assays of planar systems fail to replicate cell cohorts of tubular structures that advance in concerted ways on out-of-plane curved and confined surfaces, such as ductal elongation in vivo. Here, we mimic such coordinated tissue migration by forming lumens of epithelial cell sheets inside microtubes of 1–10 cell lengths in diameter. We show that these cell tubes reproduce the physiological apical–basal polarity, and have actin alignment, cell orientation, tissue organization, and migration modes that depend on the extent of tubular confinement and/or curvature. In contrast to flat constraint, the cell sheets in a highly constricted smaller microtube demonstrate slow motion with periodic relaxation, but fast overall movement in large microtubes. Altogether, our findings provide insights into the emerging migratory modes for epithelial migration and growth under tubular confinement, which are reminiscent of the in vivo scenario., Collective epithelial behaviours are studied in vitro in the context of flat sheets but a system to mimic tubular systems is lacking. Here, the authors develop a method to study collective behaviour in lumenal structures and show that several features depend on the extent of tubular confinement and/or curvature.

Microfluidics has been the key component for many applications, including biomedical devices, chemical processors, microactuators, and even wearable devices. This technology relies on soft lithography fabrication which requires cleanroom facilities. Although popular, this method is expensive and labor-intensive. Furthermore, current conventional microfluidic chips precludes reconfiguration, making reiterations in design very time-consuming and costly. To address these intrinsic drawbacks of microfabrication, we present an alternative solution for the rapid prototyping of microfluidic elements such as microtubes, valves, and pumps. In addition, we demonstrate how microtubes with channels of various lengths and cross-sections can be attached modularly into 2D and 3D microfluidic systems for functional applications. We introduce a facile method of fabricating elastomeric microtubes as the basic building blocks for microfluidic devices. These microtubes are transparent, biocompatible, highly deformable, and customizable to various sizes and cross-sectional geometries. By configuring the microtubes into deterministic geometry, we enable rapid, low-cost formation of microfluidic assemblies without compromising their precision and functionality. We demonstrate configurable 2D and 3D microfluidic systems for applications in different domains. These include microparticle sorting, microdroplet generation, biocatalytic micromotor, triboelectric sensor, and even wearable sensing. Our approach, termed soft tubular microfluidics, provides a simple, cheaper, and faster solution for users lacking proficiency and access to cleanroom facilities to design and rapidly construct microfluidic devices for their various applications and needs.

Nanoparticle-assisted near-infrared (NIR) bioimaging and two-photon fluorescence microscopy (TPFM) are two important technologies in biophotonic research. In this work, we synthesize the dye named 2-(4-bromophenyl)-3-(4-(4-(diphenylamino)styryl)phenyl)fumaronitrile (TPABDFN), which had a large two-photon absorption cross-section and bright NIR emission. The dyes were then encapsulated with poly(styrene- co -maleic anhydride) (PSMA), forming fluorescent nanoparticles. The TPABDFN-PSMA nanoparticles possessed high chemical and optical stability, good biocompatibility, as well as large two-photon absorption cross-section (5.56 × 10 5 GM). Furthermore, we combined NIR bioimaging and TPFM together, and utilized TPABDFN-PSMA nanoparticles as fluorescent contrast agents for two-photon excited NIR microscopic imaging, with a 1040 nm-femtosecond laser. In vivo angiography of mice ear and brain was performed. Due to the deep penetration capability of both 1040 nm-excitation and NIR emission light, a very large in vivo microscopic imaging depth (∼1.2 mm) was achieved. NIR emissive and biocompatible TPABDFN-PSMA nanoparticles have great potential in disease diagnosis and clinical therapies, where deep-tissue imaging is required.

Intumescent flame-retardant poly(1, 4-butylene terephthalate) composites with ammonium polyphosphate and a hyperbranched triazine charring-foaming agent were prepared through melt blending. The flame retardancy, pyrolysis behavior, and flame-retardant mechanism of flame-retardant poly(1, 4-butylene terephthalate) were investigated using flammability tests, cone calorimeter measurements, thermogravimetric analysis including evolved gas analysis, and residue analysis (Fourier transform infrared and scanning electron microscopy). The results showed that the intumescent flame retardant with the appropriate ammonium polyphosphate/hyperbranched triazine charring-foaming agent mass ratio (4/1) could significantly improve the flame retardancy of poly(1, 4-butylene terephthalate), and the highest Limiting Oxygen Index value and UL-94 V-0 rating was reached. The peak heat release rate and total heat evolved remarkably decreased, respectively, by 84% and 76% corresponding to poly(1, 4-butylene terephthalate). Thermogravimetric analysis results showed the synergistic effect between ammonium polyphosphate and hyperbranched triazine charring-foaming agent could enhance the char formation ability of composites. The results of gaseous products and residue char structure analysis indicated intumescent flame retardant influenced the decomposition behavior and promoted the formation and accumulation of phosphorous/azotic and polyaromatic char possessing high graphitization degree, which exerted a condensed-phase flame-retardant effect on the flame-retardant composites.

The harmful cyanobacteria blooms which usually form in spring and summer, cause global eutrophication of freshwater and coastal marine ecosystems. This study tried to utilize cyanobacteria as a raw material to produce biological poly(vinyl)alcohol-based films. Cyanobacteria was firstly modified with poly(ethylene glycol), guanidine hydrochloride, carboxymethyl cellulose and 3-glycidoxypropyltrimethoxysilane as plasticizer, modifier, toughening agent and coupling agent, respectively. And then the modified cyanobacteria was introduced to poly(vinyl)alcohol and cellulose nanofibers/poly(vinyl)alcohol matrix to improve the barrier properties of poly(vinyl)alcohol to light and water. Compared with poly(vinyl)alcohol and cellulose nanofibers/poly(vinyl)alcohol films, the obtained cyanobacteria/poly(vinyl)alcohol and the cyanobacteria/cellulose nanofibers/poly(vinyl)alcohol composites exhibit better resistance to light and water. More interestingly, we found that after adding cyanobacteria, the poly(vinyl)alcohol-based films present better barrier properties to blue-violet light and red light. In adddition, introducing cyanobacteria into poly(vinyl)alcohol or cellulose nanofibers/poly(vinyl)alcohol matrix increases the surface roughness and contact angle to water of the composites.

In order to prepare a good radiation shielding concrete with a proper setting time and a high strength, the hydration properties of cement with boron gangue were investigated by the methods of XRD, isothermal microcalorimetry, TG/DSC, and FTIR. The results demonstrated that it was mainly related to the insoluble matter CaB2O4·4H2O and Ca(H2BO3)2·4H2O that boron gangue could severely inhibit the cement hydration. Boron gangue made a significant retardation on Portland cement hydration with the form of BO33− and BO45−, which caused an obvious retardation of C3A and C3S hydration with an insoluble coat and a low solubility of calcium ion in the solution. Therefore, it is important and necessary to take into consideration the chemistry of borates in aqueous and the kind of cement-based or cementitious materials used for radiation shielding concrete with boron or boron compounds, especially for the materials with a high content of C3A and C3S.

Vasculature architecture of the brain can provide revealing information about mental and neurological function and disease. Fluorescence imaging in the second near-infrared (NIR-II) regime with less light scattering is a more promising method for detecting cortical vessels than traditional visible and NIR-I modes. Methods: Clinically approved dye indocyanine green (ICG) was used for NIR-II fluorescence imaging. Here, for the first time, we developed two NIR-II fluorescence microscopy systems for brain vasculature imaging in macaque monkeys. The first is a wide-field microscope with high temporal resolution for measuring blood flow velocity and cardiac impulse period, while the second is a high spatial resolution confocal microscope producing three-dimensional maps of the cortical microvascular network. Both were designed with flexibility to image various cortical locations on the head. Results: Here, ICG was proved to have high brightness in NIR-II region and an 8-fold QY increase in serum than in water. We achieved cerebrovascular functional imaging of monkey with high temporal resolution (25 frames/second) with wide-field microscope. The blood flow velocity of capillaries can be precisely calculated and the cardiac impulse period can be monitored as well. In vivo structural imaging of cerebrovasculature was accomplished with both high spatial lateral resolution (~8 µm) and high signal to background ratio (SBR). Vivid 3D reconstructed NIR-II fluorescence confocal microscopic images up to depth of 470 μm were also realized. Conclusion: This work comprises an important advance towards studies of neurovascular coupling, stroke, and other diseases relevant to neurovascular health in humans.

This paper presents a temperature insensitive current reference for SerDes application using SiGe BiCMOS technology. Modified zero temperature coefficient (ZTC) characteristic of MOS transistor is proposed and implemented in this design. Process variation effects caused by mismatch and temperature drift are discussed and minimized. Implemented in 0.18 μm SiGe BiCMOS technology, test have shown that an average current sensitivity of 20 ppm/○C (-15 to 130○C) is achieved with 3 V power supply.

In this paper, a mechanics based analytical truss model is proposed to predict the shear strength and deformation of conventionally reinforced coupling beams with span-to-height ratios less than 1.75 (referred to as short coupling beams). The model considers the yield of only parts of stirrups, and its load path is composed of a direct main strut connecting the compression zones at both ends of the beam and secondary struts balancing with stirrups. By satisfying the compatibility condition at the intersection node of the struts, the assignment of the applied shear load in the main and secondary struts, as well as the shear load-transverse displacement relationship of the beam, are determined. The shear strength predictions by the truss model are compared with test results of 37 conventional reinforced short coupling beams, which shows that it can accurately predict the shear strength with a coefficient of variation (COV) of 0.052, while the predictions provided by ACI 318-19 and GB 50010-2010 are relatively inaccurate (the COVs are 0.19 and 0.21, respectively). In addition, the skeleton curves of 27 short coupling beams are calculated by the truss model, and the results show that the predictions are in good agreement with the test results. In order to simplify the calculation, a simplified model is proposed based on the refined truss model. Although the accuracy of the simplified model is slightly reduced (the COV is 0.071), it is still significantly higher than those of the design codes. Based on the simplified model, a standardized design method, which indirectly considers the beam deformation capacity, is provided for practical shear design.