588 research outputs found
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ELECTROMAGNETIC SIMULATIONS AND PROPERTIES OF THE FUNDAMENTAL POWER COUPLERS FOR THE SNS SUPERCONDUCTING CAVITIES*
The Spallation Neutron Source (SNS) makes use of superconducting cavities for the acceleration of negative H ions in the main linac. Two types of 6-cell Niobium cavities are used in the superconducting portion of the linac: 33 {beta}=0.61 cavities and 48 {beta}=0.81 cavities. Each cavity is powered via a coaxial fundamental power coupler (FPC) of a simple yet robust design. The electromagnetic design of the main components of that coupler has been modeled and some of those properties have been measured experimentally. Modeling includes impedance matching of the window and of the waveguide to coaxial doorknob transition; coupling of the coupler fields to the cavity fields; and multipacting behavior of the coaxial line and window. Various aspects of design, simulation, and testing on the coupler and cavity are presented
Dynamic Analysis of a Rotating Shaft Subject to the Double Cutting Force and Time-varying Mass Effects of the Rod
AbstractThis paper investigates the dynamic behaviors of a rotating shaft subjected to the double cutting force and time-varying mass effects. The Timoshenko beam theory is used to model the rotating shaft, and the general boundary condition is assumed as the clamped-hinged supports. This system is used to simulate the manufacture process of the double turret CNC lathes, and the mass of the rod which is reduced gradually in cutting process. The system equations of motion are derived based on the global assumed mode method, and the dynamic responses of the system are obtained by Runge-Kutta numerical method. The transformation matrix is derived to make the equation of motion completing the boundary geometric constraints. The numerical results compare the dynamic response in different moving speeds and skew angles of the cutting forces with/without the time-varying mass effects. Additionally, this paper compares the response with single cutting force and double force. The results show that the double moving force system can reduce not only the machining time but also the amplitude of shaft vibration
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Design of 118 MHz twelfth harmonic cavity of APS PAR
Two radio frequency (RF) cavities are needed in the Positron Accumulator Ring (PAR) of the Advanced Photon Source. One is for the first harmonic frequency at 9.8 MHz, and the other is for the twelfth harmonic frequency at 118 MHz. This note reports on the design of the 118 MHz RF cavity. Computer models are used to find the mode frequencies, impedances, Q-factors, and field distributions in the cavity. The computer codes MAFIA, URMEL, and URMEL-T are useful tools which model and simulate the resonance characteristics of a cavity. These codes employ the finite difference method to solve Maxwell`s equations. MAFIA is a three-dimensional problem solver and uses square patches to approximate the inner surface of a cavity. URMEL and URMEL-T are two-dimensional problem solvers and use rectangular and triangular meshes, respectively. URMEL-T and MAFIA can handle problems with arbitrary dielectric materials located inside the boundary. The cavity employs a circularly cylindrical ceramic window to limit the vacuum to the beam pipe. The ceramic window used in the modeling will have a wall thickness of 0.9 cm. This wall thickness is not negligible in determining the resonant frequencies of the cavity. In the following, results of two- and three-dimensional modeling of the cavities using the URMEL-T and MAFIA codes are reported
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Feasibility studies of a compact mm-wave linac FEL
Short wavelength FELs impose stringent requirements on the quality of the electron beams. The key factor in obtaining a single-pass UV or x-ray FEL is the generation of small emittance electron beams with ultra-high brightness. The pioneering work at Los Alamos National Laboratory in the last decade has resulted in a dramatic improvement in the production of high electron beam brightness and small beam emittance using rf photocathode gun. The lower bound on the emittance of a 1-nC bunch without any emittance compensation is on the order of 3 {pi} mm-mrad. This is well within the emittance requirement being considered here. Although the original R&D work at Argonne, in collaboration with the University of Illinois at Chicago and University of Wisconsin-Madison, has produced encouraging results in the area of rf structure design, x-ray mask fabrication, and LIGA processing (Lithography, Electroforming, and Molding), the goal to prove feasibility has not yet been achieved. In this paper, we will present feasibility studies for a compact single-pass mm-linac FEL based on LIGA technology. This system will consist of a photocathode rf gun operated at 30 GHz, a 50-MeV superconducting constant gradient structure operated at 60 GHz, and a microundulator with 1-mm period
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An overview of the APS 352-MHz rf systems
The Advanced Photon Source (APS) is a 7-GeV full energy positron storage ring for generating synchrotron radiation with an injector. The booster synchrotron rf system consists o a single 1-MW klystron which drives four five-cell cavities at 352 MHz. The storage ring cavities consist of four groups of four single cells powered by two 1-MW klystrons for 100-mA operation. An overview of the operation of the APS 352-MHz rf systems is presented
Expression profiling of cyclin B1 and D1 in cervical carcinoma
Aim: Cyclins are a family of regulatory proteins that play a key role in controlling the cell cycle. Abnormalities of cell cycle regulators, including cyclins and cyclin dependent kinases, have been reported in various malignant tumors. This study was undertaken to quantitatively detect cyclin B1 and D1 in cervical cancer. Methods: A quantitative real-time reverse transcription polymerase chain reaction and Western blot assay were used to analyze the expression of cyclin B1/D1 mRNA and proteins, respectively, in fresh invasive cervical cancer (n = 41) and normal cervical tissues (n = 10). Results: There was significantly greater cyclin B1 expression in invasive cervical cancer than in normal cervical tissue (P = 0.019). However, cyclin D1 expression was not significantly different. A Western blot assay yielded similar results. Conclusion: Our results were consistent with the concept that up-regulation of cyclin B1 expression occurred in cervical cancer and an aberrant expression of cyclin B1 might play an important role in cervical carcinogenesis.Π¦Π΅Π»Ρ: ΡΠΈΠΊΠ»ΠΈΠ½Ρ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»ΡΡΡ ΡΠΎΠ±ΠΎΠΉ ΡΠ΅ΠΌΠ΅ΠΉΡΡΠ²ΠΎ ΡΠ΅Π³ΡΠ»ΡΡΠΎΡΠ½ΡΡ
Π±Π΅Π»ΠΊΠΎΠ², ΠΊΠΎΠ½ΡΡΠΎΠ»ΠΈΡΡΡΡΠΈΡ
ΠΊΠ»Π΅ΡΠΎΡΠ½ΡΠΉ ΡΠΈΠΊΠ». ΠΠ°Π»ΠΈΡΠΈΠ΅
ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΡΡ
ΠΈ ΡΡΡΡΠΊΡΡΡΠ½ΡΡ
Π½Π°ΡΡΡΠ΅Π½ΠΈΠΉ ΡΠ΅Π³ΡΠ»ΡΡΠΎΡΠΎΠ² ΠΊΠ»Π΅ΡΠΎΡΠ½ΠΎΠ³ΠΎ ΡΠΈΠΊΠ»Π° (ΡΠΈΠΊΠ»ΠΈΠ½ΠΎΠ² ΠΈ ΡΠΈΠΊΠ»ΠΈΠ½Π·Π°Π²ΠΈΡΠΈΠΌΡΡ
ΠΊΠΈΠ½Π°Π·) Π±ΡΠ»ΠΎ
ΠΎΡΠΌΠ΅ΡΠ΅Π½ΠΎ Π² ΠΊΠ»Π΅ΡΠΊΠ°Ρ
ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
Π·Π»ΠΎΠΊΠ°ΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΡ
Π½ΠΎΠ²ΠΎΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΠΉ. Π¦Π΅Π»ΡΡ Π΄Π°Π½Π½ΠΎΠ³ΠΎ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ Π±ΡΠ»ΠΎ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅
ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠ³ΠΎ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΡΠΈΠΊΠ»ΠΈΠ½ΠΎΠ² B1 ΠΈ D1 Π² ΠΊΠ»Π΅ΡΠΊΠ°Ρ
ΡΠ°ΠΊΠ° ΡΠ΅ΠΉΠΊΠΈ ΠΌΠ°ΡΠΊΠΈ. ΠΠ΅ΡΠΎΠ΄Ρ: ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΡΡΠΎΠ²Π½Ρ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ
ΡΠΈΠΊΠ»ΠΈΠ½ΠΎΠ² B1/D1 (mRNA ΠΈ Π±Π΅Π»ΠΊΠΎΠ² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²Π΅Π½Π½ΠΎ) Π² ΡΠ²Π΅ΠΆΠ΅ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ
ΠΊΠ»Π΅ΡΠΊΠ°Ρ
ΠΈΠ½Π²Π°Π·ΠΈΠ²Π½ΠΎΠ³ΠΎ ΡΠ°ΠΊΠ° ΡΠ΅ΠΉΠΊΠΈ ΠΌΠ°ΡΠΊΠΈ (n = 41) ΠΈ
Π½ΠΎΡΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΡΠΊΠ°Π½ΠΈ ΡΠ΅ΠΉΠΊΠΈ ΠΌΠ°ΡΠΊΠΈ (n = 10) ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΠ»ΠΈ ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ RT-PCR Π² ΡΠ΅ΠΆΠΈΠΌΠ΅ ΡΠ΅Π°Π»ΡΠ½ΠΎΠ³ΠΎ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΠΈ ΠΠ΅ΡΡΠ΅ΡΠ½-Π±Π»ΠΎΡ Π°Π½Π°Π»ΠΈΠ·Π°.
Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ: ΠΎΡΠΌΠ΅ΡΠ΅Π½ Π±ΠΎΠ»Π΅Π΅ Π²ΡΡΠΎΠΊΠΈΠΉ ΡΡΠΎΠ²Π΅Π½Ρ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ Π³Π΅Π½Π° ΡΠΈΠΊΠ»ΠΈΠ½Π° Π1 Π² ΠΊΠ»Π΅ΡΠΊΠ°Ρ
ΠΈΠ½Π²Π°Π·ΠΈΠ²Π½ΠΎΠ³ΠΎ ΡΠ°ΠΊΠ° ΡΠ΅ΠΉΠΊΠΈ ΠΌΠ°ΡΠΊΠΈ, ΡΠ΅ΠΌ Π²
ΠΊΠ»Π΅ΡΠΊΠ°Ρ
Π½ΠΎΡΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΡΠΊΠ°Π½ΠΈ (P = 0,019). ΠΠ΅ Π²ΡΡΠ²Π»Π΅Π½Ρ Π·Π½Π°ΡΠΈΡΠ΅Π»ΡΠ½ΡΠ΅ ΡΠ°Π·Π»ΠΈΡΠΈΡ Π² ΡΡΠΎΠ²Π½Π΅ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ Π³Π΅Π½Π° ΡΠΈΠΊΠ»ΠΈΠ½Π° D1. ΠΡΠΈ
ΠΠ΅ΡΡΠ΅ΡΠ½-Π±Π»ΠΎΡ Π°Π½Π°Π»ΠΈΠ·Π΅ ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ Π°Π½Π°Π»ΠΎΠ³ΠΈΡΠ½ΡΠ΅ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ. ΠΡΠ²ΠΎΠ΄Ρ: ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΏΠΎΠ΄ΡΠ²Π΅ΡΠΆΠ΄Π°ΡΡ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠΈΡ
ΠΎΠ± Π°ΠΊΡΠΈΠ²Π°ΡΠΈΠΈ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ ΡΠΈΠΊΠ»ΠΈΠ½Π° Π1 ΠΏΡΠΈ ΡΠ°ΠΊΠ΅ ΡΠ΅ΠΉΠΊΠΈ ΠΌΠ°ΡΠΊΠΈ. ΠΠ±Π΅ΡΡΠ°Π½ΡΠ½Π°Ρ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΡ ΡΠΈΠΊΠ»ΠΈΠ½Π° Π1 ΠΌΠΎΠΆΠ΅Ρ ΠΈΠ³ΡΠ°ΡΡ Π²Π°ΠΆΠ½ΡΡ
ΡΠΎΠ»Ρ ΠΏΡΠΈ Π·Π»ΠΎΠΊΠ°ΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠΉ ΡΡΠ°Π½ΡΡΠΎΡΠΌΠ°ΡΠΈΠΈ ΡΠΏΠΈΡΠ΅Π»ΠΈΡ ΡΠ΅ΠΉΠΊΠΈ ΠΌΠ°ΡΠΊΠΈ
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MM-wave cavity/klystron developments using deep x-ray lithography at the Advanced Photon Source.
Recent microfabrication technologies based on LIGA (German acronym for Li thographe, G alvanoformung, und A bformung) have been applied to build high-aspect-ratio, metallic or dielectric, planar structures suitable for high frequency rf cavity structures. The cavity structures would be used as parts of linear accelerators, microwave undulators, and mm-wave amplifiers. The microfabrication process includes manufacturing of precision x-ray masks, exposure of positive resist by x-rays through the mask, resist development, and electroforming of the final microstructure. Prototypes of a 32-cell, 108-GHz constant impedance cavity and a 66-cell, 94-GHz constant-gradient cavity were fabricated using the synchrotron radiation sources at APS. Preliminary design parameters for a 91- GHz modulator klystron along with an overview of the new technology are discussed
Tracking echovirus eleven outbreaks in Guangdong, China
In April 2019, a suspect cluster of enterovirus cases was reported in a neonatology department in Guangdong, China, resulting in five deaths. We aimed to investigate the pathogen profiles in fatal cases, the circulation and transmission pattern of
the viruses by combining metatranscriptomic, phylogenetic, and epidemiological analyses. Metatranscriptomic sequencing
was used to characterize the enteroviruses. Clinical and environmental surveillance in the local population was performed
to understand the prevalence and genetic diversity of the viruses in the local population. The possible source(s), evolution,
transmission, and recombination of the viruses were investigated by incorporating genomes from the current outbreak,
from local retrospective surveillance, and from public databases. Metatranscriptomic analysis identified Echovirus 11 (E11)
in three fatal cases. Seroprevalence of neutralization antibody to E11 was 35 to 44 per cent in 3β15 age groups of general population, and the viruses were associated with various clinical symptoms. From the viral phylogeny, nosocomial transmissions were identified and all E11 2019 outbreak strains were closely related with E11 strains circulating in local population 2017β19. Frequent recombination occurred among the 2019 Guangdong E11 outbreak strains and various genotypes in enterovirus B species. This study provides an example of combining advanced genetic technology and epidemiological surveillance in pathogen diagnosis, source(s), and transmission tracing during an infectious disease outbreak. The result highlights the hidden E11 circulation and the risk of viral transmission and infection in the young age population in China.
Frequent recombination between Guangdong-like strains and other enterovirus genotypes also implies the prevalence of
these emerging E11 strains
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