Influence of 5A-Type Zeolite Powder on Tetrahydrofuran Hydrate Formation and Dissociation Process

Visual observations of tetrahydrofuran (THF) hydrate formation and dissociation processes with 5A-type zeolite powder were made at normal atmospheric conditions and below zero temperature by microscope. Results indicate that 5A-type zeolite powder can promote THF hydrate growth. At the same time, in the presence of 5A-type zeolite, agglomerated crystals and vein-like crystals of THF hydrate were also formed. SA-type zeolite powder increases the crystallization temperature and decreases the dissociation temperature. The particle size distribution of 5A-type zeolite powder influences THF hydrate formation and its dissociation characteristics significantly.

Absorption spectra of Se-8-ring clusters in zeolite 5A

Samples with different weight ratio of Se to zeolite 5A (Se concentration) have been prepared by loading Se into the pores of zeolite 5A, and the measuerments of the absorption and Raman spectra have been carried out for the prepared samples. The measured absorption edges of the samples are close to the value for monoclinic Se containing Se-8-ring, suggesting the formation of Se-8-ring clusters(1) in the pores. The continuous and broadening features of the absorption spectra are interpreted by the strong electron-nucleus coupling in the Se-8-ring cluster. The absorption edges are red shifted with the increase of the Se concentration. It is tentatively attributed to two reasons. One is the existence of the double Se-8-ring cluster in the high Se concentration samples, and the other is that for the strong electron-nucleus coupling cluster, the absorption edge of the clusters system will be red shifted with the increase of the cluster concentration in the clusters system. A single broad band at about 262 cm(-1) is observed in the Raman spectra, which further supports the formation of Se-8-ring clusters. (C) 1997 Published by Elsevier Science S.A.

Absorption and Raman spectra of Se-8-ring clusters in zeolite 5A

Samples with different weight ratio of Se to zeolite 5A (Se composition) have been prepared by loading Se into the cages of zeolite 5A and the measurements of the absorption and Raman spectra have been carried out for the prepared samples. The measured absorption edges of the samples close and blue shifted to the value for monoclinic Se containing Se-8-ring, suggesting the formation of Se-8-ring clusters dagger in the cages. The continuous and broadening features of the absorption spectra are interpreted by the strong electron-phonon coupling in Se-8-ring clusters. The sample with high Se composition has a red shift of the absorption band edge relative to the samples with less Se composition. It is tentatively attributed to the reason that with different Se composition, single Se-8-ring clusters and double Se-8-ring clusters are formed in the cages of zeolite 5A. A single broad band at about 262 cm(-1) is observed in the Raman spectra, that gives the further support of the formation of Se-8-ring clusters. Copyright (C) 1996 Elsevier Science Ltd

线性压电材料的有限元分析

本文利用线性压电学理论，编制了线性压电材料四结点等参有限元程序，进行了校核，并对PZT-5A材料压电智能元件和压电材料标准断裂试进行了计算，计算包括：①采用实际工程应用的压电智能元件尺寸，计算了元件的压电响应；并针对元件内部电极尖端区域容易引起破坏的现象，计算了该区域的奇异应力、应变场及电场。②计算了加力和加电两种情况下压电材料标准断裂试件应力强度因子影响系数F_I和电位移强度因子影响系数F_D。裂纹面边界条件采用D-P条件，试件包括紧凑拉伸标准试件和三点弯曲标准试件。③应用Lagrange乘子法将Parton裂纹边界条件加于有限元程序中，计算了上述两种标准断裂试件的F_I和F_D，计算结果与采用D-P裂纹边界条件的计算结果有很大差异。

国产YAP：Ce闪烁晶体的相对探测能力测量

为适应在n、γ昆合脉冲辐射场中对低强度快脉冲y辐射测量的需要，近年国内新研制出实用型YAlO3：Ce（YAP：Ce）快响应无机闪烁晶体。我们使用脉冲线性电流大于1．5A的光电倍增管，分别配置这种晶体以及CeF3、NaI等晶体构成闪烁探测器，在放射性标准源场中，对晶体的相对探测能力进行测量。测量结果表明：国产新型YAP：Ce无机晶体对这1．25MeV射线的探测能力比同体积的CeF3平均高一个量级，是同体积NaI的40％左右；当晶体厚度小于2mm时，YAP：Ce与CeF2、NaI的输出比值分别大于16和44％，说明厚度越薄晶体的相对探测能力越强。

神农架地区米心水青冈林和锐齿槲栎林的格局与过程

本文对神农架地区广泛分布的米心水青冈林和锐齿槲栎林的种群和群落学特征、干扰历史、更新策略、生物量、生产量及元素循环特征进行了研究。得到如下结论： 1 米心水青冈林是神农架地区山地垂直分布的地带性植被类型，主要群落学特征为：（1）建群种明显，该区域主要有2种类型，即米心水青冈林和米心水青冈、锐齿槲栎林;（2）群落结构简单，但物种组成丰富，在6600m~2样地中出现高等植物（不含苔藓植物）77科150属271种，组成种类以蔷薇科、百合科、忍冬科、虎耳草科、樟科、杜鹃花科和壳斗科为主;（3）群落乔木层（占重要值的12％）和灌木层（占盖度的15％）中含有一定比例的常绿树种;（4）群落生活型以高位芽植物（70.89%）占绝对优势，其次为地面芽植物（15.50%）和地下芽植物(12.92%)。 2 米心水青冈是多主干的树种，萌枝现象普遍，但萌枝数量不同地点差异较大。通过萌枝产生的枝群体平均密度为257 ± 99.3n•hm~(-2)。枝群体的年龄结构表现为“幼龄个体数目较多型”和“中国年龄阶段数目较多型”，并且有较多的枝群体表现出一致的年龄结构。从整个群落米心水青冈的年龄结构来看，表现出发展型种群的特点。枝群体的分布格局为随机分布。9丛米心水青冈完整的年轮分析结果表明，它们萌枝的时间不是边疆的，而与森林的受干扰有关。根据83个圆盘和生长锥芯资料，米心水青冈在萌枝后成长为乔木层或林冠层的过程中，径向生长表现为5种模式。这是丛株内竞争的结果。萌枝在米心水青冈林的维持和发展过程中，具有重要的生态学作用。 3 锐齿槲栎林是神农架地区山地垂地分布的地带性植被类型，主要群落学特征为：（1）建群种明显，该区域主要有2种类型，即锐齿槲栎林和锐齿槲栎、米心水青冈林;（2）群落乔木层和灌木层中含有一定比例的常绿树种，和暖温带的落叶栎林有较大差异;（3）群落物种组成丰富，不仅具有典型的温带科属，还有典型亚热带分布的科属，组成种类主要以蔷薇科、百合科、忍冬科、虎耳草科、山茱萸科、杜鹃花科、壳斗科和樟科;（4）生活型以高位芽植物（66.32%）占绝对优势，其次为地面芽（23.51%）和地下芽（9.47%）植物。 4 通过样地调查、树干解析及直径分析法，对米心水青冈林和锐齿槲栎林受压和释压历史及更新策略进行了研究。米心水青冈直径生长表现为5种模式。而锐齿槲栎只表现为2种模式。85.9 ± 6.9%的米心水青冈有过受压过程，平均受压2.1 ± 0.8次，平均受压时间为47 ± 24.1a，最长受压时间73a，平均释压次数为1.6 ± 0.7次，平均释压时间为23 ± 21.5a，而60.83%的锐齿槲栎都均有1次受压。平均受压时间为19 ± 14a，受压后没有表现出释压过程。结合高生长和径向生长，认为米心水青冈是耐阴树种，它的更新策略是在林下形成苗性萌枝，在有林窗形成时释压生长进入乔木层;而锐齿槲栎是不耐阴树种，它的更新策略是通过产生大量种子，当有大的林窗时，幼苗在林窗内生长逐步进入乔木层。 5 神农架地区102-130a成熟米心水青冈林的生物量在251.31-358.63T•hm~(-2)之间，平均为288.70 ± 48.30T•~(-2)，20-60a锐齿槲栎林群落生物量在134.85-301.20T•hm~(-2)，平均为231.60 ± 78.10T•hm~(-2)。虽然米心水青冈林和锐齿槲栎林灌木层草本层及藤本植物组成很丰富，但二种类型森林生物量的95％以上集中在乔木层。乔木层生物量主要集中在少数优势种中。在米心水青冈林生物量从大到小的序列中，前5种植物分别占乔木层总生物量58.67%-96.37%不等，同样锐齿槲栎林前5种植物占群落生物量的68.13%-95.26%。常绿植物占乔木层生物量的比例变化较大，米心水青冈林中占2.85-18.70%，锐齿槲栎林中一般常绿植物占0.8-9.98%，只有1个锐齿槲栎林样地常绿植物（主要是粉白杜鹃）占乔木层生物量的44.04%。米心水青冈林生物量根冠比为0.27 ± 0.05，锐齿槲栎林为0.21 ± 0.06。神农架地区米心水青冈林的生物量，在成熟的欧洲水青冈林及日本的水青冈林生物量范围之内，而锐齿槲栎林生物量远远大于我国温带落叶栎林的生物量。 6 神农架地区102-130a米心水青冈林生产量范围在1857-2786g•m~(-2)•a~(-1)，平均为2330 ± 397 g•m~(-2)•a~(-1)。20-60a锐齿槲栎林的生产量范围在1319-2521 g•m~(-2)•a~(-1)，平均为1930 ± 498 g•m~(-2)•a~(-1)。米心水青冈林和锐齿槲栎林乔木层生产量占群落总生产量的95％以上，乔木层各器官生产量大小顺序为叶> 树干> 枝和根，其中叶生产量占乔木层的一半以上，达53.87 ± 2.72%（米心水青冈林）和57.31 ± 6.23%（锐齿槲栎林）。在乔木层生产量从大到小的序列中，前5种植物平均占乔木层总生产量的81.03 ± 13.94%（米心水青冈林，范围在62.75%-92.66%）和84.23 ± 9.68%（锐齿槲栎林，范围在68.54-95.11%）。米心水青冈林和锐齿槲栎林群落地下部分生产量占总生产量的比例分别为11.29 ± 1.02%和9.22 ± 2.72。和我国其它地区地带性植被类型相比。米心水青冈林和锐齿槲栎生产量是较高的，和亚热带绿阔叶林生产量接近，但在器官分配上两者差异较大。 7 米心水青冈林和锐齿槲栎林土壤均呈酸性。其中锐齿槲栎林地土壤酸性更强。土壤元素特征表现为Al>C>K>Mg>Ca>N>S、P的特点，富铝化作用明显。8种元素在群落优势植物不同部位含量差异较大，N、P、K、Ca、Mg基本上是以叶片含量最高，树干或根中最低。仅从叶片来看，元素特征表现为C>Ca、N>K>Mg>S>P、Al。优势植物的C/N和C/P显著高于暖温带落叶阔叶林优势植物。8种元素在米心水青冈林和锐齿槲栎林中积累量分别为147.09 ± 25.60和116.00 ± 37.63 Mg hm~(-2)a~(-1)，其中97％以上积累在群落乔木层。两种森林类型各元素的积累量都表现为C>Ca, N> K> Mg> P> S> Al的特点。米心水青风林和锐齿槲栎林8种元素的年存留量分别为6263 ± 90.8和5946 ±246 kg hm~(-2)a~(-1),其中N、P、K、Ca、Mg 5种主要营养元素的存留量分别为179.7 ± 18.2和169.4 ± 23.5kg hm~(-2) a~(-1)。两种森林类型各元素的存留量都表现为C> N> Ca> K> Mg> S> P> Al。

光系统II原初过程的微观反应动力学研究

本论文在国内首次利用飞秒吸收光谱技术对PSII颗粒和PSII 核心复合物两个不同层次的PSII样品的原初反应过程进行了研 究。实验采用 400nm 激发， 520～700nm探测，时间分辨率为 120fs。通过多指数拟合和全局分析，对不同波长下的多条衰减 曲线同时采用一套时间组分进行解析，得到了不同波长下的各个 组分的衰减相关差异吸收谱(DADS)。 在 PSII 颗粒的研究中，通过对所有衰减曲线进行数据拟合，解析出了0.16ps、2.8ps、8.6ps、20.9ps、38.8ps和一个非衰减的组分。分析它们各自在520nm～700nm范围内的不同吸收变 化特点，我们得到以下结论： 1．在LHCII中，同一单体同一层中的Chlb与Chla分子之间 的能量传递时间常数约为0.16ps左右; 2．LHCII同一单体中，同一层中的Chla分子之间的能量传递时间常数约为 2.8ps 左右。这与在纯化的 LHCII研究中认为的一3ps组分为不同层的 Chlb→Chla的能量传递过程不同; 3．在PSII颗粒中，8.6ps 组分是与光化学过程有关的时间常数，它可能是从 LHCII 色素蛋白复合物向反应中心等的能量传递及在反应中心中的原初电荷分离过程的平均时间常数; 4．LHCII中不同单体之间的Chla之间的能量传递时间常数约为20.9ps。 在PSII核心复合物的研究中，通过对所有衰减曲线进行数据拟合，解析出了0.35ps、2.9ps、11.2ps、20.lps、36.5ps和一个非衰减的组分。分析它们各自在520nm～700nm范围内的不同吸收变化特点，并与PSII颗粒复合物所得结果相比较，我们得出以下结论： 1．PSII内周天线中相邻 Chla 之间的能量传递时间常数约为 0.35ps左右，这比LHCII中相邻Chlb与Chla之间的能量传递时间常数( 0.16ps )要长;这说明内、外周天线色素蛋白复合物 具有不同的色素空间排列。可以预见在PSII核心天线中相邻叶绿素分子之间的距离要比 LHCII中相邻叶绿素分子的8.3—10.5A 的距离要大一些。这在以前的研究中，并没有见到报导; 2．PSII内周天线中不相邻的Chla之间的能量传递时间常数 约为11.2ps; 3．在PSII核心复合物研究中，2.9ps 和 20.lps 两个组分均与光化学反应过程有关，推测原初电荷分离过程可能是有辅助叶绿 素分子参与的两步反应。

点柄乳牛肝菌子实体中抗HIV-1活性成分

目的 研究点柄乳牛肝菌的化学成分,并对分离鉴定的化合物进行抗HIV-1的活性研究.方法 将野外采集的点柄乳牛肝菌子实体用溶剂提取,采用硅胶柱色谱进行分离,通过波谱技术(NMR,MS,IR等)对结构进行鉴定.结果 分离鉴定了9个化合物,分别为:酒渣碱(Ⅰ)、5a,8a-过氧麦角甾-6,22-二烯-3β-醇(Ⅱ)、麦角甾-5,7,22-三烯-3β-醇(Ⅲ)、麦角甾-5,7,22-三烯-3β-O-β-D-吡喃葡萄糖苷(Ⅳ)、尿嘧啶(Ⅴ))、硫代乙酸酐(Ⅵ)、硬脂酸(Ⅶ)、3-吡啶甲酸(Ⅷ)和D-阿洛糖醇(Ⅸ).结论 化合物Ⅰ为首次从高等真菌中分离.经生物活性测试,该化合物具有抗HIV-1活性,对C8166细胞的毒性较小,CC50为87.86 μg/mL,对HIV-1诱导C8166细胞形成合胞体抑制的EC50为7.27 μg/mL,治疗指数(TI值)为12.09.

大肠阻塞模型绵羊血浆及组织中血管紧张素-Ⅱ(AⅡ)含量的变化

为研究大肠阻塞动物血浆及组织中A Ⅱ含量的变化,研究以绵羊为实验动物,进行结肠结扎作为大肠阻塞 模型动物,用放射免疫法对其血浆和组织中的A Ⅱ含量进行了测定。结果发现:模型组绵羊动物血浆A Ⅱ含量在术 后呈上升趋势,从第2 天开始显著高于手术前及对照组( P < 01001) ,在术后第2 天的密集采样中低于手术前和对照 组( P < 0105) ,第4 天显著低于手术前和对照组( P < 0101) ;模型组动物右心室和结肠结扎点后段A Ⅱ含量降低( P < 0105) 。结果提示:大肠阻塞动物血浆A Ⅱ含量随病情的发展而迅速升高,与病情的严重程度呈明显正相关。

HORMONAL-REGULATION OF TISSUE-TYPE PLASMINOGEN-ACTIVATOR AND PLASMINOGEN-ACTIVATOR INHIBITOR TYPE-1 IN CULTURED MONKEY SERTOLI CELLS

Sertoli cells play a central role in the control and maintenance of spermatogenesis. Isolated Sertoli cells of mouse and rat testes have been shown to secrete plasminogen activator (PA) and a plasminogen activator inhibitor type-1 (PAI-1) in culture. In this study, we have investigated the hormonal regulation of PA and PAI-1 activities in cultured monkey Sertoli cells. Sertoli cells (5x10(5) cells/well) isolated from infant rhesus monkey testes were preincubated at 35 degrees C for 16 h in 24-well plates precoated with poly(D-lysine) (5 mu g/cm(2)) in 0.5 mi McCoy's 5a medium containing 5% of fetal calf serum and further incubated for 48 h in 0.5 mi serum-free medium with or without various hormones or other compounds, PA as well as PAI-1 activities in the conditioned media were assayed by fibrin overlay and reverse fibrin autography techniques respectively. The Sertoli cells in vitro secreted only tissue-type PA (tPA), no detectable amount of urokinase-type PA (uPA) could be observed, Monkey Sertoli cells were also capable of secreting PAI-1, Immunocytochemical studies indicated that both tPA and PAI-1 positive staining localized in the Sertoli cells, spermatids and residual bodies of the seminiferous epithelium; Northern blot analysis further confirmed the presence of both tPA and PAI-1 mRNA in monkey Sertoli cells. Addition of follicle-stimulating hormone (FSH) or cyclic adenosine monophosphate (cAMP) derivatives or cAMP-generating agents and gonadotrophin-releasing hormone (GnRH) agonist or phorbol ester (PMA) to the cell culture significantly increased tPA activity. PAI-1 activity in the culture was also enhanced by these reagents except 8-bromo-dibutyryl-cAMP, forskolin and 3-isobutyl-1-methylxanthin (MIX) which greatly stimulated tPA activity, whereas decreased PAI-1 activity, implying that neutralization of PAI-1 activity by tile high level of tPA in the conditioned media may occur. These data suggest that increased intracellular signals which activate protein kinase A (PKA), or protein kinase C (PKC) can modulate Sertoli cell tPA and PAI-1 activities, The concomitant induction of PA and PAI-1 by the same reagents in the Sertoli cells may reflect a finely tuned regulatory mechanism in which PAI-1 could limit the excession of the proteolysis.

三峡水库香溪河库湾主要营养盐的入库动态

基于香溪河及其主要支流高岚河的5a监测数据,估算三峡水库香溪河库湾氮磷营养盐的入库通量,并分析了氮磷营养盐的浓度及其通量的逐月动态。研究发现,每年大约有1623.49t总氮和331.85t总磷汇入香溪河库湾,其中,香溪河贡献了68.50%的总氮和91.74%的总磷。在这两条河流中,溶解无机氮是氮的主要存在形式;氮通量表现出夏季7月份偏高、春秋季次之、冬季较低的规律;面源污染是氮进入河道的主要途径。磷酸盐是香溪河磷的主要存在形式,而高岚河磷酸盐的含量则较低;香溪河磷通量的月均波动规律不明显,高岚河磷通量的高

EFFECT OF ELEVATED BICARBONATE CONCENTRATION ON GROWTH, CHLOROPHYLL A FLUORESCENCE AND ULTRA-STRUCTURE OF Microcystis aeruginosa (CYANOBACTERIUM)

The influence of bicarbonate (HCO3-) on Microcystis aeruginosa FACHB 905 was assessed in this study. Growth curves, chlorophyll a fluorescence and ultrastructure were measured at two HCO3- concentrations, 2.3 mM and 12.4 mM. A treatment of sodium chloride (NaCl) was also conducted alongside to establish the influence level of sodium. It was found that upon treatment with elevated HCO3- concentrations of 2.3 mM and 12.4 mM, cell densities were 13% and 27% (respectively) higher than controls. In photosynthetic performance, elevated HCO3- concentration initially stimulated Fv/Fm at the prophase of culture and then subsequently inhibited it. The inhibition of 2.3mM was higher than that of 12.4mM HCO3-. The maximum relative electron transport rate (ETRmax) exhibited inhibition at elevated HCO3- concentrations. DI0/CS was decreased at 2.3 mM and increased at 12.4mM. In the case of both treatments. ABS/CSI TR0/CS, ET0/CS, RC/CS0 and RC/CSm were decreased by elevated HCO3- concentrations, which indicated damage to photosynthetic apparati and an inactivation of a fraction of reaction centers. This point was also proven by ultrastructural photos. High HCO3--exposed cells lost the characteristic photosynthetic membrane arrangement compared with the control and high salinity treated samples. At the 2.3mM concentration of HCO3-. damage to photosynthetic apparati caused decreased photosynthetic activity. These findings suggested that elevated HCO3- concentration stimulated the growth and photosynthesis of M. aeruginosa FACHB 905 in a short time. Exposure to high HCO3- concentrations for a longer period of time will damage photosynthetic apparatus. In addition, the ultrastructure indicated that elevated HCO3--concentration lead to photosynthetic apparati damage. In our experiment, it was observed that the inhibition effect of 2.3mM HCO3- was higher than that of 12.4mM HCO3-. We hypothesized that M. aeruginosa FACHB 905 induced a protective mechanism under high concentrations of HCO3-.

Investigation on InGaAs/InAlAs quantum cascade lasers

The preparation and main characteristics of the InGaAs/InAlAs quantum cascade laser were given. The device has a reinforced ridge waveguide structure. The threshold current obtained at 80K is about 0. 5A, and the corresponding threshold current density is about 5kA/cm(2).

Preparation of I-2 clusters and their absorption spectra

Samples have been prepared at different temperatures by loading It molecules into the cages of zeolite 5A, and the measurements of the absorption spectra have been carried out for the prepared samples. It is shown that 12 molecular clusters are formed in the cages of zeolite 5A, and it is also found that molecular clusters which are bonded with intermolecular forces have an important feature, namely, the intermolecular distance in molecular clusters can be changed on different preparing conditions and the blue shift of absorption edges can not be as the criterion of forming molecular clusters.

高温气冷堆 He 载气中 H_2O 和 CO_2 吸附净化的实验研究

通过对高温气冷堆He载气中的H2O和CO2在5A分子筛固定床上吸附净化的实验研究，得到了吸附穿透曲线，获得了5A分子筛床对H2O和CO2的动态吸附规律。实验考察了吸附温度、工作压力、杂质浓度、流速及床层高度等因素对H2O和CO2单吸附及共吸附的吸附容量及转效时间的影响，获得了最佳运行参数。实验研究结果表明：净化后He气中H2O和CO2的质量分数低于10－5，满足了净化系统的要求，为高温气冷堆中5A分子筛固定床装置提供了可靠的设计数据。