耕作方式对华北冬小麦田土壤微生物生物量碳分布特征的影响

土壤微生物生物量碳(SMBC)反映了土壤有机碳(SOC)情况,其值大小代表了土壤肥力的高低,研究不同耕作方式SMBC的变化特征及其影响因素具有重要意义。试验于2001年在中国科学院栾城农业生态系统实验站开始,试验设置翻耕(CT)、旋耕(RT)、免耕(NT)三个处理。利用熏蒸提取-容量分析法研究了不同耕作处理2007～2008年冬小麦生育期的SMBC分布特征及影响因素。结果表明SMBC具有时空变化特征:在冬小麦生育期中,各SMBC处理均随着时间波动起伏,并在小麦返青期和扬花期达到峰值;空间分布上SMBC含量随土壤深度的增加而降低。不同耕作处理间差异显著,0～5 cm土层SMBC以NT最高,CT最低;5～10 cm土层RT与CT相当,NT最低;10～20 cm土层以CT最高,NT最低;20～30 cm各处理均较低,NT亦为最低。对不同处理SMBC层化率分析显示:NT具有明显的表层富集现象;RT处理0～10 cm SMBC分布均匀;CT处理0～20 cm SMBC分布均匀。对SMBC的影响因素分析表明:土壤有机碳是SMBC空间分布的主要影响因素,二者呈显著正相关。而土壤温度和土壤含水量是影响SMBC季节变化的主要外界因素。

不同作物对连作玉米田土壤总有机碳与颗粒有机碳的影响

[目的]为了探究种植不同作物对连作玉米田土壤总有机碳及颗粒有机碳的影响。[方法]在连作玉米田分别种植红芸豆(CRK)、大豆(CSN)、高粱(CSM)三种作物,并以连作玉米(CCN)为对照,测定不同处理收获后土壤总有机碳含量、颗粒有机碳含量,计算土壤总有机碳和颗粒有机碳层化率以及土壤有机碳储量。[结果]除种植红芸豆在30～40 cm土层总有机碳含量增加外,其余处理的总有机碳含量随着土层深度的增加整体呈降低趋势。种植红芸豆在30～40 cm土层土壤总有机碳含量较种植玉米增加23.55%,种植高粱土壤总有机碳含量在0～5 cm土层分别比种植红芸豆、大豆和玉米降低10.26%、9.70%、7.52%。种植大豆能增加表层(0～5 cm)土壤有机碳储量和10～40 cm土层土壤颗粒组分比例,而对于提高土壤总有机碳含量和颗粒有机碳含量不显著。其次,种植红芸豆增加了0～40 cm土层土壤颗粒组分比例,其土壤颗粒有机碳含量显著高于种植玉米。[结论]在连作玉米田种植红芸豆较大豆、高粱显著提高5～10 cm和30～40 cm土层土壤有机碳含量以及耕层土壤颗粒组分比例和土壤颗粒态有机碳含量,对于土壤固碳和改善连作玉米田土壤质量有重要意义。

Experimental investigation of vibration pretreatment-microwave curing process for carbon fiber reinforced resin matrix composites

The vibration pretreatment-microwave curing process is an efficient,low energy consumption,and high-quality out-of-autoclave curing process for carbon fiber resin matrix composites.This study aims to investigate the impact of vibration pretreatment temperature on the fiber weight content,microscopic morphology and mechanical properties of the composite laminates by using optical digital microscopy,universal tensile testing machine and thermo-gravimetric analyzer.Additionally,the combined mode of Bragg fiber grating sensor and temperature measurement fiber was employed to explore the effect of vibration pretreatment on the strain process during microwave curing.The study results revealed that the change in vibration pretreatment temperature had a slight impact on the fiber weight content when the vibration acceleration remained constant.The metallographic and interlaminar strength of the specimen formed at a vibration pretreatment temperature of 80℃ demonstrated a porosity of 0.414% and a 10.69% decrease in interlaminar shear strength compared to autoclave curing.Moreover,the introduction of the vibration energy field during the microwave curing process led to a significant reduction in residual strain in both the 0°and 90°fiber directions,when the laminate was cooled to 60℃.

Optimizing data for electrical resistivity tomography in hardened sites through the ratio method

To reduce the shielding effect of hardened layers on electrical resistivity tomography,a ratio method based on the distortion correction principle and the isolation coefficient is proposed.The effects of the resistivity and thickness of hardened concrete layers on the detection of target objects are explored.Both numerical simulations and indoor tank tests indicate that when the ratio method is employed to correct the original collected data,the maximum allowable error for the isolation coefficient should not exceed 1%.Notably,when the ratio of hardened layer thickness to electrode spacing does not exceed 1,correction through this method significantly enhances the recognition capability of target objects.However,when the hardened layer thickness is greater than the electrode spacing by a factor of 2 or more,the ratio method cannot achieve satisfactory results.The case study of flood control engineering detection in the Zhangxi section of the Huangpen River in Dongzhi County demonstrates that the detection effect after correction by the ratio method is comparable to that for the adjacent unhardened pavement,and the influence of the hardened layer is obviously weakened,resulting in more reliable results.

水稻秸秆还田年限对稻麦轮作田土壤碳氮固存的影响

为明确连续秸秆还田对农田土壤碳氮固存的影响,该文于扬州大学试验场展开研究。田间试验布置于2010年,设置秸秆不还田(NR),秸秆还田1a(SR1),秸秆还田2a(SR2),秸秆还田3a(SR3),秸秆还田4a(SR4),秸秆还田5a(SR5),秸秆还田6a(SR6),秸秆还田7a(SR7),秸秆还田8a(SR8)9个处理。于2018年小麦收获后取样,测定分析了土壤容重、有机碳和全氮含量,计算碳氮比、层化率、土壤有机碳和全氮储量(等质量法)。结果表明,随着秸秆还田年限的增加,各土层有机碳和全氮含量逐渐提高,但增幅逐渐减小。0～5 cm土层土壤碳氮比在短期内(≤3 a)随着秸秆还田年限增加而显著提高,但是对其他土层和年限的无显著影响。随着秸秆还田年限增加,表层0～5 cm与其他层次有机碳和碳氮比层化率先增长后下降,全氮层化率则先下降后上升。秸秆还田处理0～20 cm土壤有机碳和全氮储量分别较NR提高6.23%～27.85%和6.04%～25.66%,各土层碳氮储量均随着秸秆还田年限的增加而提高,但是当还田年限>6a其增幅明显降低。综上所述,秸秆还田具有良好的碳氮固存效应,但是当秸秆还田年限>6a,土壤碳氮固存量的增幅明显降低,可适当减少还田量。

耕作方式对晋中玉米田土壤有机碳储量的影响

试验设置深翻秸秆不还田(PT)、深翻秸秆还田(PTS)、免耕秸秆不还田(NT)和免耕秸秆还田(NTS)4个处理,测定收获后耕层0~30 cm剖面土壤容重、有机碳含量及其储量,以探究不同耕作方式对晋中地区玉米田土壤有机碳储量的影响。结果表明,NTS和NT处理下土壤容重显著高于PT和PTS处理;NTS处理0~20 cm土层有机碳含量及其储量均最高,而PT处理20~30 cm土层有机碳含量及储量均显著高于其他处理;从0~30 cm剖面来看,NTS处理土壤有机碳储量显著高于其他处理。采用免耕秸秆还田措施可能是晋中地区玉米田潜在的土壤固碳途径。

Improvement in Performance of Carbon-based Perovskite Solar Cells through Interface Modification with CTAC

Carbon-based perovskite solar cells have attracted much attention,due to their low cost,simple preparation process and high chemical stability.However,the devices exhibit low photoelectric conversion efficiency,owing to the presence of defects and interface impedance between the perovskite active layer and the contact interface.In order to minimize the interfacial defects and improve the charge transfer performance between the perovskite layer and the contact interface,cetyltrimethylammonium chloride(CTAC)was introduced into the lower interface of HTL-free carbon-based perovskite solar cells,because CTAC can be used as interface modification material to passivate the buried interface of perovskite and promote grain growth.It was found that CTAC can not only passivate the interface defects of perovskite,but also improve the crystalline quality of perovskite.As a result,the photovoltaic conversion efficiency of reaches 17.18%,which is 12.5%higher than that of the control group.After 20 days in air with 60%RH humidity,the cell can still maintain more than 90%of the initial efficiency,which provides a new strategy for interfacial passivation of perovskite solar cells.

Growth and corrosion behaviors of thin anodic alumina membrane on AA5083 Al-Mg alloy in incalescent medium

A self-ordered porous film was fabricated on aluminum alloy in a ternary boric-sulfuric-oxalic acid electrolyte system. By means of voltage–time response, the oxidation process as well as the growth efficiency was studied. Field emission scanning electron microscopy（FE-SEM） was adopted to reveal the morphological and microstructural features of as-fabricated oxide layers. The corrosion protection properties of the films were investigated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The results showed that increasing the concentration of the double ionic layer located at the oxide interface could accelerate the film growth rate. The anodic oxidative layer with thickness of 8-9 μm and pore diameter of 10-14 nm maintains the pattern and topography of workpieces, compared with the overall closed film with hierarchical structure. Both samples exhibited much lower corrosion current density after boil water sealing. Meanwhile, a superior stability could be achieved through raising the ambient temperature.

Antisepsis and Fresh-keeping Effects of Natamycin Coating Compounds Treatment on Red Global Grape

The aim was to research fresh-keeping effects of natamycin on cold-pre- served grape. Red globe grapes were processed with compound coating liquid of chitosan with mass fraction at 1% and natamycin with mass fractions at 0.20% （T1）, 0.40% （T2） and 0.60% （T3）, respectively. Grapes processed with water （CK3） and 1% chitosan （CK2） were taken as control groups. Rotten rate, seed shattering rate, mass loss rate, respiratory intensity and related physiological quality in test and control groups were compared. The results indicated that respiratory intensity, mass loss rate, rotten rate and seed shattering rate in CK1 were all higher than those in CK2. In addition, T1, T2 and T3 were lower in the indices than CK1 and CK2, but still kept at a high level in fruit hardness. Furthermore, mass fractions of Vc and titratable acid declined more slowly in T1, T2 and T3, compared with CK1 and CK2. Natamycin better preserved grapes and prolonged storage period. In general, natamycin with mass fraction at 0.4% proved best in fresh-keeping.

Improvement on Frequency Performance of SOI SiGe HBT

Based on the advantages of SOI technology, the frequency performance of SiGe HBT with SOI structure has been simulated. Compared with bulk SiGe HBT, the results show that the buried oxide layer （BOX） can reduce collector-base capacitance CCB with the maximum value 89.3%, substrate-base capacitance CSB with 94. 6%, and the maximum oscillation frequency is improved by 2.7. The SOl structure improves the frequency performance of SiGe HBT, which is adaptable to high-speed and high power applications.

Schemes for Probabilistic Teleportation of an Unknown Three-Particle Three-Level Entangled state

In this paper, two schemes for teleporting an unknown three-particle three-level entangled state are proposed. In the first scheme, two partial three-particle three-level entangled states are used as the quantum channels, while in the second scheme, three two-particle three-level non-maximally entangled states are employed as quantum channels. It is shown that the teleportation can be successfully realized with certain probability, for both two schemes, ira receiver adopts some appropriate unitary transformations. It is shown also that the successful probabilities of these two schemes are different.

Wear behavior and dry sliding tribological properties of ultra-fine grained Al5083 alloy and boron carbide-reinforced Al5083-based composite at room and elevated temperatures

Tribological behavior and wear mechanisms of mechanically milled Al5083 alloy and Al5083−5wt.%B4C composite at room temperature and 200°C were discussed.Results revealed that due to the oxidative wear at room temperature,a mechanically mixed layer(MML)was formed to protect the surface of the samples.Under 80 N of load at room temperature,the milled Al5083 and the Al5083−5wt.%B4C samples showed evidence of abrasion with limited volume loss.In this case,the wear rates were 5.8×10−7 and 4.4×10−7 mm3/(m·N),respectively.At 200°C and under 80 N of applied load,severe wear occurred in the milled Al5083 sample,and wear rate reached 10.8×10−7 mm3/(m·N)while the Al5083−5wt.%B4C sample showed mild wear with local 3-body abrasion and the wear rate reached 5.3×10−7 mm3/(m·N).Strengthening mechanisms such as dislocation pinning and the Hall−Petch theory,high hardness and the load transfer effect were crucial in determining the wear behavior of the Al5083−5wt.%B4C composite.On the other hand,the milled Al5083 sample represented a relatively high wear rate at 200°C,which seemed to be related to the local grain growth and a drop in its hardness.

Chemical dissolution resistance of anodic oxide layers formed on aluminum

Chemically resistant anodic oxide layers were formed on pure aluminum substrates in oxalic acid-sulphuric acid bath.Acid dissolution tests of the obtained anodic layers were achieved in accordance with the ASTM B 680-80 specifications：35mL/L 85% H3PO4＋20g/L CrO3 at 38℃.Influence of oxalic acid concentration,bath temperature and anodic current density on dissolution rate and coating ratio was examined,when the sulphuric acid concentration was maintained at 160g/L.It was found that chemically resistant and compact oxide layers were produced under low operational temperature （5℃） and high current densities （3A/dm^2）.A beneficial effect was observed concerning the addition of oxalic acid （18g/L）.The morphology and the composition of the anodic oxide layer were examined by scanning electron microscopy （SEM）,atomic force microscopy （AFM） and glow-discharge optical emission spectroscopy （GDOES）.

Annealing time dependent structural, morphological, optical and electrical properties of RF sputtered p-type transparent conducting SnO_2/Al/SnO_2 thin films

Transparent p-type conducting SnO2/Al/SnO2 multilayer films were fabricated on quartz substrates by radio frequency(RF) sputtering using SnO2 and Al targets. The deposited films were annealed at a fix temperature of 500 °C for different time durations(1-8 h). The effect of annealing time on the structural, morphological, optical and electrical performances of SnO2/Al/SnO2 multilayer films was studied. X-ray diffraction(XRD) results show that all the p-type conducting films possess polycrystalline SnO2 with tetragonal rutile structure. Hall-effect results indicate that 500 °C for 1 h is the optimum annealing condition for p-type SnO2/Al/SnO2 multilayer films, resulting in a hole concentration of 1.14×1018 cm-3 and a low resistivity of 1.38 ?·cm, respectively. The optical transmittance of the p-type SnO2/Al/SnO2 multilayer films is above 80% within annealing time range of 1-8 h, showing maximum for the films annealed for 1 h.

Prediction on adsorption ratio of carbon dioxide to methane on coals with multiple linear regression

The multiple linear regression equations for adsorption ratio of CO2/CH4 and its coal quality indexes were built with SPSS software on basis of existing coal quality data and its adsorption amount of CO2 and OH4. The regression equations built were tested with data collected from some s, and the influences of coal quality indexes on adsorption ratio of CO2/CH4 were studied with investigation of regression equations. The study results show that the regression equation for adsorption ratio of CO2/CH4 and volatile matter, ash and moisture in coal can be obtained with multiple linear regression analysis, that the influence of same coal quality index with the degree of metamorphosis or influence of coal quality indexes for same coal rank on adsorption ratio is not consistent.

Transport Layer Optimization for Cloud Computing Applications via Satellite： TCP Noordwijk＋

Cloud computing can significantly improve efficiency in Internet utilization and data management.Several cloud applications(file sharing,backup,data up/download etc.) imply transfers of large amount of data without real-time requirements.In several use-cases cloud-computing solutions reduce operational costs and guarantee target QoS.These solutions become critical when satellite systems are utilized,since resources are limited,network latency is huge and bandwidth costs are high.Using satellite capacity for cloud-computing bulk traffic,keeping acceptable performance of interactive applications,is very important and can limit the connectivity costs.This goal can be achieved installing in the Set Top Box(STB) a proxy agent,to differentiate traffic and assign bandwidth according to priority,leaving spare capacity to bulk cloud computing traffic.This aim is typically reached using a specific QoS architecture,adding functional blocks at network or lower layers.We propose to manage such a process at transport layer only.The endpoint proxy implements a new transport protocol called TCP Noordwijk+,introducing a flow control differentiation capability.The proxy includes TPCN+ which efficiently transfers low-priority bulk data and handles interactive data,keeping a high degree of friendliness.The outcomes of Ns-2simulations confirm applicability and good performance of the proposed solution.

Effect of Different Dietary Protein and Lipid Levels on the Growth,Body Composition,and Intestinal Digestive Enzyme Activities of Juvenile Yellow Drum Nibea albiflora(Richardson)

An 8-week feeding trial was conducted to determine the optimal dietary protein-to-lipid ratio for juvenile Nibea albiflora with an initial weight of(11.76 ± 0.20) g.Nine experimental diets containing different concentrations of protein(40%,47%,or 54%) and lipids(5%,9%,or 13%) in a 3 × 3 factorial experimental design were tested in triplicate groups of fish,while the protein-to-energy(P/E) ratios of the diets varied in the range of 19.74–28.32 mg k J^(-1).Results showed that fish fed diets containing 9% or 13% lipids with 54% protein exhibited significantly higher weight gains and specific growth rates than those fed other diets.The feed conversion rate of fish fed the diet with 40% protein and 5% lipids was significantly poorer than that of fish fed other diets.The protein efficiency rate of fish fed diets with 5% lipids was significantly lower than that of fish fed 9% or 13% lipid diets.Carcass lipid and energy contents were positively correlated with dietary lipid level regardless of protein level.Fish fed a 54% protein diet showed the highest trypsin activity.The intestinal lipase activity of fish fed the diet containing 13% lipids was significantly higher than that of fish fed 5% or 9% lipid diets.These results demonstrate the high protein dietary requirements of N.albiflora.A diet containing 54% protein and 9%–13% lipids with a P/E ratio of 26.2–27.81 mg protein k J^(-1) can be considered optimal for juvenile N.albiflora.

Layered farming for Marsupenaeus japonicus Bate

Marsupenaeusjaponicus Bate is one of the most valuable cultured shrimp species in China and outdoor earthen pond farming is the most common method of culturing this organism. The need to increase soil usage efficiency in aquaculture has been recognized and a great deal of research effort has been directed toward development of super-intensive farming systems. However, current research and development in this field is largely devoted to Litopenaeus vannamei Boone, while to M.japonicus Bate it has been neglected. In this study, a layered fanning system was designed and a 66-day study was conducted in M.japonicus Bate culture. The system comprised bracket and sand layers that divided a shrimp tank filled to a depth of 1.2 m into four water layers. Conventional tank culture （unlayered） was used as a control. The results show that survival rate, feed conversion efficiency and production of M.japonicus Bate in the layered farming system were 68%, 18%, and 0.59 kg/m^2, respectively, all of which are significantly higher than in the unlayered fanning system （P〈0.01）. These findings confirmed the possibility of using a layered system to culture M. japonicus Bate.

Permeability variation characteristics of coal after injecting carbon dioxide into a coal seam

A theoretical basis for the optimization of carbon dioxide injection parameters and the development of the drainage system can be provided by identifying the permeability change characteristic of coal and rock after injection of carbon dioxide into the coal seam. Sihe, Yuwu, and Changcun mines were used as research sites. Scanning electron microscopy and permeability instruments were used to measure coal properties such as permeability and surface structure of the coal samples at different pH values of carbon dioxide solution and over different timescales. The results show that the reaction between minerals in coal and carbonate solution exhibit positive and negative aspects of permeability-the dissolution reaction between carbonate minerals in coal and acid solution improves the conductivity of coal whilst, on the other hand, the clay minerals in the coal （mainly including montmorillonite, illite and kaolinite） exhibit expansion as a result of ion exchange with the H~ in acid solution, which has a negative effect on the per- meability of the coal. The permeability of coal samples increased at first and then decreased with immer- sion time, and when the soaking time is 2-3 months the permeability of the coal reached a maximum. In general, for coals with permeabilities less than 0.2 mD or greater than 2 roD, the effect on the permeabil- ity is low： when the permeability of the coal is in the range 0.2-2 mD, the effect on the permeability is highest. Research into permeability change characteristics can provide a theoretical basis for carbon diox- ide injection under different reservoir permeability conditions and subsequent drainage.

GO-induced effective interconnection layer for all solution-processed tandem quantum dot light-emitting diodes

Compared to conventional quantum dot light-emitting diodes,tandem quantum dot light-emitting diodes(TQLEDs)possess higher device efficiency and more applications in the field of flat panel display and solid-state lighting in the future.The TQLED is a multilayer structure device which connects two or more light-emitting units by using an interconnection layer(ICL),which plays an extremely important role in the TQLED.Therefore,realizing an effective ICL is the key to obtain high-efficiency TQLEDs.In this work,the p-type materials polys(3,4-ethylenedioxythiophene),poly(styrenesulfonate)(PEDOT:PSS)and the n-type material zinc magnesium oxide(ZnMgO),were used,and an effective hybrid ICL,the PEDOT:PSS-GO/ZnMgO,was obtained by doping graphene oxide(GO)into PEDOT:PSS.The effect of GO additive on the ICL was systematically investigated.It exhibits that the GO additive brought the fine charge carrier generation and injection capacity simultaneously.Thus,the all solutionprocessed red TQLEDs were prepared and characterized for the first time.The maximum luminance of 40877 cd/m^(2) and the highest current efficiency of 19.6 cd/A were achieved,respectively,showing a 21%growth and a 51%increase when compared with those of the reference device without GO.The encouraging results suggest that our investigation paves the way for efficient all solution-processed TQLEDs.