A characteristics study on the performance of a 2-stage light gas gun

In order to obtain an overall and systematic understanding of the performance of a two-stage light gas gun (TLGG), a numerical code to simulate the process occurring in a gun shot is advanced based on the quasi-one-dimensional unsteady equations of motion with the real gas effect,;friction and heat transfer taken into account in a characteristic formulation for both driver and propellant gas. Comparisons of projectile velocities and projectile pressures along the barrel with experimental results from JET (Joint European Tons) and with computational data got by the Lagrangian method indicate that this code can provide results with good accuracy over a wide range of gun geometry and loading conditions.

Optimization of 2-stage gas gun for fusion refueling pellet injection with consideration of real effects

Analytic expression of pellet acceleration by constant base pressure with consideration of gas-wall friction, heat transfer and viscous dissipation that important for high speed injection is obtained. The process of compression stage is formulated by a set of governing equations and can be numerically integrated. Excellent confirmation with experiments is obtained and the ways to optimum match the compression stage with the launch stage are suggested.

青藏高原东缘川西云杉林皆伐后灌木生长、繁殖与更新的研究

植物群落及其环境在干扰后的演替格局和过程的研究，是群落和生态系统动态研究的一个热点。选取青藏高原东缘山原区川西云杉林皆伐后，从草地过渡到灌丛的关键阶段的4 个皆伐迹地（恢复时间为8 a、10 a、16 a 和21 a），研究皆伐及自然恢复过程对林下典型灌木银露梅（Potentilla glabra）和唐古特忍冬（Lonicera tangutica）的生长与繁殖能力的影响以及灌木植物在迹地上的更新情况，分析灌木在不同生境中的适应对策和适应能力的差异,为揭示青藏高原东缘山原区迹地植被从草甸到灌丛演替的过程和特点及促进迹地演替与植被恢复进程提供理论依据和技术支撑。研究主要结论如下：1）皆伐后银露梅生长和繁殖能力显著提高，但对唐古特忍冬的影响不明显。皆伐后银露梅丛基径、高度和各部分生物量都显著增加（P < 0.05），但唐古特忍冬只有叶生物量和地下生物量增加，总生物量和其余构件生物量无显著变化。皆伐后，银露梅的结实数量、结实株数、不结实株数和结实株/不结实株比例显著增加（P < 0.05）。自然恢复过程中，银露梅和唐古特忍冬生长能力以及银露梅的结实量都表现出降低的趋势。随着迹地自然恢复时间的增加，银露梅和唐古特忍冬的基径、高度、丛叶片数和各部分生物量有减少的趋势。银露梅的结实株数增加, 但结实数量减少。2）皆伐对银露梅和唐古特忍冬生物量分配模式影响不一致。原始林和迹地中（除CT85）银露梅的生物量大小关系皆为：地下>茎>侧枝>叶。唐古特忍冬在原始林中的生物量大小关系为：茎＞地下部分＞侧枝＞叶,而皆伐后生物量的分配情况改变，生物量大小关系变为：地下部分＞茎＞侧枝＞叶。随着自然恢复时间的增加，银露梅减少了地下生物量的分配，而唐古特忍冬增加了地下生物量的分配。3）皆伐和恢复时间的增加改变了迹地物种组成，促使阳性乔、灌木在迹地上定居。4 个迹地上共出现了灌木15 种，乔木3 种，没有出现天然云杉和冷杉幼苗。随着恢复时间的增加，迹地上的灌木物种由原始林下的耐阴物种逐步发展为以针刺悬钩子（Rubus pungens）为主的阳性灌木。4）影响灌木幼苗密度和幼树密度的因子不一致。灌木幼苗密度与灌木层盖度显著负相关，与苔藓层盖度显著正相关。幼树密度与草本层盖度正相关，与苔藓层盖度、灌木层盖度和高度负相关。5）研究发现在青藏高原东缘山原区皆伐15～20 a 后，迹地仍以草本植物为主，推测皆伐后至少20 a 以上迹地才可能向灌丛阶段过渡，比高山峡谷地区的演替进程至少推迟了20 a。银露梅和唐古特忍冬在皆伐后自然恢复过程中表现出不同的生长与繁殖策略是由两个物种的生物学特性的差异引起的。银露梅比唐古特忍冬更适应迹地退化环境。促进青藏高原东缘山原林区迹地森林恢复一方面是尽量减少人为活动的破坏，另一方面，可以通过在迹地中播种适当的乡土乔、灌木种子（如白桦、银露梅）等人工措施，以加快演替进程。The succession pattern and process of plant community and their environments is a hot spotin community and ecosystem dynamic study. Four clearcuts were chosen in Rangtang(recovery time of 8 a、10 a、16 a and 21 a), which represented the key stage of thecommunity evolved from grass stage to shrub stage in the eastern margin of theQinghai-Tibetan Plateau. The growth and reproduction of the Potentilla glabra andLonicera tangutica and the natural regeneration of shrub plants in the primary Piceabalfouriana forest and 4 clearcuts were studied to explore how clear cutting andnatural recovery process affected the understory shrub species during the 21 years inthe eastern margin of the Qinghai-Tibetan Plateau. The main results were below.1) The growth and reproduction of P. glabra significantly increased after forestclear cutting.. But it was not so significant as to the L. tangutica. The organismbiomass and total biomass of P. glabra were increased obviously after clear cutting（P< 0.05）. But only leaves and underground biomass of L. tangutica increasedsignificantly after clear cutting（P < 0.05）. The number of fruit and growth of P. glabraincreased significantly after clear cutting too（P < 0.05）. The ramet height, basaldiameter , organism biomass and friut number of P. glabra and L. tangutica reducedas the increase of recovery time.2) The biomass allocation patterns varied between P. glabra and L. tangutica inthe primary forest and clearcuts. The biomass allocation of P. glabra both in primary forest and clearcuts was followed as: underground part > stem > branch > leaves.However, the biomass allocation of L. tangutica had changed after the clear cutting.The biomass allocation of L. tangutica in the primary forest was followed as: stem >underground part > branch > leaves and it was underground part > stem > branch >leave in clearcuts. The biomass allocation of P. glabra and L. tangutica varied amongclearcuts. Aboveground biomass was increased while underground biomass decreasedfor P. glabra with the increase of recovery period. However, the L. tangutica showedthe reverse changing pattern.3) Clear cutting and recovery time had changed the species composition of theclearcuts. There were 15.shruby species and 3 tree species in the four clearcuts. Nospruce and fir seedlings were found. In the early stage after clear cutting, there wereonly understory shrub species from the primary Picea balfouriana forest. The sunnyspecies, especieally Rubus pungens invaded intensly as the increase of recovery time.4) There was a significant negative relationship between density of seedlingswith shrub layer coverage and positive correlation with moss coverage. The saplingshad significantly positive correlation with herb layer coverage and negativecorrelation with moss coverage, shrub layer coverage and height.5）Comparing to studies in Miyalou, a nearby high mountain and canyon area,the secondary sucession in this subalpine plateau areas lagged at least 20 years.P. glabra and L. tangutica showed different growth and reproduction strategies toclear cutting and natural recovery , which may associated with the difference of theirbiological characters. P. glabra was more adaptive to the clear cutting than the L.tangutica. Two suggestions were probably recommended to promote the recoveryprogress in the subalpine plateau areas based on the results of this study. Limitanthropogenic disturbance, and meanwhile sow native tree and shrub seeds inclearcuts.

A COMPARATIVE-STUDY OF KARYOTYPES OF MUNTJACS BY CHROMOSOME PAINTING

We have used a combination of chromosome sorting, degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR), chromosome painting and digital image capturing and processing techniques for comparative chromosome analysis of members of the genus Muntiacus. Chromosome-specific ''paints'' from a female Indian muntjac were hybridised to the metaphase chromosomes of the Gongshan, Black, and Chinese muntjac by both single and three colour chromosome painting. Karyotypes and idiograms for the Indian, Gongshan, Black and Chinese muntjac were constructed, based on enhanced 4', 6-diamidino-2-phenylindole (DAPI) banding patterns. The hybridisation signal for each paint was assigned to specific bands or chromosomes for all of the above muntjac species. The interspecific chromosomal homology was demonstrated by the use of both enhanced DAPI banding and comparative chromosome painting. These results provide direct molecular cytogenetic evidence for the tandem fusion theory of the chromosome evolution of muntjac species.

瞄准国际软件科技前沿走自主创新之路--不断开拓进取的软件研究所

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Breeding behavior under temporal risk of predation in male root voles (Microtus oeconomus)

We examined breeding behavior responses of male root votes (Microtus oeconomus) to temporal risk of predation by using acute and chronic exposure to predator odor. The 2 series of exposure experiments provided 2 types of temporal patterns of risk: continuous safety with a brief period of risk and Sustained risk with a brief period of safety. Male root votes that were acutely exposed to predator odor for I h suppressed their breeding behavior, but bred immediately after exposure to control odor for I h. Those chronically exposed to predator odor for 20 days maintained behavioral suppression during the 1-h period of exposure to control odor. Acutely exposed males did not change their physiological patterns of breeding, but those chronically exposed to predator odor had reduced testosterone concentration and epididymis index. Our results indicate that breeding behavior in a given situation depends on the overall patterns of risk experienced by male root votes, and the acute and chronic stress responses that affect reproduction are responsible for different behavioral responses to the 2 types of temporal patterns of risk. We also discuss the reasons for conflicting results about breeding suppression of votes between previous studies in the laboratory and the field.

Transient flow patterns and bubble slug lengths in parallel microchannels with oxygen gas bubbles produced by catalytic chemical reactions

Transient flow patterns and bubble slug lengths were investigated with oxygen gas (O-2) bubbles produced by catalytic chemical reactions using a high speed camera bonded with a microscope. The microreactor consists of an inlet liquid plenum, nine parallel rectangular microchannels followed by a micronozzle, using the MEMS fabrication technique. The etched surface was deposited by the thin platinum film, which is acted as the catalyst. Experiments were performed with the inlet mass concentration of the hydrogen peroxide from 50% to 90% and the pressure drop across the silicon chip from 2.5 to 20.0 kPa. The silicon chip is directly exposed in the environment thus the heat released via the catalytic chemical reactions is dissipated into the environment and the experiment was performed at the room temperature level. It is found that the two-phase flow with the catalytic chemical reactions display the cyclic behavior. A full cycle consists of a short fresh liquid refilling stage, a liquid decomposition stage followed by the bubble slug flow stage. At the beginning of the bubble slug flow stage, the liquid slug number reaches maximum, while at the end of the bubble slug flow stage the liquid slugs are quickly flushed out of the microchannels. Two or three large bubbles are observed in the inlet liquid plenum, affecting the two-phase distributions in microchannels. The bubble slug lengths, cycle periods as well as the mass flow rates are analyzed with different mass concentrations of hydrogen peroxide and pressure drops. The bubble slug length is helpful for the selection of the future microreactor length ensuring the complete hydrogen peroxide decomposition. Future studies on the temperature effect on the transient two-phase flow with chemical reactions are recommended.

Reducing H2S production by O-2 feedback control during large-scale sewage sludge composting

Hydrogen sulfide (H2S) production patterns and the influence of oxygen (O-2) concentration were studied based on a well operated composting plant. A real-time, online multi-gas detection system was applied to monitor the concentrations of H2S and O-2 in the pile during composting. The results indicate that H2S was mainly produced during the early stage of composting, especially during the first 40 h. Lack of available O-2 was the main reason for H2S production. Maintaining the O-2 concentration higher than 14% in the pile could reduce H2S production. This study suggests that shortening the interval between aeration or aerating continuously to maintain a high O-2 concentration in the pile was an effective strategy for restraining H2S production in sewage sludge composting. (C) 2010 Elsevier Ltd. All rights reserved.

Electrospray ionization multiple-stage tandem mass spectrometric analysis of diglycosyldiacylglycerol glycolipids from the bacteria Bacillus pumilus

Electrospray ionization (ESI) combined with multiple-stage tandem mass spectrometry (MSn) was used to directly analyze the glycolipid mixture from bacteria Bacillus pumilus without preliminary separation. Full scan ESI-MS revealed the composition of picomole quantities of glycerolglycolipid species containing C-14-C-19 fatty acids, some of which were monounsaturated, Two main components were identified from their molecular masses and fragmentation pathways. The fragmentation pathway of the known compound compared with the investigated compound verified the proposed structure as 1(3)-acyl-2-pentadecanoyl-3(1)-O-[beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl]-sn-glycerols. A comparison of the multiple tandem mass spectra of the different alkali-metal cation adducts indicates that the intensity of fragments and the dissociation pathways are dependent on the alkali-metal type, The basic structures of glycerolglycolipids were reflected clearly from the fragmentation patterns of the sodium cations, The intense fragments of the sugar residue from the precursor ions were obtained from the lithiated adduct ions. ESI-MSn spectra of [M + K](+) ions did not provide as much fragmentation as [M + Na](+) and [M + Li](+) adducts, but their spectra allow the position of glycerol acylation to be determined. On the basis of MS2 spectra of[M + K](+) ions, it was established that all components have a C-15:0 fatty acid at the sn-2 position of the glycerol backbone and C-14-C-19 acids at the sn-1 position of the glycerol backbone. Copyright (C) 1999 John Wiley & Sons, Ltd.

Three-stage transformation of chlorophyll transient fluorescence pattern under sustained dehydration and the discovery of critical water content in seaweeds

The chlorophyll fluorescence kinetics of marine red alga Grateloupia turutunt Yamada, green alga Ulva pertusa Kjellm and brown alga Laminaria japonica Aresch during natural sustained dehydration were monitored and investigated. The pulse amplified modulation (PAM) system was used to analyze the distinct fluorescence parameters during thallus dehydration. Results proved that the fluorescence kinetics of different seaweed all showed three patterns of transformation with sustained water loss. These were: 1) peak kinetic pattern (at the early stage of dehydration fluorescence enhanced and quenched subsequently, representing a normal physiological state). 2) plateau kinetic pattern (with sustained water loss fluorescence enhanced continuously but quenching became slower, finally reaching its maximum). 3) Platform kinetic pattern (fluorescence fell and the shape of kinetic curve was similar to plateau kinetic pattern). A critical water content (CWC) could be found and defined as the percentage of water content just prior to the fluorescence drop and to be a significant physiological index for evaluation of plant drought tolerance. Once thallus water content became lower than this value the normal peak pattern can not be recovered even through rehydration, indicating an irreversible damage to the thylakoid membrane. The CWC value corresponding to different marine species were varied and negatively correlated with their desiccation tolerance, for example. Laminaria japonica had the highest CWC value (around 90%) and the lowest dehydration tolerance of the three. In addition, a fluorescence "burst" was found only in red algae during rehydration. The different fluorescence parameters F-o, F-v and F-v, F-m were measured and compared during water loss. Both F-o and F-v increased in the first stage of dehydration but F-v/F-m. kept almost constant. So the immediate response of in vivo chlorophyll fluorescence to dehydration was an enhancement. Later with sustained dehydration F-o increased continuously while F-v decreased and tended to become smaller and smaller. The major changes in fluorescence (including fluorescence drop during dehydration and the burst during rehydration) were all attributed to the change in F-o instead of F-v This significance of F-o indicates that it is necessary to do more research on F-o as well as on its relationship with the state of thylakoid membrane.

Molecular structure and expression patterns of flounder (Paralichthys olivaceus) Myf-5, a myogenic regulatory factor

Myf-5, a member of the myogenic regulatory factors (MRF), has been shown to be expressed in muscle precursors in early stage zebrafish embryos. The MRFs, including MyoD, Myf-5, Myogenin and MR-F4, belong to the basic Helix-Loop-Helix transcription factors that contain a conserved basic Helix-Loop-Helix (bHLH) domain. To better understand the role of Myf-5 in the development of fish muscles, we have isolated the Myf-5 genomic sequence and cDNA from Flounder (Paralichthys olivaceus), and analyzed its structures and patterns of expression. Promoter analysis identified several putative transcription factor binding sites such as an E-box, NF-Y sites that might confer muscle-specific expression. Myf-5 transcripts were first detected in the paraxial mesoderm that gives rise to slow muscles. During somitogenesis, Myf-5 expression was found in developing somites. Myf-5 expression decreased gradually in somites in the anterior region, but remained strong in the newly formed somites. In the hatching stage, the expression was also detected in other muscle cells such as head muscle and fin muscle. In the growing fish, RT-PCR results showed that Myf-5 was expressed in the skeletal muscle and intestine. (c) 2006 Elsevier Inc. All rights reserved.

Characterization of muscle-regulatory gene, MyoD, from flounder (Paralichthys olivaceus) and analysis of its expression patterns during embryogenesis

Specification and differentiation of skeletal muscle cells are driven by the activity of genes encoding members of the myogenic regulatory factors (MRFs). In vertebrates, the MRF family includes MyoD, Myf5, myogenin, and MRF4. The MRFs are capable of converting a variety of nonmuscle cells into myoblasts and myotubes. To better understand their roles in fish muscle development, we isolated the MyoD gene from flounder (Paralichthys olivaceus) and analyzed its structure and patterns of expression. Sequence analysis showed that flounder MyoD shared a structure similar to that of vertebrate MRFs with three exons and two introns, and its protein contained a highly conserved basic helix-loop-helix domain (bHLH). Comparison of sequences revealed that flounder MyoD was highly conserved with other fish MyoD genes. Sequence alignment and phylogenetic analysis indicated that flounder MyoD, seabream (Sparus aurata) MyoD1, takifugu (Takifugu rubripes) MyoD, and tilapia (Oreochromis aureus) MyoD were more likely to be homologous genes. Flounder MyoD expression was first detected as two rows of presomitic cells in the segmental plate. From somitogenesis, MyoD transcripts were present in the adaxial cells that give rise to slow muscles and the lateral somitic cells that give rise to fast muscles. After 30 somites formed, MyoD expression decreased in the somites except the caudal somites, coincident with somite maturation. In the hatching stage, MyoD was expressed in other muscle cells and caudal somites. It was detected only in muscle in the growing fish.

南襄盆地泌阳凹陷断裂斜坡带构造特征与油气成藏

The faulted slope zone of Biyang depression, a multiple hydrocarbon accumulation zone lying in a rich oil depression of Nanxiang basin, is a structural-sedimentary compounded slope, which is developed in Yanshanian period and has an area of 500 km2. From the ‘bottom up’, the developed strata may be divided into Yuhuangding formation in Neogene, Dacang Fang, Hetao-yuan plus Liaozhuang formations and Fenghuangzheng plus Pingyuan formation in Neogene, while Hetao-yuan formation is the main hydrocarbon-bearing target. Because of transtensional stress fields formed by persistent action of large-scale faulting in the south of the depression, sedimentary differential compaction in different stages, and tectonic inversion in later developing stage of the depression, a series of nose structure zones cut by different strike faults are developed. Therefore, the reservoir migration and accumulation are controlled by the complex faulted-nose structural zone, reservoir types are dominated by faulted-noses, faulted-blocks and fault-lithology, while lithology and stratigraphic unconformable reservoirs are locally developed. In combination with demands of practical production, applying with a new research approach of systematology and a combination with dynamic and static modes, guided by modern petroleum geologic theory, and based on previous data and studies, new techniques, methods of geophysical exploration, various computer simulation and forecasting techniques are applied in the new research of this paper. Starting from the structural features and formation mechanism, the forming mechanism of faulted structure, conditions and controlling factors of hydrocarbon accumulation, as well as various space-time allocation relationships in the process of accumulation are analyzed in the research. Besides that, the hydrocarbon migration, accumulation mechanism and dynamic evolution process are also discussed in the paper. Through the research, the accumulation rule of the faulted slope zone in faulted lake basin, the distribution and enrichment regularity of different reservoir controlling factors are systematically summarized. The summarizations indicate that the faulted slope is a favorable orientational zone, hydrocarbon is accumulated in nose structures and enriched in the main body of nose structures, faulted transformation zone and the ascent direction of laddering faulted blocks, the faults are the controlling factors, hydrocarbon accumulation zones controlled by fault-lithology are distributed along the faulting direcion. In the end, hydrocarbon migration and accumulation models of complex faulted-nose blocks are established. 1) Down cut model—‘flank-sheet’: the hydrocarbon is migrated like ‘sheet’ along a series of faults with parallel distribution and accumulated in the flank of nose structures; 2）Cross cut --‘axis-string’ model: the hydrocarbon cutting across the faults is migrated like ‘string’ and accumulated in the axis of nose structures. In view of different distribution models, reservoir forming combination patterns are divided and hydrocarbon reservoir evaluation exploration is carried out, which achieves good results in application. Key words: faulted slope zone; migration and accumulation model; reservoir controlling mechanism; reservoir-forming combination