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The Bi(HHTP) nanobelt electrode with charge storage mechanisms for battery-type and surface-capacitive modes displayed a high specific capacitance of 234.0 F g−1.

Piezocatalysis, driven by mechanical energy and piezoelectric effect, is of great potential in addressing the environmental issues. In this work, a piezoelectric catalyst was fabricated by growing few-layer MoS2 nanosheets onto CuS, for the piezocatalytic degradation of Rhodamine B (RhB), methylene blue (MB) and hexavalent chromium (Cr (VI)). The excellent removal efficiency of Cr (VI) and RhB can be reached 100% within 180 s, through the piezocatalysis of CuS/MoS2-0.6 driven by mechanical stirring in the dark. Impressively, the piezoelectric current of CuS/MoS2-0.6 is 48 and 35.7 times higher than that of pure CuS and MoS2, respectively. The significantly enhanced piezocatalytic performance can be ascribed to the formation of CuS/MoS2 heterojunction and the piezoelectric field generated by MoS2 nanosheets, which promotes the efficient separation of electrons and holes. This study provides insights into strategies to improve catalytic performance through utilizing mechanical energy and opens a new horizon for environmental remediation.

Gas barrier property and microstructure of reduced graphene oxide/polyethyleneimine multilayer films createdviarecast and layer-by-layer deposition processes.

Elemental doping is the main means to regulate the phase transition of vanadium oxide (VO2); however, the effects of low valence elemental (

Vacancy defects have important impacts on the physical-chemical properties of metal oxides. In the present work, two types of Bi2O3 powders with different morphologies were synthesized for supercapacitor electrodes by calcination (denoted as c-Bi2O3) and two-step hydrothermal methods (donated as h-Bi2O3). Vacancy clusters of V B i ‴ V O · · V B i ‴ with different concentrations were observed in these two samples by positron annihilation lifetime spectroscopy. The results of electrochemistry revealed that the charge storage behavior of h-Bi2O3 with more V B i ‴ V O · · V B i ‴ defects obeyed both semi-infinite diffusion-controlled battery-type mechanism and surface-controlled pseudo-capacitance mechanism, while that of the calcined c-Bi2O3 electrode with a lower concentration of V B i ‴ V O · · V B i ‴ defects followed only the semi-infinite diffusion-controlled battery-type mechanism. The pseudo-capacitance of h-Bi2O3 could be attributed to the insertion/extraction process of more K+ ions in the V B i ‴ V O · · V B i ‴ surface defects. Due to the partial pseudo-capacitance and improved conductivity caused by more V B i ‴ V O · · V B i ‴ defects, the h-Bi2O3 electrode had a larger capacitance (1043 F g-1 at 1 A g-1), a higher rate performance (560 F g-1 at 60 A g-1), and better cycle stability (93% retention at 50 A g-1 after 2000 cycles). Furthermore, because of the high-concentration of V B i ‴ V O · · V B i ‴ defects, the Ni/Co-MOF//h-Bi2O3 asymmetric supercapacitor delivered a relatively higher specific energy density of 47 Wh kg-1 at 1125 W kg-1. Taken together, these results indicate that surface vacancy clusters play an important role in boosting the electrochemical performance of metal oxide electrodes.

Nafion composite membranes with various amounts of sulfonated multi-walled carbon nanotubes (Su-CNTs) were prepared either in or without a strong magnetic field. Interestingly, it is found that being recast in a strong magnetic field, the tensile strength at break and proton conductivity of Su-CNTs/Nafion composite membranes parallel to the magnetic field direction were higher than those perpendicular to magnetic field. Remarkably, such anisotropic mechanical property and proton conductivity of Su-CNTs/Nafion composite membranes strongly depend on water uptake and temperature, in particular the content of Su-CNTs. Quite a different dependence of the proton conductivity of the composite membranes on Su-CNT content, relative humidities and temperatures is well explained for the anisotropic proton conductivity of the Su-CNTs/Nafion membrane recast in a strong magnetic field, which is attributed to the preferential proton transporting along ionic water channels mainly coalesced by the orientated Su-CNTs at a specific water uptake. For Nafion composite membranes with 5 wt.% Su-CNTs, the proton conductivity along the direction of treating magnetic field approaches to 0.216 S/cm, which is $$\sim$$ 46% higher than that perpendicular to the magnetic field at 95 $$^{\circ }$$ C. The present work provides a deep insight of the humidity and temperature dependence of proton conductivity of Su-CNTs/Nafion composite membranes and a new strategy for fabrication proton exchange membranes with high proton conductivity as well as good mechanical property.

Silicone rubber is widely used in power grids, electronics and aerospace, because of its hydrophobicity, high flexibility, etc. However, it is susceptible to some environmental chemical factors, such as NO2 and ozone, which can induce chain scission, the generation of defects and the ingress of water. In this work, we systematically studied the microstructure variations and water diffusion behavior of high-temperature vulcanized (HTV) silicone rubber after NO2-induced oxidative damage. Microstructure evolution in silicone rubber was investigated by positron annihilation lifetime spectroscopy (PALS). The results show that the oxidation of NO2 significantly degrades organic matrices, which induces the decrease of crosslinking degree and the formation of defects compared to virgin samples. The water transportation was evaluated by electrochemical impedance spectroscopy (EIS), which showed that the diffusion coefficient, under the NO2 concentration of 28.75 mg L−1, is 106 times that of virgin sample with a water uptake of 31%. Particularly, when the concentration reaches the critical value around 17.25 mg L−1, the diffusion coefficient and water uptake increase sharply, and the calculated average porosity of samples also dramatically increases by 4 orders of magnitude. These indicate the formation of more nano- and micron holes, serving as a pointer for percolation of defects in silicone rubber bulk. The study of microstructure variations and water transportation can help us to understand the aging mechanism, design reasonable composite polymer materials and prevent the damage of chemical contact.

Fumed silica (FS)-filled polydimethylsiloxane (PDMS) composite is widely used as the external insulating material in power grid. The function of PDMS composite is to keep the core of an insulation device being dry by preventing the permeation of outside water. To study water diffusion in PDMS composite helps to shed light upon the failure mechanism of the insulation devices. In this paper, positron annihilation lifetime spectroscopy (PALS) and electrochemical impedance spectroscopy (EIS) were applied to study the FS/PDMS interface structure and water diffusion in PDMS composite. It is found that the FS has two basic existing states in PDMS matrix: dispersed state and percolated state, and the percolation threshold of FS is fitted to be 6.0 wt.%. In the dispersed state, the FS particles are randomly dispersed in PDMS matrix. The values of $$\tau _3$$ remain stable, being approximately 1.0 ns, indicating no overlaps of the FS/PDMS interfaces. Moreover, water cannot diffuse through the sample after corona aging. In the percolated state, the FS particles are tightly packed in the PDMS matrix. The values of $$\tau _3$$ decrease with the weight fraction of FS, suggesting the overlapping of the FS/PDMS interfaces. As the FS percolates in sample bulk, these overlapped FS/PDMS interfaces provide continuous diffusion tunnels for water, thus resulting in failure of the composite after corona aging. It is found that polarization and discharge of the electrons at FS/PDMS interface under corona discharge is the main mechanism that leads to the failure of the composite bulk.

A novel method for measuring temperature and conducting tensile tests of metallic wires at elevated temperatures is presented. Ohmic heating is used to elevate the sample temperature with a uniform distribution, which could vary from room temperature to its melting point. The temperatures of the wires in steady states are determined by using a heat transfer model without measuring directly by thermometers, which reduces the error introduced by contact temperature measurement or optical pyrometers. This technique for temperature measurement can be applied to measuring temperature-dependent electrical resistivity and conducting temperature-dependent tensile tests of metallic materials. A low-cost instrument was designed to conduct the tensile tests. In this work, temperature-dependent Young’s modulus, tensile strength at break, and the steady-state creep rate of 99.994%-pure Pb wires were further determined as applications of the tensile tests. The results show that the proposed method is valid and very useful for conducting temperature-dependent tensile tests of metallic materials.

The incorporation of oxygen vacancy defects into the catalysts has been attracting significant interest for regulating the performance of photocatalysts. Single-atomic-site metal catalysts have als...

Nowadays, graphene/polymer composite films with multilayer structure have attracted significant attention for gas barrier application. In this study, a series of reduced graphene oxide/polyethyleneimine (RGO/PEI) composite films were created

Two fluoro-containing low dielectric polymers have been successfully prepared based on thermo-crosslinkable trifluorovinyl ether (TFVE) monomers with big tetrahedral units (adamantane and spirobifluorene). These polymers exhibit an average dielectric constant (Dk) of lower than 2.6, and the polymer with adamantane units displays the lowest Dk of 2.26 and an average dielectric loss (Df) of 1.14 × 10−3 at a range of frequencies from 1 to 10 MHz. In contrast, the polymer with spirobifluorene units displays a Dk of 2.54 and a Df of 1.53 × 10−3. Such results are attributed to the existence of intrinsic micropores produced by the big adamantane and spirobifluorene units in the polymers. Positron annihilation lifetime spectroscopy (PALS) indicates two different micropores in both the polymers, with sizes of 2.354/4.354 and 2.949/4.408 A, respectively. Because the polymer with adamantane units possesses bigger pore sizes, it shows a lower dielectric constant. These data mean that the polymer with adamantane units is suitable for use as encapsulation resins of integrated circuit (IC) dies for applications in the microelectronics industry.

TiO2-Based photocatalysts with hollow structure have attracted much attention owing to their low density, scattering effect and slow photon effect. However, the wide bandgap (Eg = 3.2 eV) and high recombination rate of photogenerated charges hinder their practical application. Herein, a novel hollow urchin-like black RuO2/TiO2/Pt photocatalyst with surface Ti3+ and bulk single-electron oxygen vacancies (Vo·) due to self-doping is reported for visible-light photocatalytic activity. Space-separated dual cocatalysts (RuO2 and Pt NPs) with redox capability can greatly improve the separation efficiency of photogenerated electrons and holes of TiO2. Furthermore, constructing surface Ti3+ and bulk Vo· in TiO2 is considered an efficient approach for narrowing bandgap and enhancing the visible-light absorption. In particular, the surface Ti3+ promotes a self-hydrogenated shell to reduce the activation barrier of H2, which enhances the hydrogen evolution. However, excessive bulk Vo· as carrier recombination centers are not conducive to the hydrogen production. Positron annihilation lifetime spectra (PALS) indicated that the concentration ratio of surface Ti3+ and bulk Vo· is a key factor for efficient photocatalytic hydrogen evolution. The synergy between the spatially separated dual cocatalysts and optimum surface Ti3+/bulk Vo· ratio greatly increases the activity of the catalyst under visible light.

A piezoelectric catalyst of the MoS2@TNr composite (MoS2 nanosheets composited with TiO2 nanorods) was synthesized by a two-step hydrothermal method, and can be recycled and reused as an advanced anode material for supercapacitors. In the dark, the MoS2@TNr composite exhibited ultra-fast piezoelectric catalytic performance and good cycle stability on dye degradation; within 10 min, nearly all rhodamine B (50 mL, 20 ppm) was removed from the solution with the assistance of magnetic stirring. After the 5 cycle degradation reaction, the catalyst was reclaimed and applied to electrochemical testing, which showed better supercapacitor capacitance properties than the fresh catalyst due to the introduction of oxygen vacancies generated from the piezoelectric degradation process. The reclaimed catalyst demonstrated an excellent specific capacitance of 249 F g−1 at 1 A g−1, and 92% capacitance retention after 10 000 cycles. Furthermore, as the current density increased to 30 A g−1, the capacitance could maintain 58% of the initial value. Thus, it can be concluded that the abandoned catalysts may serve as a potential electrode material for energy storage; simultaneously, the reutilization could eliminate secondary pollution and decrease the energy consumption in efficiency.

Defect engineering in photocatalysts represents a fundamental method toward tailoring their solar-to-chemical energy conversion performance, although determining the nature and impact of subsurface...

In this paper, Bi2O3 samples were prepared by a hydrothermal way. The effects of microstructure on the electrochemical properties of Bi2O3 samples were studied by adjusting hydrothermal time of synthesization (2, 6, 10, 14, and 18 h) to control the microstructure. The structure, morphology, specific surface, and chemical environment of Bi2O3 were characterized by XRD, SEM, BET, and XPS. XRD patterns revealed that all diffraction peaks intensity increased with the increase of reaction time and it indicates that a higher crystallization had taken place. However, continuous improvements in electrochemical properties of the samples were not found with enhancement of the crystallinity. The specific capacitance decreases with the increase of crystalline grain size. From the SEM results, as the hydrothermal time increases, it is obvious that the sample particles agglomerate to flakes and then to flowers. The sample of Bi2O3 with a hydrothermal time of 10 h exhibited a high specific capacitance (980 F g−1 at 1 A g−1), excellent capacity retention (86.9% from 1 to 20 A g−1), and a good cycle stability (85.2% at 5 A g−1 after 1000 cycles). The significance of this work is that it is possible to boost the electrochemical properties of the samples by controlling the microstructures, including reducing the crystalline grain size and maintaining a proper morphology of Bi2O3 particles.

Porous carbons have recently drawn extensive attention in energy conversion and storage devices. Boosting energy densities of carbon family is still a challenge due to their limited surface area and accessible active sites. In this work, porous carbons with hierarchically structures were prepared from natural Juncus effuses (CJE) and homogeneous MnO 2 layer was successfully incorporated on their surfaces without changing their original porous structure. The CJE/MnO 2 composite showed large specific capacitance (283 F/g at 1 A/g), which was on account of high specific surface area (1283 m 2 /g) and abundant active sites for pseudocapacitance, particularly, resulted from the introduction of MnO 2. Significantly, the assembled symmetric supercapacitor from CJE/MnO 2 in Na 2 SO 4 aqueous electrolyte delivered high energy/power densities (19.13 Wh/kg at 225 W/kg and 13.73 Wh/kg at 8984 W/kg) and good cyclic performance (86.2% capacitance retention over 5000 cycles at 10.0 A/g). These results demonstrate the CJE/MnO 2 composite can be a potential candidate for supercapacitors.

In this paper, gas chromatography–mass spectrometry (GC–MS) and positron annihilation lifetime spectroscopy (PALS) were used to probe the changes of oligomers and the polydimethylsiloxane (PDMS) network in silicone rubber, after different durations of UVA/UVB irradiation. At the early stage (&lt, 300 h) of UVA/UVB irradiation, the concentration of D4-D9 decreases. The o-Ps intensity of the extracted silicone rubber increases in the stage after UVB irradiation. These results indicate the crosslinking of oligomers into the PDMS network. After a long duration (&gt, 300 h) of UVB irradiation, D4 was generated and the lifetime of τ3 also increased, indicating the rupture of the Si-O bond in the PDMS network. These two aging processes were termed the post curing process and the chain session process. The new finding was that UVA could only induce the post curing process, UVB causes the rupture of the chemical bond in silicone rubber. Photons of UVB could break the C-H bond, and then trigger the backbiting decomposition of PDMS, breaking the Si-O bond, while the photons of UVA cannot. The fact that D4 was generated after UVB irradiation can be used to evaluate the UVB stability of silicone rubber in the future.

Tunable mesoporous silica films were prepared though a sol-gel process directed by the self-assembly of various triblock copolymers. Positron annihilation γ-ray energy spectroscopy and positron annihilation lifetime spectroscopy (PALS) based on intense pulsed slow positron beams as well as ellipsometric porosimetry (EP) combined with heptane adsorption were utilized to characterize the open porosity/interconnectivity and pore size distribution for the prepared films. The consistency between the open porosities was examined by the variations of orthopositronium (o-Ps) 3γ annihilation fractions and the total adsorbed volumes of heptane. The average pore sizes deduced by PALS from the longest-lived o-Ps lifetimes are in good agreement with those by EP on the basis of the Barrett–Joyner–Halenda model, as indicated by a well fitted line of slope k = 1. The results indicate that the EP combined with heptane adsorption is a useful method with high sensitivity for calibrating the mesopore size in highly interconnected mesoporous films, whereas PALS is a novel, complementary tool for characterizing both closed and open pores in them.

In this work, porous KOH-activated biomass carbon (KBC) was obtained from pomelo peel, a simple and effective strategy of one-step incorporating N and B into the porous carbon was introduced. Ammonium borate trihydrate was successfully used to fabricate N, B-codoped KOH-activated biomass carbon (NBKBC) in one-step. NBKBC shows a slight reduction in specific surface area but a distinct higher specific capacitance than KBC. Furthermore, the as prepared NBKBC electrode exhibits an excellent cycling performance. These excellent electrochemical properties of NBKBC were on account of high specific surface area and abundant hierarchically honeycomb-like pores, in particular, N, B codoping. Results shows that it is promising to use such one-step N, B codoping of porous carbons for the synthesis of high performance supercapacitor electrode materials with cheap and easy-available biomass carbons as precursors.

Anatase titanium dioxide (TiO2) nanocrystals with different percentages (up to 95%) of exposed {101} facet and different concentration ratios of bulk single-electron-trapped oxygen vacancies (SETOVs) to surface oxygen vacancies (SOVs) were prepared by alcohol-thermal method with nanotube titanic acid as the precursor in combination with solid-state reduction by NaBH4. The as-prepared TiO2 nanocrystals were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, electron spin resonance spectroscopy, and ultraviolet–visible light spectrometry. The effects of the percentage of crystal facets and the concentration ratio of bulk SETOVs/SOVs on the photocatalytic hydrogen production rate of TiO2 nanocrystals were investigated with positron annihilation lifetime spectroscopy as well as photocurrent test. Findings indicate that the percentage of the exposed {101} facets of the as-prepared TiO2 nanocrystals and their concentration ratios of bulk SETOVs/SOVs can be well tuned by properly adjusting the amount of NaBH4 and the reduction reaction time as well. Increasing percentage of the {101} facet of anatase TiO2 nanocrystals contributes to improving their photocatalytic hydrogen production activity, because the {101} facets of the anatase TiO2 nanocrystals possess enriched electrons and can act as the reduction sites to enhance the reduction reaction of H+ affording H2 in the sacrifice system of splitting water. Both the bulk SETOVs and SOVs contribute to the improvement of the light absorption while SOVs can facilitate the separation of photogenerated charges, thereby adding to the photocatalytic activity. However, the bulk SETOVs and excessive SOVs are also the combination centers of photogenerated charges, which means it is essential to maintain a suitable concentration ratio of the bulk SETOVs/SOVs so as to enhance the light absorption and achieve the best separation efficiency of photogenerated charges and achieve the best photocatalytic activity for hydrogen production. Particularly, when anatase TiO2 nanocrystal with a high percentage (95%) of exposed {101} facet is reduced by NaBH4 at a mass ratio of 2: 1 for 20 min, the resultant reduced H-TiO2 nanocrystal (denoted as H-TiO2-R20(2:1)) provides the highest photocatalytic hydrogen productive rate. Furthermore, the combination of 0.5% Pt/H-TiO2-R20(2:1) with 0.5% Pt/WO3 can split water to simultaneously produce H2 and O2, showing promising potential for splitting water affording hydrogen and oxygen.

Ethyl cellulose can be applied as an erasable barrier coating. The microstructure of this coating is a key factor that influences the anti-corrosion property. To investigate the correlation between the hole structure and the acid treatment time, the microstructure of the ethyl cellulose immersed in acid for different times was evaluated. Scanning electron microscopy (SEM) showed that holes enlarged by around 100 nm in the samples immersed for longer time. Electrochemical impedance spectroscopy (EIS) implied that the film resistance decreased, while the positron annihilation lifetime measurement indicated that the free-volume holes enlarged with the increase in the immersing time. All the results were in agreement with each other. A model has been proposed to explain the film resistance, where the film resistance was inversely proportional to the cross-sectional area of pores for ion permeation. The experimental data confirmed that free-volume holes acted as the tunnels for the ions permeating through the EC film. This could be a potential method to evaluate the tortuosity of holes in membranes by coupling the membrane resistance with free-volume hole size.

Tungsten (W) foils were irradiated with 122 MeV 20Ne ions at the Heavy-ion Research Facility in Lanzhou, on which an energy degrader for tailoring the depth distribution of implanting ions was used. SRIM calculation showed that a quasi-homogeneous distribution of atomic displacement damage to 0.16 dpa within a depth of 50 μm was produced in W. The features of radiation damage were characterized with positron annihilation life spectroscopy (PALS) and transmission electron microscopy (TEM) techniques in this study. Results from PALS study indicated that large vacancy clusters characterized by a long positron lifetime component of ∼510 ps were formed in the irradiated W. These clusters may be the nano-voids (an average diameter of ∼1 nm) exhibited in TEM imaging. Radiation-induced dislocation loops were also observed. Both perfect and Frank loops were manifested under the high resolution TEM observation. The experimental observation of a/2 faulted loops in irradiated W was somewhat surprising and it may shed light on the origin of dislocation formation and their evolution in irradiated bcc metals.

A series of MIL-101-SO3H/Nafion composite membranes was synthesized. They show an improved proton conductivity, due to the abundance of SO3H groups, which fosters proton conduction by binding the water molecules and enabling a larger number of conducting sites. Gas (including water vapor, hydrogen, and oxygen) permeability, crystallinity, and free volumes of the MIL-101-SO3H/Nafion composite membranes were investigated, as well as their correlation. By increasing the MIL-101-SO3H content, the gas permeability of the membranes significantly decreases, since the crystalline region is larger and the water-bearing MIL-101-SO3H particles are efficient barriers for the gas molecules. The gas permeation in the composite membranes is a very complex process and the results indicate no simple linear relation between the gas permeability and the free volume size (VFV), or between the gas permeability and the crystallinity. Moreover, it is very interesting to observe that the influence of VFV on the gas permeability is closely related to the size of the particular gas molecules: the larger the size of the gas molecules, the larger the free volume needed to achieve their rapid diffusion in the membrane. The results suggest the presence of a threshold value for VFV, which depends on the size of the gas molecules: when VFV is lower than this value, the gas molecules cannot easily jump through neighboring free volumes to a neighboring site, and, as a result, the permeability drops quickly.

Free volumes, backbone mobility, crystallinity and proton conductivity of Nafion membranes upon thermal annealing were intensively studied. The development of size and distribution of free volumes in Nafion membranes as a function of environmental humidity was found to be closely associated with the adsorbed water molecules and the Nafion backbone mobility. Results suggested a gradual decrement in Nafion backbone mobility as a function of annealing temperature, due to the thermal induced recrystallization. This was further supported by a linear decrement in the o-Ps intensity as a function of membrane crystallinity, because o-Ps atoms mostly annihilated in the amorphous phase in Nafion. Particularly, a significant increment in crystallinity was found in Nafion membranes annealed at temperatures higher than 140 °C. The present results showed that annealing at ∼ 140 °C of Nafion membranes is favourable for their proton conductivity because of the low crystallinity.

To investigate the effectiveness of arthroscopic all-inside combined with outside-in "suture loop" repair for meniscus bucket-handle tear (BHT).Between August 2016 and May 2019, 44 case of meniscus BHT were treated with arthroscopic all-inside combined outside-in "suture loop". There were 29 males and 15 females with an average age of 26.6 years (range, 18-42 years). The causes of injury included sports injury in 31 cases, falling injury in 7 cases, and sprain in 6 cases. There were 32 cases of medial meniscus posterior horn tears and 12 cases of lateral meniscus posterior horn tears. The disease duration ranged from 6 weeks to 3 months. Thirty-three cases were complicated with anterior cruciate ligament rupture. All patients had normal lower limb alignment. The preoperative Lysholm score was 42.1±9.1. According to the evaluation criteria of MRI and BarrettAll the 44 patients were followed up 8-36 months with an average of 16.8 months. At last follow-up, according to the evaluation criteria of BarrettArthroscopic all-inside combined with outside-in "suture loop" repair is a reliable and effective method for the meniscus BHT, which can obtain good joint function.观察并探讨关节镜下全内联合外-内“环抱”式缝合法治疗半月板桶柄样撕裂（bucket-handle tear，BHT）的疗效。.2016 年 8 月—2019 年 5 月，采用关节镜下全内联合外-内“环抱”式缝合法治疗 44 例膝关节半月板 BHT 患者，其中男 29 例，女 15 例；年龄 18～42 岁，平均 26.6 岁。致伤原因：运动损伤 31 例，高处坠落伤 7 例，扭伤 6 例。内侧半月板后角损伤 32 例，外侧半月板后角损伤 12 例。病程 6 周～3 个月。合并前交叉韧带断裂 33 例。所有患者下肢力线均正常。患者术前 Lysholm 评分为（42.1±9.1）分。根据术后 MRI 及 Barrett 等的评价标准评估半月板愈合情况，采用 Lysholm 评分评价疗效。.术后 44 例患者均获随访，随访时间 8～36 个月，平均 16.8 个月。末次随访时，根据 Barrett 等的评价标准获临床愈合 39 例、未愈合 5 例，临床愈合率 88.6%；MRI 评估完全愈合 32 例、部分愈合 7 例、未愈合 5 例，总愈合率 88.6%，完全愈合率 72.7%。Lysholm 评分为（87.8±4.8）分，与术前比较差异有统计学意义（关节镜下全内联合外-内“环抱”式缝合法是治疗半月板 BHT 可靠、有效的方法，能获得良好的关节功能。.

The carrier concentration of the indium tin oxide (ITO) thin films can be enhanced by supplying extra conducting electrons with tin dopants. However, defects and impurities, which are rich around grain boundaries, result in strong carrier scattering. In this work, ITO films prepared by magnetron sputtering were subjected to supercritical carbon dioxide (SCCO2) fluid treatment with different concentrations of InCl3 solutions, In3+ ions were introduced in the grain boundaries for the purpose of regulating defects and impurities there. The photoelectric performance of ITO films was improved significantly after the SCCO2 fluid treatments, which was interpreted for the effects of SCCO2 on as-deposited ITO microstructures based on the experimental results of X-ray photoelectron spectroscopy and positron annihilation lifetime spectroscopy. Upon the SCCO2 fluid treatment, the dehydration effect passivated the dangling bonds around the grain boundaries, meanwhile, the indium ions diffused into the grain boundaries, resulting in the formation of ITO-like lattice structure there.

A piezoelectric catalyst of the MoS

Polyamide thin film composite reverse osmosis membranes on porous polysulfone support were prepared using m-phenylenediamine, trimesoyl chloride and dimethyl sulfoxide (DMSO) with various contents as precursors via an interfacial polymerization. The membrane with heterogeneous multilayer structure was depth-profiled by positron annihilation lifetime spectroscopy based on a pulsed slow positron beam and the thickness of the polyamide active layer can be estimated through fitting the results of depth dependence of o-Ps intensity. The free volume characteristics in the polyamide selective layer of the membranes were evaluated and were correlated with the permeation properties. With increasing DMSO content, mean free volume size (VFV) was enlarged, which was responsible for the enhanced water and sodium chloride permeation. However, the salt rejection was significantly decreased with a slight increase in the VFV around a critical value of 88.0 A3, which was the average size of hydrated sodium and chloride ions. It was well interpreted for that the broadened free volume distribution enables an amount of larger free volumes to be involved in the salt permeation, although little change in VFV was found.