The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield...The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield tunneling remains inadequate.The analytical solution for calculating the deformation of the ground and existing tunnel induced by overlapped curved shield tunneling is derived by the Mirror theory,Mindlin solution and Euler-Bernoulli-Pasternak model,subsequently validated through both finite element simulation and field monitoring.It is determined that the overcutting plays a crucial role in the ground settlement resulting from curved shield tunneling compared to straight shield tunneling.The longitudinal settlement distribution can be categorized into five areas,with the area near the tunnel surface experiencing the most dramatic settlement changes.The deformation of the existing tunnel varies most significantly with turning radius compared to tunnel clearance and grouting pressure,especially when the turning radius is less than 30 times the tunnel diameter.The tunnel crown exhibits larger displacement than the tunnel bottom,resulting in a distinctive‘vertical egg'shape.Furthermore,an optimized overcutting mode is proposed,involving precise control of the extension speed and angular velocity of the overcutting cutter,which effectively mitigates ground deformation,ensuring the protection of the existing tunnel during the construction.展开更多
A resolution method based on Gaussian-like distribution for overlapped linear sweep polarographic peaks was proposed to simultaneously detect the polymetallic components, such as Zn（Ⅱ） and Co（Ⅱ）, coexisting in t...A resolution method based on Gaussian-like distribution for overlapped linear sweep polarographic peaks was proposed to simultaneously detect the polymetallic components, such as Zn（Ⅱ） and Co（Ⅱ）, coexisting in the leaching solution of zinc hydrometallurgy. A Gaussian-like distribution was constructed as the sub-model of overlapped peaks by analyzing the characteristics of linear sweep polarographic curve. Then, the abscissas of each peak and trough were pinpointed through multi-resolution wavelet decomposition, the curve and its derivative curves were fitted by using nonlinear weighted least squares （NWLS）. Finally, overlapped peaks were resolved into independent sub-peaks based on fitted reconstruction parameters. The experimental results show that the relative error of half-wave potential pinpointed by multi-resolution wavelet decomposition is less than 1% and the accuracy of Ip fitted by NWLS is higher than 96%. The proposed resolution method is effective for overlapped linear sweep polarographic peaks of Zn（Ⅱ） and Co（Ⅱ）.展开更多
Medical image analysis based on deep learning has become an important technical requirement in the field of smart healthcare.In view of the difficulties in collaborative modeling of local details and global features i...Medical image analysis based on deep learning has become an important technical requirement in the field of smart healthcare.In view of the difficulties in collaborative modeling of local details and global features in multimodal image analysis of ophthalmology,as well as the existence of information redundancy in cross-modal data fusion,this paper proposes amultimodal fusion framework based on cross-modal collaboration and weighted attention mechanism.In terms of feature extraction,the framework collaboratively extracts local fine-grained features and global structural dependencies through a parallel dual-branch architecture,overcoming the limitations of traditional single-modality models in capturing either local or global information;in terms of fusion strategy,the framework innovatively designs a cross-modal dynamic fusion strategy,combining overlappingmulti-head self-attention modules with a bidirectional feature alignment mechanism,addressing the bottlenecks of low feature interaction efficiency and excessive attention fusion computations in traditional parallel fusion,and further introduces cross-domain local integration technology,which enhances the representation ability of the lesion area through pixel-level feature recalibration and optimizes the diagnostic robustness of complex cases.Experiments show that the framework exhibits excellent feature expression and generalization performance in cross-domain scenarios of ophthalmic medical images and natural images,providing a high-precision,low-redundancy fusion paradigm for multimodal medical image analysis,and promoting the upgrade of intelligent diagnosis and treatment fromsingle-modal static analysis to dynamic decision-making.展开更多
Similarity measure design on non-overlapped data was carried out and compared with the case of overlapped data.Unconsistant feature of similarity on overlapped data to non-overlapped data was provided by example.By th...Similarity measure design on non-overlapped data was carried out and compared with the case of overlapped data.Unconsistant feature of similarity on overlapped data to non-overlapped data was provided by example.By the artificial data illustration,it was proved that the conventional similarity measure was not proper to calculate the similarity measure of the non-overlapped case.To overcome the unbalance problem,similarity measure on non-overlapped data was obtained by considering neighbor information.Hence,different approaches to design similarity measure were proposed and proved by consideration of neighbor information.With the example of artificial data,similarity measure calculation was carried out.Similarity measure extension to intuitionistic fuzzy sets(IFSs)containing uncertainty named hesitance was also followed.展开更多
AIM To introduce an innovative intracorporeal anastomosis technique named overlapped delta-shaped anastomosis(ODA)for colon cancer cases undergoing totally laparoscopic colectomy(TLC)and to assess its feasibility and ...AIM To introduce an innovative intracorporeal anastomosis technique named overlapped delta-shaped anastomosis(ODA)for colon cancer cases undergoing totally laparoscopic colectomy(TLC)and to assess its feasibility and safety. METHODS From January 2016 to March 2017,a total of 20consecutive patients with colon cancer accepted TLC and the ODA technique at our medical center.Patient demographics,operative outcomes,perioperative complications,and pathological results were collected and analyzed. RESULTS We successfully completed TLC and the ODA procedure in all 20 cases,including 6(30%)males and 14(70%)females.In total,11(55%),2(10%),and 7(35%)cases accepted right hemicolectomy,transverse hemicolectomy,and left hemicolectomy,respectively.None of the surgeries were converted to an open operation.Mean operative time was 178.5 min,and mean estimated blood loss was 58.5 m L.Mean time to first flatus was 2.5 d,and mean postoperative hospitalization duration was 6.8 d.No severe complications occurred,such as anastomotic leakage,snastomotic stenosis,anastomotic bleeding,and wound infection,except for one case who suffered from an abdominal infection and another case who suffered from gastric paralysis syndrome.Tumor recurrence was not observed in any patient during the follow-up period. CONCLUSION The ODA technique for colon cancer cases undergoing TLC appears to be safe and feasible,although our current results need to be verified in further studies.展开更多
The unprecedented rate of metro construction has led to a highly complex network of metro lines.Tunnels are being overlapped to an ever-increasing degree.This paper investigates the deformation response of double-trac...The unprecedented rate of metro construction has led to a highly complex network of metro lines.Tunnels are being overlapped to an ever-increasing degree.This paper investigates the deformation response of double-track overlapped tunnels in Tianjin,China using finite element analysis(FEA)and field monitoring,considering the attributes of different tunneling forms.With respect to the upper tunneling,the results of the FEA and field monitoring showed that the maximum vertical displacements of the ground surface during the tail passage were 2.06 mm,2.25 mm and 2.39 mm obtained by the FEA,field monitoring and Peck calculation,respectively;the heaves on the vertical displacement curve were observed at 8 m(1.25D,where D is the diameter of the tunnel)away from the center of the tunnel and the curve at both sides was asymmetrical.Furthermore,the crown and bottom produce approximately0.38 mm and 1.26 mm of contraction,respectively.The results of the FEA of the upper and lower sections demonstrated that the tunneling form has an obvious influence on the deformation response of the double-track overlapped tunnel.Compared with the upper tunneling,the lower tunneling exerted significantly less influence on the deformation response,which manifested as a smaller displacement of the strata and deformation of the existing tunnel.The results of this study on overlapped tunnels can provide a reference for similar projects in the future.展开更多
Capacity reduction is a major problem faced by wireless mesh networks. An efficient way to alleviate this problem is proper channel assignment. Current end-toend channel assignment schemes usually focus on the case wh...Capacity reduction is a major problem faced by wireless mesh networks. An efficient way to alleviate this problem is proper channel assignment. Current end-toend channel assignment schemes usually focus on the case where channels in distinct frequency bands are assigned to mesh access and backbone, but actually backbone network and access network can use the same IEEE 802.11 technology. Besides, these channel assignment schemes only utilize orthogonal channels to perform channel assignment, and the resulting network interference dramatically degrades network performance. Moreover, Internet-oriented traffic is considered only, and peerto-peer traffic is omitted, or vice versa. The traffic type does not match the practical network. In this paper, we explore how to exploit partially overlapped channels to perform endto-end channel assignment in order to achieve effective end-to-end flow transmissions. The proposed flow-based end-to-end channel assignment schemes can conquer the limitations aforementioned. Simulations reveal that loadaware channel assignment can be applied to networks with stable traffic load, and it can achieve near-optimal performance; Traffic-irrelevant channel assignment is suitable for networks with frequent change of traffic load,and it can achieve good balance between performance and overhead. Also, partially overlapped channels' capability of improving network performance is situation-dependent, they should be used carefully.展开更多
A new digital communication technology based on the Phase-Offset Overlapped Waves (POOW) has been introduced in this letter. The waves can be considered as a special multicarrier different from traditional ones. The s...A new digital communication technology based on the Phase-Offset Overlapped Waves (POOW) has been introduced in this letter. The waves can be considered as a special multicarrier different from traditional ones. The sub-waves in a coded word's period of the POOW are sine waves and have the same frequencies, but different starting phases. The most important characteristic is that these sub-waves are the piecewise functions and not orthogonal in a code word period. The decoding can be implemented by solving a linear equation group. This code has very high efficiency and thus the data transmission rate is increased greatly.展开更多
The movement mode of snakes is crawling,and the living environment of snakes with numerous branches and stones will cause plenty of wear for the snake scales.There are plenty of surface structures and morphology on sn...The movement mode of snakes is crawling,and the living environment of snakes with numerous branches and stones will cause plenty of wear for the snake scales.There are plenty of surface structures and morphology on snake scales to avoid severe wear.Among them,the research towards the keeled structure on snake scales is missing.Therefore,in this research,the wear resistance improvement of the keeled structure on the snake scales and the overlapped distribution of snake scales are investigated.The keeled and smooth snake scales were 3D printed and they were distributed on the substrate in the overlapped or paralleled ways.Besides these four samples with keeled/smooth scales and overlapped/paralleled distributed,there is also a reference sample with the same thickness.Based on the tribology test,the number of grooves of samples with the keeled structures is higher than that of samples with smooth surfaces,which indicates that the keeled structure dramatically enhances the wear resistance of snake scales,especially during the wear in the vertical direction.The experiment on surface morphology greatly compromised the result of the tribology test.In addition,the bottom portion of the keeled snake scales can be protected by the keeled structure.Besides,the overlapped distribution can protect the central region of snake scales and provide double-layer protection of the snake body.Overall,the keeled structure and the overlapped distribution play a significant part in the improvement of wear resistance of the snake skin.These findings can enhance the knowledge of the reptiles-mimic surface structure and facilitate the application of military uniforms under high-wear conditions.展开更多
This paper investigates a wireless system with multi-Unmanned Aerial Vehicles(UAVs)for improving the overall throughput.In contrast to previous studies that optimize the locations of UAVs and channel assignment separa...This paper investigates a wireless system with multi-Unmanned Aerial Vehicles(UAVs)for improving the overall throughput.In contrast to previous studies that optimize the locations of UAVs and channel assignment separately,this paper considers the two issues jointly by exploiting Partially Overlapped Channels(POCs).The optimization problem of maximizing network throughput is formulated as a non-convex and non-linear problem.In order to find a practical solution,the problem is decomposed into two subproblems,which are iteratively optimized.First,the optimal locations of UAVs are determined under a fixed channel assignment scheme by solving the mixed-integer second-order cone problem.Second,an efficient POC allocation scheme is determined via the proposed channel assignment algorithm.Simulation results show that the proposed approach not only significantly improves system throughput and service reliability compared with the cases in which only orthogonal channels and stationary UAVs are considered,but also achieves similar performance using the exhaustive search algorithm with lower time complexity.展开更多
This paper presents a novel architecture of combining the linear array of antenna elements, where each antenna element has digitally selectable true time-delays as weights. Use of time-delays for beam-formation inhere...This paper presents a novel architecture of combining the linear array of antenna elements, where each antenna element has digitally selectable true time-delays as weights. Use of time-delays for beam-formation inherently makes the phased array network a wideband system. In particular, this technique envisage a new method of sharing antenna elements, by fixed overlapped sub-array architecture, which is able to maintain permissible element spacing to avoid grating lobe in antenna pattern. Moreover, this scheme additionally offers an easier null steering capability to the subarray architecture. This method essentially eliminates the need for intensive computation of complex weight vectors attached to each antenna element.展开更多
This paper presents an innovative eccentric jacket substructure for offshore wind turbines to better withstand intense environmental forces and to replace conventional X-braced jackets in seismically active areas. The...This paper presents an innovative eccentric jacket substructure for offshore wind turbines to better withstand intense environmental forces and to replace conventional X-braced jackets in seismically active areas. The proposed eccentric jacket comprises of completely overlapped joint at every joint connection. The joint consists of a chord and two braces in a single plane. The two braces are fully overlapped with a short segment of the diagonal brace welded directly onto the chord. The characteristic feature of this joint configuration is that the short segment member can be designed to absorb and dissipate energy under cyclic load excitation. The experimental and numerical study revealed that the completely overlapped joint performed better in terms of strength resistance, stiffness, ductility, and energy absorption capacity than the conventional gap joints commonly found in typical X-braced jacket framings. The eccentric jacket could also be designed to becoming less stiff, with an inelastic yielding and local buckling of short segment member, so as to better resist the cyclic load generated from intense environmental forces and earthquake. From the design economics, the eccentric jacket provided a more straightforward fabrication with reduced number of welded joints and shorter thicker wall cans than the conventional X-braced jacket. It can therefore be concluded based on the results presented in the study that by designing the short segment member in accordance with strength and ductility requirement,the eccentric jacket substructure supporting the wind turbine could be made to remain stable under gravity loads and to sustain a significantly large amount of motion in the event of rare and intense earthquake or environmental forces, without collapsing.展开更多
A nested genetic algorithm, including genetic parameter level and genetic implemented level for peak parameters, was proposed and applied for resolving overlapped spectral bands. By the genetic parameter level, parame...A nested genetic algorithm, including genetic parameter level and genetic implemented level for peak parameters, was proposed and applied for resolving overlapped spectral bands. By the genetic parameter level, parameters of generic algorithm were optimized; moreover, the number of overlapped peaks was determined simultaneously Then parameters of individual peaks were computed with the genetic implemented level.展开更多
A new method called spline convolution (SC) for resolving overlapped peaks was proposed in this paper. The differential pulse voltammetric overlapped peaks of mixtures of Pb(II) and Tl(I) were investigated by this me...A new method called spline convolution (SC) for resolving overlapped peaks was proposed in this paper. The differential pulse voltammetric overlapped peaks of mixtures of Pb(II) and Tl(I) were investigated by this method, and satisfactory results were obtained. The results show excellent correlation between peak areas of the processed signals and the concentrations.展开更多
With the development of China's social economy,transfer of rural labors,and rise of labor costs,the rice production technologies are changing from manual operation to mechanical operation.The core of mechanical ri...With the development of China's social economy,transfer of rural labors,and rise of labor costs,the rice production technologies are changing from manual operation to mechanical operation.The core of mechanical rice production is mechanical planting,while the key to mechanical planting is the seedling raising.On the basis of analyzing and studying the problems and experience of traditional mechanical transplanting of rice,a new overlapped tray seedling raising model was introduced.Main features of this model: substrate seedling raising and overlapped seedling tray.The seedling trays for seeding line are overlapped,and the overlapped trays are moved into the seedling room with controlled temperature and humidity.The temperature of the seedling room is controlled at 30-32℃,and the humidity of the seedling room is controlled at above 90%.After about 48 h,when the seedling height reaches 0.5 cm,move the seedling trays to the nursery.This model consists of one seeding center( seedling raising center) and N nurseries,to realize 1 + N seedling raising for mechanical transplanting of rice.One seeding center can provide seedlings for several hundred to several thousand hectares of mechanical transplanting of rice,and provide a new model for social services.This model could improve the quality of seedlings,increase the seedling survival rate by about 20%,reduce the seedling raising costs by 15%-20%,reduce the seedling raising risks,and greatly increase the utilization rate of the site and equipment of seedling raising center.展开更多
BACKGROUND Overlapped esophagojejunostomy(OEJ) is a secure purely laparoscopic reconstruction after laparoscopic total gastrectomy(LTG). However, long-term surgical results have not been documented well.AIM In this pa...BACKGROUND Overlapped esophagojejunostomy(OEJ) is a secure purely laparoscopic reconstruction after laparoscopic total gastrectomy(LTG). However, long-term surgical results have not been documented well.AIM In this paper, we report unusual patients who manifested jejunal limb stricture near the esophageal hiatus without anastomotic stenosis during long-term observation after surgery.METHODS From April 2009 until May 2020, we retrospectively reviewed 211 patients underwent LTG following by OEJ for gastric carcinoma and took a standard surveillance program. We aimed to characterize a novel complicated disorder observed in these patients to assist treatment and prevention.RESULTS Five patients(2.4%) had unusual jejunal limb stricture after LTG and OEJ,occurring at a mean of 10 mo after initial radical LTG. All five patients had disturbed oral intake and marked weight loss, and two had aspiration pneumonia.Various diagnostic modalities and intraoperative findings in each patient revealed an intact anastomosis, bent or tortuous jejunal limb resulting from loose fibrous adhesions on the left crus at the esophageal hiatus and no cancer recurrence. All five patients were successfully treated by reoperation for adhesiolysis, division of the left crus and rearrangement of the jejunal limb.CONCLUSION Disturbed passage through the jejunal limb near the hiatus can occur after some types of OEJ following LTG. We speculate that it may result from a short remnant esophagus, excessive mobilization of the jejunal limb that permits bending or tortuosity and adhesions on the left crus at the hiatus. Prevention for this complication is possible during the original LTG procedure.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.52078334)the National Key Research and Development Program of China(Grant No.2017YFC0805402)the Tianjin Research Innovation Project for Postgraduate Students(Grant No.2021YJSB141).
文摘The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield tunneling remains inadequate.The analytical solution for calculating the deformation of the ground and existing tunnel induced by overlapped curved shield tunneling is derived by the Mirror theory,Mindlin solution and Euler-Bernoulli-Pasternak model,subsequently validated through both finite element simulation and field monitoring.It is determined that the overcutting plays a crucial role in the ground settlement resulting from curved shield tunneling compared to straight shield tunneling.The longitudinal settlement distribution can be categorized into five areas,with the area near the tunnel surface experiencing the most dramatic settlement changes.The deformation of the existing tunnel varies most significantly with turning radius compared to tunnel clearance and grouting pressure,especially when the turning radius is less than 30 times the tunnel diameter.The tunnel crown exhibits larger displacement than the tunnel bottom,resulting in a distinctive‘vertical egg'shape.Furthermore,an optimized overcutting mode is proposed,involving precise control of the extension speed and angular velocity of the overcutting cutter,which effectively mitigates ground deformation,ensuring the protection of the existing tunnel during the construction.
基金Project(2012BAF03B05)supported by the National Key Technology R&D Program of ChinaProject(61025015)supported by the National Natural Science Foundation for Distinguished Young Scholars of China+1 种基金Project(61273185)supported by the National Natural Science Foundation of ChinaProject(2012CK4018)supported by the Science and Technology Project of Hunan Province,China
文摘A resolution method based on Gaussian-like distribution for overlapped linear sweep polarographic peaks was proposed to simultaneously detect the polymetallic components, such as Zn（Ⅱ） and Co（Ⅱ）, coexisting in the leaching solution of zinc hydrometallurgy. A Gaussian-like distribution was constructed as the sub-model of overlapped peaks by analyzing the characteristics of linear sweep polarographic curve. Then, the abscissas of each peak and trough were pinpointed through multi-resolution wavelet decomposition, the curve and its derivative curves were fitted by using nonlinear weighted least squares （NWLS）. Finally, overlapped peaks were resolved into independent sub-peaks based on fitted reconstruction parameters. The experimental results show that the relative error of half-wave potential pinpointed by multi-resolution wavelet decomposition is less than 1% and the accuracy of Ip fitted by NWLS is higher than 96%. The proposed resolution method is effective for overlapped linear sweep polarographic peaks of Zn（Ⅱ） and Co（Ⅱ）.
基金funded by the Ongoing Research Funding Program(ORF-2025-102),King Saud University,Riyadh,Saudi Arabiaby the Science and Technology Research Programof Chongqing Municipal Education Commission(Grant No.KJQN202400813)by the Graduate Research Innovation Project(Grant Nos.yjscxx2025-269-193 and CYS25618).
文摘Medical image analysis based on deep learning has become an important technical requirement in the field of smart healthcare.In view of the difficulties in collaborative modeling of local details and global features in multimodal image analysis of ophthalmology,as well as the existence of information redundancy in cross-modal data fusion,this paper proposes amultimodal fusion framework based on cross-modal collaboration and weighted attention mechanism.In terms of feature extraction,the framework collaboratively extracts local fine-grained features and global structural dependencies through a parallel dual-branch architecture,overcoming the limitations of traditional single-modality models in capturing either local or global information;in terms of fusion strategy,the framework innovatively designs a cross-modal dynamic fusion strategy,combining overlappingmulti-head self-attention modules with a bidirectional feature alignment mechanism,addressing the bottlenecks of low feature interaction efficiency and excessive attention fusion computations in traditional parallel fusion,and further introduces cross-domain local integration technology,which enhances the representation ability of the lesion area through pixel-level feature recalibration and optimizes the diagnostic robustness of complex cases.Experiments show that the framework exhibits excellent feature expression and generalization performance in cross-domain scenarios of ophthalmic medical images and natural images,providing a high-precision,low-redundancy fusion paradigm for multimodal medical image analysis,and promoting the upgrade of intelligent diagnosis and treatment fromsingle-modal static analysis to dynamic decision-making.
文摘Similarity measure design on non-overlapped data was carried out and compared with the case of overlapped data.Unconsistant feature of similarity on overlapped data to non-overlapped data was provided by example.By the artificial data illustration,it was proved that the conventional similarity measure was not proper to calculate the similarity measure of the non-overlapped case.To overcome the unbalance problem,similarity measure on non-overlapped data was obtained by considering neighbor information.Hence,different approaches to design similarity measure were proposed and proved by consideration of neighbor information.With the example of artificial data,similarity measure calculation was carried out.Similarity measure extension to intuitionistic fuzzy sets(IFSs)containing uncertainty named hesitance was also followed.
基金Supported by the Central Level and Public Welfare Basal Research Fund of Chinese Academy of Medical Sciences,No.2016ZX310020
文摘AIM To introduce an innovative intracorporeal anastomosis technique named overlapped delta-shaped anastomosis(ODA)for colon cancer cases undergoing totally laparoscopic colectomy(TLC)and to assess its feasibility and safety. METHODS From January 2016 to March 2017,a total of 20consecutive patients with colon cancer accepted TLC and the ODA technique at our medical center.Patient demographics,operative outcomes,perioperative complications,and pathological results were collected and analyzed. RESULTS We successfully completed TLC and the ODA procedure in all 20 cases,including 6(30%)males and 14(70%)females.In total,11(55%),2(10%),and 7(35%)cases accepted right hemicolectomy,transverse hemicolectomy,and left hemicolectomy,respectively.None of the surgeries were converted to an open operation.Mean operative time was 178.5 min,and mean estimated blood loss was 58.5 m L.Mean time to first flatus was 2.5 d,and mean postoperative hospitalization duration was 6.8 d.No severe complications occurred,such as anastomotic leakage,snastomotic stenosis,anastomotic bleeding,and wound infection,except for one case who suffered from an abdominal infection and another case who suffered from gastric paralysis syndrome.Tumor recurrence was not observed in any patient during the follow-up period. CONCLUSION The ODA technique for colon cancer cases undergoing TLC appears to be safe and feasible,although our current results need to be verified in further studies.
基金financially supported by the Open Project of the State Key Laboratory of Disaster Reduction in Civil Engineering(Grant No.SLDRCE17-01)the National Key Research and Development Program of China(Grant No.2017YFC0805402)the National Natural Science Foundation of China(Grant No.51808387)。
文摘The unprecedented rate of metro construction has led to a highly complex network of metro lines.Tunnels are being overlapped to an ever-increasing degree.This paper investigates the deformation response of double-track overlapped tunnels in Tianjin,China using finite element analysis(FEA)and field monitoring,considering the attributes of different tunneling forms.With respect to the upper tunneling,the results of the FEA and field monitoring showed that the maximum vertical displacements of the ground surface during the tail passage were 2.06 mm,2.25 mm and 2.39 mm obtained by the FEA,field monitoring and Peck calculation,respectively;the heaves on the vertical displacement curve were observed at 8 m(1.25D,where D is the diameter of the tunnel)away from the center of the tunnel and the curve at both sides was asymmetrical.Furthermore,the crown and bottom produce approximately0.38 mm and 1.26 mm of contraction,respectively.The results of the FEA of the upper and lower sections demonstrated that the tunneling form has an obvious influence on the deformation response of the double-track overlapped tunnel.Compared with the upper tunneling,the lower tunneling exerted significantly less influence on the deformation response,which manifested as a smaller displacement of the strata and deformation of the existing tunnel.The results of this study on overlapped tunnels can provide a reference for similar projects in the future.
基金supported by the National Natural Science Foundation of China under Grants No.61373124
文摘Capacity reduction is a major problem faced by wireless mesh networks. An efficient way to alleviate this problem is proper channel assignment. Current end-toend channel assignment schemes usually focus on the case where channels in distinct frequency bands are assigned to mesh access and backbone, but actually backbone network and access network can use the same IEEE 802.11 technology. Besides, these channel assignment schemes only utilize orthogonal channels to perform channel assignment, and the resulting network interference dramatically degrades network performance. Moreover, Internet-oriented traffic is considered only, and peerto-peer traffic is omitted, or vice versa. The traffic type does not match the practical network. In this paper, we explore how to exploit partially overlapped channels to perform endto-end channel assignment in order to achieve effective end-to-end flow transmissions. The proposed flow-based end-to-end channel assignment schemes can conquer the limitations aforementioned. Simulations reveal that loadaware channel assignment can be applied to networks with stable traffic load, and it can achieve near-optimal performance; Traffic-irrelevant channel assignment is suitable for networks with frequent change of traffic load,and it can achieve good balance between performance and overhead. Also, partially overlapped channels' capability of improving network performance is situation-dependent, they should be used carefully.
文摘A new digital communication technology based on the Phase-Offset Overlapped Waves (POOW) has been introduced in this letter. The waves can be considered as a special multicarrier different from traditional ones. The sub-waves in a coded word's period of the POOW are sine waves and have the same frequencies, but different starting phases. The most important characteristic is that these sub-waves are the piecewise functions and not orthogonal in a code word period. The decoding can be implemented by solving a linear equation group. This code has very high efficiency and thus the data transmission rate is increased greatly.
基金funded By Key Scientific And Technological Program Of Ningbo City(No.2021Z108)Yongjiang Talent Introduction Programme(No.2021A-154-G).
文摘The movement mode of snakes is crawling,and the living environment of snakes with numerous branches and stones will cause plenty of wear for the snake scales.There are plenty of surface structures and morphology on snake scales to avoid severe wear.Among them,the research towards the keeled structure on snake scales is missing.Therefore,in this research,the wear resistance improvement of the keeled structure on the snake scales and the overlapped distribution of snake scales are investigated.The keeled and smooth snake scales were 3D printed and they were distributed on the substrate in the overlapped or paralleled ways.Besides these four samples with keeled/smooth scales and overlapped/paralleled distributed,there is also a reference sample with the same thickness.Based on the tribology test,the number of grooves of samples with the keeled structures is higher than that of samples with smooth surfaces,which indicates that the keeled structure dramatically enhances the wear resistance of snake scales,especially during the wear in the vertical direction.The experiment on surface morphology greatly compromised the result of the tribology test.In addition,the bottom portion of the keeled snake scales can be protected by the keeled structure.Besides,the overlapped distribution can protect the central region of snake scales and provide double-layer protection of the snake body.Overall,the keeled structure and the overlapped distribution play a significant part in the improvement of wear resistance of the snake skin.These findings can enhance the knowledge of the reptiles-mimic surface structure and facilitate the application of military uniforms under high-wear conditions.
基金Thanks to the National Natural Science Foundation of China under Grant No.61702387 for the support of the research in this paper.
文摘This paper investigates a wireless system with multi-Unmanned Aerial Vehicles(UAVs)for improving the overall throughput.In contrast to previous studies that optimize the locations of UAVs and channel assignment separately,this paper considers the two issues jointly by exploiting Partially Overlapped Channels(POCs).The optimization problem of maximizing network throughput is formulated as a non-convex and non-linear problem.In order to find a practical solution,the problem is decomposed into two subproblems,which are iteratively optimized.First,the optimal locations of UAVs are determined under a fixed channel assignment scheme by solving the mixed-integer second-order cone problem.Second,an efficient POC allocation scheme is determined via the proposed channel assignment algorithm.Simulation results show that the proposed approach not only significantly improves system throughput and service reliability compared with the cases in which only orthogonal channels and stationary UAVs are considered,but also achieves similar performance using the exhaustive search algorithm with lower time complexity.
文摘This paper presents a novel architecture of combining the linear array of antenna elements, where each antenna element has digitally selectable true time-delays as weights. Use of time-delays for beam-formation inherently makes the phased array network a wideband system. In particular, this technique envisage a new method of sharing antenna elements, by fixed overlapped sub-array architecture, which is able to maintain permissible element spacing to avoid grating lobe in antenna pattern. Moreover, this scheme additionally offers an easier null steering capability to the subarray architecture. This method essentially eliminates the need for intensive computation of complex weight vectors attached to each antenna element.
文摘This paper presents an innovative eccentric jacket substructure for offshore wind turbines to better withstand intense environmental forces and to replace conventional X-braced jackets in seismically active areas. The proposed eccentric jacket comprises of completely overlapped joint at every joint connection. The joint consists of a chord and two braces in a single plane. The two braces are fully overlapped with a short segment of the diagonal brace welded directly onto the chord. The characteristic feature of this joint configuration is that the short segment member can be designed to absorb and dissipate energy under cyclic load excitation. The experimental and numerical study revealed that the completely overlapped joint performed better in terms of strength resistance, stiffness, ductility, and energy absorption capacity than the conventional gap joints commonly found in typical X-braced jacket framings. The eccentric jacket could also be designed to becoming less stiff, with an inelastic yielding and local buckling of short segment member, so as to better resist the cyclic load generated from intense environmental forces and earthquake. From the design economics, the eccentric jacket provided a more straightforward fabrication with reduced number of welded joints and shorter thicker wall cans than the conventional X-braced jacket. It can therefore be concluded based on the results presented in the study that by designing the short segment member in accordance with strength and ductility requirement,the eccentric jacket substructure supporting the wind turbine could be made to remain stable under gravity loads and to sustain a significantly large amount of motion in the event of rare and intense earthquake or environmental forces, without collapsing.
文摘A nested genetic algorithm, including genetic parameter level and genetic implemented level for peak parameters, was proposed and applied for resolving overlapped spectral bands. By the genetic parameter level, parameters of generic algorithm were optimized; moreover, the number of overlapped peaks was determined simultaneously Then parameters of individual peaks were computed with the genetic implemented level.
基金We thank the National Natural Science Foundation of China(Project No.29975033)the NSF of Guangdong Province(Project No.980340)for financial support.
文摘A new method called spline convolution (SC) for resolving overlapped peaks was proposed in this paper. The differential pulse voltammetric overlapped peaks of mixtures of Pb(II) and Tl(I) were investigated by this method, and satisfactory results were obtained. The results show excellent correlation between peak areas of the processed signals and the concentrations.
文摘With the development of China's social economy,transfer of rural labors,and rise of labor costs,the rice production technologies are changing from manual operation to mechanical operation.The core of mechanical rice production is mechanical planting,while the key to mechanical planting is the seedling raising.On the basis of analyzing and studying the problems and experience of traditional mechanical transplanting of rice,a new overlapped tray seedling raising model was introduced.Main features of this model: substrate seedling raising and overlapped seedling tray.The seedling trays for seeding line are overlapped,and the overlapped trays are moved into the seedling room with controlled temperature and humidity.The temperature of the seedling room is controlled at 30-32℃,and the humidity of the seedling room is controlled at above 90%.After about 48 h,when the seedling height reaches 0.5 cm,move the seedling trays to the nursery.This model consists of one seeding center( seedling raising center) and N nurseries,to realize 1 + N seedling raising for mechanical transplanting of rice.One seeding center can provide seedlings for several hundred to several thousand hectares of mechanical transplanting of rice,and provide a new model for social services.This model could improve the quality of seedlings,increase the seedling survival rate by about 20%,reduce the seedling raising costs by 15%-20%,reduce the seedling raising risks,and greatly increase the utilization rate of the site and equipment of seedling raising center.
基金by the Institutional Review Board of Saga University Hospital(Approval No.2020-05-R-02).
文摘BACKGROUND Overlapped esophagojejunostomy(OEJ) is a secure purely laparoscopic reconstruction after laparoscopic total gastrectomy(LTG). However, long-term surgical results have not been documented well.AIM In this paper, we report unusual patients who manifested jejunal limb stricture near the esophageal hiatus without anastomotic stenosis during long-term observation after surgery.METHODS From April 2009 until May 2020, we retrospectively reviewed 211 patients underwent LTG following by OEJ for gastric carcinoma and took a standard surveillance program. We aimed to characterize a novel complicated disorder observed in these patients to assist treatment and prevention.RESULTS Five patients(2.4%) had unusual jejunal limb stricture after LTG and OEJ,occurring at a mean of 10 mo after initial radical LTG. All five patients had disturbed oral intake and marked weight loss, and two had aspiration pneumonia.Various diagnostic modalities and intraoperative findings in each patient revealed an intact anastomosis, bent or tortuous jejunal limb resulting from loose fibrous adhesions on the left crus at the esophageal hiatus and no cancer recurrence. All five patients were successfully treated by reoperation for adhesiolysis, division of the left crus and rearrangement of the jejunal limb.CONCLUSION Disturbed passage through the jejunal limb near the hiatus can occur after some types of OEJ following LTG. We speculate that it may result from a short remnant esophagus, excessive mobilization of the jejunal limb that permits bending or tortuosity and adhesions on the left crus at the hiatus. Prevention for this complication is possible during the original LTG procedure.
