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As a critical source of food and one of the most economically significant crops in the world, soybean plays an important role in achieving food security. Large area accurate mapping of soybean has long been a vital, but challenging issue in remote sensing, relying heavily on large-volume and representative training samples, whose collection is time-consuming and inefficient, especially for large areas (e.g., national scale). Thus, methods are needed that can map soybean automatically and accurately from single-date remotely sensed imagery. In this research, a novel Greenness and Water Content Composite Index (GWCCI) was proposed to map soybean from just a single Sentinel-2 multispectral image in an end-to-end manner without employing training samples. By capitalizing on the product of the NDVI (related to greenness) and the short-wave infrared (SWIR) band (related to canopy water content), the GWCCI provides the required information with which to discriminate between soybean and other land cover types. The effectiveness of the proposed GWCCI was investigated in seven typical soybean planting regions within four major soybean-producing countries across the world (i.e., China, the United States, Brazil and Argentina), with diverse climates, cropping systems and agricultural landscapes. In the experiments, an optimal threshold of 0.17 was estimated and adopted by the GWCCI in the first study site (S1) in 2021, and then generalised to the other study sites over multiple years for soybean mapping. The GWCCI method achieved a consistently higher accuracy in 2021 compared to two conventional comparative classifiers (support vector machine (SVM) and random forest (RF)), with an average overall accuracy (OA) of 88.30% and a Kappa coefficient (k) of 0.77; significantly greater than those of RF (OA: 80.92%, k: 0.62) and SVM (OA: 80.29%, k: 0.60). Furthermore, the OA of the extended years was highly consistent with that of 2021 for study sites S2 to S7, demonstrating the great generalisation capability and robustness of the proposed approach over multiple years. The proposed GWCCI method is straightforward, reliable and robust, and represents an important step forward for mapping soybean, one of the most significant crops grown globally.

In this paper, a novel hybrid-arm modular multilevel converters (HA-MMCs) topology with DC low voltage operation and fault ride-through capability is proposed for unidirectional HVDC bulk power transmission. The HA-MMCs topology is a combination of two types of converter arms: the half-bridge sub-module based arm (HBSM-arm) and the diagonal bridge sub-module based arm (DBSM-arm). Replacing the traditional HBSM-MMC, the HA-MMCs are operated in current and reactive power control modes during normal conditions and can work as the rectifier or the inverter. Since the DBSM can provide bipolar voltages with unipolar currents, the HA-MMCs need not change its control strategy under DC low voltage conditions caused by the high-impedance faults. Under DC pole-to-pole or pole-to-ground faults, the HA-MMCs can both clear the DC fault current and work as the static synchronous compensator (STATCOM) to provide reactive power to support the AC grid. Compared with other MMC topologies with DC fault ride-through capability, the HA-MMCs topology is more economical for significantly decreasing the number of power devices. The operation states, control strategy and DC low voltage operation capability of the HA-MMCs are presented and simulation results of the LCC-HA-MMC hybrid system using PSCAD/EMTDC validate the characteristics and advantages of the HA-MMCs.

Swarm intelligence algorithms have been widely used in the dimensional reduction of hyperspectral remote sensing imagery. The ant colony algorithm (ACA), the clone selection algorithm (CSA), particle swarm optimization (PSO), and the genetic algorithm (GA) are the most representative swarm intelligence algorithms and have often been used as subset generation procedures in the selection of optimal band subsets. However, studies on their comparative performance for band selection have been rare. For this paper, we employed ACA, CSA, PSO, GA, and a typical greedy algorithm (namely, sequential floating forward selection (SFFS)) as subset generation procedures and used the average Jeffreys–Matusita distance (JM) as the objective function. In this way, the band selection algorithm based on ACA (BS-ACA), band selection algorithm based on CSA (BS-CSA), band selection algorithm based on PSO (BS-PSO), band selection algorithm based on GA (BS-GA), and band selection algorithm based on SFFS (BS-SFFS) were tested and evaluated using two public datasets (the Indian Pines and Pavia University datasets). To evaluate the algorithms’ performance, the overall classification accuracy of maximum likelihood classifier and the average runtimes were calculated for band subsets of different sizes and were compared. The results show that the band subset selected by BS-PSO provides higher overall classification accuracy than the others and that its runtime is approximately equal to BS-GA’s, higher than those of BS-ACA, BS-CSA, and BS-SFFS. However, the premature characteristic of BS-ACA makes it unacceptable, and its average JM is lower than those of other algorithms. Furthermore, BS-PSO converged in 500 generations, whereas the other three swarm-intelligence based algorithms either ran into local optima or took more than 500 generations to converge. BS-PSO was thus proved to be an excellent band selection method for a hyperspectral image.

[Introduction] Energy storage is an important component and key supporting technology of Energy Internet. It can provide various services such as peak shaving and frequency modulation. It is an important means to enhance the flexibility, economy and safety of traditional power system. [Method] This paper reviewed the characteristics of the existing main energy storage technologies, and analyzed the functions and requirements of energy storage at power supply side, user side and grid side. According to the status quo of application, the key issues of safety, economy and business model of energy storage are pointed out. [Result] The results show that the energy storage operation simulation, multiple combination utilization, combination of concentration and dispersion should be strengthened from the perspective of energy storage application. [Conclusion] This work provides some guidance for further study on the application research and development of energy storage technology.

Regional integrated energy system(RIES) is the specific realization link of integrated energy system(IES), and is an important part of solving the problems of new energy absorption and environmental pollution aggravation. With the development of energy utilization and social environment, carbon emissions trading has linked environmental benefit and economic benefit. Therefore, how to achieve the economic and environmental benefits of the system while operating safely and steadily should be focused for RIES. However, the existing optimization schemes are not considered enough in feasibility or system stability check. For this purpose, this paper establishes a linear model of RIES operation optimization. In this paper, the penalty function of pollution be introduced, and the environmental factor and economic indicators be effectively unified. This paper proposes the comprehensive cost indicators, and analyses the comprehensive cost minimization under the steady-state constraints of power flow. A RIES case system is analyzed in this paper. The calculation and analysis based on the RIES case shows that the comprehensive operation cost index and optimization model can be effectively used for system operation optimization, taking into account the economy and environmental protection of system operation, ensuring the lowest comprehensive operation cost, and verifying the effectiveness of the optimization results through the RIES comprehensive energy efficiency and RIES stability verification and assessment indicators.

A copper-catalyzed one-pot amine-alkylation of quinones with amines and alkanes in the presence of di-tert-butyl peroxide (DTBP) was developed via a radical reaction process. Various alkanes and aromatic or aliphatic amines with diverse structures and electronic properties are suitable substrates, and the chirality of amines can be maintained for the transformation. This method has high step and atom economy for straightforward access to aminated and alkylated quinones from readily available starting materials.

Color image steganography based on deep learning is the art of hiding information in the color image. Among them, image hiding steganography(hiding image with image) has attracted much attention in recent years because of its great steganographic capacity. However, images generated by image hiding steganography may show some obvious color distortion or artificial texture traces. We propose a color image steganographic model based on frequency sub-band selection to solve the above problems. Firstly, we discuss the relationship between the characteristics of different color spaces/frequency sub-bands and the generated image quality. Then, we select the B channel of the RGB image as the embedding channel and the high-frequency sub-band as the embedding domain. DWT(discrete wavelet transformation) transforms B channel information and secret gray image into frequency domain information, and then the secret image is embedded and extracted in the frequency domain. Comprehensive experiments demonstrate that images generated by our model have better image quality, and the imperceptibility is significantly increased., Comment: 19 pages,17 figures

Monolayer transition metal dichalcogenides (TMDCs) are two-dimensional (2D) materials with many potential applications. Chemical vapour deposition (CVD) is a promising method to synthesize these materials. However, CVD-grown materials generally have poorer quality than mechanically exfoliated ones and contain more defects due to the difficulties in controlling precursors' distribution and concentration during growth where solid precursors are used. Here, we propose to use thiol as a liquid precursor for CVD growth of high quality and uniform 2D MoS2. Atomic-resolved structure characterizations indicate that the concentration of sulfur vacancies in the MoS2 grown from thiol is the lowest among all reported CVD samples. Low temperature spectroscopic characterization further reveals the ultrahigh optical quality of the grown MoS2. Density functional theory simulations indicate that thiol molecules could interact with sulfur vacancies in MoS2 and repair these defects during the growth of MoS2, resulting in high quality MoS2. This work provides a facile and controllable method for the growth of high-quality 2D materials with ultralow sulfur vacancies and high optical quality, which will benefit their optoelectronic applications., 23 pages, 6 figures, Small, 2020, Accepted

A novel DC traction power supply system suitable for energy feeding and de-icing is proposed in this paper for the urban rail transit catenary on the basis of the full bridge submodule (FBSM) modular multilevel converter (MMC). The FBSM-MMC is a novel kind of voltage source converter (VSC) and can directly control the output DC voltage and conduct bipolar currents, thus flexibly controlling the power flow of the urban rail transit catenary. The proposed topology can overcome the inherent disadvantages of the output voltage drop in the diode rectifier units, increase the power supply distance and reduce the number of traction substations. The flexible DC technology can coordinate multiple FBSM-MMCs in a wide area and jointly complete the bidirectional control of catenary power flow during the operation of the electric locomotive, so as to realize the local consumption and optimal utilization of the recovered braking energy of the trains. Besides, the FBSM-MMCs can also adjust the output current when the locomotive is out of service to prevent the catenary from icing in winter. The working modes of the proposed topology are illustrated in detail and the control strategy are specially designed for normal locomotive operation and catenary de-icing. Simulation cases conducted by PSCAD/EMTDC validate the proposed topology and its control strategy.

China, the largest coal producer in the world, is responsible for over 50% of the total global methane (CH4) emissions from coal mining. However, the current emission inventory of CH4 from coal mining has large uncertainties because of the lack of localized emission factors (EFs). In this study, province-level CH4 EFs from coal mining in China were developed based on the data analysis of coal production and corresponding discharged CH4 emissions from 787 coal mines distributed in 25 provinces with different geological and operation conditions. Results show that the spatial distribution of CH4 EFs is highly variable with values as high as 36 m3/t and as low as 0.74 m3/t. Based on newly developed CH4 EFs and activity data, an inventory of the province-level CH4 emissions was built for 2005–2010. Results reveal that the total CH4 emissions in China increased from 11.5 Tg in 2005 to 16.0 Tg in 2010. By constructing a gray forecasting model for CH4 EFs and a regression model for activity, the province-level CH...

Conventional brain-computer interface (BCI) systems have been facing two fundamental challenges: the lack of high detection performance and the control command problem. To this end, the researchers have proposed a hybrid brain-computer interface (hBCI) to address these challenges. This paper mainly discusses the research progress of hBCI and reviews three types of hBCI, namely, hBCI based on multiple brain models, multisensory hBCI, and hBCI based on multimodal signals. By analyzing the general principles, paradigm designs, experimental results, advantages, and applications of the latest hBCI system, we found that using hBCI technology can improve the detection performance of BCI and achieve multidegree/multifunctional control, which is significantly superior to single-mode BCIs.

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the determination and pharmacokinetic investigation of parthenolide in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2mL of acetonitrile containing 30ng/mL of pirfenidone (IS), and to a 0.1mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 3.0min and the elution of parthenolide was at 1.33min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring (MRM) mode using the respective transitions m/z 249.2→231.1 for parthenolide and m/z 186.2→92.1 for pirfenidone (IS), respectively. The calibration curve was linear over the range of 2.0-500ng/mL with a lower limit of quantitation (LLOQ) of 2.0ng/mL. Mean recovery of parthenolide in plasma was in the range of 78.2-86.6%. Intra-day and inter-day precision were both

Sentiment analysis of reviews has been the focus of recent research, which also has been attempted in different domains such as product reviews, movie reviews, and customer feedback reviews. Most sentiment analysis of reviews focused on extracting overall evaluation for a single product which makes difficult for a customer to know all the features of product and make a decision. Thus, mining this data, identifying the user opinions about different features and classify them is an important task. This paper is devoted to identify opinion object from short comments, and analyze sentiment of product based on features-level. CRFs model based on word embedding feature is adopted by identifying opinion object, which obtains a satisfied results. In addition, calculate rules based on syntax parsing are proposed to accomplish features-level sentiment analysis which extracts user's opinion on many aspects. Experimental results using short comments of movies show the effectiveness of our approach.

The biogas production characteristics of anaerobic fermentation of cattle manure and corn stover with different proportions were studied to provide basis for improving efficiency. The dry matter mass ratio of corn stover and cattle manure was set as 1:1,1:2,1:3 and 2:1 respectively. The anaerobic co-digestion was carried out under the fermentation conditions of 8% TS and medium temperature (35±1°C), analysing the change rule of each biomethane production index. The results showed that when the mass ratio of corn stover to cattle manure was 2:1, daily biogas production was up to 80 mL; compared with 1:2 and 1:3, the maximum cumulative biomethane production volume of 4540mL increased by 21.67% and 30.12% respectively. The highest volume fraction of methane is 72%.

The couplings between different types of energy networks are receiving increasing attention, especially in distribution networks. One of the fundamental topics of interest is the dynamic coupling between power grids and gas networks. To study dynamics in gas pipelines and the interaction between gas networks and electric power grids, dynamic modeling of gas networks gives the foundation. Commercial software is available and mature, but has flaws: (1) time-consuming simulation and complex implementation, and (2) the interface to electric power grids is not friendly. In this paper, transfer functions (TFs) are used to model a single pipeline. To model a gas network with multiple pipelines, a universal networking method is proposed. The accuracy of transfer function models are thoroughly examined under step and sinusoidal excitations, and the influence factors of accuracy is investigated. The adaptability of TF models is then quantitated by reference curves. Finally, the proposed modeling approach is applied in analyzing a gas-electricity system to test its capabilities.

In order to explore the optimal ratio of pig manure and wheat straw mixed fermentation process, the experiment controlled the temperature of the fermentation control fermentation process to 35 °C, the total mass of the fermentation liquid was 700 g, and the total soild (TS) was 8%. The effect of pig manure content on fermentation. Based on the analysis of the gas production per unit of TS, when the pig manure content is 80%, the unit TS produced has the highest gas yield of 344 ml/g, which is 58.9% higher than that of pure wheat straw fermentation. Fermentation increased by 11.43%. In order to explore the best pig manure content in the fermentation process, regression analysis was performed on the gas production per unit of TS by origin. The result was that when the content of pig manure was 79%, the gas production was the highest, 336.3 ml/g, which was higher than that of wheat straw fermentation. 55.51%, 9.05% higher than pure pig manure fermentation. The methane content was used as the analysis result: when the pig manure content was 75%, the highest average methane content after start-up was 60.33%, which was 15.24% higher than that of wheat straw alone, and 3.4% higher than that of pig manure alone. Therefore, during the fermentation process of pig manure and wheat straw, when the content of pig manure is controlled at about 75%, the biogas production in the fermentation process and the methane content in the biogas can be effectively improved..

Flight path planning by artificial immune algorithm approach met the requirements of aircraft's flyability and operation is proposed for the problem of single and double TF/TA2 flight path planning. Punishment function (affinity function) with comprehensive 3D threat information is designed. A comprehensive threat model is formed including dynamic and static threats and no-fly-zone. Accordingly, single and dual flight paths are planned by AIA, which have been compared with the paths by GA. The results show that, GA's planned a quick and longer path compared under simple threat environment; in complex environments, GA has high failure rate (greater than 95%) for single aircraft, but it is failed for double aircrafts. For the single and double aircrafts, AIA can provides one optimal and more candidate optimal flight paths.

Currently, most sentiment analysis of microblog has been focused on coarse-grained sentiment analysis, but fine-grained sentiment is better for reflecting the opinion of the public when they are facing the social focus. Therefore, a hybrid strategy which is a combination of Naive Bayesian and two-layer CRFs is put forward, which has been applied to the finegrained sentiment analysis of Chinese microblog. First, microblog is classified into two types: sentiment and non-sentiment by using Naive Bayesian classification algorithm. And then the first-layer CRFs model is built for the topic emotional sentence. Finally CRFs algorithm is used again to do multi-classification to assign a specific sentiment category. Experimental results show that a good result in sentiment identification based on the combination of Naive Bayesian and CRFs, and also show the advantage of the combination of Naive Bayesian and CRFs interrelated with emotional sentence extraction based on CRFs.

To measure unbalanced moments, the knife-edge is used as a support module in traditional platforms, but performances rapidly deteriorate as the edge is worn down. In this paper, considering the requirements of measurements, a two degree-of-freedom (DOF) flexure mechanism is, thus, presented to overcome this drawback. First, off-axis stiffness and manufacturability are improved qualitatively by means of configuration analysis. Then, four generalized cross-spring pivots are exploited in the 2DOF flexure mechanism, and the geometric parameters are analyzed to achieve approximately constant rotational stiffness and reduced center shift simultaneously, which benefits calibration procedure and measurement precision. Models are further developed to determine the shape parameters of leaf-springs and transducer performances. Therefore, a low rotational stiffness is obtained to ensure a high resolution for measurements, and a high load-carrying capacity is achieved via strength checking. Finally, finite element analysis (FEA) is carried out to validate the proposed design, and experimental results demonstrate that the developed platform is capable of unbalance measurements with a high precision and resolution.

This paper concretely analyzes the change of landscape pattern of land use in Zhenlai Xian,Jilin Province.The analysis combines natural elements and humanistic elements.The information source is TM remote sensing image of 2000,2005 and 2009 in Zhenlai Xian.Through the interpretation of RS on small scales,this essay superimposes and analyzes the spatial data model established by GIS.Moreover,the paper calculates the landscape characteristic indexes of the spatial data model.The analysis shows that the area and number of landscape patches in research district changed obviously in the past ten years.The patch number of water landscape has increased substantially.The dynamic degree of different landscape area has changed enormously in study district.The area under cultivation has increased by a large margin while the areas of grassland and unused land have decreased by a large margin.In the study district,the fragmentation degree of landscape is lower.The fractal dimension of landscape is smaller and changes little.The heterogeneity of landscape is low.The landscape is relatively integrated.The ecology in this district shows obvious vulnerability and easy resilience.Three main driving forces affected the change of landscape pattern of land use in this district-restriction of natural environment,interference of human activities and policy direction.The three factors decide and affect the changing trend of landscape pattern.

Ion beam irradiation induces important biological effects and it is a long-standing task to acquire both qualitative and quantitative assessment of these effects. One effective way in the investigation is to utilize Fourier transformation infrared (FTIR) spectroscopy because it can offer sensitive and non-invasive measurements. In this paper a novel protocol was employed to prepare biomolecular samples in the form of thin and transversely uniform solid films that were suitable for both infrared and low-energy ion beam irradiation experiments. Under the irradiation of N+ and Ar+ ion beams of 25 keV with fluence ranging from 5?1015 ions/cm2 to 2.5?10 ions/cm2, the ion radio-sensitivity of four amino acids, namely, glycine, tyrosine, methionine and phenylalanine, were evaluated and compared. The ion beam irradiation caused biomolecular decomposition accompanied by molecular desorption of volatile species and the damage was dependent on ion type, fluence, energy and types of amino acids. The effectiveness of application of FTIR spectroscopy to the quantitative assessment of biomolecular damage dose effect induced by low-energy ion radiation was thus demonstrated.

Coastal wetlands are characterized by complex patterns both in their geomorphic and ecological features. Besides field observations, it is necessary to analyze the land cover of wetlands through the color infrared (CIR) aerial photography or remote sensing image. In this paper, we designed an evolving neural network classifier using variable string genetic algorithm (VGA) for the land cover classification of CIR aerial image. With the VGA, the classifier that we designed is able to evolve automatically the appropriate number of hidden nodes for modeling the neural network topology optimally and to find a near-optimal set of connection weights globally. Then, with backpropagation algorithm (BP), it can find the best connection weights. The VGA-BP classifier, which is derived from hybrid algorithms mentioned above, is demonstrated on CIR images classification effectively. Compared with standard classifiers, such as Bayes maximum-likelihood classifier, VGA classifier and BP-MLP (multi-layer perception) classifier, it has shown that the VGA-BP classifier can have better performance on highly resolution land cover classification.

The mutant effects of a keV range nitrogen ion (N+) beam on enzyme-producing probiotics were studied, particularly with regard to the induction in the genome. The electron spin resonance (ESR) results showed that the signal of ESR spectrum existed in both implanted and non-implanted spores, and the yields of free radicals increased in a dose-dependent manner. The ionic etching and dilapidation of cell wall could be observed distinctly through the scanning electron microscope (SEM). The mutagenic effect on genome indicated that N+ implantation could make base mutation. This study provided an insight into the roles low-energy ions might play in inducing mutagenesis of micro-organisms.

The Huolin River is one of the most important water sources for Xianghai wetland, Horqin wetland, and Chaganhu wetland in the western Songnen Plain of Northeast China. The annual runoff series of 46 years at Baiyun-hushuo Hydrologic Station, which is located in the middle reaches of the Huolin River, were analyzed by using wavelet analysis. Main objective was to discuss the periodic characteristics of the runoff, and examine the temporal patterns of the Huolin River recharging to the floodplain wetlands in the lower reaches of the river, and the corresponding effects of recharging variation on the environmental evolution of the wetlands. The results show that the annual runoff varied mainly at three time scales. The intensities of periodical signals at different time scales were strongly characterized by local distribution in its time frequency domain. The interdecadal variation at a scale of more than 30yr played a leading role in the temporal pattern of runoff variation, and at this scale, the runoff at Baiyunhushuo Hydrologic Station varied in turn of flood, draught and flood. Accordingly, the landscape of the floodplain wetlands presented periodic features, especially prominent before the 1990s. Compared with intense human activities, the runoff periodic pattern at middle (10–20yr) and small (1–10yr) scales, which has relatively low energy, exerted unobvious effects on the environmental evolution of the floodplain wetlands, especially after the 1990s.

Gongronella sp. JG was a fungal strain which expressed extracellular chitosanase of about 800 U/L during its growth in production medium. To improve its enzyme production, low energy N+ implantation was employed to mutate spores of JG. The implantation condition was optimized and the parameters of 15 keV and 60 × 2.6 × 1013 ions/cm2 were selected for further breeding experiments. A mutant designated as SG was obtained. It showed increased chitosanase production (1800 U/L) and shortened cultivation period (from 72 h to 60 h). Five-generation cultivation of SG indicated that its chitosanase production was stable at about 1800 U/L.

By combining geographic information system (GIS), a new conception of “group” in which covers the complex connected region is introduced in the paper. Based on the conception of group, a generalized Euler formula and its properties are deduced and proved. The paper also describes the mathematical principles of generating topological information of polygon in GIS maps and the methods for checking up the veracity of topological relations of the map with Euler formula and general Euler formula. We have also obtained the quantitative relations among real nodes, chains, islands and groups with the formulas. At the same time, the paper introduces Whole Sphere Stereographic (WSS) projection into the GIS, and defines a new conception of “sea”. The deduction of general Euler formula and the introduction of WSS projection to GIS have developed new ways of delineating GIS topological models from plane to sphere and even constructing three dimensional (3-D) topological models.

The progress of a microbeam facility in the Institute of Plasma Physics was discussed in this paper. This kind of equipment can supply single-particle beam which may be implanted into cells in micrometer-radius and measured by a new outstanding detector among global microbeam systems. Measurements by some plain targets showed that the highest current after the accelerator tube can be larger than 20 μA, the H+2 current before the second bending magnet is near 0.9 μA, the current after the second bending magnet is near 0.8 μA, and the current of the beam line (after a 2-mm diameter aperture) is near 0.25 nA which is enough for the single-particle microbeam experiment. It took scientists 3 months to do their microbeam experiment after setting up the accelerator beam line and get the microbeam from this equipment. Two pre-collimators were installed between the 2-mm diameter aperture and the collimator to survey the beam. Tracks on the CR39 film etched in the solution of NaOH showed that the beam can go through the collimator including a 10 μm diameter aperture and the 3.5 μm thick vacuum sealing film (Mylar). A new method, which is called optimization of the beam quality, was put forward in this paper, in order to get smaller diameter of beam-spot in microbeam system.

Using the methods of combining landscape ecology with GIS spatial analysis, this paper analyses the dynamics of the marsh landscape structure of the Sanjiang Plain in the past 20 years, furthermore, taking Fujin County, located in the north of the plain, as an example, analyzes the conversion between marsh and other land use types. It is shown that the marsh in the Sanjiang Plain decreased greatly in the past 20 years, but the trend has begun to reverse. The marsh area decreased by 51.33% from 1980 to 1996, whereas it decreased by 4.19% from 1996 to 2000. The fragmentation of the marsh increased; the number of the patches increased by 326 from 1986 to 1996, whereas it only increased by 18 patches from 1996 to 2000. It is obvious that the speed of patches number diminished and the marsh fragmentation decreased, which shows that the reclamation of the marsh converted from the fragmentation to the brim in a large area of the marsh. The reclaimed marsh has mainly converted to paddy field and dry land. Large-scale reclamation in the Sanjiang Plain influences its natural environment directly: the climate of the region turns from cold and wet to warm and dry, which makes the marsh both in the low-temperature northern part and in the deeply stagnant eastern part suitable for further agricultural development.

In view of the fact that ion implantation experiments had all been performed under vacuum state, a relative type ion stream-educing technique was designed for the injection of ion beam into organism and an ion stream-educing equipment was especially built for an electrostatic accelerator. A Monte-Carlo simulation method was used to model the penetrating energy and the change in ion path to justify its feasibility. The experimental results of the ion beam injection into Aspergillus.niger spore in combination with the results of CR-39 film have indicated that our technique is successful.

A radio frequency (r.f.) ion source used in the electrostatic accelerator was designed and built for the study on the ion beam bioengineering. The extracting characteristics were determined by experiments, from which the results showed that a maximal beam current is obtained under the condition of the extracting voltage 1700V and the gas pressure in the range of (4–8) × 10-4 Pa. And the diameter of the ion beam was measured as well.

Following the electron devices are widely used in daily life, Pb-free solder alloy, as the replacement of Pb solder joint material, needs extensive researches to observe the properties for using and simulation purpose. Solder are used as the joint to connect two work pieces in printed wiring board of electronics. Most lead-free solders comprise tin (Sn) as the majority component, and nominally pure b-Sn is the majority phase in the microstructure of these solders. The most important thing for solder joint that researchers care about is its life cycle. Due to the incomplete of the mechanical profile of Pb-free solder joint for now, this research worked on obtain data of life cycles. At the boundary of the Sn phase and Ag phase, the intermetallic would grow during the heating process, which affects the life cycle of the solder. This study incorporates mechanical testing and measurement of the intermetallic in scanning electron microscope (SEM) images in image J, to get enough data of life cycle to form a profile and the effects of the intermetallic. The measurement on images shows that the intermetalic layer grows in scallop-shape and the thickness increases with the temperature and sintering time. The growth rate can be modeled as a linear equation of the power of one half of the sintering time. This measurement will contribute to the ongoing research about the transit liquid phase sintering and the ball-grid array (BGA) reliability.

This article describes a new image decomposition strategy to use the GPU memory hierarchy architecture more efficiently. An image is decomposed into tiles and the size of each tile is determined based on the size of thread block. In order to avoid loading repeatedly tiles from global memory to shared memory, tiles must overlap each other. The parallel code is specifically tested with dilation operation, which is one of the basic operations in mathematical morphology. Significant performance increases on GPU-based computing platform are seen in some applications, demonstrating the advantage of the proposed parallel scheme.

This paper takes LAI which is the key state variable of crop as combination point, achieve the assimilation between ALMANAC and MODIS LAI using simulated annealing algorithm. Compared Actual yield and assimilated ALMANAC's output, the result shows that assimilation is a feasible way to yield estimation, the result also shows that the number of external data assimilation has great impact on simulation.

The collector for EUV source is one of the most important parts in EUV lithography system, which determines whether the whole EUV lithography can be used or not. Collection efficiency is the most important performance parameter and start point when designing a collector for EUV source. The main purpose of this research is to give the optical designers deep acquaintance with Wolter I collector and the designing direction. The collection efficiency with the approximate format of one mirror shell and whole collector in the most promising EUV collector-Wotler I collector is worked out and discussed in this paper. There is also the effect of collection efficiency and detailed processes when it acts the direction in the designing of Wolter I collector.

The last decade has witnessed a thriving development of the World Wide Web and internet networks, people are involved into different communication networks. With the increasing scale of these networks, it has left a challenge to understand their holistic features, to know which members and the relationships among them, that is, backbone, play vital roles. Based on data field theory, this paper proposes an algorithm that offers a practical procedure to extract backbone of large-scale networks. For dealing with the uncertainty of granularities of different backbones, we present a measurement to validate which is the optimal backbone with the most suitable granularity. We apply our method to the identical real-world networks and compare the results with several alternative backbone extracting methods. The experimental results illustrate that this backbone extraction algorithm can get a 0.8 score on precision ratios, and the recall ratios approximate reaches 0.5; the results are superior to the compared methods.

A new time-frequency analysis method of Hilbert-Huang Transform applied in Pipeline leak detection is proposed. Choosing the negative pressure wave signal from dynamic pressure transmitter as research object, the dynamic pressure signal is decomposed by the empirical mode decomposition, and we obtain the proper mode functions that satisfy the condition. The propagation time difference is detected accurately. Then, negative pressure wave signals are processed by Hilbert-Huang transformation method, so as to realize the accurate location of pipeline leak point. The results of experiment show that the new approach can improve the accuracy of detection and location of pipeline leak point.

Canny Arithmetic Operator has been proved to be a traditional operator possessing a better detective effect in the common usage of edge detection algorithm currently. However, Canny Operator also has certain deficiencies, such as choices of dimensions and Threshold Limit Values. When the dimension is bigger, effect of noise to the edge is smaller, but the locating accuracy will be lost. Whereas, when the dimension is smaller, the locating accuracy will be high, but the ratio of Signal-to-Noise of output image will be lower. In the meantime, using a same Threshold Limit Values (TLV) in the whole image would also influence the edge detection in dissimilar districts. This paper presents an improved algorithm to the edge detection, which uses image pyramid theories to improve the Canny Operator. It is also demonstrated in this study that this method can rectify the shortage perfectly, and obtain a more ideal edge image.

Human auditory has non-linear characteristics, while wavelet packet transform (WPT) has flexible analysis ability to time-frequency property so that it is more compatible to simulate the human auditory model. In this paper, human auditory model is analyzed, after which a new algorithm for speech enhancement using node-threshold wavelet packet transform based on bark-scaled decomposition is established, multi-resolution singular spectral entropy method is applied to estimate the node noise, and uses soft threshold to deal wavelet transform coefficient. The experiments show that this algorithm is valid on various noise conditions, especially for color noise and non-stationary noise conditions.

In this paper, a near-optimal and robust SEDC (supplemental excitation damping control) has been developed for damping SSR (subsynchronous resonance) in Shangdu power plant in China . This paper first gives a brief analysis of the multi-mode SSR in Shangdu system, and then provides the configuration of SEDC to provide damping for all SSR modes. The primary contribution of this paper lies in the presented method GASA, in which GA (genetic algorithm) and SA (simulated annealing) are combined to solve the SEDC optimal parameter-searching problem. The details of this approach are presented, and the performance of the SEDC obtained by GASA is verified with the Shangdu system through eigenvalue analysis and electromagnetic simulations.

Based on ETM+ remote sensing image, according to geographical distribution and spectral characteristics of saline-alkalized land, especially that of light, and moderate saline-alkalized land, an algorithm of semi-supervised multi-grade mean weighed seed region searching is presented. Experimental results indicate that the algorithm has high operation speed, high segmentation accuracy and certain fault tolerance, and also, to a great extent, over-segmentation problem can be perfectly solved. But because of mixed distribution of sand land and saline-alkalized land, they can not be effectively segmented by the algorithm.

The choice of delay time and embedding dimension have no correlation in the process of phase-space reconstruction. Based on this principle, a new idea for determining the embedding dimension is proposed. It uses CAO theory after determining the delay time by the mutual information function. Numerical simulations show that the method is applicable for determining the appropriate delay time and the best embedding dimension. The method can recover the original phase space from the time series effectively, and can be used as an effective method to identify the chaotic signal.

Ecosystem services are premises for human beings to exist and develop in the world, and it is of importance to study effects of land use change on ecosystem functions. Songnen plain, located in Northeast China, is one of the national key bases for agricultural production. Because there were remarkable variations in land use in recent years, it can supply specific foundation for protection and restoration of regional eco-environment to explore changes in its values of ecosystem services. This study aims to qualify long-term changes in land use of Songnen plain from 1980 to 2000, and to explore the impact of land use change on ecosystem services. With 2-period land use data using RS and GIS, this paper analyzed changes in land use and in ecosystem service values using the ecosystem service value coefficients (VC) put forward by Costanzaet al. Results showed that from 1980 to 2000, area of rangeland, water area and wetlands and area of cropland decreased, but urban area and unused land increased. Due to cropland’s comparatively low VC and comparatively high VC of wetlands and water area, increment in cultivated land could not offset the total decrement in regional ecosystem service values because of the decrease in area of wetlands and water area. Meanwhile, city sprawl has also led to loss of ecological values. Total ecosystem service values of the study area reduced dramatically, from 34,926.10 × 106$ to 31,744.54 × 106$ in the period 1980-2000. This represents a 9.11% net decline in annual value of ecosystem services in the study area.

A. "The ballistic-range of the flight line" is important current installation facilities for aerodynamic and ballistics in many countries. There are a tens of flash orthographical shadow photograph points which are the main test equipments in the ballistic range of the flight line. The tests shows, there can be 3 us unsychroniged intervels between the two-flashes at same photographical point. It could result in unnegligible measurement error. therefor. the synchronism of orthographical photography should be improved. B. One flash light source was divided as two orthographic flash lightsources by the "Y" optical fiber bundle with optical coupled devices. On this way, it not only has kept flash light synchronism strictly, but also simplified the optical structure-decreased in number of flash light sources. and improved the quality of photographes. The preliminary tests with the pockets showed that the optical fiber synchronization technic got satisfactory results. C. It is important to pay attention on the light transfer efficieney, the characteristics of point light sources and its symmetry, so that, the flash shadow photography is ever satisfified with light splitting sources, the spectrophotometric characteristics of flare light sources transmission rates of optical fibers for different band. numerical aperture. size and structure of optical devices size and place of the light source image. the terminal section size:and arrangement of fiber optical branches ect. All of those are important considering factors for designing optical coupled devices, fiber optical branches and choosing optical fiber materials.

Land cover classification is the core of converting satellite imagery to available geographic data. However, spectral signatures do not always provide enough information in classification decisions. Thus, the application of multi-source data becomes necessary. This paper presents an evidential reasoning (ER) approach to incorporate Landsat TM imagery, altitude and slope data. Results show that multi-source data contribute to the classification accuracy achieved by the ER method, whereas play a negative role to that derived by maximum likelihood classifier (MLC). In comparison to the results derived based on TM imagery alone, the overall accuracy rate of the ER method increases by 7.66% and that of the MLC method decreases by 8.35% when all data sources (TM plus altitude and slope) are accessible. The ER method is regarded as a better approach for multi-source image classification. In addition, the method produces not only an accurate classification result, but also the uncertainty which presents the inherent difficulty in classification decisions. The uncertainty associated to the ER classification image is evaluated and proved to be useful for improved classification accuracy. Refereed/Peer-reviewed