Asperfilasin A(1),featuring a unique 5/5 cyclopenta[c]pyrrol-one bicyclic core,represents a newly discovered skeletal cytochalasan isolated from Aspergillus flavipes.The enantioselective total synthesis was efficientl...Asperfilasin A(1),featuring a unique 5/5 cyclopenta[c]pyrrol-one bicyclic core,represents a newly discovered skeletal cytochalasan isolated from Aspergillus flavipes.The enantioselective total synthesis was efficiently accomplished from the key intermediate(S)-6 with three contiguous stereocenters in 5 steps and the synthetic 1 induced G2/M-phase cell cycle arrest of HT29 cells and apoptosis of HL60 and NB4 cells by activation of caspase-3 and degradation of PARP.(S)-6,bearing three contiguous chiral centers,was efficiently constructed by a novel Nazarov cyclization reaction containing basic nitrogen,which was less developed,primarily due to the incompatibility of basic nitrogen under acidic reaction conditions.This reaction allows a wide range of pentadienone substrates containing basic nitrogen to undergo Nazarov cyclization in a single regioselective and diastereoselective manner and is capable of generating three stereocenters simultaneously.Furthermore,the mechanism of the Nazarov cyclization and the origin of the regio-and diastereoselectivity were elucidated by DFT calculations and deuteration experiments,providing valuable insights into the reaction and serving as a guide for future applications involving substrates containing basic nitrogen.展开更多
Norvin Richards’new book Contiguity Theory counts as an important contribution to the study of syntax-phonology interaction.In this book,Richards departs from the standard Minimalist approach which attends to syntact...Norvin Richards’new book Contiguity Theory counts as an important contribution to the study of syntax-phonology interaction.In this book,Richards departs from the standard Minimalist approach which attends to syntactic differences of movement among languages by just positing the diacritic features in some languages,but not in others.He instead rationalizes a set of fundamental principles like Affix Support and Generalized Contiguity,grounded in independent and observable properties of languages.While these principles must be universally satisfied,languages tend to use different mechanisms to realize this goal under the constraint of their own phonological and morphological properties.The different ways employed may thus yield cross-linguistic variations concerning the presence or absence of syntactic movements.Richards’book makes a serious attempt to explore the syntactic variations among languages by taking an interface-oriented approach,with far-reaching implications for understanding how modules interact with each other within the current theory of grammar and accounting for the syntactic variations among various languages.展开更多
The 3D reconstruction pipeline uses the Bundle Adjustment algorithm to refine the camera and point parameters. The Bundle Adjustment algorithm is a compute-intensive algorithm, and many researchers have improved its p...The 3D reconstruction pipeline uses the Bundle Adjustment algorithm to refine the camera and point parameters. The Bundle Adjustment algorithm is a compute-intensive algorithm, and many researchers have improved its performance by implementing the algorithm on GPUs. In the previous research work, “Improving Accuracy and Computational Burden of Bundle Adjustment Algorithm using GPUs,” the authors demonstrated first the Bundle Adjustment algorithmic performance improvement by reducing the mean square error using an additional radial distorting parameter and explicitly computed analytical derivatives and reducing the computational burden of the Bundle Adjustment algorithm using GPUs. The naïve implementation of the CUDA code, a speedup of 10× for the largest dataset of 13,678 cameras, 4,455,747 points, and 28,975,571 projections was achieved. In this paper, we present the optimization of the Bundle Adjustment algorithm CUDA code on GPUs to achieve higher speedup. We propose a new data memory layout for the parameters in the Bundle Adjustment algorithm, resulting in contiguous memory access. We demonstrate that it improves the memory throughput on the GPUs, thereby improving the overall performance. We also demonstrate an increase in the computational throughput of the algorithm by optimizing the CUDA kernels to utilize the GPU resources effectively. A comparative performance study of explicitly computing an algorithm parameter versus using the Jacobians instead is presented. In the previous work, the Bundle Adjustment algorithm failed to converge for certain datasets due to several block matrices of the cameras in the augmented normal equation, resulting in rank-deficient matrices. In this work, we identify the cameras that cause rank-deficient matrices and preprocess the datasets to ensure the convergence of the BA algorithm. Our optimized CUDA implementation achieves convergence of the Bundle Adjustment algorithm in around 22 seconds for the largest dataset compared to 654 seconds for the sequential implementation, resulting in a speedup of 30×. Our optimized CUDA implementation presented in this paper has achieved a 3× speedup for the largest dataset compared to the previous naïve CUDA implementation.展开更多
Effect of Mo and Mo2 C on the microstructure and properties of Ti（C,N）-based cermets was investigated in this article. The results have indicated that the weight percentage of Mo from 5 to 10 can reduce Ti（C,N） gr...Effect of Mo and Mo2 C on the microstructure and properties of Ti（C,N）-based cermets was investigated in this article. The results have indicated that the weight percentage of Mo from 5 to 10 can reduce Ti（C,N） grain diameter and thickness of the rim, and Ti（C,N） grain can be wetted by Ni-Cu-Mo liquid so as to get small contiguity of Ti（C,N） grain. In that way, the transverse rupture strength of Ti（C,N）-based cermets has reached 1800-1900 MPa; the fracture toughness has been due to 16-18 MPa.m1/2. But 15 wt pct Mo was not more effective on Ti（C,N）-based cermets, because the thickness of the rim becomes larger. In the circumstance of Mo2 C, 5 wt pct Mo2 C was good for microstructure and properties of Ti（C,N）-based cermets, but 11 wt pct Mo2C has resulted in larger contiguity of Ti（C,N） grain and big Ti（C,N） grain diameter so as to reduce transverse rupture strength and fracture toughness. So that, the effect of Mo on Ti（C,N）-based cermets is better than Mo2C.展开更多
The aim of this research was to examine the effect of microstructural parameters on the tensile properties of different compositions of tungsten heavy alloys. The microstructural parameters （grain size, connectivity,...The aim of this research was to examine the effect of microstructural parameters on the tensile properties of different compositions of tungsten heavy alloys. The microstructural parameters （grain size, connectivity, contiguity, and solid volume fraction） were measured and were found to have a significant effect on the tensile properties of tungsten-based heavy alloys. The microstructural parameters of W-Ni-Fe alloys are sufficiently different to present a range of mechanical properties. It is concluded that the mechanical properties of tungsten heavy alloys largely depend on the microstructural parameters and their ductility is particularly harmed when grains are contiguous.展开更多
Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased est...Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased estimator of variance does not exist for this design.Oftentimes,a quasi-default estimator applicable to simple random sampling(SRS)is used,even if it carries with it the likely risk of overestimating the variance by a practically important margin.To better exploit the precision of systematic sampling we assess the performance of five estimators of variance,including the quasi default.In this study,simulated systematic sampling was applied to artificial populations with contrasting covariance structures and with or without linear trends.We compared the results obtained with the SRS,Matern’s,successive difference replication,Ripley’s,and D’Orazio’s variance estimators.Results:The variances obtained with the four alternatives to the SRS estimator of variance were strongly correlated,and in all study settings consistently closer to the target design variance than the estimator for SRS.The latter always produced the greatest overestimation.In populations with a near zero spatial autocorrelation,all estimators,performed equally,and delivered estimates close to the actual design variance.Conclusion:Without a linear trend,the SDR and DOR estimators were best with variance estimates more narrowly distributed around the benchmark;yet in terms of the least average absolute deviation,Matern’s estimator held a narrow lead.With a strong or moderate linear trend,Matern’s estimator is choice.In large populations,and a low sampling intensity,the performance of the investigated estimators becomes more similar.展开更多
In the paper in order to ascertain the condition of the right-bank of the dam at the Vilyui hydroelectric power plant measurements are applied to obtain experimentaldate such as drilling borehole, hydrolocationand so ...In the paper in order to ascertain the condition of the right-bank of the dam at the Vilyui hydroelectric power plant measurements are applied to obtain experimentaldate such as drilling borehole, hydrolocationand so forth. By finding out the distribution of the temperature field some corresponding measures are taken to improve the stability of the dam during the change of the ground temperature. And finally some conclusions are draw to the study.展开更多
In the realm of Bounded Topology we now consider supernearness spaces as a common generalization of various kinds of topological structures. Among them the so-called Lodato spaces are of significant interest. In one d...In the realm of Bounded Topology we now consider supernearness spaces as a common generalization of various kinds of topological structures. Among them the so-called Lodato spaces are of significant interest. In one direction they are standing in one-to-one correspondence to some kind of topological extensions. This last statement also holds for contiguity spaces in the sense of Ivanova and Ivanov, respectively and moreover for bunch-determined nearness spaces as Bentley has shown in the past. Further, Do?tch?nov proved that the compactly determined Hausdorff extensions of a given topological space are closely connected with a class of supertopologies which he called b-supertopologies. Now, the new class of supernearness spaces—called paranearness spaces—generalize all of them, and moreover its subclass of clan spaces is in one-to-one correspondence to a certain kind of symmetric strict topological extension. This is leading us to one theorem which generalize all former mentioned.展开更多
The study identified the hotspots and coldspots of poverty as well as the determinants of poverty of each identified group. Data were obtained from National Living Standard Survey and Core Welfare Indicators Questionn...The study identified the hotspots and coldspots of poverty as well as the determinants of poverty of each identified group. Data were obtained from National Living Standard Survey and Core Welfare Indicators Questionnaire Survey conducted by National Bureau of Statistics. Spatial econometrics technique was used to analyze data. The result of the analysis identified the hotspots and coldspots of poverty with average poverty rates of 82.6% and 31.8% respectively. The positive significance of spatial dependence of hotspots (r = 0.34) and coldspots (r = 0.21) indicated that spillover of poverty existed in significant proportion among senatorial districts in the two groups. Percentage of people employed in agriculture, type of soil, annual rainfall, household membership of association and access to credit are found to be important determinants of poverty in hotspots of poverty in Nigeria. Incorporation of poverty spillover when designing poverty alleviation programme, increased productivity of people employed in agriculture and the need to bridge the infrastructural gap between the hotspot and coldspots could play a significant role in reducing poverty incidence significantly in Nigeria.展开更多
We use the Alkire–Foster poverty measure and decomposition method to study multidimensional poverty in the Qinling–Daba contiguous poor area of China's Henan Province.We examine absolute,relative,and multidimens...We use the Alkire–Foster poverty measure and decomposition method to study multidimensional poverty in the Qinling–Daba contiguous poor area of China's Henan Province.We examine absolute,relative,and multidimensional poverty focusing on heads of household and family characteristics as constituents of escaping each.We find that the multidimensional poverty index declines to a low level as values of k increase.Combining first-order random dominance with second-order stochastic dominance quickly determines rankings in the multidimensional poverty index.Increasing non-agricultural income emerges as the most important influence on escaping rural poverty,whereas households with elderly and children are at greatest risk for falling into poverty.展开更多
The studied area consists of 16 counties belonging to 3 provinces or autonomous re-gion, which are Hequ, Baode, Pianguan and Xinxian counties of Shanxi Province; Yulin,Shenmu, Fugu, Hengshan, Jingbian and Dingbian cou...The studied area consists of 16 counties belonging to 3 provinces or autonomous re-gion, which are Hequ, Baode, Pianguan and Xinxian counties of Shanxi Province; Yulin,Shenmu, Fugu, Hengshan, Jingbian and Dingbian counties of Shaanxi Province;Dongsheng, Tuoketuo, Qingshuihe counties and Yijinhuoluo, Dalate, Zhungeer banners展开更多
Summary: To investigate the relationship between proliferative capacity of salivary gland cells in contiguous acini of parotid tumors and recurrent neoplasma, DNA contents of 30 fresh specimens of parotid were studied...Summary: To investigate the relationship between proliferative capacity of salivary gland cells in contiguous acini of parotid tumors and recurrent neoplasma, DNA contents of 30 fresh specimens of parotid were studied by using cytometry in tumors, normal and shallow or deep lobe acini of the masses. The results showed that the DI was 1. 369, S % 16. 95, PI 26. 18 in malignant tumors; DI was 1. 171, S % 12. 41, PI 15. 54 in recurrent pleomorphic adenoma; DI was 1. 141, S % 12. 74, PI 13. 07 in pleornorphic adenoma, DI was 0. 999, S % 5. 10, PI 8. 00 in normal acini. Analysis of variance showed there was a significant difference (P<0. 01 ). The average DNA contents of shallow on deep lobe of contiguous tumors was 1. 08 in DI, 10. 65 in S %, 13. 49 in PI in malignant tumor, 1. 06 in DI, 8. 96 in S % and 9. 85 in PI in pleomorphic adenoma, which were all higher than in normal acini (P>0. 05). It was concluded that the levels of DI and S % of parotid tumor and its contiguous acini are related to degree of malignancy or recurrent condition of the tumors, suggesting contiguous acini of parotid tumors had the strong capacity of proliferation, which might play an important role in recurrent or malignant change of the parotid tumors.展开更多
Recent studies have explored the relationship between aerosol optical depth (AOD) measurements by satellite sensors and concentrations of particulate matter with aerodynamic diameters less than 2.5 μm (PM2.5). Howeve...Recent studies have explored the relationship between aerosol optical depth (AOD) measurements by satellite sensors and concentrations of particulate matter with aerodynamic diameters less than 2.5 μm (PM2.5). However, relatively little is known about spatial and temporal patterns in this relationship across the contiguous United States. In this study, we investigated the relationship between US Environmental Protection Agency estimates of PM2.5 concentrations and Moderate Resolution Imaging Spectroradiometer (MODIS) AOD measurements provided by two NASA satellites (Terra and Aqua) across the contiguous United States during 2005. We found that the combined use of both satellite sensors provided more AOD coverage than the use of either satellite sensor alone, that the correlation between AOD measurements and PM2.5 concentrations varied substantially by geographic location, and that this correlation was stronger in the summer and fall than that in the winter and spring.展开更多
Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and...Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and naturaldisasters, of which water pollution and drought-flood disasters are most observable. Considering the special location andenvironmental status of the contiguous region, advices are proposed in the paper: perfecting trans-regional managementssystem of water environment incorporating basin management agencies in local government activities; strengthening cooperation of two agencies: water conservancy agency and environment protection agency; enhancing integrated control ofwater pollution and flood-drought disasters; taking the interests of the whole river into acount and paying attention to bothstorage and drainage; broadening sources of water supply and inceasing water delivery; controlling pollutant discharge,developing water saving production system.展开更多
Microarray contains a large matrix of information and has been widely used by biologists and bio data scientist for monitoring combinations of genes in different organisms.The coherent patterns in all continuous colum...Microarray contains a large matrix of information and has been widely used by biologists and bio data scientist for monitoring combinations of genes in different organisms.The coherent patterns in all continuous columns are mined in gene microarray data matrices.It is investigated,in this study,the coherent patterns in all continuous columns in gene microarray data matrix by developing the time series similarity measure for the coherent patterns in all continuous columns,as well as the evaluation function for verifying the proposed algorithm and the corresponding biclusters.The continuous time changes are taken into account in the coherent patterns in all continuous columns,and co-expression patterns in time series are searched.In order to use all the common information between sequences,a similarity measure for the coherent patterns in continuous columns is defined in this paper.To validate the efficiency of the similarity measure to mine biological information at continuous time points,an evaluation function is defined to measure biclusters,and an effective algorithm is proposed to mine the biclusters.Simulation experiments are conducted to verify the biological significance of the biclusters,which include synthetic datasets and real gene microarray datasets.The performance of the algorithm is analyzed,and the results show that the algorithm is highly efficient.展开更多
Affected by the mountainous location and ecological vulnerability, the incidence of poverty in contiguous destitute mountainous areas is higher than that in other regions of China. Regional selfdevelopment capacity is...Affected by the mountainous location and ecological vulnerability, the incidence of poverty in contiguous destitute mountainous areas is higher than that in other regions of China. Regional selfdevelopment capacity is an internal driving force for poverty reduction in contiguous destitute mountainous areas. This study selects 17 indicators from the four dimensions: industrial capacity, market capacity, spatial capacity and soft power to measure the overall self-development capacity of 658 counties in 14 different mountain areas in China. The results show that self-development capacity is at a low level and the development of the different regions is unbalanced. The self-development capacity is low in the southwest and high in the east and "low in the middle, high around" in each study region. It has achieved a certain degree of improvement in 2011, 2013 and 2015. From the perspective of the four dimensions, industrial capacity is the constraint on the promotion of self-development capacity. Based on this, we should develop green industries in line with local realities and achieve industrial poverty eradication, but the expansion of space capacity should take into account the resources and environmental carrying capacity in these areas and should not be blindly expanded. Local leaders should be made to improve the local education level and public service level, improve social infrastructure, develop reserve strength for the future, and enhance future development potential.展开更多
A simple immune-based multi-objective optimizer(IBMO) is proposed, and a rigorous running time analysis of IBMO on three proposed bi-objective pseudo-Boolean functions(Bi-Trap, Bi-Plateau and Bi-Jump) is presented. Th...A simple immune-based multi-objective optimizer(IBMO) is proposed, and a rigorous running time analysis of IBMO on three proposed bi-objective pseudo-Boolean functions(Bi-Trap, Bi-Plateau and Bi-Jump) is presented. The running time of a global simple evolutionary multi-objective optimizer(GSEMO) using standard bit mutation operator with IBMO using somatic contiguous hypermutation(CHM) operator is compared with these three functions. The results show that the immune-based hypermutation can significantly beat standard bit mutation on some well-known multi-objective pseudo-Boolean functions. The proofs allow us to understand the relationship between the characteristics of the problems and the features of the algorithms more deeply. These analysis results also give us a good inspiration to analyze and design a bio-inspired search heuristics.展开更多
Multiple contiguous quaternary carbon stereocenters(CQS) are highly challenging, yet important structural motifs in organic synthesis. Here, we describe a visible light induced catalytic [2 + 2] cycloaddition approach...Multiple contiguous quaternary carbon stereocenters(CQS) are highly challenging, yet important structural motifs in organic synthesis. Here, we describe a visible light induced catalytic [2 + 2] cycloaddition approach that constructed up to four CQS in a pentacyclic fused ring system diastereoselectively, from the readily accessible dienamides with pendent heteroaryls. Variously substituted dienamides have been cyclized with heteroaryls to provide a range of novel CQS-containing scaffolds(26 examples, up to 96%yield and >20:1 dr ratio). Mechanistic studies revealed that it may proceed through an uncommon β-C radical initiated 7-endo cyclization from the biradical intermediate.展开更多
The short artide higuights that both location and economic deveopmat of the area is of spedal siwificance in position and funedon.Suggesons covering five aspects are thus raised on econondc deveopmat of the area.
Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2...Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2 seam. The No.9 and No.10-2 seams are contiguous seams. The No.9 seam has been mined out and the No.10-2 seam will be mined under the gob of the No.9 seam. The roof strata of the No.10-2 seam may have been weakened and fractured due to the shear failure caused by the No.9 seam mining activities. The steel beam sets spaced at 0.8 m have been used to support the entry of the No.10-2 seam. In order to speed up the advance rate and cut entry development cost, a test area, using roof bolt in conjunction with truss-system, was successfully conducted. This paper presents the support system design, application of designed system, and the test results. Test results provide a cheaper, quicker, and safer way to support entry for the No.10-2 seam.展开更多
基金supported by the National Natural Science Foundation of China(Nos.81725021,81903461)the National Key R&D Program of China(No.2022YFA1503200)the Natural Science Foundation of Hubei Province(No.ZRMS2023000340)。
文摘Asperfilasin A(1),featuring a unique 5/5 cyclopenta[c]pyrrol-one bicyclic core,represents a newly discovered skeletal cytochalasan isolated from Aspergillus flavipes.The enantioselective total synthesis was efficiently accomplished from the key intermediate(S)-6 with three contiguous stereocenters in 5 steps and the synthetic 1 induced G2/M-phase cell cycle arrest of HT29 cells and apoptosis of HL60 and NB4 cells by activation of caspase-3 and degradation of PARP.(S)-6,bearing three contiguous chiral centers,was efficiently constructed by a novel Nazarov cyclization reaction containing basic nitrogen,which was less developed,primarily due to the incompatibility of basic nitrogen under acidic reaction conditions.This reaction allows a wide range of pentadienone substrates containing basic nitrogen to undergo Nazarov cyclization in a single regioselective and diastereoselective manner and is capable of generating three stereocenters simultaneously.Furthermore,the mechanism of the Nazarov cyclization and the origin of the regio-and diastereoselectivity were elucidated by DFT calculations and deuteration experiments,providing valuable insights into the reaction and serving as a guide for future applications involving substrates containing basic nitrogen.
文摘Norvin Richards’new book Contiguity Theory counts as an important contribution to the study of syntax-phonology interaction.In this book,Richards departs from the standard Minimalist approach which attends to syntactic differences of movement among languages by just positing the diacritic features in some languages,but not in others.He instead rationalizes a set of fundamental principles like Affix Support and Generalized Contiguity,grounded in independent and observable properties of languages.While these principles must be universally satisfied,languages tend to use different mechanisms to realize this goal under the constraint of their own phonological and morphological properties.The different ways employed may thus yield cross-linguistic variations concerning the presence or absence of syntactic movements.Richards’book makes a serious attempt to explore the syntactic variations among languages by taking an interface-oriented approach,with far-reaching implications for understanding how modules interact with each other within the current theory of grammar and accounting for the syntactic variations among various languages.
文摘The 3D reconstruction pipeline uses the Bundle Adjustment algorithm to refine the camera and point parameters. The Bundle Adjustment algorithm is a compute-intensive algorithm, and many researchers have improved its performance by implementing the algorithm on GPUs. In the previous research work, “Improving Accuracy and Computational Burden of Bundle Adjustment Algorithm using GPUs,” the authors demonstrated first the Bundle Adjustment algorithmic performance improvement by reducing the mean square error using an additional radial distorting parameter and explicitly computed analytical derivatives and reducing the computational burden of the Bundle Adjustment algorithm using GPUs. The naïve implementation of the CUDA code, a speedup of 10× for the largest dataset of 13,678 cameras, 4,455,747 points, and 28,975,571 projections was achieved. In this paper, we present the optimization of the Bundle Adjustment algorithm CUDA code on GPUs to achieve higher speedup. We propose a new data memory layout for the parameters in the Bundle Adjustment algorithm, resulting in contiguous memory access. We demonstrate that it improves the memory throughput on the GPUs, thereby improving the overall performance. We also demonstrate an increase in the computational throughput of the algorithm by optimizing the CUDA kernels to utilize the GPU resources effectively. A comparative performance study of explicitly computing an algorithm parameter versus using the Jacobians instead is presented. In the previous work, the Bundle Adjustment algorithm failed to converge for certain datasets due to several block matrices of the cameras in the augmented normal equation, resulting in rank-deficient matrices. In this work, we identify the cameras that cause rank-deficient matrices and preprocess the datasets to ensure the convergence of the BA algorithm. Our optimized CUDA implementation achieves convergence of the Bundle Adjustment algorithm in around 22 seconds for the largest dataset compared to 654 seconds for the sequential implementation, resulting in a speedup of 30×. Our optimized CUDA implementation presented in this paper has achieved a 3× speedup for the largest dataset compared to the previous naïve CUDA implementation.
基金This work was supported by the National Natural Science Foundation of China （No.50074017/EO408)
文摘Effect of Mo and Mo2 C on the microstructure and properties of Ti（C,N）-based cermets was investigated in this article. The results have indicated that the weight percentage of Mo from 5 to 10 can reduce Ti（C,N） grain diameter and thickness of the rim, and Ti（C,N） grain can be wetted by Ni-Cu-Mo liquid so as to get small contiguity of Ti（C,N） grain. In that way, the transverse rupture strength of Ti（C,N）-based cermets has reached 1800-1900 MPa; the fracture toughness has been due to 16-18 MPa.m1/2. But 15 wt pct Mo was not more effective on Ti（C,N）-based cermets, because the thickness of the rim becomes larger. In the circumstance of Mo2 C, 5 wt pct Mo2 C was good for microstructure and properties of Ti（C,N）-based cermets, but 11 wt pct Mo2C has resulted in larger contiguity of Ti（C,N） grain and big Ti（C,N） grain diameter so as to reduce transverse rupture strength and fracture toughness. So that, the effect of Mo on Ti（C,N）-based cermets is better than Mo2C.
文摘The aim of this research was to examine the effect of microstructural parameters on the tensile properties of different compositions of tungsten heavy alloys. The microstructural parameters （grain size, connectivity, contiguity, and solid volume fraction） were measured and were found to have a significant effect on the tensile properties of tungsten-based heavy alloys. The microstructural parameters of W-Ni-Fe alloys are sufficiently different to present a range of mechanical properties. It is concluded that the mechanical properties of tungsten heavy alloys largely depend on the microstructural parameters and their ductility is particularly harmed when grains are contiguous.
文摘Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased estimator of variance does not exist for this design.Oftentimes,a quasi-default estimator applicable to simple random sampling(SRS)is used,even if it carries with it the likely risk of overestimating the variance by a practically important margin.To better exploit the precision of systematic sampling we assess the performance of five estimators of variance,including the quasi default.In this study,simulated systematic sampling was applied to artificial populations with contrasting covariance structures and with or without linear trends.We compared the results obtained with the SRS,Matern’s,successive difference replication,Ripley’s,and D’Orazio’s variance estimators.Results:The variances obtained with the four alternatives to the SRS estimator of variance were strongly correlated,and in all study settings consistently closer to the target design variance than the estimator for SRS.The latter always produced the greatest overestimation.In populations with a near zero spatial autocorrelation,all estimators,performed equally,and delivered estimates close to the actual design variance.Conclusion:Without a linear trend,the SDR and DOR estimators were best with variance estimates more narrowly distributed around the benchmark;yet in terms of the least average absolute deviation,Matern’s estimator held a narrow lead.With a strong or moderate linear trend,Matern’s estimator is choice.In large populations,and a low sampling intensity,the performance of the investigated estimators becomes more similar.
文摘In the paper in order to ascertain the condition of the right-bank of the dam at the Vilyui hydroelectric power plant measurements are applied to obtain experimentaldate such as drilling borehole, hydrolocationand so forth. By finding out the distribution of the temperature field some corresponding measures are taken to improve the stability of the dam during the change of the ground temperature. And finally some conclusions are draw to the study.
文摘In the realm of Bounded Topology we now consider supernearness spaces as a common generalization of various kinds of topological structures. Among them the so-called Lodato spaces are of significant interest. In one direction they are standing in one-to-one correspondence to some kind of topological extensions. This last statement also holds for contiguity spaces in the sense of Ivanova and Ivanov, respectively and moreover for bunch-determined nearness spaces as Bentley has shown in the past. Further, Do?tch?nov proved that the compactly determined Hausdorff extensions of a given topological space are closely connected with a class of supertopologies which he called b-supertopologies. Now, the new class of supernearness spaces—called paranearness spaces—generalize all of them, and moreover its subclass of clan spaces is in one-to-one correspondence to a certain kind of symmetric strict topological extension. This is leading us to one theorem which generalize all former mentioned.
文摘The study identified the hotspots and coldspots of poverty as well as the determinants of poverty of each identified group. Data were obtained from National Living Standard Survey and Core Welfare Indicators Questionnaire Survey conducted by National Bureau of Statistics. Spatial econometrics technique was used to analyze data. The result of the analysis identified the hotspots and coldspots of poverty with average poverty rates of 82.6% and 31.8% respectively. The positive significance of spatial dependence of hotspots (r = 0.34) and coldspots (r = 0.21) indicated that spillover of poverty existed in significant proportion among senatorial districts in the two groups. Percentage of people employed in agriculture, type of soil, annual rainfall, household membership of association and access to credit are found to be important determinants of poverty in hotspots of poverty in Nigeria. Incorporation of poverty spillover when designing poverty alleviation programme, increased productivity of people employed in agriculture and the need to bridge the infrastructural gap between the hotspot and coldspots could play a significant role in reducing poverty incidence significantly in Nigeria.
基金supported by the National Natural Science Foundation of China[Grant number.41601112].
文摘We use the Alkire–Foster poverty measure and decomposition method to study multidimensional poverty in the Qinling–Daba contiguous poor area of China's Henan Province.We examine absolute,relative,and multidimensional poverty focusing on heads of household and family characteristics as constituents of escaping each.We find that the multidimensional poverty index declines to a low level as values of k increase.Combining first-order random dominance with second-order stochastic dominance quickly determines rankings in the multidimensional poverty index.Increasing non-agricultural income emerges as the most important influence on escaping rural poverty,whereas households with elderly and children are at greatest risk for falling into poverty.
文摘The studied area consists of 16 counties belonging to 3 provinces or autonomous re-gion, which are Hequ, Baode, Pianguan and Xinxian counties of Shanxi Province; Yulin,Shenmu, Fugu, Hengshan, Jingbian and Dingbian counties of Shaanxi Province;Dongsheng, Tuoketuo, Qingshuihe counties and Yijinhuoluo, Dalate, Zhungeer banners
文摘Summary: To investigate the relationship between proliferative capacity of salivary gland cells in contiguous acini of parotid tumors and recurrent neoplasma, DNA contents of 30 fresh specimens of parotid were studied by using cytometry in tumors, normal and shallow or deep lobe acini of the masses. The results showed that the DI was 1. 369, S % 16. 95, PI 26. 18 in malignant tumors; DI was 1. 171, S % 12. 41, PI 15. 54 in recurrent pleomorphic adenoma; DI was 1. 141, S % 12. 74, PI 13. 07 in pleornorphic adenoma, DI was 0. 999, S % 5. 10, PI 8. 00 in normal acini. Analysis of variance showed there was a significant difference (P<0. 01 ). The average DNA contents of shallow on deep lobe of contiguous tumors was 1. 08 in DI, 10. 65 in S %, 13. 49 in PI in malignant tumor, 1. 06 in DI, 8. 96 in S % and 9. 85 in PI in pleomorphic adenoma, which were all higher than in normal acini (P>0. 05). It was concluded that the levels of DI and S % of parotid tumor and its contiguous acini are related to degree of malignancy or recurrent condition of the tumors, suggesting contiguous acini of parotid tumors had the strong capacity of proliferation, which might play an important role in recurrent or malignant change of the parotid tumors.
文摘Recent studies have explored the relationship between aerosol optical depth (AOD) measurements by satellite sensors and concentrations of particulate matter with aerodynamic diameters less than 2.5 μm (PM2.5). However, relatively little is known about spatial and temporal patterns in this relationship across the contiguous United States. In this study, we investigated the relationship between US Environmental Protection Agency estimates of PM2.5 concentrations and Moderate Resolution Imaging Spectroradiometer (MODIS) AOD measurements provided by two NASA satellites (Terra and Aqua) across the contiguous United States during 2005. We found that the combined use of both satellite sensors provided more AOD coverage than the use of either satellite sensor alone, that the correlation between AOD measurements and PM2.5 concentrations varied substantially by geographic location, and that this correlation was stronger in the summer and fall than that in the winter and spring.
文摘Owing to intensive human activities and the floods of the Huaihe River in historic peiod, the contiguous region of Jiangsu, Shandong, Henan and Anhui provinces is suffering from a variety of environmental problems and naturaldisasters, of which water pollution and drought-flood disasters are most observable. Considering the special location andenvironmental status of the contiguous region, advices are proposed in the paper: perfecting trans-regional managementssystem of water environment incorporating basin management agencies in local government activities; strengthening cooperation of two agencies: water conservancy agency and environment protection agency; enhancing integrated control ofwater pollution and flood-drought disasters; taking the interests of the whole river into acount and paying attention to bothstorage and drainage; broadening sources of water supply and inceasing water delivery; controlling pollutant discharge,developing water saving production system.
基金supported by China Scholarship Council,Guangdong Science and Technology Department under Grant no.2016A010101020,2016A010101021,2016A010101022Guangzhou Science and Information Bureau under Grant no 201802010033.
文摘Microarray contains a large matrix of information and has been widely used by biologists and bio data scientist for monitoring combinations of genes in different organisms.The coherent patterns in all continuous columns are mined in gene microarray data matrices.It is investigated,in this study,the coherent patterns in all continuous columns in gene microarray data matrix by developing the time series similarity measure for the coherent patterns in all continuous columns,as well as the evaluation function for verifying the proposed algorithm and the corresponding biclusters.The continuous time changes are taken into account in the coherent patterns in all continuous columns,and co-expression patterns in time series are searched.In order to use all the common information between sequences,a similarity measure for the coherent patterns in continuous columns is defined in this paper.To validate the efficiency of the similarity measure to mine biological information at continuous time points,an evaluation function is defined to measure biclusters,and an effective algorithm is proposed to mine the biclusters.Simulation experiments are conducted to verify the biological significance of the biclusters,which include synthetic datasets and real gene microarray datasets.The performance of the algorithm is analyzed,and the results show that the algorithm is highly efficient.
基金This study was supported by the Natural Science Foundation of China(No.71803106)the Ministry of Education of Humanities and Social Science Project(No.16YJCZH131)Key Projects of Soft Science Foundation of Shanxi Science and Technology Department(No.2019042002-4)。
文摘Affected by the mountainous location and ecological vulnerability, the incidence of poverty in contiguous destitute mountainous areas is higher than that in other regions of China. Regional selfdevelopment capacity is an internal driving force for poverty reduction in contiguous destitute mountainous areas. This study selects 17 indicators from the four dimensions: industrial capacity, market capacity, spatial capacity and soft power to measure the overall self-development capacity of 658 counties in 14 different mountain areas in China. The results show that self-development capacity is at a low level and the development of the different regions is unbalanced. The self-development capacity is low in the southwest and high in the east and "low in the middle, high around" in each study region. It has achieved a certain degree of improvement in 2011, 2013 and 2015. From the perspective of the four dimensions, industrial capacity is the constraint on the promotion of self-development capacity. Based on this, we should develop green industries in line with local realities and achieve industrial poverty eradication, but the expansion of space capacity should take into account the resources and environmental carrying capacity in these areas and should not be blindly expanded. Local leaders should be made to improve the local education level and public service level, improve social infrastructure, develop reserve strength for the future, and enhance future development potential.
基金the National Natural Science Foundation of China(Nos.61703183,61773410,61375053)the Public Welfare Technology Research Plan of Zhejiang Province(No.LGG19F030010)
文摘A simple immune-based multi-objective optimizer(IBMO) is proposed, and a rigorous running time analysis of IBMO on three proposed bi-objective pseudo-Boolean functions(Bi-Trap, Bi-Plateau and Bi-Jump) is presented. The running time of a global simple evolutionary multi-objective optimizer(GSEMO) using standard bit mutation operator with IBMO using somatic contiguous hypermutation(CHM) operator is compared with these three functions. The results show that the immune-based hypermutation can significantly beat standard bit mutation on some well-known multi-objective pseudo-Boolean functions. The proofs allow us to understand the relationship between the characteristics of the problems and the features of the algorithms more deeply. These analysis results also give us a good inspiration to analyze and design a bio-inspired search heuristics.
基金supported by the National Natural Science Foundation of China(Nos.82122063,81991522 and 81973232)Shandong Science Fund for Distinguished Young Scholars(No.ZR2020JQ32)the Fundamental Research Funds for the Central Universities(No.202041003)。
文摘Multiple contiguous quaternary carbon stereocenters(CQS) are highly challenging, yet important structural motifs in organic synthesis. Here, we describe a visible light induced catalytic [2 + 2] cycloaddition approach that constructed up to four CQS in a pentacyclic fused ring system diastereoselectively, from the readily accessible dienamides with pendent heteroaryls. Variously substituted dienamides have been cyclized with heteroaryls to provide a range of novel CQS-containing scaffolds(26 examples, up to 96%yield and >20:1 dr ratio). Mechanistic studies revealed that it may proceed through an uncommon β-C radical initiated 7-endo cyclization from the biradical intermediate.
文摘The short artide higuights that both location and economic deveopmat of the area is of spedal siwificance in position and funedon.Suggesons covering five aspects are thus raised on econondc deveopmat of the area.
文摘Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2 seam. The No.9 and No.10-2 seams are contiguous seams. The No.9 seam has been mined out and the No.10-2 seam will be mined under the gob of the No.9 seam. The roof strata of the No.10-2 seam may have been weakened and fractured due to the shear failure caused by the No.9 seam mining activities. The steel beam sets spaced at 0.8 m have been used to support the entry of the No.10-2 seam. In order to speed up the advance rate and cut entry development cost, a test area, using roof bolt in conjunction with truss-system, was successfully conducted. This paper presents the support system design, application of designed system, and the test results. Test results provide a cheaper, quicker, and safer way to support entry for the No.10-2 seam.
