Product storage policy, single picking volume and picking routing are the three factors of vital importance that affect the efficiency of a crane to pick goods in automated storage and retrieval systems(AS/RS). Compar...Product storage policy, single picking volume and picking routing are the three factors of vital importance that affect the efficiency of a crane to pick goods in automated storage and retrieval systems(AS/RS). Comparative experiments on picking efficiency were conducted targeting picking operation with order of 1 to 20. Based on dedicated and random storage policies, 4 picking methods of patching-based, S-type, return-type and optimized-type routes were used and compared in the experiments. The results show that either the dedicated policy or the random policy was applied, crane worked most efficiently with optimizedtype route, followed by S-type path, patching-based path, and return-type path. When the number of orders in a single picking is larger(more than 5), the random storage policy is preferable to the dedicated policy.展开更多
This paper proposes a solution to the open vehicle routing problem with time windows(OVRPTW)considering third-party logistics(3PL).For the typical OVRPTW problem,most researchers consider time windows,capacity,routing...This paper proposes a solution to the open vehicle routing problem with time windows(OVRPTW)considering third-party logistics(3PL).For the typical OVRPTW problem,most researchers consider time windows,capacity,routing limitations,vehicle destination,etc.Most researchers who previously investigated this problem assumed the vehicle would not return to the depot,but did not consider its final destination.However,by considering 3PL in the B2B e-commerce,the vehicle is required back to the nearest 3PL location with available space.This paper formulates the problem as a mixed integer linear programming(MILP)model with the objective of minimizing the total travel distance.A coordinate representation particle swarm optimization(CRPSO)algorithm is developed to obtain the best delivery sequencing and the capacity of each vehicle.Results of the computational study show that the proposed method provides solution within a reasonable amount of time.Finally,the result compared to PSO also indicates that the CRPSO is effective.展开更多
Objective:To systematically evaluate the spectrum of models providing dedicated resources for emergency urological patients(EUPs).Methods:A search of Cochrane,Embase,Medline and grey literature from January 1,2000 to ...Objective:To systematically evaluate the spectrum of models providing dedicated resources for emergency urological patients(EUPs).Methods:A search of Cochrane,Embase,Medline and grey literature from January 1,2000 to March 26,2019 was performed using methods pre-published on PROSPERO.Reporting followed Preferred Reporting Items for Systematic Review and meta-analysis guidelines.Eligible studies were articles or abstracts published in English describing dedicated models of care for EUPs,which reported at least one secondary outcome.Studies were excluded if they examined pathways dedicated only to single presentations,such as torsion,or outpatient solutions,such as rapid access clinics.The primary outcome was the spectrum of models.Secondary outcomes were time-to-theatre,length of stay,complications and cost.Results:Seven studies were identified,totalling 487 patients.Six studies were conference abstracts,while one study was of full-text length but published in grey literature.Four distinct models were described.These included consultant urologists allocated solely to the care of EUPs(“Acute Urological Unit”)or dedicated registrars or operating theatres(“Hybrid structures”).In some services,EUPs bypassed emergency department assessment and were referred directly to urology(“Urological Assessment Unit”)or were managed by other dedicated means.Allocating services to EUPs was associated with reduced time-to-theatre,length of stay and hospital cost,and improved supervision of junior medical staff.Conclusion:Multiple dedicated models of care exist for EUPs.Low-level evidence suggests these may improve outcomes for patients,staff and hospitals.Higher quality studies are required to explore patient outcomes and minimum requirements to establish these models.展开更多
There have been many advances in the diagnosis and management of focal epilepsies particularly with neuroimaging techniques and magnetic resonance imaging(MRI).Special MRI sequences can be employed to localize and res...There have been many advances in the diagnosis and management of focal epilepsies particularly with neuroimaging techniques and magnetic resonance imaging(MRI).Special MRI sequences can be employed to localize and resect the epileptogenic lesions responsible for focal epilepsy.This study aims to show the benefit of dedicated epilepsy MRI sequences in the diagnosis of focal epilepsies.A general electric 1.5 Tesla MRI machine was used with standard and special sequences.Also,a Nihon Kohden electroencephalography(EEG)machine was used.This is a prospective observational study that included 51 patients with focal epilepsies who had an initial negative brain imaging.They underwent epilepsy MRI sequences along with a prolonged video EEG monitoring to localize the lesion,and then results were analyzed statistically using SPSS 22 program.The majority of patients were males(62.75%)with a mean age of 30 years.The grand majority of patients(74.5%,p value of 0.001)had their lesion localized by the epilepsy MRI.The most commonly found pathology was mesial temporal sclerosis.A significant number of patients(23.5%)were sent for an epilepsy surgery(p value 0.002).This study shows the significant impact of dedicated epilepsy MRI sequences on the diagnosis and management of focal epilepsy in the Lebanese population.展开更多
Dedicated software systems hold a character of individual solutions that entail particular problems with regard to their cost estimation. Thus for many years now objective and reliable approaches to the cost estimatio...Dedicated software systems hold a character of individual solutions that entail particular problems with regard to their cost estimation. Thus for many years now objective and reliable approaches to the cost estimation of such systems have been sought out so that they could provide the possibility to make rational investment decisions concerning those systems. The purpose of this paper is to bring in the approach to cost estimation of dedicated software systems that has been recently growing in global popularity, using it as a background for presenting conclusions resulting from practical verification of author’s own model of dedicated software system cost estimation based on that approach.展开更多
Network slicing is one of the most important concepts in 5G networks. It is enabled by the Network Function Virtualization (NFV) technology to allow a set of Virtual Network Functions (VNFs) to be interconnected to fo...Network slicing is one of the most important concepts in 5G networks. It is enabled by the Network Function Virtualization (NFV) technology to allow a set of Virtual Network Functions (VNFs) to be interconnected to form a Network Service (NS). When network slices are created in 5G, some are shared among different 5G services while the others are dedicated to specific 5G services. The latter are called dedicated slices. Dedicated slices can be constructed with different configurations. In this research, dedicated slices of different configurations in 5G Core were evaluated in order to discover which one would perform better than the others. The performance of three systems would be compared: 1) Free5GC Stage 2 with each dedicated slice consisting of only UPF;2) Free5GC Stage 3 with each dedicated slice consisting of only UPF;3) Free5GC Stage 3 with each dedicated slice consisting of both SMF and UPF in terms of their registration time, response time, throughput, resource cost, and CPU utilization. It is shown that not one of the above systems will always be the best choice;based on the requirements, a specific system may be the best under a specific situation.展开更多
Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly conce...Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly concertos, symphonies, operas and other large works, technical approach and structure used is quite complex, people are left with a deep impression. But it works, while small piano pieces, also has music research value, "dedicated to Alice" is one of the few Beethoven piano pieces. This paper focuses on creative background "dedicated to Alice," this elaborate piano works by the complexity of the analysis of the structure of this work is that it reflects the author' s ideological soul to explore their musical value.展开更多
SU Moying, of Sheke Village, S h e k e To w n s h i p , Lanxian County, Shanxi Province, has been teaching in the countryside for 20 of her 48 years. She
The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can ...The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can be widely used in not only concerning utilities but also manufacturers and research / certification institutes because of its many functions. The hardware architecture and software implementation of the simulator are described. The main features and functions of the simulator are also展开更多
<strong>Background:</strong> The diverse modes in geographical locations, environmental factors, genetic and racial characteristics play a complex role in determining the pattern of neurological disorders ...<strong>Background:</strong> The diverse modes in geographical locations, environmental factors, genetic and racial characteristics play a complex role in determining the pattern of neurological disorders worldwide. Determining the pattern of neurological disorders enables health policymakers to plan evidently for service, training, and research priorities. Few prevalence studies in neurology were conducted in Sudan. <strong>Methods:</strong> This is a retrospective hospital-based study that reviewed the medical records of patients who attended a Dedicated Neurology Clinic (DNC) in Omdurman, the national Capital of Sudan, for 24 months, from January 2016 to January 2018. This study aimed to determine the DNC pattern of neurological disorders as a representative subset prevalence in Sudan. Neurologists conducted the medical workup for diagnosis after at least two visits. All patients have ethically consented. <strong>Results: </strong>The total number of patients was 1050. Only 749 patients (71.3%) fulfilled the inclusion criteria. The mean age was 46.5 ± 1.9, and males were 45.3%. 72% were from the Capital. The presenting symptoms were headache (16.6%), seizures (11.5%), limbs weakness (11.2%), and lower percentages for other neurological symptoms. The commonest diagnoses were Stroke 12.4%, Epilepsy 9.3%, Primary Headache 8.8%, Movement Disorders 7.3%, Peripheral Neuropathy 6%, Dementia 4% Neuroinfections 1.4%, Demyelinating Disorders 2.6%, Spinal Spondylotic Radiculopathy 2.6% and 1.7% for Cerebral Venous Thrombosis. <strong>Conclusion:</strong> The data from Sudan-DNC showed that the most common neurological disorders descendingly were Stroke, Epilepsy, Headache, Movement Disorders, Peripheral Neuropathy, Dementia, Infections, Demyelinating Disorders, Spinal Spondylotic Radiculopathy, and Cerebral Venous Thrombosis. The demyelinating disorders and peripheral neuropathy showed a higher percentage than our previous preliminary prevalence study in 2012 compared to the other conditions, which showed similar rates in that study.展开更多
Rich burn industrial natural gas engines offer best in class post catalyst emissions by using a non-selective catalyst reduction aftertreatment technology. However, they operate with reduced power density when compare...Rich burn industrial natural gas engines offer best in class post catalyst emissions by using a non-selective catalyst reduction aftertreatment technology. However, they operate with reduced power density when compared to lean burn engines. Dedicated exhaust gas recirculation (EGR) offers a possible pathway for rich burn engines to use non-selective catalyst reduction aftertreatment technology without sacrificing power density. In order to achieve best in class post catalyst emissions, the precious metals and washcoat of a non-selective catalyst must be designed according to the expected exhaust composition of an engine. In this work, a rich burn industrial natural gas engine operating with dedicated EGR was paired with a commercially available non-selective catalyst. At rated brake mean effective pressure (BMEP) the air-fuel ratio was swept between rich and lean conditions to compare the catalyst reduction efficiency and post catalyst emissions of rich burn and dedicated EGR combustion. It was found that due to low oxides of nitrogen (NO<sub>x</sub>) emissions across the entire air-fuel ratio range, dedicated EGR offers a much larger range of air-fuel ratios where low regulated emissions can be met. Low engine out NO<sub>x</sub> also points towards a possibility of using an oxidation catalyst rather than a non-selective catalyst for dedicated EGR applications. The location of the NO<sub>x</sub>-CO tradeoff was shifted to more rich conditions using dedicated EGR.展开更多
On the afternoon of 21 December, 2006, Uli Schwarz, professor emeritus of the German Max Planck Society (MPG) and founding director of the CAS Shanghai Institute for Advanced Stud-
The two-stage transcritical CO_(2) refrigeration cycle with dedicated dual-subcooling and mechanical recooling is proposed.The inter-stage pressure is critical for such cycle performances;however,it has not been studi...The two-stage transcritical CO_(2) refrigeration cycle with dedicated dual-subcooling and mechanical recooling is proposed.The inter-stage pressure is critical for such cycle performances;however,it has not been studied exactly.Therefore,the research aim is to disclose the effect of inter-stage pressure on performances of the proposed cycle.The main work consists of four aspects.Firstly,the comparative study is performed to display advantages of the proposed cycle.Secondly,the key temperatures,heat and power consumptions as well as performance indicators for different inter-stage pressures are analyzed in detail,based on the parametric model.Thirdly,the optimal inter-stage pressure for different conditions is obtained by the nonlinear direct search method.Finally,the economic performance is assessed.It is found that the compressor power of the proposed cycle drops by 12%,and the working temperature lower limit is reduced by 11℃.Furthermore,it is considered that the optimal inter-stage pressure is insensitive to the heat source temperature.The novelty lies in illustrating the effect of inter-stage pressure,obtaining trends of the optimal value,and pointing out the system feasibility.The paper is favorable for design and operation optimization of the proposed system.展开更多
The great diversity of dedicated hybrid transmissions(DHTs)requires a method to identify solutions among all potential concepts involved in each structure.Therefore,a DHT synthesis tool is developed on the basis of ge...The great diversity of dedicated hybrid transmissions(DHTs)requires a method to identify solutions among all potential concepts involved in each structure.Therefore,a DHT synthesis tool is developed on the basis of general transmission synthesis.In the first synthesis step,transmission structures are generated with only conventional functions such as driving with only the internal combustion engine.Electric machines are then installed in the transmissions to achieve further hybrid functions,including boosting,eCVT and electric driving modes.The number of generated transmission concepts increases exponentially with each synthesis step.Various evaluations are carried out successively to identify the most suitable DHT concepts among the many possible solutions.The generated DHT concepts are evaluated in terms of structural feasibility,driving modes,drivability and load factors on transmission components.An example of DHT synthesis involving planetary gear sets is explained in detail.The best five DHT structures are identified out of more than 120 billion solutions.展开更多
A dedicated breast CT system (DBCT) is a new method for breast cancer detection proposed in recent years. In this paper, the glandular dose in the DBCT is simulated using the Monte Carlo method. The phantom shape is...A dedicated breast CT system (DBCT) is a new method for breast cancer detection proposed in recent years. In this paper, the glandular dose in the DBCT is simulated using the Monte Carlo method. The phantom shape is half ellipsoid, and a series of phantoms with different sizes, shapes and compositions were constructed. In order to optimize the spectra, monoenergy X-ray beams of 5-80 keV were used in simulation. The dose distribution of a breast phantom was studied: a higher energy beam generated more uniform distribution, and the outer parts got more dose than the inner parts. For polyenergtic spectra, four spectra of A1 filters with different thicknesses were simulated, and the polyenergtic glandular dose was calculated as a spectral weighted combination of the monoenergetic dose.展开更多
Purpose–This study aims to make full use of the advantages of connected and autonomous vehicles(CAVs)and dedicated CAV lanes to ensure all CAVs can pass intersections without stopping.Design/methodology/approach–The...Purpose–This study aims to make full use of the advantages of connected and autonomous vehicles(CAVs)and dedicated CAV lanes to ensure all CAVs can pass intersections without stopping.Design/methodology/approach–The authors developed a signal coordination model for arteries with dedicated CAV lanes by using mixed integer linear programming.CAV non-stop constraints are proposed to adapt to the characteristics of CAVs.As it is a continuous problem,various situations that CAVs arrive at intersections are analyzed.The rules are discovered to simplify the problem by discretization method.Findings–A case study is conducted via SUMO traffic simulation program.The results show that the efficiency of CAVs can be improved significantly both in high-volume scenario and medium-volume scenario with the plan optimized by the model proposed in this paper.At the same time,the progression efficiency of regular vehicles is not affected significantly.It is indicated that full-scale benefits of dedicated CAV lanes can only be achieved with signal coordination plans considering CAV characteristics.Originality/value–To the best of the authors’knowledge,this is the first research that develops a signal coordination model for arteries with dedicated CAV lanes.展开更多
基金Funded by National Social Science Foundation of China(16CGL018)the Soft Science Research Funds for Chengdu Science and Technology Project(2015-RK00-00206-ZF)the National United Engineering Laboratory of Integrated and Intelligent Transportation,Southwest Jiaotong University,China
文摘Product storage policy, single picking volume and picking routing are the three factors of vital importance that affect the efficiency of a crane to pick goods in automated storage and retrieval systems(AS/RS). Comparative experiments on picking efficiency were conducted targeting picking operation with order of 1 to 20. Based on dedicated and random storage policies, 4 picking methods of patching-based, S-type, return-type and optimized-type routes were used and compared in the experiments. The results show that either the dedicated policy or the random policy was applied, crane worked most efficiently with optimizedtype route, followed by S-type path, patching-based path, and return-type path. When the number of orders in a single picking is larger(more than 5), the random storage policy is preferable to the dedicated policy.
文摘This paper proposes a solution to the open vehicle routing problem with time windows(OVRPTW)considering third-party logistics(3PL).For the typical OVRPTW problem,most researchers consider time windows,capacity,routing limitations,vehicle destination,etc.Most researchers who previously investigated this problem assumed the vehicle would not return to the depot,but did not consider its final destination.However,by considering 3PL in the B2B e-commerce,the vehicle is required back to the nearest 3PL location with available space.This paper formulates the problem as a mixed integer linear programming(MILP)model with the objective of minimizing the total travel distance.A coordinate representation particle swarm optimization(CRPSO)algorithm is developed to obtain the best delivery sequencing and the capacity of each vehicle.Results of the computational study show that the proposed method provides solution within a reasonable amount of time.Finally,the result compared to PSO also indicates that the CRPSO is effective.
基金supported by the Adelaide Graduate Centre of the University of AdelaideUniversity of Adelaide divisional scholarship(UoA2018)+1 种基金a Hospital Research Foundation post-graduate scholarship(2018/6330)a National Health and Medical Research Council post-graduate scholarship(1169487)in relation to this work.
文摘Objective:To systematically evaluate the spectrum of models providing dedicated resources for emergency urological patients(EUPs).Methods:A search of Cochrane,Embase,Medline and grey literature from January 1,2000 to March 26,2019 was performed using methods pre-published on PROSPERO.Reporting followed Preferred Reporting Items for Systematic Review and meta-analysis guidelines.Eligible studies were articles or abstracts published in English describing dedicated models of care for EUPs,which reported at least one secondary outcome.Studies were excluded if they examined pathways dedicated only to single presentations,such as torsion,or outpatient solutions,such as rapid access clinics.The primary outcome was the spectrum of models.Secondary outcomes were time-to-theatre,length of stay,complications and cost.Results:Seven studies were identified,totalling 487 patients.Six studies were conference abstracts,while one study was of full-text length but published in grey literature.Four distinct models were described.These included consultant urologists allocated solely to the care of EUPs(“Acute Urological Unit”)or dedicated registrars or operating theatres(“Hybrid structures”).In some services,EUPs bypassed emergency department assessment and were referred directly to urology(“Urological Assessment Unit”)or were managed by other dedicated means.Allocating services to EUPs was associated with reduced time-to-theatre,length of stay and hospital cost,and improved supervision of junior medical staff.Conclusion:Multiple dedicated models of care exist for EUPs.Low-level evidence suggests these may improve outcomes for patients,staff and hospitals.Higher quality studies are required to explore patient outcomes and minimum requirements to establish these models.
文摘There have been many advances in the diagnosis and management of focal epilepsies particularly with neuroimaging techniques and magnetic resonance imaging(MRI).Special MRI sequences can be employed to localize and resect the epileptogenic lesions responsible for focal epilepsy.This study aims to show the benefit of dedicated epilepsy MRI sequences in the diagnosis of focal epilepsies.A general electric 1.5 Tesla MRI machine was used with standard and special sequences.Also,a Nihon Kohden electroencephalography(EEG)machine was used.This is a prospective observational study that included 51 patients with focal epilepsies who had an initial negative brain imaging.They underwent epilepsy MRI sequences along with a prolonged video EEG monitoring to localize the lesion,and then results were analyzed statistically using SPSS 22 program.The majority of patients were males(62.75%)with a mean age of 30 years.The grand majority of patients(74.5%,p value of 0.001)had their lesion localized by the epilepsy MRI.The most commonly found pathology was mesial temporal sclerosis.A significant number of patients(23.5%)were sent for an epilepsy surgery(p value 0.002).This study shows the significant impact of dedicated epilepsy MRI sequences on the diagnosis and management of focal epilepsy in the Lebanese population.
文摘Dedicated software systems hold a character of individual solutions that entail particular problems with regard to their cost estimation. Thus for many years now objective and reliable approaches to the cost estimation of such systems have been sought out so that they could provide the possibility to make rational investment decisions concerning those systems. The purpose of this paper is to bring in the approach to cost estimation of dedicated software systems that has been recently growing in global popularity, using it as a background for presenting conclusions resulting from practical verification of author’s own model of dedicated software system cost estimation based on that approach.
文摘Network slicing is one of the most important concepts in 5G networks. It is enabled by the Network Function Virtualization (NFV) technology to allow a set of Virtual Network Functions (VNFs) to be interconnected to form a Network Service (NS). When network slices are created in 5G, some are shared among different 5G services while the others are dedicated to specific 5G services. The latter are called dedicated slices. Dedicated slices can be constructed with different configurations. In this research, dedicated slices of different configurations in 5G Core were evaluated in order to discover which one would perform better than the others. The performance of three systems would be compared: 1) Free5GC Stage 2 with each dedicated slice consisting of only UPF;2) Free5GC Stage 3 with each dedicated slice consisting of only UPF;3) Free5GC Stage 3 with each dedicated slice consisting of both SMF and UPF in terms of their registration time, response time, throughput, resource cost, and CPU utilization. It is shown that not one of the above systems will always be the best choice;based on the requirements, a specific system may be the best under a specific situation.
文摘Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly concertos, symphonies, operas and other large works, technical approach and structure used is quite complex, people are left with a deep impression. But it works, while small piano pieces, also has music research value, "dedicated to Alice" is one of the few Beethoven piano pieces. This paper focuses on creative background "dedicated to Alice," this elaborate piano works by the complexity of the analysis of the structure of this work is that it reflects the author' s ideological soul to explore their musical value.
文摘SU Moying, of Sheke Village, S h e k e To w n s h i p , Lanxian County, Shanxi Province, has been teaching in the countryside for 20 of her 48 years. She
文摘The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can be widely used in not only concerning utilities but also manufacturers and research / certification institutes because of its many functions. The hardware architecture and software implementation of the simulator are described. The main features and functions of the simulator are also
文摘<strong>Background:</strong> The diverse modes in geographical locations, environmental factors, genetic and racial characteristics play a complex role in determining the pattern of neurological disorders worldwide. Determining the pattern of neurological disorders enables health policymakers to plan evidently for service, training, and research priorities. Few prevalence studies in neurology were conducted in Sudan. <strong>Methods:</strong> This is a retrospective hospital-based study that reviewed the medical records of patients who attended a Dedicated Neurology Clinic (DNC) in Omdurman, the national Capital of Sudan, for 24 months, from January 2016 to January 2018. This study aimed to determine the DNC pattern of neurological disorders as a representative subset prevalence in Sudan. Neurologists conducted the medical workup for diagnosis after at least two visits. All patients have ethically consented. <strong>Results: </strong>The total number of patients was 1050. Only 749 patients (71.3%) fulfilled the inclusion criteria. The mean age was 46.5 ± 1.9, and males were 45.3%. 72% were from the Capital. The presenting symptoms were headache (16.6%), seizures (11.5%), limbs weakness (11.2%), and lower percentages for other neurological symptoms. The commonest diagnoses were Stroke 12.4%, Epilepsy 9.3%, Primary Headache 8.8%, Movement Disorders 7.3%, Peripheral Neuropathy 6%, Dementia 4% Neuroinfections 1.4%, Demyelinating Disorders 2.6%, Spinal Spondylotic Radiculopathy 2.6% and 1.7% for Cerebral Venous Thrombosis. <strong>Conclusion:</strong> The data from Sudan-DNC showed that the most common neurological disorders descendingly were Stroke, Epilepsy, Headache, Movement Disorders, Peripheral Neuropathy, Dementia, Infections, Demyelinating Disorders, Spinal Spondylotic Radiculopathy, and Cerebral Venous Thrombosis. The demyelinating disorders and peripheral neuropathy showed a higher percentage than our previous preliminary prevalence study in 2012 compared to the other conditions, which showed similar rates in that study.
文摘Rich burn industrial natural gas engines offer best in class post catalyst emissions by using a non-selective catalyst reduction aftertreatment technology. However, they operate with reduced power density when compared to lean burn engines. Dedicated exhaust gas recirculation (EGR) offers a possible pathway for rich burn engines to use non-selective catalyst reduction aftertreatment technology without sacrificing power density. In order to achieve best in class post catalyst emissions, the precious metals and washcoat of a non-selective catalyst must be designed according to the expected exhaust composition of an engine. In this work, a rich burn industrial natural gas engine operating with dedicated EGR was paired with a commercially available non-selective catalyst. At rated brake mean effective pressure (BMEP) the air-fuel ratio was swept between rich and lean conditions to compare the catalyst reduction efficiency and post catalyst emissions of rich burn and dedicated EGR combustion. It was found that due to low oxides of nitrogen (NO<sub>x</sub>) emissions across the entire air-fuel ratio range, dedicated EGR offers a much larger range of air-fuel ratios where low regulated emissions can be met. Low engine out NO<sub>x</sub> also points towards a possibility of using an oxidation catalyst rather than a non-selective catalyst for dedicated EGR applications. The location of the NO<sub>x</sub>-CO tradeoff was shifted to more rich conditions using dedicated EGR.
文摘On the afternoon of 21 December, 2006, Uli Schwarz, professor emeritus of the German Max Planck Society (MPG) and founding director of the CAS Shanghai Institute for Advanced Stud-
基金supported by National Foreign Expert Projectunderthecontract No.G2022163009LGuangdong Basic and Applied Basic Research Foundation under the contract No.2023A1515011337+1 种基金Zhuhai Industry-University-Research Cooperation Project under the contract No.ZH22017001210017PWCKey Laboratory of Efficient and Clean Energy Utilization of Guangdong Higher Education Institutes underthecontract No.KLB10004.
文摘The two-stage transcritical CO_(2) refrigeration cycle with dedicated dual-subcooling and mechanical recooling is proposed.The inter-stage pressure is critical for such cycle performances;however,it has not been studied exactly.Therefore,the research aim is to disclose the effect of inter-stage pressure on performances of the proposed cycle.The main work consists of four aspects.Firstly,the comparative study is performed to display advantages of the proposed cycle.Secondly,the key temperatures,heat and power consumptions as well as performance indicators for different inter-stage pressures are analyzed in detail,based on the parametric model.Thirdly,the optimal inter-stage pressure for different conditions is obtained by the nonlinear direct search method.Finally,the economic performance is assessed.It is found that the compressor power of the proposed cycle drops by 12%,and the working temperature lower limit is reduced by 11℃.Furthermore,it is considered that the optimal inter-stage pressure is insensitive to the heat source temperature.The novelty lies in illustrating the effect of inter-stage pressure,obtaining trends of the optimal value,and pointing out the system feasibility.The paper is favorable for design and operation optimization of the proposed system.
文摘The great diversity of dedicated hybrid transmissions(DHTs)requires a method to identify solutions among all potential concepts involved in each structure.Therefore,a DHT synthesis tool is developed on the basis of general transmission synthesis.In the first synthesis step,transmission structures are generated with only conventional functions such as driving with only the internal combustion engine.Electric machines are then installed in the transmissions to achieve further hybrid functions,including boosting,eCVT and electric driving modes.The number of generated transmission concepts increases exponentially with each synthesis step.Various evaluations are carried out successively to identify the most suitable DHT concepts among the many possible solutions.The generated DHT concepts are evaluated in terms of structural feasibility,driving modes,drivability and load factors on transmission components.An example of DHT synthesis involving planetary gear sets is explained in detail.The best five DHT structures are identified out of more than 120 billion solutions.
基金Supported by Knowledge Innovation Project of Chinese Academy of Sciences (KJCX2-EW-N06)
文摘A dedicated breast CT system (DBCT) is a new method for breast cancer detection proposed in recent years. In this paper, the glandular dose in the DBCT is simulated using the Monte Carlo method. The phantom shape is half ellipsoid, and a series of phantoms with different sizes, shapes and compositions were constructed. In order to optimize the spectra, monoenergy X-ray beams of 5-80 keV were used in simulation. The dose distribution of a breast phantom was studied: a higher energy beam generated more uniform distribution, and the outer parts got more dose than the inner parts. For polyenergtic spectra, four spectra of A1 filters with different thicknesses were simulated, and the polyenergtic glandular dose was calculated as a spectral weighted combination of the monoenergetic dose.
基金supported by“Pioneer”and“Leading Goose”R&D Program of Zhejiang(2022C01042),and Alibaba-Zhejiang University Joint Research Institute of Frontier Technologies.
文摘Purpose–This study aims to make full use of the advantages of connected and autonomous vehicles(CAVs)and dedicated CAV lanes to ensure all CAVs can pass intersections without stopping.Design/methodology/approach–The authors developed a signal coordination model for arteries with dedicated CAV lanes by using mixed integer linear programming.CAV non-stop constraints are proposed to adapt to the characteristics of CAVs.As it is a continuous problem,various situations that CAVs arrive at intersections are analyzed.The rules are discovered to simplify the problem by discretization method.Findings–A case study is conducted via SUMO traffic simulation program.The results show that the efficiency of CAVs can be improved significantly both in high-volume scenario and medium-volume scenario with the plan optimized by the model proposed in this paper.At the same time,the progression efficiency of regular vehicles is not affected significantly.It is indicated that full-scale benefits of dedicated CAV lanes can only be achieved with signal coordination plans considering CAV characteristics.Originality/value–To the best of the authors’knowledge,this is the first research that develops a signal coordination model for arteries with dedicated CAV lanes.