TMCP工艺下Ti-Mg氧化物冶金钢轧态组织性能

摘要：为研究轧制过程中氧化物粒子对母材组织性能的影响，提出了一种只在再结晶区进行轧制的新工艺路线，利用常规冶炼及氧化物冶炼的实验钢分析其轧态显微组织、力学性能及相变过程。结果表明：在新轧制工艺下，氧化物冶金钢母材显微组织由常规的贝氏体板条束变为针状铁素体，其基体具有良好的力学性能，-80℃冲击韧性达149J；热轧工艺下的组织转变分两阶段进行，初期是针状铁素体的形核和晶粒细化，之后贝氏体相变被限制在针状铁素体板条间构成的区域内。     

Some physiological characteristics to estimate species potential as a mine reclamation ground cover

In finding what physiological characteristics can be used to predict ground cover success on mine reclamation sites, 14 herb and grass species were tested. Establishment and early growth was tested on three different soils, ie vermiculate and quartz sand mixture, quarry overburden and coal mine overburden in a greenhouse. The results indicate that plant height and cover, transpiration rate and foliar pigments may be used to select plant adaptability to mined soil. White clover (Trifolium repens L.) showed the greatest potential as ground cover for mined soils. Species most widely used in reclamation tended to be perennials of moderate rate.     

菱铁矿直接还原-低阶煤提质一体化扩大试验

摘要：菱铁矿作为中国重要的铁矿资源，因具有“贫、细、杂”的特点，常规选矿工艺无法对其进行有效分选；此外，中国低阶煤通常被用作低级燃料直接燃烧使用，导致大气污染严重。因此，开发复杂难选铁矿石及低阶煤资源高效清洁利用新技术，将具有重要现实意义。以难选的低品位菱铁矿和难利用低阶煤为对象，开展菱铁矿直接还原与低阶煤提质一体化扩大试验研究。以神府烟煤为还原剂，在直接还原温度为1050℃，时间为120min，C/Fe质量比为250，脱硫剂配比为6%，干式磁选磁场强度为015 T，一段磨矿细度小于0074mm占50%左右，湿式磁选磁场强度为008 T，二段磨矿细度小于0074mm占90%左右，磁选磁场强度为0043 T的条件下，可获得直接还原铁（DRI）粉铁品位9103%、铁总回收率8133%的良好指标；同时每吨DRI固定碳质量分数为7611%的半焦产品产出率为1340kg，其质量达到工业及民用燃料兰炭Ⅰ级品标准。在煤基直接还原工艺中一步成功实现低阶煤半焦化提质和铁矿直接还原，不仅可制备电炉炼钢原料，还可以生产新型的清洁燃料半焦。     

New environmental-friendly yellow pigments Y_(4-x)A_xMoO_(9+δ)(A =Ta,Tb)

A series of inorganic yellow pigments with general formula Y_(4-x)A_xMoO_(9+δ)(A = Ta, Tb), where x = 0,0.05,0.1,0.2, 0.4 for Ta and χ = 0, 0.005, 0.01.0.03, 0.05 for Tb,were synthesized by a conventional ceramic method at 1400 ℃ for 6 h in air. The samples were characterized by XRD,EDS,XPS,SEM,TG-DSC,UV-vis-NIR reflectance spectroscopy and CIE L*a*b* color scales. It is found that the substitution of A(A = Ta, Tb) for Y~(3+) in Y_4 MoO_9 decreases the NIR reflectance of the pigment samples, but the developed pigments Y_(4-x)A_xMoO_(9+δ)(A = Ta, Tb) still exhibit impressive NIR solar reflectance. The brighter yellow color of inorganic pigments Y_(4-x)A_xMoO_(9+δ)(A = Ta, Tb) is available when x is about 0.1 for Ta and 0.01 for Tb. The results make them a series of potential candidates as ecological yellow pigments because of their high reflectance, lightness, intense coloration and excellent thermal and chemical stability.     

面向Ad Hoc网络的无证书认证组密钥协商协议

安全和效率是影响无证书认证组密钥协商协议能否在Ad Hoc网络中得到实际应用的两个关键因素。针对这两个关键因素，以提高Ad Hoc网络安全组通信的安全性和效率为目标，提出一个无证书认证组密钥协商协议，基于椭圆曲线密码体制（ECC）点乘运算实现无配对的无证书认证组密钥协商和身份认证；并使用Huffman密钥树优化通信轮数，以降低计算量和通信量，提高组密钥协商效率。安全分析和性能分析表明，与现有基于无证书的组密钥协商协议相比，所提方案在组密钥协商时具有较高的效率和安全性，可以满足资源受限条件下组密钥建立以及组成员变动带来的密钥更新问题。     

Freeze-drying and mechanical redispersion of aqueous PEDOT:PSS

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films are attracting famous applications in antistatic coating, energy storage and conversion, printed electronics, and biomedical fields due to their conductivity, optical transparency and flexibility. However, PEDOT:PSS has poor dispersion stability during long-term storage and transport. Moreover, the dried PEDOT:PSS films are insoluble in any solvent and cannot be redispersed again. In comparison to bake drying, here, a feasible strategy to achieve mechanically redispersed PEDOT:PSS with the help of freeze-drying process was reported. The redispersed PEDOT:PSS can recover not only the initial characters such as pH, chemical composition, viscosity, and particle size under similar solid contents, but also conductivity and surface morphology of treated films. In addition, the treated film exhibits self-healing properties similar to pristine film in terms of mechanical and electrical properties. This technology enables reuse and overcomes the technical problems of PEDOT:PSS dispersion, realizing real-time processing to meet variable applications.     

The effect of Nd3+ concentration on fabrication,microstructure, and luminescent properties of anisotropic S-FAP ceramics

Nd³⁺ doped strontium fluorophosphate (S-FAP), with chemical formula Sr₅(PO₄)₃F, nanopowders were prepared using the co-precipitation method. The prepared powders had no impurity phase with a grain size of about 30 nm and the doping limit of Nd³⁺ ions in strontium fluorophosphate is about 9 at.%. The morphology and particle size were determined by the doping concentration of Nd³⁺. Anisotropic Nd: S-FAP transparent ceramics with different Nd³⁺ doping concentrations were fabricated successfully by the simple hot-pressing method. The grain size of prepared S-FAP transparent ceramics decreased first and then increased with the increase of Nd³⁺ concentration. The 2 at.% Nd: S-FAP ceramic presented the highest optical transmittance at all wavelengths range. The characteristic transitions from the ground state to the excited states of Nd³⁺ ions were observed from the absorption spectra, and the absorption cross-section was calculated at 3.71 × 10^–20 cm². The influence of Nd³⁺ ion concentration on luminescence intensity and fluorescence lifetime was studied under 796 nm excitation. The strong emission of ⁴F_3/2→⁴I_9/2 transition in Nd: S-FAP was calculated by Judd–Ofelt (J-O) theory.     

Improving the corrosion resistance of a-C:H film by a top a-C:H:Si:O layer

During the deposition of a-C:H film, defects (pinholes or discontinuities) caused by excessive stress will inevitably appear, which will reduce the corrosion resistance of the a-C:H film. In this study, top a-C:H:Si:O layers (thickness of approximately 0.3 μm) on the surface of a-C:H films were deposited on a large scale by PACVD technology using acetylene (C₂H₂) and/or hexamethyldisiloxane (HMDSO) as reactants, to improve the corrosion resistance of a-C:H films while ensuring the appropriate overall hardness of the films. The corrosion behaviors of the films were studied by electrochemical impedance spectroscopy (EIS) and Tafel polarization. We found that the a-C:H/a-C:H:Si:O films possess a lower electrolyte penetration rate due to their stronger capacitance characteristics. In addition, the corrosion current density of the a-C:H/a-C:H:Si:O films (10^?10 A cm^?2) were reduced by 2 orders of magnitude compared to the a-C:H film (10^?8 A cm^?2), and by 3 orders of magnitude compared to 316 stainless steel (10^?7 A cm^?2). The impedance results obtained by EIS were simulated using appropriate equivalent circuits, and the corresponding electrical parameters were used to further verify the electrochemical protection behavior of the top a-C:H:Si:O layer.     

Research and development of liquid hydrogen (LH2) temperature monitoring system for marine applications

Monitoring the temperature in liquid hydrogen (LH₂) storage tanks on ships is important for the safety of maritime navigation. In addition, accurate temperature measurement is also required for commercial transactions. Temperature and pressure define the density of liquid hydrogen, which is directly linked to trading interests. In this study, we developed and tested a liquid hydrogen temperature monitoring system that uses platinum resistance sensors with a nominal electrical resistance of approximately 1000 Ω at room temperature, PT-1000, for marine applications. The temperature measurements were carried out using a newly developed temperature monitoring system under different pressure conditions. The measured values are compared with a calibrated reference PT-1000 resistance thermometer. We confirm a measurement accuracy of ±50 mK in a pressure range of 0.1 MPa–0.5 MPa.     

Evaluation of particle recovery from microalgae

Coccoliths are micro-structured biomineral particles found in cell protective covering layers of coccolithophore species. They are mainly composed of CaCO₃ and their individual crystal entities are arranged in such a way that they construct complex and unique structures. This complexity is found down to the individual particle level and appears to have promising properties to offer. This study focuses on the essential step prior to any kind of implementation, which is the recovery of the material. It summarizes cleaning protocols found in literature, compares them for the first time for the same freshly cultivated material and addresses challenges that still need to be overcome. Further, it highlight the advantages and disadvantages of the best cleaning protocols, suggests optimizations with promising results and uses size distribution measurements to analyse the recovery efficiency. To that end, further characterization techniques, new for coccoliths, are introduced and used to improve our current knowledge of the particles behaviour.