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Construction of optimal designs for quantile regression model via particle swarm optimization
Zhai Yi,Xing Chen,Fang Zhide 한국통계학회 2023 Journal of the Korean Statistical Society Vol.52 No.4
As an extension of mean regression and being robust against outliers, quantile regression has been used in many fields such as biomedicine, ecology, economics. However, it is theoretically and computationally challenging to find the optimal experimental design for quantile regression due to the complexity of the optimiza- tion problem. The purpose of this paper is to provide theoretical necessary conditions for A- and c-optimality of a design separately, and a numerical algorithm to find optimal designs for quantile regression models. The algorithm is constructed through particle swarm optimization so as to solve the problem of non-convexity of optimality criteria. In this paper, the algorithm is applied to obtain locally as well as Bayesian optimal designs for Michaelis–Menten, Emax and Exponential quantile regression models. We demonstrate that this technique can be applied to a variety of optimality criteria and scale functions without making any further assumption.
Impact of high-temperature-water cooling damage on the mechanical properties of concrete
Zhai, Yue,Li, Yan,Li, Yubai,Wang, Siwei,Liu, Yi,Song, Ki-Il Elsevier 2019 Construction & building materials Vol.215 No.-
<P><B>Abstract</B></P> <P>A series of impact tests were conducted on split Hopkinson pressure bar equipment to study the influence of high-temperature-cooling damage on the mechanical properties of concrete. The experimental investigation showed the influence on the peak stress, peak strain, and fracture mode. The results indicate that the strain rate is directly related to the loading rate and heating temperature. The test results of natural cooling and water immersion cooling treatment were compared, which showed that the strength of water-cooled specimens is higher than that of naturally cooled specimens before the heating temperature reaches 400 °C and becomes much lower when the heating temperature is higher than 400 °C. Based on the experimental study, a dynamic non-linear elastic constitutive equation was established using a particle swarm optimization algorithm and an inversion analysis method. These results could provide theoretical references for the design of the ultimate strength of concrete materials for practical applications, such as fire and explosion prevention.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High temperature-cooling damage on mechanical properties for concrete is tested. </LI> <LI> The strain rate is directly related to the loading rate and heating temperature. </LI> <LI> 400 °C can be considered as the threshold of high temperature-water cooling damage. </LI> <LI> Dynamic non-linear elastic constitutive equation is established. </LI> </UL> </P>
Bimodal Phenomenon of the Stress–Strain Curve During Hot Compression of LA43M Mg–Li Alloy
Yi Li,Yanjin Guan,Hu Chen,Jiqiang Zhai,Jun Lin,Liang Chen 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10
In this study, the samples of LA43M Mg–Li alloy were compressed to the true strains of 0.12, 0.16, 0.36 and 0.60 under300 °C and the strain rate of 0.1 s−1. Under this condition, the stress–strain curves present a special bimodal phenomenon atthe early deformation stage, which is caused by twinning and dynamic recrystallization. In the process of hot compression,extension twins generated first. Twinning accommodated strain and the glide of twinning dislocations dissipated local strainenergy, resulting in the first local stress drop. Then extension twins coarsened and devoured all the matrix, leading to thechange of grain orientation. Subsequently, dislocations accumulated at the grain boundaries and resulted in the increase instress. With further strain, dynamic recrystallization occurred, discontinuous dynamic recrystallization is the main dynamicrecrystallization mechanism. The generation of dynamic recrystallization resulted in the strain softening and leaded tothe second local stress drop. Twinning retards the occurrence dynamic recrystallization and has a crucial influence on themicrostructure development during the hot compression of LA43M.
Mechanism and Experimental Investigation of Ultra High Pressure Water Jet on Rubber Cutting
Yi Hu,Yong Kang,Xiao-Chuan Wang,Xiao-Hong Li,Xinping LONG,Guang-Yao Zhai,Man Huang 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
The recycle and reuse of rubber materials has become a global environment problem with the fast increasing amount of waste rubber. Compared to traditional recycle methods, ultra high pressure water jet, as a fast developing tool of cool cutting, can be used inrecycling rubber materials without damaging the internal organization structure of materials. This paper investigates ultra highpressure jet cutting rubber in mechanism and experiment. Different from metallic materials and brittle materials, rubber materialsare cut by the force of shear and tensile under the impinging of ultra high pressure water jet and the erosion of high speed waterflow with rubber powder. The overall structure of kerf is Y shape. The upper section of Y shape is caused by shear, the middle sectionis resulted from both shear and tensile, and the bottom section is a result of the erosion and the tensile. The results of experimentshow: (1) a significant linear correlation between cutting depth and pump pressure;(2) 2.0 mm/s is the optimal transverse velocityunder the current experiment condition;(3) the cutting depth has a decreasing tendency with the stand-off distance increased. It canbe concluded from orthogonal analysis that pump pressure has a signification effect on cutting depth, nozzle transverse velocity isnot remarkable, and the effect of stand-off distance is not obvious.
Enhancement of Innate and Adaptive Immune Functions by Multiple Echinacea Species
Zili Zhai,Yi Liu,Lankun Wu,David S. Senchina,Eve S. Wurtele,Patricia A. Murphy,Marian L. Kohut,Joan E. Cunnick 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.3
Echinaceapreparations are commonly used as nonspecific immunomodulatory agents. Alcohol extracts fromthree widely used Echinaceaspecies, Echinacea angustifolia, Echinacea pallida, and Echinacea purpurea, were investigatedfor immunomodulating properties. The three Echinaceaspecies demonstrated a broad difference in concentrations of indi-vidual lipophilic amides and hydrophilic caffeic acid derivatives. Mice were gavaged once a day (for 7 days) with one of theEchinaceaextracts (130 mg/kg) or vehicle and immunized with sheep red blood cells (sRBC) 4 days prior to collection ofimmune cells for multiple immunological assays. The three herb extracts induced similar, but differential, changes in the per-centage of immune cell populations and their biological functions, including increased percentages of CD49. and CD19.lymphocytes in spleen and natural killer cell cytotoxicity. Antibody response to sRBC was significantly increased equally byextracts of all three Echinacea species. Concanavalin A-stimulated splenocytes from E. angustifolia- and E. pallida-treatedmice demonstrated significantly higher T cell proliferation. In addition, the Echinaceatreatment significantly altered the cy-tokine production by mitogen-stimulated splenic cells. The three herbal extracts significantly increased interferon-. produc-tion, but inhibited the release of tumor necrosis factor-. and interleukin (IL)-1.. Only E. angustifolia- and E. pallida-treatedmice demonstrated significantly higher production of IL-4 and increased IL-10 production. Taken together, these findingsdemonstrated that Echinaceais a wide-spectrum immunomodulator that modulates both innate and adaptive immune responses.In particular, E. angustifoliaor E. pallidamay have more anti-inflammatory potential.
Phenolic constituents from Parakmeria yunnanensis and their anti-HIV-1 activity
Shan-Zhai Shang,Huan Chen,Cheng-Qin Liang,Zhong-Hua Gao,Xue Du,Rui-Rui Wang,Yi-Ming Shi,Yong-Tang Zheng,Wei-Lie Xiao,Han Dong Sun 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.10
Three new phenolic compounds, yunnanensinsA–C (1–3), together with fourteen known ones (4–17),were isolated from the leaves and stems of Parakmeriayunnanensis. The structures of new compounds wereestablished on the basis of extensive spectroscopic analyses. Several compounds showed weak anti-HIV-1 activity.
Zhang, Yalong,Yi, Min,Ren, Jing,Zhai, Maolin,Ha, Hongfei The Polymer Society of Korea 2003 Macromolecular Research Vol.11 No.3
The dependence of electrical conductivity on concentrations of diallyldimethylammonium chloride (DADMAC) monomer, linear poly(DADMAC) and their mixture monomer/poly(DADMAC) in dilute aqueous solution exhibits a linear relationship. It was possible to calculate conversion of DADMAC polymerization by measuring its electric conductivity. Although the electrical conductivity of the poly(DADMAC) solution decreased with increasing its molecular weight, in the process of UV or ionizing radiation polymerization the molecular weight of the polymers could be kept constant in the case of fixed temperature, UV-luminous intensity or dose rate. Based on the method mentioned above, the kinetics of UV induced polymerization of DADMAC in aqueous solution was studied; the overall activation energy of polymerization of DADMAC in the water phase was calculated to be 18.8 kJ mol$^{-1}$ . ${\gamma}$-Radiation-induced polymerization of DADMAC in aqueous solution as a function of absorbed dose was studied as well. The conversion of DADMAC increased quickly with dose before 30 kGy and then increased slowly. The experimental data of both UV- and ${\gamma}$-induced polymerization were verified to be reliable by inverted ultracentrifugation method.
Feeding and related morphology of salivary glands of Bradysia odoriphaga (Diptera: Sciaridae)
Huan-Huan Gao,Yi-Fan Zhai,Xue Cao,Xian-Hong Zhou,Zhong-Yan Wang,Fang Wang,Hao Chen,Yi Yu 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.2
The amount of Bradysia odoriphaga larval feeding at each developmental stage and the related morphology of salivary glands were investigated in this study. The amount of daily feeding in the third instar was greatest among all the developmental stageswhile the amount of cumulative feeding in the fourth-instar accounted for 53.56% of the total amount of larval feeding. The daily amount of feeding by B. odoriphaga during the whole larval stage peaked in the 8th and 14th day after hatching. The paired and transparent salivary glands of B. odoriphaga were characterized by two distinct regions: an anterior region and a posterior region. At the fourth-instar and pupal stage, the length of salivary glands decreased significantly compared with that of the third-instar, and the integrity of epithelium cytoplasm in the salivary glands also decreased markedly because of the formation of cytoplasmic vacuoles and degradation of rough endoplasmic reticulum and mitochondria. We concluded that the decrease of daily feeding amount in the last instar was related to the structural change of salivary gland closely. The function of salivary glands in B. odoriphaga was mainly secretion of silk and cocooning-like materials during the last larval instar.