无机功能材料的结构、性能与化学键性质关系研究

本文使用复杂晶体化学键理论研究了无机功能材料的电子结构、性能与化学键参数之间的关系。具体的研究对象包括铜氧化物高温超导体、A格位和B格位掺杂ABO＿3型化合物以及镧碳团簇的结构、稳定性与振动光谱等问题。结果表明，对于Y123、Y124、Y247结构的高温超导体，发现当铜氧面的共价性小于铜氧链的共价性时，应该有超导现象产生，解释了在Y_(1-X)Pr_xBa_2Cu_3O_7中在Pr的掺杂浓度大于0.55时超导现象消失这一实验事实。而在其它系列高温超导体中没有发现此规律。据此我们预测在Y_(1-x)Pr_xBa_2Cu_3O_7中，只要Pr的价态小于3．15价，则不论Pr的浓度为多少超导现象永远不会消失：若Pr的价态完全为4.0价，则超导现象会在Pr的浓度大于0.19时消失。在Y_(1-x)Ca_xBa_2Cu_3O_(6+y)中，铜氧面上的载流子浓度是氧含量和Ca掺杂量相互竞争的结果。由Ca掺杂产生的载流子有一部分被束缚在了氧的周围，使得可流动的载流子的数目并未增加，甚至可能减小，从而导致超导温度下降。在对Tl系和Hg系的研究中，发现对于最高的超导温度有一个最佳的载流子浓度值，载流子浓度过高或过低均对超导不利。此外我们还发现对铜氧化物超导体，氧含量的变化既影响CuO链又影响CuO_2面内Cu-O键的共价性，而掺杂的阳离子的浓度只影响CuO_2面内键的共价性。以上这些结果说明本文尚未发现与超导有关的统一规律，同时也说明产生超导的原因是复杂的，还有待于进一步研究。对于ABO＿3型化合物，结构相变化使得化学键参数产生突变。对于镧碳团簇，发现在碳的个数小于10时，碳的个数为偶数时稀土位于碳环上时最稳定，碳的个数为奇数时稀土通过两个单键与碳环相连最稳定。

Study of physicochemical properties and active oxygen in structures of layered mixed La4BaCu5-xMxO13+lambda (M = Mn, Co)

Two series of layered mixed oxides La4BaCu5-xMxO13+lambda(M = Mn, Co, x = 0 similar to 5) were prepared and characterized by means of XRD, XPS, O-2-TPD and chemical analysis. The results show that their structures are 5-layered ABO(3) perovskite, and the XPS and O-2-TPD investigation confirms that there exists synergistic effect between Cu ion and M when M ion is doped into the lattice of La4BaCu5O13+lambda,, and the synergistic effect between Mn and Cu is stronger than that of Cu-Co.

Synthesis, characterization and catalytic behavior of layered mixed oxides La4BaCu5-xMnxO12 in NO reduction by CO

A series of sample having the stoichiometry La4BaCu5-xMnxO12 (x = 0 similar to 5) were prepared, characterized by XRD, IR and H-2 - TPR and used as catalyst for NO + CO reaction. It was found that they have 5 - layered ABO(3) - type structure. The results of H-2 - TPR showed that the Cu ion was more easily reduced while a part of them was replaced by Mn ions. Their catalytic behavior to NO + CO reaction was investigate, La4BaCu2Mn3O12 showed the highest catalyst activity for the reaction than the others. The reaction mechanism is discussed:the activity of the catalysts could be attributed to the Cu ions, but it was improved when Mn ions took the place of some Cu ions.

Layered La-Ba-Cu mixed oxides with perovskite structure as catalyst for NO reduction by CO

The mixed oxides, including LaBa2Cu3O7, LaBaCu2O5, La4BaCu5O12 with perovskite structure, were prepared. The catalysts were characterized by means of chemical analysis, XRD, H-2-TPR. It was found that their structures were layered ABO(3) perovskite structure and they were the active catalysts for the NO reduction by CO. The existence of Cu3+ is an important factor to give the catalysts a high activity for the NO reduction by CO.

Crystal field splitting of Nd3+ ion and chemical bonds on the host crystals

In terms of the theory of chemical bonds on complex crystals(CBCC), the crystal structure and coordination, the chemical bond parameters of a group of ABO(4)-type crystals were calculated in detail, The results show that the relation between the crystal field splitting of Nd3+ ion and the covalency of the crystal is linear.

Y-Ba-Cu-O mixed oxides for production of diphenols in liquid-solid phase

Superconductor mixed oxides were often used as catalysts at higher temperature in gas phase oxidations, and considered not suitable for lower temperature reactions in the liquid-solid phase; here the catalysis of YBa2Cu3O7+/-x and Y2BaCuO5+/-x in the phenol hydroxylation at lower temperature with H2O2 as oxygen donor was studied, and found that the superconductor YBa2Cu3O7+/-x, has no catalytic activity for phenol hydroxylation, but Y2BaCuO5+/-x does, even has better catalytic activity and stability than most previously reported ones. With the studies of catalysis of other simple metal oxides and perovskite-like mixed oxides, a radical substitution mechanism is proposed and the experimental facts are explained clearly, and draw a conclusion that the perovskite-like mixed oxides with (AO)(ABO(3)) and (AO)2(ABO(3)) structure have better catalytic activity than the simple perovskite oxides with (ABO(3))(3) structure alone, and (AO) structure unit is the key for the mixed oxides to have the phenol hydroxylation activity. No pollution of this process is very important for its further industrial application.

STUDIES ON SYNTHESIS, CHARACTERIZATION AND CATALYTIC PROPERTIES OF LAN+1NINO3N+1 MIXED OXIDES

A series of (AO) (ABO(3))(n)(A = La, B = Ni, n = 1 similar to 4) type mixed oxides were synthesized and characterized by means of XRD, XPS, IR, TPD, TPR. Their structure characteristics and redox properties were studied. The nonstoichiometry (lambda) of oxygen and the valence of transition metal Ni were determined by using chemical analysis method. The catalytic activities of this series of mixed oxides for complete oxidation of CO and CH4 were examined and the relationships among activity, composition and structure were discussed.

X-Ray Photoelectron Spectroscopy Study of LaMn1-xFexO3 (x=0-1) Oxides

The redox potential, surface composition and oxygen species of a series of complex oxides LaMn1-xFexO3 (x=0-1) having perovskite structure (ABO(3)) have been investigated by means of XI'S. The variation of binding energies referring to Mn2p and Fe 2p under different treatment offerred an obvious evidence of redox between Mn and Fe, which could be expressed as Mn4+ + Fe(3-delta)+ Mn(4-delta)+ Fe3+ Feat Through computer fit three kinds of adsorbed oxygen species (O-I, O-II, O-III) have been evaluated based on the XPS spectra of O1s. From the variation of contents of different oxygen species, it could be concluded that. the redox occuring in the surface might be related with the adsorbed oxygen species O-I and O-II, furthermore the possibility of transfer of electron between adsorption site and oxygen was also discussed.

XPS Study of the Oxygen State in LaMnyCo1-yO3 Catalysts

A series of LaMnyCo1-yO3 compounds were prepared by the complexation method with citric acid. XPS was used to investigate the oxygen state in perovskite-type (ABO(3)) Complex oxide LaMnyCo1-yO3 catalysts. The result showed that three oxygen species (alpha

Uto­pia języka dosko­na­łego w euro­pej­skim kręgu kul­tu­ro­wym

Homo sapiens, gatu­nek nie­mal pod każ­dym wzglę­dem jed­no­rodny fizjo­lo­gicz­nie, pod­dany pra­wie jed­na­ko­wym pro­ce­som bio­lo­gicz­nym i spo­łecz­nym, o podob­nej ewo­lu­cyj­nej prze­szło­ści; gatu­nek, który poro­zu­miewa się tysią­cami róż­nych języ­ków. Ludzie są iden­tycz­nie zbu­do­wani, ale nie posłu­gują się jedną, uni­wer­salną mową. Korzy­ści, jakie wyni­ka­łyby ze wspól­nego, zro­zu­mia­łego dla każ­dego czło­wieka języka, są oczywiste. Tęsk­nota za takim języ­kiem jest obecna we wszyst­kich cywi­li­za­cjach. Wątek pomie­sza­nia języ­ków (The Con­fu­sion of Ton­gues), rekon­struk­cja i kon­struk­cja języka dosko­na­łego snuje się przez wszyst­kie kul­tury. W mito­lo­gii wie­lość języ­ków to nie­szczę­ście i sła­bość ludz­ko­ści. Sta­ro­żytni Per­so­wie wie­rzyli, iż wie­lo­ję­zyczny ród czło­wie­czy doczeka się w końcu wspól­nego języka w kró­le­stwie Ormuz­do­wym.

Twierdzenia o punktach stałych pewnych klas operatorów nieliniowych wraz z ich zastosowaniami

Wydział Matematyki i Informatyki

Problemy strefy Euro

Oficjalne kredyty ratunkowe dla niektórych krajów w strefie euro nie mogą zastąpić tam reform, które – poprawiając sytuację gospodarczą – pozwolą odzyskać owym krajom zaufanie rynków finansowych. W literaturze wymienia się dwie główne strukturalne słabości wspólnej waluty (euro): 1. Jednolita polityka pieniądza nie jest w stanie uwzględnić odmienności sytuacji poszczególnych krajów, a wspólny pieniądz nie pozwala na dewaluację w obrębie strefy euro; 2. Strefa euro istnieje bez „unii politycznej”. Artykuł analizuje zasadność tych tez.

Interleukin-15 receptor blockade in non-human primate kidney transplantation.

BACKGROUND: Interleukin (IL)-15 is a chemotactic factor to T cells. It induces proliferation and promotes survival of activated T cells. IL-15 receptor blockade in mouse cardiac and islet allotransplant models has led to long-term engraftment and a regulatory T-cell environment. This study investigated the efficacy of IL-15 receptor blockade using Mut-IL-15/Fc in an outbred non-human primate model of renal allotransplantation. METHODS: Male cynomolgus macaque donor-recipient pairs were selected based on ABO typing, major histocompatibility complex class I typing, and carboxy-fluorescein diacetate succinimidyl ester-based mixed lymphocyte responses. Once animals were assigned to one of six treatment groups, they underwent renal transplantation and bilateral native nephrectomy. Serum creatinine level was monitored twice weekly and as indicated, and protocol biopsies were performed. Rejection was defined as a increase in serum creatinine to 1.5 mg/dL or higher and was confirmed histologically. Complete blood counts and flow cytometric analyses were performed periodically posttransplant; pharmacokinetic parameters of Mut-IL-15/Fc were assessed. RESULTS: Compared with control animals, Mut-IL-15/Fc-treated animals did not demonstrate increased graft survival despite adequate serum levels of Mut-IL-15/Fc. Flow cytometric analysis of white blood cell subgroups demonstrated a decrease in CD8 T-cell and natural killer cell numbers, although this did not reach statistical significance. Interestingly, two animals receiving Mut-IL-15/Fc developed infectious complications, but no infection was seen in control animals. Renal pathology varied widely. CONCLUSIONS: Peritransplant IL-15 receptor blockade does not prolong allograft survival in non-human primate renal transplantation; however, it reduces the number of CD8 T cells and natural killer cells in the peripheral blood.

Lewis phenotype, secretor status, and coeliac disease

Patients who cannot secrete ABO and Lewis blood group antigens into body fluids, an ability controlled by a single gene on chromosome 19, are known to be at increased risk of certain autoimmune diseases associated with human leucocyte antigen (HLA) markers. This study investigated the possibility of an association with coeliac disease using red cell Lewis (Le) blood group phenotype to infer secretor status. Among 73 patients with coeliac disease who had Le a or b antigen, 48% were non-secretors (Le a + b-) compared with 27% of 137 blood donors (p = 0.004: odds ratio 2.49, 95% confidence intervals 1.37 to 4.51) and 26% of 62 medical and nursing staff controls (p = 0.014: odds ratio 2.65, 95% confidence intervals 1.27 to 5.50). Clinical characteristics did not differ between secretors and non-secretors with coeliac disease. Thus, the non-secretor state is significantly associated with coeliac disease, suggesting that genes on chromosome 19 may directly or indirectly participate in conferring susceptibility.

Secretor status and Helicobacter pylori infection are independent risk factors for gastroduodenal disease

The hypothesis that non-secretors of ABO blood group antigens, a group shown to be more susceptible to certain bacterial infections, may be at greater risk of gastroduodenal disease because of increased susceptibility to Helicobacter pylori infection was investigated. Of 101 patients with symptoms of dyspepsia who were undergoing endoscopy, 32% were non-secretors (determined from Lewis blood group phenotype), 36% had endoscopically visible gastroduodenal disease (antral gastritis, gastric ulcer, erosive duodenitis, duodenal ulcer or some combination), and 58% had H pylori detected in antral biopsy specimens. Non-secretors and patients with H pylori infection were significantly more likely to have gastroduodenal disease (p = 0.02 and p = 0.002 respectively). There was, however, no significant association between secretor status and H pylori infection, logistic regression analysis confirming that these were independently associated with gastroduodenal disease. Overall, the relative risk of gastroduodenal disease for non-secretors compared with secretors was 1.9 (95% confidence intervals 1.2, 3.2). Non-secretion of ABO blood group antigens is not related to H pylori infection but is independently and significantly associated with endoscopic gastroduodenal disease. The mechanism of this remains to be explained.