In situ observation of synthesized nanoparticles in ultra-dilute aerosols via X-ray scattering

In-air epitaxy of nanostructures (Aerotaxy) has recently emerged as a viable route for fast, large-scale production. In this study, we use small-angle X-ray scattering to perform direct in-flight characterizations of the first step of this process, i.e., the engineered formation of Au and Pt aerosol nanoparticles by spark generation in a flow of N₂ gas. This represents a particular challenge for characterization because the particle density can be extremely low in controlled production. The particles produced are examined during production at operational pressures close to atmospheric conditions and exhibit a lognormal size distribution ranging from 5–100 nm. The Au and Pt particle production and detection are compared. We observe and characterize the nanoparticles at different stages of synthesis and extract the corresponding dominant physical properties, including the average particle diameter and sphericity, as influenced by particle sintering and the presence of aggregates. We observe highly sorted and sintered spherical Au nanoparticles at ultra-dilute concentrations (< 5 × 10⁵ particles/cm³) corresponding to a volume fraction below 3 × 10^–10, which is orders of magnitude below that of previously measured aerosols. We independently confirm an average particle radius of 25 nm via Guinier and Kratky plot analysis. Our study indicates that with high-intensity synchrotron beams and careful consideration of background removal, size and shape information can be obtained for extremely low particle concentrations with industrially relevant narrow size distributions.

     

爱立信IMS weShare分享每一天(系列之二)如何提供出色的用户体验?

爱立信IMS weShare业务有20%的开发与用户视觉体验相关(用户界面、图标、标签以及进度条),其它的80%则主要致力于设备间的系统.与此相对比,用户的体验则完全(100%)有赖于其可接触的事物.     

A new method for manufacturing nanostructured electrodes on glass substrates

The present paper describes a new method for manufacturing a nanostructured porous layer of TiO₂ on a conducting glass substrate for use in a dye-sensitized photoelectrochemical cell. The method involves deposition of a layer of semiconductor particles onto a conducting substrate and compression of the particle layer to form a mechanically stable, electrically conducting, and porous nanostructured film at room temperature. Photoelectrochemical characteristics and morphology of the resulting nanostructured films are presented. The potential use of the new manufacturing method in the future applications of nanostructured systems is discussed.     

New CAMAC based data acquisition and beam control system for Lund nuclear microprobe

A new CAMAC based data acquisition system has been installed at the Lund Nuclear Microprobe facility. This paper reports on the development and present status of the data acquisition system. The system is a true multiparameter CAMAC based system with fast Fera bus readout and in crate memory buffer. The user interface is based on Sparrow Kmax software for a Power Macintosh platform. The system read out and tag the event data with position on-line, which make fast on-line monitoring of spectra or element maps possible.Simultaneously, all data can be saved event by event for off-line analysis. The beam scanning part is software controlled through a timed D/A converter, this allows fast scanning of the beam. With a CCD-camera and video card the area to be analysed could be defined directly from the image, and the sample position can be moved. Any kind of irregular scan patterns could be defined.     

Copper malabsorption in coeliac disease

Copper uptake during three hours from an oral test dose of copper sulphate solution giving three mg Cu++, close to the recommended daily dietary intake, was significantly reduced in patients with proximal intestinal disease, compared with normal subjects. Three out of ten patients had abnormal and otherwise unexplained blood counts compatible with the known haematological effects of copper deficiency and were restored to normal levels on a gluten-free diet. Copper deficiency and proximal intestinal disease should be suspected in patients with otherwise unexplained anaemia, especially neutropenia.     

Postural and symptomatic improvement after physiotherapy in patients with dizziness of suspected cervical origin

OBJECTIVE: To assess postural performance in patients with dizziness of suspected cervical origin in whom extracervical causes had been excluded, and to assess the effects of physiotherapy on postural performance and subjective complaints of neck pain and dizziness. DESIGN: Prospective, randomized, controlled trial. SETTING: Primary care centers and a tertiary referral center. PATIENTS AND SUBJECTS: Of 65 referrals, 43 patients were excluded because extracervical etiology was suspected. Of the remaining 22 patients, 17 completed the study (15 women, 2 men, x age 37 yr, range 26-49). The controls were 17 healthy subjects (15 women, 2 men, x age 36 yr, range 25-55). INTERVENTION: Physiotherapy based on analysis of symptoms and findings, and aimed to reduce cervical discomfort. Patients were randomized either to receive immediate physiotherapy (n = 9), or to wait 2 months, undergo repeat measurements, and then receive physiotherapy (n = 8). MAIN OUTCOME MEASURES: Posturography, measuring velocity and variance of vibration-induced body sway and variance of galvanically induced body sway. Subjective intensity of neck pain (Visual Analog Scale ratings, 0-100), intensity and frequency of dizziness (subjective score 0-4). RESULTS: The patients manifested significantly poorer postural performance than did healthy subjects (.05 > p > .0001). Physiotherapy significantly reduced neck pain and intensity and the frequency of dizziness (p < .01), and significantly improved postural performance (.05 > p > .0007). CONCLUSIONS: Patients with dizziness of suspected cervical origin are characterized by impaired postural performance. Physiotherapy reduces neck pain and dizziness and improves postural performance. Neck disorders should be considered when assessing patients complaining of dizziness, but alternative diagnoses are common.     

Dynamics of lung collapse and recruitment during prolonged breathing in porcine lung injury

Oleic acid (OA) injection, lung lavage, and endotoxin infusion are three commonly used methods to induce experimental lung injury. The dynamics of lung collapse and recruitment in these models have not been studied, although knowledge of this is desirable to establish ventilatory techniques that keep the lungs open. We measured lung density by computed tomography during breath-holding procedures. Lung injury was induced with OA, lung lavage, or endotoxin in groups of six mechanically ventilated pigs. After a stabilization period, repetitive computed tomography scans of the same slice were obtained during prolonged expirations with and without positive end-expiratory pressure and during prolonged inspirations after 5 and 30 s of expiration. Lung collapse and recruitment occurred mainly within the first 4 s of breath-holding procedures in all three lung injury models, and some collapse and recruitment occurred even within 0.6 s. OA-injured lungs were significantly more unstable than lungs injured by bronchoalveolar lavage or endotoxin infusion. In this experimental setting, expiration times <0.6 s are required to avoid cyclic alveolar collapse during mechanical ventilation without extrinsic positive end-expiratory pressure.