N-ros is one of the transforming genes in human hepatic cancer cells. It has been found that N-ras was overexpressed at the mENA and protein level in hepatoma cells. In order to explore the biological roles of N-ras i...N-ros is one of the transforming genes in human hepatic cancer cells. It has been found that N-ras was overexpressed at the mENA and protein level in hepatoma cells. In order to explore the biological roles of N-ras in human hepatic oaroinogenesis and the potential application in control of cancer cell growth, a pseudotype retrovirus containing antisense sequence of human N-ras was constructed and packaged. A recombinant rebrovirus vector containing antisense or sense sequences of N-ras oDNA was constructed by pZIP-NeoSV(X)1. The pseudotype virus was packaged and rescued by transfeotion and infection in PA317 and ψ2 helper cells. It has been demonstrated that the pseudotype retrovirus containing antisense N-ras sequence did inhibit the growth of human PLC/PEF/5 hepatoma cells accompanied with inhibition of p21 expression, while the retrovirus containing sense sequence had none. The pseudotype virus had no effect on human diploid fibroblasts.展开更多
This paper seeks to identify the minimal restrictions that need to be placed on the naive comprehension principle to avoid inconsistency in set theory. Analysis of the logical antinomies shows that at the root of inco...This paper seeks to identify the minimal restrictions that need to be placed on the naive comprehension principle to avoid inconsistency in set theory. Analysis of the logical antinomies shows that at the root of inconsistency in naive set theory are certain ＂self contradictory＂ predicate functions in extensional set descriptions containing the matrix ＂-（x∈y）＂ （or ＂-（x∈x）＂） rather than ＂size,＂ vicious circularity, or self-reference. A reformed set comprehension system is proposed that excludes extensional set descriptions that conform to the formula, （Vx） （Зy） （x∈y →P （x）） （3u） （u∈y→（u∈y））, from comprehension and otherwise preserves the ontology of na＇fve set theory. This reform avoids the paradoxes by scrutiny of a set＇s description without recourse to type or other constructivist limitations on self-membership and has the most liberal rules for set formation conceivable including self-membership. The intuitive appeal for such an approach is compelling because as a revision of na＇fve set theory, it allows all possible set descriptions that do not lead to inconsistency.展开更多
Severe vibration of underground structures may be induced under blast loads. According to the characteristics of the explosion-induced ground shock wave, a new-type damper, inverse control magneto-rheological（MR） da...Severe vibration of underground structures may be induced under blast loads. According to the characteristics of the explosion-induced ground shock wave, a new-type damper, inverse control magneto-rheological（MR） damper was designed to control the vibration, The high-frequency performance test of the MR damper was carried out on the small shaking table. It is shown that the performance can be modeled by use of the modified Bouc-Wen model, and the Parameters of the model keep stable in the range of 15--50 Hz.展开更多
This paper investigates steady-state and dynamic simulation of an industrial fixed-bed ethylene oxide reactor. A mathematical heterogeneous one-dimensional model is developed for simulation of reactor performance in t...This paper investigates steady-state and dynamic simulation of an industrial fixed-bed ethylene oxide reactor. A mathematical heterogeneous one-dimensional model is developed for simulation of reactor performance in the presence of long term deactivation of silver/a-alumina catalyst. In this paper, steady-state model of the reactor is solved and results of steady state simulation are fed to dynamic simulator as initial condition. When results of dynamic simulation are compared with industrial reactor data, it is found that there were good agreements between simulation results and industrial data. The proposed model is also validated by industrial process data for a period of 1100 operating days.展开更多
Ground motion intensity measure (IM) is an important part in performance-based seismic design. A reasonable and efficient IM can make the prediction of the structural seismic responses more accurate. Therefore, a more...Ground motion intensity measure (IM) is an important part in performance-based seismic design. A reasonable and efficient IM can make the prediction of the structural seismic responses more accurate. Therefore, a more reasonable IM for super high-rise buildings is proposed in this paper. This IM takes into account the significant characteristic that higher-order vibration modes play important roles in the seismic response of super high-rise buildings, as well as the advantages of some existing IMs. The key parameter of the proposed IM is calibrated using a series of time-history analyses. The collapse simulations of two super high-rise buildings are used to discuss the suitability of the proposed IM and some other existing IMs. The results indicate that the proposed IM yields a smaller coefficient of variation for the critical collapse status than other existing IMs and performs well in reflecting the contribution of higher-order vibration modes to the structural response. Hence, the proposed IM is more applicable to seismic design for super high-rise buildings than other IMs.展开更多
文摘N-ros is one of the transforming genes in human hepatic cancer cells. It has been found that N-ras was overexpressed at the mENA and protein level in hepatoma cells. In order to explore the biological roles of N-ras in human hepatic oaroinogenesis and the potential application in control of cancer cell growth, a pseudotype retrovirus containing antisense sequence of human N-ras was constructed and packaged. A recombinant rebrovirus vector containing antisense or sense sequences of N-ras oDNA was constructed by pZIP-NeoSV(X)1. The pseudotype virus was packaged and rescued by transfeotion and infection in PA317 and ψ2 helper cells. It has been demonstrated that the pseudotype retrovirus containing antisense N-ras sequence did inhibit the growth of human PLC/PEF/5 hepatoma cells accompanied with inhibition of p21 expression, while the retrovirus containing sense sequence had none. The pseudotype virus had no effect on human diploid fibroblasts.
文摘This paper seeks to identify the minimal restrictions that need to be placed on the naive comprehension principle to avoid inconsistency in set theory. Analysis of the logical antinomies shows that at the root of inconsistency in naive set theory are certain ＂self contradictory＂ predicate functions in extensional set descriptions containing the matrix ＂-（x∈y）＂ （or ＂-（x∈x）＂） rather than ＂size,＂ vicious circularity, or self-reference. A reformed set comprehension system is proposed that excludes extensional set descriptions that conform to the formula, （Vx） （Зy） （x∈y →P （x）） （3u） （u∈y→（u∈y））, from comprehension and otherwise preserves the ontology of na＇fve set theory. This reform avoids the paradoxes by scrutiny of a set＇s description without recourse to type or other constructivist limitations on self-membership and has the most liberal rules for set formation conceivable including self-membership. The intuitive appeal for such an approach is compelling because as a revision of na＇fve set theory, it allows all possible set descriptions that do not lead to inconsistency.
基金Supported by National Nature Fund and National Civil-Defense Office
文摘Severe vibration of underground structures may be induced under blast loads. According to the characteristics of the explosion-induced ground shock wave, a new-type damper, inverse control magneto-rheological（MR） damper was designed to control the vibration, The high-frequency performance test of the MR damper was carried out on the small shaking table. It is shown that the performance can be modeled by use of the modified Bouc-Wen model, and the Parameters of the model keep stable in the range of 15--50 Hz.
文摘This paper investigates steady-state and dynamic simulation of an industrial fixed-bed ethylene oxide reactor. A mathematical heterogeneous one-dimensional model is developed for simulation of reactor performance in the presence of long term deactivation of silver/a-alumina catalyst. In this paper, steady-state model of the reactor is solved and results of steady state simulation are fed to dynamic simulator as initial condition. When results of dynamic simulation are compared with industrial reactor data, it is found that there were good agreements between simulation results and industrial data. The proposed model is also validated by industrial process data for a period of 1100 operating days.
基金supported by "Twelfth Five-Year" plan major projects supported by National Science and Technology (Grant No.2011BAJ09B01)the National Nature Science Foundation of China (Grant Nos. 51222804, 51261120377)+1 种基金the Tsinghua University Initiative Scientific Research Program (Grant Nos. 2012THZ02-2, 2011THZ03) the Fok Ying Dong Education Foundation (Grant No. 131071)
文摘Ground motion intensity measure (IM) is an important part in performance-based seismic design. A reasonable and efficient IM can make the prediction of the structural seismic responses more accurate. Therefore, a more reasonable IM for super high-rise buildings is proposed in this paper. This IM takes into account the significant characteristic that higher-order vibration modes play important roles in the seismic response of super high-rise buildings, as well as the advantages of some existing IMs. The key parameter of the proposed IM is calibrated using a series of time-history analyses. The collapse simulations of two super high-rise buildings are used to discuss the suitability of the proposed IM and some other existing IMs. The results indicate that the proposed IM yields a smaller coefficient of variation for the critical collapse status than other existing IMs and performs well in reflecting the contribution of higher-order vibration modes to the structural response. Hence, the proposed IM is more applicable to seismic design for super high-rise buildings than other IMs.
