基于FPGA的开关量输入模块设计

在测控系统中,经常需要对各种现场信号进行采集;该模块主要实现对开关量状态信号进行实时监控,记录状态信息,为故障诊断提供依据;在设计中,采用了光耦隔离器件对输入信号进行了隔离和抗干扰处理,使用了FPGA实现了数据实时采集和中断处理,最后经PCI总线与主机进行数据交互;在故障诊断系统中,该信号采集板工作稳定、可靠,能够满足系统的实时性要求。     

Roll‐to‐roll UV embossing process applied for light bar‐based sub‐wavelength gratings for backlight

This study proposes a roll‐to‐roll process‐based sub‐wavelength grating, which is attached on a light bar to turn the side‐lit red/green/blue (620, 520, and 450 nm) incident rays into a uniformly and normally output white light with high illuminance from the light bar's surface. On the basis of the rigorous coupling wave analysis, the relationship between the first‐order transmission/reflection efficiency and the pitch of the gratings with different shapes was analyzed. The optimal design can effectively reduce the coupling length and enhance the white color balance for display applications.     

Decay rate of critical fluctuations in steam and in dilute steam-NaCl mixtures

The decay rate of critical fluctuations in steam and in a steam-NaCl mixture has been investigated experimentally with the aid of photon correlation spectroscopy. For pure steam, the measurements have been performed along seven isochores [(¦– _c¦)/_c<0.09] as a function of the temperatureT for (T–T_t)<1 K. The results have been compared with the values predicted by the renormalization-group theory written as a modification of the classical mode coupling theory. The agreement between experiment and theory is satisfactory along the critical isochore, but larger deviations are noted for _c when approching the transition temperatureT _t. The decay rate of a 0.1% (molar) dilute mixture of NaCl in H₂O has been measured along some near-critical isochores as a function of temperature. Its behavior, which is very different from that observed for pure steam, is dicussed.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

是荧光还是散射光?是生物化学方法还是形态学方法?——与赖省生等同志商榷

本文提出:所谓“荧光扫描法”测定杂交水稻子一代种子纯度的方法,不是测定的荧光,而是测定的散射光,由种子表面对光的散射来进行测定。因而实质上仍然是一种形态学的测定方法。     

Zirconium-based intermetallics as heterogeneous catalysts for the fischer-tropsch reaction: I. Zr-Ni-Co catalysts

Alloys of the general formula Zr₅₀Ni_xCO_50-x, where 0 ≦x≧ 50, have been prepared and used in the temperature range 300–400°C, in the pressure range 1–9 barg in a microtubular reactor for the reaction of hydrogen with carbon monoxide to give hydrocarbons. The alloys or intermetallic materials were prepared by argon arc melting, powdered by hydrogen decrepitation and characterised by means of optical microscopy (metallography), scanning electron microscopy with surface analysis and magnetic susceptibility measurements. The selectivity towards higher hydrocarbons increased with (i) increase in the total pressure and (ii) decrease in hydrogen content of the feed gases. The kinetics were found to be of the form: where m = 1.0 ± 0.2 and n = 0. The apparent energy of activation (E_a) lay in the range of 80–130 kJ mole^?1 and there appeared to be a compensation effect between E_a and the pre-exponential factor A. The turnover numbers for the reaction exhibited an activity maximum for alloys of composition around Zr₅₀Ni₄₀Co₂₀ and Zr₅₀Ni₃₀Co₂₀. Magnetic susceptibility measurements indicated that alloys changed their nature from moderately paramagnetic to strongly paramagnetic or even ferromagnetic after use and this is attributed to the conversion of zirconium to zirconium oxide during reaction with the attendant production of free 3d-transition metals. Derived catalysts prepared by air treatment of the hydrogen-decrepitated intermetallics behaved almost identically to the latter materials and gave similar magnetic susceptibility values to used hydrided materials.     

Thermal diffusivity of fluids in a broad region around the critical point

Dynamic light scattering is a suitable method for the investigation of transport properties such as the thermal diffusivity of optically transparent fluids. The main advantages of the method are its quickness, the fact of the thermodynamic state of equilibrium of the sample (gradients are not required), and the relatively simple evaluation of data without the necessity of calibration. However, an insufficient production of intensity of scattered light may be a limiting effect. For that reason the vicinity of the gas-liquid critical point represents the classical range of application. In this paper, it is shown that by means of an appropriate choice of experimental apparatus, measurements are also feasible in an extended range of states. Broad regions around critical points of three pure fluids (sulfur hexafluoride, SF₆; ethane, C₂H₆; nitrous oxide, N₂O) over temperature ranges ¦T-T _c¦ of 0.02 to 50 K and density ranges (/_c) of 0.2 to 2 were investigated. In this region the thermal diffusivity shows great variations with temperature and density and cannot be described by means of ideal-gas behavior or relations for liquids. The measurements were carried out along the coexistence curve for both phases, along the critical isochore and along some isotherms with TT _c. The measured or calculated density, pressure, and thermal diffusivity data as well as some correlations are presented.     

Differential Action of Connexin Hemichannel and Pannexin Channel Therapeutics for Potential Treatment of Retinal Diseases

Dysregulation of retinal function in the early stages of light-induced retinal degeneration involves pannexins and connexins. These two types of proteins may contribute to channels that release ATP, leading to activation of the inflammasome pathway, spread of inflammation and retinal dysfunction. However, the effect of pannexin channel block alone or block of both pannexin channels and connexin hemichannels in parallel on retinal activity in vivo is unknown. In this study, the pannexin channel blocker probenecid and the connexin hemichannel blocker tonabersat were used in the light-damaged rat retina. Retinal function was evaluated using electroretinography (ERG), retinal structure was analyzed using optical coherence tomography (OCT) imaging and the tissue response to light-induced injury was assessed immunohistochemically with antibodies against glial fibrillary acidic protein (GFAP), Ionized calcium binding adaptor molecule 1 (Iba-1) and Connexin43 (Cx43). Probenecid did not further enhance the therapeutic effect of connexin hemichannel block in this model, but on its own improved activity of certain inner retina neurons. The therapeutic benefit of blocking connexin hemichannels was further evaluated by comparing these data against results from our previously published studies that also used the light-damaged rat retina model. The analysis showed that treatment with tonabersat alone was better than probenecid alone at restoring retinal function in the light-damaged retina model. The results assist in the interpretation of the differential action of connexin hemichannel and pannexin channel therapeutics for potential treatment of retinal diseases.     

一种联合采样的神经网络光场

相比传统的光场绘制技术,神经网络光场(NeRF)方法可使用神经网络拟合场景的光线采样,将隐式编码输入图片的光场,合成新视图. 针对NeRF方法训练时间长,绘制视图慢的问题,提出了一种基于联合采样的NeRF方法,通过使粗糙网络和细腻网络共享均匀采样结果的方法,减少了不必要的光线采样,从而加快了网络训练和视图合成的速度. 实验结果表明,在取得近似视图合成质量的情况下,与NeRF方法相比,所提方法的训练时间减少了20%,视图合成的效率提高了25%.     

Photocatalytic syngas synthesis from CO2 and H2O using ultrafine CeO2-decorated layered double hydroxide nanosheets under visible-light up to 600 nm

The rational design of photocatalyst that can effectively reduce CO₂ under visible light(l>400 nm),and simultaneously precise control of the products syngas(CO/H2)ratio is highly desirable for the Fischer-Tropsch reaction.In this work,we synthesized a series of CeO₂-decorated layered double hydroxides(LDHs,Ce-x)samples for photocatalytic CO₂ reduction.It was found that the selectivity and productivity of CO and H₂ from photoreduction of CO₂ in conjunction with Ru-complex as photosensitizer performed an obvious“volcano-like”trend,with the highest point at Ce-0.15 and the CO/H₂ ratio can be widely tunable from 1/7.7 to 1/1.3.Furthermore,compared with LDH,Ce-0.15 also drove photocatalytic CO₂ to syngas under 600 nm irradiation.It implied that an optimum amount of CeO₂ modifying LDH promoted the photoreduction of CO₂ to syngas.This report gives the way to fully utilize the rare earth elements and provides a promising route to enhance the photo-response ability and charge injection efficiency of LDH-based photocatalysts in the synthesis of syngas with a tunable ratio under visible light irradiation.