Special Lectures : SOME NEW AND NOTEWORTHY SPECIES OF AGARICALES FROM SOUTHERN AND SOUTHEASTERN YUNNAN , CHINA AND THEIR GEOGRAPHIC DISTRIBUTION

( Pei Gui Liu ) 한국균학회 1993 KOREA CHINA JOINT SEMINER Vol.- No.-

Dynamic reliability of structures: the example of multi-grid composite walls

Liu, Pei,Yaoa, Qian-Feng Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.36 No.4

Based on damage accumulation of multi-grid composite walls, a method of dynamic reliability estimations is proposed. The multi-grid composite wall is composed of edge frame beam, edge frame columns, grid beams, grid columns and filling blocks. The equations including stiffness, shear forces at filling blocks cracking and multi-grid composite walls yielding, ultimate displacement, and damage index are obtained through tests of 13 multi-grid composite wall specimens. Employing these equations in reliability calculations, procedures of dynamic reliability estimations based on damage accumulation of multi-grid composite walls subjected to random earthquake excitations are proposed. Finally the proposed method is applied to the typical composite wall specimen subjected to random earthquake excitations which can be specified by a finite number of input random variables. The dynamic reliability estimates, when filling blocks crack under earthquakes corresponding to 63% exceedance in 50 years and when the composite wall reach limit state under earthquakes corresponding to 2-3% exceedance in 50 years, are obtained using the proposed method by taking damage indexes as thresholds. The results from the proposed method which show good agreement with those from Monte-Carlo simulations demonstrate the proposed method is effective.

A reliability-based fragility assessment method for seismic pounding between nonlinear buildings

Pei Liu,Hai-Xin Zhu,Peng-Peng Fan,Wei Guo Yang 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.1

Existing methods to estimate the probability of seismic pounding occurrence of adjacent buildings do not account for nonlinear behavior or only apply to simple lumped mass systems. The present study proposes an efficient method based on subset simulation for fragility and risk assessment of seismic pounding occurrence between nonlinear adjacent buildings neglecting pounding effects with application to finite element models. The proposed method is first applied to adjacent buildings modeled as elastoplastic systems with substantially different dynamic properties for different structural parameters. Seismic pounding fragility and risk of adjacent frame structures with different floor levels is then assessed, paying special attention to modeling the non-linear material behavior in finite element models. Difference in natural periods and impact location are identified to affect the pounding fragility simultaneously. The reliability levels of the minimum code-specified separation distances are also determined. In addition, the incremental dynamic analysis method is extended to assess seismic pounding fragility of the adjacent frame structures, resulting in higher fragility estimates for separation distances larger than the minimum code-specified ones in comparison with the proposed method.

Seismic fragility analysis of sliding artifacts in nonlinear artifact-showcase-museum systems

Pei Liu,Zhi-Hao Li,Wei-Guo Yang 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.3

Motivated by the demand of seismic protection of museum collections and development of performance-based seismic design guidelines, this paper investigates the seismic fragility of sliding artifacts based on incremental dynamic analysis and three-dimensional finite element model of the artifact-showcase-museum system considering nonlinear behavior of the structure and contact interfaces. Different intensity measures (IMs) for seismic fragility assessment of sliding artifacts are compared. The fragility curves of the sliding artifacts in both freestanding and restrained showcases placed on different floors of a four-story reinforced concrete frame structure are developed. The seismic sliding fragility of the artifacts within a real-world museum subjected to bi-directional horizontal ground motions is also assessed using the proposed IM and engineering demand parameter. Results show that the peak floor acceleration including only values initiating sliding is an efficient IM. Moreover, the sliding fragility estimate for the artifact in the restrained showcase increases as the floor level goes higher, while it may not be true in the freestanding showcase. Furthermore, the artifact is more prone to sliding failure in the restrained showcase than the freestanding showcase. In addition, the artifact has slightly worse sliding performance subjected to bi-directional motions than major-component motions.

Continuous supply of recycled Pacific oceanic materials in the source of Cenozoic basalts in SE China: the Zhejiang case

Liu, Shao-Chen,Xia, Qun-Ke,Choi, Sung Hi,Deloule, Etienne,Li, Pei,Liu, Jia Springer-Verlag 2016 Contributions to mineralogy and petrology Vol.171 No.12

<P>Various enriched recycled oceanic components in the source of Cenozoic intra-plate alkaline basalts from eastern China were identified by previous studies. Due to the existence of a stagnant subducted Pacific slab in the mantle transition zone beneath eastern China, it is logical to connect the stagnant slab to the recycled oceanic materials. However, the recycled oceanic materials could also result from ancient subduction events (e.g., Paleo-Tethyan, Paleo-Asian or Izanagi plate subduction) because enriched geochemical signatures of a recycled slab can be preserved in the mantle for longer than 1 Gyr. Investigating the temporal variations of the recycled oceanic materials in the mantle source is a useful way to trace the origin of the basalts. In this article, we have conducted a detailed geochemical study, including major and trace elements and Sr-Nd-Pb isotopes, on two alkaline basalt groups from Zhejiang, SE China, which erupted 26-17 Ma and after 11 Ma, respectively. In particular, we recovered the H2O content of the initial magmas based on the H2O content of the clinopyroxene (cpx) phenocrysts and the partition coefficients of H2O between cpx and basaltic melts. The H2O contents of the Zhejiang basalts range from 1.3 to 2.6 (wt.%), which fall within the range of back-arc basin or island arc basalts. The older basalts are more alkaline and have lower Si and Al contents; higher trace element concentrations; higher La/Yb, Ce/Pb and Nb/La ratios; lower H2O/Ce and Ba/Th ratios; and stronger negative K, Pb, Hf and Ti anomalies than the younger ones. The co-relationships between Ba/La, H2O/Ce, Nb/La, Ce/Pb and Ba/Th in the two groups of the Zhejiang basalts indicate that a recycled dehydrated oceanic alkaline basalt component is needed in the source of the older rocks, along with a depleted mantle component. Meanwhile, an additional recycled dehydrated sediment component was required in the source of the younger rocks. The temporal change in the recycled oceanic materials in the mantle sources of Zhejiang Cenozoic basalts demonstrates that the recycled components can only originate in the stagnant Pacific slab that is the only plate subducted since 100 Ma in this area.</P>

Enhanced Morris for the extraction of significant parameters in high-dimensional design optimization

Pei Yuan,Jin Cheng,Zhenyu Liu,Daxin Liu,Jianrong Tan 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.11

The traditional Morris method cannot ensure the consistent extraction of significant parameters because its random sampling strategy often leads to an improper coverage of the input space, especially when the number of sample points is small. To overcome the drawbacks, we developed an improved sampling strategy to enhance the performance of Morris method based on Latin hypercube sampling (LHS) with the idea of Central composite design (CCD) and a fluctuant step to generate a more uniform points set. A comparison on the results of a numerical example obtained by the enhanced Morris, the traditional methods and CCS-Morris demonstrated that the former had a much better performance. The application of the enhanced Morris method in the high-dimensional optimization of a compressor shell with 15 design parameters aimed at increasing its natural frequencies and keeping its mass relatively light demonstrates that the method is effective and applicable in engineering design.

Elastography for Breast Cancer Diagnosis: a Useful Tool for Small and BI-RADS 4 Lesions

Liu, Xue-Jing,Zhu, Ying,Liu, Pei-Fang,Xu, Yi-Lin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.24

The present study aimed at evaluating and comparing the diagnostic performance of B-mode ultrasound (US), elastography score (ES), and strain ratio (SR) for the differentiation of breast lesions. This retrospective study enrolled 431 lesions from 417 in-hospital patients. All patients were examined with both conventional ultrasound and elastography. Two experienced radiologists reviewed ultrasound and elasticity images. The histopathologic result obtained from ultrasound-guided core biopsy or operation excisions were used as the reference standard. Pathologic examination revealed 276 malignant lesions (64%) and 155 benign lesions (36%). A cut-off point of 4.15 (area under the curve, 0.891) allowed significant differentiation of malignant and benign lesions. ROC (receiver-operating characteristic) curves showed a higher value for combination of B-mode ultrasound and elastography for the diagnosis of breast lesions. Conventional ultrasound combined elastography showed high sensitivity, specificity, and accuracy for group II lesions (10mm<lesion diameter ${\leq}20mm$). Elastography combined with conventional ultrasound show high specificity and accuracy for differentiation of benign and malignant breast lesions. Elastography is particularly important for the diagnosis of BI-RADS 4 and small breast lesions.

Analysis of Mammographic Breast Density in a Group of Screening Chinese Women and Breast Cancer Patients

Liu, Jing,Liu, Pei-Fang,Li, Jun-Nan,Qing, Chun,Ji, Yu,Hao, Xi-Shan,Zhang, Xue-Ning Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.15

Background: A dense breast not only reduces the sensitivity of mammography but also is a moderate independent risk factor for breast cancer. The percentage of Western women with fat breast tissue is higher aged 40 years or older. To a certain extent, mammography as a first choice of screening imaging method for Western women of this group is reasonable. Hitherto, the frequency and age distribution of mammographic breast density patterns among Chinese women had not been characterized. The purpose of this study was to investigate the frequency and age distribution of mammographic breast density patterns among a group of Chinese screening women and breast cancer patients in order to provide useful information for age-specific guidelines for breast cancer screening in Chinese women. Methods: A retrospective review of a total of 3,394 screening women between August and December 2009 and 2,527 breast cancer patients between July 2011 and June 2012 was conducted. Descriptive analyses were used to examine the association between age and breast density. The significance of differences of breast density between the screening women and the breast cancer patients was examined using nonparametric tests. Results: There was a significant inverse relationship between age and breast density overall (r=-0.37, p< 0.01). Breast density of the breast cancer patients in the subgroups of 40-49 years old was greater compared with that of the screening women, the same in those aged 50-54 years and in those 55 years old or older, less than in the screening group. Conclusions: With regard to the Chinese women younger than 55 years old, the diagnostic efficiency of breast cancer screening imaging examinations may be potentially improved by combining screening mammography with ultrasound.

The Association between Obesity and Asthma in Children-A Systemic Literature Review

Pei-Ching Liu,Bih-Shy,Gau 한국간호과학회 2009 한국간호과학회 학술대회 Vol.2009 No.10

Perception of Stress and Depression in Patients with Hemodialysis

Liu, Pei Ling,Sheu, Shu Lian 한국간호과학회 2009 한국간호과학회 학술대회 Vol.2009 No.10