Age-stage, two-sex life tables of the maple poison moth (Lymantria nebulosa Wileman) at different ambient temperatures

Lei Ling,Huang Hui Jing,Yi Jin Yu,Qiu Lin,Ding Wen Bin,He Hua Liang,Yi Tu Yong,Li You Zhi,Xue Jin 한국곤충학회 2021 Entomological Research Vol.51 No.4

The maple poison moth (MPM), Lymantria nebulosa (Wileman), is a Lepidopteran defoliator and one of the most important pests of Liquidambar formosana Hance. The objective of this study was to determine the effects of temperature on the population growth and reproduction of this species. MPM were raised in artificial climate chambers in a laboratory at 21 ± 1°C, 24 ± 1°C, 27 ± 1°C, 30 ± 1°C, 33 ± 1°C and 36 ± 1°C, under a relative humidity (RH) of 70% ± 10% and a 14 L:10D photoperiod, and age-stage, two-sex life tables complied for insects at each temperature. The developmental duration, adult preoviposition period and overall preoviposition period decreased with temperature in a time-dependent manner. The growth curves of the different temperature groups overlapped considerably. The highest larval survival rate (80%) was recorded at 30 ± 1°C. At 36°C only a few eggs hatched and the first instar could not complete the first molt. We consequently regard 36°C as the lethal temperature threshold for this species. Life expectancy decreased with age under all six temperatures. The endogenous growth rate was significantly lower at 21 ± 1°C than at the other temperatures, and was highest in 30 ± 1°C group. The net growth rate of the 30 ± 1°C group was also significantly higher than others. Reproductive parameters were highest at 27 ± 1°C and 30 ± 1°C. Although environmental factors absent from the laboratory environment may limit the generality of our results, they nonetheless provide a theoretical basis for developing integrated control methods for MPM in the wild.

Self-Healing and Shape Memory Linear Polyurethane Based on Disulfide Linkages with Excellent Mechanical Property

Lei Ling,Jinhui Li,Guoping Zhang,Rong Sun,Ching-Ping Wong 한국고분자학회 2018 Macromolecular Research Vol.26 No.4

Self-healing polymeric materials have attracted extensively interests due to the ability to heal the damage autonomously. The self-healing systems based on dynamic disulfide bonds have been the most promising due to the efficient healing capacity at a mild condition. However, it is still of great challenge for designing the polymer with excellent mechanical and self-healing property by a simple synthetic route. Herein, a novel series of self-healing linear polyurethanes with the disulfide linkage as the grafting point were developed. The synthetic polymers all exhibited excellent mechanical properties (breaking strength and elongation at break were as much as 31.91 MPa and 1156% for PU-A). Meanwhile, the effects of different ratios of soft/hard segments on the mechanical properties and healing efficiencies have been investigated by stress-strain tests. The results showed that with the increase of soft segments contents, the breaking strength and elongation at break of the polymer improved significantly, while the healing efficiency and Young’s modulus showed a declining trend. The self-healing polyurethane can quickly restore its over 90% of mechanical property after healing at moderate temperature for 10 min. The cyclic tensile tests also showed the dissipated efficiencies and self-recovery abilities of the polymers. Finally, the recovery capability tests verified the shape memory effect in the polymers, which can replace an external force to accelerate the healing process.

Experimental Study on Interfacial Shear Performance of RC Beams Added to Existing RC Columns

Xin-Ling Wang,Lei-Lei Jin,Ke Li,Jun-Tao Zhu 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.11

The primary objectives of this study were to experimentally investigate the shear characteristicsof the interface between an existing RC column and a reinforced concrete (RC) beam added to the existing RC column, and to propose a formula for estimating the shear capacity of the beam-column interface. The major test variables consisted of concrete strength, added steel reinforcement ratio and shear span to depth ratio. Failure characteristics, displacements at the loading point, slips of the beam-column interface, and shear capacities of the beam-column interface were analyzed. Test results indicate that both the shear capacity of the beam-column interface and the corresponding interfacial slip increased with a decrease in shear span to depth ratio. In addition, as concrete strength grew, the shear capacity of the beam-column interface increased, but the interfacial slip corresponding to the interfacial shear capacity remained almost unchanged. Moreover, both the shear capacity of the beam-column interface and the corresponding interfacial slip increased with an increase in the longitudinal steel reinforcement ratio of the added RC beam. A formula for predicting the shear capacity of the beam-column interface was developed. The test results validate the proposed formula and provide important guidance for the design of the RC beam added to the existing RC column.

Improvement of Lipid and Terpenoid Yield in Thraustochytrids Using Chemical Regulators: A Review

Zi-Lei Chen,Lin-Hui Yang,Ling-Ling Tong,Yue Wang,Meng-Zhen Liu,Dong-Sheng Guo 한국생물공학회 2023 Biotechnology and Bioprocess Engineering Vol.28 No.5

For the increasing demand for lipids and terpenoids in humans, biological fermentation has become an attractive choice due to the safety and sustainability. Thraustochytrids have been identified as promising producers of polyunsaturated fatty acids because of their high lipid content and simple fatty acid composition. In addition, thraustochytrids are also potential producers of terpenoids for their completed mevalonate pathway. Chemical regulators can be used to stimulate or inhibit metabolic pathways, which are equivalent to effects of overexpression and suppression approaches. The application of chemical regulators is potentially an easy and practical approach to improve the lipid and terpenoid yield in thraustochytrids, which has become a research focus. In this review, the mechanisms of chemical regulators promoting lipid and terpenoid biosynthesis in thraustochytrids are elucidated. Various chemical regulators which can directly enhance the biosynthesis of lipids and terpenoids are summarized depending on the type of chemicals. In addition, some chemical regulators are demonstrated to indirectly improve lipid and terpenoid yield by reducing the conversion of metabolites and reducing oxidative stress. Therefore, the addition of chemical regulators can be a useful alternative strategy for improving lipid and terpenoid accumulation in large-scale cultivation of thraustochytrids.

Research on the Discrimination of Hatching Eggs Activity Based on Thermal Imaging : A Food Nondestructive Testing Practice

Liu Hai-ling,Cai Jian-rong,Sun Li,Yuan Lei-ming,Liu Meng-lei 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.2

The hatching eggs in 4-16 days incubation were from incubator of 38.5℃ to 22℃ for natural cooling and the time series images were acquired by thermal imaging technology. Analyzing the cooling curve and the cooling area and region growing, ellipse fitting, morphological processing and other methods were used to extract eggs region of interest; time series images superposition and contrast enhancement were used to raise the temperature close to the different categories of eggs gray differences; the ratio of gray value≦150 and entire ROI area was seen as characteristic parameters and the decision threshold was set according to minimum error rate Bayes rule. The non-fertilized eggs in incubating 4 days was 89.6% overall recognition and the dead embryo eggs in incubating 16 days was 96.3% overall recognition. Research showed that thermal imaging technology combined image processing technology can achieve non-destructive testing of hatching eggs activity.

Microbial Conversion of Rare Ginsenoside Rf to 20(S)-protopanaxatriol by Aspergillus Niger

Lei Liu,Chun Ling Wang,Hoang Gia Trinh,Mi Ra Lee,Beom Sik Yun,Chun Yan Wang,Zhen Wang,Dong Liang Zhang,Zheng Li,Jing Jie Li,Chang Keun Sung 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2009 한국식품저장유통학회 학술대회 Vol.2009 No.-

GLOBAL EXISTENCE AND ASYMPTOTIC BEHAVIOR OF PERIODIC SOLUTIONS TO A FRACTIONAL CHEMOTAXIS SYSTEM ON THE WEAKLY COMPETITIVE CASE

Lei, Yuzhu,Liu, Zuhan,Zhou, Ling Korean Mathematical Society 2020 대한수학회보 Vol.57 No.5

In this paper, we consider a two-species parabolic-parabolic-elliptic chemotaxis system with weak competition and a fractional diffusion of order s ∈ (0, 2). It is proved that for s > 2p₀, where p₀ is a nonnegative constant depending on the system's parameters, there admits a global classical solution. Apart from this, under the circumstance of small chemotactic strengths, we arrive at the global asymptotic stability of the coexistence steady state.

NOLD: A Neural-Network Optimized Low-Resolution Decoder for LDPC Codes

Lei Chu,Huanyu He,Ling Pei,Robert C. Qiu 한국통신학회 2021 Journal of communications and networks Vol.23 No.3

The min-sum (MS) algorithm can decode Low-densityparity-check (LDPC) codes with low computational complexity atthe cost of slight performance loss. It is an effective way to realizehardware implementation of the min-sum decoder by quantizingthe floating belief messages (i.e., check-to-variable messages andvariable-to-check messages) into low-resolution (i.e., 2–4 bits) ver sions. However, such a way can lead to severe performance degra dation due to the finite precision effect. In this paper, we proposea neural-network optimized low-resolution decoding (NOLD) al gorithm for LDPC codes to deal with the problem. Specifically,the optimization of decoding parameters (i.e., scaling factors andquantization step) is achieved in a hybrid way, in which we con catenate a NOLD decoder with a customized neural network. Alllearnable parameters associated with the decoding parameters areassigned to each neuron in the proposed method. What’s more, wedesign a new activation function whose outputs are close to the em ployed quantizer ones when network parameters are finally opti mized off-line. Finally, the performance of the proposed method isverified by numerous experiments. For the case of 2-bit decoding,the proposed approach significantly outperforms several conven tional decoders at the expense of slightly increased off-line trainingtime. Besides, the proposed method with 4-bit quantization incursonly 0.1 dB performance loss compared with the floating min-sumdecoder at the coded bit-error-rate of 10−5. Moreover, we showthat the proposed NOLD decoder works over a wide range of chan nel conditions for regular and irregular LDPC codes. Simulationcode for reproductive results is publicly available1.

Three New Iridoid Glucosides from the Roots of Patrinia scabra

Lei Di,You-Xing Zhao,Kai-Jin Wang,Ling-Bo Zu,Ning Li,Zhi Wang 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.9

To probe the chemical constituents of Patrinia scabra, we undertook the phytochemical investigation on its roots, which led to the isolation and elucidation of three new iridoid glucosides, scabroside A-C (1-3), along with three known iridoids, jatamanin J (4), isopatriscabroside I (5) and loganic acid (6) from the aqueous fraction of the ethanolic extract of the roots. The structures and relative configurations of the three new compounds were elucidated by spectroscopic methods including IR, UV, MS, 1D and 2D NMR experiments. Compound 3 was an unusual iridoid with an oxygen bridge connecting C-3 and C-8.

Bending ratcheting behavior of pressurized straight Z2CND18.12N stainless steel pipe

Lei Wang,Gang Chen,Jianbei Zhu,Xiuhu Sun,Yunhui Mei,Xiang Ling,Xu Chen 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.6

The ratcheting effect greatly challenges the design of piping components. With the assistance of the quasi-three point bending apparatus, ratcheting and the ratcheting boundary of pressurized straight Z2CND18.12N stainless steel pipe under bending loading and vertical displacement control were studiedexperimentally. The characteristics of progressive inelastic deformation in axial and hoop directions of the Z2CND18.12N stainless steel pipes were investigated. The experiment results show that the ratcheting strainoccurs mainly in the hoop direction while there is less ratcheting strain in the axial direction. Thecharacteristics of the bending ratcheting behavior of the pressure pipes were derived and compared under load control and displacement control, respectively. The results show that the cyclic bending loading and the internal pressure affect the ratcheting behavior of the pressurized straight pipe significantly under loadcontrol. In the meantime, the ratcheting characteristics are also highly associated with the cyclicdisplacement and the internal pressure under displacement control. All these factors affect not only the saturation of the ratcheting strain but the ratcheting strain rate. A series of multi-step bending ratcheting experiments were conducted under both control modes. It was found that the hardening effect of Z2CND18.12N stainless steel pipe under previous cyclic loadings no matter with high or low displacement amplitudes is significant, and the prior loading histories greatly retard the ratcheting strain and its rate under subsequent loadings. Finally, the ratcheting boundaries of the pressurized straight Z2CND18.12N stainless steel pipe were determined and compared based on KTA/ASME, RCC-MR and the experimental results.