CHARACTERIZATION OF A POTASSIUM-PROMOTED COBALT MOLYBDENUM ALUMINA WATER-GAS SHIFT CATALYST

A series of potassium-promoted CoMo/Al2O3 has been investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature-programmed reduction (TPR). CoMoO4 was found in the CoMo/Al2O3 catalyst by XRD and is destroyed by the presence of potassium. The reducibility of molybdenum is enhanced by potassium in the CoMoK/Al2O3 catalyst and is easier to reduce to Mo(IV) during sulfidation. In the oxidic state catalyst cobalt is increased on the surface by the addition of potassium. After sulfidation this phenomena disappeared, the distribution of cobalt remains at a constant level and is unaffected by the potassium content. The addition of potassium leads to a monotonical decrease of the molybdenum dispersion with the impregnating amount of potassium in the oxidic state catalyst but is more complicated after sulfidation. Potassium is well dispersed on the surface in both the oxidic and sulfided state. The activity in the water-gas shift reaction was correlated with the potassium content of CoMoK/Al2O3.

THE CATALYTIC BEHAVIOR AND REACTION-MECHANISM OF THE BI-CE-O SYSTEM CATALYSTS IN THE OXIDATIVE DEHYDROAROMATIZATION OF PROPYLENE

Oxidative dehydroaromatization of propylene was investigated by the pulse technique over two kinds of single oxide catalysts. With the Bi2O3 catalyst, the main dimer product was 1,5-hexadiene, and the dimerization activity was stable to pulse number even if the catalyst was partly reduced to the bulk. With the CeO2 catalyst, benzene was mainly formed instead of 1,5-hexadiene, but the activity decreased rapidly with increasing pulse number, indicating that only the lattice oxygen near the catalyst surface could be used for oxidative dimerization and the further aromatization. The Bi-Ce-O system catalyst was found in this study to give higher aromatization activity and showed better stability, compared to the Bi-Sn-O catalyst. Although the Bi-Ce-O catalyst was only a mixture of the two component oxides from X-ray diffraction analysis, there was a significant combination effect on the selectivity to benzene. The highest and the most stable selectivity of benzene was obtained at Bi/Ce = 1. In the TPD spectrum of Bi-Ce-O catalyst, there are not only the lattice oxygen (beta-oxygen) over 620-degrees-C due to the reduction of Bi2O3, but also a great deal of the alpha-oxygen desorbed about 400-degrees-C, which is considered the absorbed oxygen in the bulk. This absorbed oxygen could probably be a compensation of the lattice oxygen through the route of gaseous --> absorbed --> lattice oxygen in the binary catalyst system. By the kinetic study on the Bi-Ce-O catalyst, the dimer formation rate was the first-order with respect to the partial pressure of propylene and zero-order of oxygen. Although detail investigation would be made further, it was considered that the complete oxidation of propylene would mainly take place parallelly on some different sites, and the rate-determining step of propylene dimerization occurred probably between an adosrbed propylene and a gaseous one by an Eley-Rideal type mechanism.

异戊二烯均相聚合催化剂

分别用C_6H_5CH_2Cl,CH_2-CHSiCl_3,CH_ SiHCl_2,(CH_3)_2SiCl_2,(CH_3)_3CCl,CH_2—CHCH_2Cl,Cl_3SiCH_2CH_2SiCl_3代替非均相催化剂Nd(naph)_3-Al_2Et_3Cl-Al(i-Bu)_2H(简称Nd-Cl-Al)中的助催化剂后,除C_6H_5CH_2Cl,CH_2=CHSiCl_3,CH_SiHCl_2形成悬浊催化剂外,在Cl/Nd<8(mol比)时,其他氯化物均形成均相催化剂,并能催化异戊二烯均相聚合,得到顺式-1,4含量约95％,[η]约3 dL/g的聚合物。分别用(CH_3)_3CCl和(CH_3)_2SiCl_2代替Cl所组成的两催化剂,其催化活性接近,最佳Al/Nd和Cl/Nd值分别为40和2.5;异戊二烯浓度为10％—20％时,转化率不随其浓度的改变而变化。符合一级反应动力学特征。

NdCl_3·3P350-AlR_3二元催化体系对双烯烃的定向聚合

由氯化稀土的不同种类磷酸酯配合物与三烷基铝组成的Ziegler-Natta催化剂对双烯烃聚合的研究已有报道,其中聚合活性最高的NdCl_3·3P350—AlR_3二元催化体系对丁二烯溶液聚合及异戊二烯本体聚合的详细研究尚未见报道,本文考察了该体系对双烯烃的定向聚合能力,通过二元体系与相应的催化剂活性体聚合规律的对比,提高对稀土催化聚合反应过程的认识。

Ce:BaAlF_5晶体生长及其光谱特性

采用坩埚下降法生长了 Ce:BaAlF_5单晶、X 射线衍射表明其结构为α-BaAlF_5构型,属于正交晶系,晶胞参数为α=5.146(?),b=7.191(?),c=19.647(?)。测定了晶体的反射光谱、吸收光漕、激发光谱和荧光光谱。Ce~(3+)离子在290nm 附近有一个强吸收峰,为4f-5d 能级的跃迁。在292nm 激发下,有306.5nm 和324nm 两个发射峰、即Ce~(3+)的~2D 能级到~2F_5/2和~2F_7/2能级的跃迁发射。晶体在紫外光照射下发紫光和兰白光。在254nm 激发下,除了 Ce_~(3+)的发射峰,还存在351nm和494nm 两个发光峰,前者与 Ce~(3+)的324nm 发射峰部分重叠,后者为对称性较好的宽带峰。这两个发光峰被认为是晶体缺陷产生的色心发光。

Molecular cloning, characterization and mRNA expression of peroxiredoxin in Zhikong scallop Chlamys farreri

Peroxiredoxin V (PRX V) is known as an atypical 2-cysteine peroxiredoxin that protects the organisms against various oxidative stresses and functions in signal transduction. The cDNA of a PRX V gene (designated as CfPRX) was cloned from scallop Chlamys farreri. The full-length sequence of CfPRX cDNA was of 2,179 bp with a 564 bp open reading frame encoding a peptide of 187 amino acids. Sequence comparison showed that CfPRX shared higher identities with PRX Vs than that with other isoforms of PRX, indicating CfPRX was a member of the PRX V family. Fluorescent real-time quantitative PCR analysis revealed the presence of CfPRX transcripts in gill filaments, adductor muscle, heart, gonad, kidney and hemocytes, and the stimulation of Listonella anguillarum significantly (P < 0.01) enhanced the mRNA expression of CfPRX in hemocyte. These results indicated that CfPRX was a constitutive and inducible acute-phase protein which was involved in the immune resistance to L. anguillarum stimulation.

The complete amino acid sequence of growth hormone and partial amino acid sequence of prolactin and somatolactin from sea perch (Lateolabrax japonicus)

Growth hormone (GH), prolactin (PRL) and somatolactin (SL) were purified simultaneously under alkaline condition (pH 9.0) from pituitary glands of sea perch (Lateolabrax japonicas) by a two-step procedure involving gel filtration on Sephadex G-100 and reverse-phase high-performance liquid chromatography (rpHPLC). At each step of purification, fractions were monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and by immunoblotting with chum salmon GH. PRL and SL antisera. The yields of sea perch GH, PRL and SL were 4.2, 1.0 and 0.28 mg/g wet tissue, respectively. The molecular weights of 19,200 and 20,370 Da were estimated by SDS-PAGE for sea perch GH and PRL, respectively. Two forms of sea perch SL were found: one (28,400 Da) is probably glycosylated, while the other one (23,200 Da) is believed to be deglycosylated. GH bioactivity was examined by an in vivo assay. Intraperitoneal injection of sea perch GH at a dose of 0.01 and 0.1 mug/g body weight at 7-day intervals resulted in a significant increase in body weight and length of juvenile rainbow trout. The complete sea-perch GH amino acid sequence of 187 residues was determined by sequencing fragments cleaved by chemicals and enzymes. Alignment of sea-perch GH with those of other fish GHs revealed that sea-perch GH is most similar to advanced marine fish, such as tuna, gilthead sea bream, yellowfin porgy, red sea bream, bonito and yellow tail with 98.4, 96.2%, 95.7%, 95.2%, 94.1% and 91% sequence identity, respectively. Sea-perch GH has low identity to Atlantic cod (76.5%), hardtail (73.3%), flounder (68.4%), chum salmon (66.3%), carp (54%) and blue shark (38%). Partial amino-acid sequences of 127 of sea-perch PRL and the N-terminal of 16 amino-acid sequence of sea-perch SL have been determined. The data show that sea-perch PRL has a slightly higher sequence identity with tilapia PRL( 73.2%) than with chum salmon PRL(70%) in this 127 amino-acid sequence. (C) 2001 Elsevier Science B.V. All rights reserved.

Preliminary analysis of grain-size populations with environmentally sensitive terrigenous components in marginal sea setting

Terrigenous components were separated from the bulk sediment of Core A7 from the Okinawa Trough and Core A37 from the Ryukru Trench and grain-size distributions of these sub-samples were analyzed. Based upon an analysis of the grain-size data of the two sedimentary sequences, grain-size populations are identified to be sensitive to sedimentary environmental changes. The modal values and size ranges of the two main grain-size populations in Core A7 are evidently different from those of Core A37, indicating the spatial variability of sediment sources and transport processes between the two places. The downcore variations in the content of the environmentally sensitive grain-size populations reveal that during the accumulation of sedimentary material the environment remained relatively stable at the site where Core A7 was collected, except for the apparent events for the formation of two turbidite layers and a volcanic ash layer. However, the sedimentary sequence of Core A37 shows six sedimentary cycles, indicating a highly variable sedimentary environment at this location.

He, Ne and Ar isotopic composition of Fe-Mn crusts from the western and central Pacific Ocean and implications for their genesis

The noble gas nuclide abundances and isotopic ratios of the upmost layer of Fe-Mn crusts from the western and central Pacific Ocean have been determined. The results indicate that the He and Ar nuclide abundances and isotopic ratios can be classified into two types: low He-3/He-4 type and high He-3/He-4 type. The low He-3/He-4 type is characterized by high He-4 abundances of 191x10(-9) cm(3.)STP(.)g(-1) on average, with variable He-4, Ne-20 and Ar-40 abundances in the range (42.8-421)x10(-9) cm(3.)STP(.)g(-1), (5.40-141)x10(-9)cm(3.)STP(.)g(-1), and (773-10976)x10(-9) cm(3.)STP(.)g(-1), respectively. The high He-3/He-4 samples are characterized by low He-4 abundances of 11.7x10(-9) cm(3.)STP(.)g(-1) on average, with He-4, Ne-20 and Ar-40 abundances in the range of (7.57-17.4)x10(-9) cm(3.)STP(.)g(-1), (110.4-25.5)x10(-9) cm(3.)STP(.)g(-1) and (5354-9050)x10(-9) cm(3.)STP(.)g(-1), respectively. The low He-3/He-4 samples have He-3/He-4 ratios (with RIRA ratios of 2.04-2.92) which are lower than those of MORB (R/R-A=8 +/- 1) and Ar-40/Ar-36 ratios (447-543) which are higher than those of air (295.5). The high He-3/He-4 samples have He-3/He-4 ratios (with R/R-A ratios of 10.4-12.0) slightly higher than those of MORB (R/R-A=8 +/- 1) and Ar-40/Ar-36 ratios (293-299) very similar to those of air (295.5). The Ne isotopic ratios (Ne-20/Ne-22 and Ne-21/Ne-22 ratios of 10.3-10.9 and 0.02774-0.03039, respectively) and the Ar-38/Ar-36 ratios (0.1886-0.1963) have narrow ranges which are very similar to those of air (the Ne-20/Ne-22, Ne-21/Ne-22, Ar-38/Ar-36 ratios of 9.80, 0.029 and 0.187, respectively), and cannot be differentiated into different groups. The noble gas nuclide abundances and isotopic ratios, together with their regional variability, suggest that the noble gases in the Fe-Mn crusts originate primarily from the lower mantle. The low He-3/He-4 type and high He-3/He-4 type samples have noble gas characteristics similar to those of HIMU (High U/Pb Mantle)- and EM (Enriched Mantle)-type mantle material, respectively. The low He-3/He-4 type samples with HIMU-type noble gas isotopic ratios occur in the Magellan Seamounts, Marcus-Wake Seamounts, Marshall Island Chain and the Mid-Pacific Seamounts whereas the high He-3/He-4 type samples with EM-type noble gas isotopic ratios occur in the Line Island Chain. This difference in noble gas characteristics of these crust types implies that the Magellan Seamounts, Marcus-Wake Seamounts, Marshall Island Chain, and the Mid-Pacific Seamounts originated from HIMU-type lower mantle material whereas the Line Island Chain originated from EM-type lower mantle material. This finding is consistent with variations in the Pb-isotope and trace element signatures in the seamount lavas. Differences in the mantle surce may therefore be responsible for variations in the noble gas abundances and isotopic ratios in the Fe-Mn crusts. Mantle degassing appears to be the principal factor controlling noble gas isotopic abundances in Fe-Mn crusts. Decay of radioactive isotopes has a negligible influence on the nuclide abundances and isotopic ratios of noble gases in these crusts on the timescale of their formation.

Os isotope dating and growth hiatuses of Co-rich crust from central Pacific

Up to now, accurate determination of the growth age and hiatuses of the Co-rich crust is still a difficult work, which constrains the researches on the genesis, growth process, controlling factors, regional tectonics, paleo-oceanographic background, etc. of the Co-rich crust. This paper describes our work in determining the initial growth age of the Co-rich crust to be of the late Cretaceous Campanian Stage (about 75-80 Ma), by selecting the Co-rich crust with clear multi-layer structures in a central Pacific seamount for layer-by-layer sample analysis and using a number of chronological methods, such as Co flux dating, dating by correlation with Os-187/Os-188 evolution curves of seawater, and stratigraphic division by calcareous nannofossils. We have also discovered growth hiatuses with different time intervals in the early Paleocene, middle Eocene, late Eocene and early-middle Miocene, respectively. These results have provided an important age background for further researches on the Co-rich crust growth process and the paleo-oceanographic environment evolution thereby revealed in the said region.

利用两种大型海藻制备生物能源的探索研究

生物质燃料乙醇和沼气都属于发展潜力巨大的生物质能源，大力发展生物质燃料乙醇和沼气对解决当今能源危机、环境污染问题和促进我国经济发展具有重要意义。 本文就海带化工废弃物——海带渣糖化技术、浒苔糖化技术及初步酒精发酵技术、海带沼气发酵技术、浒苔沼气发酵技术进行了可行性研究。 1、海带渣总糖含量为52.6%，海带渣总糖中葡萄糖含量占90.9%，另外还有少量的半乳糖、甘露糖和木糖，这说明海带渣是非常优良的能源生物质。 2、海带渣糖化工艺采取稀硫酸预处理后纤维素酶酶解产糖工艺。海带渣最佳稀硫酸预处理条件为预处理温度121℃、硫酸浓度0.6%、预处理时间60 min，此时海带渣纤维素酶解产糖可达187.8 mg/g干藻。 3、优化了预处理海带渣纤维素酶酶解产糖工艺。各因素对海带渣酶解产糖的影响依次为：pH>温度>时间>酶用量，海带渣纤维素酶解产糖的最佳条件为温度45℃、pH5.2、时间48小时、酶用量16 mg/g干藻，此时糖产量为238.9 mg/g干藻。 4、浒苔总糖含量为67.2%，浒苔总糖主要有葡萄糖、木糖、葡萄糖醛酸和鼠李糖组成，其中葡萄糖和木糖可以做为酒精发酵的原料，这两种糖占总糖含量的51%。 5、以鲜浒苔为原料研究了浒苔稀硫酸水解工艺和纤维素酶酶解工艺。发现浒苔酸水解产糖效果明显优于纤维素酶酶解。 6、以干浒苔为原料研究了浒苔酸解工艺。硫酸水解干浒苔产糖能力优于盐酸、磷酸和马来酸，水解时间为60 min、硫酸浓度为1.8%的时候可用于酒精发酵的糖（葡萄糖和木糖）总产量达到最大值为230.5 mg/g干浒苔，占此条件下总还原糖产量的48.6%。同时发现干浒苔比鲜浒苔更易被硫酸水解产糖。 7、初步研究了浒苔酒精发酵工艺。初步工艺中酒精产量较低、测得酒精在发酵液中浓度为0.23%（v/v），后续工作中需要对酒精发酵工艺进行优化。 8、海带与牛粪比例为4:1（w/w）是海带与牛粪联合厌氧消化的最佳比例，此时产气时间最长，达到37天，总产气量最高，达到13600 mL。 9、在海带与牛粪联合厌氧消化中，增加接种量到15 g（干重）时发酵周期为39天，总产气量为14630 mL，TS产气量为152.4 mL/gTS，接种量为21 g（干重）时发酵周期为36天，总产气量为14090 mL，TS产气量为138.1 mL/gTS，可见适当增加接种量可促进产气量的增加。 10、浒苔与牛粪比例为4:2（w/w）是浒苔与牛粪联合厌氧消化的最佳比例，此时产气时间为33天，总产气量最高达到6785 mL。 11、在浒苔与牛粪联合厌氧消化中，增加接种量到7.5 g（干重）时发酵周期为38天，总产气量为7470 mL，TS产气量为155.6 mL/gTS，接种量为10.5 g（干重）时发酵周期也为38天，总产气量为7020 mL，TS产气量为137.6 mL/gTS，可见增加接种量可促进产气量的增加。

Size dependence of biomass spectra and abundance spectra: the optimal distributions

Based on the hypothesis of self-optimization, we derive four models of biomass spectra and abundance spectra in communities with size-dependent metabolic rates. In Models 1 and 2, the maximum diversity of population abundance in different size classes subject to the constraints of constant mean body mass and constant mean respiration rate is assumed to be the strategy for ecosystems to organize their size structure. In Models 3 and 4, the organizing strategy is defined as the maximum diversity of biomass in different size classes without constraints on mean body mass and subject to the constant mean specific respiration rate of all individuals, i.e. the average specific respiration rate over all individuals of a community or group, which characterizes the mean rate of energy consumption in a community. Models 1 and 2 generate peaked distributions of biomass spectral density whereas Model 3 generates a fiat distribution. In Model 4, the distributions of biomass spectral density and of abundance spectral density depend on the Lagrangian multipler (lambda (2)). When lambda (2) tends to zero or equals zero, the distributions of biomass spectral density and of abundance spectral density correspond to those from Model 3. When lambda (2) has a large negative value, the biomass spectrum is similar to the empirical fiat biomass spectrum organized in logarithmic size intervals. When lambda (2) > 0, the biomass spectral density increases with body mass and the distribution of abundance spectral density is an unimodal curve. (C) 2001 Elsevier Science B.V. All rights reserved.

三江源区高寒草甸退化草地植被恢复试验研究

寻求促进高寒草甸退化草地植被恢复的有效途径和方法。在高寒草甸退化严重的青海省果洛州玛沁县,研究了应用绿色植物生长调节剂（GGR 8号）、抗寒保水剂和化肥（尿素）3种不同处理对三江源区高寒草甸轻度和中度退化草地植物群落的影响。这3种处理均能显著提高轻度和中度退化草地植物群落的生物量、高度和盖度（P〈0.05）;3个处理间生物量和植物高度无显著差异（P〉0.05）。3种处理的地上生物量与对照相比,轻度和中度退化草地植物群落的生物量增幅分别达到15.0%-24.8%和10.0%-27.0%。绿色植物生长调节剂（GGR 8号）处理样地植物群落的盖度要低于其他两种处理,在中度退化草地上,这种差异达到显著水平（P〈0.05）。GGR 8号、抗寒保水剂和尿素均能促进退化草地的恢复,将其有机地结合起来,以便能更好地发挥各自的作用。

相关风险因子对高原鼠兔摄食行为的影响

研究了捕食风险环境中集群和洞口距离对高原鼠兔摄食行为的影响。结果表明 ,集群数量的增加不仅降低了警觉行为 ,同时也减少了摄食行为 ,在高风险环境中 ,集群为1时的取食行为强度最大 ,低风险环境中，为0时最大。警觉行为主要出现在距洞口 2m的范围内 ,其行为强度与洞口距离呈负相关 ,当洞口距离大于3m时，风险处理区的高原鼠兔几乎无警觉行为出现 ,且该处理区的取食区域几乎压缩在洞口旁。研究结果表明 ,在捕食风险环境中 ,高原鼠兔摄食行为与集群和洞口距离之间具有复杂的关系 ,其行为决策反映了降低风险与摄取食物间的权衡 ,行为目标是在降低捕食风险的同时尽可能地取食食物。