Performances of Concrete Columns with Modular UHPC Permanent Formworks Under Axial Load

Yibo Yang,Baixi Chen,Yong Chen,Huanyang Zhou,Fucai Liu,Xiangming Xie,Junsheng Chen,Wenying Guo,Hengchang Wang 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.5

This research proposed the modular prefabricated permanent formwork system made of ultra-high-performance concrete (UHPC). Two kinds of modular formwork shapes were designed: the flat formwork and the ribbed. The experimental investigation on the axial compression performance of the composite columns that consist of the normal strength concrete (NSC) core and the modular UHPC permanent formwork was demonstrated. Compared with the flat formwork, the ribbed formwork exhibited better bonding with the NSC core. As observed from the test results, the composite column with the ribbed formwork presented a similar axial behavior as the NSC column with a slight improvement in ultimate loads. Therefore, the modular UHPC ribbed permanent formwork could be regarded as the additional cover to the conventional NSC column. In addition, the finite element analysis (FEA) model was also developed to simulate the composite columns numerically. The predicted capacities agreed with the experimental results, which validated the numerical models. The crack pattern estimated by the FEA model revealed that the interaction between the permanent formwork and the inner concrete introduced many tiny cracks to the concrete core. However, as protected by the UHPC permanent formwork, the overall durability of the composite columns can still be enhanced.

Utilization of Completely Recycled Fine Aggregate for Preparation of Lightweight Concrete Partition Panels

Yibo Yang,Baixi Chen,Weizhen Zeng,Yanjun Li,Qiaohui Chen,Wenying Guo,Hengchang Wang,Yingqin Chen 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.5

To reduce the cost of lightweight concrete (LWC) partition panels and to address recycling concrete waste, this work utilized completely recycled fine aggregate (CRFA) to replace the natural fine aggregate and ceramsite in the preparation of LWC and LWC partition panels. To this end, an autoclave-free curing process and an air-entraining agent were used to prepare the CRFA-LWC. The workability, compressive strength, drying shrinkage, and pore structure of the CRFA-LWC and the performance of the CRFA-LWC partition panels were then investigated. The results show that the optimal ratio of the CRFA to the cement is 2.2 for the lightweight concrete, and the optimal panel cross section is a rounded rectangular one. All the pores in the CRFA-LWC have a diameter of smaller than 0.17 mm, and the diameter of 89% of them is less than 0.05 mm. In order to satisfy the drying shrinkage requirements stipulated by Chinese code JC/T 169-2016, the CRFA-LWC should be cured for at least 10 days. The economic analysis concludes that the material cost of CRFA-LWC is 40% lower than that of the autoclaved ceramsite concrete. In addition, utilizing CRFA in lightweight concrete can ease the shortage of natural aggregate.

Abnormal Event Detection in Nature Settings

Yang Liu,Yibo Li,Xiaofei Ji 보안공학연구지원센터(IJSIP) 2014 International Journal of Signal Processing, Image Vol.7 No.4

Low-Complexity Signal Vector Based Detection Algorithm for Spatial Modulation

Yang Jiang,Jiejun Wen,Yuanlu Wang,Yibo Li 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.2

In this paper, signal vector based detection (SVD) algorithm for spatial modulation (SM) is modified to achieve a near maximum-likelihood (ML) performance and reduces the complexity compared to ML. First, the proposed low-complexity SVD (LC-SVD) algorithm orders the antenna index list based on the angle between the received vector y and the channel vector j h , and then it estimates symbol by compensating the channel attenuation with transmitting antenna index list. We can trade-off between the performance and the complexity by changing the number of the candidate transmitting antennas. The theoretical analysis and simulation results show that the LC-SVD algorithm can achieve a near-ML performance with lower complexity.

Antiviral Potential of the Genus Panax: An updated review on their effects and underlying mechanism of action

Yibo Zhang,Xuanlei Zhong,Zhichao Xi,Yang Li,Hongxi Xu The Korean Society of Ginseng 2023 Journal of Ginseng Research Vol.47 No.2

Viral infections are known as one of the major factors causing death. Ginseng is a medicinal plant that demonstrated a wide range of antiviral potential, and saponins are the major bioactive ingredients in the genus Panax with vast therapeutic potential. Studies focusing on the antiviral activity of the genus Panax plant-derived agents (extracts and saponins) and their mechanisms were identified and summarized, including contributions mainly from January 2016 until January 2022. P. ginseng, P. notoginseng, and P. quinquefolius were included in the review as valuable medicinal herbs against infections with 14 types of viruses. Reports from 9 extracts and 12 bioactive saponins were included, with 6 types of protopanaxadiol (PPD) ginsenosides and 6 types of protopanaxatriol (PPT) ginsenosides. The mechanisms mainly involved the inhibition of viral attachment and replication, the modulation of immune response by regulating signaling pathways, including the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, cystathionine γ-lyase (CSE)/hydrogen sulfide (H₂S) pathway, phosphoinositide-dependent kinase-1 (PDK1)/ protein kinase B (Akt) signaling pathway, c-Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) pathway, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. This review includes detailed information about the mentioned antiviral effects of the genus Panax extracts and saponins in vitro and in vivo, and in human clinical trials, which provides a scientific basis for ginseng as an adjunctive therapeutic drug or nutraceutical.

Effect of six carbohydrate sources on the longevity of a whitefly parasitoid Eretmocerus hayati (Hymenoptera: Aphelinidae)

Yibo Zhang,Nianwan Yang,JinjunWang,FanghaoWan 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.4

Parasitoid adults often acquire carbohydrates by feeding on floral nectar and honeydew which provides themwith energy and prolongs their life span. The concentration and type of saccharide in nectar and honeydew arevariable by species of plant and insect. To explore the effects of various sugar type and concentrations on parasitoidfitness, we compared 5%, 10% and 20% (w/v) solutions of six different sugar resources (glucose, fructose,sucrose, trehalose, melezitose and honey) on the longevity of Eretmocerus hayati, a larval parasitoid of thewhiteflyBemisia tabaci in China. Male and female longevity was increased by all of the sugar diets, but female waspssurvived longer than the males when the same sugar diet was supplied. Female parasitoids feeding on 10%glucose and 10% honey increased longevity, respectively up to 6.2- and 5.9-fold longer than distil water; 5%honey and 10% fructose had the greatest effects on male longevity, up to 3.5- and 3.3-fold. All six sugar diets,no matter which concentration, significantly changed the survival curves. Glucose, sucrose and honey wereoptimal sugar diets for this wasp, and 10% was the optimal concentration. Our results could provide an insightinto the nutritional requirements of E. hayati under laboratory conditions. Such information can be a basis toimprove the longevity of this biological control agent by sugar feeding during the indoor mass-rearing process.

A rolling analysis on the prediction of value at risk with multivariate GARCH and copula

Bai, Yang,Dang, Yibo,Park, Cheolwoo,Lee, Taewook The Korean Statistical Society 2018 Communications for statistical applications and me Vol.25 No.6

Risk management has been a crucial part of the daily operations of the financial industry over the past two decades. Value at Risk (VaR), a quantitative measure introduced by JP Morgan in 1995, is the most popular and simplest quantitative measure of risk. VaR has been widely applied to the risk evaluation over all types of financial activities, including portfolio management and asset allocation. This paper uses the implementations of multivariate GARCH models and copula methods to illustrate the performance of a one-day-ahead VaR prediction modeling process for high-dimensional portfolios. Many factors, such as the interaction among included assets, are included in the modeling process. Additionally, empirical data analyses and backtesting results are demonstrated through a rolling analysis, which help capture the instability of parameter estimates. We find that our way of modeling is relatively robust and flexible.

Analysis of the Operating Principle and Parameter Design for the Modular Multilevel DC/DC Converter

Binbin Li,Shaolei Shi,Yibo Zhang,Rongfeng Yang,Gaolin Wang,Dianguo Xu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The modular multilevel converter (MMC) has become more and more attractive in the field of high-voltage high-power dc/ac power conversions. In the very recent years, the dc/dc modular multilevel converter is proposed intended for high-voltage dc/dc applications, such as the solid-state transformers and future dc-grid networks, which is extended from the traditional MMC. However, it remains unknown how to optimize the operation of this dc/dc modular multilevel converter and how to dimension the parameters of the elements in it. In this paper, a detailed analysis is performed to indentify the operating principle of the dc/dc modular multilevel converter. Using these analyses, the selection rules and parameter design method of the components are given to maximize the utilization ratio, improve the power density, and increase efficiency. Finally, the validity and effectiveness of this paper are verified by simulation results.

Modeling and analysis of a rotational piezoelectric energy harvester with limiters

Xiaobo Rui,Zhoumo Zeng,Yibo Li,Yu Zhang,Zi Yang,Xinjing Huang,Zhou Sha 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

A rotational piezoelectric energy harvester has the ability to convert rotation mechanical energy into electric power. The piezoelectric harvester with cantilever based on gravity excitation has received great attention. Given that gravity excitation is greater than conventional vibration excitation, and large mass are often used in low-frequency applications, large amplitudes pose a significant threat to the life of a harvester. In this study, a rotational energy harvester with limiters is investigated to promote practical development. This study establishes a theoretical model verified by experiments. Results show that stiffness has little influence on the limiting effect. In the experimental conditions, the output after 2000 N/m is basically the same. The peak value of the output voltage is linearly proportional to the space. Given that an impact excitation is generated in the collision, the limiter widens the frequency band of the output in the upsweep.

Accumulation characteristics and correlation analysis of five ginsenosides with different cultivation ages from different regions

Dan Xiao,Hao Yue,Yang Xiu,Xiuli Sun,YiBo Wang,Shuying Liu 고려인삼학회 2015 Journal of Ginseng Research Vol.39 No.4

Background: Ginseng (the roots of Panax ginseng Meyer) is a well-known traditional Oriental medicine and is now widely used as a health food. It contains several types of ginsenosides, which are considered the major active medicinal components of ginseng. It has recently been reported that the qualitative and quantitative properties of ginsenosides found in ginseng may differ, depending on cultivation regions, ages, species, and so on. Therefore, it is necessary to study these variations with respect to cultivation ages and regions. Methods: In this study, 3e6-yr-old roots of P. ginseng were collected from three different cultivation regions. The contents of five ginsenosides (Rb1, Rd, Rc, Re, and Rgl) were measured by rapid resolution liquid chromatography coupled with quadrupleetime-of-flight mass spectrometry. The KruskaleWallis Rank sum test and multiple t test were used for comparative analysis of the data to evaluate the dynamic changes in the accumulation of these ginsenosides affected by cultivation regions and ages. Results: The content and composition of ginsenosides varied significantly among specimens collected from different cultivation regions and having different cultivation ages. For all samples, the content of Rg1 and Re ginsenosides increases with age and this rate of increase is different for each sample. The contents of Rb1, Rc, and Rd varied with cultivation ages in samples from different cultivation regions; especially, Rb1 from a 6-yr-old root showed approximately twofold variation among the samples from three cultivation regions. Furthermore, the content of Rb1 highly correlated with that of Rd (r ¼ 0.89 across all locations and ages). Conclusion: In our study, only the contents of ginsenosides Rg1 and Re were affected by the root age. Ginsenosides Rb1, Rc, and Rd varied widely with ages in samples from different cultivation regions.