88 resultados para årskurs 2-5


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采用离心机法,研究聚丙烯酸钠与聚丙烯酰胺2种高分子化合物在5种使用浓度(占干土质量0、0.01%、0.08%、0.2%与1%)的条件下对3种土壤(砂土、壤土、黏土)持水能力的影响。结果表明:3种土壤在0.01~1.5MPa水吸力时,持水能力随着2种高分子材料用量的增加而增加,砂土的作用效果较壤土、黏土更显著;2种高分子材料与土壤质量比控制在8/10000~2/1000范围内其作用效果较好,该用量条件下高分子吸持水分平均可释放83.7%供植物吸收利用。2种高分子材料对土壤持水能力的作用效果基本相同。

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建立了污染土壤预制床处理工程 ,对不同类型原油污染土壤分别进行堆腐处理 ,历时 2个阶段 ,共运行2 1 0d .当稀油、稠油、特稠油和高凝油污染土壤中石油烃总量 (TPH)为 2 5 8~ 77 2 g·kg- 1时 ,经过 5 3d(为第 1阶段 )的运行 ,TPH去除率 3 8 3 7%~ 5 6 74 % .第 2年 (为第 2阶段 )继续处理 1 5 6d ,TPH降解率达到 66 5 9%~80 96% .连续运行结果表明 ,污染土壤中易分解的石油烃污染物大部分在第 1阶段得到降解 ,第二阶段降解率明显降低

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一、 药物滥用是一种慢性、复发性脑疾病。药物滥用将导致药物成瘾(addiction),其主要表现有药物依赖、药物耐受、药物敏感化以及药物停用后的戒断症状(withdraw symptom)。药物成瘾的核心特征是强迫性觅药和用药行为。药物成瘾会导致药物滥用者认知功能的损伤和认知偏差,并会造成滥用者情绪异常。药物成瘾是一个复杂的生物学过程,有着及其复杂的机理。对药物成瘾机制的解释有很多种,主要认为成瘾过程是一种学习记忆过程,学习记忆的机制在药物成瘾过程中起到了非常重要的作用。首先,学习记忆和药物成瘾过程都受到了相似的神经营养因子以及神经递质系统的调控,例如:它们都受cAMP,CREB等调控因子的调控。其次,研究发现与成瘾相关的线索,如用药有关的人物、地点或暗示等,在药物戒断很长时间后都会恢复吸毒者的用药行为。并且,当把与成瘾相关的线索呈现给毒品戒断中的人时,这些人会出现心率、呼吸加快,血压升高等现象,甚至表现出明显的渴求行为。药物对学习记忆的影响是复杂的,虽然重复使用药物会导致药物成瘾,并且这个过程需要学习记忆机制的参与,但同时使用吗啡却会对其他类型的学习记忆(如:恐惧性学习记忆、一次性被动回避学习记忆和水迷宫空间学习记忆)造成破坏。学习前给予吗啡可以剂量及状态依赖地破坏被动回避试验以及空间辨别试验的记忆获取过程。学习过程结束后立即给予吗啡可以破坏一次性被动回避试验、主动回避试验和恐惧条件化试验的记忆巩固过程。测试前给予吗啡可以破坏空间辨别试验的记忆提取过程。本研究的目的在于更进一步地了解使用吗啡导致吗啡成瘾以及使用吗啡导致学习记忆的各个阶段受损的机制。为此我们采用了药理学以及多种行为学的方法,1、用PTZ诱发的癫痫持续状态干扰吗啡成瘾的学习记忆过程,进一步比较了吗啡成瘾的学习记忆与其他学习记忆,例如:空间学习记忆以及食物奖赏学习记忆的机制有何异同;2、研究了β-肾上腺素系统与阿片系统在空间记忆巩固过程中的相互作用;3、我们还研究了NMDA受体的激动剂和拮抗剂在吗啡破坏空间记忆提取过程中的作用。研究结果发现: 1.戊四唑诱发的癫痫持续状态,对吗啡建立的条件化位置偏好没有任何影响,动物仍然对阳性箱(吗啡匹配箱)表现出明显的偏好。但是癫痫持续状态破坏了食物建立的条件化位置偏好,并且还破坏了水迷宫和Y迷宫检测的空间记忆。癫痫持续状态破坏了食物建立的条件化位置偏好,原因不是由于其影响了动物的食欲。此外,癫痫持续状态也没有持续地破坏动物的活动能力,因此,对动物活动量的影响也不是造成其他学习记忆破坏的原因。这些结果说明,吗啡成瘾的学习记忆和普通的学习记忆在机制上可能存在不同之处。为了说明这个问题,我们还需要进行其他更深入的研究。 2、训练后立即单独注射吗啡(0.25和2.5 mg/kg)或心得安(2,10和20 mg/kg)都不会破坏动物Y-迷宫空间记忆的巩固过程,动物仍然能识别新异环境,并在里面停留较长时间。但是,训练后同时注射吗啡和心得安却可以破坏动物空间记忆的巩固过程。并且,较高剂量的吗啡(2.5 mg/kg)加上较高剂量的心得安(10和20 mg/kg)对记忆的破坏更严重,实验组动物在新异环境停留的时间显著低于对照组。这说明阿片系统和去甲肾上腺素系统在破坏记忆巩固的过程中可能有协同作用。 3、记忆提取前30分钟注射吗啡(1和10 mg/kg)可以剂量依赖地破坏Y-迷宫空间记忆的提取。单独注射NMDA受体的激动剂NMDA(1,2和4 mg/kg)对动物的空间记忆提取没有影响,但是,单独注射NMDA受体拮抗剂MK-801(0.05,0.1和0.2 mg/kg)剂量依赖地破坏了空间记忆的提取。同时注射吗啡(10 mg/kg)和NMDA(2 mg/kg)可以阻断吗啡对空间记忆造成的破坏作用。相反,共同注射吗啡(1 mg/kg)和MK-801(0.05 mg/kg)可以加重吗啡对空间记忆造成的破坏作用。这说明谷氨酸系统可以干扰吗啡对记忆提取过程的影响。 二、衰老严重地影响了人们的视觉功能,然而眼睛光学系统的老年性改变并不能完全解释清楚这种视觉功能衰退。一般认为是神经系统的退化导致了这种老年性功能降低。但是,研究显示视网膜(retina)和外膝体(dorsal lateral geniculate nucleus, dLGN)在衰老的过程中神经元的数量和体积以及神经元的功能特性,如对比度敏感性、空间分辨率等,都没有明显的变化,因此,人们推测老化导致的神经系统的变化发生在更高级的视觉皮层。过去几年的研究发现老年动物视觉皮层细胞发生了一系列反应特性的改变,如:老年动物皮层细胞的方向选择性和方位选择性降低以及细胞反应的潜伏期延长。这些细胞水平的变化被认为是老年性视觉功能衰退的神经机制。为了更全面地了解衰老过程对视觉皮层的影响以及细胞反应改变与整体功能降低之间的关系,本研究采用活体动物细胞外单位记录的方法,比较了青年和老年猕猴初级视觉皮层细胞时间反应特性和空间反应特性的差异。研究结果发现:老年动物初级视觉皮层细胞的时间频率和空间频率敏感性明显比年轻动物降低。表现为老年动物初级视觉皮层细胞的最优时间和空间频率、空间分辨率(spatial resolution, SR)和较高时间截至频率(high temporal frequency cut-off, TF50)都显著低于年轻动物初级视觉皮层细胞,同时伴随着这些功能的降低,老年动物初级视觉皮层细胞的自发放增加,对视觉刺激的反应增加,但是信噪比却显著降低。这些结果表明,老年动物初级视觉皮层细胞的功能在老化过程中都普遍降低。这可能是导致老年人视觉功能降低的原因。

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A series of Zn(II) and Cd(II) metal-organic frameworks, namely, [Zn(DFDA)] (1), [Cd(DFDA)(C2H5OH)] (2), [Zn-2(DFDA)(2)(L-1)(2)](2) center dot 3H(2)O (3), [Cd-2(DFDA)(2)(L-1)(2)] (4), [Zn(DFDA)(L-2)] (5), [Cd(DFDA)(L-2)(DMF)] (6), and [Zn(DFDA)(L-3)] (7) (where DFDA = 9,9-dipropylfluorene-2,7-dicarboxylate anion, L-1 = 1,4-bis(imidazol-1-ylmethyl)benzene, L-2 = 1,1'-(1,4-butanediyl) bis(imidazole), L-3 = 2,2'-bipyridine) have been synthesized under hydrothermal conditions and structurally characterized. Compound 1 exhibits a three-dimensional (3D framework containing one-dimensional (1D) Zn(II)-O clusters, with (4(8).6(7)) topology. Compound 2 contains hydrophobic channels built from infinite 1D Cd(II)-O clusters, with (4(8).5(4).6(3)) topology.

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通过Stille偶联反应合成了5,5″-二辛基-2,2′∶5′2″-三联[3,2-b]并二噻吩,并对该化合物的物理化学性质以及真空蒸镀薄膜的结构和形貌进行了详细表征.以这一化合物作为半导体层、采用顶电极结构制备了有机薄膜晶体管,并对薄膜生长基底温度做了优化,发现基底温度为100℃时器件性能最好,迁移率达到0.13 cm2/V.s,开关比为7×103,阈值电压为-19V.

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Reaction of 3-(2-pyridylmethyl)indenyl lithium (1) with LnI(2)(THF)(2) (Ln = Sm, Yb) in THF produced the divalent organolanthanides (C5H4NCH2C9H6)(2)Ln(II)(THF) (Ln = Sm (2), Yb (3)) in high yield. 1 reacts with LnCl(3) (Ln = Nd, Sm, Yb) in THF to give bis(3-(2-pyridylmethyl)indenyl) lanthanide chlorides (C5H4NCH2C9H6)(2)Ln(III)Cl (Ln = Nd (4), Sm (5)) and the unexpected divalent lanthanides 3 (Ln = Yb). Complexes 2-5 show more stable in air than the non-functionalized analogues. X-ray structural analyses of 2-4 were performed. 2 and 3 belong to the high symmetrical space group (Cmcm) with the same structures, they are THF-solvated 9-coordinate monomeric in the solid state, while 4 is an unsolvated 9-coordinate monomer with a trans arrangement of both the side-arms and indenyl rings in the solid state. Additionally, 2 and 3 show moderate polymerization activities for F-caprolactone (CL).

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X-2-y(2)SiO(5):A (A = Eu3+, Tb3+, Ce3+) phosphor films and their patterning were fabricated by a sol-gel process combined with a soft lithography. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), scanning electron microscopy (SEM) optical microscopy and photoluminescence (PL) were used to characterize the resulting films. The results of XRD indicated that the films began to crystallize at 900 degreesC with X-1-Y2SiO5, which transformed completely to X-2-Y2SiO5 at 1250 degreesC. Patterned thin films with different band widths (5 pin spaced by 5 pm and 16 pm spaced by 24 pm) were obtained by a soft lithography technique (micromoulding in capillaries, MIMIC). The SEM and AFM study revealed that the nonpattemed phosphor films were uniform and crack free, and the films mainly consisted of closely packed grains with an average size of 350 run. The doped rare earth ions (A) showed their characteristic emissions in X-2-Y2SiO5 phosphor films, i.e., D-5(0)-F-7(J) (J = 0, 1, 2,3,4) for Eu3+, D-5(3), (4)-F-7(J) (J = 6, 5, 4, 3) for Tb3+ and 5d (D-2)-4f (F-2(2/5),(2/7)) for Ce3+, respectively. The optimum doping concentrations for EU3+, Tb3+ were determined to be 13 and 8 mol% of Y3+ in X-2-Y2SiO5 films, respectively.

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近十几年来,结晶性间同立构1,2-聚丁二烯引起人们的广泛关注,但绝大多数研究工作集中在聚合物的制备、物理性质和应用方面[1~3],对于其结晶行为和晶体结构则未见报道 .原因是间同立构1,2-聚丁二烯分子侧链含有大量的双键,在较高温度下很容易交联 ,特别是高间规度的聚合物 ,由于其熔融温度高 (>200℃ )则更易产生交联,这给结晶行为和结构研究带来很大困难.结晶性间同立构1,2-聚丁二烯的晶体结构为平面锯齿链正交堆砌,Pacm空间群[4].我们曾报道了结晶性间同立构1,2-聚丁二烯的合成和溶液浇铸膜的板条状结构[5],本文采用薄膜熔体结晶的方法第一次成功地获得了间同立构1,2-聚丁二烯的单晶,并通过电子显微学和电子衍射技术确定了其晶体结构.1 实验部分1.1间同立构1,2-聚丁二烯的制备采用乙酰基丙酮铁 [Fe(acac) ]3、三异丁基铝 [Al(i-Bu)3]和氢化亚磷酸二乙酯 (DEP)的新催化体系制备间同立构1,2-聚丁二烯,具体合成路线参见文献 [5].本文所选用聚合物的1,2单元含量为 89.3 % ,间规度为 ...

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Silicate oxyapatite La-9.33 (SiO6)(4)O-2:A (A = Eu3+, Tb3+ and/or Ce3+) phosphor films and their patterning were fabricated by a sol-gel process combined with soft lithography. X-ray diffraction (XRD), Fourier transform infrared spectroscopy, atomic force microscopy, optical microscopy and photoluminescence spectra, as well as lifetimes, were used to characterize the resulting films. The results of XRD indicated that the films began to crystallize at 800degreesC and the crystallinity increased with the increase in annealing temperatures. Transparent nonpatterned phosphor films were uniform and crack-free, which mainly consisted of rodlike grains with a size between 150 and 210 nm. Patterned thin films with different bandwidths (20, 50 mum) were obtained by the micromoulding in capillaries technique. The doped rare earth ions (Eu3+, Tb3+ and Ce3+) showed their characteristic emission in crystalline La-9.33(SiO6)(4)O-2 phosphor films, i.e. Eu3+ D-5(0)-F-7(J) (J = 0, 1, 2, 3, 4), Tb3+ D-5(3,4)-F-7(J) (J = 3, 4, 5, 6) and Ce3+ 5d (D-2)-4f (F-2(2/5), F-2(2/7)) emissions, respectively. Both the lifetimes and PL intensity of the Eu3+, Tb3+ ions increased with increasing annealing temperature from 800 to 1100 degreesC, and the optimum concentrations for Eu3+, Tb3+ were determined to be 9 and 7 mol% of La3+ in La-9.33(SiO6)(4)O-2 films, respectively. An energy transfer from Ce3+ to Tb3+ was observed in the La-9.33(SiO6)(4)O-2:Ce, Tb phosphor films, and the energy transfer efficiency was estimated as a function of Tb3+ concentration.

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Reactions of the Rh hydrido complex [Rh(H)(2)(PPh3)(2)(EtOH)(2)]ClO4 (1) With nitrogen ligands such as 2-(4-thiazolyl)benzimidazole (tbz). pyridazine (pdz), imidazole (im) and pyrimidine (pmd) in CH,Cl, afforded Various mononuclear Rh hydrido complexes, [Rh(H)(2)(PPh3)(2)(tbz)]CIO4 (2), [Rh(H)(2)(PPh3)(2)(pdZ)(2)]ClO(4)(.)2CH(2)Cl(2) (3). [Rh(H)Cl(PPh3)(2)(pdz)(2)](ClO4CH2Cl2)-C-. (4). [Rh(H)(2)(PPh3)(2)(im)(2)]ClO(4)(.)2CH(2)Cl(2) (5). [Rh(H)Cl(PPh3)(2)(im)(2)](ClO4CH2Cl2)-C-. (6). [Rh(H)(2)(PPh3)(2)(pmd)(2)](ClO4CH2Cl2)-C-. (7) and the Rh non-hydrido complex [RhCl2(pmd)(4)]ClO4 (8). The Rh complexes 2. 3, 5 and 6 were crystallographically characterized. The formation process was monitored by H-1 NMR and UV-Vis spectra. In all the Rh hydrido complexes, the Rh atom is coordinated by two PPh3. ligands in trans-positions and two nitrogen ligands in the cis-positions. The remaining sites Lire occupied by one or two hydride atoms to form a saturated 18-electron framework in a slightly distorted octahedral geometry. For complex 2 an appreciable inter-molecular pi interaction is observed between planes of tbz and PPh3 ligands, while an intra-molecular hydrogen bonding interaction between C-H and Cl atoms is found in complex 6.

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用离子色谱法测定AgNO_3溶液中的Cl~-、NO_2~-和SO_4~(2-),以5.0mmol/L Na_2CO_3-5.0mmol/L NaHCO_3混合溶液作淋洗液,采用离子交换法将AgNO_3转换成KNO_3,以除去Ag~+。讨论了NO_3~-对Cl~-、NO_2~-和SO_4~(2-)测定的影响。AgNO_3溶液中Cl~-、NO_2~-和SO_4~(2-)的回收率分别为93.3%、108%和94%。

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应用扫描电化学显微镜和微电极技术研究了水 / 1,2 二氯乙烷界面上的反向电子转移反应 .分别以K4 Fe(CN) 6和 7,7,8,8 四氰代二甲基苯醌 (TCNQ)作为水相和有机相的电活性物质 ,通过选择合理的共同离子 (TPAs+与TBA+)来控制界面电位差 ,实现了这一在热力学上通常不可能实现的反向电子转移反应 .利用扫描电化学显微镜给出的正负反馈信息 ,研究了界面电位差驱动的液 /液界面上的电子转移反应 ,并进一步得到了在不同的共同离子浓度比时 ,此异相界面反应速率常数kf 为 1 3× 10 -31 8× 10 -2 cm/s(共同离子为TBA+)和 2 5× 10 -32 8× 10 -2 cm/s(共同离子为TPAs+) .验证了此反应速率常数kf 是由界面电位差所决定的 .在此实验条件下 ,此反应速率常数kf 与界面电位差的关系遵守Butler Volmer公式 .

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本文用核磁共振 (NMR)波谱和化学定磷法研究了 Ce(SO4) 2 对 5′-腺嘌呤核苷酸 (5′- AMP)及5′-鸟嘌呤核苷酸 (5′- GMP)的水解断裂作用。结果表明 :Ce(SO4) 2 在 37℃ ,酸性条件下使 5′- AMP断裂为腺嘌呤核苷 (A)及无机磷 ,使 5′- GMP断裂为鸟嘌呤核苷 (G)及无机磷 ,SO2 -4 浓度及酸强度对 5′- AMP及 5′- GMP的水解断裂程度有很大影响 ,并对其水解断裂机制进行了研究。

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用ESR方法研究了[Cu(IO5OH)2]5-离子配合物中127I核的超超精细相互作用,旨在证实在碘离子上存在未成对电子自旋和找到一种解释Cu2+离子中电子离域的机制。根据ESR参数的计算指出碘离子上自旋密度为0.77%。

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本文在pH5.5的乙酸-乙酸钠介质中,对以5-Br-PADAP作指示剂络合滴定法连续测定锌和铜进行了研究,对滴定的pH值及指示剂用量进行了选择,试验了锌、铜不同配比的滴定结果,研究了共存离子的干扰。实验表明,用5-Br-PADAP作指示剂、EDTA作滴定剂连续测定锌和铜,滴定终点颜色变化敏锐,准确度高,锌和铜均在0~20mg范围内与EDTA用量成正比,锌、铜比例在1:10~10:1范围内相互无影响,方法用于标样及金矿中锌、铜的连续测定,结果满意。