Crystal structure and hard magnetic properties of TbCu_7-type Sm_(0.98)Fe_(9.02–x)Ga_x nitrides

The compound Sm0.98Fe9.02–xGaxNδ(x=0, 0.25, 0.5, 0.75, 1) were prepared by melt-spun method and subsequent annealing and nitriding. The Rietveld analysis showed that the lattice expansion played an important role in improving the Curie temperature. An obvious development of the Curie temperature was obtained with the increased Ga content from x=0–1(ΔTc=90 oC). The optimum coercivity of nitrides was obtained at x=0.25 with the value Hcj=652 kA/m(8.15 kOe) after annealing, which corresponded to a reasonable distribution of grain sizes of both TbCu7-type SmFe9Nδ and α-Fe. However, an excess of Ga doping might lead to an abnormal growth of α-Fe, which in turn deteriorated the magnetic properties. It was concluded that a moderate Ga content was very effective in raising the coercivity and Curie temperament in the TbCu7-type Sm-Fe-N.     

洋葱酱罐头褐变、变甜的机理及其控制研究

探讨了用白皮洋葱加工洋葱酱过程中产品发生褐变及辛辣风味减弱变甜的机理，并根据洋葱酱加工工艺的特点，研究制定了防止褐变及保持洋葱典型风味的控制方法。     

21世纪中国磁体产业展望

2000年中国烧结与粘结NdFeB磁体的总产量为6950吨,年增长率超过40%。中国稀土磁体产业的进展不仅表现在量的方面,也表现在质的方面,诸如1：12型、3：29型等新金属间化合物的开发;在工艺方面,用直接压制成型的“一步成型工艺”取代传统的“两步成型工艺”（预成型 等静压）取得成功。某些中国磁体厂家已成功应用“一步成型工艺”制备瓦形和异形磁体。此外,在不久的将来,中国生产的速凝薄片将被普遍采用,以取代传统的铸造合金作为烧结磁体的原料,总之,中国磁体产业在21世纪将能向全球用户提供价廉而优质的稀土磁体。     

开菲尔粒及其发酵液中菌相分析

为了研制开菲尔发酵剂，本试验测定了开菲尔粒及其发酵液中几种主要微生物的数量。两者结果均表明其中乳酸菌多于醋酸菌，醋酸菌多于酵母菌，而且乳酸菌类中大多数为兼性厌氧菌。     

Phase and microstructure of TbCuT-type SmFe melt-spun powders

The SmxZr0.3Fe9.1-xCo0.6(x=0.8,0.9,1.0) powders were prepared by melt-spun method with different quenching velocities.The phase and microstructure were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The Th2Zn17-type structure of the as-cast state changed to TbCu7-type after quenching to a rotating molybdenum roll under certain velocity,and the formation of TbCu7-type phase was strictly depending on the Sm content and roll speed.The SEM morphology showed that the Fe-rich zone was typically fish-bone structure and TEM diffraction pattern indicated the nano-scale crystal size with TbCu7-structure when x=0.9,and FCC type γ-Fe on the basis of α-Fe formed in the non-equilibrium solidification could be detected by selected area electron diffraction(SAED) indexing in the x=0.8 samples.     

全自动升降书桌设计与分析

根据对日常生活的观察和对便携式书桌的研究，提出并设计了一种在家庭、办公中都能用到的新型自动升降式书桌。桌面通过轴承连接使其能够在垂直方向上进行90。转动，其通过底部电机的转动带动丝杆的转动，将旋转运动转换成直线运动，从而驱动桌面的垂直升降。绘制了sohdworks三维立体图模型，并进行了动力学仿真。进行实验室样机试验，其结果验证了结构设计的合理性。     

Fe含量对快淬SmFe合金结构的影响

在轮速为40 m·s-1快淬制备不同Fe含量的亚稳态快淬SmFe x(x=7.5,8.0,8.5,9.0,9.5,10.0,10.5,11.0,12.0,13.0)合金,经过800℃退火处理60 min,采用XRD分析了快淬SmFe x合金退火前后的相组成和晶体结构,并结合Rietveld结构精修方法分析了TbCu7型SmFe9相的晶体结构。结果表明:快淬SmFe x合金在化学计量数SmFe x(x=7.5~8.0)时,形成Th2Zn17型Sm2Fe17和少量的SmFe2;随着Fe含量增加,在x=8.5~13.0时,由平衡相转变成亚稳TbCu7型SmFe9相,α-Fe含量逐渐增多。随着Fe含量增加,SmFe合金的晶格常数a不断减小,而晶格常数c,c/a不断增大。在TbCu7型SmFe9相中Fe原子分别位于2e,3g,6l晶位,Sm原子自由占据1a晶位。2e晶位哑铃状Fe-Fe原子对的的占位趋于无序。退火后SmFe x合金在化学计量数x=8.5,9.0时,由亚稳相TbCu7型SmFe9转变为平衡Th2Zn17型Sm2Fe17相;在化学计量数SmFe x(x=9.5~13.0)时,保持TbCu7型SmFe9不变。退火使2e晶位哑铃状Fe-Fe原子对有序排列,Sm原子在1a晶位的占位率提高,晶体结构由TbCu7型结构转变成Th2Zn17型结构,但Fe含量超过一定值后,无法继续这种转变。退火SmFe x合金晶体结构的晶胞参数变化规律与淬火态相同,退火SmFe合金中α-Fe含量增多。     

Sm2Fe17Nx型稀土永磁材料的制备与性能

研究SmFeN稀土永磁材料球磨法制备过程和材料性能.Sm-Fe母合金合适的Sm补偿量为20%,氮化前最佳的球磨时间为为1.5h,合金氮化后为各向同性的粗磁粉,经过进一步球磨细化后,可以得到各向异性的性能高的磁粉.     

经济型闭环数控系统的插补方法

在改进时间分割法的基础上,对经济型闭环数控系统提出了一种适合的插补方法。该插补方法具有效率高,算法简单,容易实现多轴联动,并可以插补各种复杂曲线轮廓的特点,因而能充分发挥数控系统的效能。