目的从肠道菌群角度分析优化溃结方治疗溃疡性结肠炎(UC)的基本原理。方法采用三硝基苯磺酸(TNBS)/乙醇二次致炎法结合束缚法制备UC大鼠模型。将24只SD大鼠随机分为正常组、模型组、优化溃结方组、柳氮磺胺吡啶组,每组6只。分析4组大鼠...目的从肠道菌群角度分析优化溃结方治疗溃疡性结肠炎(UC)的基本原理。方法采用三硝基苯磺酸(TNBS)/乙醇二次致炎法结合束缚法制备UC大鼠模型。将24只SD大鼠随机分为正常组、模型组、优化溃结方组、柳氮磺胺吡啶组,每组6只。分析4组大鼠治疗前后结肠炎疾病活动指数(DAI),粪便标本菌群的变化。结果与模型组比较,优化溃结方组、柳氮磺胺吡啶组DAI均差异有显著性(P<0.05)。柳氮磺胺吡啶组与优化溃结方组DAI评分比较,无差异(P>0.05)。正常组与模型组存在显著差异的菌属,排名前9位的属水平OTU分别为粪杆菌(Faecalibacterium)、经黏液真杆菌属(Blautia)、狭义梭菌属1(Clostridium sensu stricto 1)、异杆菌属(Allobaculum)、拟杆菌(Bacteroides)、Ruminococcaceae.UCG.013、苏黎世杆菌属(Turicibacter)、乳酸菌(Lactobacillus)、罗姆布茨菌(Romboutsia)。给予优化溃结方治疗后,厚壁菌门、芽孢杆菌纲、乳杆菌目、乳杆菌科、双歧杆菌科、格氏乳杆菌种、鼠乳杆菌种、乳酸菌属相对丰度显著增加(P<0.01);拟杆菌门、变形菌门、梭状芽孢杆菌纲、拟杆菌纲、丹毒丝菌纲、γ变形菌纲、梭菌目、丹毒丝菌、拟杆菌属、Turicibacter、狭义梭菌属1、Ruminococcaceae UCG-013相对丰度显著减少(P<0.01)。优化溃结方组治疗后罗姆布茨菌属、异杆菌属、苏黎世杆菌属多于柳氮磺胺吡啶阳性药组。结论优化溃结方通过增加UC气滞血瘀模型SD大鼠肠道有益菌、减少有害菌的相对丰度,改变肠道细菌数量,降低DAI,降低肠道炎性反应,从而治疗疾病。展开更多
The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructi...The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control theory.The vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration control.The paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering applications.The load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of bridges.The vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element method.Using the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency range.The noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.展开更多
s:A divide- by- 12 8/ 12 9or6 4/ 6 5 dual- modulus prescaler based on new optimized structure and dynam ic circuit technique im plem ented in 0 .2 5 μm CMOS digital technology is described.New optimized structure re...s:A divide- by- 12 8/ 12 9or6 4/ 6 5 dual- modulus prescaler based on new optimized structure and dynam ic circuit technique im plem ented in 0 .2 5 μm CMOS digital technology is described.New optimized structure reduces the propagation delay and has higher operating speed.Based on this structure,an im proved D- flip- flop(DFF) using dynam ic circuit technique is proposed.A prototype is fabricated and the measured results show that this prescaler works well in gigahertz frequency range and consumes only35 m W(including three power- hungry output buffers) when the input frequency is2 .5 GHz and the power supply voltage is2 .5 V.Due to its excellent perform ance,the prescaler could be applied to many RF system s.展开更多
The optimum models of harvesting yield and net profits of large diameter trees for broadleaved forest were developed, of which include matrix growth sub-model, harvesting cost and wood price sub-models, based on the d...The optimum models of harvesting yield and net profits of large diameter trees for broadleaved forest were developed, of which include matrix growth sub-model, harvesting cost and wood price sub-models, based on the data from Hongshi Forestry Bureau, in Changbai Mountain region, Jilin Province, China. The data were measured in 232 permanent sample plots. With the data of permanent sample plots, the parameters of transition probability and ingrowth models were estimated, and some models were compared and partly modified. During the simulation of stand structure, four factors such as largest diameter residual tree （LDT）, the ratio of the number of trees in a given diameter class to those in the next larger diameter class （q）, residual basal area （RBA） and selective cutting cycle （C） were considered. The simulation results showed that the optimum stand structure parameters for large diameter trees are as follows： q is 1.2, LDT is 46cm, RBA is larger than 26 m^2 and selective cutting cycle time （C） is between 10 and 20 years.展开更多
Build-up panels for the commercial aircraft fuselage subjected to the axial compression load are studied by both experimental and theoretical methods.An integral panel is designed with the same overall size and weight...Build-up panels for the commercial aircraft fuselage subjected to the axial compression load are studied by both experimental and theoretical methods.An integral panel is designed with the same overall size and weight as the build-up structure,and finite element models（FEMs）of these two panels are established.Experimental results of build-up panels agree well with the FEM results with the nonliearity and the large deformation,so FEMs are validated.FEM calculation results of these two panels indicate that the failure mode of the integral panel is different from that of the build-up panel,and the failure load increases by 18.4% up to post-buckling.Furthermore,the integral structure is optimized by using the multi-island genetic algorithm and the sequential quadratic programming.Compared with the initial design,the optimal mass is reduced by 8.7% and the strength is unchanged.展开更多
Aimed at studying normali zed radial basis function network (NRBFN), this paper introduces the subtractiv e clustering based on a mountain function to construct the initial structure of NR BFN, adopts singular value ...Aimed at studying normali zed radial basis function network (NRBFN), this paper introduces the subtractiv e clustering based on a mountain function to construct the initial structure of NR BFN, adopts singular value decomposition (SVD) to analyze the relationship betwe en neural nodes of the hidden layer and singular values, cumulative contribution ratio, index vector, and optimizes the structure of NRBFN. Finally, simulation and performance comparison show that the algorithm is feasible and effective.展开更多
Aim To introduce a new method of adaptive shape optimization (ASOP) based on three-dimensional structure boundary strength and optimize an engine bearing cap with the method. Methods Using the normal substance's p...Aim To introduce a new method of adaptive shape optimization (ASOP) based on three-dimensional structure boundary strength and optimize an engine bearing cap with the method. Methods Using the normal substance's property of thermal expansion and cooling shrinkage,the load which is proportional to the difference between the nodes' stress and their respective objective stress were applied to the corresponding variable nodes on the boundary.The thermal load made the nodes whose stress is greater than their objective stress expand along the boundary's normal direction and the nodes whose stress is less than objec- tive stress shrink in the opposite direction , This process would repeat until the stress on the boundary nodes was converge to the objective stress. Results The satisfied results have been obtained when optimizing an engine bearing cap.The mass of the bearing cap is reduced to 55 percent of the total. Conclusion ASOP is an efficient,practical and reliable method which is suitable for optimizing the shape of the continuous structures.展开更多
The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two ...The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting （SLM） technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.展开更多
文摘目的从肠道菌群角度分析优化溃结方治疗溃疡性结肠炎(UC)的基本原理。方法采用三硝基苯磺酸(TNBS)/乙醇二次致炎法结合束缚法制备UC大鼠模型。将24只SD大鼠随机分为正常组、模型组、优化溃结方组、柳氮磺胺吡啶组,每组6只。分析4组大鼠治疗前后结肠炎疾病活动指数(DAI),粪便标本菌群的变化。结果与模型组比较,优化溃结方组、柳氮磺胺吡啶组DAI均差异有显著性(P<0.05)。柳氮磺胺吡啶组与优化溃结方组DAI评分比较,无差异(P>0.05)。正常组与模型组存在显著差异的菌属,排名前9位的属水平OTU分别为粪杆菌(Faecalibacterium)、经黏液真杆菌属(Blautia)、狭义梭菌属1(Clostridium sensu stricto 1)、异杆菌属(Allobaculum)、拟杆菌(Bacteroides)、Ruminococcaceae.UCG.013、苏黎世杆菌属(Turicibacter)、乳酸菌(Lactobacillus)、罗姆布茨菌(Romboutsia)。给予优化溃结方治疗后,厚壁菌门、芽孢杆菌纲、乳杆菌目、乳杆菌科、双歧杆菌科、格氏乳杆菌种、鼠乳杆菌种、乳酸菌属相对丰度显著增加(P<0.01);拟杆菌门、变形菌门、梭状芽孢杆菌纲、拟杆菌纲、丹毒丝菌纲、γ变形菌纲、梭菌目、丹毒丝菌、拟杆菌属、Turicibacter、狭义梭菌属1、Ruminococcaceae UCG-013相对丰度显著减少(P<0.01)。优化溃结方组治疗后罗姆布茨菌属、异杆菌属、苏黎世杆菌属多于柳氮磺胺吡啶阳性药组。结论优化溃结方通过增加UC气滞血瘀模型SD大鼠肠道有益菌、减少有害菌的相对丰度,改变肠道细菌数量,降低DAI,降低肠道炎性反应,从而治疗疾病。
基金Project(51978585)supported by the National Natural Science Foundation,ChinaProject(2022YFB2603404)supported by the National Key Research and Development Program,China+1 种基金Project(U1734207)supported by the High-speed Rail Joint Fund Key Projects of Basic Research,ChinaProject(2023NSFSC1975)supported by the Sichuan Nature and Science Foundation Innovation Research Group Project,China。
文摘The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control theory.The vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration control.The paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering applications.The load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of bridges.The vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element method.Using the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency range.The noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.
文摘s:A divide- by- 12 8/ 12 9or6 4/ 6 5 dual- modulus prescaler based on new optimized structure and dynam ic circuit technique im plem ented in 0 .2 5 μm CMOS digital technology is described.New optimized structure reduces the propagation delay and has higher operating speed.Based on this structure,an im proved D- flip- flop(DFF) using dynam ic circuit technique is proposed.A prototype is fabricated and the measured results show that this prescaler works well in gigahertz frequency range and consumes only35 m W(including three power- hungry output buffers) when the input frequency is2 .5 GHz and the power supply voltage is2 .5 V.Due to its excellent perform ance,the prescaler could be applied to many RF system s.
基金This paper was supported by National Strategy Key Project, Research and Paradigm on Ecological Harvesting and Regeneration Tech-nique for Northeast Natural Forest (2001BA510B07-02)
文摘The optimum models of harvesting yield and net profits of large diameter trees for broadleaved forest were developed, of which include matrix growth sub-model, harvesting cost and wood price sub-models, based on the data from Hongshi Forestry Bureau, in Changbai Mountain region, Jilin Province, China. The data were measured in 232 permanent sample plots. With the data of permanent sample plots, the parameters of transition probability and ingrowth models were estimated, and some models were compared and partly modified. During the simulation of stand structure, four factors such as largest diameter residual tree （LDT）, the ratio of the number of trees in a given diameter class to those in the next larger diameter class （q）, residual basal area （RBA） and selective cutting cycle （C） were considered. The simulation results showed that the optimum stand structure parameters for large diameter trees are as follows： q is 1.2, LDT is 46cm, RBA is larger than 26 m^2 and selective cutting cycle time （C） is between 10 and 20 years.
文摘Build-up panels for the commercial aircraft fuselage subjected to the axial compression load are studied by both experimental and theoretical methods.An integral panel is designed with the same overall size and weight as the build-up structure,and finite element models（FEMs）of these two panels are established.Experimental results of build-up panels agree well with the FEM results with the nonliearity and the large deformation,so FEMs are validated.FEM calculation results of these two panels indicate that the failure mode of the integral panel is different from that of the build-up panel,and the failure load increases by 18.4% up to post-buckling.Furthermore,the integral structure is optimized by using the multi-island genetic algorithm and the sequential quadratic programming.Compared with the initial design,the optimal mass is reduced by 8.7% and the strength is unchanged.
文摘Aimed at studying normali zed radial basis function network (NRBFN), this paper introduces the subtractiv e clustering based on a mountain function to construct the initial structure of NR BFN, adopts singular value decomposition (SVD) to analyze the relationship betwe en neural nodes of the hidden layer and singular values, cumulative contribution ratio, index vector, and optimizes the structure of NRBFN. Finally, simulation and performance comparison show that the algorithm is feasible and effective.
文摘Aim To introduce a new method of adaptive shape optimization (ASOP) based on three-dimensional structure boundary strength and optimize an engine bearing cap with the method. Methods Using the normal substance's property of thermal expansion and cooling shrinkage,the load which is proportional to the difference between the nodes' stress and their respective objective stress were applied to the corresponding variable nodes on the boundary.The thermal load made the nodes whose stress is greater than their objective stress expand along the boundary's normal direction and the nodes whose stress is less than objec- tive stress shrink in the opposite direction , This process would repeat until the stress on the boundary nodes was converge to the objective stress. Results The satisfied results have been obtained when optimizing an engine bearing cap.The mass of the bearing cap is reduced to 55 percent of the total. Conclusion ASOP is an efficient,practical and reliable method which is suitable for optimizing the shape of the continuous structures.
基金Project (51275179) supported by the National Natural Science Foundation of ChinaProject (2010A090200072) supported by Industry,University and Research Institute Combination of Ministry of Education, Ministry of Science and Technology and Guangdong Province,China+1 种基金Project (2012M511797) supported by China Postdoctoral Science FoundationProject (2012ZB0014) supported by FundamentalResearch Funds for the Central Universities of China
文摘The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting （SLM） technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.
