Radiation of a TM mode from an open end of a three-layer dielectric capillary

Modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently proposed to reduce radiation divergence being a representative example [Opt. Lett. 45 5416(2020)]. We present a rigorous approach that allows for an analytical description of the electromagnetic processes that occur when the structure is excited by a single waveguide TM mode. In other words, the corresponding canonical waveguide diffraction problem is solved in a rigorous formulation. This is a continuation of our previous papers which considered simpler cases with a homogeneous or two-layer dielectric filling. Here we use the same analytical approach based on the Wiener–Hopf–Fock technique and deal with the more complicated case of a three-layer dielectric lining. Using the obtained rigorous solution, we discuss the possibility of manipulating the far-field radiation pattern using a third layer made of a low permittivity material.

Effect of joints on microwave fracturing of the Bukit Timah granite using an open-ended antenna

Microwave fracturing of rocks before mechanical breakage could improve the performance of mechanical excavators and reduce environmental impacts.Previous research focused on the microwave fracturing of intact rock blocks.By using an open-ended antenna,this paper investigates the effect of pre-existing joints on the microwave fracturing of the Singapore Bukit Timah granite blocks.The results show that the specimens are weakened in the manners of cracking,spalling,melting,or a combination of them.The crack number and the total crack length produced by microwave treatment of jointed rock blocks are slightly smaller than those in the intact rock blocks.The interaction between joints and microwave-induced cracks can be summarized into the following four patterns:(1)microwave-induced cracks become arrested so that the crack propagation is terminated;(2)microwave-induced cracks penetrate the joints and continue to propagate;(3)microwave-induced cracks become deflected along the joints;and(4)microwave-induced cracks propagate forward following the joints.The smaller the approach angle between the microwave-induced crack and the preexisting joint is,the more microwave-induced cracks tend to be arrested at the joint.Increasing the approach angle between the microwave-induced crack and the joint can increase the chance of microwave-induced crack penetrating the joint.The results also show that the smaller the distance is between the microwave radiation point and the joint,the easier it is for microwave-induced cracks to penetrate the joints;otherwise,the microwave-induced crack is more likely to be arrested at the pre-existing joint.

Study on the squeezing effect of open-ended pipe piles

During the installation of a pipe pile,the soil around the pile will be squeezed out. This paper deals with this squeezing effect of open-ended pipe piles using the cylindrical cavity expansion theory. The characteristics of soil with different tension and compression moduli and dilation are involved by applying the elastic theory with different moduli and logarithmic strain. The closed-form solutions of the radius of the plastic region,the displacement of the boundary between the plastic region and the elastic region and the expansion pressure on the external surface of the pipe piles are obtained. When obtaining these solutions,the soil plug in the open-ended pipe pile is considered by employing an incremental filling ratio to quantify the degree of soil plugging. Moreover,the effects of the ratio of tension and compression moduli,angle of dilation and incremental filling ratio on the radius of the plastic region and the expansion pressure on the external surface of the pipe pile are investigated. The parametric analyses show that it is necessary and important to consider the difference between the tension modulus and compression modulus,dilation angle and incremental filling ratio for studying the squeezing effect of open-ended pipe pile installation. It is concluded that the analytical solutions presented in this paper are suitable for studying the squeezing effect of open-ended pipe piles.

Reform and Practice of an Engineering Postgraduate Training Pattern in an Open-Ended Base:Taking Foshan Base as an Example

The flawed engineering practice is considered the main factor that is affecting to the development quality of engineering postgraduates.Taking Foshan Base as an example,this paper has analyzed the operational pattern,practice teaching model,and internal governance system of the open-ended base as a new system for engineering practice and proposed several suggestions for the reformation of engineering postgraduates based on the construction effect.

An Assembly Coastal Building Technique in Port Engineering

The assembly coastal building technique initiated at home and abroad,is for a novel vertical standing harbor structure.Its main concept is the assembling components which can be combined and locked together to form a large caisson.Its application and future are discussed for a building.After many years of application and tests,the technique has a high stability,a wide range of application,low workload and fast construction speed.It can be widely applied in future for harbor engineering projects.

MEASUREMENT OF THE DIELECTRIC PROPERTIES OF BIOLOGICAL TISSUE

An open-ended coaxial line reflection method especially suitable for meas-uring the dielectric properties of biological tissue in vivo is described.This method offersthe advantage of not requiring any special preparation of the samples to be measured but aclose contact with the open end of a coaxial line.It is,therefore,very convenient to acquirea large number of measurement data in broad band rapidly.The method may also be usedto measure the properties of other substances.The measuring system consists of a networkanalyzer controlled by a microcomputer and calibrated by using ANA procedure to elimi-hate the influnce of error network introduced by the adapter,some connectors,etc.In or-der to reach higher accuracy,the iterative method is used to determine the parameters ofthe equivalent circuit.Measurements of permeativities of some living tissues have been per-formed in the frequency band of 0.5-2GHz.Compared with the results known in somepapers,the validity of this method has been confirmed.The difference in dielectric proper-ties between living and dead tissues,and the tissue permeativites(ε)versus frequency andduration of measurement after death have also been measured.

谈日语二外教学的探求

提出在日语二外教学中采用（Open-ended）化型教学方式，加强情感交流，建立和谐融洽的师生关系，注重文化知识的导入。充分利用语言优势，培养出符合社会对“双语”人才的需求。

You Need to Know More to Understand My Scoring on the Survey: Free-Text Comments as Part of a PROM-Survey of Men with Prostate Cancer

Prostate cancer and its treatment have long-term implications for men’s lives. We aimed to describe the content, extent, and frequency of written comments to the open-ended question, “Further comments?” in the patient-reported outcome measures questionnaire. During the study period, 897 men participated;372 wrote 747 free-text comments in the questionnaire. These comments were analysed using qualitative content analysis and were grouped into four categories: 1) prostate cancer’s influence on health;2) clarifications of answers to the survey;3) descriptions of well-being despite the cancer;and 4) experiences of care and the need for contact with health care. The distribution of the comments shifted over time. The open-ended question not only allowed the participants to explain their other responses and describe important aspects of their lives during and after treatment, something not normally covered by a questionnaire, but it also indicated their experiences of health care services along the patients’ PC-trajectory. This further raises the issue of including an open-ended item in a forced-choice survey into the ethical realm to ensure that proper care is taken of participants’ answers and thoughts.

Design and analyses of open-ended pipe piles in cohesionless soils

Large open-ended pipe pile has been found to be advantageous for use in transportation projects. The current design method, however, is not adequately developed. To close this practice gap, this paper first summarized different design methods for open-ended pipe piles in sandy soils. A major factor for all the design codes is to properly account for the formation and effects of soil plug. The comparison indicates that there is a large variation in the base capacity evaluation among different methods due to the complex behaviors of soil plug. To close the knowledge gap, discrete element method （DEM） was used to simulate the soil plugging process and provide insight on the plugging mechanism. The simulation results show that the arching effect significantly increases the internal unit shear resistance along pipe piles. The porosity distribution and particle contact force distribution from DEM model indicate a large stress concentration occurs at the bottom of the soil plug. Besides, nearly 90% of the plug resistance is provided by the bottom half portion of the soil column. The soil-pile friction coefficient has a significant effect on the magnitude of plug resistance, with the major transition occurred for friction coefficient between 0.3 and 0.4.

Effects of inner sleeves on the inner frictional resistance of open-ended piles driven into sand

In open-ended piles, inner friction is developed between inner pile shaf and the inner soil. Inner frictional resistance depends largely on the degree of soil plugging, which is influenced by many factors including pile diameter, relative density and end conditions of piles. In this paper, effects of inner sleeves on inner frictional resistance are discussed. The experiments were conducted on a medium-dense sandy ground using laboratory-scale piles. It was observed that the piles penetrated under partially-plugged or unplugged state. The results suggest that inner fiictional resistance, Qin increases with sleeve height, l linearly and requires 2D （D is pile outer diameter） of l to produce a large as 50% of Qt by Qin （Qt is total resistance）. The results also indicate that bearing capacity increases with wall thickness at the pile tip, which can be attributed to the increase in annular area. The results also indicate that soil plug height is independent of sleeve height. The results also reveal that the penetration of straight piles is closer to unplugged state than the sleeved piles. The results of incremental filling ratio and plug length ratio also indicate that the degree of soil plugging is affected by the sleeve height.

Control of Heterometallic Three-Dimensional Macrocycles with Aromatic Stacks in Tunable Host Cavities

Using coinage metal （Cu（Ⅱ）, Ag（Ⅰ）） hinges, two sets of heterometallic molecular capsules with analogous open-ended cavities were prepared based on the half-sandwich rhodium fragments. In the case of [Rh4Cu4] cages, up to six-fold-stacked host-guest structures were formed by varying the cavity＇s dimensions. Moreover, the series of capsules were demonstrated to self-fine-tune to form multi-heteroguest arrays via favourable donor-acceptor interactions and Ag-π interactions, as evidenced from single-crystal X-ray analysis.

Preparation of very long and open aligned carbon nanotubes

Very long and open aligned carbon nanotubes that reach about 2 mm long, an order of magnitude longer than previously reached, have been prepared by chemical vapor deposition over silica dioxide substrates on the surface, where iron/silica nano-composite particles are evenly positioned. The nanotubes are naturally opened at the bottom ends. The growth mechanism of the very long and open-ended nanotubes is also discussed.

Permittivity models for determination of moisture content in Hevea Rubber Latex

The commercial open-ended coaxial probe(Agilent 85070E)is the most commonly used sensor to determine the permittivity of wet materials.This paper extends the usability and applicability of the sensor to the estimation of moisture content in Hevea Rubber Latex.The dielectric constant and loss factor were measured using the commercial probe whilst the moisture contents were obtained using the standard oven drying method.Comparison results were obtained between the different dielectric models to predict moisture content in latex.Both the dielectric constant and the loss factor of rubber latex linearly increased with moisture content at all selected frequencies.Calibration equations were established to relate both the dielectric constant and the loss factor with moisture content.These equations were used to predict moisture content in Hevea latex from measured values of the dielectric constant and the loss factor.The lowest mean relative error between actual and predicted moisture contents was 0.02 at 1 GHz when using the Cole-Cole dielectric constant calibration equation.

Li Ang＇s Gendered Dissent in ＂The Devil in a Chastity Belt＂

Through a close reading, this article explores a few aspects of gendered dissent in Li Ang＇s story, ＂The Devil in a Chastity Belt,＂ which reveals the ambivalence and irony of a woman＇s participation in the Taiwan Residents opposition movement. Instead of writing a stereotypical work of political fiction for the opposition movement that she supports, Li Ang interrogates the problematic intersection of gender and politics, while reclaiming some of the neglected aspects of oppositional history. While recognizing the inevitability of historical contingency, she nevertheless questions the politically-motivated choice of asceticism, heroism, and sacrifice over individual and familial well-being. Li juxtaposes seemingly trivial and disorderly details of ordinary life against the apparently important and grandiose arena of national politics, creating tension through their interaction and contention. She employs images--including the Devil, the female body, and sensory feelings--to perform gendered dissent. While the lyrical and trivial discourse gradually disrupts the political and didactic, the story＇s open-ended conclusion inspires complex interpretations of the enigmatic symbol： the Devil wearing a chastity belt.