亚铁离子抗低氧作用的初步研究

【目的】为了研究亚铁离子的抗低氧作用及其可能假说机制.【方法】以硫酸亚铁片为试验材料,对小鼠连续灌胃给药10d,分别进行常压密闭缺氧试验,测定血常规,肌肉和心肌肌红蛋白含量以及肝、血液、脾和心脏铁元素含量.【结果】硫酸亚铁低、高剂量组均可以显著延长小鼠的大喘时间和死亡时间,提高小鼠的血红蛋白的含量、红细胞数,增加肌肉和心肌中的肌红蛋白的含量,其中,心肌中的肌红蛋白与对照间具有显著性差异;肝、心脏中的铁元素含量显著增加,而血液和脾中铁元素含量的差异性不显著.【结论】亚铁离子抗低氧作用机制可能与机体中血红蛋白,红细抱,肌红蛋白等含铁物质的增加有关.     

“复方生血灵”中硫酸亚铁在比利时兔体内代谢动力学的研究

“复方生血灵”中硫酸亚铁在兔体内药代动力学结果,给药后0.5h血中Fe~(++)的含量为37.4280+11.4637μg/ml;Tmax为3.7398±1.1911h;Cmax为53.7259±13.4949μg/ml;Ka为0.4123±0.0698h~(-1)t1/2Ka为1.7491±0.2023h;t1/2Ke为4.5718±1.2084h;Va为0.8325±0.0963L/kg。经X~2检验P>0.05,实测值与理论值差异不显著,拟合度较高。     

壳聚糖亚铁配合物的制备

【目的】探讨壳聚糖与亚铁络合制备壳聚糖亚铁配合物的最佳条件,为壳聚糖亚铁配合物在降低卷烟主流烟气中CO的应用研究提供理论依据。【方法】研究不同制备条件（Fe^2＋初始浓度、体系pH、络合时间、壳聚糖用量）对壳聚糖亚铁配合物生成量的影响,寻求最佳制备条件。【结果】当Fe^2＋的浓度15．0mg／mL,体系pH2．5-3．0,搅拌1.0h,静置反应4．0h,壳聚糖用量0．1g时,壳聚糖对Fe^2＋的吸附量最大,可达523mg／g。【结论】将壳聚糖与亚铁络合制备成壳聚糖亚铁配合物应用在卷烟滤嘴上可降低卷烟主流烟气中CO含量。     

Order-disorder transition in polycrystalline c60 films

High-resolution Raman spectroscopy of polycrystalline films of C(60) deposited under ultrahigh-vacuum conditions show that the spectrum below 244 +/- 3 kelvin consists of a superposition of two components whose relative contributions are temperature-dependent. The spectrum of the more intense of the two components is similar to that obtained for air- or oxygen-exposed samples of C(60) at room temperature, whereas the spectrum above 244 +/- 3 kelvin corresponds to one previously reported for oxygen-free samples of C(60). The results may indicate an order-disorder phase transition involving the percolation of a cluster of C(60) molecules engaged in coherent Raman scattering.     

Carbonado: natural polycrystalline diamond

Carbonados are porous aggregates of mostly xenomorphic diamond crystallites ranging in diameter from a fraction of a micron to over 20 microns. Crystalline inclusions (up to 3 percent) occur in the pores of the crystallites and consist mainly of orthoclase and small amounts of other igneous, metamorphic, and secondary minerals.     

不同氨基酸螯合铁及补铁方案对仔猪生长发育的调控效应

选用临产前一个月的第2胎纯种杜洛克母猪17头,研究赖氨酸铁和甘氨酸铁作为母、仔猪日粮铁源添加剂对仔猪生长发育的影响.结果表明,母、仔猪分别采食以赖氨酸铁和甘氨酸铁为铁源的日粮,仔猪出生后即使不注射铁补针也可获得与常规补铁同样的生长发育效果;若同时辅以铁补针,则仔猪的生长速度可显著提高(P<0.05).不同补铁方式对仔猪生长发育的效应分析显示,铁源和铁补针能显著影响仔猪的日增重(P<0.05),且对提高仔猪0～35 d日增重有显著的互作效应(P<0.05).就补铁方式而言,赖氨酸铁辅以注射铁补针是规模猪场较为理想的仔猪补铁方式.     

Remobilization in the cratonic lithosphere recorded in polycrystalline diamond

Polycrystalline diamonds (framesites) from the Venetia kimberlite in South Africa contain silicate minerals whose isotopic and trace element characteristics document remobilization of older carbon and silicate components to form the framesites shortly before kimberlite eruption. Chemical variations within the garnets correlate with carbon isotopes in the diamonds, indicating contemporaneous formation. Trace element, radiogenic, and stable isotope variations can be explained by the interaction of eclogites with a carbonatitic melt, derived by remobilization of material that had been stored for a considerable time in the lithosphere. These results indicate more recent formation of diamonds from older materials within the cratonic lithosphere.     

Single-crystal-like diffraction data from polycrystalline materials

A method for solving structures from powder diffraction data was developed, and its validity was demonstrated on three complex structures. The method uses a textured sample and exploits the high intensity and parallel nature of synchrotron radiation. In principle, crystal structures as complex as those routinely solved by single-crystal methods can be determined with this approach. For example, the as-synthesized form of the zeolite UTD-1, with 69 nonhydrogen atoms in the asymmetric unit, could be solved directly. With this method, a larger range of structural complexity becomes accessible to scientists interested in the structures of polycrystalline materials that cannot be grown as single crystals.     

Tailoring electrical transport across grain boundaries in polycrystalline graphene

Graphene produced by chemical vapor deposition (CVD) is polycrystalline, and scattering of charge carriers at grain boundaries (GBs) could degrade its performance relative to exfoliated, single-crystal graphene. However, the electrical properties of GBs have so far been addressed indirectly without simultaneous knowledge of their locations and structures. We present electrical measurements on individual GBs in CVD graphene first imaged by transmission electron microscopy. Unexpectedly, the electrical conductance improves by one order of magnitude for GBs with better interdomain connectivity. Our study suggests that polycrystalline graphene with good stitching may allow for uniformly high electrical performance rivaling that of exfoliated samples, which we demonstrate using optimized growth conditions and device geometry.     

过氧化物酶在水稻亚铁毒害中的作用

根据溶液培养试验从Ａｚｕｃｅｎａ×ＩＲ６４的ＤＨ群体中选出对铁毒抗性、敏感品系各５个，研究不同基因型水稻过氧化物酶（ＰＯＤ）活性与其对铁毒抗性的关系．试验结果表明：各品系叶片ＰＯＤ活性与其对铁毒耐受能力具有正相关性，抗性品系的ＰＯＤ活性高于敏感品系；抗性和敏感品系ＰＯＤ活性诱导程度与铁吸收量分别表现正相关和负相关．说明ＰＯＤ在水稻抗铁毒中起着重要的作用     

Synthesis of polycrystalline chalcopyrite semiconductors by microwave irradiation

Polycrystalline samples of the chalcopyrites CulnS(2), CulnSe(2), and CulnSSe were Prepared from stoichiometric mixtures of the pure elements by microwave irradiation. The reactions were performed in sealed quartz tubes in as few as 3 minutes. The products were analyzed by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray analysis, and x-ray photoelectron spectroscopy. The surface morphology and shape of the particles produced by this method suggest that the products are formed from liquid melts. This method could be applied to the production of bulk chalcopyrite as sources for thin film growth.     

Echinoderm calcite: single crystal or polycrystalline aggregate

Electron microscopy of natural and broken surfaces of echinoid skeletal plates reveals that the interior portions have the morphology of a single crystal, whereas the exterior is a polycrystalline aggregate with preferred orientation. These data help to resolve earlier contradictory x-ray and optical evidence.     

Cobalt-base high-temperature alloys

We have identified cobalt-base superalloys showing a high-temperature strength greater than those of conventional nickel-base superalloys. The cobalt-base alloys are strengthened by a ternary compound with the L1(2) structure, gamma' Co3(Al,W), which precipitates in the disordered gamma face-centered cubic cobalt matrix with high coherency and with high melting points. We also identified a ternary compound, gamma' Ir3(Al,W), with the L1(2) structure, which suggests that the Co-Ir-Al-W-base systems with gamma+gamma' (Co,Ir)3(Al,W) structures offer great promise as candidates for next-generation high-temperature materials.     

New magnetic alloys

Three notable new developments in magnetic alloys are highlighted. These include rare earth-cobalt permanent magnets with maximum energy products up to 240 kilojoules per cubic meter; chromium-cobalt-iron permanent magnets that have magnetic properties similar to those of the Alnicos, but contain only about half as much cobalt and are sufficiently ductile to be cold-formable; and high-induction grain-oriented silicon steels that exhibit 20 percent less core loss as transformer core materials than conventional oriented grades.     

Transient interface sharpening in miscible alloys

We observed that diffuse interfaces sharpen rather than broaden in completely miscible ideal binary systems. This is shown in situ during heat treatments at gradually increasing temperatures by scattering of synchrotron radiation in coherent Mo/V multilayers containing initially diffuse interfaces. This effect provides a useful tool for the improvement of interfaces and offers a way to fabricate better x-ray or neutron mirrors, microelectronic devices, or multilayers with giant magnetic resistance.     

Oxidation of ferrous iron in vermiculite and biotite alters fixation and replaceability of potassium

Oxidation of octahedral ferrous to ferric iron in soil vermiculite clays and biotites increases the potassium-fixation capacity of vermiculites and increases the difficulty of replacing interlayer potassium in biotites. This unexpected effect is believed to be related to an increase in the attractive forces between potassium ions and oxygen ions of the surface layers which is brought about by a tilting of the dipole of the octahedral hydroxyl ions from a perpendicular position to an inclined position with respect to the cleavage plane.     

不同铁源对母猪乳铁含量和仔猪血液学参数的影响

17头胎次为第2胎的纯种杜洛克母猪，按3种铁源（赖氨酸铁、甘氨酸铁和硫酸亚铁）和一个水平（按铁计，母猪饲料中添加量120mg/kg；仔猪饲料中添加量150mg/kg），随机分为3个处理，以硫酸亚铁为对照，测定母猪产后不同阶段的母乳铁含量，在乳猪不注射铁补针的条件下，测定不同日龄的乳猪血红蛋白、血清铁和血清总铁结合力等指标，研究了不同铁源对母猪乳铁含量和仔猪血液学参数的影响，结果表明：赖氨酸铁显著影响母乳铁含量（P＜0．05）；2种氨基酸螯合铁组都在不同程度促进仔猪血红蛋白的提高，赖氨酸铁显著提高血红蛋白水平（P＜0．05），赖氨酸铁显著降低14-35日龄仔猪血清总铁结合力（P＜0．05）。     

Disorder in Al-li-cu and Al-mn-si icosahedral alloys

Faceted dendrites of icosahedral AL(6)Li(3)Cu have been studied by high-resolution x-ray scattering. The samples display long-range icosahedral symmetry both in their diffraction patterns and in their macroscopic morphology. Despite the appearance of well-defined facets, the samples have a high degree of atomic disorder. The Bragg peaks have symmetry-dependent shapes and widths that scale linearly with G perpendicular (phason momentum). The peak widths are surprisingly similar to those found in icosahedral Al-Mn-Si alloys in both their absolute magnitude and their dependence on G perpendicular. The origin of these features in models for the icosahedral phase is discussed.     

Ductile ordered intermetallic alloys

Many ordered intermetallic alloys have attractive high-temperature properties; however, low ductility and brittle fracture limit their use for structural applications. The embrittlement in these alloys is mainly caused by an insufficient number of slip systems (bulk brittleness) and poor grain-boundary cohesion. Recent studies have shown that the ductility and fabricability of ordered intermetallics can be substantially improved by alloying processes and control of microstructural features through rapid solidification and thermomechanical treatments. These results demonstrate that the brittleness problem associated with ordered intermetallics can be overcome by using physical metallurgical principles. Application of these principles will be illustrated by results on Ni(3)Al and Ni(3)V-Co(3)V-Fe(3)V. The potential for developing these alloys as a new class of high-temperature structural materials is discussed.     

Ductile superconducting copper-base alloys

A new class of ductile superconductors has been prepared by casting and appropriate heat treatments. These alloys superconduct between 4 degrees and 18 degrees K and contain at least 90 atom percent copper and a superconducting phase such as Nb(3)Sn or niobium. They can be processed into wires by conventional metallurgical techniques.