用于钕玻璃啁啾脉冲放大系统光谱整形的多层介质膜反射镜

在千焦拍瓦高功率啁啾脉冲放大系统设计中,为了尽量消除增益窄化和增益饱和效应的影响,同时尽可能提高高功率激光输出脉冲信噪比参数,激光脉冲时空和光谱的整形问题备受关注.提出一种光谱整形新方法,利用特定结构的多层介质膜反射镜,可实现对大能量高功率啁啾脉冲钕玻璃放大系统中啁啾脉冲的光谱整形.研究结果表明,只要合理选择多层介质膜系的结构参数,可有效地控制其反射率分布,且在保证反射相位基本不变的条件下其调制度可超过60%.针对钕玻璃1053nm波长设计而成的光谱整形反射镜,反射带宽可达到196nm,色分辨率约为0.1nm,在几十纳米波长范围所对应的相位偏差小于12mrad,相当于λ/524,能够满足"神光Ⅱ"千焦拍瓦改造的技术指标要求.

低损耗193nm反射膜的设计

采用1/4规整膜系,从电场强度、吸收损耗及散射损耗的分布几个方面,对影响193 nm反射膜性能的因素进行了分析。以分析结果为基础,对低损耗193 nm反射膜的设计进行了探讨。结果表明:在空气侧的外膜层中电场强度较大,随着层数向内过渡,电场强度迅速减小;高折射率材料膜层的吸收损耗明显高于低折射率材料膜层的吸收损耗,而且靠近空气侧最外层的高折射率膜层的吸收损耗最大;按由外层向内层过渡的方向,吸收损耗迅速减小,减小的速度与高低折射率材料折射率的比值相关;表面散射损耗与两种材料的折射率比值成正比,但折射率比值减小后只能通过增加膜层数来获得一定的反射率,而这样又会使表面粗糙度增加,并且引入其它的损耗。因此,选择折射率差值适当大一些的材料对降低散射损耗是有利的。设计了27层膜堆的193 nm反射膜,设计反射率在98%以上。

Comparison of echogram measurements against data expectations and assumptions for distinguishing seafloor substrates

Defining types of seafloor substrate and relating them to the distribution of fish and invertebrates is an important but difficult goal. An examination of the processing steps of a commercial acoustics analyzing software program, as well as the data values produced by the proprietary first echo measurements, revealed potential benef its and drawbacks for distinguishing acoustically distinct seafloor substrates. The positive aspects were convenient processing steps such as gain adjustment, accurate bottom picking, ease of bad data exclusion, and the ability to average across successive pings in order to increase the signal-to-noise ratio. A noteworthy drawback with the processing was the potential for accidental inclusion of a second echo as if it were part of the first echo. Detailed examination of the echogram measurements quantified the amount of collinearity, revealed the lack of standardization (subtraction of mean, division by standard deviation) before principal components analysis (PCA), and showed correlations of individual echogram measurements with depth and seafloor slope. Despite the facility of the software, these previously unknown processing pitfalls and echogram measurement characteristics may have created data artifacts that generated user-derived substrate classifications, rather than actual seafloor substrate types.

Comparação entre o Complexo Juiz de fora e a Unidade Granulítica Ponte de Zinco: geocronologia U-Pb em zircão (LA-ICPMS), geoquímica isotópica e composição das fontes geradoras

A comparação entre o Complexo Juiz de Fora e a Unidade Granulítica Ponte de Zinco (Mangaratiba - RJ) revelou que existem diferenças significativas entre essas unidades. Na Unidade Granulítica Ponte de Zinco, são encontrados ortogranulitos de composição granítica e granodiorítica, que representam o embasamento da Unidade, denominada aqui de Ortogranulitos Ribeirão das Lajes. Dois outros litotipos ortoderivados também foram encontrados: (i) um ortognaisse com granada (MAN-JEF-03a), sendo que a granada ocorre de forma subordinada; (ii) ortognaisse leucocrático (MAN-JEF-04), com características miloníticas. Além dessas, rochas metassedimentares também afloram na Unidade Granulítica Ponte de Zinco. Foi interpretado que um ortogranulito (MAN-JEF-01a) de alto-K, com composição monzogranítica, cristalizou em ca. 2653 37 Ma (U-Pb em zircão por LA-ICPMS), afetado por um evento no Neoproterozóico, que gerou os minerais máficos hidratados, observados na análise petrográfica e como mostram as borda de sobrecrescimento em zircão. Sua idade modelo de Nd de 2,7 Ga e seu εNd positivo de +2,1, apontam para uma gênese mantélica, tendo assimilado rochas crustais, pois são encontrados grãos de zircão herdados de aproximadamente 2996 17 Ma e 3343 3.8 Ma. Os dados de litogeoquímica e sua razão 87Sr/86 Sr(t) (0,70529), são compatíveis com uma geração em um arco continental. O ortognaisses com granada do ponto MAN-JEF-03 possui composição granodiorítica. A idade de cristalização interpretada pela análise geocronológica U-Pb em zircão (LA-ICPMS), foi ca. 2117 15 Ma. Esse litotipo foi metamorfizado no Neoproterozóico, sendo a idade obtida pelo intercepto inferior de 631 40 Ma. Seus dados isotópicos apontam para uma rocha juvenil gerada a partir do manto (TDM ≈ de 2,1 Ga e εNd = +3,4). Sua alta razão 87Sr/86 Sr(t) (0,710 ) juntamente com os grãos de zircão herdados (2,6 Ga) e a presença de enclaves, indicam assimilação de rochas crustais. O ortognaisse leucocrático (MAN-JEF-04) classificado como alto-K, possui composição monzogranítica, idade 2132 9,4 Ma U-Pb em zircão (LA-ICPMS). Um único grão relíquiar de ortopiroxênio encontrado em lâmina, , indica que a rocha já foi submetida a metamorfismo de fácies granulito, porém esse evento não deixou registro nos grãos analisados. O retrometamorfismo pode ter ocorrido em dois momentos, 647 11 Ma e 595 38 Ma, calculados através da concordia age, em sobrecrescimentos homogêneos e, pelo intercepto inferior, respectivamente. Sua baixa razão 87Sr/86 Sr(t) (≈ 0,703) associada com εNd positivo (+2,3) e sua idade modelo de aproximadamente 2,1 Ga, revelam que a rocha foi formada por um material mantélico juvenil. Já as análises geocronológicas em U-Pb em zircão (LA-ICPMS) na região de Juiz de Fora (MG), revelaram a existência de dois litotipos Arqueanos: um ortogranulito granodiorítico (MB-JEF-01b), de baixo-K com idade de 2849 11 Ma e com herança de 2975 10 Ma. Seu εNd positivo (+5,9) aponta para uma gênese a partir do manto depletado, já sua alta razão 87Sr/86Sr(t) (≈0,709) indica contaminação de Rb de fontes externas, talvez causada pela assimilação da crosta, como revelam os zircões herdados e/ou fluidos retrometamorficos. Outro litotipo é uma rocha gabróica do tipo E-MORB, cuja idade foi calculada em 2691 14 Ma, com retrometamorfismo ocorrido no intervalo de 604 67 Ma, obtida pelo intercepto inferior. Seu εNd igual a +3,4 e sua razão 87Sr/86 Sr(t) (≈0,701) mostram extração a partir do manto depletado. Novos dados isotópicos do CJF na região de Três Rios (RJ) e Juiz de Fora (MG), sugerem que os ortogranulitos calcioalcalinos podem representar grupos distintos. Rochas com εNd positivos são consequentemente associadas ao manto depletado, porém rochas com εNd negativos devem ter sido geradas por fusão crustal, que podem ser fusão de crosta inferior, devido a razão 87Sr/86 Sr(t) (0,70514) encontrada no amostra MB-JEF-02a (ortogranulito de alto-K) ou tendo a crosta contribuição nas gênese dessas rochas. Os ortogranulitos básicos possuem εNd positivos com baixas razões 87Sr/86 Sr(t) , o que indica extração a partir do manto depletado, porém sua razões La/YbN e La/NbN maiores que 1, revelam alguma contribuição de uma fonte enriquecida, assim também mostram suas razões Pb/Pb, que são maiores do que as razões calculadas para evolução de Pb na Terra. Essas interpretações ainda podem ser estendidas para um ortoanfibolito da série alcalina, encontrado na região de Três Rios (RJ).

Wassergehalte tiefgefrorener Kammmuscheln

Kurzfassung Der Handel mit tiefgefrorenen Kammmuscheln (Pectinidae) hat in den letzten Jahren deutlich zugenommen und ist von der Jakobsmuschel (Pecten maximus) auf eine Reihe weiterer Spezies erweitert worden. Neben nicht zutreffender Handelsbezeichnung fällt diese Erzeugnisgruppe immer wieder durch einen erhöhten Wasserzusatz negativ auf. Es wurde die Zusammensetzung des Muskelfleisches von Produkten aus dem deutschen Handel bestimmt und das Wasser zu Protein- Verhältnis (W/P) berechnet. Eine erhebliche Zahl von Proben hatte hohe Wassergehalte und ein W/P Verhältnis > 5. Dies betraf insbesondere die Tiefseescallop (Placopecten magellanicus) und die Japanische Kammmuschel (Mizuhopecten yessoensis). In den meisten Fällen wurden Zusatzstoffe nachgewiesen, obwohl die gesetzlich vorgeschriebene Deklaration fehlte. Abstract The market share of quick-frozen scallops (Pectinidae) has increased significantly in recent years and has been extended besides the king scallop (Pecten maximus) to a variety of other species. Apart from an incorrect labeling this product group stands out for often excessively high water addition. The composition of the muscle meat and the water to protein ratio (W/P) was determined in samples from the German retail. The results showed that a considerable number of samples had very high moisture contents and W/P ratios > 5. These facts were mainly true for Placopecten magellanicus and Mizuhopecten yessoensis. There was no conformity with the prescribed declaration of food additives.

Surface-stress-induced Mott transition and nature of associated spatial phase transition in single crystalline VO2 nanowires.

We demonstrate that the Mott metal-insulator transition (MIT) in single crystalline VO(2) nanowires is strongly mediated by surface stress as a consequence of the high surface area to volume ratio of individual nanowires. Further, we show that the stress-induced antiferromagnetic Mott insulating phase is critical in controlling the spatial extent and distribution of the insulating monoclinic and metallic rutile phases as well as the electrical characteristics of the Mott transition. This affords an understanding of the relationship between the structural phase transition and the Mott MIT.

Seasonal growth of King George whiting (Sillaginodes punctata) estimated from length-at-age samples of the legal-size harvest

Samples of 11,000 King George whiting (Sillaginodes punctata) from the South Australian commercial and recreational catch, supplemented by research samples, were aged from otoliths. Samples were analyzed from three coastal regions and by sex. Most sampling was undertaken at fish processing plants, from which only fish longer than the legal minimum length were obtained. A left-truncated normal distribution of lengths at monthly age was therefore employed as model likelihood. Mean length-at-monthly-age was described by a generalized von Bertalanffy formula with sinusoidal seasonality. Likelihood standard deviation was modeled to vary allometrically with mean length. A range of related formulas (with 6 to 8 parameters) for seasonal mean length at age were compared. In addition to likelihood ratio tests of relative fit, model selection criteria were a minimum occurrence of high uncertainties (>20% SE), of high correlations (>0.9, >0.95, and >0.99) and of parameter estimates at their biological limits, and we sought a model with a minimum number of parameters. A generalized von Bertalanffy formula with t0 fixed at 0 was chosen. The truncated likelihood alleviated the overestimation bias of mean length at age that would otherwise accrue from catch samples being restricted to legal sizes.

农牧交错区不同植物群落的根冠比特征及土壤呼吸日动态的观测研究

本论文对草地群落地上/地下生物量构成、根冠比特征及其影响因子以及土壤呼吸测定方法比较等的国内外研究进展和主要成果进行了综述，在此基础之上对地处我国北方农牧交错带中段的内蒙古多伦县境内的18种草地群落（包括天然草地和人工草地群落）进行了相关内容的研究工作。 在2002年生长季期间，对这18个植物群落中选取的16个进行了群落学调查，测定了其地上、地下生物量，同时测定了土壤含水量、土壤容重、土壤全氮含量和土壤有机质含量。分别分析了地上、地下生物量以及根冠比（root to shoot ratio）与这些立地因子间的相关关系。同期，从18个群落中选定10个代表性群落测定其土壤呼吸速率，测定方法选用了动态红外气体分析法 (Infra red gas analysis， abbreviated as IRGA)和碱液吸收法（Alkali absorption, abbreviated as AA）。对这两种方法的测定结果进行了比较分析，同时分析了不同群落间土壤呼吸变化与土壤水分和养分状况等的相关关系。主要结论如下： ①16种植物群落的地上和地下生物量差异明显，地上生物量变化范围在80~500 g•m-2之间;相比之下，地下生物量的变化范围要大得多，16个群落中地下生物量最小的为猪毛菜群落，最大的为拂子茅群落，分别为533 g•m-2和2590 g•m-2。群落的根冠比在1.5～11.21之间，平均根冠比为 5.69。 ②土壤含水量对地上和地下生物量有着重要的影响，土壤含水量高的样地（羊草样地）较含水量低（小米蒿样地）的样地地上生物量高，反之亦然。但含水量与地下生物量之间的这种关系却不明显，即土壤含水量高的样地其地下生物量并不一定比含水量低的样地地下生物量高;根冠比与土壤含水量之间基本上呈负相关。土壤全氮含量和有机质含量与地上、地下生物量也存在着一定的正相关关系，而土壤容重却与生物量存有负相关关系;根冠比与土壤全氮、有机质和容重的关系正好与此相反，即根冠比与全氮和有机质含量呈负相关，与容重为正相关。 ③10种植物群落土壤呼吸的昼夜变化比较明显，均为单峰型曲线，主要受土壤温度的驱动，但同时也受到当日降水情况和云量、风速等气象因子的较大影响。因此，影响到这些群落土壤呼吸日动态的一致性，使得规律性并不明显。 ④用碱液吸收法和动态密闭气室法测定的10个群落的土壤呼吸速率变化范围分别为394~894mg C•m-2•d-1和313~2043 mg C•m-2•d-1，其中碱液吸收法测定结果平均为动态气室法的67.5%，明显低于动态密闭气室法。 ⑤两种测定方法具有很好的相关性，R2为0.8739。本研究中发现，在土壤呼吸速率低的情况下，两种方法的测定结果十分接近，甚至碱液吸收法的测定结果稍大于动态密闭气室法;而在土壤呼吸速率较高的情况下，动态密闭气室法测定结果则显著高于碱液吸收法。上述结果与国内外同类研究的结果高度一致，从而为校正我们以往采用碱液吸收法在该区域的测定结果提供了可靠依据。 ⑥各个群落间的土壤呼吸变化与立地土壤水分和土壤养分之间存有一定的相关关系，但并不显著，可能与这些群落土壤呼吸测定不是在同一天进行有关。

Ice storage characteristics of cultured silver carp

Cultured silver carp (Hypopthalmichthys molitrix 800-1000 g) was stored in ice (fish to ice ratio 1:1) in a plywood box insulated with one inch thick expanded polystyrene and subjected to detailed examination of quality by chemical, microbiological and organoleptic evaluation at regular intervals to assess the storage life in good acceptable form. Alpha-amino nitrogen, non-protein nitrogen and pH values showed no positive correlation as spoilage index. Total volatile base nitrogen was not high at the end of the storage period although the fish became unacceptable during the period. There was steep decrease in total bacterial count during initial stages of storage and then increased steadily on further storage. Organoleptic evaluation of raw and cooked meat revealed that fish was in good acceptable form up to 14 days in ice.

桃不同组织中的葡萄糖/果糖比值特点及己糖代谢

以不同葡萄糖/果糖（G/F）类型的桃品种（正常G/F 品种：‘燕红’、‘冈山白’和‘山一白桃’；高G/F 品种：‘龙124’、‘龙246’、‘张黄7 号’和‘临白7 号’）为试材，测定果实发育期果实、叶片、韧皮部和木质部中糖和淀粉含量，并分别在果实第一迅速生长期、硬核期和成熟期测定了‘燕红’、‘山一白桃’、‘龙124’、‘龙 246’和‘临白7号’果实和叶片中己糖相关酶。研究不同G/F类型桃品种产生G/F差异的组织器官和时期，并且分析相关代谢酶调控机理。 两类不同G/F 桃果实中均以蔗糖作为主要碳水化合物积累形式，花后70 d前蔗糖含量很低，随后快速积累直至果实成熟；山梨醇含量较为稳定，高G/F品种‘龙124’两年间在未成熟果实中山梨醇含量高于正常 G/F品种；葡萄糖和果糖含量在果实第一迅速生长期积累，之后逐渐降低。高 G/F 品种‘龙124’和‘临白7号’成熟果实中葡萄糖含量高于‘龙246’和正常 G/F 品种。正常G/F品种果实、叶片、韧皮部和木质部中葡萄糖和果糖含量基本相等，G/F基本保持在0.7-1.5。高G/F品种果实、叶片中葡萄糖显著高于果糖，果实中G/F在1.6-8.8，叶片中G/F在果实未成熟时为2.5-9.3，在果实成熟期为14.5-21.3。然而韧皮部和木质部中葡萄糖略高于果糖或基本相等，但较正常G/F品种高。因此，光合产物在韧皮部的运输对桃果实的G/F 没有显著影响。 在第一迅速生长期和成熟期时，所有供试桃品种果实和叶片中合成己糖的NAD+-SDH 和 SOX较为活跃，而分解己糖的FRK、GLK和PGI则保持在较低水平；在果核硬化期则相反，果实和叶片中合成己糖的NAD+-SDH 和 SOX活性较低，而分解己糖的FRK、GLK和PGI则较为活跃。高G/F品种‘龙124’和‘龙246’在果核硬化期果实中的FRK、NADP+-SDH 和GLK活性显著高于正常G/F品种，而高G/F品种‘临白7号’则与正常G/F品种没有明显差异。可见，高G/F品种间己糖代谢调控机制也有所差异。此外，叶片中两种G/F类型间的己糖代谢相关酶差异并无明显规律，由此我们认为叶片存在与果实类似但相对独立的调控机制。

A new, fast response CO2 sensor

The inability of emissions reduction methods to meet upcoming legislation without an unacceptable increase in vehicle cost is a major problem of automobile manufacturer. This work aims to develop a cost-effective reduction of automobile emissions. A prototype CO2 sensor with 5 msec response time was built and bench tested, then used on an engine. The sensor design was based on standard emissions measurement technology using non-dispersive IR absorption. An improved sensor has now been completed with significant improvements in terms of signal to noise ratio and long-term stability. The improved sensor will be used to measure CO2 concentrations on three different engines. The results will then be used to validate engine and catalyst models and to propose control strategies aimed at reducing overall emissions. A brief description of the sensor itself was presented. Original is an abstract.

Maturity, spawning and fecundity of Saurida tumbil (Bloch, 1795) from Mumbai waters

The absolute fecundity of Saurida tumbil ranged between 24160 to 172000 eggs with weight range of 230-670 g. Linear relationship between fecundity and weight was more valid than that of length and ovary weight. The fish breed once a year during November to March. The length at which 50% of the females mature was calculated as 296 mm. The female dominated the commercial catch and overall male to female ratio of population was 1:1.62 throughout the year.

Transportation of fish - 1. A preliminary study on insulated containers and their efficacy in long distance transportation

Polythene lined thermocole insulated plywood boxes (second-hand tea chests) could be successfully used for transport of fresh iced fish. It was found that a minimum of 25 mm thermocole insulation was necessary during summer (April to June) and 15 mm during winter (Nov. to March). By using these insulated boxes the initial fish to ice ratio could be brought down to 1:0.75 and still further to 1:0.5 at the height of winter in Jan. and Feb. These second-hand tea chests are robust and are able to stand a minimum of 5 trips to and fro. The moulded polystyrene boxes are not suited for long distance transport. Another redeeming feature in the entire operation was that there was practically no loss of fish due to spoilage in transit. 100% of the fish transported was in acceptable condition and could be marketed. In the non-insulated boxes used by the trade, the loss due to spoilage ranged from 10% to 25%, and this could be completely eliminated by the use of these insulated boxes.

Study on shelf life of fish cake prepared from surimi of silver carp (Hypophthalmichthys molitrix) during frozen storage

Surimi was prepared from silver carp with an aim to put this underutilized fish for profitable use. The mince prepared was washed twice with chilled water (5°C) using mince to water ratio (w/v) of 1:2 for 5-6 minutes each. After final dewatering to moisture content to about 80%; half the quantity of washed minced meat was mixed with cryoprotectants (4% sorbitol, 4% sucrose and 0.3% sodium tripolyphosphate) to produce surimi. The prepared surimi and the dewatered minced meat were packed in LDPE bags, frozen using a plate freezer and stored at -20°C. Surimi and dewatered minced meat from frozen storage were used as base material for production of fish cakes. These were fried at 160°C for 3 to 4 minutes before serving for organoleptic test. Changes in salt soluble nitrogen, total volatile base nitrogen, non-protein nitrogen, peroxide value and free fatty acid of surimi and dewatered mince were estimated at every ten days interval during the storage period of 3 months. The study has indicated that frozen storage of surimi could be a potential method for effective utilization of silver carp. This surimi when incorporated in fish cakes yielded products which retained the shelf life even up to 90 days of storage.

Standardization of setting temperature and time for fish meat

Meat to water ratio used for washing was 1:3 for oil sardine and mackerel; but for pink perch and croaker, it was 1:2. Again the washing process was repeated three times for oil sardine and mackerel; but two times for pink perch and croaker. The washed meat was mixed with 2.5% NaC1 and set at +5°C and +40°C for 1, 2 and 3hrs. The gel strength and expressible water content was measured. Basing on this study, setting temperature at +40°C was selected and with respect to time 1hr for sardine and mackerel and 3hrs for pink perch and croaker was selected.