高增强型超声造影特征判断甲状腺可疑恶性结节的单因素及多因素分析

目的应用单因素及多因素分析探讨超声造影(Contrast-enhanced ultrasound,CEUS)高增强型的不同造影特征对甲状腺可疑恶性结节的诊断价值。方法回顾性分析于新疆医科大学第一附属医院行常规超声且CEUS检查呈高增强表现的甲状腺可疑恶性结节患者76例,均行手术并获取病理结果,根据病理结果分为良性组与恶性组。观察常规超声及CEUS特征,并对其进行单因素分析,以有统计学意义的指标为自变量构建二分类Logistics回归模型,评价该模型预测甲状腺结节良恶性的效能。结果良、恶性组间的常规超声及CEUS特征有差异,中央放射状增强、周边不伴高增强环是高增强型甲状腺恶性结节的危险因素,回归模型的ROC曲线下面积为0.854(95%CI:0.761~0.948),该模型诊断甲状腺恶性结节的敏感度、特异度、约登指数分别为86.0%、84.8%、0.708。结论CEUS高增强型的不同造影特征有助于甲状腺可疑恶性结节的鉴别诊断。

肝转移癌超声造影增强模式表现分析

目的研究肝转移癌患者肝内病灶超声造影(CEUS)增强模式。方法2016年1月~2019年1月我院诊治的肝转移癌患者76例,经手术或病灶活检病理学检查诊断,行CEUS和CT增强扫描检查,根据病灶在CT扫描肝动脉期表现为低密度灶者称为乏血供病灶,表现为高密度或等密度灶者为富血供病灶。结果本组肝转移癌的原发灶包括结肠癌50例(65.8%)、乳腺癌7例(9.2%)、肺癌5例(6.6%)、胃癌5例(6.6%)、胰腺癌4例(5.3%)、胰腺神经内分泌肿瘤3例(3.9%)、卵巢癌2例(2.6%);乏血供组肝转移癌来自结肠癌、肺癌、胃癌、胰腺癌和卵巢癌,富血供组肝转移癌来自胰腺神经内分泌肿瘤和乳腺癌;CEUS动脉期成像表现为高增强、局部高增强、同步等增强和不均匀低增强。乏血供组108个病灶动脉期呈高增强、局部高增强、同步等增强和不均匀低增强发生率分别为52.8%、35.2%、3.7%和8.3%,与富血供组24个病灶的87.5%、12.5%、0.0%和0.0%比,差异显著(P<0.05);乏血供组病灶门脉期呈低增强和等增强发生率为分别为99.1%和0.9%,延迟期呈低增强和等增强发生率分别为99.1%和0.9%,与富血供组比,差异显著(分别为70.8%、29.2%、79.2%和20.8%,P<0.05);乏血供组病灶增强时间和病灶达峰时间分别为(17.6±3.8)s和(23.0±4.8)s,显著长于富血供组【分别为(15.2±2.9)s和(19.8±5.9)s,P<0.05],而病灶增强廓清时间为(41.1±23.4)s,显著短于富血供组[(55.8±38.5)s,P<0.05]。结论肝转移癌以乏血供病灶为主,常见的CEUS动脉期增强模式为短暂均匀强化后快速廓清,找到原发病灶有助于对肝内病灶的定性。

常规超声结合超声造影诊断肾占位性病变的价值

目的探讨常规超声结合超声造影对诊断肾占位性病变的临床价值。方法回顾性分析2014年1月至2017年12月东部战区总医院收治的肾占位性病变患者174例的临床资料,所有患者术前均进行常规超声及超声造影检查,术后均行病理检查,其中恶性病变148例,良性病变26例。比较超声造影特征中肾良恶性占位的灌注情况、强化程度以及廓清情况,分析肾良恶性占位性病变的诊断价值。结果良性病变与恶性病变患者之间肿瘤大小、回声比较差异有统计学意义(P<0.01),而性别、年龄、血流、边界比较差异无统计学意义(P>0.05),其中肾血管平滑肌脂肪瘤在良性病变中占比最高[73%(19/26)],其超声造影特征为皮质期等增强;肾透明细胞癌在恶性病变中占比最高[84%(125/148)],其超声造影特征为皮质期高增强、周边环状假包膜及内部回声不均匀;两者在灌注方式及强化程度上差异具有统计学意义(P<0.05)。超声造影诊断肾良恶性占位性病变的特异度为84.6%,灵敏度为97.3%,准确度95.4%。结论超声造影皮质期高增强、周边环状假包膜及内部回声不均匀是诊断肾恶性占位的重要特征,而皮质期等增强是诊断肾良性占位的主要特征。超声造影皮质期对肾占位性病变具有重要的诊断价值。

Mechanical properties of calcium carbonate whisker-reinforced high-strength cement mortar

In order to improve the brittleness of high-strength cement mortar,calcium carbonate（CaCO3） whiskers are incorporated to strengthen and toughen the high-strength cement mortar.The compressive strength,flexural strength,split tensile strength and work of fracture are measured.Microstructures and micromechanical behaviors are investigated using scanning electron microscopy.The strengthening and toughening mechanisms and the efficiency of whisker-reinforced high-strength cement mortar are discussed.The results show that the addition of CaCO3 whiskers brings positive effects on the high-strength cement mortar.The strengthening and toughening mechanisms are whisker-cement coalition debonding,whisker peeling,whisker impact breakage and whisker bridging.Crack deflection is one efficient mechanism,but it is hard to be achieved in high-strength cement mortar.And the interfacial bonding strength between whiskers and the cement mortar matrix should be appropriately weak to introduce more crack deflection mechanisms to strengthen and toughen the cement mortar efficiently.

Experimental and numerical study on flexural behaviors of steel reinforced engineered cementitious composite beams

To investigate the flexural behaviors of steel reinforced engineered cementitious composite （ECC） beams, the behaviors of the steel reinforced ECC beam and the conventional steel reinforced concrete beam subjected to flexural load are experimentally compared. The experimental results show that the flexural strength and ductility of the steel reinforced ECC beam are 24.8% and 187.67% times larger than those of the steel reinforced concrete beam, and the substitution of concrete with ECC can significantly delay the propagation of cracks. Additionally, a simplified constitutive model of the ECC material is used to simulate the flexural behaviors of beams by the finite element analysis （FEA）. The results show a good agreement between the simulation and test results. The crack width of the steel reinforced ECC beam can be limited to 0.4 mm under the service load conditions. The application of ductile ECC can significantly increase the flexural performance in terms of flexural strength, deformation capacity and ductility of the beams.

Microstructures and mechanical properties of extruded 2024 aluminum alloy reinforced by FeNiCrCoAl_3 particles

Different proportions of commercial 2024 aluminum alloy powder and FeNiCrCoA13 high entropy alloy （HEA） powder were ball-milled （BM） for different time. The powder was consolidated by hot extrusion method. The microstructures of the milled powder and bulk alloy were examined by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. Mechanical properties of the extruded alloy were examined by mechanical testing machine. The results show that after BM, the particle size and microstructures of the mixed alloy powder change obviously. After 48 h BM, the average size of mixed powder is about 30 nm, and then after hot extrusion, the average size of grains reaches about 70 rim. The compressive strength of the extruded alloy reaches 710 MPa under certain conditions of milling time and composition. As a result of the identification of the nano-/micro-strueture-property relationship of the samples, such high strength is attributed mainly to the nanocrystalline grains of a（Al） and nanoscaled FeNiCrCoAl3 particles, and the fine secondary phase of Al2Cu and Fe-rich phases.

Edge enhancement of gravity anomalies and gravity gradient tensors using an improved small sub-domain filtering method

In order to enhance geological body boundary visual effects in images and improve interpretation accuracy using gravity and magnetic field data, we propose an improved small sub-domain filtering method to enhance gravity anomalies and gravity gradient tensors. We discuss the effect of Gaussian white noise on the improved small sub-domain filtering method, as well as analyze the effect of window size on geological body edge recognition at different extension directions. Model experiments show that the improved small sub-domain filtering method is less affected by noise, filter window size, and geological body edge direction so it can more accurately depict geological body edges than the conventional small sub-domain filtering method. It also shows that deeply buried body edges can be well delineated through increasing the filter window size. In application, the enhanced gravity anomalies and calculated gravity gradient tensors of the Hulin basin show that the improved small sub-domain filtering can recognize more horizontal fault locations than the conventional method.

Doped-Chamber Deposition of Intrinsic Microcrystalline Silicon Thin Films and Its Application in Solar Cells

A series of microcrystalline silicon thin films were fabricated by very high frequency plasma enhanced chemical vapor deposition （VHF-PECVD） at different silane concentrations in a P chamber. Through analysis of the structural and electrical properties of these materials,we conclude that the photosensitivity slightly decreased then increased as the silane concentration increased,while the crystalline volume fraction indicates the opposite change. Results of XRD indicate that thin films have a （220） preferable orientation under certain conditions. Microcrystalline silicon solar cells with conversion efficiency 4. 7% and micromorph tandem solar cells 8.5% were fabricated by VHF-PECVD （p layer and i layer of microcrystalline silicon solar cells were deposited in P chamber）, respectively.

Fabrication of Hydrogenated Microcrystalline Silicon Thin Films at Low Temperature by VHF-PECVD

Using H 2 diluted silane,series of μc Si∶H films are fabricated at low temperature with VHF PECVD.The thickness measurements reveal that the deposition rates are obviously enhanced with higher plasma excitation frequency or working pressure,but increase firstly and then decrease with the increase of plasma power density.Raman spectra show that the crystallinity and the average grain sizes of the films strongly depend on the temperature of substrate and the concentration of silane.However,the plasma excitation frequency only has effect on the crystallinity,and a maximum occurs during the further increase of plasma excitation frequency.From XRD and TEM experiments,three preferential crystalline orientations (111),(220) and (311) are observed,and the average grain sizes are different for every crystalline orientation.

A High Linearity,13bit Pipelined CMOS ADC

A 13bit,pipelined analog-to-digital converter （ADC） designed to achieve high linearity is described. The high linearity is realized by using the passive capacitor error-averaging technique to calibrate the capacitor mismatch error, a gain-boosting opamp to minimize the finite gain error and gain nonlinearity,a bootstrapping switch to reduce the switch on-resistor nonlinearity, and an anti-disturb design to reduce the noise from the digital supply. This ADC is implemented in 0.18μm CMOS technology and occupies a die area of 3.2mm^2 , including pads. Measured performance includes - 0.18/ 0.15LSB of differential nonlinearity, -0.35/0.5LSB of integral nonlinearity, 75.7dB of signal-to-noise plus distortion ratio （SNDR） and 90. 5 dBc of spurious-free dynamic range （SFDR） for 2.4MHz input at 2.5MS/s. At full speed conversion （5MS/s） and for the same 2.4MHz input, the measured SNDR and SFDR are 73.7dB and 83.9 dBc, respectively. The power dissipation including output pad drivers is 21mW at 2.5MS/s and 34mW at 5MS/s,both at 2.7V supply.

Flexural behaviors of steel reinforced ECC/concrete composite beams

An engineered cementitious composite （ECC） is introduced to partially substitute concrete in the tension zone of a reinforced concrete beam to form an ECC/reinforced concrete （RC） composite beam, which can increase the ductility and crack resisting ability of the beam. Based on the assumption of the plane remaining plane and the simplified constitutive models of materials, the stress and strain distributions along the depth of the composite beam in different loading stages are comprehensively investigated to obtain calculation methods of the load-carrying capacities for different stages. Also, a simplified formula for the ultimate load carrying capacity is proposed according to the Chinese code for the design of concrete structures. The relationship between the moment and curvature for the composite beam is also proposed together with a simplified calculation method for ductility of the ECC/RC composite beam. Finally, the calculation method is demonstrated with the test results of a composite beam. Comparison results show that the calculation results have good consistency with the test results, proving that the proposed calculation methods are reliable with a certain theoretical significance and reference value.

关于做好当前淮河防汛工作的紧急通知

沿淮各市人民政府、各市防汛抗旱指挥部、省政府有关部门:受副高增强西伸,冷暖空气影响,6月29日至30日淮河流域普遍降雨,王家坝以上面雨量达90mm 左右。淮河干流水位上涨,6月30日19时王家坝水位已达26.

Influence of different curing regimes on the microstructure and macro performance of UHPFRCC

This study investigates the influence of different curing regimes on the microstructure and macro properties of ultra-high performance fiber reinforced cementitious composite （UHPFRCC）, and aims to discover whether it is possible to produce qualified UHPFRCC using different curing regimes. A control mix of UHPFRCC is prepared. The mechanical performance and the short-term durability of the UHPFRCC matrix under three curing regimes are studied. In addition, the microstructures of the UHPFRCC matrix with different curing conditions are analyzed by combining scanning electron microscopy （SEM） and mercury intrusion porosimetry （MIP）. The results explore how different UHPFRCC curing regimes affect its microstructure and how the microstructure affects its macro behavior. Heat and steam curing for 3 d is succeeded to produce the UHPFRCC with nearly the same mechanical properties and durability as those of the 90 d standard curing. However, the heat cured UHPFRCC does not show great resistance to chloride-ion penetration.

Monolithic Integration of InGaP/AlGaAs/InGaAs Enhancement/Depletion-Mode PHEMTs

The monolithic integration of enhancement- and depletion-mode （E/D-mode） InGaP/AIGaAs/InGaAs pseudomorphic high electron mobility transistors （PHEMTs） with a 1.0μm gate length is presented. Epilayers are grown on SI GaAs substrates using MBE. For this structure, a mobility of 5410cm^2/（V · s） and a sheet density of 1.34 × 10^12 cm^-2 are achieved at room temperature. During the gate fabrication of E/D-mode PHEMTs,a novel twostep technology is applied. The devices with a gate dimension of 1μm × 100μm exhibit good DC and RF performances. Threshold voltages of 0. 2 and -0. 4V,maximum drain current densities of 300 and 340mA/mm,and extrinsic transconductances of 350 and 300mS/mm for E- and D-mode PHEMTs are obtained, respectively. The reverse gatedrain breakdown voltage is -14V for both E- and D-mode. Current-gain cutoff frequencies of 10. 3 and 12.4GHz and power-gain cutoff frequencies of 12.8 and 14.7GHz for E- and D-mode are reported, respectively.

Challenges of Process Technology in 32nm Technology Node

According to the international technology roadmap for semiconductors （ITRS）,32nm technology node will be introduced around 2009. Scaling of CMOS logic devices from 45 to 32nm node has come across significant barriers. Overcoming these pitch-scaling induced barriers requires integrating the most advanced process technologies into product manufacturing. This paper reviews and discusses new technology applications that could be potentially integrated into 32nm node in the following areas：extension of immersion lithography,mobility enhancement substrate technology,metal/ high-k （MHK） gate stack, ultra-shallow junction （USJ） and other strain enhancement engineering methods, including stress proximity effect （SPT）, dual stress liner （DSL）, stress memorization technique （SMT）, high aspect ratio process （HARP） for STI and PMD,embedded SiGe （for pFET） and SiC （for nFET） source/drain （S/D） using selective epitaxial growth （SEG） method,metallization for middle of line （MOL） and back-end of line （BEOL） ,and ultra low-k （ULK） integration.

A comparison study of atmospheric circulations and potential vorticity anomaly between the two rapid-intensified typhoons

For two rapid-intensification typhoons-Mujigae(2015)and Vicente(2012)-the atmospheric circulation conditions and potential vorticity(PV)anomaly are compared.Although similar in their rapid-intensification(RI)rate,their atmospheric circulation conditions differ considerably,with the absence or presence of an upper-tropospheric inverted trough(IT)being their main difference.The IT provides useful clues for the onset of RI,by estimating the interaction between the environmental upper-tropospheric IT and the typhoon based on eddy momentum flux convergence calculation.The trough–typhoon interaction is examined by comparing the PV transport process for the two cases.An isolated positive PV column develops vertically near Mujigae’s onset of RI,which is not influenced by synoptic-scale PV advection.However,for Vicente,another source-advection from a high-latitude PV reservoir along the upper-tropospheric IT-joins the built-up high-PV anomaly in favor of RI.

Seismic behaviors of steel reinforced ECC/RC composite columns under low-cyclic loading

To improve the seismic performance of columns, engineered cementitious composite （ECC） is introduced to partially substitute concrete at the base of the columns to form ECC,/reinforced concrete （ RC） composite columns. The mechanical behaviors of the ECC/RC composite columns are numerically studied under low-cyclic loading with the finite element analysis softwareof MSC. MARC. It is found that the ECC/RC composite columns can significantly enhance the load capacity, the ductility ad energy dissipation of columns. Then, the effects of the height of the ECC, the axial compression ratio and the longitudinal reinforcement ratio on the seismic behaviors of the composite columns are parametrically studied. The results show that the ECC/RC composite column with a height of the ECC layer of 0. Sh（h is the height to the cross-section） can achieve similar seismic performance of a full ECC column. The peak load of the composite column increases significantly while the ductility decreases with the increase of the axial compression ratio. Increasing the longitudinal reinforcement ratio within a certain range can improve the ductility and energy dissipation capacity and almost has no effect on load capacity. The aalysis results ae instructive and valuable for reference in designing ECC structures.

Flexural behavior of steel reinforced engineered cementitious composite beams

In order to enhance the durability of steel encased concrete beams, a new type of steel reinforced engineered cementitious composite(SRECC) beam composed of steel shapes, steel bars and ECC is proposed. The theoretical analyses of the SRECC beam including crack propagation and stress-strain distributions along the depth of the composite beam in different loading stages are conducted. A theoretical model and simplified design method are proposed to calculate the load carrying capacity. Based on the proposed theoretical model, the relationship between the moment and corresponding curvature is derived. The theoretical results are verified with the finite element analysis. Finally, an extensive parametric study is performed to study the effect of the matrix type, steel shape ratio, reinforced bar ratio, ECC compressive strength and ECC tensile ductility on the mechanical behavior of SRECC beams. The results show that substitution concrete with ECC can effectively improve the bearing capacity and ductility of composite beams. The steel shape and longitudinal reinforcement can enhance the loading carrying capacity, while the ductility decreases with the increase of steel shape ratio. ECC compressive strength has significant effects on both load carrying capacity and ductility, and changing the ultimate strain of ECC results in a very limited variation in the mechanical behavior of SRECC beams.

A 1V,156.7μW,65.9dB Rail-to-Rail Operational Amplifier by Means of Negative Resistance Load and Replica-Amplifier Gain Enhancement

A low-voltage, low-power, and high-gain rail-to-rail operational amplifier （OpAmp） is presented. The replica-amplifier gain enhancement technique is applied to improve the DC gain of the amplifier, which does not degrade the output swing and is very suitable for low-voltage applications. In a 0. 18/μm standard CMOS process,a 1V OpAmp with rail-to-rail output is designed. For a load capacitance of 5 pF,simulation by HSPICE shows that this OpAmp achieves an effective open-loop DC gain of 65. 9dB,gain bandwidth of 70.28 MHz,and phase margin of 50 with a quiescent power dissipation of 156.7μW.

Main properties of ultra-high performance fiber reinforced cement composites under couple effect of load and environment

This study aims to reveal the mechanism that how the content of steel fibers and strength grades affect the macro performance of the ultra-high performance fiber reinforced cementitious composite （UHPFRCC） and to study the UHPFRCC durability under the combined effect of loads and environments. Three types of high and ultra-high performance fiber reinforced cement composites with different strength grades （100, 150, 200 MPa） and different steel fiber volume fractions （0%, 1%, 2%, 3%） are prepared. The main properties of mechanical performance and short-term durability are studied. A preloading frame is designed to apply a four- point load external flexural stress with a stress selection ratio of 0.5 for UHPFRCC150 specimens. The results show that the growth in strength grade with a proper content of steel fiber greatly increases the strength and toughness of the HPFRCC and the UHPFRCC while decreasing the dry-shrinkage ratio. For the loaded specimens, the existence of steel fiber can reduce the negative influence of tensile stress on the Cl- penetration resistance of the UHPFRCC in addition to improving its ability to resist the freeze-thaw damage.