Analysis of Honeycomb and Sandwich Structure Compression Property and the Damage of Double Cell Wall

Lihong Xu,Can Ni,Gang Liu,Junli Li 한국섬유공학회 2023 Fibers and polymers Vol.24 No.9

Sandwich structure is widely used in aviation field due to their high out-of-plane compression properties, shear properties, and outstanding energy absorption characteristics. During the forming process, the aluminum honeycomb will form double cell wall because of adhesive layers. The double cell wall has a great influence on the compressive properties, but there are only few researches on it. In this paper, the influence of double cell wall on the compression performance of sandwich structure was studied, and the failure process of double cell was analyzed from micro perspective. Finite element models of aluminum honeycomb and sandwich structure were established in the software ABAQUS. Moreover, the unit model including double cell wall and single cell wall was also established, and then the effectiveness of the simulation was verified by experiments. The compression experiment was carried out on the universal test machine with sandwich structure and the test speed was set as 2 mm/min. The results show that the failure occurs from one end when the aluminum honeycomb faces with flat compression load alone, while the failure of the sandwich structure starts from the middle of the core. The adhesive layer in the double cell wall is subjected to both compressive stress and tensile stress, and the failure occurs first in tension position. Then, the effects of double cell wall different bonding parameters and different panel layering angles on the compressive properties of the structure were studied. The results show that the structural compression performance increases slowly after the bonding length reaches 4 mm, and the bonding thickness less than 0.1 mm has little influence on the compression performance. The fiber orientation of the panel close to the core can be designed to be 90° which is parallel to the double cell wall, which can effectively improve the flat compression performance.

Clinical Characteristics of Patients with Persistent Apogeotropic and Persistent Geotropic Direction-Changing Positional Nystagmus

Si Lihong,Shen Bo,Li Yuanzhe,Ling Xia,Li Kangzhi,Yang Xu 대한신경과학회 2021 Journal of Clinical Neurology Vol.17 No.3

Background and Purpose This study aimed to determine the clinical features, diagnosis, and treatment of patients with persistent geotropic (pG) and persistent apogeotropic (pAG) direction-changing positional nystagmus (DCPN). Methods This retrospective study included 30 patients with pG-DCPN and 44 patients with pAG-DCPN. All patients underwent neurological and neurotological examinations, including an evaluation of gaze-evoked nystagmus, eye-movement tests, and assessments of limb ataxia and balance, as well as magnetic resonance imaging to exclude central causes. The characteristics of positional nystagmus were detected using the supine roll test (SRT) and bow-andlean test (BLT). The null point (NP) at which the nystagmus disappeared was determined. All patients were treated with the barbecue maneuver, and treatment efficacy was evaluated immediately, 1 week, and 1 month after treatment. Results The history of diseases associated with atherosclerosis, peripheral vestibular disorders, otological disease, and migraine differed significantly between patients with pG-DCPN and pAG-DCPN. The affected sides of persistent horizontal DCPN can be determined using the SRT and the BLT, while determining the second NP and vestibular function as well as performing an audiological evaluation can be used to assist in identifying the affected side. The efficacy rates immediately and 1 week after treatment with the barbecue maneuver were higher in patients with pAG-DCPN than in patients with pG-DCPN. Conclusions pAG-DCPN was more compatible with the characteristics of cupulolithiasis, and pG-DCPN was more likely to be associated with a light cupula rather than canalolithiasis. pAG-DCPN was more likely to be accompanied by a disease associated with atherosclerosis, while pG-DCPN was often accompanied by autoimmune-related diseases and a history of migraine. The associations between pAG-DCPN, pG-DCPN, and the above-mentioned diseases need to be clarified further. The canalith-repositioning maneuver was effective in patients with pAG-DCPN and ineffective in patients with pG-DCPN, but most cases of pGDCPN are self-limiting.

Salvianolic acid B ameliorates psoriatic changes in imiquimodinduced psoriasis on BALB/c mice by inhibiting inflammatory and keratin markers via altering phosphatidylinositol-3-kinase/ protein kinase B signaling pathway

Shoufan Wang,Lihong Zhu,Yihou Xu,Zongbi Qin,Aiqin Xu 대한생리학회-대한약리학회 2020 The Korean Journal of Physiology & Pharmacology Vol.24 No.3

acid B (SAB) is an active phytocomponent of a popular Chinese herb called Radix Salvia militiorrhiza with numerous biological properties. The anti-psoriasis activity of SAB was examined by evaluating various psoriasis inflammatory and keratin markers against imiquimod (IMQ)-induced psoriasis on BALB/c mice. Totally 50 healthy BALB/c mice were evenly divided into 5 groups including control, drug control (SAB; 40 mg/kg), IMQ-induced psoriasis (5%), IMQ exposure and treated with SAB (40 mg/kg), or standard methotrexate (MTX; 1 mg/kg). Mice supplemented with either SAB or MTX significantly lowered the values of psoriasis area severity index (PASI), erythema, scaling, skin thickness, inflammatory markers (interleukin [IL]- 22/23/17A/1β/6) and lipid peroxidation product (malondialdehyde). Also, IMQ exposed BALB/c mice treated with SAB or MTX display lesser histopathological changes with enhanced antioxidant activities (catalase, superoxide dismutase). Moreover, the protein expression of keratin markers (K16 and K17) and phosphatidylinositol- 3-kinase (PI3K)/protein kinase B (Akt) signaling proteins (pAkt/Akt and pPI3K/PI3K) were significantly downregulated after administration with SAB and MTX as compared with IMQ induced mice. Taking together, SAB and MTX significantly ameliorate psoriatic changes by inhibiting psoriatic inflammatory and keratin markers through abolishing PI3K/Akt signaling pathway. However, further studies (clinical trials) are needed to confirm the anti-psoriatic property of SAB before recommending to psoriasis patients.

Setpoint Decision Support Strategy and Adaptive Hybrid Control of Greenhouse Climate: A Simulation Study

Yuanping Su,Lihong Xu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.11

The energy saving performance of the greenhouse production is significantly impacted by the setpoint of the greenhouse climate and the control method. How to select a good setpoint for the greenhouse climate is an important issue. To solve this issue, this work proposes a decision support strategy to generate online the setpoint for the control of the greenhouse climate. In this approach, it uses online receding horizon multi-objective optimization to maximize the crop yield and minimize the energy consumption. Thus, it can obtain the optimal daily mean temperature of each day. Since such method does not directly optimize the sepoint of the greenhouse climate, it must introduce the daily mean temperature serialization method to transform the daily mean temperature into the setpoint curve. Once the sepoint is generated, the next task is to solve the control problem of the greenhouse climate. Since the greenhouse climate is a complex nonlinear system, and is impacted by the greenhouse structure and material, the weather and the crop growth. Therefore, it is usually difficult to accurately model the greenhouse climate. The great uncertainty of the system makes the control problem of the greenhouse climate be difficult to solve. To solve this problem, this work proposes an adaptive hybrid control based on a greenhouse climate model with unknown timevariant parameters. In this control method, neural network is used to estimate the model parameters. Based on such a model, an adaptive control law is derived to generate the control inputs of the heating, fogging and CO2 injecting, while the control strategies of the ventilation, shading and thermal screen are determined by the expert rules. The simulation results indicate that such adaptive hybrid control method can achieve good control performance and economic efficiency.

Diversity and Functions of Endophytic Fungi Associated with Roots and Leaves of Stipa purpurea in an Alpine Steppe at Qinghai-Tibet Plateau

( Xiaoyan Yang ),( Hui Jin ),( Lihong Xu ),( Haiyan Cui ),( Aiyi Xin ),( Haoyue Liu ),( Bo Qin ) 한국미생물 · 생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.7

Stipa purpurea is a unique and dominant herbaceous plant species in the alpine steppe and meadows on the Qinghai-Tibet Plateau (QTP). In this work, we analyzed the composition and diversity of the culturable endophytic fungi in S. purpurea according to morphological and molecular identification. Then, we investigated the bioactivities of these fungi against plant pathogenic fungi and 1- aminocyclopropane-1-carboxylate deaminase (ACCD) deaminase activities. A total of 323 fungal isolates were first isolated from S. purpurea, and 33 fungal taxa were identified by internal transcribed spacer primers and grouped into Ascomycota. The diversity of endophytic fungi in S. purpurea was significantly higher in roots as compared to leaves. In addition, more than 40% of the endophytic fungi carried the gene encoding for the ACCD gene. The antibiosis assay demonstrated that 29, 35, 28, 37 and 34 isolates (43.9, 53.1, 42.4, 56.1, and 51.5%) were antagonistic to five plant pathogenic fungi, respectively. Our study provided the first assessment of the diversity of culturedepending endophytic fungi of S. purpurea, demonstrated the potential application of ACCD activity and antifungal activities with potential benefits to the host plant, and contributed to high biomass production and adaptation of S. purpurea to an adverse environment.

Cyclooxygenase‐2 prevents fas‐induced liver injury through up‐regulation of epidermal growth factor receptor

Li, Guiying,Han, Chang,Xu, Lihong,Lim, Kyu,Isse, Kumiko,Wu, Tong Wiley Subscription Services, Inc., A Wiley Company 2009 Hepatology Vol.50 No.3

<P><B>Abstract</B></P><P>Cyclooxygenase‐2 (COX‐2)–derived prostaglandins participate in a number of pathophysiological responses such as inflammation, carcinogenesis, and modulation of cell growth and survival. This study used complementary approaches of COX‐2 transgenic (Tg) and knockout (KO) mouse models to evaluate the mechanism of COX‐2 in Fas‐induced hepatocyte apoptosis and liver failure <I>in vivo</I>. We generated Tg mice with targeted expression of COX‐2 in the liver by using the albumin promoter‐enhancer–driven vector. The COX‐2 Tg, COX‐2 KO, and wild‐type mice were treated with the anti‐Fas antibody Jo2 (0.5 μg/g of body weight) for 4 to 6 hours, and the extent of liver injury was assessed by histopathology, serum aminotransferases, TUNEL staining, and caspase activation. The COX‐2 Tg mice showed resistance to Fas‐induced liver injury in comparison with the wild‐type mice; this was reflected by the lower alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, less liver damage, and less hepatocyte apoptosis (<I>P</I> < 0.01). In contrast, the COX‐2 KO mice showed significantly higher serum ALT and AST levels, more prominent hepatocyte apoptosis, and higher levels of caspase‐8, caspase‐9, and caspase‐3 activity than the wild‐type mice (<I>P</I> < 0.01). The COX‐2 Tg livers expressed higher levels of epidermal growth factor receptor (EGFR) than the wild‐type controls; the COX‐2 KO livers expressed the lowest levels of EGFR. Pretreatment with a COX‐2 inhibitor (NS‐398) or an EGFR inhibitor (AG1478) exacerbated Jo2‐mediated liver injury and hepatocyte apoptosis. <I>Conclusion:</I> These findings demonstrate that COX‐2 prevents Fas‐induced hepatocyte apoptosis and liver failure at least in part through up‐regulation of EGFR. (H<SMALL>EPATOLOGY</SMALL> 2009.)</P>

Effects of short-term soil tillage management on activity and community structure of denitrifiers under double-cropping rice field

Haiming Tang,Chao Li,Kaikai Cheng,Lihong Shi,Li Wen,Xiaoping Xiao,Yilan Xu,Weiyan Li,Ke Wang 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.11

Soil physical and chemical characteristics, soil potential denitrification rates (PDR), community composition and nirK-, nirS- and nosZ-encoding denitrifiers were studied by using MiSeq sequencing, quantitative polymerase chain reaction (qPCR), and terminal restriction fragment polymorphism (T-RFLP) technologies base on short-term (5-year) tillage field experiment. The experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), and rotary tillage with crop residue removed as control (RTO). The results indicated that soil organic carbon, total nitrogen and NH4 +-N contents were increased with CT, RT and NT treatments. Compared with RTO treatment, the copies number of nirK, nirS and nosZ in paddy soil with CT, RT and NT treatments were significantly increased. The principal coordinate analysis indicated that tillage management and crop residue returning management were the most and the second important factors for the change of denitrifying bacteria community, respectively. Meanwhile, this study indicated that activity and community composition of denitrifiers with CT, RT and NT treatments were increased, compared with RTO treatment. This result showed that nirK, nirS and nosZ-type denitrifiers communities in crop residue applied soil had higher species diversity compared with crop residue removed soil, and denitrifying bacteria community composition were dominated by Gammaproteobacteria, Deltaproteobacteria, and Betaproteobacteria. Therefore, it is a beneficial practice to increase soil PDR level, abundance and community composition of nitrogen-functional soil microorganism by combined application of tillage with crop residue management.

Greenhouse Climate Fuzzy Adaptive Control Considering Energy Saving

Yuanping Su,Erik D. Goodman,Lihong Xu 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.4

This paper proposes a fuzzy adaptive control approach to solve greenhouse climate control problem. Theaim is to ensure the controlled environmental variables to track their desired trajectories so as to create a favorableenvironment for crop growth. In this method, a feedback linearization technique is first introduced to derive thecontrol laws of heating, fogging and CO2 injection, then to compensate for the saturation of the actuators, a fuzzylogic system (FLS) is used to approximate the differences between controller outputs and actuator outputs due toactuator constraints. A robust control term is introduced to eliminate the impact of external disturbances and modeluncertainty, and finally, Lyapunov stability analysis is performed to guarantee the convergence of the closed-loopsystem. Taking into account the fact that the crop is usually insensitive to the change of the environment insidethe greenhouse during a short time interval, a certain amount of tracking error of the environmental variables isusually acceptable, which means that the environmental variables need only be driven into the corresponding targetintervals. In this case, an energy-saving management mechanism is designed to reduce the energy consumption asmuch as possible. The simulation results illustrate the effectiveness of the proposed control scheme.

Optical temperature sensing properties of Yb3+/Tm3+ co-doped NaLuF4 crystals

Lili Tong,Xiangping Li,Ruinian Hua,Lihong Cheng,Jiashi Sun,Jinsu Zhang,Sai Xu,Hui Zheng,Yanqiu Zhang,Baojiu Chen 한국물리학회 2017 Current Applied Physics Vol.17 No.7

Yb3þ/Tm3þ and Yb3þ/Er3þ co-doped NaLuF4 crystals were synthesized by a facile hydrothermal method. The optical temperature sensing properties of Tm3þ based upon its two thermally coupled energy levels 3F2, 3 and 3H4 were systematically investigated by means of fluorescence intensity ratio (FIR) technique. The 980 nm laser-induced thermal effect on Tm3þ doped NaLuF4 crystals was studied by using Er3þ doped sample as thermal probe. The temperature sensitivity of Tm3þ in NaLuF4: Yb3þ/Tm3þ crystals shows a nonlinear dependence on temperature, and the maximum value is about 0.00045 K『1 at 600 K. The accuracy and reliability of the optical thermometry based on Tm3þ in NaLuF4: Yb3þ/Tm3þ crystals has been checked by using Yb3þ/Er3þ co-doped sample as temperature sensing unit. The results demonstrate that NaLuF4: Yb3þ/Tm3þ crystals have good sensing stability and may have potential application for the optical thermometry.

Nematicidal activity against Aphelenchoides besseyi and Ditylenchus destructor of three biflavonoids, isolated from roots of Stellera chamaejasme

Hui Jin,Haiyan Cui,Xiaoyan Yang,Lihong Xu,Xudong Li,Rentao Liu,Zhiqiang Yan,Xiuzhuang Li,Weili Zheng,Yuhui Zhao,Xiaoxia Song,Lihua Zhong,Anxiang Su,Bo Qin 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.4

Aphelenchoides besseyi and Ditylenchus destructor can cause serious problems for a number of important agricultural crops and vegetables. In this study, the ethanol extract of Stellera chamaejasme L. roots showed strong nematicidal activity against Aphelenchoides besseyi and Ditylenchus destructor. By using a bioactivity-driven fractionation, three biflavonoids were isolated from the extract and their structures were identified by mass and nuclear magnetic resonance spectral data. Nematicidal activity bioassays revealed that isoneochamaejasmin A had the strongest nematicidal activity against A. besseyi and D. destructor with LC 50 values of 2.32 and 0.18 mM at 72 h, respectively. Chamaejasmenin B displayed weaker nematicidal activity against A. besseyi with an LC 50 value of 3.94 mM at 72 h. Neochamaejasmin B induced the lowest mortality against D. destructor with an LC 50 values of 15.6 mM at 72 h. These results suggested that the kind and position of substitutions and the relative configuration of 2-H/3-H and 2”-H/3”-H could be considered as important factors responsible for the nematicidal activity of these purified C-3/C-3″ biflavonoids.