水下拖缆稳态平衡位形的确定计算

本文建立了水下拖缆稳态平衡方程，选用前人研究的流体动力系数经验公式，讨论了平衡位形的解法，编制了平衡位形计算程序，计算了平衡位形和张力分布，提供了确定水下拖缆稳态平衡位形的计算方法。

高产抗倒伏高油玉米育种的研究

随着社会的发展,高油玉米的开发利用将给食品业和饲养业带来巨大变革,高油玉米已显得格外重要。通常高油玉米抗倒性较差,且株高和穗位高均偏高,易造成倒伏,已经给高油玉米的发展特别是新品种的推广应用造成很大障碍,同时也给农业生产带来了不必要的损失。通过育种手段,在高产高油的前提下,矮化高油玉米,降低株高及稳住高,增强其抗倒性,以适应不断发展的高品质高油玉米市场的需求。

调制型传感器信号处理的细分新技术

提出了一种基于微机时钟脉冲的新型ＦＭ—ＦＤ—ＦＭ细分原理，用于调制型传感器信号处理，可使传感器测量分辨率较采用直接细分技术时提高２～３个数量级，给出了适于实时测量与补偿的细分硬件实现方案。

Stable Isotope Technique——An Advanced Technology in Ascertaining Plant-Water Relations

Some key terms and relevant standard related with stable isotope tech- nique were introduced, and the determination of carbon, hydrogen and oxygen, the three stable isotopes in water, as well as their isotope effect was discussed. Appli- cations and advances of stable isotopes were stated mainly from plant water source, water use efficiency, the most active water adsorption region in root system and water resources utilization differences among different species in plant communi- ty. In addition, some existing problems in investigating the plant-water relations by using stable isotope technique were put forward. In this study, we aimed to promote the sustainable development of stable isotope technique in the research of plant water utilization and in the field of ecology in China.

Microsatellite Alterations on Chromosome 8 of Hepatocellular Carcinoma

Objective: To study the features of microsatellite alterations on chromosome 8 and their asso- ciation with clinicopathological characteristics of hepatocellular carcinoma (HCC). Methods: Ten highly- polymorphic microsatellite markers on chromosome 8 were selected to be detected for loss of heterozygosity (LOH), microsatellite instability (MSI) and allelic imbalance (AI) in 56 HCC using MegaBACE 500 auto- matic DNA analysis system. Results: LOH was found in 37 of 56 HCC (66.1%) on at least 1 locus, and the top three loci were D8S261(53.5%), D8S1721(52.5%) and D8S1771(52.5%). LOH frequency on D8S277 was signi?cantly higher in cases positive for serum HBsAg than in those negative for HBsAg (P <0.01). Similarly, LOH on D8S261, D8S298 and D8S1733 occurred more frequently in patients with negative HB- sAg than those with positive HBsAg (P <0.01). LOH on D8S298 and D8S1771 was more frequent in those tumors larger than 3 cm in size (P <0.05 or P <0.01). LOH frequencies of D8S1721 were signi?cantly higher in the patients with absent or not intact tumor capsule than in those with intact tumor capsule (P <0.05). LOH on D8S298 and D8S1771 was more frequently detected in tumors with intrahepatic metastasis than in those without intrahepatic metastasis (P <0.01). MSI was found in 12.5% (7/56) cases, and AI was found in 19.6% (11/56), no correlation was found between MSI and AI and clinicopathological character- istics of HCC. Conclusion: Frequent microsatellite alterations on chromosome 8 existed in HCC. LOH, which represents tumor suppressor gene pathway, plays a more important role in hepatocarcinogenesis; MSI representing mismatch repair gene pathway ranks next. LOH at a particula locus is associated with the clinicopathological parameters of human HCC.

Changes in the Activities of C4 Pathway Enzymes and Stable Carbon Isotope Discrimination in Flag Leaves of Super High-yield Hybrid Rice

Activities of several key enzymes of C-4 photosynthesis pathway and stable carbon isotope discrimination were investigated in flag leaves of a super high-yield hybrid rice (Oryza sativa L.) cv. Peiai 64S/E32 and a traditional hybrid rice cv. Shanyou 63 at different developing stages. Results show that the activity of PEP carboxylase (PEPCase) increased with age of flag leave; the activity of NADP-malate dehydrogenase (NADP-MDH) increased and reached to a peak value at grain filling stage (68-75 d after transplanting), then fell down; the activity of NADP-MDH in cv. Peiai 64S/E32 was much higher than that in cv. Shanyou 63. Before ripening stage (95 d after transplanting), NADP-malic enzyme activity rose gradually. The level of stable carbon isotope discrimination (Delta(13)C) in flag leaves and grains at different developing stages were similar and exhibited a comparative high value at ripening stage. The average Delta(13)C in leaf of cv. Peiai 64S/E32 during different developing stages was 0.43parts per thousand more than that in cv. Shanyou 63.

Food Resource Partitioning in Alpine Weasel,Steppe Polecat and Upland Buzzard:Evidence from Stable Isotope Ratios

Based on mass balance theory and IsoSource program,stable carbon and nitrogen isotopic ratios revealed that small mammals (plateau pika,root vole and plateau zokor) contributed 26.8% and 27.0% and 29.2% to alpine weasel,steppe polecat and upland buzzard of carnivores as food respectively;adult passerine birds contributed 22.3%,47.7% and 69.1%,with hatchlings contributing 50.9%,25.6% and 1.70% to each respectively.δ 13 C values plotted against δ 15 N indicated significant partitioning in two-dimensional space among the three carnivores.It was reasonable to propose a food resource partitioning among alpine weasel,steppe polecat and upland buzzard,which partially revealed their co-existence mechanisms.

Determination of Stability Constants of Cadmium-Glycine Complexes by a Unified Treatment for Potentiometric and Polarographic Data

The cadmium（Ⅱ）-glycine system was studied by the two experimental techniques, ion sensitive electrode （ISE） and differential pulse polarography （DPP）, and the experimental data obtained were used by a unified mathematical treatment to calculate the complex stability constants. The combination of the two techniques is of many advantages as ISE can be performed at low [LT]：[MT] ratios and significantly higher [MT], whereas DPP could be used well at large [LT]：[MT] ratios and much smaller [MT]. This makes it possible to study a metal-ligand system in a relatively broader range of experimental conditions that, in turn, provides more information about the metakligand system of interest. Applying the unified mathematical treatment to the cadmium-glycine system, two new complexes MHL and ML2（OH） as well as three complexes ML, ML2 and ML3, reported in literatures, could be modeled and all their stability constants have been refined.

Nuclear ?eld shift effects on stable isotope fractionation: a review

An anomalous isotope effect exists in many heavy element isotope systems （e.g., Sr, Gd, Zn, U）. This effect used to be called the ＂odd--even isotope effect＂ because the odd mass number isotopes behave differently from the even mass number isotopes. This mass-indepen- dent isotope fractionation driving force, which originates from the difference in the ground-state electronic energies caused by differences in nuclear size and shape, is cur- rently denoted as the nuclear field shift effect （NFSE）. It is found that the NFSE can drive isotope fractionation of some heavy elements （e.g., Hg, T1, U） to an astonishing degree, far more than the magnitude caused by the con- ventional mass-dependent effect （MDE）. For light ele- ments, the MDE is the dominant factor in isotope fractionation, while the NFSE is neglectable. Furthermore, the MDE and the NFSE both decrease as temperatures increase, though at different rates. The MDE decreases rapidly with a factor of 1/T2, while the NFSE decreases slowly with a factor of 1/T. As a result, even at high temperatures, the NFSE is still significant for many heavy element isotope systems. In this review paper, we begin with an introduction of the basic concept of the NSFE, including its history and recent progress, and follow with the potential implications of the inclusion of the NFSE into the kinetic isotope fractionation effect （KIE） and heavy isotope geochronology.

Starch Modifications to Improve the Paste Stabilities Both in Phase and Viscosity for Warp Sizing

An attempt has been made to improve the paste stabilities both in viscosity of a hot starch paste and in phase of a starch-polyvinyl alcohol blend paste for warp sizing. The phase stability was evaluated in terms of the initial demixing time, and the volume percentage of polyvinyl alcohol separated. It was found that starch cross-linking is harmful to the phase stability of a starch-polyvinyl alcohol blend paste no matter what a type of polyvinyl alcohol is used, although the cross-linking is an effective technique for stabilizing the viscosity of a hot starch paste. The separation rate and extent all increase with the increase in the cross-linking degree of starch. However, this defect can be eliminated through introducing quaternary ammonium groups into crosslinked starch molecules. Evident effect can be achieved when the degree of substitution is as less as 0.021. Generally, increase in the DS reduces the separation rate and extent, and thereby raising the phase stability. Moreover, the effects of both starch content and PVA type on the separation are also considered. Cationization after starch cross-linking shows improved stabilities both in viscosity and phase.

Microseismic source location using the Log-Cosh function and distant sensor-removed P-wave arrival data

Source location is the core foundation of microseismic monitoring.To date,commonly used location methods have usually been based on the ray-tracing travel-time technique,which generally adopts an L1 or L2 norm to establish the location objective function.However,the L1 norm usually achieves low location accuracy,whereas the L2 norm is easily affected by large P-wave arrival-time picking errors.In addition,traditional location methods may be affected by the initial iteration point used to find a local optimum location.Furthermore,the P-wave arrival-time data that have travelled long distances are usually poor in quality.To address these problems,this paper presents a microseismic source location method using the Log-Cosh function and distant sensor-removed P-wave arrival data.Its basic principles are as follows:First,the source location objective function is established using the Log-Cosh function.This function has the stability of the L1 norm and location accuracy of the L2 norm.Then,multiple initial points are generated randomly in the mining area,and the established Log-Cosh location objective function is used to obtain multiple corresponding location results.The average value of the 50 location points with the largest data field potential values is treated as the initial location result.Next,the P-wave travel times from the initial location result to triggered sensors are calculated,and then the P-wave arrival data with travel times exceeding 0.2 s are removed.Finally,the aforementioned location steps are repeated with the denoised P-wave arrival dataset to obtain a high-precision location result.Two synthetic events and eight blasting events from the Yongshaba mine,China,were used to test the proposed method.Regardless of whether the P-wave arrival data with long travel times were eliminated,the location error of the proposed method was smaller than that of the L1/L2 norm and trigger-time-based location method(TT1/TT2 method).Furthermore,after eliminating the Pwave arrival data with long travel distances,the location accuracy of these three location methods increased,indicating that the proposed location method has good application prospects.

Application of Stable Isotope Techniques in Studies of Carbon and Nitrogen Biogeochemical Cycles of Ecosystem

Stable isotope techniques have been proved useful as tools for studying the carbon (C) and nitrogen (N) biogeochemical cycles of ecosystem. This paper firstly introduced the basic principles and the distribution characteristics of stable isotope, then reviewed the recent advances and applications of stable isotope in the C and N biogeochemical cycles of ecosystem. By applying the 13 C natural abundance technique, ecologists are able to understand the photosynthetic path and CO 2 fixation of plants, the CO 2 exchange and C balance status of ecosystem, the composition, distribution and turnover of soil organic C and the sources of organic matter in food webs, while by using the 13 C labeled technique, the effects of elevated CO 2 on the C processes of ecosystem and the sources and fate of organic matter in ecosystem can be revealed in detail. Differently, by applying the 15 N natural abundance technique, ecologists are able to analyze the biological N 2 -fixation, the N sources of ecosystem, the N transformation processes of ecosystem and the N trophic status in food webs, while by using the 15 N labeled technique, the sources, transformation and fate of N in ecosystem and the effects of N input on the ecosystem can be investigated in depth. The applications of both C and N isotope natural abundance and labeled techniques, combined with the elemental, other isotope ( 34 S) and molecular biomarker information, will be more propitious to the investigation of C and N cycle mechanisms. Finally, this paper concluded the problems existed in current researches, and put forward the perspective of stable isotope techniques in the studies on C and N biogeochemical cycles of ecosystem in the future.

Seasonal Changes in Food Uptake by the Sea Cucumber Apostichopus japonicus in a Farm Pond: Evidence from C and N Stable Isotopes

This study investigated the seasonal changes in carbon (C) and nitrogen (N) stable isotope values of several typical food sources of Apostichopus japonicus in a farm pond, including particulate organic matter (POM), macroalgae, benthic microalgae and animals such as nematode and copepod. The stable isotope technique was used to quantify relative contributions of various sources to the food uptake by A. japonicus. The results showed that significant changes occurred in the C and N stable isotope values of sea cucumber food sources due to the seasonality of micro-or macroalgae prosperity and the fluctuation of environmental conditions. The sea cucumber A. japonicus exhibited corresponding alterations in feeding strategy in response to the changes in food conditions. Calculation with a stable isotope mixing model showed that macroalgae was the principal food source for A. japonicus throughout the 1-yr investigation, with the relative contribution averaging 28.1% - 63.2%. The relative contributions of other food sources such as copepod and nematode, POM, benthic microalgae to the total food uptake by sea cucumber averaged 22.6% - 39.1%, 6.3% - 22.2%, 2.8% - 6.5%, and 2.8% - 4.2%, respectively. Together these results indicated that the seasonal changes in food sources led to the obvious temporal differences in the relative contribution of various food sources utilized by A. japonicus. Such findings provide the basic scientific information for improving the aquaculture techniques of A. japonicus, particularly for optimizing the food environment of A. japonicus culture in farm ponds.

Identifying the sources of organic matter in marine and riverine sediments of Bohai Bay and its catchment using carbon and nitrogen stable isotopes

Carbon and nitrogen stable isotopes are useful tracers for distinguishing marine and terrestrial plant sources of sedimentary organic matter(OM),and for identifying OM from different types of plants.By analyzing the carbon and nitrogen stable isotopes of marine and riverine sediments from Bohai Bay and its catchment,we were able to identify the source of OM in these sediments.The stable carbon isotope values of Bohai Bay sediments were between-22.94‰ and-23.90‰,while those of riverine sediments were from-24.45‰ to-32.50‰.Marine algae were the main source of OM in Bohai Bay sediments.However,lacustrine algae were the main source of riverine sediments,not terrestrial OM.The nitrogen isotopes in Bohai Bay sediments decreased in eastward direction,with increasing distance from the coastline,which suggested a higher degree of impact from human activities along the coast.

Food sources of the Manila clam Ruditapes philippinarum in intertidal areas:evidence from stable isotope analysis

Based on stable isotope analysis, we characterized the dietary regime of the Manila clam Ruditapesphilippinarum inhabiting intertidal areas along the Liaodong Peninsula, Northern China. Samples, including particulate organic matter （POM; n=30）, benthic microalgae （BMI; n=30） and R. philippinarum （n=60）, were collected from six sampling sites displaying the same ecological conditions. Of the two primary food sources, POM was more depleted in δ13C （-20.61‰ to -22.89%0） than BMI was （-13.90‰ to -16.66‰）. With respect to 15N, BMI was more enriched （2.90%0 to 4.07%0） than POM was （4.13‰ to 5.12‰）. The δ13C values of R. philippinarum ranged from -18.78‰ to -19.35‰ and the δ15N values from 7.96%0 to 8.63‰, which were intermediate between the POM and BMI values. In a two-source isotope mixing model, we estimated the relative contributions of POM and BMI to the diet ofR. philippinarum to be 74.2% and 25.8%, respectively. We conclude that R. philippinarum feeds mainly on POM, and BMI is also an important supplemental food source in intertidal areas.

Synthesis, in-situ coating and characterization of scorodite with high leaching stability

To improve stability of scorodite,a method of simultaneous synthesis and in-situ coating of scorodite was proposed.Scorodite particles with polyhedral and raspberry-like morphologies were synthesized in an Fe(Ⅱ).As(Ⅴ).H2O system at 90℃and pH 1.5 by blowing oxygen gas into the system.When the initial Fe/As molar ratio exceeded 1:1,a coating of sulfate-containing iron(hydr)oxides formed on the surfaces of scorodite particles during synthesis.To evaluate the leaching stability of synthesized scorodite samples,toxicity characteristic leaching procedure(TCLP)tests were conducted at pH 4.93 for 60 h,and long-term leaching tests were conducted for 30.40 d within a pH range of 5.40.10.88.The leaching results indicated that the release of arsenic from scorodite was noticeably postponed by the coating,and the average arsenic concentrations in the leaching solutions were as low as 0.12 mg/L in the TCLP tests and lower than 0.5 mg/L in the long-term leaching tests.

Spacial hindrance induced recovery of over-poisoned active acid sites in pyridine-modified H-mordenite for dimethyl ether carbonylation

Zeolite catalysts,such as H-mordenite(H-MOR),are readily deactivated by coke deposition in carbonylation reactions.Pyridine modification of H-MOR can improve its stability but can lead to an undesirable loss in catalytic activity.Herein,we report the intrinsic impact of the pyridine adsorption behavior on H-MOR and the spacial hindrance of the zeolite frameworks on dimethyl ether(DME)carbonylation at a molecular level.We discovered that acid sites at O2 positions,located on common walls of eight-membered ring(8-MR)side pockets and 12-MR channels,were active in DME carbonylation,but were unfortunately poisoned during pyridine modification.Density functional theory calculations revealed that the pyridine-poisoned acid sites at the O2 positions could be easily regenerated due to the spacial hindrance of the zeolite frameworks.Accordingly,they can be facilely regenerated by proper thermal treatment,which induces 60%promotion in the catalytic activity along with a high stability.Our findings demonstrate the determining role of O2 positions in H-MOR for DME carbonylation and provide a new avenue for the rational design of other efficient zeolite-relevant catalytic systems.

Trophic Ecology of Sharks in the Mid-East Pacific Ocean Inferred from Stable Isotopes

As apex predators, sharks are of ecological and conservation importance in marine ecosystems. In this study, trophic positions of sharks were estimated using stable isotope ratios of carbon and nitrogen for five representative species caught by the Chinese longline fleet in the mid-east Pacific, i.e., the blue shark （Prionace glauca）, the bigeye thresher shark （Alopias superciliosus）, the silky shark （Carcharhinus falciformis）, the scalloped hammerhead （Sphyrna lewini）, and the oceanic whitetip shark （Car-charhinus longimanus）. Of these species, oceanic whitetip shark has the lowest trophic level and mean 815N value （3.9 and 14.93%o± 0.84%o）, whereas bigeye thresher shark has the highest level/values （4.5 and 17.02%o±1.21%o, respectively）. The bigeye thresher shark has significantly higher 515N value than other shark species, indicating its higher trophic position. The blue shark and oceanic whitetip shark has significantly higher 813C values than bigeye thresher shark, silky shark and scalloped hammerhead, possibly due to different diets and/or living habitats. The stable isotope data and stomach content data are highly consistent, suggesting that sta-ble isotope analysis supplements traditional feeding ecology study of sharks, and thus contributes to understanding their trophic linkage.

Trophic ecology of small yellow croaker (Larimichthys polyactis Bleeker): stable carbon and nitrogen isotope evidence

The trophic ecology of the small yellow croaker （Larimichthys polyactis） was studied using stable isotope analyses. Samples were collected from July to September 2009 and 34 individuals from eight sites were examined for stable carbon and nitrogen isotopes. Stable carbon isotope ratios （~3C） ranged from -20.67 to -15.43, while stable nitrogen isotope ratios （~SN） ranged 9.18-12.23. The relationship between fi^3C and ~SN suggested high resource partitioning in the sampling area. Significant differences in stable isotope values among the eight sampling sites may be linked to environmental diversities involving various physical processes （such as ocean current, wind and tide） and different carbon sources. Furthermore, the stable isotope ratios may also explain the ontogenetic variability in diet and feeding, because δ13C and δ15N varied significantly with increasing body size. The findings are consistent with other studies on diet analyses in small yellow croaker. It was also demonstrated that stable isotope analysis could be used to estimate the trophic characters of small yellow croaker in feeding patterns and migrating habits.

Application of Stable Isotope Tracing Technologies in Identification of Transformation among Waters in Sanjiang Plain,Northeast China

In order to investigate the transformation among the precipitation,groundwater,and surface water in the Sanjiang Plain,Northeast China,precipitation and groundwater samples which were collected at the meteorological station of the Sanjiang Mire Wetland Experimental Station,Chinese Academy of Sciences and the surface water which collected from the Wolulan River were used to identify the transformation of three types of water.The isotope composition of different kinds of water sources were analyzed via stable isotope(deuterium and oxygen-18) investigation of natural water.The results show a clear seasonal difference in the stable isotopes in precipitation.During the cold half-year,the mean stable isotope in precipitation in the Sanjiang Plain reaches its minimum with the minimum temperature.The δ18O and δD values are high in the rainy season.In the Wolulan River,the evaporation is the highest in August and September.The volume of evaporation and the replenishment to the river is mostly same.The groundwater is recharged more by the direct infiltration of precipitation than by the river flow.The results of this study indicate that the water bodies in the Sanjiang Plain have close hydrologic relationships,and that the transformation among each water system frequently occurs.