期刊文献+
共找到110篇文章
< 1 2 6 >
每页显示 20 50 100
试析《三体Ⅲ·死神永生》中程心的扁平人物形象
1
作者 雷萌 《今古文创》 2020年第31期9-10,共2页
《三体Ⅲ·死神永生》自面世以来获得了巨大的成功。程心这一人物也受到了广泛的争议。目前,读者对程心的负面评价多于正面评价,却没有学者对程心的人物形象进行深入的分析。本文从科幻文学作品常塑造的扁平人物形象出发,深入分析... 《三体Ⅲ·死神永生》自面世以来获得了巨大的成功。程心这一人物也受到了广泛的争议。目前,读者对程心的负面评价多于正面评价,却没有学者对程心的人物形象进行深入的分析。本文从科幻文学作品常塑造的扁平人物形象出发,深入分析了程心作为扁平人物的形象特征,为程心代表的形象正名,并得出了肯定的评价。同时,也分析出了程心这一扁平人物形象是人类道德与爱的化身,探讨了在宇宙极端黑暗的环境下,程心这一人物形象所折射出的宇宙生存的终极意义。 展开更多
关键词 扁平人物形象 《三体Ⅲ·死神永生》 程心
下载PDF
Isolation of Endophyte and Screening for Antagonistic Bacteria in Solanaceae 被引量:11
2
作者 刘杰凤 韩寒冰 +2 位作者 张进凤 罗添喜 詹加钦 《Agricultural Science & Technology》 CAS 2009年第1期35-38,共4页
[ Objective] The aim of this study was to isolate the endophyte of three solanaceae fruits and vegetables such as tomato, pepper and eggplant, to screen and identify the bacterial wilt antagonistic bacteria. [ Methodl... [ Objective] The aim of this study was to isolate the endophyte of three solanaceae fruits and vegetables such as tomato, pepper and eggplant, to screen and identify the bacterial wilt antagonistic bacteria. [ Methodl According to the lapping liquid culture method, the endophyte of three plants was isolated by the selective medium and purified by the plate streaking method, so the purified enclophyte was screened by the hyphal pieces confront culture method. Furthermore, the screened antagonistic and endophyteic bacteria was identified and classified through culture characteristics of isolates and morphological features of thallus, Gram stain as well as physiological and biochemical reactions. [ Result] Fifty-three endophytic bacteria, fifty-three endophytic fungi and forty-four endophytic actinomycetes were separated from the endophyte of three plants. The screened fourteen endophytic bacteria with strong antagonistic effect on the bacterial wilt were classified to Bacillus, Escherichia, Klebsiella, Agromonas, Erwinia and Curto Bacterium respectively. Especially, Bacillus was the dominant species, which had the strongest antagonistic effect on the bacterial wilt. [ Conclusion] This study provides an effective way for biological control of the bacterial wilt in solanaceae. 展开更多
关键词 ENDOPHYTE ISOLATION SCREENING ANTAGONISM
下载PDF
The Structural Transformation of Nucleolar DNA and Its Arrangement in Nucleolus of Allium cepa Cells
3
作者 陶伟 张立勇 +3 位作者 黄百渠 焦明大 何孟元 郝水 《Acta Botanica Sinica》 CSCD 2001年第1期6-11,共6页
By using the DNA specific cytochemical staining method (NAMA_Ur) and conventional electron microscopic technique, the authors examined the configuration of intranucleolar DNA in Allium cepa L. cells and found that... By using the DNA specific cytochemical staining method (NAMA_Ur) and conventional electron microscopic technique, the authors examined the configuration of intranucleolar DNA in Allium cepa L. cells and found that nucleolar DNA within the fibrillar center (FC) underwent a structural transformation process from condensed to extended state. The authors' observations also displayed a continuous arrangement process of nucleolar DNA, i.e., the extranucleolar DNA entered FC through the nucleolar organizer region (NOR) channel, then extended to the periphery of FC or to the border between FC and dense fibrillar component (DFC), and distributed along the periphery of FC. Thence, by passing through the NOR channel between FCs, the nucleolar DNA continued to transfer to other FCs and arranged in the same above_mentioned forms. 展开更多
关键词 Allium cepa NUCLEOLUS arrangement of nucleolar DNA fibrillar centers
下载PDF
Prediction of compressive strength of cement mortars with fly ash and activated coal gangue 被引量:5
4
作者 周双喜 陈益民 张文生 《Journal of Southeast University(English Edition)》 EI CAS 2006年第4期549-552,共4页
The pozzolanic activity of coal gangue, which is calcining at 500 to 1 000 ℃, differs distinctly. The simplex-centroid design with upper and lower bounds of component proportion is adopted to study the compressive st... The pozzolanic activity of coal gangue, which is calcining at 500 to 1 000 ℃, differs distinctly. The simplex-centroid design with upper and lower bounds of component proportion is adopted to study the compressive strength of mortars made with ternary blends of cement, activated coal gangue and fly ash. Based on the results of a minimum of seven design points, three special cubic polynomial models are used to establish the strength predicating equations at different ages for mortars. Five experimental checkpoints were also designed to verify the precision of the equations. The most frequent errors of the predicted values are within 3%. A simple and practical way is provided for determining the optimal proportion of two admixtures when they are used in concrete. 展开更多
关键词 thermal activated coal gangue simplex-centroid design predicating equation compressive strength
下载PDF
Exercise and children's cognition:The role of exercise characteristics and a place for metacognition 被引量:12
5
作者 Phillip D.Tomporowski Bryan Mc Cullick +1 位作者 Daniel M.Pendleton Caterina Pesce 《Journal of Sport and Health Science》 SCIE 2015年第1期47-55,共9页
Definitive conclusions concerning the impact of exercise interventions on children's mental functioning are difficult to ascertain because of procedural differences among studies. A narrative review of studies was co... Definitive conclusions concerning the impact of exercise interventions on children's mental functioning are difficult to ascertain because of procedural differences among studies. A narrative review of studies was conducted to evaluate the role of two types of exercise interventions on children's cognition. Acute and chronic exercise interventions were classified as quantitative or qualitative on the basis of manipulations of task complexity and, by inference, mental engagement. Both types of interventions enhance aspects of children's cognition; however, their effects on metacognitive processes are unknown. The role of metacognitive processes and their regulation of children's behavior and academic performance are highlighted. 展开更多
关键词 Academic achievement Child development Executive function Intelligence Memory Mental engagement
下载PDF
Design and Experimental Analyses of Small-flow High-head Centrifugal-vortex Pump for Gas-Liquid Two-phase Mixture 被引量:27
6
作者 朱祖超 谢鹏 +2 位作者 偶国富 崔宝玲 李昳 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第4期528-534,共7页
The design method of small-flow high-head centrifugal-vortex pump was presented. This pump, configured with inducer, complex-centrifugal impeller and open-vortex impeller, was put forward to deliver gas-liquid two-pha... The design method of small-flow high-head centrifugal-vortex pump was presented. This pump, configured with inducer, complex-centrifugal impeller and open-vortex impeller, was put forward to deliver gas-liquid two-phase mixture. An HTB-5/60 type sample pump was developed and tested on a closed-loop test rig. Experimental studies on performance and cavitation tests for gas-liquid two-phase mixture were carried out compared with pure-water experimental results. Also the effect of gas phase on pump was analyzed and discussed. The experimental results show that performance and cavitation characteristics of the sample purnp deteriorates progressively with increasing volume fraction of gas. When the total capacity Qm is between 4.5 m^3·h^-1 and 6 m^3·h^-1 and the gas flow rate qg below 0.66 m^3·h^-1, or qg/Qm is lower than 15%, the characteristic curves are approximately parallel to those in pure water test, but the performance deteriorates sharply until an abrupt flow-cutting at a critical volume fraction of gas. This pump is found suitable for transporting gas-liquid two-phase mixture when working around rated capacity of 5 m^3·h^-1 with qglQm below 15%. 展开更多
关键词 centrifugal-vortex pump gas-liquid two-phase flow performance and cavitation test
下载PDF
Differential cognitive responses to guqin music and piano music in Chinese subjects: an event-related potential study 被引量:9
7
作者 Wei-Na ZHU Jun-Jun ZHANG +3 位作者 Hai-Wei LIU Xiao-Jun DING Yuan-Ye MA Chang-Le ZHOU 《Neuroscience Bulletin》 SCIE CAS CSCD 2008年第1期21-28,共8页
Objective To compare the cognitive effects of guqin (the oldest Chinese instrument) music and piano music. Methods Behavioral and event-related potential (ERP) data in a standard two-stimulus auditory oddball task... Objective To compare the cognitive effects of guqin (the oldest Chinese instrument) music and piano music. Methods Behavioral and event-related potential (ERP) data in a standard two-stimulus auditory oddball task were recorded and analyzed. Results This study replicated the previous results of culture-familiar music effect on Chinese subjects: the greater P300 amplitude in frontal areas in a culture-familiar music environment. At the same time, the difference between guqin music and piano music was observed in NI and later positive complex (LPC: including P300 and P500): a relatively higher participation of right anterior-temporal areas in Chinese subjects. Conclusion The results suggest that the special features of ERP responses to guqin music are the outcome of Chinese tonal language environments given the similarity between Guqin's tones and Mandarin lexical tones. 展开更多
关键词 music GUQIN PIANO cognitive process event-related potential (ERP) NI LPC P300
下载PDF
Morphological Changes in Nucellar Cells Undergoing Programmed Cell Death (PCD) During Pollen Chamber Formation in Ginkgo biloba 被引量:1
8
作者 李大辉 杨雄 +1 位作者 崔克明 李正理 《Acta Botanica Sinica》 CSCD 2003年第1期53-63,共11页
Programmed cell death (PCD) of the nucellar cells at the micropylar end is involved in pollen chamber morphogenesis in Ginkgo biloba L. A development-course observation of the morphological changes in the nucellar cel... Programmed cell death (PCD) of the nucellar cells at the micropylar end is involved in pollen chamber morphogenesis in Ginkgo biloba L. A development-course observation of the morphological changes in the nucellar cells undergoing PCD to form pollen chamber was performed. During the PCD, the nucellar cells degraded their cellular components through an orderly progression. Through the vactiolation, the cytosol was engulfed by the enlarging vacuole, leaving out various organelles, which remained morphologically integrated. As the vacuolation continued, the vacuole collapsed with the breakage of the tonoplast and the cytosol disappeared completely. Organelles were subsequently destroyed. Ultimately, nucellar cells digested away all of their cytoplasm, leaving with cell walls. They became collapsed as the nucellus developed. Intracellular membranes were strikingly changed, playing a role in leading to cell death. Some of these noticeable changes were the appearance of multivesicular body, multicycle-like membranes, membrane-bounded bodies containing some organelles, tonoplast rupture and numerous vesicles. The dehiscence of the apical epidermis, resulting in the opening, appeared to have followed two different pathways with one involving a specific epidermal cell autolysis and the other by detachment from middle lamella of two neighboring epidermal cells without cell autolysis. The specific epidermal cells had been dead prior to the dehiscence of the apical epidermis, which marked the sites of the dehiscence followed. In view of the changes in the cellular morphology, a process of nucellar cell PCD in the course of the pollen chamber formation was demonstrated. 展开更多
关键词 Ginkgo biloba nucellar cell pollen chamber programmed cell death (PCD)
下载PDF
NUMERICAL SIMULATIONS OF EVOLUTIONS FROM WALL PULSE TO TURBULENT COHE RENT STRUCTURES
9
作者 张立 唐登斌 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2003年第1期17-22,共6页
The high order compact d if ference method is developed for solving the perturbation equations based on Navi er Stokes equations, and is used in studying complex evolution processes from w all negative pulse to the ... The high order compact d if ference method is developed for solving the perturbation equations based on Navi er Stokes equations, and is used in studying complex evolution processes from w all negative pulse to the turbulent coherent structure in the channel flow. Th is method contains three dimensional coupling difference scheme with high accur acy and high resolution, and the high order time splitting methods. Compared with the general spectral method, the method can be used to research turbule nt coherent structure under more general boundary conditions and in flow domains . In this paper, the generation and evolution of the turbulent coherent structur es ind uced by wall pulse in the channel flow are simulated, and the basic characterist ics and rules of the turbulent coherent structure are shown. Computational r esults indicate that a wall negative pulse is more convenient than the resonant three wave model. 展开更多
关键词 coherent structure TURBULENCE Navier Stokes equations three dimensional coupling difference sc heme high order time splitting method
下载PDF
The future of remote ECG monitoring systems 被引量:8
10
作者 Shu-LI GUO Li-Na HAN +3 位作者 Hong-Wei LIU Quan-Jin SI De-Feng KONG Fu-Su GUO 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2016年第6期528-530,共3页
Remote ECG monitoring systems are becoming commonplace medical devices for remote heart monitoring. In recent years, remote ECG monitoring systems have been applied in the monitoring of various kinds of heart diseases... Remote ECG monitoring systems are becoming commonplace medical devices for remote heart monitoring. In recent years, remote ECG monitoring systems have been applied in the monitoring of various kinds of heart diseases, and the quality of the transmission and re- ception of the ECG signals during remote process kept advancing. However, there remains accompanying challenges. This report focuses on the three components of the remote ECG monitoring system: patient (the end user), the doctor workstation, and the remote server, reviewing and evaluating the imminent challenges on the wearable systems, packet loss in remote transmission, portable ECG monitoring system, pa- tient ECG data collection system, and ECG signals transmission including real-time processing ST segment, R wave, RR interval and QRS wave, etc. This paper tries to clarify the future developmental strategies of the ECG remote monitoring, which can be helpful in guiding the research and development of remote ECG monitoring. 展开更多
关键词 Cardiovascular system ECG Remote monitoring
下载PDF
High Serum Resistin Level may be an Indicator of the Severity of Coronary Disease in Acute Coronary Syndrome 被引量:16
11
作者 Hao Wang De-you Chen +3 位作者 Jian Cao Zuo-yun He Bing-po Zhu Min Long 《Chinese Medical Sciences Journal》 CAS CSCD 2009年第3期161-166,共6页
Objective To investigate the correlation between serum resistin level, cardiovascular risk factors and severity of coronary disease in acute coronary syndrome (ACS). Methods Alter evaluated by clinical history, ele... Objective To investigate the correlation between serum resistin level, cardiovascular risk factors and severity of coronary disease in acute coronary syndrome (ACS). Methods Alter evaluated by clinical history, electrocardiography, exercise tolerance tests, laboratory tests, and coronary angiography, 220 consecutive patients with suspected chest pain were divided into normal control group, stable angina pectoris (SAP) group, and ACS group, respectively. Baseline clinical characteristics, including height, weight, waist circumference, hip circumference, white blood cell count, high-sensitive C-reactive protein (hsCRP), total cholesterol, triglyceride, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol, were compared among three groups. ELISA was used to detect serum resistin levels. Pearson's correlation coefficient analysis was used to assess association between resistin and other traditional cardiovascular risk factors. Multinomial logistic regression analyses were used to define the relationship between serum resistin level and SAP or ACS. Results Serum resistin level in ACS group (1.18±0.48 μg/L) was significantly higher than that in normal control and SAP groups (0.49±0.40 and 0.66±0.40 μg/L; P〈0.01). Only in ACS group, increased serum resistin level was significantly correlated with hsCRP (r=0.262, P=0.004) and white blood cell count (r=0.347, P=0.001). Furthermore, serum resistin levels showed a stepwise increase with the number increase of 〉 50% stenosed coronary vessels. Multinomial logistic regression test demonstrated that serum resistin was a strong risk factor for ACS (OR=29.132, 95 % CI: 10.939-77.581, P〈0.001). Conclusion These findings suggested the potential role of resistin in atherosclerosis and especially its involvement in ACS. 展开更多
关键词 RESISTIN ATHEROSCLEROSIS acute coronary syndrome stable angina pectoris
下载PDF
Remote State Preparation of a Greenberger-Horne-Zeilinger Class State 被引量:4
12
作者 ZHANYou-Bang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第4期637-640,共4页
In this paper, we propose a scheme for the remote preparation of a three-particle Greenberger-HorneZeilinger class state by a two-particle entangled state and a three-particle entangled state. It is shown that, by thi... In this paper, we propose a scheme for the remote preparation of a three-particle Greenberger-HorneZeilinger class state by a two-particle entangled state and a three-particle entangled state. It is shown that, by this scheme, only two classical bits and one two-particle projective measurement are enough for such preparation. 展开更多
关键词 remote state preparation Greenberger-Horne- Zeilinger state ENTANGLEMENT
下载PDF
The serum anion gap is associated with disease severity and all-cause mortality in coronary artery disease 被引量:6
13
作者 Shi-Wei YANG Yu-Jie ZHOU +15 位作者 Ying-Xin ZHAO Yu-Yang LIU Xiao-Fang TIAN Zhi-Jian WANG De-An JIA Hong-Ya HAN Bin HU Hua SHEN Fei GAO Lu-Ya WANG Jie LIN Guo-Zhong PAN Jian ZHANG Zhen-Feng GUO Jie DU Da-Yi HU 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2017年第6期392-400,共9页
Objective To evaluate the associations between the serum anion gap (AG) with the severity and prognosis of coronary artery disease (CAD). Methods We measured serum electrolytes in 18,115 CAD patients indicated by ... Objective To evaluate the associations between the serum anion gap (AG) with the severity and prognosis of coronary artery disease (CAD). Methods We measured serum electrolytes in 18,115 CAD patients indicated by coronary angiography. The serum AG was calculated according to the equation: AG = Na^+ [(mmol/L) + K^+ (mmol/L)] - [Cl^- (mmol/L) + HCO3^- (mmol/L)]. Results A total of 4510 (24.9%) participants had their AG levels greater than 16 mmol/L. The serum AG was independently associated with measures of CAD severity, including more severe clinical types of CAD (P 〈 0.001) and worse cardiac function (P = 0.004). Patients in the 4th quartile of serum AG (≥ 15.92 mmol/L) had a 5.171-fold increased risk of 30 days all-cause death (P 〈 0.001). This association was robust, even after adjustment for age, sex, evaluated glomerular filtration rate [hazard ratio (HR): 4.861, 95% confidence interval (CI): 2.150–10.993, P 〈 0.001], clinical diagnosis, severity of coronary artery stenosis, cardiac function grades, and other confounders (HR: 3.318, 95% CI: 1.76–2.27, P = 0.009). Conclusion In this large population-based study, our findings reveal a high percentage of increased serum AG in CAD. Higher AG is associated with more severe clinical types of CAD and worse cardiac function. Furthermore, the increased serum AG is an independent, significant, and strong predictor of all-cause mortality. These findings support a role for the serum AG in the risk-stratification of CAD. 展开更多
关键词 All-cause death Anion gap Coronary artery disease
下载PDF
The minglement of sense and sensibility, he combination of ambition and aspiration ——Comment on A biography of Napoleon
14
作者 刘昱君 《Sino-US English Teaching》 2009年第7期63-65,共3页
A Biography of Napoleon, which is based on historical events, presents the readers a complicated, confident and imaginative Napoleon by depicting his mental progression, during which he works his miracle with his aspi... A Biography of Napoleon, which is based on historical events, presents the readers a complicated, confident and imaginative Napoleon by depicting his mental progression, during which he works his miracle with his aspiration, ambition and personal charm in the military history. 展开更多
关键词 NAPOLEON mental progression ASPIRATION AMBITION personal charm
下载PDF
Advances in Studies and Applications of Centroidal Voronoi Tessellations 被引量:6
15
作者 Qiang Du Max Gunzburger Lili Ju 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2010年第2期119-142,共24页
Centroidal Voronoi tessellations(CVTs) have become a useful tool in many applications ranging from geometric modeling,image and data analysis,and numerical partial differential equations,to problems in physics,astroph... Centroidal Voronoi tessellations(CVTs) have become a useful tool in many applications ranging from geometric modeling,image and data analysis,and numerical partial differential equations,to problems in physics,astrophysics,chemistry,and biology. In this paper,we briefly review the CVT concept and a few of its generalizations and well-known properties.We then present an overview of recent advances in both mathematical and computational studies and in practical applications of CVTs.Whenever possible,we point out some outstanding issues that still need investigating. 展开更多
关键词 Voronoi tessellations CENTROIDS CLUSTERING mesh generation and optimization IMAGEPROCESSING model reduction point sampling.
下载PDF
Long-term results of single-procedure catheter ablation for atrial fibrillationin pre-and post-menopausal women 被引量:5
16
作者 Tao LIN Xing DU Rong BAI Ying-Wei CHEN Rong-Hui YU De-Yong LONG Ri-Bo TANG Cai-Hua SANG Song-Nan LI Chang-Sheng MA Jian-Zeng DONG 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2014年第2期120-125,共6页
Objectives To address whether menopause affects outcome of catheter ablation (CA) for atrial fibrillation (AF) by comparing the safety and long-term outcome of a single-procedure in pre-and post-menopausal women. ... Objectives To address whether menopause affects outcome of catheter ablation (CA) for atrial fibrillation (AF) by comparing the safety and long-term outcome of a single-procedure in pre-and post-menopausal women. Methods A total of 743 female patients who underwent a single CA procedure of drug-refractory AF were retrospectively analyzed. The differences in clinical presentation and outcomes of CA for AF between the pre-menopausal women (PreM group, 94 patients, 12.7%) and the post-menopausal women (PostM group, 649 patients, 87.3%) were assessed. Results The patients in the PreM group were younger (P&lt;0.001) and less likely to have hypertension (P&lt;0.001) and diabetes (P=0.005) than those in the PostM group. The two groups were similar with regards to the proportion of concomitant mitral valve regurgitation coronary artery disease, left atrium dimensions, and left ventricular ejection fraction. The overall rate of complica-tions related to AF ablation was similar in both groups (P=0.385). After 43 (16-108) months of follow-up, the success rate of ablation was 54.3%in the PreM group and 54.2%in the PostM group (P=0.842). The overall freedom from atrial tachyarrhythmia recurrence was simi-lar in both groups. Menopause was not found to be an independent predictive factor of the recurrence of atrial tachyarrhythmia. Conclusions The long-term outcomes of single-procedure CA for AF are similar in pre-and post-menopausal women. Results indicated that CA of AF appears to be as safe and effective in pre-menopausal women as in post-menopausal women. 展开更多
关键词 Atrial fibrillation Catheter ablation FOLLOW-UP Menopausal woman
下载PDF
Measurement of Tip Trajectories in the Cardiac Reentry 被引量:1
17
作者 MING Le-qun ZHANG Hong +1 位作者 PENG Nian-cai LI Ming-jun 《Chinese Journal of Biomedical Engineering(English Edition)》 2008年第3期134-138,共5页
Reentrant impulse in the myocardium is considered to be a major factor promoting electrophysiological abnormalities or even leading to ventricular tachycardias (VTs) and ventricular fibrillations (VFs). Tip trajectory... Reentrant impulse in the myocardium is considered to be a major factor promoting electrophysiological abnormalities or even leading to ventricular tachycardias (VTs) and ventricular fibrillations (VFs). Tip trajectory of the reentrant wave can reflect stability of the electrical propagation and area of the reentrant movement, thereby being considered as one of the most concerned parameters in studying electrical activities during VT/VF. The purpose of the present study is to propose a practical method to find out tip trajectories using a computational approach. In this study Luo-Rudy 1991 mathematical model of the ventricular cell was used. The operator splitting method was utilized to integrate the partial differential equations in the two-dimensional tissue. And spiral waves were initiated by the cut wave front technique. Through experiments we found it was difficult to find out the tips by finding intersection of the two isovoltage lines as proposed in most papers. Therefore, we suggested that tip points were detected by seeking the shortest distance of the two adjacent isovoltage contour lines. The results showed that tip trajectories of these spiral waves found in our way were very near to the tips observed, implying validation of our method in measuring tip trajectories in cardiac reentry. 展开更多
关键词 spiral wave tip trajectory REENTRY computer simulation
下载PDF
Four basic laws in design science 被引量:4
18
作者 Xie Youbai 《Engineering Sciences》 EI 2014年第2期2-8,28,共8页
A point on the distinction between design and science is given and the connotanons of aeslgn science are discussed in the paper. Design should be understood as the first step of all human' s purposeful activity, whic... A point on the distinction between design and science is given and the connotanons of aeslgn science are discussed in the paper. Design should be understood as the first step of all human' s purposeful activity, which is a daily behavior for everyone. Four laws are summarized, which describe the basic patterns of design and are the constituents of design science. They are the law of design based on existed knowledge, law of in- completeness of design knowledge, law of design centered on new knowledge acquirement and law of competi- tiveness of design knowledge. The four basic laws show the knowledge essence of design. To enrich the existed knowledge, to make it convenient to be used, to teach designers with high intuition and inspiration in picking useful elements of existed knowledge and shaping competitive ideas and to have strong new knowledge acquire- ment facility are the basic conditions of good designs. Study of design science will promote the structure of tra- ditional engineering education. An important conclusion is derived that there will be no successful innovation without good design. 展开更多
关键词 DESIGN design science KNOWLEDGE knowledge flow
下载PDF
Using Impervious Surfaces to Detect Urban Expansion in Beijing of China in 2000s 被引量:12
19
作者 PENG Jian LIU Yanxu +3 位作者 SHEN Hong XIE Pan HU Xiaoxu WANG Yanglin 《Chinese Geographical Science》 SCIE CSCD 2016年第2期229-243,共15页
The change of impervious surface area(ISA) can effectively reveal the gradual process of urbanization and act as a key index for monitoring urban expansion. Experiencing rapid growth of the built environment in the 20... The change of impervious surface area(ISA) can effectively reveal the gradual process of urbanization and act as a key index for monitoring urban expansion. Experiencing rapid growth of the built environment in the 2000 s, urban expansion of Beijing has not been fully characterized through ISA. In this study, Landsat TM images of Beijing in 2001 and 2009 were obtained, and the eight-year urban expansion process in Beijing was analyzed using the ISA extracted by means of the vegetation-imperious surface-soil(V-I-S) model. From the spatial variation in ISA, the ring structure of urban expansion in Beijing was significant during the study period, with decreasing urban density from the city center to the periphery. In the ring road analysis, the most dramatic changes of ISA were found between the fifth ring and the sixth ring. This area has experienced the most new residential development, and is currently the main source of urban expansion. The typical profile lines revealed the directional characteristics of urban expansion. The east-west profile was the most urbanized axes in Beijing, while ISA change in the east-north profile was more significant than in the other five profiles. Moreover, the transition matrix of ISA levels revealed an increase in urban density in the low density built areas; the Moran′s I index showed a clear expansion of the central urban area, which spread contiguously; and the standard deviational ellipse indicated the northeast was the dominant direction of urban expansion. These findings can provide important spatial control guidelines in the next round of national economic and social development planning, overall urban and rural planning, and land use planning. 展开更多
关键词 impervious surface area(ISA) vegetation-imperious surface-soil(V-I-S) model profile line analysis urban expansion direction Beijing China
下载PDF
Tuning the mechanosensitivity of a BK channel by changing the linker length 被引量:6
20
作者 Hucheng Zhao 《Cell Research》 SCIE CAS CSCD 2008年第8期871-878,共8页
Some large-conductance Ca^2+ and voltage-activated K^+(BK) channels are activated by membrane stretch. However, the mechanism of mechano-gating of the BK channels is still not well understood. Previous studies hav... Some large-conductance Ca^2+ and voltage-activated K^+(BK) channels are activated by membrane stretch. However, the mechanism of mechano-gating of the BK channels is still not well understood. Previous studies have led to the proposal that the linker-gating ring complex functions as a passive spring, transducing the force generated by intracellular Ca^2+ to the gate to open the channel. This raises the question as to whether membrane stretch is also transmitted to the gate of mechanosensitive (MS) BK channels via the linker-gating complex. To study this, we changed the linker length in the stretch-activated BK channel (SAKCaC), and examined the effect of membrane stretch on the gating of the resultant mutant channels. Shortening the linker increased, whereas extending the linker reduced, the channel mechanosensitivity both in the presence and in the absence of intracellular Ca^2+. However, the voltage and Ca^2+ sensitivities were not significantly altered by membrane stretch. Furthermore, the SAKCaC became less sensitive to membrane stretch at relatively high intracellular Ca^2+ concentrations or membrane depolarization. These observations suggest that once the channel is in the open-state conformation, tension on the spring is partially released and membrane stretch is less effective. Our results are consistent with the idea that membrane stretch is transferred to the gate via the linker-gating ring complex of the MS BK channels. 展开更多
关键词 BK channel mechanosensitive channel mechano-gating HEART
下载PDF
上一页 1 2 6 下一页 到第
使用帮助 返回顶部