Novel Filtering Power Divider with External Isolation Resistors

Yun Long Lu,Shun Wang,Gao-Le Dai,Kai Li 한국전자통신연구원 2015 ETRI Journal Vol.37 No.1

In this paper, a novel filtering power divider with external isolation resistors is presented. The proposed power divider can be considered as an integration of a bandpass filter and a Gysel power divider. Based on the circuit topology, a high-order filtering power divider can be easily realized. Odd- and even-mode models are employed to analyze the filtering and power splitting functions. For demonstration, a third-order filtering power divider operating at 1.5 GHz is designed and implemented. The measured results exhibit an isolation between the output ports that is better than 20 dB at around the center frequency.

A Novel Unequal Broadband Out-of-Phase Power Divider Using DSPSLs

Yun Long Lu,Gao-Le Dai 한국전자통신연구원 2014 ETRI Journal Vol.36 No.1

In this paper, a novel unequal broadband out-of-phasepower divider (PD) is presented. Double-sided parallelstriplines (DSPSLs) are employed to achieve an out-ofphaseresponse. Also, an asymmetric dual-band matchingstructure with two external isolation resistors is utilized toobtain arbitrary unequal power division, in which theresistors are directly grounded for heat sinking. A throughground via (TGV), connecting the top and bottom sides ofthe DSPSLs, is used to short the isolation components. Additionally, this property can efficiently improve thebroadband matching and isolation bandwidths. Toinvestigate the proposed divider in detail, a set of designequations are derived based on the circuit theory andtransmission line theory. The theoretical analysis showsthat broadband responses can be obtained as properfrequency ratios are adopted. To verify the proposedconcept, a sample divider with a power division of 2:1 isdemonstrated. The measured results exhibit a broadbandwidth from 1.19 GHz to 2.19 GHz (59.2%) with areturn loss better than 10 dB and port isolation of 18 dB.

전동트라이볼러지 설계에 관한 연구

韋雲隆(Yun-long Wei),류성기(Sung-ki Lyu),盧龍(Long-Lu),정광조(Kwang-jo Jung),임주석(Ju-suck Lim),曺興進(Xing-jin Cao) 한국트라이볼로지학회 2003 한국윤활학회지(윤활학회지) Vol.19 No.4

Study on flow characteristics in LBE-cooled main coolant pump under positive rotating condition

Lu Yonggang,Wang Zhengwei,Zhu Rongsheng,Wang Xiuli,Long Yun 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.7

The Generation IV Lead-cooled fast reactor (LFR) take the liquid lead or lead-bismuth eutectic alloy (LBE) as the coolant of the primary cooling circuit. Combined with the natural characteristics of lead alloy and the design features of LFR, the system is the simplest and the number of equipment is the least, which reflects the inherent safety characteristics of LFR. The nuclear main coolant pump (MCP) is the only power component and the only rotating component in the primary circuit of the reactor, so the various operating characteristics of the MCP are directly related to the safety of the nuclear reactor. In this paper, various working conditions that may occur in the normal rotation (positive rotating) of the MCP and the corresponding internal flow characteristics are analyzed and studied, including the normal pump condition, the positive-flow braking condition and the negative-flow braking condition. Since the corrosiveness of LBE is proportional to the fluid velocity, the distribution of flow velocity in the pump channel will be the focus of this study. It is found that under the normal pump condition and positive-flow braking conditions, the high velocity region of the impeller domain appears at the inlet and outlet of the blade. At the same radius, the pressure surface is lower than the back surface, and with the increase of flow rate, the flow separation phenomenon is obvious, and the turbulent kinetic energy distribution in impeller and diffuser domain shows obvious near-wall property. Under the negative-flow braking condition, there is obvious flow separation in the impeller channel.

NH₂-Fe-MILs for effective adsorption and Fenton-like degradation of imidacloprid: Removal performance and mechanism investigation

Mao-Long Chen,Tian-Hui Lu,Ling-Li Long,Zhou Xu,Li Ding,Yun-Hui Cheng 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.2

This investigation enables amino-functionalized metal–organic frameworks (MOFs) materials for the removal of imidacloprid (IMC). Two Fe-based MOF materials of NH₂-MIL-88B(Fe) and NH₂-MIL-101(Fe) both exhibited high adsorption capacity and Fenton-like degradation ability for IMC which were utilized to remove IMC from aqueous solution. Although the adsorption capacity of NH₂-MIL-101(Fe) was higher than that of NH₂-MIL-88(Fe), the degradation abilities of both MOF materials were similar. The removal efficiencies were evaluated through several basic studies, including concentrations of catalyst (0.12-0.3 g/L) and IMC (20-100 mg/L), pH of solution (3-11), and amounts of 30% H₂O₂ (0-2.0 μL/mL). By optimizing the above factors, the total removal ratio of IMC by NH₂-MIL-88B(Fe) was as high as 93%, whereas the removal ratio of NH₂-MIL-101(Fe) was 97%. Moreover, these MOF materials were proven to be stable and recyclable. The free radical quenching experiment and density functional theory calculation were applied to research the removal mechanism, and the hydroxyl radicals (·OH) was found to be the key active intermediate. The high catalytic efficiency can be attributed to the synergy of the Fe<SUP>3+</SUP>/Fe<SUP>2+</SUP> redox cycle.

Heavy concrete shielding properties for carbon therapy

Jin-Long Wang,Jiade J Lu,Da-Jun Ding,Wen-Hua Jiang,Ya-Dong Li,Rui Qiu,Hui Zhang,Xiao-Zhong Wang,Huo-Sheng Ruan,Yan-Bing Teng,Xiao-Guang Wu,Yun Zheng,Zi-Hao Zhao,Kai-Zhong Liao,Huan-Cheng Mai,Xiao-Dong Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.6

As medical facilities are usually built at urban areas, special concrete aggregates and evaluation methods are needed to optimize the design of concrete walls by balancing density, thickness, material composition, cost, and other factors. Carbon treatment rooms require a high radiation shielding requirement, as the neutron yield from carbon therapy is much higher than the neutron yield of protons. In this case study, the maximum carbon energy is 430 MeV/u and the maximum current is 0.27 nA from a hybrid particle therapy system. Hospital or facility construction should consider this requirement to design a special heavy concrete. In this work, magnetite is adopted as the major aggregate. Density is determined mainly by the major aggregate content of magnetite, and a heavy concrete test block was constructed for structural tests. The compressive strength is 35.7 MPa. The density ranges from 3.65 g/cm³ to 4.14 g/cm³, and the iron mass content ranges from 53.78% to 60.38% from the 12 cored sample measurements. It was found that there is a linear relationship between density and iron content, and mixing impurities should be the major reason leading to the nonuniform element and density distribution. The effect of this nonuniformity on radiation shielding properties for a carbon treatment room is investigated by three groups of Monte Carlo simulations. Higher density dominates to reduce shielding thickness. However, a higher content of high-Z elements will weaken the shielding strength, especially at a lower dose rate threshold and vice versa. The weakened side effect of a high iron content on the shielding property is obvious at 2.5 µSv=h. Therefore, we should not blindly pursue high Z content in engineering. If the thickness is constrained to 2 m, then the density can be reduced to 3.3 g/cm³, which will save cost by reducing the magnetite composition with 50.44% iron content. If a higher density of 3.9 g/cm³ with 57.65% iron content is selected for construction, then the thickness of the wall can be reduced to 174.2 cm, which will save space for equipment installation.

A study on the transmission-tribology design based on existing problem of the gear drive and tribology

Sung-Ki Lyu,Long Lu,Yun-Long Wei 한국정밀공학회 2006 International Journal of Precision Engineering and Vol.7 No.2

We propose a new concept of transmission-tribology design based on the investigation of development and existing problems of the gear drive and tribology. The content of transmission-tribology and transmission-tribology design is probed. Some effective methods of transmission-tribology design is probed. Some effective methods of transmission-tribology design are putforward. Partial achievements in this research are introduced tersely. Mechanical transmission, which is represented by the gear drive, and tribology are two main branches of mechanical engineering. They have their own definite research field. In recent years, we have been doing our utmost to suggest combining mechanical transmission-tribology and transmission-tribology design. Partial achievements in this research area are obtained.

A Study on the Transmission-tribology Design Based on Existing Problem of the Gear Drive and Tribology

Lyu, Sung-Ki,Lu, Long,Wei, Yun-Long Korean Society for Precision Engineering 2006 International Journal of Precision Engineering and Vol.7 No.2

We propose a new concept of transmission-tribology design based on the investigation of development and existing problems of the gear drive and tribology. The content of transmission-tribology and transmission-tribology design is probed. Some effective methods of transmission-tribology design is probed. Some effective methods of transmission-tribology design are put forward. Partial achievements in this research are introduced tersely. Mechanical transmission, which is represented by the gear drive, and tribology are two main branches of mechanical engineering. They have their own definite research field. In recent years, we have been doing our utmost to suggest combining mechanical transmission-tribology and transmission-tribology design. Partial achievements in this research area are obtained.

CD64 Expression Is Increased in Patients with Severe Acute Pancreatitis: Clinical Significance

( Hao Zhang ),( Xian Long Ling ),( Yu Yun Wu ),( Mu Han Lu ),( Hong Guo ),( Peng Bin Zhang ),( Xiao Yan Zhao ),( Shi Ming Yang ) 대한소화기학회 2014 Gut and Liver Vol.8 No.4

Background/Aims: Upregulated CD64 expression on neutrophils is the most useful marker for acute bacterial infections and systemic inflammation. However, it is unknown whether CD64 is involved in the pathogenesis of acute pancreatitis (AP). This study was designed to determine whether CD64 is implicated in severe acute pancreatitis (SAP), and thus, is a suitable marker for SAP. Methods: SAP was induced in rats with an intraperitoneal injection of L-arginine. CD64 expression in the rat pancreas was determined by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry. Additionally, the CD64 mRNA expression in peripheral blood leukocytes from 21 patients with mild acute pancreatitis (MAP) and 10 patients with SAP was investigated at the time of admission and during remission by qRT-PCR. Results: CD64 mRNA and protein expression in the pancreas was significantly higher in rats with SAP, compared to the controls. The CD64 expression was higher in the patients with SAP than in the patients with MAP. During remission, CD64 mRNA decreased in both the MAP and SAP patients. The area under the curve of CD64 expression for the detection of SAP was superior to both the Ranson and the Acute Physiology and Chronic Health Evaluation II scores. Conclusions: The CD64 level was significantly increased in correlation with the disease severity in SAP and may act as a useful marker for predicting the development of SAP. (Gut Liver 2014;8:445-451)