High-sensitivity far-forward collective scattering diagnostic on HL-2A tokamak.

The multichannel formic acid (HCOOH, λ = 432.5 µm) laser interferometer and Faraday-effect polarimeter on HL-2A tokamak have been developed to measure the far-forward collective scattering from electron density fluctuations. The far-forward collective scattering system provides eight channels of line-integrated electron density fluctuations, covering the wave-number range: k⊥ < 1.6 cm-1. With the new diagnostic, the density fluctuations caused by plasma energetic particles and turbulence have been routinely observed in HL-2A experiments.

A new dispersion interferometer on HL-2A.

In order to avoid a fringe jump caused by high plasma density and pellet injection [Y. Zhou et al., Rev. Sci. Instrum. 87, 11E107 (2016)], a new CO2 dispersion interferometer is designed and commissioned on HL-2A for average line-density measurement and density feedback control. The second harmonic technology in this system eliminates the phase shift caused by mechanical vibration. Signals are processed by a digital phase comparator and can be monitored in real time. A series of experiments are conducted to study the characteristics of the system such as a second harmonic coefficient and long-term stability. The resolution of density measurement is less than 8 × 1017/m3, and the experiment result on HL-2A demonstrates the interferometer's capability to track plasma density evolution with rapid change. The system also shows good stability against mechanical vibrations.

[Anomalous systemic arterial supply to normal basal segments of the lower lobe: three cases reports and literature review].

Objective: To improve the clinical recognition of anomalous systemic arterial supply to normal basal segments of the lower lobe in clinical manifestations, diagnosis and treatment. Methods: Three cases were presented and related literatures were reviewed. A literature review was performed with"anomalous systemic arterial supply to normal lower lobe of the lung","anomalous systemic arterial supply to normal basal segments of the lower lobe"and"anomalous systemic arterial supply to normal basal segments of the left lower lobe of the lung"as key words in Pubmed, Embase, Ovid, Wanfang database and CNKI. Result: Our 3 cases were male, with an average age of 36 years old; all of them were admitted with hemoptysis. Left lower lobectomy was performed in 2 cases, and the other 1 case underwent endovascular embolization. 26 related articles were retrieved and our 3 cases were included in this study with a total of 57 cases. The ratio of male to female was 2∶1 (38∶19), with an average age of about 35 years old. The most common symptom was hemoptysis (26/57), followed by asymptomatic (22/57). The main treatments included left lower lobectomy (17/47) and endovascular embolization of anomalous systemic artery (13/47). Conclusions: This disease is more common in male, and the most common symptom is hemoptysis. When chest CT scan shows a nodular retrocardiac density with hemoptysis symptom, clinicians and radiologists should raise suspicion of anomalous systemic arterial supply to normal basal segments of the lower lobe. Chest contrast-enhanced CT scan is an appropriate imaging method to confirm diagnosis. The main treatments include left lower lobectomy and endovascular embolization. For asymptomatic patient, observation may be an acceptable option.

A new high sensitivity far-infrared laser interferometer for the HL-2A tokamak.

A new four-chord Michelson-type formic acid (HCOOH, λ = 432.5 µm) laser interferometer has been successfully commissioned on the HL-2A tokamak to measure the electron density and density fluctuations. Due to the employment of the two-laser heterodyne technique, the time resolution of the interferometer reached 1.0 microseconds (µs). Four chords of line electron densities with a line-averaged density resolution 2 × 1016/m3 were obtained in a recent HL-2A experimental campaign, and detailed electron density fluctuations, caused by events such as edge localized mode, sawtooth precursor-oscillations, and energetic particle driven instabilities, were distinctly measured. In particular, the high-frequency electron density fluctuations (up to 500 kHz) caused by the reversed shear Alfvénic eigenmode were observed by the internal two interferometry channels, and their fluctuation location could be approximately identified from the spectra characteristics of multi-chord line electron densities.

The conceptual design of interferometer/polarimeter system on HL-2M.

HL-2M is a new medium-sized tokamak with major radius of 1.78 m, minor radius of 0.65 m, and aspect ratio of 2.8 and will be finished soon. In the conceptual design, a double-pass, horizontal view, multi-channel far-infrared (FIR) laser interferometer/polarimeter system (at 432 µm) is proposed to simultaneously measure the phase change and the Faraday rotation for density and current profile reconstruction. A vertical CO2 dispersion interferometer system (with wavelength of 10.6 µm and 5.3 µm) is designed to measure the line density, which will mainly be used for density feedback. The performance of the system is expected to meet the requirement of the measurements on HL-2M, with phase accuracy ∼0.1°, time resolution ∼1 µs, spatial resolution ∼7.2 cm, and density measurement range of 1 × 10 18-1 ×1021 m-3.

[A study of the diagnostic value of endobronchial ultrasound guide sheath transbronchial lung biopsy combined with virtual bronchoscopic navigation in peripheral pulmonary lesions].

OBJECTIVE: To evaluate the diagnostic value of endobronchial ultrasound guide sheath transbronchial lung biopsy (EBUS-GS-TBLB) combined with virtual bronchoscopic navigation (VBN) in peripheral pulmonary lesions (PPLs). METHODS: Cases with a PPL identified by computed tomography in Affiliated Hospital of Medical College of Ningbo University underwent EBUS-GS-TBLB with or without VBN randomly between Nov. 2014 to Aug. 2015. X-ray guidance was not performed in these cases. The sensitivity and the operation time were evaluated in the 2 groups. RESULTS: A total of 184 patients were enrolled and completed this study. Among them 117 were males and 67 were females. There were 93 cases in the group of EBUS-GS-TBLB with VBN, and 91 in the group without VBN. The diagnostic sensitivity of VBN group was 72.04%(67/93). Among these positive cases, 64.1% cases (43/67) were malignant tumors, and 35.9% cases (24/67) were benign lesions. The mean operation time was (45±10)min. In the group without VBN, the diagnostic sensitivity was 69.23%(63/91), including 33 malignant tumors(52.4%, 33/63), and 30 benign lesions(47.6%, 30/63). The mean operation time was (55±10)min. There was no significant difference between EBUS-GS-TBLB with VBN group and EBUS-GS-TBLB without VBN group in diagnostic sensitivity (χ(2)=0.175, P=0.747). But there was a significant difference in the mean operation time between the 2 groups (t=6.522, P<0.001). EBUS-GS-TBLB was well tolerated. No severe procedure-related complications such as pneumothorax and hemoptysis were observed. CONCLUSION: VBN cannot improve the diagnostic sensitivity, but it can clear the location of lesion, and shorten the operation time. This technique helps to abandon the X-ray guidance. EBUS-GS-TBLB combined with VBN is a safe and effective technique for PPLs.

Multi-channel far-infrared HL-2A interferometer-polarimeter.

An HL-2A interferometer is upgraded to a multi-channel interferometer∕polarimeter, which includes four chords for the interferometer and four chords for the polarimeter. The far-infrared lasers (at λ = 432.5 µm and 30 mW power) are used to probe plasmas horizontally in the midplane of HL-2A. A conventional heterodyne technique is used for the interferometer. Two counter-rotating circularly polarized waves are used to measure the Faraday rotation effect. A fast-phase comparator with temporal resolution of 1 µs and phase resolution 0.1° is developed. Further, the distortion of the polarization caused by the beam-splitters and the other optical components is also investigated.

A new multichannel interferometer system on HL-2A.

A new multichannel HCN interferometer has been developed on HL-2A tokamak, which is characterized by two techniques: (1) the wave-guide HCN laser with cavity length of 6 m to increase the optical resource power and (2) high response room temperature waveguide Schottky diode detectors to obtain good beat signal. The space resolution is 7 cm by the use of focusing metal mirrors mounted on the vacuum chamber and a compensated optical system. In the 2006 experiment campaign, this new interferometer has been applied for plasma density profile and density sawtooth measurement.