Abstract: The tension of a strip can be controlled with high responsiveness and high accuracy despite its drastic external variation by threading the strip (1) between a transportation roll (2) and a movable transportation roll (10) and moving the movable transportation roll (10). The movable transportation roll (10) is mounted on one end of an arm (11), which is mounted for a swing motion around a supporting shaft (12), a torque around the supporting shaft (12) is generated in the arm (11) by an arm driving motor (14) connected directly to the supporting shaft (12), thereby applying a tension to the strip (1). The angle of swing motion of the arm (11) is detected by an arm angle sensor (16), and the tension of the strip (1) is detected by a tension sensor (15). The torque to be generated in the arm (11) is corrected in accordance with the detected angle and tension, whereby the strip tension is controlled for a target tension.

Abstract: The invention provides an apparatus for plasma separation/exchange by double-step-membrane filtration, namely separation of blood into plasma and a corpuscular fraction and separation of high-molecular-weight substances (e.g. gamma-globulin) in the plasma from low-molecular-weight substances (e.g. albumin), and addition of a substitute fluid. A method of treating blood is also provided.The apparatus and method are effective e.g. in the treatment of blood of patients with peripheral circulatory insufficiency due to arteriosclerosis and of patients with rheumatoid arthritis, which is an autoimmune disease.

Abstract: A tuner comprises a local oscillator including a variable capacitance diode. The output signal of the local oscillator is frequency divided by a prescaler and the frequency divided output is applied to a phase locked loop. The phase locked loop is structured such that the phases of the output signal of the prescaler and a reference frequency signal are compared and the signal associated with the phase difference is smoothed by a low pass filter and the smoothed output is applied to the variable capacitance diode as a tuning voltage. The low pass filter includes a smoothing capacitor. A tuning unlocked state is detected when the terminal voltage of the smoothing capacitor is stabilized at the source voltage or is stabilized at 0V.