Job Mobility,Patent Ownership and Knowledge Diffusion: Evidence on a Sample of Italian Inventors

On the basis of the original data on the curricula vitae of a group of Italian inventors patenting in the pharmaceutical field, this paper distinguishes between inventors' employers and applicants, and provides new information on their professional careers and their patent ownership regimes, that is whether or not intellectual property rights on inventions are retained by their employers. In addition, the paper confirms that inventors' mobility is an important determinant of knowledge impact and, interestingly, shows that ownership, too, is associated with a greater potential for knowledge diffusion.     

液体颗粒计数器分辨力检定方法研究

为制定得到符合我国仪器现状、满足对不同测量原理(光阻法和电阻法)、不同测量介质(水和油)、不同测量方式(固定粒径档、可调粒径档和不设粒径档)液体颗粒计数器的分辨力检定需求,对现有的几种分辨力检定、校准方法的优缺点进行分析和比较,最终制定得到具有可靠理论基础和可操作性强的分辨力检定方法,并对该方法进行实验验证。结果表明:该检定方法准确可靠,具有很好的可操作性和适用性。     

Electrostatic Evaluation of a Unipolar Diffusion and Field Charger of Aerosol Particles by a Corona Discharge

This article presents a unipolar diffusion and field charger by corona discharge is presented and electrostatically evaluated for charging aerosol particles. The electrostatic characteristics of the charger were investigated with an electrometer by measuring the ion number concentrations corresponding to the discharge and charging currents. The discharge and charging currents, and ion number concentration in the discharge and charging zones of the charger, increased with corona voltage. The magnitudes of the ion number concentration for positive and negative coronas in the discharge zone ranged from 1.34 × 10¹³ to 1.84 × 10¹⁵ ions/m³ and 7.34 × 10¹³ to 2.64 × 10¹⁵ ions/m³, respectively. For the charging zone, the ion number concentrations for positive and negative coronas ranged from 2.95 × 10¹³ to 1.52 × 10¹⁴ ions/m³ and 2.06 × 10¹³ to 1.47 × 10¹⁴ ions/m³, respectively. To predict the behavior of the electric field strength and lines in the discharge and charging zones of the charger, the electric field strength and distribution of the charger in the discharge and charging zones were calculated by a commercial computational fluid dynamics software package. Numerical calculation results of electric field distribution and lines through the inner electrode showed good agreement with experimental results. Also, the mean charge per particle for particle diameters were in the range of 0.01 to 50 µm for various operating conditions of the charger was theoretically evaluated. For both diffusion and field charging, lower aerosol flow rate and higher corona voltage resulted in an increase in the mean charge per particle within the charger. This simple charger proved to be particularly useful in diffusion and field charging of aerosol particles in particulate matter detector instruments for measuring PM10 and PM2.5 concentration.     

阵列式碳纳米管对聚苯胺导电性能影响

用原位聚合法制备了聚苯胺／碳纳米管复合材料,研究了碳纳米管加入时间、搅拌速度等工艺因素对复合材料导电性能的影响。用四极电子电位差计和HT600透射电子显微镜对该复合材料的导电性能和微观形态作了检测。试验结果表明：在原位复合条件下,聚苯胺可以完全包覆在碳纳米管上,而且碳纳米管在聚苯胺基体中呈网状分布,使复合材料的导电性能得到改善。     

传输线路对变送器仪表校准的影响

变送器仪表主要由变送器、传输线路及显示仪表三部分组成,根据输出信号的不同,主要分为直流电流信号变送器和直流电压信号变送器。变送器和显示仪表一般相距几十到几百米甚至更远,两者需要通过传输线路建立联系。在对变送器仪表校准时,不仅要对变送器和显示仪表进行校准,同时要根据信号的传输特点,分析传输线路对不同信号传输的影响。     

延时分辨率对超声相控阵检测性能的影响

超声相控阵检测技术是近年发展起来的一种先进的无损探伤方法,阵元间的延时分辨率是决定超声相控阵检测系统性能的关键因素,通过研究延时分辨率对相控阵检测效果的影响,可以得到延时分辨率和相关性能参数之间的对应关系,从而提高超声相控阵系统的检测性能。     

Measurement of 100 nm and 60 nm Particle Standards by Differential Mobility Analysis

The peak particle size and expanded uncertainties (95 % confidence interval) for two new particle calibration standards are measured as 101.8 nm ± 1.1 nm and 60.39 nm ± 0.63 nm. The particle samples are polystyrene spheres suspended in filtered, deionized water at a mass fraction of about 0.5 %. The size distribution measurements of aerosolized particles are made using a differential mobility analyzer (DMA) system calibrated using SRM^® 1963 (100.7 nm polystyrene spheres). An electrospray aerosol generator was used for generating the 60 nm aerosol to almost eliminate the generation of multiply charged dimers and trimers and to minimize the effect of non-volatile contaminants increasing the particle size. The testing for the homogeneity of the samples and for the presence of multimers using dynamic light scattering is described. The use of the transfer function integral in the calibration of the DMA is shown to reduce the uncertainty in the measurement of the peak particle size compared to the approach based on the peak in the concentration vs. voltage distribution. A modified aerosol/sheath inlet, recirculating sheath flow, a high ratio of sheath flow to the aerosol flow, and accurate pressure, temperature, and voltage measurements have increased the resolution and accuracy of the measurements. A significant consideration in the uncertainty analysis was the correlation between the slip correction of the calibration particle and the measured particle. Including the correlation reduced the expanded uncertainty from approximately 1.8 % of the particle size to about 1.0 %. The effect of non-volatile contaminants in the polystyrene suspensions on the peak particle size and the uncertainty in the size is determined. The full size distributions for both the 60 nm and 100 nm spheres are tabulated and selected mean sizes including the number mean diameter and the dynamic light scattering mean diameter are computed. The use of these particles for calibrating DMAs and for making deposition standards to be used with surface scanning inspection systems is discussed.     

简支板导纳特性研究

通过建立简支板结构导纳分析模型,并通过计算机仿真手段,研究了简支板的内阻尼对结构输入导纳及传递导纳的影响.研究结果表明:在复杂系统结构传统研究中,通常默认成立的前提假设"结构的传递导纳远小于结构的输入导纳"并非无条件的成立,而只有在板内阻尼达到一定值时,该假设才成立,当板内阻尼很小或为零时,传递导纳的影响不可忽略.     

Slip Correction Measurements of Certified PSL Nanoparticles Using a Nanometer Differential Mobility Analyzer (Nano-DMA) for Knudsen Number From 0.5 to 83

The slip correction factor has been investigated at reduced pressures and high Knudsen number using polystyrene latex (PSL) particles. Nano-differential mobility analyzers (NDMA) were used in determining the slip correction factor by measuring the electrical mobility of 100.7 nm, 269 nm, and 19.90 nm particles as a function of pressure. The aerosol was generated via electrospray to avoid multiplets for the 19.90 nm particles and to reduce the contaminant residue on the particle surface. System pressure was varied down to 8.27 kPa, enabling slip correction measurements for Knudsen numbers as large as 83. A condensation particle counter was modified for low pressure application. The slip correction factor obtained for the three particle sizes is fitted well by the equation: C = 1 + Kn (α + β exp(−γ/Kn)), with α = 1.165, β = 0.483, and γ = 0.997. The first quantitative uncertainty analysis for slip correction measurements was carried out. The expanded relative uncertainty (95 % confidence interval) in measuring slip correction factor was about 2 % for the 100.7 nm SRM particles, about 3 % for the 19.90 nm PSL particles, and about 2.5 % for the 269 nm SRM particles. The major sources of uncertainty are the diameter of particles, the geometric constant associated with NDMA, and the voltage.     

起重机变频器对机上其它电气设备的影响

探讨了变频调速在起重机各机构应用的特点，分析了变频器的机理及其对机上其它电气设备不同的影响程度，提出一些对策，以提高起重机电控系统的可靠性。     

取向电工钢中碳化物在冷变形过程中的行为

用场发射扫描电子显微镜观察了取向电工钢在0-68%冷压加工过程中主要组成为碳化物的第二相粒子的分布状态,统计了不同尺寸粒子面密度的变化。结果表明,冷变形过程造成了碳化物粒子的碎化和回溶行为。粒子碎化到一定程度后其回溶可能是热力学自发过程。这种碎化和回溶有利于促进二次再结晶过程的顺利进行和锋锐Goss织构的生成,也有利于促进一次冷轧板的脱碳过程.     

应用电阻率方法研究粉煤灰持碱效应

采用无接触电阻测量方法,通过电阻率随水化时间的关系曲线,研究了粉煤灰水泥中加入NaOH和Na2SO4后净浆水化早期电阻率的变化规律.结果显示,加入粉煤灰后,使早期电阻率明显增加,后期电阻率降低.加入碱后,水化初期电阻率减低,后期电阻率增加.通过不同水化时间电阻率的变化曲线可以研究粉煤灰的持碱效应,并研究碱在粉煤灰水泥中的作用和形成的产物.     

反演解析法提高CCD成像分辨率的噪声影响研究

反演解析法是提高CCD成像分辨率的方法之一。但是，加在低分辨率图像上的随机噪声会对合成的高分辨率图像产生不可预知的影响。中首先介绍了反演解析法原理，然后讨论了噪声的影响机制。并且，为了对噪声影响进行数值化分析，提出了一个噪声影响评价函数。最后，以该函数为基础，通过计算机仿真实验，找到了合成图像受随机高斯白噪声影响的规律。     

The Influence of the Interaction Potential on the Diffusion of Neutral Particles in Oxyfluoride Glasses

A systematic study of the effects of the interaction potential upon the diffusion coefficients of neutral particles (P0s) and ions in the 60GeO₂–40PbF₂ glass has been performed using molecular dynamics simulations. The P0–P0 and P0–ions pair potentials were described by a Lennard–Jones potential with two parameters: the well depth (ε) and the size (σ). These parameters were varied in the ranges: (σ) = 0.1-1.0 eV and σ=1.0−4.0 ?. The diffusion coefficients were calculated for several combinations at several temperatures (300–1200 K). The estimated glass transition temperature (T _g) presented a slight dependence upon the potential parameters, but it is near the crystallization temperature of a glass of similar composition. Whereas, the diffusion coefficients of the P0s presented a strong dependence with the potential parameters, where increasing ε and σ causes a decrease of their diffusion coefficients. These results suggest that the atoms should be responsible for forming any surface film, since neutral particles larger than atom, such as, nanoparticles, should have negligible diffusion.     

电子迁移对钇稳定氧化锆电解质性能的影响

本文讨论了在不同测氧分压、温度、相对密度及引入Al2O3下,电子迁移对钇稳定氧化锆电解质性能的影响。结果表明：氧化锆氧浓差电池测量的氧分压越低,电子迁移对池电势的影响越大;电池的工作温度越低,电子迁移数越大,测量误差越大;烧结越致密的电解质其电子迁移数越小;适量的引入Al2O3可以降低电子迁移数,提高测氧准确性。     

成型烧结过程对钽阳极电性能的影响

以牌号FTA500钽粉为代表,选择容量为50 000 μF·V/g的钽粉,探索了成型过程和烧结过程对钽阳极漏电流、容量等电性能参数的影响。研究表明:随着成型压制密度逐渐增大时,钽阳极块的开孔率减小、容量降低,当成型压制密度为5.00 g/cm³时,阳极块漏电流系数为最低;随着烧结温度的提高,钽阳极烧结密度增大、容量下降、漏电流系数降低,同时钽阳极损耗增大,体积收缩率增大,击穿电压升高。     

L形加筋板结构的导纳功率流研究

Ｌ形加筋板结构的导纳功率流研究李天匀张维衡张小铭（华中理工大学船舶与海洋工程系武汉，４３００７４）摘要针对工程上常用的Ｌ形加筋板结构，利用导纳方法研究了在外载作用下的输入振动功率流和传递振动功率流，考虑了肋骨对板的力和弯矩的影响及粘弹性材料的影响；...     

铜在碳钢中扩散及其对碳钢耐腐蚀性的影响

用水溶液电沉积法在碳钢表面电镀铜并进行高温扩散退火,用Den-Broeder法计算铜在碳钢中的扩散系数,研究了铜在碳钢中的扩散行为及其对碳钢耐腐蚀性的影响。结果表明,铜在碳钢中的扩散主要沿晶界进行,铜的扩散抑制了热处理过程中碳钢晶粒的长大。铜在碳钢中的扩散系数为1.11×10-16～3.03×10-11 cm2/s,扩散系数随着退火温度的提高而升高,随着铜浓度的提高而降低。铜在碳钢高温奥氏体区中扩散所需的激活能为126～167 kJ/mol,在高于低温铁素体+奥氏体混合区中激活能为90～108 kJ/mol。通过铜在碳钢中的扩散制备的Cu-Fe梯度材料,具有优良的耐腐蚀性。     

Design and Evaluation of Four-Stage Low-Pressure Cascade Impactor Using Electrical Measurement System

The low-pressure cascade impactor has been used to collect ultrafine particles that cannot be measured by conventional cascade impactors. Low-pressure cascade impactors resemble ordinary impactors, but are operated at reduced pressures of 0.05 ～ 0.4 atm. Many kinds of low-pressure impactors have been developed by different researchers. However, it is still difficult to accurately design and evaluate the low-pressure cascade impactor.

In this study, a four-stage low-pressure cascade impactor for measuring the size distribution of submicron aerosol particles was designed and evaluated. To evaluate particle collection efficiency of each stage, an electrical measurement system was used. The cut-point diameters of Stages 1 through 4 were 0.238, 0.173, 0.111, and 0.063 μm in aerodynamic diameter. Stage 2 showed poor steepness of the collection efficiency curve and larger cut-point Stokes number than theory, which may be attributed to high nozzle velocity. The fluorometric method for particle collection efficiency measurement was shown to be unreliable for ultrafine particles.

The solid particle collection efficiency of the designed impactor was examined with different substrate conditioning methods. Porous metal substrate and silicon-coated substrate were tested with NaCl particles. It was shown that silicon coating did not effectively reduce the particle bounce because of high nozzle velocity, whereas the porous metal substrate considerably enhanced the particle collection efficiency.