5 000 t公务船调距桨桨叶数选型研究

针对国内外调距桨桨叶数选型依靠经验为主，对不同桨叶数对推进器整体性能的影响始终缺乏定量分析的现状，以某5 000 t公务船为目标船型，通过调距桨分别配置不同的桨叶数，分析不同桨叶数对目标船型综合性能的影响。总结了公务船调距桨桨叶数选型的方法，归纳了不同叶数调距桨的优劣，可为后续新造船桨叶数的选取提供参考。     

Durable,Sensitive, and Wide‐Range Wearable Pressure Sensors Based on Wavy‐Structured Flexible Conductive Composite Film

Flexible pressure sensors have potential applications in human motion monitoring and electronic skins. To satisfy the practical applications, pressure sensors with a high sensitivity, a low detection limit, a broad response range, and an excellent stability are highly needed. Here, a piezoresistive pressure sensor based on wavy‐structured single‐walled carbon nanotube/graphite flake/thermoplastic polyurethane (SWCNT/GF/TPU) composite film is fabricated by a prestretching process. Due to the random wavy structure, high conductivity, and good flexibility, the prepared sensor displays a low detection limit of 2 Pa, a wide sensing range of 0–60 kPa, and a high sensitivity of 5.49 kPa^?1 for 0–50 Pa. Furthermore, the sensor shows a remarkable repeatability of over 1.1 × 10⁴, 9.0 × 10³, and 2.0 × 10³ pressure loading/unloading cycles at 50 Pa, 500 Pa, and 30 kPa, respectively, and a fast responsibility of 100–150 ms of loading response time and 400–600 ms of relaxation time. Therefore, the pressure sensor is successfully adopted to monitor both the large‐scale human activities (e.g., walk and jump) and the small‐scale signals (e.g., wrist pulse). Furthermore, a sensor array is assembled to map the weight and shape of an object, indicating its various potential applications including human–machine interactions, human health monitoring, and other wearable electronics.     

CH870圆锥破碎机的技改实践

重点介绍了研山铁矿中碎系统使用的4台CH870圆锥破碎机在运转过程中存在的问题及相关解决措施。通过采取“竖直圆筒给料法”、优化衬板腔型、改善防尘桶以及开发油箱仪表TIMS系统等措施，确保了CH870圆锥破碎机的良好运行，保证了破碎工序的生产和成本指标的完成。     

Structure,properties, and applications of polyacrylonitrile/carbon nanotube (CNT) fibers at low CNT loading

Bi-component, polyacrylonitrile (PAN)/carbon nanotube (CNT) fibers were processed, at different core-sheath area ratios, by gel spinning. A percolated CNT network at 10 wt% CNT in the sheath enhanced electrical conductivity as compared to the neat PAN fiber, while PAN polymer in the core contributed to the good mechanical properties. Fibers with relatively thin sheath allowed overall CNT loading as low as 3.7 wt% to be made with good electrical conductivity, and PAN stabilization by Joule heating was demonstrated. Such fibers with combined good mechanical properties and electrical conductivity can also potentially be used for electrical heating of fabrics, for making smart textiles, and for electromagnetic interference shielding.     

A universal HF-free synthetic method to highly efficient narrow-band red-emitting A2XF6:Mn4+ (A = K,Na, Rb,Cs; X = Si,Ge, Ti) phosphors

Mn⁴⁺-activated fluoride red-emitting narrow-band phosphors have been successfully used in wide color-gamut white LEDs for liquid crystal display (LCD) backlights. However, highly concentrated and toxic HF is usually used in their synthesis, causing environment and safety issues. In this work, we proposed a HF-free green method, that is, using NH₄F/HCl instead of HF, to synthesize a series of A₂XF₆:Mn⁴⁺ (A = K, Na, Rb, Cs; X = Si, Ge, Ti) phosphors. The microstructure, photoluminescence (PL) properties, thermal quenching, and applications of the synthesized phosphors were investigated. Using the proposed approach, the phosphors generally showed a pure phase, a particle size ranging from 5 to 45 μm, and some characteristic sharp emission lines of Mn⁴⁺ in the red spectral range. The internal quantum efficiency was varied in a broad range of 69%-94% under the 460 nm excitation, depending on the composition of the fluoride host. Among these compositions, K₂XF₆:Mn⁴⁺ (X = Ge and Ti) phosphors even had a similar external quantum efficiency (>60%) with commercial ones. By combining K₂GeF₆:Mn⁴⁺ (narrow-band red) and β-sialon:Eu²⁺ (narrow-band green) with a blue LED, a white light-emitting diode (wLED) backlight with a color gamut of 87.7% National Television System Committee Standard, color temperature of 8423 K, and a luminous efficacy of 110.8 lm/W was demonstrated. These results indicate that the synthetic method proposed in this work is universal for preparing highly efficient fluoride phosphors used in wLEDs.     

Formation mechanism and microstructure evolution of Ba2Ti9O20 ceramics by reaction sintering method

Ba₂Ti₉O₂₀ single-phase ceramics were prepared by reaction sintering method using TiO₂ and BaCO₃ as raw materials after heat treating at 1150°C for 10 hours. Furthermore, the formation mechanism and microstructure evolution of Ba₂Ti₉O₂₀ ceramics prepared by reaction sintering method were investigated. The formation behavior of Ba₂Ti₉O₂₀ phase was analyzed from the perspective of diffusion, where the reaction activation energy required for the process was calculated to be about 386.17 kJ/mol. Combined with the scanning electron microscopy and the energy dispersive spectrometer, it was revealed that the pores on Ba₂Ti₉O₂₀ grains in the process of reaction sintering might be caused by the absence of oxygen element. Meanwhile, the reason for the roughness of ceramic surface was that the local inhomogeneous distribution of barium on the surface of Ba₂Ti₉O₂₀ grain leaded to the enrichment of titanium.     

Neoteric Mn2+-activated Cs3Cu2I5 dazzling yellow-emitting phosphors for white-LED

Neoteric Mn²⁺-activated Cs₃Cu₂I₅ yellow-emitting halides were achieved by the simple solid-state reaction route. The near-ultraviolet light was the suitable excitation lighting source for the resultant halides. The resultant halides exhibited bright yellow emission under the excitation of 378 nm and the optimum dopant content was 11 mol%. The multipole-multipole interaction contributed to the concentration quenching mechanism and the critical distance was 28.65 Å. The thermal resistance of the prepared compounds was identified by the temperature-dependent emission spectra. Ultimately, the designed light-emitting diode showed bright white light with satisfied color rendering index, proper color coordinate, and suitable correlated color temperature. These results indicated that the prepared yellow-emitting halides were suitable for indoor illumination.     

Investigation on effects of adapting chromaticities and luminance on color appearance on computer displays using memory colors

CAT02, the most widely used chromatic adaptation transform to characterize the chromatic adaptation mechanism in the human visual system, includes a factor D to characterize the degree of chromatic adaptation. This factor, however, is only determined by the luminance level of the adapting field and surround. This study was designed to investigate how the change of adapting chromaticities and the simultaneous changes of adapting chromaticities and luminance affect the degree of chromatic adaptation and color appearance on computer displays. The human observers adjusted the color appearance of various familiar objects and cubes on different display backgrounds. A higher degree of chromatic adaptation was found when using familiar objects, which was likely due to the cognitive mechanism. Both the adapting chromaticities and luminance significantly affected the degree of chromatic adaptation, with a lower degree under an adapting condition with a lower adapting correlated color temperature and a lower adapting luminance. In addition, the effect of adapting luminance on colorfulness (known as the Hunt Effect) was likely to be overpredicted in CAM02-UCS, which merits further investigations.     

铜山口铜矿水力旋流器数值优化试验研究

为提高大冶有色铜山口铜矿选矿厂FX500水力旋流器的分级精度、降低底流夹细量，通过数值模拟方法系统考察了旋流器结构参数和操作参数对旋流器分离性能的影响，结果表明：①适当增加入口流速、降低给矿浓度，可从整体上降低底流夹细量和溢流跑粗量；②适当增大柱段高度和小锥锥角，可进一步降低底流夹细量；③适当增大沉砂口上锥角角度，对底流中的微细粒级有洗涤作用，能进一步降低底流夹细量；④现场对比试验证实，旋流器结构优化后底流-75 μm粒级夹细率下降了1.78个百分点。研究结果为铜山口铜矿水力旋流器的优化与改造提供了技术支撑。