根据地面钻井液分析地层含烃量的技术由来已久。文中认为,此类分析技术在缺乏明确的规范和严格的测量步骤情况下,测量结果误差较大,难以据此准确解释地层含烃量。1994年获美国专利的联机气体参照法(On—line Gas Referencing)可使气测...根据地面钻井液分析地层含烃量的技术由来已久。文中认为,此类分析技术在缺乏明确的规范和严格的测量步骤情况下,测量结果误差较大,难以据此准确解释地层含烃量。1994年获美国专利的联机气体参照法(On—line Gas Referencing)可使气测参数的精度和价值大为提高,并简化解释工作。其要点是在地面的钻井液管线中(泵入口)加入非固有气体(如乙炔)作为“参照气”,并连续维持一定的浓度。工作时运用常规的脱气器同时从钻井液中提取参照气和天然气,并同时用标准的气相色谱仪测量。通过已知的参照气浓度使每一种所测量的地层气归一化,进而推导钻井液中每一种所测量的地层气的浓度。其数据质量及质量控制是通过对参照气连续测试以验证测量系统稳定特性来保证的。其它重要特性包括迟到时间的验证,可通过瞬时增加参照气浓度的方法来校正。当钻井液性能变化时将影响脱气器的效率,此时参照气将出现相应的响应。因此,应用此方法用户可得到可靠的、定量化的气显示数据,进而增强决策能力。展开更多
This work is aimed at investigating the online scheduling problem on two parallel and identical machines with a new feature that service requests from various customers are entitled to many different grade of service ...This work is aimed at investigating the online scheduling problem on two parallel and identical machines with a new feature that service requests from various customers are entitled to many different grade of service (GoS) levels, so each job and machine are labelled with the GoS levels, and each job can be processed by a particular machine only when its GoS level is no less than that of the machine. The goal is to minimize the makespan. For non-preemptive version, we propose an optimal online al-gorithm with competitive ratio 5/3. For preemptive version, we propose an optimal online algorithm with competitive ratio 3/2.展开更多
Permeability is a vital property of rock mass, which is highly affected by tectonic stress and human engineering activities. A comprehensive monitoring of pore pressure and flow rate distributions inside the rock mass...Permeability is a vital property of rock mass, which is highly affected by tectonic stress and human engineering activities. A comprehensive monitoring of pore pressure and flow rate distributions inside the rock mass is very important to elucidate the permeability evolution mechanisms, which is difficult to realize in laboratory, but easy to be achieved in numerical simulations. Therefore, the particle flow code （PFC）, a discrete element method, is used to simulate permeability behaviors of rock materials in this study. Owe to the limitation of the existed solid-fluid coupling algorithm in PFC, an improved flow-coupling algorithm is presented to better reflect the preferential flow in rock fractures. The comparative analysis is conducted between original and improved algorithm when simulating rock permeability evolution during triaxial compression, showing that the improved algorithm can better describe the experimental phenomenon. Furthermore, the evolution of pore pressure and flow rate distribution during the flow process are analyzed by using the improved algorithm. It is concluded that during the steady flow process in the fractured specimen, the pore pressure and flow rate both prefer transmitting through the fractures rather than rock matrix. Based on the results, fractures are divided into the following three types： I） fractures link to both the inlet and outlet, II） fractures only link to the inlet, and III） fractures only link to the outlet. The type I fracture is always the preferential propagating path for both the pore pressure and flow rate. For type II fractures, the pore pressure increases and then becomes steady. However, the flow rate increases first and begins to decrease after the flow reaches the stop end of the fracture and finally vanishes. There is no obvious pore pressure or flow rate concentration within type III fractures.展开更多
Parallel manipulator is associated with a set of functions defined by its closure constraints. In this paper, using Lie algebra method, we provide a study on the singularities of parallel manipulators, their relations...Parallel manipulator is associated with a set of functions defined by its closure constraints. In this paper, using Lie algebra method, we provide a study on the singularities of parallel manipulators, their relations with the second order of the closure functions, and the tangent space of the configuration space of the manipulator. The transverse condition criterion is applied to analyze the behavior of the singularities. This gives a downright explication why the 6R paradoxical mechanisms work in their singular configurations, and allows to gain insight on configuration space singularities and to choose the adequate design parameters for the parallel manipulator.展开更多
Objective To explore methods of preventing and reversing rejection after simultaneous pancreas-kidney （SPK） transplantation. Methods Seventeen patients underwent SPK transplantation from September 1999 to September...Objective To explore methods of preventing and reversing rejection after simultaneous pancreas-kidney （SPK） transplantation. Methods Seventeen patients underwent SPK transplantation from September 1999 to September 2003 were reviewed retrospectively. Immunosuppression was achieved by a triple drug regimen consisting of cyclosporine, mycophenolate mofleil （MMF）, and steroids. Three patients were treated with anti-CD3 monoclone antibody （OKT3, 5 mg·d^-1） for induction therapy for a mean period of 5-7 days. One patients received IL-2 receptor antibodies （daclizumab） in a dose of I mg·kg^-1 on the day of transplant and the 5th day posttransplant. One patient was treated with both OKT3 and daclizumab for induction. Results No primary non-functionality of either kidney or pancreas occurred in this series of transplantations. Function of all the kidney grafts recovered within 2 to 4 days after transplantation. The level of serum creatinine was 94 ± 11 μmol/L on the 7th day posttransplant. One patient experienced the accelerated rejection, resulting in the resection of the pancreas and kidney grafts because of the failure of conservative therapy. The incidence of the first rejection episodes at 3 months was 47.1% （8/17）. Only the kidney was involved in 35.3% （6/17）; and both the pancreas and kidney were involved in 11.8% （2/17）. All these patients received a high-dose pulse of methylprednisone （0.5 g·d^-1） for 3 days. OKT3 （0.5 mg·d^-1） was administered for 7-10 days in two patients with both renal and pancreas rejection. All the grafts were successfully rescued. Conclusion Rejection, particularly acute rejection, is the major cause influencing graft function in SPK transplantation. Monitoring renal function and pancreas exocrine secretion, and reasonable application of immunosuppressants play important roles in the diagnosis and treatment of rejection.展开更多
Objective The aim of the study was to determine whether bronchial asthma was associated with increased levels of soluble intercellular adhesion molecule 1(sICAM 1) in serum, which might be ...Objective The aim of the study was to determine whether bronchial asthma was associated with increased levels of soluble intercellular adhesion molecule 1(sICAM 1) in serum, which might be valuble data for the effective therapy of these patients Patients and methods The concentrations of sICAM 1 were determined in sera of healthy donors and asthmatic patients using a sensitive enzyme immunoassay Results The mean(±SD) levels of serum sICAM 1 of 26 asthmatic patients (205±72 0 μg/L)was significantly higher than that of the 30 healthy volunteers (154±63 9 μg/L,P<0 01) There was no much difference between the serum levels in 12 patients suffering from atopic asthma and the levels in 14 patients with nonatopic asthma The serum concentrations of sICAM 1 were higher during asthma attacks than that during remissions in the same patients (P<0 05) Conclusion These results suggest that sICAM 1 may play a certain role in the pathophysiology of bronchial asthma,and might be signals for successful treatment展开更多
We discuss an object from algebraic topology,Hopf invariant,and reinterpret it in terms of the φ-mappingtopological current theory.The main purpose of this paper is to present a new theoretical framework,which can di...We discuss an object from algebraic topology,Hopf invariant,and reinterpret it in terms of the φ-mappingtopological current theory.The main purpose of this paper is to present a new theoretical framework,which can directlygive the relationship between Hopf invariant and the linking numbers of the higher dimensional submanifolds of Euclideanspace R^(2n-1).For the sake of this purpose we introduce a topological tensor current,which can naturally deduce the(n-1)-dimensional topological defect in R^(2n-1) space.If these (n-1)-dimensional topological defects are closed orientedsubmanifolds of R^(2n-1),they are just the (n-1)-dimensional knots.The linking number of these knots is well defined.Using the inner structure of the topological tensor current,the relationship between Hopf invariant and the linkingnumbers of the higher-dimensional knots can be constructed.展开更多
文摘根据地面钻井液分析地层含烃量的技术由来已久。文中认为,此类分析技术在缺乏明确的规范和严格的测量步骤情况下,测量结果误差较大,难以据此准确解释地层含烃量。1994年获美国专利的联机气体参照法(On—line Gas Referencing)可使气测参数的精度和价值大为提高,并简化解释工作。其要点是在地面的钻井液管线中(泵入口)加入非固有气体(如乙炔)作为“参照气”,并连续维持一定的浓度。工作时运用常规的脱气器同时从钻井液中提取参照气和天然气,并同时用标准的气相色谱仪测量。通过已知的参照气浓度使每一种所测量的地层气归一化,进而推导钻井液中每一种所测量的地层气的浓度。其数据质量及质量控制是通过对参照气连续测试以验证测量系统稳定特性来保证的。其它重要特性包括迟到时间的验证,可通过瞬时增加参照气浓度的方法来校正。当钻井液性能变化时将影响脱气器的效率,此时参照气将出现相应的响应。因此,应用此方法用户可得到可靠的、定量化的气显示数据,进而增强决策能力。
基金Project supported by the National Natural Science Foundation of China (No. 10271110) and the Teaching and Research Award Pro-gram for Outstanding Young Teachers in Higher Education, Institu-tions of MOE, China
文摘This work is aimed at investigating the online scheduling problem on two parallel and identical machines with a new feature that service requests from various customers are entitled to many different grade of service (GoS) levels, so each job and machine are labelled with the GoS levels, and each job can be processed by a particular machine only when its GoS level is no less than that of the machine. The goal is to minimize the makespan. For non-preemptive version, we propose an optimal online al-gorithm with competitive ratio 5/3. For preemptive version, we propose an optimal online algorithm with competitive ratio 3/2.
基金Project（BK20150005） supported by the Natural Science Foundation of Jiangsu Province for Distinguished Young Scholars, China Project（2015XKZD05） supported by the Fundamental Research Funds for the Central Universities, China
文摘Permeability is a vital property of rock mass, which is highly affected by tectonic stress and human engineering activities. A comprehensive monitoring of pore pressure and flow rate distributions inside the rock mass is very important to elucidate the permeability evolution mechanisms, which is difficult to realize in laboratory, but easy to be achieved in numerical simulations. Therefore, the particle flow code （PFC）, a discrete element method, is used to simulate permeability behaviors of rock materials in this study. Owe to the limitation of the existed solid-fluid coupling algorithm in PFC, an improved flow-coupling algorithm is presented to better reflect the preferential flow in rock fractures. The comparative analysis is conducted between original and improved algorithm when simulating rock permeability evolution during triaxial compression, showing that the improved algorithm can better describe the experimental phenomenon. Furthermore, the evolution of pore pressure and flow rate distribution during the flow process are analyzed by using the improved algorithm. It is concluded that during the steady flow process in the fractured specimen, the pore pressure and flow rate both prefer transmitting through the fractures rather than rock matrix. Based on the results, fractures are divided into the following three types： I） fractures link to both the inlet and outlet, II） fractures only link to the inlet, and III） fractures only link to the outlet. The type I fracture is always the preferential propagating path for both the pore pressure and flow rate. For type II fractures, the pore pressure increases and then becomes steady. However, the flow rate increases first and begins to decrease after the flow reaches the stop end of the fracture and finally vanishes. There is no obvious pore pressure or flow rate concentration within type III fractures.
基金Supported in part by the Key Project of the National Nature Science Foundation of China (No.60534020)the National Nature Science Foundation of China (No.60474037)the National 863 Plan of China (No.2002AA755026)
文摘Parallel manipulator is associated with a set of functions defined by its closure constraints. In this paper, using Lie algebra method, we provide a study on the singularities of parallel manipulators, their relations with the second order of the closure functions, and the tangent space of the configuration space of the manipulator. The transverse condition criterion is applied to analyze the behavior of the singularities. This gives a downright explication why the 6R paradoxical mechanisms work in their singular configurations, and allows to gain insight on configuration space singularities and to choose the adequate design parameters for the parallel manipulator.
文摘Objective To explore methods of preventing and reversing rejection after simultaneous pancreas-kidney （SPK） transplantation. Methods Seventeen patients underwent SPK transplantation from September 1999 to September 2003 were reviewed retrospectively. Immunosuppression was achieved by a triple drug regimen consisting of cyclosporine, mycophenolate mofleil （MMF）, and steroids. Three patients were treated with anti-CD3 monoclone antibody （OKT3, 5 mg·d^-1） for induction therapy for a mean period of 5-7 days. One patients received IL-2 receptor antibodies （daclizumab） in a dose of I mg·kg^-1 on the day of transplant and the 5th day posttransplant. One patient was treated with both OKT3 and daclizumab for induction. Results No primary non-functionality of either kidney or pancreas occurred in this series of transplantations. Function of all the kidney grafts recovered within 2 to 4 days after transplantation. The level of serum creatinine was 94 ± 11 μmol/L on the 7th day posttransplant. One patient experienced the accelerated rejection, resulting in the resection of the pancreas and kidney grafts because of the failure of conservative therapy. The incidence of the first rejection episodes at 3 months was 47.1% （8/17）. Only the kidney was involved in 35.3% （6/17）; and both the pancreas and kidney were involved in 11.8% （2/17）. All these patients received a high-dose pulse of methylprednisone （0.5 g·d^-1） for 3 days. OKT3 （0.5 mg·d^-1） was administered for 7-10 days in two patients with both renal and pancreas rejection. All the grafts were successfully rescued. Conclusion Rejection, particularly acute rejection, is the major cause influencing graft function in SPK transplantation. Monitoring renal function and pancreas exocrine secretion, and reasonable application of immunosuppressants play important roles in the diagnosis and treatment of rejection.
文摘Objective The aim of the study was to determine whether bronchial asthma was associated with increased levels of soluble intercellular adhesion molecule 1(sICAM 1) in serum, which might be valuble data for the effective therapy of these patients Patients and methods The concentrations of sICAM 1 were determined in sera of healthy donors and asthmatic patients using a sensitive enzyme immunoassay Results The mean(±SD) levels of serum sICAM 1 of 26 asthmatic patients (205±72 0 μg/L)was significantly higher than that of the 30 healthy volunteers (154±63 9 μg/L,P<0 01) There was no much difference between the serum levels in 12 patients suffering from atopic asthma and the levels in 14 patients with nonatopic asthma The serum concentrations of sICAM 1 were higher during asthma attacks than that during remissions in the same patients (P<0 05) Conclusion These results suggest that sICAM 1 may play a certain role in the pathophysiology of bronchial asthma,and might be signals for successful treatment
基金National Natural Science Foundation of China and Cuiying Project of Lanzhou University
文摘We discuss an object from algebraic topology,Hopf invariant,and reinterpret it in terms of the φ-mappingtopological current theory.The main purpose of this paper is to present a new theoretical framework,which can directlygive the relationship between Hopf invariant and the linking numbers of the higher dimensional submanifolds of Euclideanspace R^(2n-1).For the sake of this purpose we introduce a topological tensor current,which can naturally deduce the(n-1)-dimensional topological defect in R^(2n-1) space.If these (n-1)-dimensional topological defects are closed orientedsubmanifolds of R^(2n-1),they are just the (n-1)-dimensional knots.The linking number of these knots is well defined.Using the inner structure of the topological tensor current,the relationship between Hopf invariant and the linkingnumbers of the higher-dimensional knots can be constructed.
