Living-donor liver transplantation has provided a solution to the severe lack of cadaver grafts for the replacement of liver afflicted with end-stage cirrhosis, fulminant disease, or inborn errors of metabolism. Vascu...Living-donor liver transplantation has provided a solution to the severe lack of cadaver grafts for the replacement of liver afflicted with end-stage cirrhosis, fulminant disease, or inborn errors of metabolism. Vascular complications remain the most serious complications and a common cause for graft failure after hepatic transplantation. Doppler ultrasound remains the primary radiological imaging modality for the diagnosis of such complications. This article presents a brief review of intra- and post-operative living donor liver transplantation anatomy and a synopsis of the role of ultrasonography and color Doppler in evaluating the graft vascular haemodynamics both during surgery and post-operatively in accurately defining the early vascular complications. Intra-operative ultrasonography of the liver graft provides the surgeon with useful real-time diagnostic and staging information that may result in an alteration in the planned surgical approach and corrections of surgical complications during the procedure of vascular anastomoses. The relevant intraoperative anatomy and the spectrum of normal and abnormal findings are described. Ultrasonography and color Doppler also provides the clinicians and surgeons early post-operative potential developmental complications that may occur during hospital stay. Early detection and thus early problem solving can make the difference between graft survival and failure.展开更多
Objectives To investigate the causes, theraputic and preventive methods of com- plications associated with transcatheter occlusion of at- rial septal defect ( ASD) using the Amplatzer septal oc- cluder (ASO) in childr...Objectives To investigate the causes, theraputic and preventive methods of com- plications associated with transcatheter occlusion of at- rial septal defect ( ASD) using the Amplatzer septal oc- cluder (ASO) in children. Methods 289 cases un- derwent transcatheter closure of ASD with ASO. Com- plications occurred in 9 cases. The complications in procedure included systemic circulatory systemic air embolism in 2, pulmonary air embolism in 1, pericar- dial tamponade in 1, ASO malposition requiring emer- gency surgical removal in 1, transient atrial extrasysto- les in 1 and sizing balloon rupture in 1 case. 2 cases with postoperative complications were found in the fol- low-up studies. These included perforation of mitral valve and ASO partially dislodged. In this study, 5 children with intraoperative complication received e- mergency therapy including surgical intervention, and others needed only follow-up, as the complications were transient or asymptomatic. Results There were no children death in this study. The 5 cases who re- ceived treatment were completely healing, and the oth- ers with intra - procedure complications were also had no sequela existed. Cases with mitral valve and ASO partially dislodged were still in follow-up studies, as the 2 patients having no symptoms. Conclutions Air embolism were occurred easily in atrial septal defect cases who received ASO therapy. Complications mainly caused by inappropriate operative procedure and some complications needed emergency treatments. Follow-up studies were important to cases with transcatheter oc- clusion therapy.展开更多
Nowadays, picture fuzzy set theory is a flourishing field in mathematics with uncertainty by incorporating the concept of positive, negative and neutral membership degrees of an object. A traditional crisp relation re...Nowadays, picture fuzzy set theory is a flourishing field in mathematics with uncertainty by incorporating the concept of positive, negative and neutral membership degrees of an object. A traditional crisp relation represents the satisfaction or the dissatisfaction of relationship, connection or correspondence between the objects of two or more sets. However, there are some problems that can’t be solved through classical relationships, such as the relationship between two objects being vague. In those situations, picture fuzzy relation over picture fuzzy sets is an important and powerful concept which is suitable for describing correspondences between two vague objects. It represents the strength of association of the elements of picture fuzzy sets. It plays an important role in picture fuzzy modeling, inference and control system and also has important applications in relational databases, approximate reasoning, preference modeling, medical diagnosis, etc. In this article, we define picture fuzzy relations over picture fuzzy sets, including some other fundamental definitions with illustrations. The max-min and min-max compositions of picture fuzzy relations are defined in the light of picture fuzzy sets and discussed some properties related to them. The reflexivity, symmetry and transitivity of a picture fuzzy relation are described over a picture fuzzy set. Finally, various properties are explored related to the picture fuzzy relations over a picture fuzzy set.展开更多
Because of global climate change, it is necessary to add forest biomass estimation to national forest resource monitoring. The biomass equations developed for forest biomass estimation should be compatible with volume...Because of global climate change, it is necessary to add forest biomass estimation to national forest resource monitoring. The biomass equations developed for forest biomass estimation should be compatible with volume equations. Based on the tree volume and aboveground biomass data of Masson pine (Pinus massoniana Lamb.) in southern China, we constructed one-, two- and three-variable aboveground biomass equations and biomass conversion functions compatible with tree volume equations by using error-in-variable simultaneous equations. The prediction precision of aboveground biomass estimates from one variable equa- tion exceeded 95%. The regressions of aboveground biomass equations were improved slightly when tree height and crown width were used together with diameter on breast height, although the contributions to regressions were statistically insignificant. For the biomass conversion function on one variable, the conversion factor decreased with increasing diameter, but for the conversion function on two variables, the conversion factor increased with increasing diameter but decreased with in- creasing tree height.展开更多
Flexible joints are usually used to transfer velocities in robot systems and may lead to delays in motion transformation due to joint flexibility. In this paper, a linkrotor structure connected by a flexible joint or ...Flexible joints are usually used to transfer velocities in robot systems and may lead to delays in motion transformation due to joint flexibility. In this paper, a linkrotor structure connected by a flexible joint or shaft is firstly modeled to be a slow-fast delayed system when moment of inertia of the lightweight link is far less than that of the heavy rotor. To analyze the stability and oscillations of the slowfast system, the geometric singular perturbation method is extended, with both slow and fast manifolds expressed analytically. The stability of the slow manifold is investigated and critical boundaries are obtained to divide the stable and the unstable regions. To study effects of the transformation delay on the stability and oscillations of the link, two quantitatively different driving forces derived from the negative feedback of the link are considered. The results show that one of these two typical driving forces may drive the link to exhibit a stable state and the other kind of driving force may induce a relaxation oscillation for a very small delay. However, the link loses stability and undergoes regular periodic and bursting oscillation when the transformation delay is large. Basically, a very small delay does not affect the stability of the slow manifold but a large delay affects substantially.展开更多
Two constraint violation stabilization methods are presented to solve the Euler Lagrange equations of motion of a multibody system with nonholonomic constraints. Compared to the previous works, the newly devised metho...Two constraint violation stabilization methods are presented to solve the Euler Lagrange equations of motion of a multibody system with nonholonomic constraints. Compared to the previous works, the newly devised methods can deal with more complicated problems such as those with nonholonomic constraints or redundant constraints, and save the computation time. Finally a numerical simulation of a multibody system is conducted by using the methods given in this paper.展开更多
AIM: To assess the value of plasma melatonin in pre-dicting acute pancreatitis when combined with the acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and bedside index for severity in acute pancreatitis ...AIM: To assess the value of plasma melatonin in pre-dicting acute pancreatitis when combined with the acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and bedside index for severity in acute pancreatitis (BISAP) scoring systems. METHODS: APACHEⅡ and BISAP scores were calculated for 55 patients with acute physiology (AP) in the first 24 h of admission to the hospital. Additionally, morning (6:00 AM) serum melatonin concentrations were measured on the first day after admission. According to the diagnosis and treatment guidelines for acute pancreatitis in China, 42 patients suffered mild AP (MAP). The other 13 patients developed severe AP (SAP). A total of 45 healthy volunteers were used in this study as controls. The ability of melatonin and the APACHEⅡ and BISAP scoring systems to predict SAP was evaluated using a receiver operating characteristic (ROC) curve. The optimal melatonin cutoff concentration for SAP patients, based on the ROC curve, was used to classify the patients into either a high concen-tration group (34 cases) or a low concentration group (21 cases). Differences in the incidence of high scores, according to the APACHEⅡ and BISAP scoring sys- tems, were compared between the two groups. RESULTS: The MAP patients had increased melatonin levels compared to the SAP (38.34 ng/L vs 26.77 ng/L) (P = 0.021) and control patients (38.34 ng/L vs 30.73 ng/L) (P = 0.003). There was no significant difference inmelatoninconcentrations between the SAP group and the control group. The accuracy of determining SAP based on the melatonin level, the APACHEⅡ score and the BISAP score was 0.758, 0.872, and 0.906, respectively, according to the ROC curve. A melatonin concentration ≤ 28.74 ng/L was associated with an increased risk of developing SAP. The incidence of high scores (≥ 3) using the BISAP system was significantly higher in patients with low melatonin concentration (≤ 28.74 ng/L) compared to patients with high melatonin concentration (> 28.74 ng/L) (42.9% vs 14.7%, P = 0.02). The incidence of high APACHEⅡ scores (≥ 10) between the two groups was not significantly different. CONCLUSION: The melatonin concentration is closely related to the severity of AP and the BISAP score. Therefore, we can evaluate the severity of disease by measuring the levels of serum melatonin.展开更多
Abstract Problems in agricultural science and technology service system were ana- lyzed, such as system problem, investment and worker quality, and based on this countermeasures were proposed, so as to promote the dev...Abstract Problems in agricultural science and technology service system were ana- lyzed, such as system problem, investment and worker quality, and based on this countermeasures were proposed, so as to promote the development of modern agri- culture and construction of new countryside.展开更多
The accuracy of numerical simulations and many other material design calculations, such as the rolling force, rollingtorque, etc., depends on the description of stress-strain relationship of the deformed materials. On...The accuracy of numerical simulations and many other material design calculations, such as the rolling force, rollingtorque, etc., depends on the description of stress-strain relationship of the deformed materials. One common methodof describing the stress-strain relationship is using constitutive equations, with the unknown parameters fitted byexperimental data obtained via plane strain compression (PSC). Due to the highly nonlinear behaviour of the constitutive equations and the noise included in the PSC data, determination of the model parameters is difficult. Inthis paper, genetic algorithms were exploited to optimise parameters for the constitutive equations based on thePSC data. The original PSC data were processed to generate the stress-strain data, and data pre-processing wascarried out to remove the noise contained in the original PSC data. Several genetic optimisation schemes have beeninvestigated, with different coding schemes and different genetic operators for selection, crossover and mutation.It was found that the real value coded genetic algorithms converged much faster and were more efficient for theparameter optimisation problem.展开更多
The problem of mobile localization for wireless sensor network has attracted considerable attention in recent years. The localization accuracy will drastically grade in non-line of sight(NLOS) conditions. In this pape...The problem of mobile localization for wireless sensor network has attracted considerable attention in recent years. The localization accuracy will drastically grade in non-line of sight(NLOS) conditions. In this paper, we propose a mobile localization strategy based on Kalman filter. The key technologies for the proposed method are the NLOS identification and mitigation. The proposed method does not need the prior knowledge of the NLOS error and it is independent of the physical measurement ways. Simulation results show that the proposed method owns the higher localization accuracy when compared with other methods.展开更多
Rectal cancers extending through the rectal wall, or involving locoregional lymph nodes (T3/4 or N1/2), have been more difficult to cure. The confines of the bony pelvis and the necessity of preserving the autonomic n...Rectal cancers extending through the rectal wall, or involving locoregional lymph nodes (T3/4 or N1/2), have been more difficult to cure. The confines of the bony pelvis and the necessity of preserving the autonomic nerves makes surgical extirpation challenging, which accounts for the high rates of local and distant relapse in this setting. Combined multimodality treatment for rectal cancer stage Ⅱ and Ⅲ was recommended from National Institute of Health consensus. Neoadjuvant chemoradiation using fluoropyrimidine-based regimen prior to surgical resection has emerged as the standard of care in the United States. Optimal time of surgery after neoadjuvant treatment remained unclear and prospective randomized controlled trial is ongoing. Traditionally, 6-8 wk waiting period was commonly used. The accuracy of studies attempting to determine tumor complete response remains problematic. Currently, surgery remains the standard of care for rectal cancer patients following neoadjuvant chemoradiation, where-as observational management is still investigational. In this article, we outline trends and controversies associated with optimal pre-treatment staging, neoadjuvant therapies, surgery, and adjuvant therapy.展开更多
As a part of INDEPTH 3/GEODEPTH geological surface investigations were carried out during two field campaigns in 1998 and 1999. The working area covers a roughly N\|S (30~36°N) tren ding, 200km wide belt through...As a part of INDEPTH 3/GEODEPTH geological surface investigations were carried out during two field campaigns in 1998 and 1999. The working area covers a roughly N\|S (30~36°N) tren ding, 200km wide belt through the Lhasa Terrane and Qiangtang Terrane at a longitude of 88~90°E. Field geology was focused on geological mapping, structural measurements, and extensive sampling for the purpose of fission track geochronology. Additionally a total number of 742 orientated palaeomagnetic samples were drilled at 73 sites. Most of the samples were taken in fine\|grained sediments of Cretaceous, Eocene, and Neogene age. Five sites were drilled in acid to intermediate volcanics.A first sequence of measurements has been applied on a set of specimen. Most of the chosen formations (>80%) have acquired stable remanences which are carried by hematite and magnetite. As an example for the characteristic demagnetising behaviour of fine\|grained probable Cretaceous sandstones see Fig.1a. The unblocking temperature of 650℃ allows to identify hematite as remanence carrier.. Although single sites show well\|defined mean directions (e.g. site 76B: α 95 =3 8; k =185 8) the distribution among several site means of one formation could scatter (Fig.1b). It has to be checked carefully if rotations of single crustal elements are responsible for this effect. There is evidence to assume the detected characteristic remanences to be primary—further analysis including fold tests will be performed after the data set has increased.展开更多
In this paper, we establish travelling wave solutions for some nonlinear evolution equations. The first integral method is used to construct the travelling wave solutions of the modified Benjamin-Bona-Mahony and the c...In this paper, we establish travelling wave solutions for some nonlinear evolution equations. The first integral method is used to construct the travelling wave solutions of the modified Benjamin-Bona-Mahony and the coupled Klein-Gordon equations. The obtained results include periodic and solitary wave solutions. The first integral method presents a wider applicability to handling nonlinear wave equations.展开更多
Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen(CO_(2~–)N_2) mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic(...Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen(CO_(2~–)N_2) mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic(QMD) simulations based on density functional theory including dispersion corrections(DFT-D). We present equilibrium properties of liquid mixture for 112 separate density and temperature points, by selecting densities ranging from ρ = 1.80 g/cm^3 to 3.40 g/cm^3 and temperatures from T = 500 K to 8000 K. In the range of our study, the liquid CO_(2~–)N_2 mixture undergoes a continuous transition from molecular to atomic fluid state and liquid polymerization inferred from pair correlation functions(PCFs)and the distribution of various molecular components. The insulator–metal transition is demonstrated by means of the electronic density of states(DOS).展开更多
5G takes the concept of service-oriented architecture to replace the priority principle of network efficiency in the Internet to meet requirements of the industrial Internet and smart cities,such as high reliability a...5G takes the concept of service-oriented architecture to replace the priority principle of network efficiency in the Internet to meet requirements of the industrial Internet and smart cities,such as high reliability and low latency.On the other hand,in order to adapt to the uncertainty of future business,5G features the openness of services and the Internet protocols,different from the closeness of traditional telecommunication networks.Although 5G tries to have the advantages of both the Internet and telecommunication network,its realization still faces many challenges.In this paper,ten major issues concerning 5G networking and service offering are discussed.展开更多
Using Nevanlinna theory of the value distribution of meromorphic functions, we investigate the problem of the existence of meromorphic solutions of some types of complex differential-difference equations and some prop...Using Nevanlinna theory of the value distribution of meromorphic functions, we investigate the problem of the existence of meromorphic solutions of some types of complex differential-difference equations and some properties of meromorphic solutions, and we ob- tain some results, which are the improvements and extensions of some results in references. Examples show that our results are precise.展开更多
The annual, interannual and inter-decadal variability of convection intensity of South China Sea (SCS) summer monsoon and air-sea temperature difference in the tropical ocean is analyzed, and their relationship is dis...The annual, interannual and inter-decadal variability of convection intensity of South China Sea (SCS) summer monsoon and air-sea temperature difference in the tropical ocean is analyzed, and their relationship is discussed using two data sets of 48-a SODA (simple ocean data assimilation) and NCEP/NCAR. Analyses show that in wintertime Indian Ocean (WIO), springtime central tropical Pacific (SCTP) and summertime South China Sea-West Pacific (SSCSWP), air-sea temperature difference is significantly associated with the convection intensity of South China Sea summer monsoon. Correlation of the inter-decadal time scale (above 10 a) is higher and more stable. There is inter-decadal variability of correlation in scales less than 10 a and it is related with the air-sea temperature difference itself for corresponding waters. The inter-decadal variability of the convection intensity during the South China Sea summer monsoon is closely related to the inter-decadal variability of the general circulation of the atmosphere. Since the late period of the 1970s, in the lower troposphere, the cross-equatorial flow from the Southern Hemisphere has intensified. At the upper troposphere layer, the South Asian high and cross-equatorial flow from the Northern Hemisphere has intensified at the same time. Then the monsoon cell has also strengthened and resulted in the reinforcing of the convection of South China Sea summer monsoon.展开更多
A new boundary extension technique based on the Lagrange interpolat- ing polynomial is proposed and used to solve the function approximation defined on an interval by a series of scaling Coiflet functions, where the c...A new boundary extension technique based on the Lagrange interpolat- ing polynomial is proposed and used to solve the function approximation defined on an interval by a series of scaling Coiflet functions, where the coefficients are used as the single-point samplings. The obtained approximation formula can exactly represent any polynomials defined on the interval with the order up to one third of the length of the compact support of the adopted Coiflet function. Based on the Galerkin method, a Coifiet-based solution procedure is established for general two-dimensional p^Laplacian equations, following which the equations can be discretized into a concise matrix form. As examples of applications, the proposed modified wavelet Galerkin method is applied to three typical p-Laplacian equations with strong nonlinearity. The numerical results justify the efficiency and accuracy of the method.展开更多
Chou and Chen’s report in the 1970s suggested conformational protein adaptation (CPA) might be influenced by low frequency phonons acting as “a possible information system”. This report proposes the universal force...Chou and Chen’s report in the 1970s suggested conformational protein adaptation (CPA) might be influenced by low frequency phonons acting as “a possible information system”. This report proposes the universal force of electromagnetism initiates the phonon system they cited as it per-turbs paramagnetic/diamagnetic dampers within the protein matrix to produce a quantized low frequency phonon signal series. (http://www.phy.ilstu.edu/~ren/phononsims/page3.html) The signal series is iteratively processed by the protein beta sub-unit, the system, to posi-tion the alpha sub-unit, the outcome, a classic non-linear resonance system resulting in con-formational protein adaptation (CPA). CPA “priming” enables a secondary ATP/redox driven power system to complete cell activity. The evolutionary appearance of these two systems reflects their hierarchy: 1) a low energy phonon driven information control circuit governed by principles of physics that, along with proteins, may have preceded planet earth, and 2), an ATP/redox power completion circuit directed by principles of chemistry that evolved in living systems 1 billion or more years after earth formed.展开更多
This paper reviews recent advances in radar sensor design for low-power healthcare,indoor real-time positioning and other applications of IoT.Various radar front-end architectures and digital processing methods are pr...This paper reviews recent advances in radar sensor design for low-power healthcare,indoor real-time positioning and other applications of IoT.Various radar front-end architectures and digital processing methods are proposed to improve the detection performance including detection accuracy,detection range and power consumption.While many of the reported designs were prototypes for concept verification,several integrated radar systems have been demonstrated with reliable measured results with demo systems.A performance comparison of latest radar chip designs has been provided to show their features of different architectures.With great development of IoT,short-range low-power radar sensors for healthcare and indoor positioning applications will attract more and more research interests in the near future.展开更多
文摘Living-donor liver transplantation has provided a solution to the severe lack of cadaver grafts for the replacement of liver afflicted with end-stage cirrhosis, fulminant disease, or inborn errors of metabolism. Vascular complications remain the most serious complications and a common cause for graft failure after hepatic transplantation. Doppler ultrasound remains the primary radiological imaging modality for the diagnosis of such complications. This article presents a brief review of intra- and post-operative living donor liver transplantation anatomy and a synopsis of the role of ultrasonography and color Doppler in evaluating the graft vascular haemodynamics both during surgery and post-operatively in accurately defining the early vascular complications. Intra-operative ultrasonography of the liver graft provides the surgeon with useful real-time diagnostic and staging information that may result in an alteration in the planned surgical approach and corrections of surgical complications during the procedure of vascular anastomoses. The relevant intraoperative anatomy and the spectrum of normal and abnormal findings are described. Ultrasonography and color Doppler also provides the clinicians and surgeons early post-operative potential developmental complications that may occur during hospital stay. Early detection and thus early problem solving can make the difference between graft survival and failure.
文摘Objectives To investigate the causes, theraputic and preventive methods of com- plications associated with transcatheter occlusion of at- rial septal defect ( ASD) using the Amplatzer septal oc- cluder (ASO) in children. Methods 289 cases un- derwent transcatheter closure of ASD with ASO. Com- plications occurred in 9 cases. The complications in procedure included systemic circulatory systemic air embolism in 2, pulmonary air embolism in 1, pericar- dial tamponade in 1, ASO malposition requiring emer- gency surgical removal in 1, transient atrial extrasysto- les in 1 and sizing balloon rupture in 1 case. 2 cases with postoperative complications were found in the fol- low-up studies. These included perforation of mitral valve and ASO partially dislodged. In this study, 5 children with intraoperative complication received e- mergency therapy including surgical intervention, and others needed only follow-up, as the complications were transient or asymptomatic. Results There were no children death in this study. The 5 cases who re- ceived treatment were completely healing, and the oth- ers with intra - procedure complications were also had no sequela existed. Cases with mitral valve and ASO partially dislodged were still in follow-up studies, as the 2 patients having no symptoms. Conclutions Air embolism were occurred easily in atrial septal defect cases who received ASO therapy. Complications mainly caused by inappropriate operative procedure and some complications needed emergency treatments. Follow-up studies were important to cases with transcatheter oc- clusion therapy.
文摘Nowadays, picture fuzzy set theory is a flourishing field in mathematics with uncertainty by incorporating the concept of positive, negative and neutral membership degrees of an object. A traditional crisp relation represents the satisfaction or the dissatisfaction of relationship, connection or correspondence between the objects of two or more sets. However, there are some problems that can’t be solved through classical relationships, such as the relationship between two objects being vague. In those situations, picture fuzzy relation over picture fuzzy sets is an important and powerful concept which is suitable for describing correspondences between two vague objects. It represents the strength of association of the elements of picture fuzzy sets. It plays an important role in picture fuzzy modeling, inference and control system and also has important applications in relational databases, approximate reasoning, preference modeling, medical diagnosis, etc. In this article, we define picture fuzzy relations over picture fuzzy sets, including some other fundamental definitions with illustrations. The max-min and min-max compositions of picture fuzzy relations are defined in the light of picture fuzzy sets and discussed some properties related to them. The reflexivity, symmetry and transitivity of a picture fuzzy relation are described over a picture fuzzy set. Finally, various properties are explored related to the picture fuzzy relations over a picture fuzzy set.
基金the National Biomass Modeling Program for Continuous Forest Inventory(NBMP-CFI) funded by the State Forestry Administration of China
文摘Because of global climate change, it is necessary to add forest biomass estimation to national forest resource monitoring. The biomass equations developed for forest biomass estimation should be compatible with volume equations. Based on the tree volume and aboveground biomass data of Masson pine (Pinus massoniana Lamb.) in southern China, we constructed one-, two- and three-variable aboveground biomass equations and biomass conversion functions compatible with tree volume equations by using error-in-variable simultaneous equations. The prediction precision of aboveground biomass estimates from one variable equa- tion exceeded 95%. The regressions of aboveground biomass equations were improved slightly when tree height and crown width were used together with diameter on breast height, although the contributions to regressions were statistically insignificant. For the biomass conversion function on one variable, the conversion factor decreased with increasing diameter, but for the conversion function on two variables, the conversion factor increased with increasing diameter but decreased with in- creasing tree height.
基金supported by the National Natural Science Foundation of China(11032009 and 11272236)
文摘Flexible joints are usually used to transfer velocities in robot systems and may lead to delays in motion transformation due to joint flexibility. In this paper, a linkrotor structure connected by a flexible joint or shaft is firstly modeled to be a slow-fast delayed system when moment of inertia of the lightweight link is far less than that of the heavy rotor. To analyze the stability and oscillations of the slowfast system, the geometric singular perturbation method is extended, with both slow and fast manifolds expressed analytically. The stability of the slow manifold is investigated and critical boundaries are obtained to divide the stable and the unstable regions. To study effects of the transformation delay on the stability and oscillations of the link, two quantitatively different driving forces derived from the negative feedback of the link are considered. The results show that one of these two typical driving forces may drive the link to exhibit a stable state and the other kind of driving force may induce a relaxation oscillation for a very small delay. However, the link loses stability and undergoes regular periodic and bursting oscillation when the transformation delay is large. Basically, a very small delay does not affect the stability of the slow manifold but a large delay affects substantially.
基金Project supported by the National Natural Science Foundation of China (No. 19902006).
文摘Two constraint violation stabilization methods are presented to solve the Euler Lagrange equations of motion of a multibody system with nonholonomic constraints. Compared to the previous works, the newly devised methods can deal with more complicated problems such as those with nonholonomic constraints or redundant constraints, and save the computation time. Finally a numerical simulation of a multibody system is conducted by using the methods given in this paper.
基金Supported by The Wenzhou Municipal Science and Technology Commission Major Projects Funds,No.20090006
文摘AIM: To assess the value of plasma melatonin in pre-dicting acute pancreatitis when combined with the acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and bedside index for severity in acute pancreatitis (BISAP) scoring systems. METHODS: APACHEⅡ and BISAP scores were calculated for 55 patients with acute physiology (AP) in the first 24 h of admission to the hospital. Additionally, morning (6:00 AM) serum melatonin concentrations were measured on the first day after admission. According to the diagnosis and treatment guidelines for acute pancreatitis in China, 42 patients suffered mild AP (MAP). The other 13 patients developed severe AP (SAP). A total of 45 healthy volunteers were used in this study as controls. The ability of melatonin and the APACHEⅡ and BISAP scoring systems to predict SAP was evaluated using a receiver operating characteristic (ROC) curve. The optimal melatonin cutoff concentration for SAP patients, based on the ROC curve, was used to classify the patients into either a high concen-tration group (34 cases) or a low concentration group (21 cases). Differences in the incidence of high scores, according to the APACHEⅡ and BISAP scoring sys- tems, were compared between the two groups. RESULTS: The MAP patients had increased melatonin levels compared to the SAP (38.34 ng/L vs 26.77 ng/L) (P = 0.021) and control patients (38.34 ng/L vs 30.73 ng/L) (P = 0.003). There was no significant difference inmelatoninconcentrations between the SAP group and the control group. The accuracy of determining SAP based on the melatonin level, the APACHEⅡ score and the BISAP score was 0.758, 0.872, and 0.906, respectively, according to the ROC curve. A melatonin concentration ≤ 28.74 ng/L was associated with an increased risk of developing SAP. The incidence of high scores (≥ 3) using the BISAP system was significantly higher in patients with low melatonin concentration (≤ 28.74 ng/L) compared to patients with high melatonin concentration (> 28.74 ng/L) (42.9% vs 14.7%, P = 0.02). The incidence of high APACHEⅡ scores (≥ 10) between the two groups was not significantly different. CONCLUSION: The melatonin concentration is closely related to the severity of AP and the BISAP score. Therefore, we can evaluate the severity of disease by measuring the levels of serum melatonin.
文摘Abstract Problems in agricultural science and technology service system were ana- lyzed, such as system problem, investment and worker quality, and based on this countermeasures were proposed, so as to promote the development of modern agri- culture and construction of new countryside.
文摘The accuracy of numerical simulations and many other material design calculations, such as the rolling force, rollingtorque, etc., depends on the description of stress-strain relationship of the deformed materials. One common methodof describing the stress-strain relationship is using constitutive equations, with the unknown parameters fitted byexperimental data obtained via plane strain compression (PSC). Due to the highly nonlinear behaviour of the constitutive equations and the noise included in the PSC data, determination of the model parameters is difficult. Inthis paper, genetic algorithms were exploited to optimise parameters for the constitutive equations based on thePSC data. The original PSC data were processed to generate the stress-strain data, and data pre-processing wascarried out to remove the noise contained in the original PSC data. Several genetic optimisation schemes have beeninvestigated, with different coding schemes and different genetic operators for selection, crossover and mutation.It was found that the real value coded genetic algorithms converged much faster and were more efficient for theparameter optimisation problem.
基金supported by the National Natural Science Foundation of China under Grant No. 61403068, No. 61232016, No. U1405254 and No. 61501100Fundamental Research Funds for the Central Universities of China under Grant No. N130323002 and No. N130323004+3 种基金Natural Science Foundation of Hebei Province under Grant No. F2015501097 and No. F2016501080Scientific Research Fund of Hebei Provincial Education Department under Grant No. Z2014078the PAPD fundNEUQ internal funding under Grant No. XNB201509 and XNB201510
文摘The problem of mobile localization for wireless sensor network has attracted considerable attention in recent years. The localization accuracy will drastically grade in non-line of sight(NLOS) conditions. In this paper, we propose a mobile localization strategy based on Kalman filter. The key technologies for the proposed method are the NLOS identification and mitigation. The proposed method does not need the prior knowledge of the NLOS error and it is independent of the physical measurement ways. Simulation results show that the proposed method owns the higher localization accuracy when compared with other methods.
文摘Rectal cancers extending through the rectal wall, or involving locoregional lymph nodes (T3/4 or N1/2), have been more difficult to cure. The confines of the bony pelvis and the necessity of preserving the autonomic nerves makes surgical extirpation challenging, which accounts for the high rates of local and distant relapse in this setting. Combined multimodality treatment for rectal cancer stage Ⅱ and Ⅲ was recommended from National Institute of Health consensus. Neoadjuvant chemoradiation using fluoropyrimidine-based regimen prior to surgical resection has emerged as the standard of care in the United States. Optimal time of surgery after neoadjuvant treatment remained unclear and prospective randomized controlled trial is ongoing. Traditionally, 6-8 wk waiting period was commonly used. The accuracy of studies attempting to determine tumor complete response remains problematic. Currently, surgery remains the standard of care for rectal cancer patients following neoadjuvant chemoradiation, where-as observational management is still investigational. In this article, we outline trends and controversies associated with optimal pre-treatment staging, neoadjuvant therapies, surgery, and adjuvant therapy.
文摘As a part of INDEPTH 3/GEODEPTH geological surface investigations were carried out during two field campaigns in 1998 and 1999. The working area covers a roughly N\|S (30~36°N) tren ding, 200km wide belt through the Lhasa Terrane and Qiangtang Terrane at a longitude of 88~90°E. Field geology was focused on geological mapping, structural measurements, and extensive sampling for the purpose of fission track geochronology. Additionally a total number of 742 orientated palaeomagnetic samples were drilled at 73 sites. Most of the samples were taken in fine\|grained sediments of Cretaceous, Eocene, and Neogene age. Five sites were drilled in acid to intermediate volcanics.A first sequence of measurements has been applied on a set of specimen. Most of the chosen formations (>80%) have acquired stable remanences which are carried by hematite and magnetite. As an example for the characteristic demagnetising behaviour of fine\|grained probable Cretaceous sandstones see Fig.1a. The unblocking temperature of 650℃ allows to identify hematite as remanence carrier.. Although single sites show well\|defined mean directions (e.g. site 76B: α 95 =3 8; k =185 8) the distribution among several site means of one formation could scatter (Fig.1b). It has to be checked carefully if rotations of single crustal elements are responsible for this effect. There is evidence to assume the detected characteristic remanences to be primary—further analysis including fold tests will be performed after the data set has increased.
文摘In this paper, we establish travelling wave solutions for some nonlinear evolution equations. The first integral method is used to construct the travelling wave solutions of the modified Benjamin-Bona-Mahony and the coupled Klein-Gordon equations. The obtained results include periodic and solitary wave solutions. The first integral method presents a wider applicability to handling nonlinear wave equations.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11374217,11135012,and 11375262)the Joint Fund of the National Natural Science Foundation of Chinathe China Academy of Engineering Physics(Grant No.11176020)
文摘Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen(CO_(2~–)N_2) mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic(QMD) simulations based on density functional theory including dispersion corrections(DFT-D). We present equilibrium properties of liquid mixture for 112 separate density and temperature points, by selecting densities ranging from ρ = 1.80 g/cm^3 to 3.40 g/cm^3 and temperatures from T = 500 K to 8000 K. In the range of our study, the liquid CO_(2~–)N_2 mixture undergoes a continuous transition from molecular to atomic fluid state and liquid polymerization inferred from pair correlation functions(PCFs)and the distribution of various molecular components. The insulator–metal transition is demonstrated by means of the electronic density of states(DOS).
文摘5G takes the concept of service-oriented architecture to replace the priority principle of network efficiency in the Internet to meet requirements of the industrial Internet and smart cities,such as high reliability and low latency.On the other hand,in order to adapt to the uncertainty of future business,5G features the openness of services and the Internet protocols,different from the closeness of traditional telecommunication networks.Although 5G tries to have the advantages of both the Internet and telecommunication network,its realization still faces many challenges.In this paper,ten major issues concerning 5G networking and service offering are discussed.
基金supported by the National Natural Science Foundation of China(11171013)supported by the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(16XNH117)
文摘Using Nevanlinna theory of the value distribution of meromorphic functions, we investigate the problem of the existence of meromorphic solutions of some types of complex differential-difference equations and some properties of meromorphic solutions, and we ob- tain some results, which are the improvements and extensions of some results in references. Examples show that our results are precise.
基金This study was supported by the project of the National Natural Science Foundation of China"Response of inter-decadal variability of South China Sea summer monsoon to the whole globe variability”under contract number 9021l010“Interannual to interdecadal variability in circulation in the tropical Pa-cific Ocean”under contract number 40136010.
文摘The annual, interannual and inter-decadal variability of convection intensity of South China Sea (SCS) summer monsoon and air-sea temperature difference in the tropical ocean is analyzed, and their relationship is discussed using two data sets of 48-a SODA (simple ocean data assimilation) and NCEP/NCAR. Analyses show that in wintertime Indian Ocean (WIO), springtime central tropical Pacific (SCTP) and summertime South China Sea-West Pacific (SSCSWP), air-sea temperature difference is significantly associated with the convection intensity of South China Sea summer monsoon. Correlation of the inter-decadal time scale (above 10 a) is higher and more stable. There is inter-decadal variability of correlation in scales less than 10 a and it is related with the air-sea temperature difference itself for corresponding waters. The inter-decadal variability of the convection intensity during the South China Sea summer monsoon is closely related to the inter-decadal variability of the general circulation of the atmosphere. Since the late period of the 1970s, in the lower troposphere, the cross-equatorial flow from the Southern Hemisphere has intensified. At the upper troposphere layer, the South Asian high and cross-equatorial flow from the Northern Hemisphere has intensified at the same time. Then the monsoon cell has also strengthened and resulted in the reinforcing of the convection of South China Sea summer monsoon.
基金supported by the National Natural Science Foundation of China(Nos.11472119 and11421062)
文摘A new boundary extension technique based on the Lagrange interpolat- ing polynomial is proposed and used to solve the function approximation defined on an interval by a series of scaling Coiflet functions, where the coefficients are used as the single-point samplings. The obtained approximation formula can exactly represent any polynomials defined on the interval with the order up to one third of the length of the compact support of the adopted Coiflet function. Based on the Galerkin method, a Coifiet-based solution procedure is established for general two-dimensional p^Laplacian equations, following which the equations can be discretized into a concise matrix form. As examples of applications, the proposed modified wavelet Galerkin method is applied to three typical p-Laplacian equations with strong nonlinearity. The numerical results justify the efficiency and accuracy of the method.
文摘Chou and Chen’s report in the 1970s suggested conformational protein adaptation (CPA) might be influenced by low frequency phonons acting as “a possible information system”. This report proposes the universal force of electromagnetism initiates the phonon system they cited as it per-turbs paramagnetic/diamagnetic dampers within the protein matrix to produce a quantized low frequency phonon signal series. (http://www.phy.ilstu.edu/~ren/phononsims/page3.html) The signal series is iteratively processed by the protein beta sub-unit, the system, to posi-tion the alpha sub-unit, the outcome, a classic non-linear resonance system resulting in con-formational protein adaptation (CPA). CPA “priming” enables a secondary ATP/redox driven power system to complete cell activity. The evolutionary appearance of these two systems reflects their hierarchy: 1) a low energy phonon driven information control circuit governed by principles of physics that, along with proteins, may have preceded planet earth, and 2), an ATP/redox power completion circuit directed by principles of chemistry that evolved in living systems 1 billion or more years after earth formed.
文摘This paper reviews recent advances in radar sensor design for low-power healthcare,indoor real-time positioning and other applications of IoT.Various radar front-end architectures and digital processing methods are proposed to improve the detection performance including detection accuracy,detection range and power consumption.While many of the reported designs were prototypes for concept verification,several integrated radar systems have been demonstrated with reliable measured results with demo systems.A performance comparison of latest radar chip designs has been provided to show their features of different architectures.With great development of IoT,short-range low-power radar sensors for healthcare and indoor positioning applications will attract more and more research interests in the near future.