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The graphene-based composites was prepared by the oxidation of graphene nano-platelets. The characterization results of thermogravimetric analysis (TGA) and Fourier transform infrared spectrum (FT-IR) indicated that acid treatment can generate abundant functional groups on the surface of graphene. The determined equilibrium adsorption capacity of FGN for lead was 57.765 mg/g, which is higher than that of many currently reports. The adsorption process was completed within 40 min and the adsorption isotherms confirmed to Langmuir classical isotherms models.

Carbonate, tight sandstone, and shale reservoirs have many pore types, and the relationship between the porosity and elastic parameters is extremely discrete due to the complex pore shape. This paper presents a method for predicting reservoir pore types based on pore shape substitution. The pore shape substitution allows for accurately characterizing the changes in the elastic properties of the rock with the changes in pore shape, assuming there are no changes in terms of minerals, porosity, or fluids. By employing a multiple-porosity variable critical porosity model, the effective pore aspect ratio could be inverted from the velocities of the rock. To perform pore shape substitution, we could replace the effective pore aspect ratio with another pore aspect ratio or increase/decrease the volume content of different pore shapes. The reservoir pore types could be evaluated by comparing the differences in the reservoir velocities before and after the substitution of the pore shape. The test results pertaining to the theoretical model and the well logging data indicated that the pore shape substitution method could be applied to characterize pore types in terms of separating the effects of the pore shapes from the effects of the minerals, porosity, or fluids on the velocities.

Conductive self-healing hydrogels and related soft sensor devices are gaining extensive attention from academia to industry because of their impacts on the lifetime and ergonomic design of artificial skins and soft robotics, as well as health monitoring systems. However, so far the development of such a material has been limited considering performance and availability. In this work, we developed composite hydrogels of acrylamide, polyacrylamide, dialdehyde-functionalized poly(ethylene glycol) and conductive carbon black through an interpenetrating polymer network strategy. After optimizing the composition ratio, the resultant hydrogel exhibited self-healing reversibility mechanically and electrically when cut and self-healed. We used 1H NMR and FT-IR spectroscopy to determine the self-healing mechanism of the system, thus demonstrating that the cooperative effect of the dynamic covalent and noncovalent interactions contributes to the self-healing capability of the gel. Rheology, scanning electron microscopy and light-emitting diode circuits were carried out to examine its macroscopic and microscopic properties, making it possible to apply in soft and conformable electronics.

The development of Surface Enhanced Raman Scattering (SERS) promotes the wide application of Raman spectroscopy in chemical and biomolecular detection. SERS detection relies on analytes in close contact with the metallic surface, and therefore direct molecular trace detection in the liquid phase is difficult. In this paper, static liquid phase SERS detection was performed simply using a capillary without pre-functionalization. Gold nanoparticles (AuNPs) with an optimized size ensure localized surface plasmons in resonance with the exciting laser light. Grazing incidence and multimode interference in the capillary ensure that the longitudinal Raman signal is effectively excited and accumulated. An enhancement factor as high as 108 and a detection limit of 10−9 M of crystal violet in aqueous solution have been achieved.

In view of the significant performance improvement of unfilled epoxy insulators by direct fluorination, and the fact that all spacers in SF 6 gas insulated systems are alumina-filled epoxy composites, to promote the application of the method for improving the performance of epoxy spacers, in this paper, alumina-filled epoxy (composite) and unfilled epoxy (pure) samples were prepared with the same formulation and process as those for epoxy spacers. The pure and composite epoxy samples were fluorinated under the same conditions, and comparative studies were performed on their surface physicochemical characteristics and properties. IR analysis and SEM imaging show no obvious influence of alumina particles on the fluorination of the epoxy matrix under the used fluorination conditions, while many nanoparticles and agglomerates appear on the surface and large microsized particles in the SEM imaging depth become less visible after the composite epoxy sample was fluorinated. Contact angle and electrical property measurements indicate that like the pure epoxy sample, surface hydrophilicity and surface conduction of the composite epoxy sample are also increased by the fluorination, while the increase in surface hydrophilicity or surface conduction is more significant or less significant, compared to the pure epoxy sample. All these are associated with the fluorination of the alumina particles and the interface change or reconstruction between the particles and the matrix.

Conductive hydrogels with stretchable, flexible and wearable properties have made significant contributions in the area of modern electronics. The polyacrylamide/alginate hydrogels are one of the potential emerging materials for application in a diverse range of fields because of their high stretch and toughness. However, most researchers focus on the investigation of their mechanical and swelling behaviors, and the adhesion and effects of the ionic liquids on the conductivities of polyacrylamide/alginate hydrogels are much less explored. Herein, methacrylated lysine and different alkyl chain substituted imidazole-based monomers (IMCx, x = 2, 4, 6 and 8) were introduced to prepare a series of novel pAMAL-IMCx-Ca hydrogels. We systematically investigated their macroscopic and microscopic properties through tensile tests, electrochemical impedance spectra and scanning electron microscopy, as well as Fourier transform infrared spectroscopy, and demonstrated that an alkyl chain length of the IMCx plays an important role in the designing of hydrogel strain sensors. The experiment result shows that the hexyl chains of IMC6 can effectively entangle with LysMA through hydrophobic and electrostatic interactions, which significantly enhance the mechanical strength of the hydrogels. Furthermore, the different strain rates and the durability of the pAMAL-IMC6-Ca hydrogel were investigated and the relative resistance responses remain almost the same in both conditions, making it a potential candidate for wearable strain sensors.

Surface-enhanced Raman scattering (SERS) has been widely used owing to its high sensitivity and rapid response. In particular, 3D SERS-active platforms greatly extend the interaction area and ensure the ability to directly detect trace amounts of molecules in liquids. A silver-coated capillary, with the ability of liquid sampling and light guiding, provides a new platform for high-performance SERS substrates. In this paper, the silver mirror reaction was used for coating silver on the outer wall of the capillary. PDMS was used as a coating material to protect the silver film. Because of the silver coating, Mie scattering and Raman scattering in the liquid channel can be refocused and reflected back which greatly reduces the propagation loss and extends the interaction length. An enhancement factor as high as 108 and a detection limit of 10−10 M of rhodamine 6G in aqueous solution have been achieved. Moreover, the SERS intensity is homogeneous across the end face of the liquid channel, with the relative standard deviation (RSD) value changing within 7%. The large area and high homogeneity greatly reduce the requirement of light coupling precision and liquid injection pressure. Using a common flange optical fiber connector, the capillary can be simply connected and aligned with a multimode fiber with a detection limit of 10−8 M. The experiment results show great potential for the development of an optofluidic integrated system in the future.

The supercritical carbon dioxide (SCO2) Brayton cycle is one of the most promising power cycles due to its high efficiency, compactness and environmentally friendliness. The centrifugal compressor is a key component of small and medium SCO2 Brayton cycles, and its efficiency has a significant impact on the cycle efficiency. Since the required electric load of power cycles always fluctuates over the year, the SCO2 compressor will operate away from its design point and the narrow stable operating range of a compressor is always a restriction. In this paper, the variable-geometry method, which refers to the combination of a variable inlet-guide-vanes and variable diffuser vanes is proposed for the operating range extension of SCO2 compressors. A set of one-dimensional (1D) loss correlations has been found to accurately predict various losses of the SCO2 compressor components. Based on the 1D thermodynamic model, two programs with internal MATLAB codes coupled with the NIST REFPROP database have been developed for preliminary optimization design and off-design performance predictions of the variable geometry SCO2 compressor. The contributions from the variable-inlet prewhirl and variable diffuser vanes to the shifts of the surge line and choke line are discussed in this paper. The results show the variable-geometry SCO2 compressor has a superior performance at off-design conditions and a wider operating range.

Strainburst, defined as a burst that occurs on the periphery of tunnels, is always associated with intact and hard brittle rocks and high geo-stress. In practical engineering, the prevention of strainburst by bolting does not achieve the desired effects. Deep insight into the strainburst process and mechanisms under bolt support conditions is necessary to ensure safe underground construction. In this study, strainburst characteristics under bolt support conditions were investigated using a true-triaxial rockburst testing system, which was equipped with an acoustic emission monitoring system. High-speed cameras were also used to capture the ejection failure process. Two indicators, namely kinetic energy and maximum decibel, were used to comprehensively evaluate the rockburst intensity. In addition, characteristic stresses, failure mode and cracking mechanisms under different bolt spacing conditions were investigated. The test results demonstrated that rockburst is greatly affected by the bolt arrangement. Rockburst changes from the way occurring in the form of a local failure in weak area to the way striking the bolt position and even the overall free face with the decrease in bolt spacing. The use of the bolt increases the rockburst intensity, but the intensity decreases as the bolt spacing decreases. Characteristic stresses including crack initiation stress, crack damage stress and peak strength increase monotonously with the use of bolt and the decreasing bolt spacing. During the strainburst, tensile failure dominates the cracking process regardless of bolt spacing; however, with the use of bolt and decrease in bolt spacing, tensile splitting near the free face become less obvious and the proportion of shear failure gradually increased.

A fluorographene sensing membrane on silicon nitride (Si3N4) for light-addressable potentiometric sensors (LAPS) is investigated. Three layers of monolayer graphene grown using low-pressure chemical vapor deposition (LPCVD) were transferred and stacked on a Si3N4 LAPS and then treated with CF4 plasma with a filter shielding. Clear fluorination of the 3-layer graphene is proven by studying the Raman spectrum, X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The pH sensitivity and linearity of this fluorographene sensing membrane are 56.8 mV/pH and 99.4%, respectively. The drift coefficient and hysteresis are 2.6 mV/h and 2.9 mV, respectively. This sensing performance is comparable to a Si3N4 sensing membrane. A significant negative bias shift in the photocurrent versus gate bias characteristics can be observed in the fluorographene sensing membrane, which could be explained by the fact that the work function increases owing to the dipole effect of carbon–fluorine bonds. A two-dimensional (2D) image of photocurrent measured in a pH 7 buffer solution for a sample with fluorographene and a Si3N4 sensing membrane on the same surface is generated by the scanning controlled by an X Y stage and LAPS measurement system. The high and the low photocurrents of the fluorographene and Si3N4 sensing membrane can be clearly distinguished in the static 2D pH image with an appropriate gate bias voltage. Through these experimental results, fluorographene is proven to be a suitable pH-sensing membrane. Further study on surface immobilization is suggested for biomedical targets in the future.

The metal oxidation of boiler tubes becomes one of the main factors which affect the safe operation of the utility boiler. And the rapid and accurate measurement and prediction of oxide scale accumulation is very necessary. The paper strengthens the stable magnetic field by the associated scale and finds the coupling relationship between the change of magnetic induction intensity and the corresponding scale accumulation in the tube. A new method for rapid non-destructive detection of scale is proposed. In order to improve the rapidity and robustness of the detection method, the Fletcher and Reeves (FR) conjugate gradient method is improved by finite scalar factor and dynamic step size, and the mean value error (MAE) is used respectively. The root mean square error is used. (RMSE), mean deviation (MBE) and Wilmot index (D) were used to validate the established measurement model. The results show that the improved nonlinear conjugate gradient method has good performance in detection accuracy and robustness, and has fast convergence characteristics.

Asphalt aging is one of the key factors affecting the service life of asphalt pavement. Asphalt materials are prone to irreversible performance degradation under ultraviolet (UV) irradiation. In this study, a ternary composite carbon nitride modifier (CN-Bi-Tr-DC) with excellent compatibility with asphalt binder was prepared. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and ultraviolet visible near infrared spectroscopy (UV–Vis-NIR) were used to characterize the micro morphology and light absorption rate of the modifier. The results showed that the long organic chains were successfully grafted onto the surface of the ternary composite carbon nitride modifier. In addition, the ultraviolet absorption rate of CN-Bi-Tr-DC is 65%. Dynamic shear rheometer (DSR) was used to investigate the high and low temperature performance and fatigue resistance of CN-Bi-Tr-DC modified asphalt. CMAI, G-RAI, ICO and ISO were used to evaluate the long-term aging performance of CN-Bi-Tr-DC modified asphalt. The test results demonstrated that the addition of CN-Bi-Tr-DC could improve the anti-ultraviolet aging performance of asphalt binder, and the improvement effect was most obvious when the content of CN-Bi-Tr-DC was 2–4%.

This study utilizes an innovative regenerative dual-evaporator organic Rankine cycle (RDORC) with R1234ze to recover solid bulk waste heat by using air as heat transfer medium. A comprehensive transient model for RDORC is constructed based on finite volume method. Furthermore, a novel coordinated feedback control system for RDORC including two PI controllers is proposed to remain turbine inlet main vapor and resupplied vapor superheat degrees constant. The transient behaviors of RDORC and simple ORC (SORC) are compared under external disturbances of heat source inlet temperature. The results indicate that under 10 °C step decrease disturbance, the RDORC presents a 0.5 °C larger undershoot and a 164s longer setting time of superheat degree than that of SORC. Compared with SORC, the exergy efficiency enhancement of RDORC increases from initial value 4.13% to final value 4.51% after the step disturbance. Under sinusoidal disturbance with amplitude of 10 °C in RDORC, the peak amplitude of turbine main vapor inlet pressure (3.6%) is far higher than that of turbine resupplied vapor inlet pressure (0.82%). Besides, under random disturbance with variance of 1, the system exergy efficiency and thermal efficiency fluctuate around the design values of 35.67% and 7.65% with maximum deviations of 2.2% and 0.37%, respectively.

Scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) are used to investigate the doping profile of saddle-fin (S-fin) devices in a 30-nm dynamic-random-access-memory (DRAM) technology. Due to the limited resolution of SCM, SCM cannot provide a clear doping profile of an S-fin array device. In the meantime, SSRM and focused ion beam milling during sample preparation provide an opportunity to obtain a 2-D and scanning line doping profile. The common-source region between two adjacent buried word lines is treated with an additional phosphorus (P) implantation with energy and dosage modification to have a doping profile modification in the array devices of DRAM product. With condition of the medium energy and high dosage in this additional P implantation, the row hammer effect of 30-nm DRAM could be minimized by the localized shielding effect from the electric field by a depletion effect. The junction profile of the additional P implantation is about 10 nm deeper than that of the control sample, as verified by SSRM and technology computer-aided design simulation. The experimental results of the doping profile can be used to support a mechanism of improvement of row hammer. The SSRM methodology proposed in this study could be used to optimize the doping profiles in DRAMs for future scaling technology.

We investigated the giant magneto-impedance (GMI) effect on ferrimagnetic insulator yttrium iron garnet (YIG) films and spheres, and the ferromagnetic resonance effect played a vital role. The GMI results were derived from the high-frequency measurements of a microwave transmission line loaded with YIG films and spheres. Our findings showed that there were obvious distinctions in the impedance of the transmission line loaded with single crystalline YIG samples depending on the external magnetic field, which indicates the significant GMI effect. The maximum GMI ratio as high as 256% was achieved, corresponding to a magnetic response of 8.8%/Oe. This study reveals that single crystalline YIG films are promising candidates for using as probe element in chip-scale magnetic sensors.

Focusing on the oblique frictional contact problem of hydrogel for soft robot, a numerical contact model is developed to analyze the nonlinear behaviors including local contact large deformation and friction effect of hydrogel soft material during oblique contact. Based on the constitutive relation of hyperelastic material, the updated free energy function of hydrogel is derived. The contact algorithm is given to compute the contact responses of both collinear contact example and oblique contact example. The applicability of classical Hertz contact theory is discussed. The influence of coefficient of friction on the stress distribution of contact zone and the contact states of contact surface are also investigated. The numerical results show that the material nonlinearity and the geometric nonlinearity (i.e. large deformation) of hydrogel lead to the invalidation of classical Hertz contact theory. For the oblique contact, the internal stress grads of hydrogel will be redistributed as the coefficient of friction increases. Meanwhile, the maximum stress position moves from underside to the contact surface. Two high stress zones occur inside and on the contact surface at the same time, respectively. Besides, when the coefficient of friction is smaller (i.e. μ < 0.05), for the collinear contact all contact points on the contact surface are in critical state from static friction to dynamic friction. But for the oblique contact, some contact points are always in stable static friction state.

Hybrid organic-inorganic lead halide perovskites (HOIPs) have appealed to researchers on account of excellent optoelectronic properties. Compared with films which possess grain boundaries, HOIPs single crystals with fewer defects behave excellent transport and recombination performances. In the family of HOIPs, single crystals of MAPbX3 (MA = CH3NH3 +, X = Cl, Br or I) are recognized as the most competitive candidates for optoelectronic applications. However, the photodetectors based on MAPbX3 have difficulties in detecting weak signals for lacking of gains without structure optimizations and extra energy transfer channels. In this study, taking advantage of MAPbBr3 single crystal (100) facets, planar metal-semiconductor-metal (MSM) photodetectors were fabricated with Au zigzag electrodes and modified Au nanoparticles (NPs) to realize localized Au surface plasmons (SPs). Compared to device without Au NPs, 2 times enhancement of photocurrent and responsivity have been achieved under 630 nm photon irradiation and 5 V bias. Furthermore, the surface metal structures can inhibit ionic migration to a certain extent. Potential mechanisms of the enhancements and suppressions are discussed in details to reveal the applications of this technique.

The row hammer effect has become a reliability issue that cannot be ignored in sub-30-nm dynamic random-access memory (DRAM) products because of the narrow isolation spacing between the array devices. Improving the row hammer effect via fabrication process optimization is first proposed in this paper. An additional phosphorus (P) implantation with energy and dosage modification applied in the common source area between two adjacent buried word lines of the access devices and energy adjustment of the well implantation are applied to provide a doping profile modification in the array device. With the proper implantation setting of the high energy and 2X dosage in the additional P implantation, a localized shielding effect from the electric field by a depletion effect could be used to reduce the chances of hammering gate-induced electrons in the channel leaking to the adjacent access device. This proposed mechanism could be supported by the experimental results of the doping profile. Therefore, the row hammer effect can be suppressed by up to 30% in normalized fail bit counts. This proposed methodology could be used in future generations to suppress the row hammer effect in DRAMs.

In many engineering applications, either the suppression or the enhancement of dehumidification is desired. If so, the dehydration in air-conditioned space can be solved, less condensation water pollution can be achieved, or the dehumidification process can be more efficient. In this study, the effects of various surface treatments were explored to enhance or suppress the condensation. It was found that optical observation to the appearance of water droplets was the best solution. A USB microscope is able to discover a droplet as small as 13 um in diameter. When the first droplet was found, the corresponding surface temperature was considered as the dew-point temperature in the circumstance. A cold-plate platform, which is cooled by cool water from a refrigeration circulator, was designed and established. The surface temperature can be regulated by settings of the refrigeration circulator. Tests of step-wise temperature drops were performed. The original surface was made of aluminum alloy Al-5083. Spin-coated, blasted, anodized, Teflon-coated, and polymer-coated surfaces were prepared on the same substrates. The results show that the polymer-coated surface exhibited an effective dew-point of 2.95°C higher than the original surface. On the other hand, the Teflon-coated surface exhibited an effective dew-point of 1.025°C lower than the original surface. In this study, a platform and methodology were established and further surface treatments can be explored in the future. Key words: Dehumidification, condensation, surface treatment, blasted, wettability

Now, electroscope has disadvantage of large quality, inconvenient operation, and it has low quality of accuracy, adaptability, reliability and cost performance. In this paper, a new method for the identification of electricity test is presented. It uses electrochromic material for equipment electricity identification of UHV power transmission and transformation. When the device is charged, the material will change color as the charged signal; while the device is not charged, the material will return to the original color. The material has advantage of low energy consumption, no radiation, apparent identity, repeated use. This paper adopted three kinds of materials such as tungsten trioxide material, Ag-Polybutene (hereafter referred to as PB) composite material and graphene-Polyamide (hereafter referred to as PA) for production making and test. The results show that these three kinds of material have electricity identification performance, the properties of graphene-PA composites were the best, and it has the development prospect as eletrochromism material used for equipment electricity identification of UHV power transmission and transformation.

The ventilation coefficients that represent the enhancement of mass transfer rate due to the falling motion of spherical hailstones in an atmosphere of 460 hPa and 248 K are computed by numerically solving the unsteady Navier–Stokes equation for airflow past hailstones and the convective diffusion equation for water vapor diffusion around the falling hailstones. The diameters of the hailstones investigated are from 1 to 10 cm, corresponding to Reynolds number from 5935 to 177 148. The calculated ventilation coefficients vary approximately linearly with the hailstone diameter, from about 19 for a 1-cm hailstone to about 208 for a 10-cm hailstone. Empirical formulas for ventilation coefficient variation with hailstone diameter as well as Reynolds and Schmidt numbers are given. Implications of these ventilation coefficients are discussed.

In this study, the transport theorem of phonons and electrons is utilized to create a model to predict the thermal conductivity of composite materials. By observing or assuming the dopant displacement in the matrix, a physical model between dopant and matrix can be built, and the composite material can be divided into several regions. In each region, the phonon or electron scattering caused by boundaries, impurities, or U-processes was taken into account to calculate the thermal conductivity. The model is then used to predict the composite thermal conductivity for several composite materials. It shows a pretty good agreement with previous studies in literatures. Based on the model, some discussions about dopant size and volume fraction are also made.

A new Li2O–SrO–Nb2O5–P2O5 glass system was prepared by a high-temperature alumina crucible, and structural characterization and optical properties were investigated. Proper content of Li2O and Nb2O5 was employed to replace partial SrO and P2O5 to improve the optical properties. It was observed that the enhancement of the refractive index from 1.75 to 1.85 is mainly due to the Nb2O5 content. An addition of Li2O significantly increases the optical transmittance; optical transparency can be enhanced from 60% to higher than 85% in the UV–visible region with addition of 20–40 mol% Li2O species. However, optical transmittance is monotonically decreased from about 90% to 80% under 10–30 mol% Nb2O5 addition. The 40P2O5–20Nb2O5–20SrO–20Li2O glasses demonstrate the optimum refractive index (n > 1.75) and high optical transparency (>80%) in the UV–visible region. Furthermore, the effect of Nb2O5 on the structural transition was focused on the (60 − y)P2O5–yNb2O5–20SrO–20Li2O vitreous system since the transition of FTIR spectra reveals that the Nb2O5 has more pronounced effect than Li2O in the glass network due to the higher covalent extent and electronegativity. Addition of Nb2O5 generates Nb–O bonds by dissociating P–O chains and results in the decrease in the intensity of the (PO2), (POP), and (PO3) absorption bands. The O1s-XPS analysis shows that Nb2O5 addition dissociates symmetric bridging oxygens in P–O–P bonding and forms asymmetric bridging oxygens in P–O–Nb and non-bridging Nb–O- bonds, in which octahedral [NbO6] unit is eventually substituted by [NbO4] tetrahedral unit in the Li–Sr–Nb phosphate glasses.

The melting temperature, microstructures, and mechanical properties of the Sn-Zn-0.5Ag-0.5Ga, Sn-Zn-0.5Ag-0.45Al and Sn-Zn-0.5Ga-0.45Al lead-free solders were investigated. The results indicate that the addition of 0.5 wt% Ag to the Sn-Zn based alloys destroy the eutectic structure and results in the formation of Ag-Zn compound and hypoeutectic structure. The variation in the microstructure lowers the UTS. By the addition of Al the UTS and elongation of the 0.5Ag-0.45Al alloy can be decreased due to the Al diffused to the interface of the Ag-Zn compound/Sn-Zn eutectic structure to form Al-Zn compound. The 0.5Ga-0.45Al alloy shows a typical eutectic structure with the light contract β-Sn and the darker needle-like phase, as well as a small amount of Al-Zn phase with a near diamond shape. Gallium uniformly distributes in the Sn matrix and Zn rich phases. The 0.5Ga-0.45Al solder had the highest UTS and elongation, while 0.5Ag-0.45Al had the lowest UTS and elongation. The results indicate that Ga and Al exhibits prominent influence on the microstructure as well as the mechanical properties of the solders.

The biodiesel content or blending ratio of a biodiesel fuel is crucial for the quality control and official regulation. A rapid ( −1 ) detection chamber composed of a hydrophobic electrode pair (two identical screen-printed carbon paste electrodes) to improve the data precision. In low frequency region ( n = 8) was useful to estimate the blending ratio of biodiesel ( r 2 > 0.98) with good resolution, reproducibility and thermal stability, which is important for the quality control and regulation of the eco-friendly fuel.

Antiosteoporosis gene-based drug development strategies are presently focused on targeting osteoblasts to either suppress bone loss or increase bone mass. Although siRNA/microRNA-based gene therapy has enormous potential, it is severely limited by the lack of specific cell-targeting delivery systems. We report an osteoblast-targeting peptide (SDSSD) that selectively binds to osteoblasts via periostin. We developed SDSSD-modified polyurethane (PU) nanomicelles encapsulating siRNA/microRNA that delivers drugs to osteoblasts; the data showed that SDSSD-PU could selectively target not only bone-formation surfaces but also osteoblasts without overt toxicity or eliciting an immune response in vivo. We used the SDSSD-PU delivery system to deliver anti-miR-214 to osteoblasts and our results showed increased bone formation, improved bone microarchitecture, and increased bone mass in an ovariectomized osteoporosis mouse model. SDSSD-PU may be a useful osteoblast-targeting small nucleic acid delivery system that could be used as an anabolic strategy to treat osteoblast-induced bone diseases.

The desulfurization (de-SO2) powders are a solid waste obtained from the sintering plants of the iron and steel industries. It is mostly landfilled due to its massive quanti ties and complicate compositions. A new utilization was developed in this study as a de-soil reagent for the treatment of tailings in the open-pit mines. In this paper, the de-SO2 powders were collected from a sintering plant using the semi-dry de-SO2 process. The chemical compositions of the de-SO2 powders were analyzed by titrations and the chemical phases were determined with a X-ray diffractometer (XRD). The size distribution was measured by a laser particle size analyzer. The micro-morphology was observed by a scanning electron microscopy (SEM). Furthermore, the interaction between the de-SO2 powder and the soil particle was studied.

The performance of vapor chambers, also known as flat heat pipes, was studied experimentally. Five vapor chambers with different vapor space heights were intentionally fabricated and tested. The hydraulic diameter ratio was created to be the dimensionless parameter to represent the variation of the vapor space height. The parameter was further used to derive the optimum vapor chamber height. It was found that the vapor chamber achieved the optimum design when the hydraulic diameter ratio of non wick vapor space to chamber interior was greater than 0.6. It is believed that the results are valuable for future vapor chamber design.

Electrospinning is investigated by many groups around the world for constructing fibrous tissue engineering scaffolds. Incorporating biomolecules such as growth factors in fibers is becoming common for enhancing the biological performance of electrospun scaffolds. However, biomolecules may lose bioactivity if they are exposed to organic solvent during electrospinning. In emulsion electrospinning, an aqueous biomolecule solution is emulsified and water-in-oil emulsions are then electrospun into core-shell structured fibers, with biomolecules being contained in the core of fibers, which helps to avoid biomolecule-solvent contact and also reduce the initial burst release. In this investigation, for a comparative study, poly (L-lactic acid) was made into solid and core-shell structured fibers via conventional electrospinning and emulsion electrospinning, respectively. The two electrospinning techniques and resultant fibers were compared in terms of processing parameters (polymer concentration, applied voltage, working distance, etc.) and fiber characteristics (morphology, diameter, structure, etc.). Solvent properties such as conductivity and volatility affected fiber morphology and diameter. The polymer concentration range usable for emulsion electrospinning was narrower than that for conventional electrospinning owing to changes in viscosity.

TiO 2 nanoparticle-coated nickel wires were produced by electrical heating in various nanofluid concentrations ranging from 0.01 to 1 wt.% with various processing heat fluxes from 0 to 1000 kW/m 2 . The experimental results demonstrated up to 82.7% enhancement on critical heat flux (CHF) in condition of coated nickel wire (processed in 1 wt.% with 1000 kW/m 2 ) boiling in pure water. The contact angle measurement revealed that the hydrophilic porous coating formed by vigorous vaporization of TiO 2 nanofluid in nucleate boiling regime enormously modified the wettability of heating surface consequently improving the CHF. Besides, it is evident that the coverage of nanoparticle deposition tended to become more complete as concentration and processing heat flux increased based on SEM and EDS analysis. The nanoparticles dispersed in base fluid exhibited little effect on CHF enhancement and could even hinder the percentage of CHF augmentation from boosting, which demonstrated that one could enhance CHF by using only small amount of nanoparticles just adequate to form surface coatings instead of preparing working fluid with great bulk. However, according to the boiling curves in all cases of coated nickel wires, it is supposed that the nucleate boiling heat transfer coefficient deteriorates as a result of thermal resistance resulted from the occurrence of nanoparticle deposition. In summary, the coated porous structure of nanoparticles leads to enhance CHF and to decrease boiling heat transfer coefficient.

This study investigated to eliminate the nitrogen load of sediment from Yangzhou ancient canal capping with an active barrier system (ABS) using two kinds of zeolite with five different coverage densities. For ABS capping with zeolite F1 when the zeolite dose is low (0.21 kg/m2 and 0.62 kg/m2), it is found that ABS failed to achieve good control in preventing N release in the entrophic sediments as total nitrogen (TN) concentrations of overlying water were increased to 3.76 mg/L and 3.13 mg/L, respectively after 16 days. However, when zeolite density was increased to 1.04 kg/m2, TN concentration of overlying water decreased to 1.94 mg/L and TN removal efficiency is up to 50% after 16 days. For ABS capping with zeolite F2 TN concentration of overlying water is reported to descend in both low dose and high dose series. It is found that zeolite F2 is unfit for remediation of sediments from ancient Canal in Yangzhou because the ability in preventing release of ammonia nitrogen from sediments is weak. A possible explanation is that microorganism attaching on surface of two zeoltes differs to cause large difference of removal capacity between zeolite F1 and zeolite F2. It is found that nitrification and denitrification is the principal pathway for the former one while nitrite accumulation appears in the latter. To sum up, the capacity of eliminating TN load by zeolite F1 is stronger than that by zeolite F2, the optimum capping density of zeolite F1 is 1.04 kg/m2.

The effects of adding cerium to lithium on the properties of lithium anode were studied in alkaline aqueous LiOH electrolyte at 30 °C. Self-corrosion hydrogen evolution rate at open circuit potential and electrochemical experiments show that the magnitude of hydrogen evolution rate is reduced obviously by adding cerium to lithium. As the content of Ce increases to 0.08 wt%, the inhibition efficiency reaches approximately 83.3%. SEM results show that the surface of Li–Ce alloy forms more compact and less porous film than that of pure lithium after discharge. XRD examination proves the presence of Ce(OH) 3 in the lithium-cerium alloy film besides LiOH and LiOH·H 2 O. It is suggested that Ce(OH) 3 plays a key role in inhibiting the hydrogen evolution and affecting discharge potential on the surface of lithium-cerium alloy anode in aqueous alkaline LiOH electrolyte.

The inhibition performance of alloy element Na and ethanol inhibitor on lithium anode in 4 mol/L LiOH alkaline aqueous electrolytes at 30 °C was investigated using hydrogen evolution rate measurement at OCP, polarization curve, electrochemical impedance spectroscopy and voltage-time curve. The results show that alloy element Na and ethanol have inhibition effect both on anodic and cathodic reaction, but single alloy element Na or ethanol can not play an effective inhibition role on anode; only co-adding of alloy element Na and ethanol can greatly enhance the effect of inhibiting hydrogen evolution, the inhibition efficiency exceeds 80%. In addition, the property of discharge is very unstable with only adding of alloy element Na, but this problem can be resolved by adding ethanol. XRD shows that Li and Na forms perfect solid solution.

Anodized composite films containing superfine Al 2 O 3 and PTFE particles were prepared on 2024 Al alloy using an anodizing method. The microstructures and properties of the films were studied by scanning electron microscopy, optical microscopy and X-ray diffraction. Friction wear tests were performed to evaluate the mechanical properties of the composites. Results indicate that the composite films with reinforced Al 2 O 3 and PTFE two-particles have reduced friction coefficients and relatively high microhardness. The friction coefficient can be as small as 0.15, which is much smaller than that of an oxide film prepared under the same conditions but without adding any particles (0.25), while the microhardness can reach as high as 404 HV. When rubbed at room temperature for 20 min during dry sliding friction tests, the wear loss of the film was about 16 mg, which is about the half of that of the samples without added particles. The synthesized composite films that have good anti-wear and self-lubricating properties are desirable for oil-free industrial machinery applications.

The superplastic behavior and deformation mechanism of a heat-resistant Al–Cu–Mg–Ag–Mn alloy prepared by ingot metallurgy was investigated by using optical microscopy, scanning electron microscopy and transmission electron microscopy. It is shown that the Al–Cu–Mg–Ag–Mn alloy shows good superplastic properties at temperatures higher than 450 °C and strain rates lower than 10 −2 s −1 . A maximum elongation-to-failure of 320% was observed at 500 °C and 5 × 10 −4 s −1 , where the corresponding strain rate sensitivity index m is 0.58 and the flow stress σ is 5.7 MPa. Microstructure studies revealed that the observed superplastic behavior resulted from severe grain elongation rather than grain boundary sliding. It is suggested that this phenomenon may provide a new concept for developing superplastic materials.

This article experimentally investigates the thermal performance of the vapor chamber module applied to the high-power light-emitting diodes in natural convection. The flat-plate-type vapor chamber and the lamp-type vapor chamber are provided to solve the heat dissipation problem of the high-power light-emitting diodes. The results show that the spreading resistance and the corresponding temperature difference of the flat-plate-type vapor chamber at 30 W are lower than those of the copper plate by 34% and 4°C, respectively, and are lower than those of the aluminum plate by 56% and 6°C, respectively. Compared with the copper and aluminum plates, the lamp-type vapor chamber at 15 W is reduced about 8% and 12% for the total thermal resistance, respectively. In addition, it is also about 3°C and 5°C lower for the central wall temperature of the lighting side, respectively. This study provides a new thermal management method to solve the heat dissipation of the high-power light-emitting diodes. Furthermore, th...

Electrospinning of poly(L-lactic acid) (PLLA) and gelatin separately to form nonwoven PLLA or gelatin nanofibrous membranes was investigated. Factors that could affect the fiber morphology and fiber diameter were studies for PLLA and gelatin, respectively. The polymer solution concentration was found to play a dominant role in the formation of defected or nondefected ultrafine fibers. Using a specially designed experimental setup with separate syringe pumps for polymer solutions and separate power supplies for high voltages for electrospinning, PLLA-gelatin bicomponent fibrous membranes were formed with PLLA fibers interweaving with gelatin fibers. Multicomponent fibrous scaffolds can be very useful for tissue engineering and/or controlled release applications.

Thermal wear of cast hot-forging die steel modified by rare earths(RE) was studied and compared with commercially used die steels. The function of RE and the mechanism of thermal wear of cast steel modified by RE were discussed. The results showed that with increasing content of RE, the wear rate of cast steel reduced at first and then increased. By adding 0.05% (mass fraction) RE, the cast hot-forging die steel with optimum thermal wear resistance was obtained, which was better than that of H13 and 3Cr2W8V. The large amount of coarse inclusions, (RE)2O2S, resulted from excessive RE, which obviously deteriorated thermal wear resistance. The mechanism of thermal wear of the modified cast die steel is oxidation wear and oxide fatigue delamination. The wear debris are lumps of Fe2O3 and Fe3O4.

The effects of Ce and Ti additions on the microstructures and mechanical properties of an Al-Cu-Mg-Ag alloy have been studied. It has been shown that either Ce or Ti can decrease the as-cast grain size of the Al-Cu-Mg-Ag alloy, increase the nucleation ratio for Ω phase as heterogeneous nucleation centers, inhibit the growth of Ω phase during aging, and thus increase the volume fraction and decrease the spacing of Ω phase. These microstructures increase the yield strength and tensile strength. However, if both Ce and Ti are added to the alloy, they form (Ce,Ti)-contained compounds and increase the grain size during casting, but have no effects on the nucleation and the growth of Ω phase during aging. The alloy containing both Ce and Ti has a relatively lower Vicks hardness and strength compared to the alloy containing either Ce or Ti.

In this study, Leidenfrost experiments were conducted for water, NaCl, and KCl aqueous solutions at atmospheric pressure. In our tests, a 1.1 g test liquid was gently deposited on a horizontal heated aluminum surface. The evaporation time at various surface temperatures was recorded and plotted as evaporation curves. To examine the relationship between bubble coalescence, dissolved salt and the Leidenfrost transition, test surfaces were fabricated with arrays of small holes serving as artificial nucleating sites. Cavity spacing is 1 mm or 2 mm. It is demonstrated that the dissolved salt increases the Leidenfrost temperature. Mechanisms associated the Leidenfrost transition, such as suppression of bubble coalescence, variation in properties and salt deposition during the initial liquid–solid contact, are explored and accessed.

A microfluidic chip is proposed to separate microparticles using cross-flow filtration enhanced with hydrodynamic focusing. By exploiting a buffer flow from the side, the microparticles in the sample flow are pushed on one side of the microchannels, lining up to pass through the filters. Meanwhile a larger pressure gradient in the filters is obtained to enhance separation efficiency. Compared with the traditional cross-flow filtration, our proposed mechanism has the buffer flow to create a moving virtual boundary for the sample flow to actively push all the particles to reach the filters for separation. It further allows higher flow rates. The device only requires soft lithograph fabrication to create microchannels and a novel pressurized bonding technique to make high-aspect-ratio filtration structures. A mixture of polystyrene microparticles with 2.7 μm and 10.6 μm diameters are successfully separated. 96.2 ± 2.8% of the large particle are recovered with a purity of 97.9 ± 0.5%, while 97.5 ± 0.4% of the small particle are depleted with a purity of 99.2 ± 0.4% at a sample throughput of 10 μl/min. The experiment is also conducted to show the feasibility of this mechanism to separate biological cells with the sample solutions of spiked PC3 cells in whole blood. By virtue of its high separation efficiency, our device offers a label-free separation technique and potential integration with other components, thereby serving as a promising tool for continuous cell filtration and analysis applications.

The microwave dielectric properties and the microstructures of (Mg1/2Co1/2)Al2O4 ceramics prepared by conventional solid-state route have been studied. The dielectric constant values (ɛr) saturated at 8.3–8.7. The Q × f values of 4500–107,300 GHz can be obtained when the sintering temperatures are in the range of 1480–1600 °C. The temperature coefficient of resonant frequency τf was not sensitive to the sintering temperature. The ɛr value of 8.75, Q × f value of 107,300 GHz, and τf value of −54 ppm °C−1 were obtained for (Mg1/2Co1/2)Al2O4 ceramics sintered at 1600 °C for 4 h. For applications of high selective microwave ceramic resonator, filter and antenna, (Mg1/2Co1/2)Al2O4 is proposed as suitable material candidate.

The effects of gallium additions on microstructures and thermal and mechanical properties of the Sn-9Zn solder alloys are investigated in this study. The results show that the melting temperature of the alloys decreases with the increase in the Ga concentration, while the pasty ranges of the alloys are simultaneously enlarged. By adding a 0.25–0.5 wt.% Ga element, the Sn-matrix region is slightly increased and the Zn-rich phase becomes slightly coarser; however, the overall microstructure is still very similar to that of the Sn-9Zn alloy. It is found that, when the Ga concentration is less than 0.50 wt.%, the ultimate tensile strength and elongation are maintained at the same values. The addition of a 0.25–0.50 wt.% Ga to the Sn-9Zn alloy also leads to small cup and cone fracture surfaces which exhibit near-complete ductile fracturing. With the addition being increased to 0.75 wt.%, larger cup and cone fractures are observed. The 1.00 wt.% Ga alloy has lower strength and ductility due to the coarser and nonuniform microstructures. However, the fracture surfaces of the 1.00 wt.% Ga alloy show partial cleavage and a partially dimpled fracture.

Microwave dielectric properties and microstructures of (Mg 1/2 Zn 1/2 )Al 2 O 4 ceramics prepared by conventional solid-state route have been studied. The dielectric constant values ( ɛ r ) saturated at 7.1–8.6. The Q × f values of 2000–95,000 GHz can be obtained when the sintering temperatures are in the range of 1480–1600 °C. The temperature coefficient of resonant frequency τ f was not sensitive to the sintering temperature. The ɛ r value of 8.6, the Q × f value of 95,000 GHz, and the τ f value of −52 ppm/°C were obtained for (Mg 1/2 Zn 1/2 )Al 2 O 4 ceramics sintering at 1600 °C for 4 h (Mg 1/2 Zn 1/2 )Al 2 O 4 is proposed as a suitable material candidate for application in high selective microwave ceramic resonator, filter, and antenna.

An unusual μ1,1,3-cyanamido bridged trinuclear copper complex, [(2,2′-bpy)6Cu3(NCN)](ClO4)4·H2O (1) (2,2′-bpy = 2,2′-bipyridine), has been synthesized and structurally characterized. Magnetic studies show the existence of large antiferromagnetic coupling between the copper(II) ions.