提高亚临界锅炉差压式汽包水位测量准确度的改进措施

本文通过分析电站锅炉汽包差压式水位测量装置准确度不高的原因,提出了探讨性改进措施,并针对国华定洲电厂汽包水位测量不准的问题,提出了一些解决方案。

An Analytical Solution for One-Dimensional Water Infiltration and Redistribution in Unsaturated Soil

Soil infiltration and redistribution are important processes in field water cycle, and it is necessary to develop a simple model to describe the processes. In this study, an algebraic solution for one-dimensional water infiltration and redistribution without evaporation in unsaturated soil was developed based on Richards equation. The algebraic solution had three parameters, namely, the saturated water conductivity, the comprehensive shape coefficient of the soil water content distribution, and the soil suction allocation coefficient. To analyze the physical features of these parameters, a relationship between the Green-Ampt model and the algebraic solution was established. The three parameters were estimated based on experimental observations, whereas the soil water content and the water infiltration duration were calculated using the algebraic solution. The calculated soil water content and infiltration duration were compared with the experimental observations, and the results indicated that the algebraic solution accurately described the unsaturated soil water flow processes.

Stability Analysing of Unsaturated Soil Slope

The stability of unsaturated soil slope has been the hot point recently. Especially, the seeping rainfall makes losing stability of unsaturated soil slope, and causes enormous loss to the producation and safety of other people. The seeping rainfall makes volumetric water content of unsaturated soil slope changing, and the volumetric water content has directly relationship with matric suction. And matric suction also has directly relationship with the stability of unsaturated soil slope. So the change of matric suction influence the stability changing, that is, safety coefficient has decided relationship with volumetric water content. The profile of dangerous volumetric water content curves of unsaturated soil slope has been obtained. If a volumetric water content curve of some unsaturated soil slope belongs to one of these dongerous curves, the unsaturated soil slope could be in danger. So this is called DVWCCP(dangerous volumetric water content curves profile). By monitoring the volumetric water content curves can obtain the stability information of some soil slope to serve producing and safety.

Submesoscale characteristics and transcription of a fatty acid elongase gene from a freshwater green microalgae, Myrmecia incisa Reisigl

Myrmecia incisa is a green coccoid freshwater microalgae, which is rich in arachidonic acid （ArA, C20： 4ω-6, △5, 8, 11, 14）, a long chain polyunsaturated fatty acid （PUFA）, especially under nitrogen starvation stress. A cDNA library of M. incisa was constructed with λ. phage vectors and a 545 nt expressed sequence tag （EST） was screened from this library as a putative elongase gene due to its 56% and 49% identity to Marchantia polymorpha L. and Ostreococcus tauri Courties et Chretiennot-Dinet, respectively. Based upon this EST sequence, an elongase gene designated MiFAE was isolated from M. incisa via 5＇/3＇ rapid amplification of cDNA ends （RACE）. The cDNA sequence was 1 331 bp long and included a 33 bp 5＇-untranslated region （UTR） and a 431 bp 3＇-UTR with a typical poly-A tail. The 867 bp ORF encoded a predicted protein of 288 amino acids. This protein was characterized by a conserved histidine-rich box and a MYxYY motif that was present in other members of the elongase family. The genomic DNA sequence of MiFAE was found to be interrupted by three introns with splicing sites of Introns I （81 bp）, II （81 bp）, and III （67 bp） that conformed to the GT-AG rule. Quantitative real-time PCR showed that the transcription level of MiFAE in this microalga under nitrogen starvation was higher than that under normal condition. Prior to the ArA content accumulation, the transcription of MiFAE was enhanced, suggesting that it was possibly responsible for the ArA accumulation in this microalga cultured under nitrogen starvation conditions.

An improved Mesri creep model for unsaturated weak intercalated soils

The weak intercalated soils in redbed soft rocks of Badong formation have obvious creep characters. In order to predict the unsaturated creep behaviors of weak intercalated soils, an unsaturated creep model was established based on the unsaturated creep tests of weak intercalated soils by using GDS triaxial apparatus. The results show that the creep behaviors of intercalated soils are apparent and significantly affected by matric suction. Based on this, an empirical Mesri creep model for intercalated soils under varying matric suctions was built. The fitting results show that the parameters Ed and m of this model are in good power relations with matric suction s and stress level Dr, respectively. An improved Mesri creep model was established involving stress-matric suction-strain-time, which is more precise than the Mesri creep model in predicting the unsaturated creep behaviors of weak intercalated soils.

Lipids and fatty acids in Calanus sinicus during over-summering in the southern Yellow Sea

Over-summering is a crucial period for Calanus sinicus in the southern Yellow Sea,where it is a key member of the zooplankton community.Lipids play an important role in copepod diapause,which is part of their over-summering strategy.We investigated how different fatty acids and lipid classes,including wax esters,changed during over-summering of C.sinicus during three cruises in June and August 2011 and November 2010,corresponding to the pre-,during and post-diapause periods,respectively.Large amounts of lipids were accumulated,mainly wax esters as previously found in C.finmarchicus during its diapause,and most of the storage lipids were used during over-summering.Wax ester polyunsaturated fatty acids(PUFAs) showed the most variation of the fatty acids(FAs),while the percentage composition of FAs in polar lipids was relatively stable.Selective use of wax ester PUFAs has already been shown to play important roles in the winter diapause of Calanus species in other regions,and our FA results show that this is the case for the Yellow Sea Cold Bottom Water(YSCBW) population that diapauses in summer.

Influence of moisture content on shearing strength of unsaturated undisturbed quaternary system middle pleistocene

The unsaturated undisturbed quaternary system middle pleistocene loess,a typical unsaturated soil,often occurs in the implementation of western development strategy.To obtain the shearing strength characteristics of this unsaturated undisturbed loess,based on the analysis of mineral composition,the triaxial shear test of undisturbed quaternary system middle pleistocene loess under different moisture contents is conducted with the specialized triaxial instrument for unsaturated soil.The test results show that the mainly mineral composition of undisturbed quaternary system middle pleistocene loess is quartz and albite.Under the same confining pressure,the matric suction increases with the decrease of moisture content.The smaller the moisture content,the larger the matric suction;the higher the moisture content,the lower the matric suction.Under the same moisture content,the matric suction increases with the confining pressure and reaches a maximum when the confining pressure is 100 kPa,and then decreases with the increase of confining pressure.This phenomenon is closely related to the grain contact tightness of soil mass under high confining pressure.According to the triaxial test of loess,the sample of loess experiences 4 stages from loading to failure:1) compaction stage;2) compression stage;3) microcrack developing stage;4) shear failure stage.The test sample is of brittle failure(weak softening)under low moisture content and confining pressure.With the decrease of matric suction and the increase of consolidated confining pressure,the stress-strain curve changes from softening type to ideal plastic type.In the shearing strength parameters of unsaturated undisturbed loess,the influence of moisture content on internal friction angle is small,but that on cohesive force is obvious.Therefore,the shearing strength of unsaturated undisturbed loess is higher than that of saturated undisturbed loess and varies with the moisture content.

Effect of n-3 HUFA levels in rotifers and Artemia on growth and survival of larval black sea bream (Sparus macrocephalus)

Requirement for dietary n-3 HUFA (n-3 highly unsaturated fatty acid) for growth and survival of black sea bream (Sparus macrocephalus) larvae was studied using rotifers and Artemia at various levels of n-3 HUFA. Five treatments with rotifers and Artemia differing in n-3 HUFA were prepared by enriching them with various oil emulsions. Results indicated that dietary n-3 HUFA significantly influence fish n-3 HUFA levels and are essential for growth and survival of black sea bream larvae. The results also indicated that the incorporation of n-3HUFA TG (triacylglycerols) into tissues of larval black sea bream was more effective from natural fish oil in comparison with n-3 HUFA fatty acid ethyl esters from ethyl-esterified oil.

Changing of Properties of Unsaturated Compacted Bentonite due to Hydration Effort

Radioactive waste disposal is important facility for human and environment in the world. Compacted bentonite in radioactive disposal engineer barrier design really experience hydration effort as decreasing of suction during long-time. Hydration effort develop macro-micro void structure in bentonite under deeply geological environment. The bentonite occurred uncertainly problems or translation in various experimental interaction boundary conditions such as thermal-hydration-chemical condition. To detect accumulation of deformation or changing of bentonite behaviour due to these processes is important that the modified experimental methods are required. In addition, to interpret laboratory experimental results combine to establish mathematical modelling in possible. The overall investigation or performance of the bentonite have contributed to represent the intrinsic properties of engineer barrier systems. This study focused on changing of properties of unsaturated compacted bentonite related to hydration effort due to increasing of relative humidity. Changing of some properties revealed to become instability or uncertainly problems in practice. Soil-water characteristic curve was measured with considering of various temperatures using vapor pressure technique. Swelling pressure and creep behaviour such as mechanical components were described with hydration effort.

Study of Water Movement in Unsaturated Copper Ore

Leaching is widely applied in the exploitation of depleted ores. In order to discover the law of leachant movement in the leaching process and calculating volumes and time intervals of spraying leachant,experiments and numerical simulation with the TOUGH2/EOS3 module were carried out in order to find out the principle of water movement in unsaturated copper ore. The results show that water volume increases at the same location over time,that copper ore tends to become saturated and that liquid velocity decreases at the same time as the distance from top in-creases. On the other hand,a comparison and analysis of our experimental and simulated results indicate that the EOS3 module could accurately simulate the water movement in an unsaturated state.

Effect of Dietary Lipid Levels on Fatty Acids Composition of Cultured Sparusaurata

The aim of this study was to determine the progressive evolution of fish muscle fatty acids composition feeding by different lipid levels of farmed Mediterranean gilthead sea bream （Sparusaurata）. During twenty one weeks, Sparusaurata were hand-feed two diets with protein and lipid ratios 47/20 （Diet A） and 45/22 （Diet B） respectively. At the end of the feeding period, lipid contents of muscle, as well as fatty acids profiles of different portions of the muscles were studied. Results indicated the effects of fatty acids profiles of diets throughout the liver and white muscle fillet （dorsal, middle and ventral）. These were more noticeable when Sparusaurata was fed on the diet Athat decreased the content of monounsaturated fatty acids （MUFA）, and polyunsaturated fatty acids （PUFA） in all the muscles during the period of feeding while the saturated fatty acids （SFA） content tended to increase and it was lower than ones in the muscles of Sparusaurata fed on diet B. The highest amount of PUFA and docosahexaenoic acid, （22：6n-3 DHA） were found among the different portions of ventral muscles. In addition, the progressive evolution of different parts of muscle＇s fatty acid profiles showed significant differences in contents of SFA, PUFA and especially the n-3 PUFA. However, the content of MUFA seems to be alike in different muscles and tended to decrease in dorsal and ventral muscle from Do to Df and inversely when the fish were fed on diet A.

Nutrient effects of broodstocks on the larvae in Patinopecten yessoensis

Patinopecten yessoensis is a commercial valuable species. This study deals with the effect of nutrient effects of the broodstock(mainly ovaries) on the larvae. Concentrations of total carbohydrate, total protein and total lipid in the gonads of P. yessoensis from three Hatcheries(Hatchery 1, Hatchery 2, and Hatchery 3) were determined before and after spawning. The relationship between the nutrient concentration in ovaries before spawning(BC) and that of larvae(LC) was assessed as well as the change in nutrient levels in ovaries after spawning(DC). Results indicate that the BC of total carbohydrate(7.66%) and total lipid(14.48%) in ovaries were significantly higher than in testes(5.20%, 5.20% respectively), whereas the BC of total protein in the ovaries was lower(61.76%) than in the testes(81.67%). The different gonadal composition suggests the different nutrient demands between male and female broodstocks in breeding season. P atinopecten yessoensis gonads contained a higher proportion of lipids, in comparison to other bivalves, which might be a response to the low ambient water temperatures. Further analysis of fatty acids showed that the concentrations of n-3PUFA, EPA and DHA in larvae(LC) were positively correlated with BC and DC, indicating the significant nutrient influence of broodstocks on the larvae. As these fatty acids are important in metabolism, and have been demonstrated to be influential to the viability of the larvae, larval growth and the settlement, spat growth, and juvenile survival in many bivalves, they could possibly be used as indexes to evaluate, and predict condition of broodstocks and larvae.

Effect of Ice Storage on Fatty Acids Profile of Freshwater and Marine Fishes Available at Malaysia Wet Market

This study was conducted in the intention to identify and determine the fatty acid profile in freshwater fishes and marine fishes available at Malaysian wet market as well as its deterioration kept in ice storage up to 21 days. Three freshwater fishes： Oreochromis sp. commonly known as Tilapia, Monopterus alba commonly known as Belut, Pangasius hypothalamus commonly known as Patin and marine fish Rastrellinger kanagurta commonly known as Kembung, Thunnus tonggol commonly known as Tongkol and Epinephelus sp. commonly known as Kerapu with average weight of 500-600 g were tested with storage time of 1, 3, 6, 9, 12, 15. 18 and 21 days kept ice storage. The Fatty Acid Methyl Ester （FAMEs） were prepared using one step method and were identified by using gas chromatograph Agilent 6890N equipped with flame ionization detector. Separation was performed by injecting 1μL of a sample into the capillary column DB-225MS column （30 m length × 0.250 mm diameter × 0.25 μm film thickness）. The fatty acids peaks were indentified using Agilent Technologies software 5988-5871EN and comparing their retention time against the authentic standard Supelco 37 Component FAME Mix. Statistical results showed that palmitic acid （CI6：0） were the major fatty acids among the saturated fatty acids （SFA） while oleic acid （C 18：1 n9） were the major monounsaturated fatty acids （MUFA） detected in each sample studied. Both linoliec acid （C 18：2n6） and arachadonic acid （C20：4n6） were predominant in total omega-6 polyunsaturated fatty acids （PUFA）. The essential fatty acids show prominent in ecosapentanoic acid （C20：5n3） and docosahexanoic acid （C22：6n3）. During ice storage polyunsaturated fatty acids （PUFA） and monounsaturated fatty acids （MUFA） decrease as the time of storage increase. There is significant decrease in polyene index （PI） index of all the species throughout the storage time, The PI in freshwater fishes decrease by 70% in Tilapia, 90.1% in Belut and 90.9% in Patin, while for marine fishes, PI in Kembung decreases by 67.8%, 85.7% in Kerapu and 65.93% in Tongkol during kept in ice storage. During ice storage, the percentage of EPA, DHA and ALA decrease in Tilapia （55.36%, 13.86% and 75.41%）, Belut （78.55%, 87.74 % and 74.53%） and Patin （82.45%, 40.0% and 82.10%）, respectively. The same result were also observed in the marine fishes where the percentage ofEPA, DHA and ALA decrease in Kembung （94.27%, 49.03% and 88.52%）, in Kerapu （73.03%, 88.18% and 38.73%） and Tongkol （70.05%, 38.24% and 57.14%）, respectively.

Regulating Neuronal Hyper-Excitability and Hyper-Synchrony in Epileptic Patients by Using PUFA, Calcium and ATP Buffering

Epilepsy is a severe neurological disorder clinically identified by hyper-excitability and/or hyper-synchrony in the cortex and other subcortical regions of the brain. To regulate such excitability and synchrony, Hodgkin and Huxley model has been deployed with either PUFA or calcium buffering coupled with ATP modulate neurotransmitter release. We formulate and analyze a system of differential equations that describe the effects of PUFA, ATP, and calcium buffering in regulating neuronal hyper-excitability and hyper-synchrony in epileptic patients. We observed that PUFA had diverse effects on the gating variables. Specifically, there was a significant reduction in the inhibitory potency of PUFA on the m-gates which may cause a direct inhibition of the voltage-gated Na＋ channels and thus reduce neuronal excitability in epileptic patients. Also, the activation of the potassium channels by PUFA directly limited the neuronal hyper-excitability, while a small change in voltage potential coupled with PUFA restraint activated the voltage dependent ion channels which aided in lowering epileptic excitability in patients. In addition, higher ATP buffer levels in the presence of PUFA caused a significant hyperpolarization which may decrease neuronal excitability while lower ATP level initiated neuron depolarization. These results clearly suggest that PUFA coupled with calcium and ATP buffering could be used to modulate neuronal excitability excessive synchrony in epileptic patients.

Assessment of Nutrients of Escamoles Ant Eggs Limotepum apiculatum M. by Spectroscopy Methods

Edible insects, escamoles ant eggs of the Formicidae family are consumed by cultural tradition at rural communities and by sensory characteristics at high class restaurants of Mexico; however, people ignore the importance of insect consumption in the nutrition of humans. Laboratory spectroscopy methods in food analysis represent benefits in time and precision. The aim of this study is to assess macronutrients and micronutrients of escamoles and eggs by spectroscopic methods to inform population the benefits they provide in health and to mention the advantage in the use of these techniques at laboratory work. Samples were gather the second week of March and April 2012, at Hidalgo State and analyze moisture and macronutrients by AOAC （Association of Official Analytical Chemistry） methods, amino acids by cation exchange chromatography, tryptophan was determined by a colorimeter method, fatty acids by GC （gas chromatography） using helium as a carrier （AOAC）, fat soluble vitamins A, D and E by HPLC （high performance liquid chromatography）, and minerals by atomic absorption spectrophotometers and phosphorus by colorimeter （AOAC）. Data showed high amount in proteins, lipids and minerals; low in fiber and soluble carbohydrates; contained all essential amino acids. Fatty acids contain monounsaturated and polyunsaturated. Fat soluble vitamins A, D and E. Minerals： sodium, phosphorus, potassium, magnesium, calcium and manganese. Escamoles ant eggs include polyunsaturated fatty acids essential for mental development, vitamin A to prevent eye diseases, vitamin E as antioxidant and vitamin D involved in calcium absorption that low intake, impair grow and bone health. Iron and zinc contained anemia. Regarding the laboratory benefits, needs less expensive chemicals, testing is clean, rapid and easy results of multiple samples, but it is required to handle by qualified chemists. In conclusion, data may change according to biotic and abiotic conditions of the environment; however, escamoles have all nutrients in adequate balance to improve human health; and provide faster and precise results.

Influence of dietary n-3 LC-PUFA on growth, nutritional composition and immune function in marine fish Sebastiscus marmoratus

Abstract A 60-day feeding experiment was conducted to investigate the influence of dietary omega-3 long-chain polyunsaturated fatty acids （n-3 LC-PUFA） on growth, nutritional composition and immune function of marine fish Sebastiscus marmoratus. Five diets containing 3.6, 10.2, 18.2, 26.5, or 37.0 g/kg n-3 LC-PUFA were prepared. The results reveal significant influences of dietary n-3 LC-PUFA on the final weight, weight gain, specific growth rate, feed conversion ratio, and condition factor. As dietary n-3 LC- PUFA increased, weight gain and specific growth rate increased and were significantly higher in groups fed 18.2, 26.5 and 37.0 g/kgthan in groups fed 3.6 and 10.2 g/kg （P〈0.05）; there was no significant difference between groups fed 18.2, 26.5, or 37.0 g/kg （P〉0.05）. With increasing dietary n-3 LC-PUFA, eicosapentaenoic acid and docosahexenoic acid content in muscle and liver increased significantly, immunoglobulin class M content gradually increased from 9.1 to 14.8 Ixg/L, and lysozyme activity content increased from 1 355 to 2 268 U/mL. Broken line model analysis according to weight gain indicated that a dietary n-3 LC-PUFA level of 18.2 g/kg is essential for normal growth at a fat level of 125 g/kg. Therefore, appropriate dietary n-3 LC-PUFA not only promote growth and improve the n-3 LC-PUFA content, but also enhance immune function in S. marmoratus.

Large unsaturated positive and negative magnetoresistance in Weyl semimetal TaP

After successfully growing single-crystal TaP, we measured its longitudinal resistivity （Pxx） and Hall resistivity （Pyx） at magnetic fields up to 9 T in the temperature range of 2-300 K. At 8 T, the magnetoresistance （MR） reached 3.28 ×10^5% at 2 K, 176% at 300 K. Neither value appeared saturated. We confirmed that TaP is a hole-electron compensated semimetal with a low carrier concentration and high hole mobility ofμh=3.71 × 105 cm2/V s, and found that a magnetic-field-induced metal-insulator transition occurs at room temperature. Remarkably, because a magnetic field （H） was applied in parallel to the electric field （E）, a negative MR due to a chiral anomaly was observed and reached -3000% at 9 T without any sign of saturation, either, which is in contrast to other Weyl semimetals （WSMs）. The analysis of the Shubnikov-de Haas （SdH） oscillations superimposed on the MR revealed that a nontrivial Berry＇s phase with a strong offset of 0.3958, which is the characteristic feature of charge carriers enclosing a Weyl node. These results indicate that TaP is a promising candidate not only for revealing fundamental physics of the WSM state but also for some novel applications.