**7. References**

40 Advanced Topics in Measurements

02468

1. Regular estimation of the status of the increase in spasticity in specific patients with *F*γ<sup>d</sup>

2. Reduction of individual differences and quantitative assessments of spasticity based on a uniform scale by standardizing inputs values of the pendulum test model for all subjects, under the premise that subject's body type and geometric structure of internal

This article thoroughly discusses a new knee joint motion measurement system constructed using two linear accelerometers, from the basic stretch reflex to the analysis of measurement

In section 2, we first explained the mechanical structure of knee joint flexion and extension as background knowledge to understand the discussion in section 3 and subsequent subsection, briefly touching also on the movement of the knee joint axis. Next, we looked at the source of the generation of the stretch reflex, which is the subject of measurement of the knee joint motion measurement system. We also showed the phasic and tonic reflex loops

In section 3, we summarized the principles and results of performance evaluation of the knee joint motion measurement system. First, we looked comprehensively at accelerometers, which are the best option among sensors that can be used to measure knee joint motion, and then discussed the principles of the knee joint motion measurement system using two linear accelerometers. Next, we showed that the detection error of this device for simple pendulum motion and the pendulum motion of subjects is about the same as with high-accuracy,

In section 4, we showed that the angle and angular acceleration of the knee joint could be simultaneously synchronized and measured in patients showing spasticity with enhanced phasic reflexes, and that the timing at which reflexes are produced could be easily estimated. Next, we showed the principles of a simulator to analyze measured waveforms and examples of analysis using this simulator, together with an additional statement on the

outlook for high-level analysis of reflexes in patients with spasticity.

measurement result

3. Verification of the effect of antispasticity drugs using this system.

simulation result

Fig. 22. Result of inverse simulation of a spastic patient.

results, focused on achievements obtained up to this time.

tissue are considered to be similar.

centered on muscle spindle function.

rotation angle gauges.

time (s)

−60 −40 −20

and *F*i values.

**5. Conclusions** 

0

angular acceleration (rad/s2

)

20 40 60


**3** 

 *Japan* 

**XAFS Measurement System in the Soft X-Ray** 

An X-ray absorption fine structure (XAFS) spectroscopy is a powerful and useful technique to probe the local electronic structure and the local atomic structure around an absorbing atom in an unknown material [Stöhr, 1996, Ohta, 2002]. A highly bright X-ray source, synchrotron radiation (SR) is usually used for XAFS measurements to obtain reliable

For visible/ultraviolet (UV) and infrared absorption spectroscopies, the transmission mode is generally used, where incident and transmitted photon intensities are monitored. This is also the most fundamental technique for XAFS measurements in the hard X-ray region. However, it is hard to apply it in the soft X-ray region because of very low transmission. Instead, other techniques equivalent to the transmission mode have been developed; total/partial electron yield (EY) and fluorescent yield (FY) modes. The former is a widely adopted mode in the soft X-ray region, where the yield of Auger electrons and/or secondary electrons is proportional to the X-ray absorption coefficient. Since the electron escape depth is very short, the EY mode is surface sensitive. The latter is useful for XAFS measurement of heavy elements of low concentration in the hard X-ray region, and it is also useful as a bulk sensitive method in the soft X-ray region, although the probability of radiative decay is much smaller than that of Auger decay. It is often the case that an appropriate mode is

We have developed a practical and useful XAFS measurement system in the soft X-ray region applicable for various sample conditions and multipurpose measurements. In this system, it is possible to measure not only solid samples (such as powder, grain, sheet and thin film samples) but also liquid and gel samples. It is also applicable to in-situ measurements of anaerobic samples. In addition, it provides us some information of depth

The XAFS measurement system is an assembly of several components; a soft X-ray beamline, sample chambers, detection systems, and a sample transfer system. Details of

spectra, even for elements of very low content in a sample.

profiles with combined use of the EY and FY modes.

each component are described follow.

**2. XAFS measurement system in the soft X-ray region** 

**1. Introduction** 

chosen for sample conditions.

**Region for Various Sample Conditions** 

 **and Multipurpose Measurements** 

Koji Nakanishi and Toshiaki Ohta *The SR Center, Ritsumeikan University,* 

