Dy0.6Tb0.3Pr0.1(Fe0.95Mn0.05)x取向晶体的结构与磁致伸缩

采用Ｃｚｏｃｈｒａｌｓｋｉ方法生长了Ｄｙ０．６Ｔｂ０．３Ｐｒ０．１（Ｆｅ０．９５Ｍｎ０．０５）ｘ（１．８５≤ｘ≤１．９５）取向合金。所有合金主相为立方Ｌａｖｅｓ相结构,择优取向不完整择优取向的方向与Ｘ的大小有关。研究了沿着这些样品的生长方向的磁致伸缩性能以及磁致伸缩性能与压力之间的关系。     

La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的储氢性能研究

针对两种新型稀土型储氢合金La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2的储氢特性进行研究分析。实验表明,相同温度下,La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的PCT曲线基本重合,且都具有优良的吸氢动力学性能;相比之下,后者的滞后系数要小于前者,吸氢量较大,吸氢速率也较快,故其储氢性能较优。300次吸放氢循环实验结果表明,La0.5Y0.5Ni4.8Al0.2合金的吸氢动力学性能虽然略有下降,但抗粉化性能较好。     

Thermal Stability of Amorphous Hydride Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45)

The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre-sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction(XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were preparedby mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas-eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most oftheir hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. Thecrystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphousMg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep-tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on thecrystallization of amorphous alloys was discussed.     

Plasma surface treatments of poly(l-lactic acid) (PLLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)

The surfaces of poly(l-lactic acid) (PLLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) were modified by oxygen and nitrogen plasma treatments. The physical and chemical surface characteristics were evaluated by contact angle tests, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The plasma treatments caused an increase in both contact angle and roughening, altered the surface morphology, inserted polar groups, and, consequently, enhanced the hydrophilicity for both PLLA and PHBV polymers.     

Acousto-optic interaction in alpha-BaB(2)O(4)and Li(2)B(4)O(7) crystals

Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals.     

Poly(thiophenylanilino) and poly(furanylanilino) polymers

Novel hybrid polymers with thiophenylanilino and furanylanilino backbones and substituted phenyl side groups are reported. The new monomers bis-(4-heterocyclic-2-yl-phenyl)-aryl-amine (heterocyclic = thiophen with aryl = 4-benzoyl (2a), 4-nitro-phenyl (2b) and furan with aryl = 4-benzoyl-phenyl (3a), 4-nitro-phenyl (3b)) were prepared by monosubstituting triphenylamine under electrophilic aromatic conditions affording 4-nitrotriphenylamine and 4-benzoyltriphenylamine. Di(bromination) of the latter compounds followed by Stille cross-coupling reactions with 2-tributylstannylthiophene or 2-tributylstannylfuran produces the new monomers 2a–b and 3a–b in high yield. The monomers are electrochemically polymerized at relatively low potentials (<0.8 V versus Ag⁺/AgCl) in acetonitrile electrolytes resulting in electroactive films. All the new polymers can be repeatedly oxidized and reduced with little loss of electrochemical activity. Vibrational spectroscopy reveals that the monomer units are connected predominately via coupling of the thiophenyl or furanyl rings yielding the novel polymers. Single-crystal molecular structure determinations of 4-nitrotriphenylamine and monomer 3b indicate the importance of the electron-withdrawing groups on the pendent phenyl groups in determining the extent of delocalization of the extended multi-ring systems. Molecular orbital calculations suggest that the HOMO of 2b is delocalized about both anilino and thiophenyl portions of the molecule. Electronic supplementary material  Supplementary material is available for this article at and is accessible for authorized users.     

Nanomechanical characterization of one-step combustion-synthesized Al(4)B(2)O(9) and Al(18)B(4)O(33) nanowires

Two kinds of aluminum borate nanowires, Al(4)B(2)O(9) and Al(18)B(4)O(33), were successfully synthesized by a one-step combustion method through control of the Al:B atomic ratio and synthesis temperature. Both nanowires are single crystalline but have distinguishing growth habits. Nanoindentation tests were performed directly on individual nanowires to reveal their mechanical properties. A 70% reduction in elastic modulus was found in Al(18)B(4)O(33) nanowires compared with their bulk counterpart. Al(18)B(4)O(33) nanowires exhibited higher hardness and elastic modulus than Al(4)B(2)O(9) nanowires.     

Natural Passivity of Amorphous Fe_(40)Ni_(40)P_(14)B_6 and Fe_(54.6)Ni_(38)Si_(4.1)B_(2.3)V_1 Alloys

The natural passive films forrned on Fe_(40)Ni_(40)P_(14)B_6 and Fe_(54.6)Ni_(38)Si_(4.1)B_(2.3)V_1 amorphous alloys long-term exposed in air have been studied by X-ray photoelectron spectroscopy (XPS) and Auger electron (including Ar+ ion depth profiling) spectroscopy (AES). The following aspects have been investigated: (1) chemical states of the elements in the films. binding energies and the chemical shifts measured by XPSf (2) structure and composition of the films fand (3) thickness of the passive films determined by AES depth profiling and XPS analysis.     

TiCu_(0.5)Al_(0.5)Cr_(0.2)Ni_(0.1)高熵合金微观组织及性能研究

采用X射线衍射仪、光学显微镜、扫描电镜和透射电镜对TiCu_(0.5)Al_(0.5)Cr_(0.2)Ni_(0.1)高熵合金的相组成、相形貌、元素分布进行了系统研究,利用显微维氏硬度计测量了合金在室温下的硬度,通过电子万能试验机对合金进行了室温压缩试验,并在实验室模拟环境下进行合金防腐防污性能研究。结果表明:TiCu_(0.5)Al_(0.5)Cr_(0.2)Ni_(0.1)高熵合金主要由六方晶系Ti(CuAl)_2组成,大块状Ti(CuAl)_2相间存在条状组织,条状为AlCu_2Ti相,条间为CuTi_2相。树枝晶(DR)内Al元素和Cr元素含量较高,枝晶间(ID)Ti元素含量高于枝晶区域,而Ni元素和Cu元素整体分布较均匀。枝晶间(ID)显微硬度平均值为772HV,树枝晶DR显微硬度为690HV,枝晶间(ID)显微硬度高于树枝晶(DR)的;室温压缩强度为1 091 MPa。合金耐腐蚀性能良好,60℃人造海水中合金腐蚀失重量仅为-0.000 05 g,并具备一定的防污功能。     

Work Functions of Pd_(83.5)Si_(16.5)and Cu_(70)Ti_(30)Glassy Alloys

The work functions before and aftercrystallization of two glassy alloys,Pd_(83.5)Si_(16.5) andCu_(70)Ti_(30) have been measured by means of the con-tact potential difference method in the secondaryelectron field at room temperature under 10~(-5) Pavacuum.The results show that the work functionsof both glassy alloys are higher than those of thecorresponding crystalline alloys.     

非晶态半导体 As_(24)Se_(76)、As_(40)Se_(60)和 As_(50)Se_(50)的光量子效率研究

光量子效率是非晶态光电导材料的一个重要参数。本文利用静电放电的方法,探讨和研究了 As—Se 系统非晶态半导体材料的光量子效率与电场和组份的关系,得出的结果与 Onsager 理论描述的相一致。由分析而得到了等剂量组份、富 As 和富 Se 系统光量子效率的变化趋势。     

Review Properties of blends and composites based on poly(3-hydroxy)butyrate (PHB) and poly(3-hydroxybutyrate-hydroxyvalerate) (PHBV) copolymers

Poly(3-hydroxy)butyrate (PHB) and poly(3-hydroxybutyrate-hydroxyvalerate) (PHBV) copolymers are microbial polyesters presenting the advantages of biodegradability and biocompatibility over other thermoplastics with useful mechanical properties. However, their costs and performances must be adjusted by blending with suitable polymers. In this article the miscibility, morphology, mechanical behaviour and other prominent characteristics of a representative number of blends and composites of PHB and PHBV are summarized. In particular, blends with a few polyethers, polyesters, polyvinylacrylates and polysaccharides are illustrated. Furthermore, a brief paragraph deals with PHB/vegetal fiber composites. A wide range of properties emerges by blending with polymers having very different molecular structures and characteristics, such as crystallinity, glass transition and melting temperatures. The microstructure of the blends, resulting from thermodynamic and kinetic factors, is regarded as an important factor in controlling the mechanical and the biodegradation behaviours. Moreover, some considerations upon the nature of the driving force of the miscibility have been made in order to explain miscibility behaviour differences.     

Normal-incidence reflectance of crystalline K(6)C(60), Rb(6)C(60), and Cs(6)C(60)

The structure factors and normal-incidence reflectances of the alkali-metal-doped fulleride crystals M(6)C(60) (where M = K, Rb, or Cs) were calculated, and the peak reflectances are in the 2-20% range for incident wavelengths of 9-17 ?, which indicates that C(60) may be a promising transmissive (spacer) material for normal-incidence mirrors that have relatively high normal-incidence reflectance in the x-ray region.     

Fe73.5Ag1.0Nb3.0Si13.5B9.0软磁合金的结构和磁性

利用Ｘ射线衍射及磁测量等方法研究了不同退火温度下Ｆｅ７３．５Ａｇ１．０Ｎｂ３．０Ｓｉ１３．５Ｂ９．０软磁合金的结构和磁性，发现Ｆｅ７３．５Ａｇ１．０Ｎｂ３．０非晶态态合金在５００℃下退火处理１ｈ后，有少量的α－Ｆｅ和南Ａｇ析出，此时的软磁性能较好，随退火温度的增加，Ｆｅ２３Ｂ６、Ｆｅ２Ｂ、Ｆｅ３Ｂ等Ｆｅ－Ｂ化合物大量析出，软磁性能急剧下降，在Ｆｅ７３．５Ａｇ１．０Ｎｂ３．０Ｓｉ１３．５Ｂ９．０非晶     

Pb(II) and Cd(II) biosorption on Chondracanthus chamissoi (a red alga)

Chondracanthus chamissoi is an efficient biosorbent for Pb(II) and Cd(II). The sorption efficiency increases with pH and reaches an optimum around pH 4. Maximum sorption capacity reaches 1.37 mmol P bg(-1) and 0.76 mmol C dg(-1). The biosorbent has a marked preference for Pb(II) over Cd(II), though insufficient for separating these metals by a simple sorption step. The uptake kinetics is controlled by the resistance to intraparticle diffusion with a limited impact of particle size, metal concentration and sorbent dosage. In the present case, grinding the biomass does not improve sorption capacity and uptake kinetics. The sorption of metal ions is probably due to their interaction with carrageenan (one of the main constituents of the biosorbent): sulfonic groups (on the sulfated polysaccharide) have a higher affinity for Pb(II) than for Cd(II) according to HSAB rules.     

Sr0.7La0.15Ce0.15Fe11.7Zn0.3O19/PAn复合材料的制备及微波吸收性能

用溶胶-凝胶法制备了La、Ce、Zn掺杂锶铁氧体Sr0.7La0.15Ce0.15Fe11.7Zn0.3O19纳米粉晶,再通过原位聚合反应法制备了掺杂锶铁氧体/聚苯胺(PAn)复合材料.用XRD、SEM、FTIR对样品进行表征,用微波网络分析仪测量了样品在2～12.4GHz频率范围的微波反射率(R).研究结果表明,聚苯胺包覆于掺杂锶铁氧体粒子表面,Sr0.7La0.15Ce0.15Fe11.7Zn0.3O19/PAn微波吸收性能优良,具有磁损耗和电损耗协同作用.复合样品厚度为3mm时,10GHz频率位置吸收峰值为-28dB,10>dB吸收带宽为4.7GHz.从R随频率变化的曲线趋势看,最佳匹配厚度为2.6mm,吸收峰值接近-40dB,峰值频率高于12.4GHz,>10dB吸收带宽预计达到5.5GHz.