Multiplane displays based on liquid crystals for AR applications

Multiplane displays are capable of displaying 3D scenes with correct focus cues by creating multilayer 2D images in the display volume. Hence, such a 3D display technique could effectively address the accommodation‐vergence conflict (AVC) problem, which is prevalent in augmented reality (AR) displays. In this paper, we review the recent progress on multiplane AR displays based on liquid crystals (LCs) for AR applications. The working principle of multiplane AR displays is illustrated, the electro‐optical properties of the tunable LC devices are investigated and display prototypes are demonstrated. Finally, we discuss the prospects and challenges of multiplane AR displays based on LCs.     

石灰石矿山台阶边坡爆破振速安全阈值研究

爆破是矿山露采的必要手段,爆破振速安全阈值的确定对矿山台阶边坡的安全开采起着重要的作用。以四川兴联石灰石矿山台阶边坡为例,采用速度判别法,选取规范中的爆破振速安全阈值为拟静力法和动力显示分析法作参考;采用拟静力法,选取优势结构面作为潜在滑动面反演得到爆破振速安全阈值;采用ANSYS/LS-DYNA的动力显示分析法,建立台阶边坡模型,选取模拟监测点数据与实际监测数据进行对比,并结合质点振动速度与应力进行回归分析得到爆破振速安全阈值。通过对三种方法的对比研究得到,拟静力法与动力显示分析法得到的结果接近,且符合速度判别法中的规范。综合三种分析方法最终对台阶边坡爆破振速安全阈值进行合理取值。     

实物地质资料展览展示研究——以国土资源实物地质资料中心为例

为了让国家馆藏实物地质资料资源“看得见、可获取、用得起、盘得活”,服务于拥有不同需求的专业人员和社会公众用户群体,在展览展示内容、展示方法和结构上有所创新,经过深入、系统地科学研究,理清了实物地质资料展览展示的特色,准确把握和定位了展览大纲,使实物展品、辅助展品、展示方式与展厅所在建筑物融为一体,全面科学地落实和确定了实物地质资料展品和布展方案,创新了实物地质资料展览展示技术方法,提出了以国家馆藏实物地质资料为基础的典型实物展示与多媒体全面展示相结合、模块化展览设计的技术思路,为实物地质资料展览展示的进一步研究提供了技术储备。     

Spectral influence of the normal LCD,blue-shifted LCD,and OLED smartphone displays on visual fatigue: A comparative study

In this study, we investigated the influence of the light spectra of the normal LCD, blue-shifted LCD, and OLED smartphone displays on visual fatigue based on subjective and objective measurements. The illuminance of the retinal photoreceptors was calculated for the three displays to quantify the components of the light spectra. The results showed that the accumulated visual fatigue decreased for the display with lower retinal illuminances of the S-, M-, and L-cones, and ipRGCs when the luminance and CCT were the same. In addition, the display with larger retinal illuminances of the M- and L-cones induced more visual fatigue related to dry eye. Hence, a slight shift of the blue light peak toward a longer wavelength is recommended for reducing visual fatigue. Furthermore, an evaluation model of the overall visual fatigue level is proposed.     

Fun and fear: The banalization of nuclear technologies through display

How do nuclear technologies become commonplace? How have the borders between the exceptional and the banal been drawn and redrawn over the last 70 years in order to make nuclear energy part of everyday life? This special issue analyzes the role of fun and display, broadly construed, in shaping the cultural representation and the material circulation (or non‐circulation) of nuclear technologies. Four case studies, covering the United States, Great Britain, Portugal, Spain, and Ukraine from the 1950s to the 2000s, explore how specific forms of public display and playful practices of cultural production were used as means to banalize (or de‐banalize) nuclear energy. This introduction addresses the main theoretical and historiographical signposts of the special issue and outlines the different ways in which the articles explore them.     

恒湿文物展柜用吸附式空气取水方法

博物馆恒湿文物展柜的湿度控制至关重要，为实现展柜的自动恒湿功能，本文基于吸附式空气取水原理，提出了一种将环境水汽自动补充至恒湿文物展柜系统水箱的方法，并搭建了相应的小型空气取水装置，证明了该方法的可行性；同时，构建了传热传质耦合的空气取水装置数学模型，在获取环境温湿度对装置取水量的影响规律后，分析加热功率和吸附床结构对装置单位能耗取水量的影响；此外，为便于装置的后期推广应用，提出了两个基于吸附床高度和直径的量纲为1参数。结果表明：进口空气的温度对取水量影响较小，但进口空气的湿度对取水量影响较明显，取水量随着湿度增加而增加；加热功率存在最优值，单位能耗取水量随着加热功率先增大后减小；在当前几何参数组合下，两个量纲为1参数η=2、β=4时，装置的单位能耗取水量最高。     

Developing novel liquid crystal technologies for display and photonic applications

Modern liquid crystal displays (LCDs) require novel technologies, such as new alignment methods to eliminate alignment layers, fast response and long operation time. To this end, we report an overview of recent efforts in LCD technologies devoted to realize more display modes having no alignment layer, faster switching time and low battery consumption. In particular, we overview recent advances on the liquid crystals (LCs) alignment for display applications, which includes superfine nanostructures, polymeric microchannels and polymer stabilized LCs. Furthermore, we analyze the main optical and electro-optical properties of new generation LCDs displays addressing a particular attention to LCs blue phase hosting gold nanoparticles. Moreover, we focus on the progress of electrofluidic displays, which demonstrates characteristics that are similar to LCDs, with attention on various pixel designs, operation principles and possible future trends of the technology.     

Design,characterization and control of SMA springs-based multi-modal tactile display device for biomedical applications

Tactile display is recently attracting much attention in the field of human–computer interaction. There is a strong need for such a device especially for applications in which the touch feeling is lost, such as surgeons who are willing to feel the tissue hardness during laparoscopic surgeries. In this paper, a novel multi-modal tactile display device which can display both surface shape and stiffness of an object is introduced. The conceptual design is built upon using two springs, made of Shape Memory Alloys (SMA), for displaying shape and stiffness. The design parameters of this device are selected based on the spatial resolution of human finger and the elasticity range of the soft tissue. The display device is simulated using Finite Element Method (FEM) to study the effect of design parameters on the resulting stiffness. Simulation results show that the device can display stiffness of an object independent of its shape display. The experimental setup is built and used for the characterization and control of the SMA springs. Experimental results show that the device can display a stiffness range of (35–110) N/m and elongation up to 5 mm.     

Discomfort luminance level of head-mounted displays depending on the adapting luminance

The Images in an immersive head-mounted display (HMD) for virtual reality provide the sole source for visual adaptation. Thus, significant, near-instantaneous increases in luminance while viewing an HMD can result in visual discomfort. Therefore, the current study investigated the luminance change necessary to induce this discomfort. Based on the psychophysical experiment data collected from 10 subjects, a prediction model was derived using four complex images and one neutral image, with four to six levels of average scene luminance. Result showed that maximum area luminance has a significant correlation with the discomfort luminance level than average, median, or maximum pixel luminance. According to the prediction model, the discomfort luminance level of a head-mounted display was represented as a positive linear function in log₁₀ units using the previous adaptation luminance when luminance is calculated as maximum area luminance.