超声波淬火在30CrMnTi钢耳轴热处理中的应用

对30CrMnTi钢耳轴的超声波淬火工艺进行了研究,并对耳轴的显微组织和力学性能进行了分析。结果表明,耳轴的表面硬度和裂纹形成概率随着超声波涡流压力的升高而增加,而冲击性能和弯曲畸变量随着涡流压力的升高而下降,在3 MPa的涡流压力下,耳轴在20号机械油中的冷却特性接近于水淬,此时耳轴的淬硬层深为24 mm,显微组织是板条状马氏体。     

动态小张力测量的机械振动噪声补偿

在细纱动态小张力测量时,由于张力信号十分微弱,容易被测量环境的机械振动噪声所淹没。能否消除振动噪声,关系到小张力测量的成败。建立了在振动环境下电阻应变传感器的数学模型,仿真研究了振动噪声对测量的影响,提出了硬件补偿和软件滤波相结合的振动噪声补偿方案。最后用高精度放大器和数字信号控制器实现了振动噪声的补偿,实验结果证明了该方法的有效性。     

Potential method in the theory of thermoviscoelastic mixtures

In this article, the linear theory of binary thermoviscoelastic mixtures is considered and the basic boundary value problems (BVPs) of steady vibrations are investigated. Namely, the fundamental solution of the system of equations of steady vibrations is constructed explicitly and its basic properties are established. Green’s second and third identities are obtained and the uniqueness theorems for classical solutions of the internal and external basic BVPs of steady vibrations are proved. The surface and volume potentials are constructed and their basic properties are given. The determinants of symbolic matrices are calculated explicitly. The BVPs are reduced to the always solvable singular integral equations for which Fredholm’s theorems are valid. Finally, the existence theorems for classical solutions of the internal and external BVPs of steady vibrations are proved by the potential method and the theory of singular integral equations.     

Metal-loaded polyol-montmorillonite with improved affinity towards hydrogen

Metal-organoclays (MOC) were prepared through incorporation of Boltorn polyol dendrimer H30 in Na⁺-exchanged montmorillonite (NaMt), followed by in-situ dispersion of Cu⁰ and Pd⁰ nanoparticles (CuNPs and PdNPs). The organoclays displayed high CO₂ retention capacity (CRC) of 3.6–11.1 μmol/g, but metal incorporation induced a significant increase of hydrogen uptake up to 51.8–508.2 micmol/g at the expense of the CRC. Thermal programmed desorption and FT-IR investigations revealed strong interactions with CO₂ before metal incorporation. These interactions markedly depleted in the presence of CuNPs and PdNPs. This was regarded as a precise indicator of the appreciable metal stabilization within the organic entanglement, due to enhancements of HO:Cu⁰ and HO:Pd⁰ interactions at the expense of HO:CO₂ carbonate-like association. The CO₂ and H₂ retention capacities (CRC and HRC, respectively) were found to strongly correlate to the number of OH groups of the dendritic moiety incorporated. Hydrogen retention appears to involve mainly physical interactions as supported by easy gas release between 20 °C and 75 °C or even at room temperature under vacuum. This demonstrates unequivocally the reversible capture of hydrogen. The increase of the hydrogen uptake with increasing contact time provides evidence of the occurrence of diffusion phenomena. This was not observed with CO₂ before metal incorporation, suggesting a structure compaction that improves metal stabilization. This opens new prospects for hydrogen storage via truly reversible capture on low cost clay materials and biodegradable hyperbranched macromolecules deriving from plants.     

盐生杜氏藻软胶囊中β,β-胡萝卜素几何异构体组成的测定

采用C30-HPLC-PDA-ELSD系统,参照已公布的全反式异构体的吸光系数(Al1%cm=2500),根据β,β-胡萝卜素顺式异相体电子吸收光谱峰面积与ELSD质量峰面积之比,估算出9-和13-顺式异构体的吸光系数分别为2018和1990.根据其色谱峰面积,可以准确测量出盐生杜氏藻软胶囊中β,β-胡萝卜素几何异构体的组成.     

Precipitate Behavior in Fe–20Cr–30Ni–2Nb Austenitic Heat-Resistant Steel

In this study,the precipitation behavior of a new austenitic heat-resistant steel(Fe–20Cr–30Ni–2Nb,in at%)was investigated.The effects of alloying addition of boron(B) and lanthanum(La) on the microstructure of the austenitic steel were scrutinized using SEM,EPMA,TEM,and XRD.The results showed that the addition of B enhanced the precipitation of bar-type Laves phase.A small precipitate with high La concentration was observed at the grain boundary in the alloy without aging;similar precipitates without La also presented in region adjacent to the La single phase.This result indicates that La can exist independently and does not contribute to the formation of new compounds.However,in both Band La-modified alloy,B appeared in the precipitate free zone.In the alloy containing both B and La,only Fe2 Nb Lavesphase precipitates,as indicated by the XRD result.     

BRIJ30模板剂对镍钼超细催化剂加氢脱芳烃性能的影响

在超细NiO-MoO₃/TiO₂-SiO₂催化剂制备过程中引入模板剂聚氧乙烯十二烷基醚(BRIJ30),采用TG-DTA考察模板剂的脱除,采用N₂吸附-脱附、XRD、HRTEM分析考察模板剂对催化剂的物化性质、结构特性的影响。采用微型固定床反应装置,以航空煤油为原料进行加氢脱芳烃反应,考察催化剂的催化活性和稳定性。结果表明,引入模板剂BRIJ-30所制备的NiO-MoO₃/TiO₂-SiO₂催化剂的比表面积明显扩大,孔结构改善,加氢脱芳烃活性提高。     

Microstructure and hydrogen permeability of Nb40Hf30Ni30 ternary alloy

The microstructure and hydrogen permeability of the Nb₄₀Hf₃₀Ni₃₀ ternary alloys were investigated in particular. The as-cast Nb₄₀Hf₃₀Ni₃₀ alloy consists of the bcc- (Nb,Hf) solid solution, the B_f-HfNi compound and the fine eutectic phase of {(Nb,Hf) + HfNi}. The annealed Nb₄₀Hf₃₀Ni₃₀ alloy consists of the bcc-(Nb, Hf) solid solution and the fine eutectic phase of {(Nb,Hf) + HfNi}. The as-cast Nb₄₀Hf₃₀Ni₃₀ alloy shows a high Φ value of 4.3 × 10⁻⁸ [mol H₂ m⁻¹ s⁻¹ Pa^−0.5] at 673 K, and for the annealed Nb₄₀Hf₃₀Ni₃₀ alloy, the Φ value is 3.8 × 10⁻⁸ [mol H₂ m⁻¹ s⁻¹ Pa^−0.5] at 673 K. Annealing can’t enhance the hydrogen permeability of the Nb₄₀Hf₃₀Ni₃₀ ternary alloy.     

基于dsPIC30F的电动纠偏系统的设计

跑偏是带材传输中很普遍的现象.针对带材收卷过程中的偏差问题,介绍一种基于dsPIC30F的以线性CCD作为传感器、以电机和纠偏辊为执行机构的电动纠偏伺服系统,阐述其原理、结构和软硬件设计.该纠偏装置具有纠偏方式多样性、精度高、实时性高的特点.试验表明该系统工作稳定,纠偏效果明显,适用于各种纠偏的场合.     

热处理对Ti30Nb5Ta6Zr合金组织和力学性能的影响

根据β稳定化系数kβ和d-电子理论设计了低弹性模量、中高强度、良好塑性和生物相容性的新型牙科种植用近β型Ti30Nb5Ta6Zr合金,研究了合金在β相区固溶和时效处理后组织和力学性能的变化规律。结果表明,在β相区固溶水淬后组织为亚稳β相。低温时效时析出ω相,随着时效温度的升高,逐渐析出α相。合金的强度和弹性模量随时效温度的升高先升高后下降;延伸率先降低后升高。合金在800℃固溶+500℃时效后综合力学性能优良,可以满足牙科植入要求。