腔内泌尿外科技术新进展——双极(等离子体)汽化治疗前列腺增生症

1历史回顾 1925年美国亚美(ACMI)公司发明了第一台用于经尿道切除前列腺(TURP)的器械,由于当时的制造工艺落后,加上一定的操作难度,在TURP问世近20年时间内,该技术只在美国及欧洲几家大型医院内开展.二战结束后,德国、美国及日本将原高科技军工企业(尤其是光学仪器及新材料开发等)转而投向医疗市场,使得内窥镜硬件制造工艺有了质的飞跃.同时,灌洗液也由低渗液改为等渗液,使TURP综合症由原来的30%降至7%以下.因此在20世纪50年代初TURP技术在发达国家及部分发展中国家迅速推广,TURP也即成为一专业术语,并很快被欧美国家正式认定为治疗前列腺增生症的会标准.

Wear and corrosion behavior of clay containing coating on AM 50 magnesium alloy produced by aluminate-based plasma electrolytic oxidation

This study aims to examine the effect of clay micro particles addition on the microstructure,wear and corrosion behavior of PEO coatings on AM 50 magnesium alloy.PEO coatings were prepared using an aluminate-based electrolyte with and without the presence of 5 g/L clay particles.The structure and composition of the coatings were evaluated using SEM,EDS and XRD.The wear investigations were conducted using a ball-on-disk tribometer at 2,5 and 10 N loads.The corrosion behavior of the coatings was examined using polarization and EIS tests in 0.5 wt.%NaCl.The results revealed that the addition of clay particles deteriorated the wear resistance of the coatings under the loads of 5 and 10 N.The SEM examinations of the worn surfaces indicated that a combination of adhesive and abrasive wear mechanisms was activated for the coating with clay particles.The poor wear performance of the clay-incorporated coating was related to its lower adhesion strength and higher roughness.The potentiodynamic polarization examinations revealed that the addition of clay particles slightly decreased the corrosion rate of the coatings.Corrosion resistance of the clay-containing coating was attributed to its compactness,as indicated by the results of EIS tests.

Separation and Manipulation of Rare-earth Oxide Particles by Dielectrophoresis

A challenge in chemical engineering is the separation and purification of rare-earth elements and their compounds. We report the design and manufacture of a dielectrophoresis(DEP) microchip of microelectrode arrays. This microchip device is constructed in order to use DEP to capture micro-particles of rare-earth oxides in petro-leum. Dielectrophoretic behavior of micro-particles of rare-earth oxides in oil media is explored. The dielectropho-retic effects of particles under different conditions are investigated. It is showed that the prepared microchip is suit-able for use in the investigation of dielectrophoretic responses of the rare-earth oxides in oil media. The factors such as frequency,particle size and valence of rare-earth metal are discussed. When the frequency is fixed,the transla-tion voltage decreases as particle size increases. Lower frequencies are more effective for manipulation of inorganic particles in oil media. Particles of the same rare-earth oxide with different size,as well as particles of different rare-earth oxides,are captured in different regions of the field by regulating DEP conditions. This may be a new method for separation and purification of particles of different rare-earth oxides,as well as classification of particles with different size.

Determination of brominated diphenyl ethers in atmospheric particulate matter using selective pressurized liquid extraction and gas chromatography–mass spectrometry with a negative chemical ionization

This study describes the development and validation of a sensitive and reliable method for determination of polybrominated diphenyl ethers（PBDEs）in atmospheric particulate matter using selective pressurized liquid extraction（SPLE）and gas chromatography–mass spectrometry with a negative chemical ionization（GC-NCI-MS）.Extraction and clean-up were performed using PLE with 2 g florisil and 3 g silica placed in the extraction cells.Under optimal conditions,14 PBDEs were extracted at 70℃ using hexane/dichloromethane（50：50,v/v）as solvent.Validation of SPLE returned excellent recoveries for most analytes,with relative standard deviations mostly below20%.Method detection limits ranged from 0.13 to15.38 ng·mL^-1 for the GC-MS analyses.The method was successfully applied to atmospheric particulate matter of Beijing,where analytes were detected in the range of182.79 to 468.99 pg·m^-3.

Effect of the Ni size on CH4/CO2 reforming over Ni/MgO catalyst：A DFT study

Carbon deposition is sensitive to the metal particle sizes of supported Ni catalysts in CH_4/CO_2 reforming.To explore the reason of this phenomenon,Ni4,Ni8,and Ni12 which re flect the different cluster thicknesses supported on the MgO(100) slabs,have been employed to simulate Ni/MgO catalysts,and the reaction pathways of CH_4/CO_2 reforming on Nix/MgO(100) models are investigated by density functional theory.The reforming mechanisms of CH_4/CO_2 on different Nix/MgO(100) indicate the energy barriers of CH_4 dissociated adsorption,CH dissociation,and C oxidation three factors are all declining with the decrease of the Ni cluster sizes.The Hirshfeld charges analyses of three steps as described above show only Ni atoms in bottom two layers can obtain electrons from the MgO supporters,and the main electron transfer occurs between adsorbed species and their directly contacted Ni atoms.Due to more electron-rich Ni atoms in contact with the MgO supporters,the Ni/MgO catalysts with small Ni particles have a strong metal particle size effect and lead to its better catalytic activity.

Nano-Li3V2（PO4）3/C Synthesized by Thermal Polymerization Method as Cathode Material for Lithium Ion Batteries

A nano-Li3V2（PO4）3/C powder was successfully prepared by a thermal polymerization method. The particle sizes of the intermediate product powder and the final product Li3V2（PO4）3 are all less than 200 nm. The carbon is partially coated on the surface of Li3V2（PO4）3 particles and the rest exists between particles with a total carbon content of 4.6wt%. This nano-Li3V2（PO4）3/C sample shows a discharge capacity of 124 mAh/g with-out capacity fading after 100 cycles at 0.1 C in the voltage rang of 3.0-4.3 V. Excellent rate performance is also achieved with a capacity of 80 mAh/g at 20 C in 3.0-4.3 V and 100 mAh/g at 10 C in 3.0-4.8 V. This study suggests that the thermal polymerization method is suitable to synthesize nano-Li3V2（PO4）3/C materials.

Cu nanoparticles supported on graphitic carbon nitride as an efficient electrocatalyst for oxygen reduction reaction

High active and cost‐effective electrocatalysts for the oxygen reduction reaction(ORR)are essential components of renewable energy technologies,such as fuel cells and metal/air batteries.Herein,we propose that ORR active Cu/graphitic carbon nitride(Cu/g‐CN)electrocatalyst can be prepared via a facile hydrothermal reaction in the present of the ionic liquid(IL)bis(1‐hexadecyl‐3‐methylimidazolium)tetrachlorocuprate[(C16mim)2CuCl4]and protonated g‐CN.The as‐prepared Cu/g‐CN showed an impressive ORR catalytic activity that a99mV positive shift of the onset potential and2times kinetic current density can be clearly observed,comparing with the pure g‐CN.In addition,the Cu/g‐CN revealed better stability and methanol tolerance than commercial Pt/C(HiSPECTM3000,20%).Therefore,the proposed Cu/g‐CN,as the inexpensive and efficient ORR electrocatalyst,would be a potential candidate for application in fuel cells.

Synthesis of Sub-micrometer Lithium Iron Phosphate Particles for Lithium Ion Battery by Using Supercritical Hydrothermal Method

A supercritical hydrothermal method was employed to prepare sub-micrometer LiFePO4particles with high purity and crystallinity.The structure and morphology of LiFePO4particles were characterized by X-ray diffraction and scanning electron microscope.The electrochemical tests were carried out to determine the reversible capacity,rate and cycling performance of the LiFePO4particles as cathode material for lithium ion battery.Experimental results show that solvent and calcining time have significant effects on purity,size and morphology of LiFePO4particles.Mixed solvent contained deionized water and ethanol is conducive to synthesize smaller and more uniform particles.The size of LiFePO4particles as-prepared is about 100-300 nm.The specific discharge capacities of the LiFePO4particles are 151.3 and 128.0 mA·h·g?1 after first cycle at the rates of 0.1 and 1.0 C,respectively.It retains 95.0%of the initial capacity after 100 cycles at 1.0 C.

Preparation of carbon-coated iron oxide nanoparticles dispersed on graphene sheets and applications as advanced anode materials for lithium-ion batteries

We report a novel chemical vapor deposition （CVD） based strategy to synthesize carbon-coated Fe203 nanoparticles dispersed on graphene sheets （Fe2Og@C@G）. Graphene sheets with high surface area and aspect ratio are chosen as space restrictor to prevent the sintering and aggregation of nanoparticles during high temperature treatments （800 ℃）. In the resulting nanocomposite, each individual Fe2O3 nanoparticle （5 to 20 nm in diameter） is uniformly coated with a continuous and thin （two to five layers） graphitic carbon shell. Further, the core-shell nanoparticles are evenly distributed on graphene sheets. When used as anode materials for lithium ion batteries, the conductive-additive-free Fe2OB@C@G electrode shows outstanding Li＋ storage properties with large reversible specific capacity （864 mAh/g after 100 cycles）, excellent cyclic stability （120% retention after 100 cycles at 100 mA/g）, high Coulombic efficiency （-99%）, and good rate capability.

Construct Fe^(2+) species and Au particles for significantly enhanced photoelectrochemical performance of α-Fe_2O_3 by ion implantation

Photoelectrochemical（PEC） water splitting is a promising approach to producing H2 and O2. Hematite（α-Fe2O3） is considered one of the most promising photoelectrodes for PEC water splitting, due to its good photochemical stability, non-toxicity, abundance in earth, and suitable bandgap（Eg2.1 eV）. However, the PEC water splitting efficiency of hematite is severely hampered by its short hole diffusion length（2–4 nm）, poor conductivity, and ultrafast recombination of photogenerated carriers（about 10 ps）. Here,we show a novel and effective method for significantly improving the PEC water splitting performance of hematite by Au ion implantation and the following high-temperature annealing process. Based on a series of characterizations and analyses, we have found Fe2＋ species and tightly attached Au particles were produced at Au-implanted hematite. As a result,the charge separation and charge injection efficiency of Auimplanted Fe2O3 are markedly increased. The photocurrent density of optimized Au-implanted Fe2O3 could reach1.16 m A cm-2 at 1.5 V vs. RHE which was nearly 300 times higher than that of the pristine Fe2O3（4 μA cm-2）. Furthermore, the Au-implanted Fe2O3 photoelectrode exhibited great stability for the 8-hour PEC water splitting test without photocurrent decay.

Synthesis and characterization of oriented linked LiFePO4 nanoparticles with fast electron and ion transport for high-power lithium-ion batteries

LiFePO4 nanoparticles with different morphologies and sizes were synthesized via a solvothermal method using environmentally benign and low-cost glycerol as the surfactant. The morphology, size, and structure of the particles were found to relate closely to the concentration of glycerol. Oriented linked LiFePO4 nanorods along mostly non-[010] were obtained with the proper concentration of glycerol. The nanorods showed good electronic and ionic conductivities, resulting in superior rate capability and cycling performance. This performance was attributed to the oriented linkages along mostly non-[010], the small particle size along [010], and the occupation of Li at Fe sites. Initial discharge capacities of 162.4 mA.h.g-1 at 0.1 C and 102.1 mA.h.g-1 at 30 C were achieved, with capacity retentions after 500 cycles at 5 and 20 C of 99.5% and 93.2%, respectively. At the rate of 40 C, the solid-solution phase transition dominated during lithiation and delithiation of all samples.

Controlled Ag-driven superior rate-capability of Li4Ti5O12 anodes for lithium rechargeable batteries

The morphology and electronic structure of a Li4Ti5012 anode are known to determine its electrical and electrochemical properties in lithium rechargeable batteries. Ag-Li4Ti5012 nanofibers have been rationally designed and synthesized by an electrospinning technique to meet the requirements of one-dimensional （1D） morphology and superior electrical conductivity. Herein, we have found that the 1D Ag-Li4Ti5012 nanofibers show enhanced specific capacity, rate capability, and cycling stability compared to bare Li4Ti5012 nanofibers, due to the Ag nanoparticles （〈5 nm）, which are mainly distributed at interfaces between Li4Ti5O12 primary particles. This structural morphology gives rise to 20% higher rate capability than bare Li4Ti5O12 nanofibers by facilitating the charge transfer kinetics. Our findings provide an effective way to improve the electrochemical performance of Li4Ti5O12 anodes for lithium rechargeable batteries.

DC dielectrophoresis separation of marine algae and particles in a microfluidic chip

This paper reports a microfluidic method of continuous separation of marine algae and particles by DC dielectrophoresis. The locally non-uniform electric field is generated by an insulating PDMS triangle hurdle fabricated within a PDMS microchannel. Both the particles and algae are subject to negative DEP forces at the hurdle where the gradient of local electric-field strength is the strongest. The DEP force acting on the particle or the algae depends on particles' or algae's volume, shape and dielectric properties. Thus the moving particles and algae will be repelled to different streamlines when passing the hurdle. In this way, combined with the electroosmotic flow, continuous separation of algae of two different sizes, and continuous separation of polystyrene particles and algae with similar volume but different shape were achieved. This first demonstration of DC DEP separation of polystyrene particles and algae with similar sizes illustrates the great influence of dielectric properties on particle separation and potentials for sample pretreatment.