全部國産に依る16ミリ「レ」線映晝 : 第2編

<div><p>Microfluidics is a great enabling technology for biology, biotechnology, chemistry and general life sciences. Despite many promising predictions of its progress, microfluidics has not reached its full potential yet. To unleash this potential, we propose the use of intrinsically active hydrogels, which work as sensors and actuators at the same time, in microfluidic channel networks. These materials transfer a chemical input signal such as a substance concentration into a mechanical output. This way chemical information is processed and analyzed on the spot without the need for an external control unit. Inspired by the development electronics, our approach focuses on the development of single transistor-like components, which have the potential to be used in an integrated circuit technology. Here, we present membrane isolated chemical volume phase transition transistor (MIS-CVPT). The device is characterized in terms of the flow rate from source to drain, depending on the chemical concentration in the control channel, the source-drain pressure drop and the operating temperature.</p></div

Long-term changes of tropospheric NO2 over megacities derived from multiple satellite instruments

<p>Conference poster presented at the DOAS workshop in Boulder, CO (Aug 2013).</p

On the use of UV/vis satellite tropospheric data products

Deliverable D5.6 from the EU FP7 project "Partnership with China on Space Data (PANDA)", grant no. 606719, prepared by Institute of Environmental Physics, University of Bremen (IUP-UB)

3D-plot of measured output characteristics (flow rate Q_DS vs. pressure p_DS vs. ethanol concentration c_Eth) of the MIS-CVPT at different temperatures <i>ϑ</i> ranging from 22.5°C to 30.0°C in 2.5K steps.

<p>3D-plot of measured output characteristics (flow rate Q_DS vs. pressure p_DS vs. ethanol concentration c_Eth) of the MIS-CVPT at different temperatures <i>ϑ</i> ranging from 22.5°C to 30.0°C in 2.5K steps.</p

Overview of the fabrication procedure.

<p><b>Master fabrication:</b> (A) Lamination of dry film resist onto substrate. (B) Exposure with UV light through photo mask. (C) Post-exposure bake. (D) Development and rinsing with following hard bake. <b>Chip fabrication</b>: (E) Spin coating of PDMS on control layer master. (F) Moulding of PDMS on flow layer master. <b>Chip assembling</b>: (G) Inhibition of the channel break in the flow layer. (H) Plasma bonding with aligning of the PDMS layers. (I) Incorporation of the hydrogel particle into the control channel. (J) Plasma bonding of the multi-layer chip onto a cover glass.</p

Transfer characteristic of the MIS-CVPT. Flow rate Q_DS over ethanol concentration c_Eth at a constant pressure p_DS = 100mbar for the temperatures <i>ϑ</i> 22.5°C; 25.0°C; 27.5°C; 30.0°C.

<p>Transfer characteristic of the MIS-CVPT. Flow rate Q_DS over ethanol concentration c_Eth at a constant pressure p_DS = 100mbar for the temperatures <i>ϑ</i> 22.5°C; 25.0°C; 27.5°C; 30.0°C.</p

Dynamic investigation of the gate switching.

<p>(A), Experimental approach of the investigation. Switch event at t₀ carried out by a change of the input flow in the control channel from c₀ (= 0wt%) to c₁ (= 30wt%), while applying a constant pressure over the chemo-fluidic transistor. The flow rate generated in the flow channel is measured via a flow sensor. (B), Typical measurement of pressure and flow rate data over time, starting from time t₀ (= 0s). (C), Schematic graph with characteristic parameters to quantify the experimental data. (D), Bar graph of the characteristic parameter t₁₀, t₉₀ and Δt for three different dimensions of gel particles.</p

Measured output characteristics (flow rate Q_DS vs. pressure p_DS) of the MIS-CVPT with the different ethanol concentrations c_<i>Eth</i> 0wt%, 7.5wt%, and 15.0wt% at different temperatures <i>ϑ</i> ranging from 15.0°C to 30.0°C in 5.0K steps.

<p>Measured output characteristics (flow rate Q_DS vs. pressure p_DS) of the MIS-CVPT with the different ethanol concentrations c_<i>Eth</i> 0wt%, 7.5wt%, and 15.0wt% at different temperatures <i>ϑ</i> ranging from 15.0°C to 30.0°C in 5.0K steps.</p

Opening pressure extracted from the measurement data and modeled as a 2nd order 2D polynomial.

<p>Opening pressure extracted from the measurement data and modeled as a 2nd order 2D polynomial.</p

Tetra-Sensitive Graft Copolymer Gels as Active Material of Chemomechanical Valves

Stimuli-responsive hydrogels combine sensor and actuator properties by converting an environmental stimulus into mechanical work. Those materials are highly interesting for applications as a chemomechanical valve in microsystem technologies. However, studies about key characteristics of hydrogels for this application are comparatively rare, and further research is needed to emphasize their real potential. The first part of this study depicts the synthesis of grafted hydrogels based on a poly­(<i>N</i>-isopropylacrylamide) backbone and pH-sensitive poly­(acrylic acid) graft chains. The chosen approach of grafted hydrogels provides the preparation of multiresponsive hydrogels, which retain temperature sensitivity besides being pH-responsive. A pronounced salt and solvent response is additionally achieved. Key characteristics for an application as a chemomechanical valve of the graft hydrogels are revealed: (1) independently addressable response to all stimuli, (2) significant volume change, (3) sharp transition, (4) reversible swelling–shrinking behavior, and (5) accelerated response time. To prove the concept of multiresponsive hydrogels for flow control, a <i>net</i>-poly­(<i>N</i>-acrylamide)-<i>g</i>-poly­(acrylic acid) hydrogel containing 0.6 mol % poly­(acrylic acid)-vinyl is employed as active material for chemomechanical valves. Remarkably, the chemomechanical valve can be opened and closed in a fluidic platform with four different stimuli