Quasi-In-Situ Analysis of As-Rolled Microstructure of Magnesium Alloys during Annealing and Subsequent Plastic Deformation.

In this paper, quasi-in situ experiments were carried out on rolled AZ31 magnesium alloy sheets to track the recrystallization behavior of the rolled microstructure during the heat treatment process and the plastic deformation behavior during the stretching process. The as-rolled microstructures are classified into five characteristics and their plastic deformation behaviors are described. The research shows that annealing recrystallization leads to grain reorganization, resulting in the diversity of grain orientation, and it is easier to activate basal slip.

Enhanced Formability of Magnesium Alloy Rolled Plates by 101¯2 Tensile Twinning and Recrystallization.

To solve the problem of poor formability of magnesium alloys, the bending and straightening process was used to successfully introduce large-volume 101¯2 tensile twins and dynamic recrystallization into the plates, and the comprehensive mechanical properties of the plates were improved, in which the anisotropy index (Lankford value: r¯) decreased by 77%, and the corresponding Erishen value (IE) increased by 88%. The research shows that most of the continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX) inherit the grain orientation of the parent grains, and a few have deviations from the parent grains. The twinning-assisted dynamic recrystallization (TDRX) can effectively inherit the grain orientation of the parent grain and retain the orientation relationship of the 101¯2 tensile twin.

Effect of Temperature Field and Stress Field of Different Crack Behavior on Twins and Dislocations under Mg Alloy Rolling.

Aiming at the problem of the poor plasticity of magnesium alloy leading to serious edge cracks in the rolling process, this paper conducts a systematic study on the crack suppression mechanism of rolling under different thickness reductions. Using restricted rolling and conventional rolling, comparing the microstructure evolution of the plate after rolling, and combining the information of the simulated temperature field and stress field of the plates, the behavior of twins and dislocations under different thickness reductions is explained, and the influence of serious damage caused by single-pass hot rolling of magnesium alloy is explored. The compressive stress fields along with the transverse and normal directions under restricted rolling cause the compression twins to mature into secondary twins under rolling with small thickness reduction and induce a large number of tensile twins when the thickness reduction amount is increased.

Enhanced acoustic mode coupling resulting from an internal solitary wave approaching the shelfbreak in the South China Sea.

Internal waves and bathymetric variation create time- and space-dependent alterations in the ocean acoustic waveguide, and cause subsequent coupling of acoustic energy between propagating normal modes. In this paper, the criterion for adiabatic invariance is extended to the case of an internal solitary wave (ISW) encountering a sloping bathymetry (i.e.

Prevalence of human immunodeficiency virus and its association with hepatitis B, C, and D virus infections among incarcerated male substance abusers in Taiwan.

Taiwan has been facing a rising epidemic of human immunodeficiency virus (HIV) infection since 2004. Injection drug users comprised 38.5% of accumulated HIV cases by 2007.

Prevalence of heroin and methamphetamine male users in the northern Taiwan, 1999-2002: capture-recapture estimates.

Background: Illegal drug use and related problems have been emerging as an important public health issue in Taiwan. Via the capture-recapture approach, the present study aimed to offer insights into the size of heroin and methamphetamine male user population in the northern Taiwan during the period from 1999 to 2002.

Methods: Annual lists of male subjects were collated from both judiciary and medical systems in Taoyuan County, Taiwan.

Gender difference in the clinical and behavioral characteristics of human immunodeficiency virus-infected injection drug users in Taiwan.

Background/purpose: Injection drug users (IDUs) have become the major contributors to the human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome epidemic in Taiwan, accounting for more than 60% of new cases in 2005. In Taiwan, gender difference in risk factors for HIV among IDUs has not been reported before. We studied the clinical and sociodemographic characteristics, sexual behaviors, drug use histories and criminal records of male and female HIV-infected IDUs.

Psychiatric comorbidity and gender difference among treatment-seeking heroin abusers in Taiwan.

The objectives of the present study were to estimate the psychiatric comorbidity of Taiwanese heroin users seeking treatment and to identify the gender differences in psychiatric comorbidity and drug use behavior. Subjects were interviewed using a structured questionnaire on drug use behavior and the Mini International Neuropsychiatric Interview for psychiatric disorders. Of the subjects, 58.