A Novel Maximum Power Point Tracking Algorithms for Stand-alone Photovoltaic System

Shiqiong Zhou,Longyun Kang,Jing Sun,Guifang Guo,Bo Cheng,Binggang Cao,Yiping Tang 제어·로봇·시스템학회 2010 International Journal of Control, Automation, and Vol.8 No.6

A novel control algorithm, namely subsection adaptive hill climbing method (SSAHC), for seeking the maximum power point (MPP) of a photovoltaic (PV) panel for any temperature and solar radiation level is proposed. The algorithm is thus a combination of the subsection and adaptive hill climbing me-thods. In this algorithm, the characteristic curve of power-voltage of PV panel was divided into three subsections, namely large step approximation section, adaptive hill climbing section and maximum power section. Using this method, the MPP tracker (MPPT) can tune adaptively the step to track the MPP of PV system. The main advantage of the MPPT controlled by this new algorithm, when is compared with others, is that it can draw more power at a certain weather condition , especially, in case solar radiation changes rapidly at higher radiation.

Modelling and Prediction of Stress Relaxation for Thermal Bonded Nonwoven Geotextiles

Shiyuan Sun,Xiaoping Gao,Chunhong Fu,Yudong Zhou,Xiaoying Wei,Jiaxin Li,Yiping Qiu 한국섬유공학회 2020 Fibers and polymers Vol.21 No.7

Stress relaxation experiments were performed on three types of thermal bonded nonwoven geotextiles in this studyto model and predict their stress relaxation behaviors. Four mechanical models, including the standard linear solid mechanicsmodel, Eyring’s model, the modified two-Maxwell-unit model and the modified three-Maxwell-unit model were used topredict stress values for 600 h based on 3 and 90 h experimental relaxation data. Results indicated that Eyring’s model and themodified three-Maxwell-unit model fitted the experimental results better than the other two. Estimation using modified three-Maxwell-unit model seemed to construct an upper bound while that using Eyring’s model form a lower bound for thecorresponding experimental data. In addition, predicted curves were much closer to the experimental curve when equationsof the two models were built with the 90 h experimental data than those data of 3 h. Thus, the prediction capability of the twomodels can be substantially improved by employing the data with longer time. In summary, the combination of the modifiedthree-Maxwell-unit model and Eyring’s model can well forcast the range of actual stress during stress relaxation experimentswith the longer term experimental data.

Effects of intermittent chemical dosing on volatile sulfur compounds in sewer headspace

Guijiao Zhang,Tianfeng Gu,Yongchao Zhou,David Z. Zhu,Yiping Zhang 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.3

Volatile sulfur compounds (VSCs), including hydrogen sulfide (H₂S) and volatile organic sulfide compounds (VOSCs), can be produced in sewer systems causing sewer odor problems. In this study, the effects of intermittently dosing ferric iron, hydrogen peroxide, and nitrate on H₂S and VOSCs in sewer headspace were investigated. In order to characterize the composition of VSCs, an HC-3 trace sulfur analyzer and gas chromatograph (GC) equipped with a triple quadrupole-type mass spectrometry (MS) apparatus were used to determine the VSCs. The results indicated that the effect of intermittent addition of 40 mg/L ferric iron or 40 mg/L hydrogen peroxide is limited for VSCs inhibition. The H₂S and VOSCs concentrations increased significantly in the late-stage experiments, even around 20% and 30% respectively higher than the initial average concentrations. However, the intermittent addition of 40 mg N/L nitrate has a relatively stable control effect of H₂S and VOSCs which maintaining 60% removal rate. Moreover, methyl mercaptan (MeSH) was the most abundant compound of the total VOSCs released and the results of the theoretical odor concentration study also indicate MeSH is the main VOSC causing the significant odor problem. Therefore, more attention should be focused on the VOSCs which have extremely low odor threshold.

Effect of Leukocyte-Platelet Rich Fibrin (L-PRF) on Tissue Regeneration and Proliferation of Human Gingival Fibroblast Cells Cultured Using a Modified Method

Mudalal Mahmoud,Wang Zhanqi,Mustafa Shockry,Liu Yiping,Wang Yao,Yu Jize,Wang Shengnan,Sun Xiaolin,Zhou Yanmin 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.5

Background: An in vitro study on rapid culturing method of human gingival fibroblast cells (HGFCs) was established to investigate the potential use of the leukocyte-platelet rich fibrin (L-PRF) in tissue engineering technology, different medical fields, including periodontology and implantology. Methods: Eight biopsies were obtained from eight different donors and a modified culturing technique was developed to obtain HGFCs. The modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay was used to compare the cell viability when the modified culturing method was used in comparison to the standard method. Blood samples were collected from the same patients and L-PRF was isolated using a standard protocol. The releases of platelet-derived growth factor-AA and transforming growth factor-beta1 at various time intervals were observed using enzyme-linked immunosorbent assay (ELISA) kit. The proliferative effect of L-PRF on HGFCs was assessed by the cell counting kit—8 assay. Results: A simple and rapid modified method for in vitro HGFC culture yielded a cellular monolayer within three to nine days after cell culture. L-PRF with three-dimensional polymer fibers released growth factors that peaked during the first three hours and continued to produce up to 10 days. The L-PRF presented a dose-dependent effect on HGFCs proliferation where HGFCs proliferation increased with an increase in L-PRF concentration. Conclusion: The modified technique for the culture of HGFCs might be useful for the development of future experimental and clinical studies, besides L-PRF has great therapeutic potential in oral surgery fields. Background: An in vitro study on rapid culturing method of human gingival fibroblast cells (HGFCs) was established to investigate the potential use of the leukocyte-platelet rich fibrin (L-PRF) in tissue engineering technology, different medical fields, including periodontology and implantology. Methods: Eight biopsies were obtained from eight different donors and a modified culturing technique was developed to obtain HGFCs. The modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay was used to compare the cell viability when the modified culturing method was used in comparison to the standard method. Blood samples were collected from the same patients and L-PRF was isolated using a standard protocol. The releases of platelet-derived growth factor-AA and transforming growth factor-beta1 at various time intervals were observed using enzyme-linked immunosorbent assay (ELISA) kit. The proliferative effect of L-PRF on HGFCs was assessed by the cell counting kit—8 assay. Results: A simple and rapid modified method for in vitro HGFC culture yielded a cellular monolayer within three to nine days after cell culture. L-PRF with three-dimensional polymer fibers released growth factors that peaked during the first three hours and continued to produce up to 10 days. The L-PRF presented a dose-dependent effect on HGFCs proliferation where HGFCs proliferation increased with an increase in L-PRF concentration. Conclusion: The modified technique for the culture of HGFCs might be useful for the development of future experimental and clinical studies, besides L-PRF has great therapeutic potential in oral surgery fields.

Next‑Generation Sequencing‑Based Preimplantation Genetic Testing for De Novo NF1 Mutations

DongJia Chen,Xiaoting Shen,Yan Xu,Bing Cai,Chenhui Ding,Yiping Zhong,Yanwen Xu,Canquan Zhou 한국바이오칩학회 2021 BioChip Journal Vol.15 No.1

Neurofibroma type 1 (NFI) is an autosomal dominant genetic disease associated with cancer and cognitive dysfunction. The 50% de novo mutation rate and numerous mutation types of the NF1 gene pose challenges to preimplantation genetic testing (PGT) for NFI. In 2020, a couple was subjected to next-generation sequencing (NGS)-based PGT at our center. Both husband and wife carried de novo NF1 mutations. Biopsied trophectoderm samples underwent whole-genome amplification using multiple displacement amplification. NGS was conducted to detect NF1 mutations as well as 105 closely linked single-nucleotide polymorphisms (SNPs) flanking NF1. Since no affected family member was available, the affected embryos identified by NF1-targeted sequencing were assigned as probands, based on which a haplotype analysis was constructed with informative SNP sites. Sanger sequencing was administrated for verification. Aneuploidy screening through NGS was performed in the same PGT cycle. Finally, among the nine biopsied blastocysts, two unaffected and euploid blastocysts were obtained in the couple, and one of the blastocysts was transferred in a frozen–thawed embryo transfer (FET) cycle. The outcome of FET is under observation. This study is the first to apply NGS-based PGT for NFI. In cases of sporadic NFI cases without affected family members, NGS-SNP can perform haploid analysis in an accurate manner by assigning the affected embryos as probands.

Simulation Research of Multi-morphological Microstructures Chaining Mechanism of Nano-magnetic Fluid

Lei Yang,Yibiao Chen,Yao Yao,Shuaikang Wei,Yuhui Xie,Decai Li,Jun Yu,Hongming Zhou,Yiping Feng 한국자기학회 2024 Journal of Magnetics Vol.29 No.1

For nano-magnetic fluid(NMF), the magnetic nano-particle(MNP) kinematic behavior in a magnetic field and the chain-like microstructure evolution are important to study the NMF properties at the microscopic level. However, the chain structure formation mechanism and the effects of multiple environmental factors on microstructural morphology remain unclear. In this paper, the interaction of a two-particle system, chain structure formation process, microstructure evolution and response time simulation of NMF is investigated by the discrete element simulation method. The results show that the magnetic dipole and repulsive forces dominate the chain structure formation and evolution under a uniform magnetic field. MNPs assemble into chain-like structures and various complex structures along the magnetic f ield direction. The volume fraction, magnetization intensity and particle size significantly affect the microstructure and the response time. The above study can obtain the specific morphology of the microstructure at different working conditions and broaden the application of NMF in practical engineering.

Polyphyllin I combined with doxorubicin shows chemosensitization effect in vivo and reduces immunotoxicity of doxorubicin

Zhu Xiang,Na Xin,Zeng Yueqin,Xu Yangantai,Chai Dongya,Yang Huanzhi,Miao Jingqian,Zhang Yuan,Yang Fenghua,Wang Yuehu,Zhou Yiping 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.3

Background Polyphyllin I (PPI), a steroidal saponin, exhibits antitumor activity and chemosensitization effect for a broad spectrum of cancer cells, however, its toxicity and chemosensitization effect in vivo is still unknown. Objective We investigated PPI’s cytotoxic activity, toxicity and chemosensitization effect and in vitro and in vivo . Results The IC 50 values of PPI on MCF-7, H22, and S180 tumor cells were 4.37 μmol/L, 1.71 μmol/L, and 0.92 μmol/L, respectively. The LD 50 of PPI was found to be 47.9 mg/kg using ip. injection. PPI at concentrations of 0.3 mg/kg, 0.6 mg/ kg, 1.2 mg/kg, and 2.4 mg/kg (1/80 LD 50 –1/20 LD 50 ) were synergized with DOX of 0.5 mg/kg to inhibit the H22 and S180 tumor growth in vivo by inducing apoptosis without obvious immunotoxicity. PPI exhibited a remarkable hemolytic effect on rabbit erythrocytes (EC 50 = 4.3 μM), while it had no impact in mice. Conclusion Our study revealed that the PPI-sensitized chemotherapeutic effect, when used in safe doses, circumvents immunotoxic side effects of DOX in vivo; thus, helping future clinical research.