Estimation-free spatial-domain image reconstruction of structured illumination microscopy

Structured illumination microscopy(SIM)achieves super-resolution(SR)by modulating the high-frequency information of the sample into the passband of the optical system and subsequent image reconstruction.The traditional Wiener-filtering-based reconstruction algorithm operates in the Fourier domain,it requires prior knowledge of the sinusoidal illumination patterns which makes the time-consuming procedure of parameter estimation to raw datasets necessary,besides,the parameter estimation is sensitive to noise or aberration-induced pattern distortion which leads to reconstruction artifacts.Here,we propose a spatial-domain image reconstruction method that does not require parameter estimation but calculates patterns from raw datasets,and a reconstructed image can be obtained just by calculating the spatial covariance of differential calculated patterns and differential filtered datasets(the notch filtering operation is performed to the raw datasets for attenuating and compensating the optical transfer function(OTF)).Experiments on reconstructing raw datasets including nonbiological,biological,and simulated samples demonstrate that our method has SR capability,high reconstruction speed,and high robustness to aberration and noise.

Ultrafast dynamics of femtosecond laser-induced high spatial frequency periodic structures on silicon surfaces

Femtosecond laser-induced periodic surface structures(LIPSS)have been extensively studied over the past few decades.In particular,the period and groove width of high-spatial-frequency LIPSS(HSFL)is much smaller than the diffraction limit,making it a useful method for efficient nanomanufacturing.However,compared with the low-spatial-frequency LIPSS(LSFL),the structure size of the HSFL is smaller,and it is more easily submerged.Therefore,the formation mechanism of HSFL is complex and has always been a research hotspot in this field.In this study,regular LSFL with a period of 760 nm was fabricated in advance on a silicon surface with two-beam interference using an 800 nm,50 fs femtosecond laser.The ultrafast dynamics of HSFL formation on the silicon surface of prefabricated LSFL under single femtosecond laser pulse irradiation were observed and analyzed for the first time using collinear pump-probe imaging method.In general,the evolution of the surface structure undergoes five sequential stages:the LSFL begins to split,becomes uniform HSFL,degenerates into an irregular LSFL,undergoes secondary splitting into a weakly uniform HSFL,and evolves into an irregular LSFL or is submerged.The results indicate that the local enhancement of the submerged nanocavity,or the nanoplasma,in the prefabricated LSFL ridge led to the splitting of the LSFL,and the thermodynamic effect drove the homogenization of the splitting LSFL,which evolved into HSFL.

Drivers of spatial structure in thinned forests

Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importance of structure-based.Aims:Our objectives were to define the direction of structure-based forest management.Subsequently,we investigated the relationships between forest structure and the regeneration,growth,and mortality of trees under different thinning treatments.Ultimately,the drivers of forest structural change were explored.Methods:On the basis of 92 sites selected from northeastern China,with different recovery time (from 1 to 15years) and different thinning intensities (0–59.9%) since the last thinning.Principal component analysis (PCA)identified relationships among factors determining forest spatial structure.The structural equation model (SEM)was used to analyze the driving factors behind the changes in forest spatial structure after thinning.Results:Light thinning (0–20%trees removed) promoted forest regeneration,and heavy thinning (over 35% of trees removed) facilitated forest growth.However,only moderate thinning (20%–35%trees removed) created a reasonable spatial structure.While dead trees were clustered,and they were hardly affected by thinning intensity.Additionally,thinning intensity,recovery time,and altitude indirectly improve the spatial structure of the forest by influencing diameter at breast height (DBH) and canopy area.Conclusion:Creating larger DBH and canopy area through thinning will promote the formation of complex forest structures,which cultivates healthy and stable forests.

Numerical Simulation of Super-Resolution Structured Illumination Microscopy (SIM) Using Heintzmann-Cremer Algorithm with Non-Continuous Spatial Frequency Support

We report a comprehensive numerical study of super resolution (SR) structured illumination microscopy (SIM) utilizing the classic Heintzmann-Cremer SIM process and algorithm. In particular, we investigated the impact of the diffraction limit of the underlying imaging system on the optimal SIM grating frequency that can be used to obtain the highest SR enhancement with non-continuous spatial frequency support. Besides confirming the previous theoretical and experimental work that SR-SIM can achieve an enhancement close to 3 times the diffraction limit with grating pattern illuminations, we also observe and report a series of more subtle effects of SR-SIM with non-continuous spatial frequency support. Our simulations show that when the SIM grating frequency exceeds twice that of the diffraction limit, the higher SIM grating frequency can help achieve a higher SR enhancement for the underlying imaging systems whose diffraction limit is low, though this enhancement is obtained at the cost of losing resolution at some lower resolution targets. Our simulations also show that, for underlying imaging systems with high diffraction limits, however, SR-SIM grating frequencies above twice the diffraction limits tend to bring no significant extra enhancement. Furthermore, we observed that there exists a limit grating frequency above which the SR enhancement effect is lost, and the reconstructed images essentially have the same resolution as the one obtained directly from the underlying imaging system without using the SIM process.

The Study on the Evolution of Urban Spatial Structure in Zhuhai City Based on Spatial Syntax

With the deepening of the Guangdong-Hong Kong-Macao Greater Bay Area strategy and the accelerated integration and development of the east and west sides of the Pearl River Estuary,Zhuhai’s hub position is becoming more and more prominent.The city of Zhuhai has a dense water network and is divided into two urban areas,the east and the west,under the influence of the Mordor Gate waterway.Based on the theory of spatial syntax,this paper carries out an analytical study on the urban spatial structure of Zhuhai,identifies the distribution characteristics of urban POIs,and provides theoretical support for the urban development of Zhuhai.

A Discussion on the Structure and Spatial Composition of Long Museum West Bund

The Long Museum,with its distinctive T-shaped“umbrella-vault”structure,offers a rich array of spatial experiences.This article delves into space from both structural and compositional perspectives.As the construction mediator,the umbrella vault embodies the consistency of construction and implies the causality of the surface.Presented as an element,the space flows freely,showing diverse fields and order.In terms of the liberation of its meaning,the space offers static perception and dynamic experience,creating a rich exhibition atmosphere.As a distinct entity,the umbrella-vault presents the physical nature,and the dialogue between the Long Museum and the city makes it a museum of art for the people.

Spatial structure evolution of overlying strata and inducing mechanism of rockburst in coal mine

Spatial structure of overlying strata existed and evolved dynamically with the exploitation scope （boundary conditions） changes in coal mines and to induce rockburst. Based on the“key strata”theory, the integrated spatial structure of overlying strata was put forward, which was composed of “O-X” structure in the plane section and “F” structure in the vertical section. The formation and ongoing instability of the“O-X”and“F”structures were called as dynamic evolution cycle of the overlying strata. Three basic categories of “O-X”, “F” and “T” structures were defined, and the strata behaviors of each spatial structure were analyzed. According to energy theory, mechanism of rockburst induced by spatial structure instability was discussed. The research expanded the scope of traditional ground pressure theory and provided a guide for the prevention of rockburst and mining tremors induced by structure instability of overlying

Phytoplankton Community Structure and Its Spatial Distribution along Anhui-Jiangsu Reaches of the Yangtze River in Autumn 2009

[Objective] Surveys of phytoplankton were taken during the autumn of 2009 along Anhui-Jiangsu reaches of the Yangtze River to understand the species com- position and their spatial distributions. [Method] Phytoplankton species, their quanti- ties, biomass and the Mcnaughton＇s dominance indices were all measured and their spatial distribution characteristics were determined using cluster analysis. [Result] There were 27 species, belonging to 5 phyla, namely Chlorophyta, Bacillariophyta, Cyanophyta, Euglenophyta and Cryptophyta, of phytoplankton collected and identified from the surveys. Results showed that Bacillariophyta was the predominant phyto- plankton with 16 species collected which accounted for 59.3% of the total species identified. The number of species collected belonging to Chlorophyta, Cyanophyta, Cryptophyta and Euglenophyta were 6, 2, 2, and 1, accounting for 22.2%, 7.4%, 7.4% and 3.7% of the total number identified, respectively. At the species level, the predominant species were Fragilaria crotonensis, Melosira italica, Navicula crypto- cephala, Cyclotella striata and Chroomonas acuta. Phytoplankton abundance was ranging from 5.68×10^4 to 7.08×10^4 cells/L with its average of 6.01×10^4 cells/L. Phyto- plankton biomass was ranging from 30.43 to 34.73 μg/L with its average of 32.46 μg/L. Compared with the previous reports, the number of phytoplankton species was decreased but its abundance and biomass was increased along the Jiangsu reach of the Yangtze River. However, Bacillariophyta species were still the predominant species and the phytoplankton community structure had not significantly changed from the previous studies. [Conclusion] These results might be explained as that the water quality in the Yangtze River was deteriorated but had not come to the worst. The results of similarity analysis gave two clusters of phytoplankton community as Nanjing, Wuhu and Jiangyin sampling sites were clustered into one group and Tongling and Anqing were clustered into another group.

Study upon the Spatial Structure of Regional Eco-tourism-Based upon the Perspective of Supply and Demand and Competition Field

Along with the coming of the low-carbon era, people have paid more and more attention to the natural environment and eco-tourism will embrace a huge development. From the perspectives of the market relationship of supply-demand in economics and of field competition in physics, this paper has discussed upon the present status of the spatial structure of eco-tourism, and analyzed the relationship between supply-demand and field, in order to clarify the direction for the balance between supply and demand in the field and to guide eco-tourism to the way of sustainable development.

Study on Spatial Structure of Rural Tourism in Wuhan Urban Agglomerations

Spatial structure of rural tourism in the urban agglomerations of Wuhan was analyzed by comprehensively studying relevant documents about rural tourism,and reviewing previous researches on the concept and spatial structure of rural tourism.Through investigating rural tourist resources in the study area,resource advantages and characteristics of 9 cities were introduced,and the Gini Coefficient was taken to quantitatively analyze spatial patterns of its rural tourist villages,the obviously imbalanced concentration of these villages was pointed out.By measuring connectivity and accessibility of regional spaces in the study area,its traffic connectivity was proved moderate,and accessibility of each tourist village and town was fine.Then an optimized spatial structure was proposed for the rural tourism development in Wuhan Urban Agglomerations,that is,"one core,one belt and three districts".

Study on Spatial Structure and Response of Towns and Villages System——with Dongzhai Town in Ningwu County of Shanxi Province as a Study Case

Taking Dongzhai Town in Ningwu County of Shanxi Province as example, this essay explores the spatial structure of towns and villages system from the following perspectives: scale structure, function structure, structural characteristics of village land-use, and spatial distribution characteristics of Dongzhai villages. There are 5 grades of villages according to their scales, that is, villages have a population over 1 000, between 500 and 1 000, between 100 and 500, less than 100, less than 50. The function structure of Dongzhai Town is divided into 3 grades, Grade 1 (core village), is village with such functions as tourist service, transportation and distribution function. Grade 2 (characteristic village), is agricultural settlement with functions such as industrial function, transportation service, tourist service, and forestry function. Grade 3 (general village), is agricultural settlements with prominent agricultural functions (dry farming). This essay also predicts the change and responses of this town based on the population forecast models. It is predicted that the population of Jiancheng District will reach 4 750 in 2010, 6 400 in 2015, 8 700 in 2020. Returning farmland to forests in Fenhe River valley can ensure the conservation of water resources and the development of tourist service. The proportion of forest land, especially bushes land, and proportion of grassland, especially artificial grass will increase dramatically. The number of slope land will be down a bit. The Lands for settlement and transportation will increase with the development of ecological migration and tourist service. Specialized land such as water area and places of interest will skyrocket. Village patterns and spatial distribution under the system of towns and villages will be improved as well.

Topology Structure Synthesis and Analysis of Spatial Pyramid Deployable Truss Structures for Satellite SAR Antenna

Many attentions for structural synthesis are paid to planar linkages and parallel mechanisms, while design novel pyramid deployable truss structure（PDTS） of satellite SAR mainly depends on experience of designer. To design novel configuration of PDTS, a two-step topology structure synthesis and analysis approach is proposed. Firstly, a conceptual configuration of PDTS is synthesized. Weighted graph and weighted adjacency matrix are established to realize topological description for PDTS. Graph properties are then summarized to distinguish differentia between PDTS and other type structures. According to graph properties, a procedure for synthesis conceptual configuration of PDTS is presented. Secondly, join relationship of components in a PDTS is analyzed. Kinematic chain and corresponding incidence/adjacency matrix are employed to analyze join relationship of PDTS. Properties and simplified rules of kinematic chain are extracted to construct kinematic chain. A procedure for construction kinematic chain of PDTS is then established. Finally, with this two-step approach all 11 rectangular pyramid deployable structures whose folded state is planar are discovered and their kinematic chains are constructed. Based on synthesis results, a novel deployable support structure for satellite SAR is designed. The proposed research can be applied to obtain some novel PDTSs, which is of great importance to design some novel deployable support structures for satellite SAR antenna.

Seismic isolation analysis of FPS bearings in spatial lattice shell structures

A theoretical model of a friction pendulum system （FPS） is introduced to examine its application for the seismic isolation of spatial lattice shell structures. An equation of motion of the lattice shell with FPS bearings is developed. Then, seismic isolation studies are performed for both double-layer and single-layer lattice shell structures under different seismic input and design parameters of the FPS. The influence of frictional coefficients and radius of the FPS on seismic performance are discussed. Based on the study, some suggestions for seismic isolation design of lattice shells with FPS bearings are given and conclusions are made which could be helpful in the application of FPS.

Anomaly Models of Spatial Structures for Copper-Molybdenum Ore Deposits and their Application

This paper discusses the enrichment and depletion regularities for porphyry coppermolybdenum ore deposits in different regions and varied deposit genetic types in the same area, taking three porphyry copper-molybdenum ore deposits （i.e., the Chengmenshan in Jiangxi, Wunugetushan in Inner Mongolia, Baishantang in Gansu） and two copper deposits in Gansu Province （the Huitongshan skarn deposit and Gongpoquan composite deposit） as case studies. The results show that porphyry Cu-Mo deposits or skarn copper deposits include both enrichment of the ore-forming elements and associated elements, and depletion of some lithophile dispersed elements, rare earth elements （REE） and some major elements. And the depleted elements vary with deposits, having generality and their own features. On a deposit scale, the positive anomalies of enriched elements and negative anomalies of depleted elements follow in a sequence to comprise regular anomaly models of spatial structures. The exploration in the Tongchang deposit in Jiangxi and Huitongshan deposit in Gansu suggests that anomaly models play a key role in the identification of mineral occurrences and deposits compared to one single enriched element anomaly. And the anomaly models exert a critical effect on the optimization of prospecting targets and their potential evaluation.

Community structure and spatial distribution of macrobenthos in the shelf area of the Bering Sea

Field investigations of marine macrobenthos were conducted at ten sites in the Bering Sea in July 2010. Altogether 90 species of macrobenthos belonging to 59 families and 78 genera were identified. Among them, 41 polychaetes, 16 mollusks, 23 crustaceans, three echinoderms, two cnidarians, one nemertean, one priapulid, two sipunculids, and one echiuran were identified. The average density and biomass of total macrobenthos were 984 ind./m2 and 1207.1 g/ma of wet weight, respectively. The predominant species in the study area were Scoloplos armiger, Eudorella pacifica, Ophiura sarsii, Heteromastus filiformis, Ennucula tenuis, and Harpiniopsis vadiculus by abundance, while the predominant species in this area was Echinarachnius parma by biomass. Hierarchical cluster analysis （Bray-Curtis similarity measure） revealed that two impor- tant benthic assemblages in the study area were CommunityA and Community B. CommunityA was stable and Community B was unstable, as shown by the Abundance/Biomass Comparisons （ABC） approach. The macrobenthic community structure in the shelf of the Bering Sea was characterized by its high abundance and biomass, high productivity but great heterogeneity.

An experimental study of the spatial structures of the instabilities of longshore currents on plane beaches

A laboratory experiment on alongshore currents is conducted for two plane beaches with slopes 1：40 and 1：i00 to investigate the instability of alongshore currents. The dye release experiment is also performed synchronously in surf zone. Complicated and strongly unstable motions of alongshore currents are observed in the experiment. To examine the spatial and temporal variations of the shear instabilities of longshore clearly, dye batches are released in surf zone. The deformation of the dye patch is observed efficiently and effectively with charge coupled device （CCD） system. Some essential characteristics of the shear instability are validated from the results of image analyses of the temporal variation of the dye patch. The influences of alongshore currents, Stokes drift, large-scale vorticity and the shear instabilities on the transport of dye are analyzed using the collected images. The spatial structure of the instabilities of longshore currents is studied by analyzing collected images of the dye patch. And the phase velocity of the meandering movements is obtained through measuring the movement distances of the oscillations of dye patch in alongshore direction with time. The results suggest that the propagation speed of the shear instability is approximately 5070 7570 of maximum of mean alongshore currents for irregular and regular waves. The calculated propagation speed using a linear instability analysis theory is compared with the experimental results. The comparison shows agreements between them.

SPATIAL STRUCTURE EVOLUTION OF SYSTEM OF RECREATION BUSINESS DISTRICT——A Case of Suzhou City

The growing attention on urban tourism was very widespread. There are two angles to study urban tourism: supply-side and demand-side. And the supply-side of the tourism remains very important. The RBD (Recreation Business District) is a useful framework to understand the components of urban tourism and how they fit together. The paper begins with a review on the RBD and the spatial structure of tourism in urban areas and then attempts to develop a more general understanding of the spatial structure evolution of RBDs in a tourist-historic city-Suzhou. The spatial structures and functions of the RBDs in Suzhou are examined, based on field observations, interviews with city officials and industry leaders, and a review of available documents. The urban tourism of Suzhou has developed in a range of contexts, that various types of RBDs have emerged as a result of different urban development strategies. The spatial structure has evolved from the past "Single-cored Structure" to "Double-cored Structure" at present, and then to "Chain Structure" in the future. The spatial form and evolution of RBD in Suzhou are closely relative with its urban spatial expansion. Urban area dispersal is the prerequisite of the emergence of the RBD. Planning and constructing the RBD becomes a new impetus to urban growth or renewal. Finally, a number of strategies for planning and developing the RBD in Suzhou are suggested. The different RBDs should adopt different strategies. Intensification can be the possible strategy for the RBDs in the ancient city. Accreting with the urban theme park or engrafting on the Jinji Lake is suggested respectively for the RBD in the Suzhou New District and the Suzhou Industrial Park.

Strength failure of spatial reticulated structures under multi-support excitation

Under strong earthquakes, long-span spatial latticed structures may collapse due to dynamic instability or strength failure. The elasto-plastic dynamic behaviors of three spatial latticed structures, including two double-layer cylindrical shells and one spherical shell constructed for the 2008 Olympic Games in Beijing, were quantitatively examined under multi-support excitation （MSE） and uniform support excitation （USE）. In the numerical analyses, several important parameters were investigated such as the peak acceleration and displacement responses at key joints, the number and distribution of plastic members, and the deformation of the shell at the moment of collapse. Analysis results reveal the features and the failure mechanism of the spatial latticed structures under MSE and USE. In both scenarios, the double-layer reticulated shell collapses in the ＂overflow＂ mode, and the collapse is governed by the number of invalid plastic members rather than the total number of plastic members, beginning with damage to some of the local regions near the supports. By comparing the numbers and distributions of the plastic members under MSE to those under USE, it was observed that the plastic members spread more sufficiently and the internal forces are more uniform under MSE, especially in cases of lower apparent velocities in soils. Due to the effects of pseudo-static displacement, the stresses in the members near the supports under MSE are higher than those under USE.

Spatial structure optimization of mountainous abandoned mine land reuse based on system dynamics model and CLUE-S model

The mountainous abandoned mine land is often distributed in the fomi of fragmented patches. Therefore, it can greatly promote the reuse value of abandoned mine land and relieve the pressure of land demand to realize the rational reuse of abandoned mine land based on the future land use structure and spatial layout of mountainous area. In this paper, optimization of the spatial structure of mountainous abandoned mine land reuse is realized through the system dynamics model and CLUE-S model. Mentougou district, Beijing, China is selected as the research area. System dynamics model with feedback functions is constructed to simulate land use structure from 2011 to 2025, which is taken as the quanfiiative constraint on spatial structure optimization. CLUE-S model with neighborhood analysis function is applied to simulate future land use spatial structure. The simulation result layer is superimposed with the abandoned mine land distribution layer and the optimized spatial structure of abandoned mine land reuse then is determined, checked by reuse suitability evaluation. The result shows that abandoned mine land can be fully optimized as other land use types according to demand, and the reuse directions are water conservancy facilities land, urban land, rural residential land, tourism land, garden land, woodland and grassland. The trend of abandoned mine land reuse tend to be consistent with land use types of neighboring patches. This study can provide theoretical reference for the practices of mountainous abandoned mine land reuse.

Spatial pattern analysis for quantification of landscape structure of Tadoba-Andhari Tiger Reserve,Central India

Landscape structure is often regarded as an important factor that governs the distribution and abundance of species. Therefore it is critical to understand the landscapes and their dynamics. Patterns of landscape elements strongly influence the ecological characteristics. This study was designed to document and map the current status of the tropi-cal dry deciduous forest of the Tadoba-Andhari Tiger Reserve （TATR）, Central India, （using IRS P6 LISS IV data） and to describe its landscape structure at three levels of organization viz. landscape, class, and patch. The study area was classified into 10 land cover classes that include 6 vegetation classes. The landscape structure was analyzed using FRAG-STATS using 12 set of indices. The TATR landscapes have a total of 2,307 patches with a mean patch size of 25.67 ha and patch density of 1.7 patches per km2. Amongst all land cover classes, mixed bamboo forest is dominant-it occupied maximum area （77.99%）-while riparian forest is least represented （0.32%）. Mixed forest has maximum number of patches among all vegetation classes. Results have shown that despite being dominant in the area, mixed bamboo forest has low patch density （0.25/100 ha）. Dominance of mixed bamboo forest is attributed to large patch sizes and not to the number of patches. This study has focussed on the approach of integrating satellite forest classification and forest inven-tory data for studying forest landscape patterns.