A new double reduction method for slope stability analysis

The core of strength reduction method(SRM) involves finding a critical strength curve that happens to make the slope globally fail and a definition of factor of safety(FOS). A new double reduction method, including a detailed calculation procedure and a definition of FOS for slope stability was developed based on the understanding of SRM. When constructing the new definition of FOS, efforts were made to make sure that it has concise physical meanings and fully reflects the shear strength of the slope. Two examples, slopes A and B with the slope angles of 63° and 34° respectively, were given to verify the method presented. It is found that, for these two slopes, the FOSs from original strength reduction method are respectively 1.5% and 38% higher than those from double reduction method. It is also found that the double reduction method predicts a deeper potential slide line and a larger slide mass. These results show that on one hand, the double reduction method is comparative to the traditional methods and is reasonable, and on the other hand, the original strength reduction method may overestimate the safety of a slope. The method presented is advised to be considered as an additional option in the practical slope stability evaluations although more useful experience is required.

Double Symplectic Eigenfunction Expansion Method of Free Vibration of Rectangular Thin Plates

The free vibration problem of rectangular thin plates is rewritten as a new upper triangular matrix differential system. For the associated operator matrix, we find that the two diagonal block operators are Hamiltonian. Moreover, the existence and completeness of normed symplectic orthogonal eigenfunction systems of these two block operators are demonstrated. Based on the completeness, the general solution of the free vibration of rectangular thin plates is given by double symplectie eigenfunction expansion method.

Simulation of crack coalescence mechanism underneath single and double disc cutters by higher order displacement discontinuity method

The present research is focused on the numerical crack coalescence analysis of the micro-cracks and cracks produced during the cutting action of TBM disc cutters. The linear elastic fracture mechanics(LEFM) concepts and the maximum tangential stress criterion are used to investigate the micro crack propagation and its direction underneath the excavating discs. A higher order displacement discontinuity method with quadratic displacement discontinuity elements is used to estimate the stress intensity factors near the crack tips. Rock cutting mechanisms under single and double type discs are simulated by the proposed numerical method.The main purposes of the present modeling are to simulate the chip formation process of indented rocks by single and double discs.The effects of specific disc parameters(except speed) on the thrust force Ft, the rolling force Fr, and the specific energy ES are investigated. It has been shown that the specific energy(energy required to cut through a unit volume of rock) of the double disc is less than that of the single disc. Crack propagation in rocks under disc cutters is numerically modeled and the optimum ratio of disc spacing S to penetration depth Pd(i.e. S/Pd ratio) of about 10 is obtained, which is in good agreement with the theoretical and experimental results cited in the literature.

Research on Design Method of Non-Circular Gear Pair with Double Generating Angles

In order to enhance the bearing capacity of non-circular gear pair, the non-circular gear pair with double generating angles is proposed based on the design idea of unsymmetrical gear with double pressure angles. The tooth profile is designed by generating cutting theory, the pure rolling mathematic model that the center line of unsymmetrical rack roll along non-circular pitch curve is built, the digital model of non-circular gear with double generating angles is created through the second development method of CAD software, and then the drive characteristic and tooth strength are analyzed. The results show that the design method for double generating angles non-circular gear proposed in this paper is feasible, which is significant to improve the bearing capacity of non-circular gear pair.

Single dose dexamethasone prophylaxis of postembolisation syndrome after chemoembolisation in hepatocellular carcinoma patient:A randomised,double-blind,placebo-controlled study

BACKGROUND Even in the immuno-oncology era,transcatheter arterial chemoembolisation(TACE)is the most effective way to treat intermediate stage hepatocellular carcinoma(HCC).Postembolisation syndrome(PES)is the most common side effect from TACE and there is still no standard prevention guideline.AIM To evaluate the efficacy of single dose intravenous dexamethasone regimen to prevent PES after TACE among patients with HCC.METHODS This study enrolled patients with HCC who had eligible indication for TACE without macrovascular invasion/extrahepatic metastasis.Patients were randomly assigned to either an intravenous single dose of dexamethasone 8 mg or placebo one hour before TACE.The primary outcome was a negative result of PES at 48 h after TACE,which was defined as score<2 of Southwest Oncology Group toxicity coding criteria using fever,nausea,vomiting and pain to calculated.And the secondary end point was duration of admission between two groups.RESULTS One hundred patients were randomly assigned 1:1.Under intention-to-treat analysis,49 patients were randomly assigned to the dexamethasone and 51 to the placebo groups.Both groups were similar for baseline characteristics.The negative PES rate was significantly higher in the dexamethasone group than in the placebo group(63.3%vs 29.4%;P=0.005).Mean Southwest Oncology Group toxicity coding PES was 2.14(95%CI:1.41-2.8)vs 3.71(95%CI:2.97-4.45)between the dexamethasone and placebo groups,respectively.Cumulative incidence of fever was significantly lower in dexamethasone group with P<0.001,pain,nausea and vomiting were also lower in the dexamethasone group compared with the placebo group(P=0.16,P=0.11,and P=0.49).The dexamethasone regimen was generally well tolerated by patients with HCC patients including those with hepatitis B virus infection and well-controlled diabetes mellitus.CONCLUSION Single dose dexamethasone was effective at preventing PES among patients with HCC treated with TACE.The study showed no adverse events of special interest related to dexamethasone.

Estimation of conservation value of myrtle(Myrtus communis)using a contingent valuation method:a case study in a Dooreh forest area,Lorestan Province,Iran

Background： Around 2000 plant species occur naturally in Lorestan Province of which 250 species are medicinal and myrtle is one of them. Myrtle is a shrub whose leaves and fruits have medicinal value and thus, if managed and harvested properly, could produce sustained economic benefits. In recent years, however, over half of the myrtle site areas was destroyed, due to inappropriate management and excessive harvesting practices. Thus, coming up with a practical harvesting approach along with identifying those factors damaging the sites, seems to be very crucial. Methods： In our investigation, we calculated the conservation value per hectare of myrtle in the Dooreh forest area in Lorestan Province. Using the Contingent Valuation （CV） and Double Bounded Dichotomous Choice （DBDC） methods, we determined the willingness to pay （VVTP） for myrtle conservation. The VVTP was estimated with a Iogit model for which indices were obtained based on a maximum precision criterion. Results： The results showed that 86.67 per cent of people were willing to pay for the conservation of these myrtle sites. Average monthly WTP per family was calculated as $0.79. The annual conservation value in terms of WTP for the preservation of the myrtle sites in Dooreh was estimated as $102,525. Among the variables of the model presented, education had a positive impact, while the amount proposed for payment and family size had a negative impact on the WTP. Conclusions： Our estimate of the value of myrtle conservation should provide justification for policy makers and decision making bodies of natural resources to implement policies in order to conserve the natural sites of this species more effectively.

Advances in Doubling Methods of Haploids by in vivo Induction in Maize

Haploid breeding can shorten the breeding process and improve the breeding efficiency. Currently, in vivo haploid induction technology has been com- monly used in maize （ Zea mays L. ）. This paper briefly introduced in vivo haploid induction technologies, summarized doubling methods of maize haploids and described the significance and application of maize haploids, which provided the basis for further development of haploid breeding in maize.

Observation of Clinical Treatment Effect of Plastic Surgery of Asymmetric Double Eyelids

Objective:To explore the clinical efficacy of plastic surgery of asymmetric double eyelid.Methods:The clinical data of 70 patients with asymmetrical double eyelid who underwent plastic surgery in our hospital from April 2018 to December 2019 were retrospectively analyzed.The patients were divided into different groups based on different plastic surgery procedures.The control group(n=35 cases)were the patients who underwent double eyelid incision method,and the patients who used embedding double eyelid method were included in the observation group(n=35 cases).The operation time,intraoperative blood loss,incision size,healing time of incision,satisfaction of p1astic surgery and occurrence of complications were compared between the two groups.Results:The operation time and incision healing time of the observation group were shorter than those of the control group.The intraoperative blood 1oss and incision were less than those of the control group,and the satisfaction was higher than that of the control group.The difference was statistically significant(P<0.05).The incidence of complications in the observation group was slightly lower than the control group,but the difference was not statistically significant(P>0.05).Conclusion:For asymmetric double eyelid,it should undergo embedding double eyelid plastic surgery,because the operation time and incision healing time are shorter.And intraoperative blood 1oss and incision size are smal1er,which can improve patient satisfaction and reduce the incidence of complications.

State space solution to 3D multilayered elastic soils based on order reduction method

Starting with the governing equations in terms of displacements of 3D elastic media, the solutions to displacement components and their first derivatives are obtained by the application of a double Fourier transform and an order reduction method based on the Cayley-Hamilton theorem. Combining the solutions and the constitutive equations which connect the displacements and stresses, the transfer matrix of a single soil layer is acquired. Then, the state space solution to multilayered elastic soils is further obtained by introducing the boundary conditions and continuity conditions between adjacent soil layers. The numerical analysis based on the present theory is carried out, and the vertical displacements of multilayered foundation with a weak and a hard underlying stratums are compared and discussed.

Theoretical study on non-sequential double ionization of carbon disulfide with different bond lengths in linearly polarizedlaser fields

By using a two-dimensional Monte-Carlo classical ensemble method, we investigate the double ionization（DI） process of the CS_2 molecule with different bond lengths in an 800-nm intense laser field. The double ionization probability presents a ＂knee＂ structure with equilibrium internuclear distance R = 2.9245 a.u.（a.u. is short for atomic unit）. As the bond length of CS increases, the DI probability is enhanced and the ＂knee＂ structure becomes less obvious. In addition,the momentum distribution of double ionized electrons is also investigated, which shows the momentum mostly distributed in the first and third quadrants with equilibrium internuclear distance R = 2.9245 a.u. As the bond length of CS increases,the electron momentum becomes evenly distributed in the four quadrants. Furthermore, the energy distributions and the corresponding trajectories of the double-ionized electrons versus time are also demonstrated, which show that the bond length of CS in the CS_2 molecule plays a key role in the DI process.

引发内蒙古汛期暴雨洪涝灾害的降水事件雨强特征分析

选取2017—2018年汛期(6—8月)内蒙古108例引发暴雨洪涝灾害的降水事件,对其雨强持续性、最大值、日变化等特征进行分析,通过双重e指数函数和百分位相结合方法,确定降水事件阈值。结果表明:(1)降水事件高发区在大兴安岭东部,最高可达5~6次,持续时间最长为10d,降水事件次高发区在阴山山脉以南;(2)降水事件雨强最大值和最小值均出现在东部地区,极差最大值达70.4mm·h^(-1),西部和中部地区雨强最大值较接近,中部地区雨强极差最小,为16.0mm·h^(-1),但降水事件平均雨强最大值出现在西部地区,最小值出现在中部地区;(3)降水事件雨强日变化特征具有地域性差异,西部地区雨强(平均雨强)最大值出现时间具有分散不集中且差异较大的特点,易出现在凌晨、早晨、中午和傍晚,中部和东部地区易出现在中午和下午;(4)西部、中部和东部地区降水事件阈值分别为13.8mm·h^(-1)、10.0mm·h^(-1)和14.2mm·h^(-1)。

Characterization of amphiphilic dendrimer modified PEG-PLA nanoparticles prepared by a double emulsion-solvent evaporation method

Drug delivery by nanocarriers requires characterizations of suitable particle size, high drug loading and safety. In this work, we prepared an amphiphilic dendrimer modified PEG-PLA mixed nanoparticles（NPs） by a double emulsion-solvent evaporation（DESE） method. The particle size and drug encapsulation efficacy（EE） were compared to evaluate and optimize the preparation parameters. The mixed NPs had average size ranging from（102±1） nm to（137±5） nm, and the zeta potential turned to positive with incorporation of the amphiphilic dendrimer. The NPs showed different EE of docetaxel（DTX） and paclitaxel（PTX） with higher affinity to more lipophilic PTX. The blank mixed NPs showed little cytotoxicity, and the DTX-loaded NPs could effectively facilitate the antiproliferation activity on PC-3 cells. The NPs could be used as an effective drug delivery system, and its anti-tumor effect is worthy of further study.

Completeness of the system of eigenvectors of off-diagonal operator matrices and its applications in elasticity theory

This paper deals with off-diagonal operator matrices and their applications in elasticity theory. Two kinds of completeness of the system of eigenvectors are proven, in terms of those of the compositions of two block operators in the off-diagonal operator matrices. Using these results, the double eigenfunction expansion method for solving upper triangular matrix differential systems is proposed. Moreover, we apply the method to the two-dimensional elasticity problem and the problem of bending of rectangular thin plates on elastic foundation.

Kinetic Characteristics of Nitrate Uptake by Wheat and Rape and Their Determination

15-day old seedlings of wheat and rape were grown in a series of solutions with different concentrations of KNO3 for a definite period of time. The changes in NO3- concentration of the solutions were determined by the double ion-selective electrode method, and then the amount of NO3- taken up by the plants was estimated and values of Km and Imax of the Michealis-Menten equation were calculated. Results show that both the method and conditions of determination affected the values of Km and Imax. For example, the Km value was appreciably reduced when the volume of culture solution was increased or when the duration of nutrient uptake was shortened; the Km value obtained with short-term depletion method was higher than that obtained with long-term one. Similar Variations were found for the values of Imax. There was a considerable difference in the characteristics of uptake kinetics between wheat and rape when determined under the same conditions of determination. The isotherm of NO3- uptake by wheat could be separated into saturated and unsaturated parts, and when the concentration of NO3- exceeded 180 uuuuuuuuuuuuM, the relationship between the rate of NO3- uptake and NO3- concentration tended to be linear. However, the isotherm of NO3- uptake by rape was found to fit the Michealis-Menten equation and no linear relationship could be found.

AN IMPROVED RECURSIVE DOUBLING ALGORITHM FOR THE PARALLEL SOLUTION OF LINEAR RECURRENCE R

An improved recursive doubling algorithm for solving linear recurrence R <n,1>is given,whose parallel time complexity is (τ++τ.) logn when n processors are available,achieving the lower bound in array processor type computation.

Double Exp-Function Method for Multisoliton Solutions of The Tzitzeica-Dodd-Bullough Equation

In this work, it is aimed to find one- and two-soliton solutions to nonlinear Tzitzeica-Dodd-Bullough （TDB） equation. Since the double exp-function method has been widely used to solve several nonlinear evolution equations in mathematical physics, we have also used it with the help of symbolic computation for solving the present equation. The method seems to be easier and more accurate thanks to the recent developments in the field of symbolic computation.

NEW PERIODIC SOLUTIONS OF NONLINEAR EVOLUTION EQUATIONS

In this paper,some new periodic solutions of nonlinear evolution equations and corresponding travelling wave solutions are obtained by using the double function method and Jacobi elliptic functions.

Optimal reduction of anthropogenic emissions for air pollution control and the retrieval of emission source from observed pollutantsⅢ:Emission source inversion using a double correction iterative method

Using the incomplete adjoint operator method in part I of this series of papers,the total emission source S can be retrieved from the pollutant concentrationsρob obtained from the air pollution monitoring network.This paper studies the problem of retrieving anthropogenic emission sources from S.Assuming that the natural source Sn is known,and as the internal source Sc due to chemical reactions is a function of pollutant concentrations,if the chemical reaction equations are complete and the parameters are accurate,Sc can be calculated directly fromρob,and then Sa can be obtained from S.However,if the chemical reaction parameters(denoted asγ)are insufficiently accurate,bothγand Sc should be corrected.This article proposes a"double correction iterative method"to retrieve Sc and correctγand proves that this iterative method converges.

An ab initio investigation of the low-lying electronic states of BeH

Potential energy curves （PECs） for the ground state （X2∑＋） and the four excited electronic states （A2∏, B2∏, C2∑＋, 4∏） of a Bell molecule are calculated using the multi-configuration reference single and double excited configuration interaction （MRCI） approach in combination with the aug-cc-pVTZ basis sets. The calculation covers the internuclear distance ranging from 0.07 nm to 0.70 nm, and the equilibrium bond length Re and the vertical excited energy Te are determined directly. It is evident that the X2∑＋, A2∏, B2∏, C2∑＋ states are bound and 4∏ is a repulsive excited state. With the potentials, all of the vibrational levels and inertial rotation constants are predicted when the rotational quantum number J is set to be equal to zero （J = 0） by numerically solving the radial SchrSdinger equation of nuclear motion. Then the spectroscopic data are obtained including the rotation coupling constant w e, the anharmonic constant WeXe, the equilibrium rotation constant Be, and the vibration-rotation coupling constant ae. These values are compared with the theoretical and experimental results currently available, showing that they are in agreement with each other.

The double auxiliary equations method and its application to space-time fractional nonlinear equations

This paper reflects the execution of a reliable technique which we proposed as a new method called the double auxiliary equations method for constructing new traveling wave solutions of nonlinear fractional differential equation.The proposed scheme has been successfully applied on two very important evolution equations,the space-time fractional differential equation governing wave propagation in low-pass electrical transmission lines equation and the time fractional Burger’s equation.The obtained results show that the proposed method is more powerful,promising and convenient for solving nonlinear fractional differential equations(NFPDEs).To our knowledge,the solutions obtained by the proposed method have not been reported in former literature.