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Search Results: 1 - 10 of 15064 matches for " Yunlai Ren "
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GC-MS analysis of essential oil of Paeonia suffruticosa Andrews from ZhaoFen and RouFurong flowers in China  [PDF]
Weiping Yin, Wenlu Duan, Pu Liu, Ruixue Deng, Yunlai Ren, Shuang Zhao
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.48073
Abstract: The flowers of ZhaoFen and RouFurong may contain essential oils with natural aromatic ingredients. In the present work, the chemical compositions of essential oil of Paeonia suffruticosa Andrews from the flowers of ZhaoFen and RouFurong grown only in China were investigated by GC-MS analysis. The results indicate that there are 27 constituents in ZhaoFen and 29 constituents in RouFurong, which account for 96.04% and 95.90% of the oils of ZhaoFen and RouFurong, respectively. The major components of the essential oils are character-rized by oxygenated terpenols, and their content is, respectively, 85.06% and 83.47%. The essential oil of Paeonia suffruticosa Andrews was reported for the first time on the aerial parts.
Serum Angiopoietin-2 and β-hCG as Predictors of Prolonged Uterine Bleeding after Medical Abortion in the First Trimester
Maofeng Wang, Junqing Chen, Jun Ying, Jiong Yu, Bifei Huang, Zhaoxiang Ren, Xianyu Wang, Qiaoqiao Guo, Yunlai Wang, Liuyi Qiu, Hongsheng Yu, Rugen Wan
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063755
Abstract: Objective The combination of mifepristone and misoprostol is an established method for induction of early first trimester abortion, but there is no consensus about the best evaluation of treatment outcome. We evaluate serum Angiopoietin-2(Ang-2) and β human chorionic gonadotropin (β-hCG) in women who had undergone a medical abortion as markers of prolonged uterine bleeding (PUB). Methods Prospective trial involving 2843 women attending an gynecology outpatient clinic who following a medical abortion with mifepristone and misoprostol, the study cohort was divided into women with duration of uterine bleeding >14 days (PUB) and women with duration of uterine bleeding ≤14 days (normal uterine bleeding, NUB). Serum determinations of Ang-2 levels by ELISA and β-hCG levels by electrochemiluminiscence immunoassay. Receiver Operating Characteristics (ROC) analyses were calculated and plotted for the diagnostic accuracy of serum β-hCG and Ang-2 concentration to discriminate PUB and NUB. Results Baseline characteristics for both groups were similar, Only duration of bleeding showed a significant difference between the PUB group and NUB group. Ang-2 serum levels moderately correlated with serum β-hCG levels with statistically significant correlation coefficients of 0.536. Serum β-hCG and Ang-2 levels on day 7 and on day 14 after medical abortion were signifcantly higher in PUB group than in NUB group. Plotted as ROC curves, β-hCG area under curve (AUC) was 0.65 (95% CI, 0.53–0.76) on day 7, rising to AUC = 0.83 (95% CI, 0.75–0.92) on day 14. Using Ang-2 on day 7 and day 14 as predictive parameter resulted in an analogous AUC (AUC = 0.61 on day 7, AUC = 0.78 on day 14). Conclusions Both parameters are clinically useful as a diagnostic test in predicting PUB after medical abortion, and can be helpful in uncertain clinical situations, but should be considered as supplementary to a general clinical evaluation.
Turned off Characteristics of Linear Ultrasonic Motor
Zhang Jun, Shi Yunlai, Niu Zijie, Liang Dazhi
- , 2017, DOI: 10.16356/j.1005-1120.2017.01.049
Abstract: The high controllability and high resolution control of linear ultrasonic motors depend on effective control of driving signals. For a good control characteristic, step control which the driver output turned off and on was used. Therefore, a novel dual PWM topology structure ultrasonic motor driver was designed and analyzed. According to the characteristics of the circuits, two kinds of hardware turned off methods named methods A and B were discussed. The differences of the voltage applied on motor by different methods were figured out. Finally, a series of experiments were carried out in the clean room to study the influence of step characteristic by different turn off methods. The experimental results show that the steplength was 230 nm by method A and 125 nm by method B, while cycles of driving signals were 6. The method B has a smaller steplength when cycles are 6. The average steplength varies in non-linear while driving cycles changing. The steplength varies approximately in linear while voltage amplitude changing. Therefore, method B is better to implement step control, because it gets a better control in positioning system.
Stick-Slip Tower-Shaped Piezoelectric Actuator
Chen Qianwei, Ju Quanyong, Huang Weiqing, Shi Yunlai
- , 2015, DOI: 10.16356/j.1005-1120.2015.02.156
Abstract: Since stick-slip actuators present the advantage of allowing long displacements (several centimeters or even more) at a high speed with an ultra high resolution (<5 nm), a new type of stick-slip piezoelectric actuator is proposed to attain sub-nanometer positioning accuracy. The actuator is composed of a slider and a tower-shaped stator using forced bending vibration in y-z plane to generate tangential vibration on the top of the driving foot. When excited by the sawtooth input voltage, driving foot of the stator is able to generate a tangential asymmetrical vibration on the top, and the slider is thus pushed to move. A prototype and its testing equipment are fabricated and described. Following that, the testing of vibration mode and mechanical characteristics as well as stepping characteristics are conducted. Experimental results show that under the condition that the sawtooth input voltage is 400 VP-P and the pre-pressure is 6 N. Velocity of the actuator reaches its maximum 1.2 mm/s at the frequency of 8 000 Hz and drops to its minimum 35 nm/s at the frequency of 1 Hz. When the excitation signal is the single-phase sawtooth stepping signal, the tower-shaped actuator can directionally move forward or backward step by step. And when excited by the sawtooth stepping signal with 1 Hz and 300 VP-P during 1 cycle (200 ms), the actuator has a minimum stepping distance of 22 nm.
Fibonacci Congruences and Applications  [PDF]
René Blacher
Open Journal of Statistics (OJS) , 2011, DOI: 10.4236/ojs.2011.12015
Abstract: When we study a congruence T(x) ≡ ax modulo m as pseudo random number generator, there are several means of ensuring the independence of two successive numbers. In this report, we show that the dependence depends on the continued fraction expansion of m/a. We deduce that the congruences such that m and a are two successive elements of Fibonacci sequences are those having the weakest dependence. We will use this result to obtain truly random number sequences xn. For that purpose, we will use non-deterministic sequences yn. They are transformed using Fibonacci congruences and we will get by this way sequences xn. These sequences xn admit the IID model for correct model.
The Third Kind Of Particles  [PDF]
ShaoXu Ren
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.59090

There are two kinds of spin particles in nature, the Boson and the Fermion.(For more information, please refere to the PDF.)

The Origins of Bosons and Fermions  [PDF]
ShaoXu Ren
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.517181
Abstract: This paper proposes that all Bosons and all Fermions originate from even more elementary constituents, which called Spin Angular Momentum Vacuum (SAMV). SAMV is filled with Primitive Spin Particles (PSP). The total square spin angular momentum of each PSP is negative, less than zero. Those PSP labeled by index \"\" of Casimir Operator, are called Vacuum Spin Particle (VSP), which could be contracted into so-called Vacuum Bubbles (VB). VB are identical bubbles, are \"sub-observable physical quantities\". VB are paired up into Vacuum Bubble Pair VBP. VSP ωj(or ω+-) results from Self-identical vacuum bubble interaction \"\" through the zero order Phase Transition PT. When the 1st, 2nd, 3rd,... order PT of VBP occur,  then VBP turn into Bosons and Fermions, excited out of sea level of SAMV ocean.
An Integrated Intrusion Detection System by Combining SVM with AdaBoost  [PDF]
Yu Ren
Journal of Software Engineering and Applications (JSEA) , 2014, DOI: 10.4236/jsea.2014.712090
Abstract: In the Internet, computers and network equipments are threatened by malicious intrusion, which seriously affects the security of the network. Intrusion behavior has the characteristics of fast upgrade, strong concealment and randomness, so that traditional methods of intrusion detection system (IDS) are difficult to prevent the attacks effectively. In this paper, an integrated network intrusion detection algorithm by combining support vector machine (SVM) with AdaBoost was presented. The SVM is used to construct base classifiers, and the AdaBoost is used for training these learning modules and generating the final intrusion detection model by iterating to update the weight of samples and detection model, until the number of iterations or the accuracy of detection model achieves target setting. The effectiveness of the proposed IDS is evaluated using DARPA99 datasets. Accuracy, a criterion, is used to evaluate the detection performance of the proposed IDS. Experimental results show that it achieves better performance when compared with two state-of-the-art IDS.
Novel Understanding of Electron States Architecture and Its Dimensionality in Semiconductors  [PDF]
Xiaomin Ren
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.32B075

Some important insights into the electron-states-architecture (ESA) and its dimensionality (from 3 to 0) in a semiconductor (or generally crystalline) material are obtained. The self-consistency of the set of density of states (DOS) expressions with different dimensionalities is remediated through the clarification and rearrangement of the wave-function boundary conditions for working out the eigenvalues in the wave vector space. The actually too roughly observed and theoretically unpredicted critical points for the dimensionality transitions referring to the integer ones are revealed upon an unusual assumption of the intrinsic energy-level dispersion (ELD). The ELD based quantitative physical model had been established on an immediate instinct at the very beginning and has been properly modified afterwards. The uncertainty regarding the relationship between the de Broglie wavelength of electrons and the dimensionality transitions, seeming somewhat mysterious before, is consequentially eliminated. The effect of the material dimensions on the ELD width is also predicted and has been included in the model. The continuous evolution of the ESA dimensionality is convincingly and comprehensively interpreted and thus the area of the fractional ESA dimensionalities is opened. Another new assumption of the spatial extension shrinkage (SES) closely related to the ELD has also been made and thus the understanding of the behavior of an electron or, in a general sense, a particle has become more comprehensive. This work would manifest itself a new basis for further development of nanoheterostructures (or low dimensional heterostructures including the quantum wells, quantum wires, quantum dots and especially the hetero-dimensional structures). Expected

Hurricane Camille 1969 and Storm-Triggered Landslides in the Appalachians and a Perspective in a Warmer Climate  [PDF]
Diandong Ren
International Journal of Geosciences (IJG) , 2016, DOI: 10.4236/ijg.2016.71006
Abstract: This study analyzes storm-triggered landslides in the US Appalachians, in the current geological setting. Concave valleys that favor the convergence of surface runoff are the primary locales for landslides. If the slopes are weathered to the same degree and have the same vegetation coverage, slope orientation (azimuthal) is not critical for slope stability. However, it is found that for the region south of the Black Mountains (North Carolina), north-facing slopes are more prone to slide, because, for the regions not limited by water availability (annual precipitation), the northern slopes usually are grass slopes. For the slopes of the Blue Ridge Mountains, south facing slopes are more prone to slide. Gravity measurements over the past decade reveal that geological conditions, the chute system and underground cracks over the region are stable. Future changes in storm-triggered landslide frequency are primarily controlled by changes in extreme precipitation. Thus, a series of ensemble climate model experiments is carried out to investigate possible changes in future extreme precipitation events, using a weather model forced by atmospheric perturbations from ensemble climate models. Over 50 locations are identified as prone to future landslides. Many of these locales are natural habitats to the Appalachian salamanders. In a future warmer climate, more severe extreme precipitation events are projected because of increased atmospheric water vapor and more frequent passages of tropical cyclone remnants. There is also a likely shift of tropical cyclone tracks and associated extreme precipitations, and the cluster center of Appalachians’s scarps is expected to move westward, with ecological consequences for the endemic salamanders.
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