Search Coil Magnetometer Based on Multi-parameter Joint Optimization Design in Ultra Low-Frequency Communication

Chunteng Li,Yuzhong Jiang,Guanghui Yang,Fangjun Liu 한국자기학회 2018 Journal of Magnetics Vol.23 No.2

In order to design a kind of high-sensitive, narrow-band and portable search coil magnetometer, based on the principle of magnetic measuring, an equivalent model of search coil magnetometer with parallel matched capacitor is established. The formula of the induced coil is derived, low-noise integrated operational amplifier is designed and made as the preamplifier circuit of search coil magnetometer. The parameters of the inductive coil based on multi-parameter joint optimization are obtained under consideration of the sensitivity, bandwidth, weight and volume of the inductive coil simultaneously. The search coil magnetometer test is completed in the electromagnetic shielding room. And the result shows that the sensitivity of the designed search coil magnetometer is 40 fT√Hz @80 Hz, under the precondition of guaranteeing the weight, volume and bandwidth, which is basically the same as that of the simulation.

Mathematical Analysis Power Spectrum of M-ary MSK and Detection with Optimum Maximum Likelihood

( Zheng Niu ),( Yuzhong Jiang ),( Shuyan G Jia ),( Zhi Huang ),( Wenliang Zou ),( Gang Liu ),( Yu Li ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.8

In this paper, the power spectral density(PSD) for Multilevel Minimum Shift Keyed signal with modulation index h=1/2 (M-ary MSK) are derived using the mathematical method of the Markov Chain model. At first, according to an essential requirement of the phase continuity characteristics of MSK signals, a complete model of the whole process of signal generation is built. Then, the derivations for autocorrelation functions are carried out precisely. After that, we verified the correctness and accuracy of the theoretical derivation by comparing the derived results with numerical simulations using MATLAB. We also divided the spectrum into four components according to the derivation. By analyzing these figures in the graphic, each component determines the characteristics of the spectrum. It is vital for enhanced spectral characteristics. To more visually represent the energy concentration of the main flap and the roll-down speed of the side flap, the specific out-of-band power of M-ary MSK is given. OMLCD(Optimum Maximum Likelihood Coherent Detection) of M-ary MSK is adopted to compare the signal received with prepared in advance in a code element T to go for the best. And M-ary MSK BER(Bit Error Rate) is compared with the same ary PSK (Phase Shift Keying) with M=2,4,6,8. The results show the detection method could improve performance by increasing the length of L(memory inherent) in the phase continuity.

Effects of environmental temperature and age on the elastic modulus of concrete

Shuzhen Yang,Baodong Liu,Yuzhong Li,Minqiang Zhang 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.6

Concrete mechanical properties change constantly with age, temperature, humidity and the other environmental factors. This research studies the effects of temperature and age on the development of concrete elastic modulus by a series of prism specimens. Elastic modulus test was conducted at various temperatures and ages in the laboratory to examine the effects of temperature and age on it. The experimental results reveal that the concrete elastic modulus decreases with the rise of temperature but increases with age. Then, a temperature coefficient K is proposed to describe the effects of temperature and validated by existing studies. Finally, on the basis of K, analytical models are proposed to determine the elastic modulus of concrete at a given temperature and age. The proposed models can offer designers an approach to obtain more accurate properties of concrete structures through the elastic modulus modification based on actual age and temperature, rather than using a value merely based on laboratory testing.

Long-term development of compressive strength and elastic modulus of concrete

Yang, Shuzhen,Liu, Baodong,Yang, Mingzhe,Li, Yuzhong Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.2

Compressive strength and elastic modulus of concrete are constantly changing with age. In order to determine long-term development of compressive strength and elastic modulus of concrete, an investigation of C30 concrete cured in air conditions was carried out. Changes of compressive strength and elastic modulus up to 975 days were given. The results indicated that compressive strength and elastic modulus of concrete rapidly increased with age during the initial 150 days and then increased slowly. The gain in elastic modulus was slower than that of compressive strength. Then relationships of time-compressive strength, time-elastic modulus and compressive strength-elastic modulus were proposed by regression analysis and compared with other investigations. The trends of time-compressive strength and time-elastic modulus with age agreed best with ACI 209R-92. Finally, factors contributed to long-term development of compressive strength and elastic modulus of concrete were proposed and briefly analyzed.

Long-term development of compressive strength and elastic modulus of concrete

Shuzhen Yang,Baodong Liu,Mingzhe Yang,Yuzhong Li 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.2

Compressive strength and elastic modulus of concrete are constantly changing with age. In order to determine long-term development of compressive strength and elastic modulus of concrete, an investigation of C30 concrete cured in air conditions was carried out. Changes of compressive strength and elastic modulus up to 975 days were given. The results indicated that compressive strength and elastic modulus of concrete rapidly increased with age during the initial 150 days and then increased slowly. The gain in elastic modulus was slower than that of compressive strength. Then relationships of time-compressive strength, time-elastic modulus and compressive strength-elastic modulus were proposed by regression analysis and compared with other investigations. The trends of time-compressive strength and time-elastic modulus with age agreed best with ACI 209R-92. Finally, factors contributed to long-term development of compressive strength and elastic modulus of concrete were proposed and briefly analyzed.

Constructing mixed matrix membranes for CO2 separation based on light lanthanide fluoride nanosheets with mesoporous structure

Yanli Zhang,Meixue Zhao,Xu Li,Qingping Xin,Xiaoli Ding,Lizhi Zhao,Hui Ye,Ligang Lin,Hong Li,Yuzhong Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.125 No.-

The incorporation of porous nano-fillers into mixed matrix membranes (MMMs) has a great impact onCO2 separation. In this study, a series of F-Ln (Ln is the Light Lanthanide, Ln = La, Ce, Pr, Nd) nanosheetswith mesoporous structure was fabricated as a filler in Pebax1657 matrix to improve the performance ofCO2 separation. F-Ln nanosheets are uniformly distributed in the membrane and the mesoporous structurecan construct multiple channels for CO2 fast transport in Pebax/F-Ln MMMs. The pore diameter ofnanosheet is in order: F-La > F-Ce > F-Pr > F-Nd, and the smaller pore diameter of nanosheets is beneficialto improve the CO2 separation performance. In humidified conditions, Pebax/F-Nd-6 MMMs show optimumseparation performance among MMMs, and the CO2 permeability is up to 1265 Barrer and CO2/CH4selectivity is 36.7, which are 2.3 times and 1.9 times higher than pure Pebax and approaches 2019 upperbound. Meanwhile, to demonstrate the potential universal applicability of F-Ln nanosheets in CO2 separation,XLPEO/F-Ce MMMs were fabricated to separate CO2/N2 and the performance exceeds the 2019upper bound. The efficient CO2 separation performance of 2D F-Ln nanosheets with mesoporous structurein membranes reveals the potential application of these nanosheets in industrial CO2 separation.

Adsorption resin/polyethersulfone membrane used for plasma separation and middle molecular toxins adsorption

Xiaoyang Hou,Lilan Huang,Han Zhang,Qingping Xin,Hong Li,Hui Ye,Yuzhong Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.123 No.-

Accumulation of endogenous and exogenous toxins in patients with chronic kidney disease increases thekidney burden. The newly developed plasma separation adsorption membranes provide a new model forthe removal of middle molecular toxins. In this study, the adsorption resin LX-1000H is physically pulverizedand blended into polyethersulfone matrixes to prepare adsorption resin/polyethersulfone (AR/PES) membranes by nonsolvent-induced phase separation for plasma separation and middle moleculartoxins absorption. The results show that the static adsorption capacity of AR/PES membrane for lysozyme(a typical mimic of middle molecular toxins) is up to 108.90 mg/g, which is 4 times that of AR. The maximumdynamic adsorption capacity reaches 102.80 mg/g, which is 93.4% of static adsorption. The adsorptionprocess is more consistent with the Langmuir model and the quasi-first-order kinetic model. Thepermeability of bovine serum albumin in simulated blood surpasses 90% and the cattle blood separatedby AR/PES membrane is colorless and transparent. The AR/PES membrane surface presents electronegativeat pH 7.4 and the water wettability is enhanced with the doping amount. No hemolysis and negligibleleakage indicated favorable hemocompatibility. This paper is devoted to providing a strategy forplasma separation and adsorption membranes.

Impact of sorption functional media (SFM) from zeolite tailings on the removal of ammonia nitrogen in a biological aerated filter

Yan Feng,Yanzhen Yu,Liping Qiu,Yawen Yang,Zhigang Li,Miaowan Li,Lisha Fan,Yuzhong Guo 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

Haydite and sorption functional media (SFM),made of clinoptilolite tailings, were used as filter media forbiological aerated filter (BAF) to treat synthetic wastewater in parallel. The aim of this work was toevaluate impact of SFM on the removal of ammonia nitrogen in a biological aerated filter reactor underammonium nitrogen shock loads. It could be demonstrated that: (1) the BAF with SFMpresented higherammonia nitrogen removal efficiency than that with haydite; (2) during the phase of higher influentconcentrations SFMs were collecting ammonia nitrogen and can buffer ammonia nitrogen loads anddampen the effluent concentration of ammonia nitrogen; (3) when the influent concentration decreasesammonia nitrogen will desorb from the SFM and can be utilized by the nitrifying bacteria growing on theSFM. Therefore, with the SFM application existing BAF unites can be upgraded and the stability of theoperation process of BAF can be improved significantly.