Synthesis and evaluation of several high absorbance black pigments for spacecraft thermal control coatings

Using black coatings and materials with high light absorbance that are capable of absorbing photons at visible and longer wavelengths is a very effective way to reduce unwanted stray light, also known as optical noise, within optical equipment. These lights can be greatly reduced to a reasonable level by functional and performable black coatings that are modified to absorb incident light as much as possible by their specific pigments. In the present work, several carbonaceous pigments were synthesized for the first time from wasteful materials and their optical properties in the visible and near‐infrared ranges studied. First, MCM‐48 and SBA‐15 were synthesized at different conditions and were then used as templates for carbonaceous products. SSS‐1 (the carbonic pigment synthesized by the mixture of sucrose and sodium silicate), SSS‐2 (the carbonic pigment synthesized by the mixture of sawdust and sodium silicate), and mesoporous carbon pigments (CMK‐3 and CMK‐1 with different levels of saturations) were synthesized. Finally, their structure, morphology, and optical properties were investigated by X‐ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE‐SEM), and Diffuse Reflectance Spectroscopy (DRS). The results indicated that the SSS‐1 pigment had a lower reflectance (below 1%) than carbon black (about 2.5%) in the visible region despite it being more cost‐effective than carbon black. The mesoporous pigments showed very high light absorbance in the visible region (about 2.5%). Compared with other black pigments, the CMK‐1 was the blackest synthesized material with a very low reflectance (about 0.05% in visible region), making it an ideal candidate as a super black pigment for reducing unwanted stray light within optical equipment.     

Dual-activator luminescence of LuAG:Mn4+/Tb3+ phosphor for optical thermometry

Mn⁴⁺ and Tb³⁺ singly doped and Mn⁴⁺/Tb³⁺ codoped lutetium aluminum garnet (Lu₃Al₅O₁₂, or simply LuAG) phosphors were synthesized and investigated for the application of optical thermometry. X-ray powder diffraction and luminescence spectroscopy measurements were performed on all samples to analyze their crystal phases and optical properties. In particular, temperature-dependent luminescence of the LuAG:Mn⁴⁺/Tb³⁺ sample was measured at the temperature range of 270–420 K. The results showed that the luminescence intensity of Mn⁴⁺ has gone through a remarkable decline while the luminescence of Tb³⁺ has an only insignificant change with the rise of temperature which leads to a dramatic decrease in the fluorescence intensity ratio (FIR) between the two activator Mn⁴⁺ and Tb³⁺. Further analysis showed that the LuAG:Mn⁴⁺/Tb³⁺ sample used for temperature sensing has a high relative sensitivity with maximum value of 4.3% K⁻¹ at 333 K. Our research indicated that this LuAG:Mn⁴⁺/Tb³⁺ material is a promising candidate for FIR-type optical temperature sensing.     

光学球罩数控抛光工艺关键技术研究

光学球罩被广泛应用于各类光电系统中,其面形精度制约着光电系统的成像质量。随着数控技术的发展,数控加工技术逐渐成为目前光学加工行业的主流发展方向。基于高质量的铣磨表面,为了能够在准球心高速抛光工艺中实现等去除量加工,本文对同步抛光技术进行了理论分析及数学模型推导,并通过实验证明,同步抛光技术可以有效地提升加工效率,获得高质量的光学表面。     

新型建筑工业化与BIM 技术的协同关系分析

本文主要以新型建筑工业化与BIM技术的协同关系分析为重点阐述,结合当下建筑工业化和BIM技术两者关系、新型建筑工业要点、BIM技术基本作用和BIM技术和新型建筑工业化协同关系为主要依据,从能够创建关系矩阵、两者协同关系解释这几方面进行深入探索与研究,其目的在于加强BIM技术在新型建筑工业化中的运作效率。     

Embedded Metal Oxide Plasmonics Using Local Plasma Oxidation of AZO for Planar Metasurfaces

New methods for achieving high-quality conducting oxide metasurfaces are of great importance for a range of emerging applications from infrared thermal control coatings to epsilon-near-zero nonlinear optics. This work demonstrates the viability of plasma patterning as a technique to selectively and locally modulate the carrier density in planar Al-doped ZnO (AZO) metasurfaces without any associated topographical surface profile. This technique stands in strong contrast to conventional physical patterning which results in nonplanar textured surfaces. The approach can open up a new route to form novel photonic devices with planar metasurfaces, for example, antireflective coatings and multi-layer devices. To demonstrate the performance of the carrier-modulated AZO metasurfaces, two types of devices are realized using the demonstrated plasma patterning. A metasurface optical solar reflector is shown to produce infrared emissivity equivalent to a conventional etched design. Second, a multiband metasurface is achieved by integrating a Au visible-range metasurface on top of the planar AZO infrared metasurface. Independent control of spectral bands without significant cross-talk between infrared and visible functionalities is achieved. Local carrier tuning of conducting oxide films offers a conceptually new approach for oxide-based photonics and nanoelectronics and opens up new routes for integrated planar metasurfaces in optical technology.     

一种基于LTCC基板的数字光收发模块设计

首先介绍低温共烧陶瓷(LTCC)技术和数字光收发模块,阐述LTCC的技术特点、工艺流程以及它相较于传统PCB电路基板的优势,解释了数字光收发模块的通信原理和工作方式;其次,提出了一种基于LTCC电路基板的数字光收发模块的设计方案,详细介绍了该光模块的主要构成和实现方法,包括电路设计和关键器件的比较和选取;最后,通过对该方案所述的数字光收发模块的样件进行关键指标和性能测试,验证了该设计方案的可行性。     

某铁矿隔水护顶矿柱厚度计算及安全影响预测

科学合理地确定矿山隔水护顶矿柱安全厚度是矿山安全生产的前提条件，为保障某铁矿地表民房、道路等建（构）筑物安全，防止矿山开采过程中产生的导水裂隙带贯通第四系含水层，采用荷载传递交汇线法、K.B.鲁别涅依他估算法和冒落带、导水裂隙带高度估算法3种理论分析方法对隔水护顶矿柱厚度进行计算，并利用数值模拟手段对留设隔水护顶矿柱后的开采过程安全影响进行了分析，对理论计算结果进行了验证。3种理论计算方法得出的隔水护顶矿柱厚度分别为14.3～17.3 m、17.5～31.4 m和41.8～57.4 m，推荐隔水护顶矿柱留设厚度为60 m。通过数值模拟分析得出，在留设60 m厚的隔水护顶矿柱的基础上，开采区域和隔水护顶矿柱位置产生的最大拉应力约0.47 MPa，矿山开采不会对隔水护顶矿柱造成破坏；地表产生的最大水平位移约5.8 cm，最大垂直位移约26.5 cm，最大倾斜为1.70 mm/m，最大曲率为0.20 mm/m2，最大水平变形值为0.70 mm/m，满足相关规范要求，预测矿山开采不会造成地表建（构）筑物破坏。     

Dynamic response of ferrofluidic deformable mirrors using elastomer membrane and overdrive techniques

The experimental results obtained with a ferrofluidic deformable mirror controlled by electro-magnet actuators are presented here. Using a step input through a single actuator, we obtained a steady-state settling time of 100?ms; however, different combinations of overdrive inputs can be used to decrease it to 25?ms. A new technique which consists of laying down an elastomer membrane, coated with an aluminum film, on the ferrofluid is also discussed. By adding the membrane on the ferrofluid, it further decreases the time response by a factor of 2. Furthermore, the thin aluminum layer improves the reflectivity of the mirror. Finally, using the membrane and the overdrive techniques combined, the time response is improved by a factor of 20. Numerical simulations show that ferrofluidic mirrors using membranes and improved electronics should reach settling times of the order of a millisecond. Presumably, even lower settling times could be possible.     

新型建筑材料在建设工程中应用与发展趋势

随着我国改革开放不断深入,科技水平的不断提升,人们对美好生活的追求,促使建筑材料飞速发展,以适应环保、节能、轻质、安全、高效的需求,从而取代能耗多、污染大、防火等级低不安全的建筑材料。本文例举了当前一些新型建筑材料的应用特点,并阐述了新型建筑材料的发展趋势。