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An in-situ cosmic-dust instrument called the Mercury Dust Monitor (MDM) had been developed as a part of the science payload for the Mio (Mercury Magnetospheric Orbiter, MMO) stage of the joint European Space Agency (ESA)–JAXA Mercury-exploration mission. The BepiColombo spacecraft was successfully launched by an Ariane 5 rocket on October 20, 2018, and commissioning tests of the science payload were successfully completed in near-earth orbit before injection into a long journey to Mercury. MDM has a sensor consisting of four plates of piezoelectric lead zirconate titanate (PZT), which converts the mechanical stress (or strain) induced by dust-particle impacts into electrical signals. After the commencement of scientific operations, MDM will measure the impact momentum at which dust particles in orbit around the Sun collide with the sensor and record the arrival direction. This paper provides basic information concerning the MDM instrument and its predicted scientific operation as a future reference for scientific articles concerning the MDM’s observational data.

Note: International editorial committee (IECBSHM), Duan C.G., chairman, Boldy P.A., secretary Reference Record created on 2004-09-07, modified on 2016-08-08

著者人数：13名, Accepted: 2008-08-19, 資料番号: SA1001037000

A cosmic dust monitor for use onboard a spacecraft is currently being developed using a piezoelectric lead zirconate titanate element (PZT). Its characteristics of the PZT sensor is studied by ground-based laboratory impact experiments using hypervelocity particles supplied by a Van de Graaff accelerator. The output signals obtained from the sensor just after the impact appeared to have a waveform that was explicitly related to the particle’s impact velocity. For velocities less than ∼6 km/s, the signal showed an oscillation pattern and the amplitude was proportional to the momentum of the impacting particle. For higher velocities, the signal gradually changed to a single waveform. The rise time of this single waveform was proportional to the particle’s velocity for velocities above ∼6 km/s. The present paper reports on results for the low velocity case and especially discusses the effect of an outer coating of the sensor with a paint, which is used to reduce heating by solar radiation.

For promoting mobility of engineers across borders, there must be frameworks to recognize the equivalence of engineering education and professional registration. The first gate to the mutual recognition is to share common concepts on the relevant matters. In Japan, the image of engineers is almost equivalent to that of engineering practitioners in general. What we have to do first is to revise the public concept of engineers so that the gap between ours and global ones diminishes. International Engineering Meeting has been discussing problems of education and registration and proposed global standards that would be included in the rules and procedures. Concepts and understandings behind the proposal are compared with ours and the measures for improving our global compatibility are discussed.

A cosmic dust detector using piezoelectric lead zirconate titanate (PZT) is currently being developed for use onboard a spacecraft for the BepiColombo mission. The characteristics of the PZT detector were studied by carrying out hypervelocity impact measurements with iron particles supplied by a Van de Graaff accelerator. The measurements with particle velocities of less than 5 km/s showed a linear relationship between the output voltages obtained from the detector and the particle momenta. This linear relationship obtained was almost independent of the impact angle between the particle and the PZT surface.

A cosmic dust detector for use onboard a satellite is currently being constructed from piezoelectric lead zirconate titanate (PZT). The characteristics of the PZT detector were studied by bombarding it with hypervelocity iron particles, which were supplied by a Van de Graaff accelerator. There was a linear relationship between the rise time of the signal observed from the detector and the particle's velocity, which was above 10 km/s on impact. It was also found that the rise time was almost independent of the collisional angle between the particles and the PZT surface within the limits of the particle's parameters used in this experiment.

The propagation of transverse waves generated acoustically in a piezoelectric element by colliding it with hypervelocity microparticles was studied. The propagation times were measured by a set of multiple electrodes on the surface of the element. The coordinates that the particles struck were determined by combining the propagation times and the velocity of the waves. By using the position-sensitive element, significant deviations between the prior indicated and actually measured orbits were observed. The potential of the present element as part of a steering system is discussed.

The detector characteristics of a pentagonal element were studied by colliding it with hypervelocity micro-particles. A charge-sensitive amplifier was developed for the element of its capacitance ∼10 nF. The output amplitudes were expressed as a linear function of the momentum at collision. Empirical formulas obtained from on-ground experiments could be used for the calibration of the detector. The pentagonal element was potential to measure the momentum during collision from the output amplitude. A set of electrodes on the surface was used to confirm the measurement of the coordinates at collision. A possible application of this pentagonal element on a real-time dust detector was discussed.

著者人数: 14名, 資料番号: SA1003696000

著者人数: 18名, 資料番号: SA1003695000

Before launching the reform and opening-up policy at the end of 1970s, China as a large economy was historically a self-sufficient and inward-oriented country. The People’s Republic of China (PRC) was founded with these legacies in October 1949, and as a socialist country took a cautious stance to participating inthe international division of labor dominated by advanced capitalist countries. One year later, China joined the Korean War in October 1950. As a result, the United Nations imposed an economic embargo upon China, and thus it was practically impossible for China to get into the international economic system. In the 1960s, after China was confronted with the Soviet Union, from which it had received invaluable economic assistance in the previous decade, it suffered a heavy burden of loan repayments to the former alliance partner. These historical experiences led China toward isolation from the outside world and adoption of zili gengshen (self-reliance) policy. Implementing the reform and opening-up policy, therefore, must be an unprecedentedly drastic policy change since the founding of the PRC. In the early 1980s, China’s reform and opening-up policy started with establishing four special economic zones in Guangdong (Shenzhen, Zhuhai and Shantou) and Fujian (Xiamen) to attract FDI. These zones served as an entry point for the acceptance of foreign capital and technology, a base for export processing, and an experimental site for capitalist economic management. Foreign business could enjoy preferential tax treatment while both the central and local governments invested in infrastructure in these zones. In addition to attracting FDI, the Chinese government also sought financing from foreign governments and international financial institutions in the form of official development assistance (ODA) and other loans. In 1984, 14 cities such as Dalian, Tianjin, Shanghai, Guangzhou and other major coastal cities were opened to foreign capital. In the second half of the 1980s, Changjiang or Yangtze River (Shanghai, Jiangsu and Zhejiang), Zhujiang or Pearl River (Guangdong), Minnan (Fujian) Deltas, and Liaodong and Shandong Peninsulas were for the entire region opened to foreign business. In 1992, the upper and middle areas along the Yangtze River, border cities and major inland cities followed suit. China thus reached the final phase of “all-round and multidimensional opening-up” by opening up the whole country to FDI from abroad. China has been successful in attracting foreign capital, and is currently the second largest host country of FDI in the world, absorbing over $100 billion annually since 2010. The FDI accounted for more than 15 percent of total investment in fixed assets in the mid-1990s, and since then has directly contributed to increases in industrial production, employment, tax revenue and foreign trade in China. In general, FDI takes the form of transfer of managerial resources which include knowledge, production technology, management know-how, marketing experience, human skill, intellectual property, market status, informationgathering ability, and research and development (R&D) capacity. FDI has extensively raised the productivity of Chinese industries through the spill-over effects on them. Getting into the twenty-first century, Chinese firms began to invest abroad on a massive scale in response to the government policy of zouchuqu (going-out) in search for new market opportunities, natural resources and strategic assets including key technologies, international brands and sales outlets. In 2013, a236 H. Ohashitotal of 95 Chinese companies were listed in the Fortune Global 500, ranking second after the United States (Renmin Ribao, July 9, 2013). Being typically seen in three major oil companies,2 these Chinese firms have grown into global companies, raising huge amounts of money by listing on the Hong Kong, New York, and London stock markets, and aggressively entering the global markets. Thus FDI both inward and outward has remarkably strengthened the competitive global position of Chinese industries, and led to an unprecedented economic growth in China2.2 Foreign tradeFrom 1978 to 2012, China’s foreign trade increased amazingly by 187-fold. China has also been the world largest exporter and the second largest importer since 2009, while it was ranked in the twenty-ninth in world trade in 1978. China accounted for 11.2 percent and 9.8 percent of the world’s exports and imports respectively in 2012. In the transitional period to the economic opening to the outside world in the early 1980s, a number of Chinese political and academic leaders pointed out the benefits from foreign trade, particularly export, as follows. Foreign trade activities create demands in themselves. Export is regarded as an important source of foreign exchange, which enables China to import capital and intermediate goods essential to economic growth and to get easy access to the advanced technologies embodied in them. Having a wide range of spill-over and demonstration effects, foreign trade leads to productivity gain, technological progress and capital accumulation in Chinese industries at a developing stage. In fact, China has significantly benefited from foreign trade. With the opening-up to the outside world, a number of competitive foreign products entered the domestic market in China, while Chinese firms involved in export were faced with their competitors in the global market. Foreign trade exposed them to severe competition at home as well as abroad. Competitive pressure engaged Chinese firms in developing new products, innovating technology and upgrading industrial structure for survival. Imported capital and intermediate goods with advanced technologies also raised productivity and reduced production costs. Expanding production let the economies of scale work properly, and increasingly raised productivity in Chinese industries. With an increase in export production, China gained a sizable amount of foreign exchange, which enabled it to import more consumer as well as capital and intermediate goods. Needless to say, some Chinese firms were forced to exit the market as a result of losing against the competition. Resource reallocation and productivity have been remarkably improved through such tough competition. In addition, income growth accompanied by an expansion of production diversified Chinese consumers’ behavior to a great extent, and stimulated them to import a variety of foreign products. Foreign trade has accelerated economic growth in China by upgrading not only the production but also the consumption structure.

著者人数: 11名, 資料番号: SA1003723000

A cosmic dust detector for installation on a satellite is currently being developed using piezoelectric lead zirconate titanate (PZT), which can possess both functions of the collector and the transducer. The characteristics of the PZT detector have been studied by bombarding it with hypervelocity particles supplied by a Van de Graaff accelerator. The front surface of the detector used in this study was covered with a white paint to reduce any increase in the temperature due to the solar radiation. There was a linear relationship between the rise time of the signal produced by the detector and the particle's velocities, which were above 10 km/s on impact. This implies that individual particle velocities on impact can be inferred through the empirical formula derived from the data obtained from the PZT detector.

Since the end of the Cold-War Regime in the beginning of nineties, the torrent of globalization forced each nation to make their system compatible with the global standard.Engineering education is not outside of this stream.Japan needs extra effort to cope with this demand, since our systems are out of global standard in many aspects.Two major problems we face, are the establishment of professional engineer qualification and the introduction of accreditation system of engineering education.Current movement for the establishment of Japan Accreditation Board for Engineering Education (JABEE) is explained.

The amount of the land transportation is limited due to the traffic congestion and environmental pollution in Japan.In order to solve this problem, the way of the transportation is to be sifted from trucks to sea way.To realize the change, high speed vessels with light and high efficient machinery are required. Especially for the main engine, it is required maximum power with minimum weight.To cope with this requirement, the authors developed ultra high power, high speed diesel engine having the bore 320 mm, which is the largest high speed engine in the world.Advanced technology including two-stage turbocharging and Miller systems in a field of large four-stroke diesel engine are adopted in order to achieve such ultra high power.Finally, more than two times as high power as the conventional engine with the same bore could be achieved. (bmep = 2.89 MPa, mean piston speed =12.0 m/s, 700 kW/cyl, 1000 rpm.)

The basic mission of universities has not changed since their birth in Europe in the 13th century. Universities have been serving as the centers, where people gather for exchanging and creating new knowledge. Despite this invariable mission of universities, education, especially engineering education, has undergone continuous reform. The present paper intends to crystallize the motivation of past educational reform in engineering education from the viewpoint that the reform reflected the needs of industries in each era. The examples are taken from Japanese experiences. In the same context, the changing industries toward the 21st century suggest us what reforms are needed in the engineering education of tomorrow.

As China receives increasing international attention as an emerging donor, there is also much criticism of its foreign aid. It has been said that China is pouring massive amounts of money into Africa and is even offering a helping hand to some of the continent’s dictators and rogue states in order to secure enough natural resources to maintain its high economic growth rates. Its involvement in Africa is supposedly also leading to a decline in local industries through the transfer of Chinese workers to implement diverse international cooperation projects that can inflict great damage on a recipient country’s environment. Moreover, the agencies and firms implementing China’s foreign aid seem to have made a concerted effort to realize the country’s national interests under the direction of the Chinese government. On occasion, therefore, China’s practice in developing countries is criticized as neocolonialism. 1

China’s foreign aid is rapidly gaining momentum. While the term ‘foreign aid’ does not correspond in China to the OECD’s notion of ODA (official development assistance), the two concepts share certain similar basic elements, as Chapter 3 in this book illustrates. Although China is usually labelled an ‘emerging donor’, it has a long history of aid-giving, as assistance to Vietnam and the Democratic People’s Republic of Korea was started in 1950. After a period of stagnation, China began to accelerate its foreign aid in the 1990s; it established the Export-Import (EXIM) Bank of China in 1994 and introduced concessional loans in 1995. Since then, China has rapidly expanded its activities in the developing world under its strategy of zouchuqu (going out).

The history of mechanical engineering education at the University of Tokyo is surveyed and the trend of evolution in the curricula and their requirement conditions is studied. The survey covers the past 106 years between 1886 and 1991, and ten representative curricula are selected from that period. Courses of each curriculum are classified into seven categories and listed for comparison. The history of curricula indicates that the traditional mechanical engineering curriculum, which features heavy concentration in applied mechanics education, took its present form half a century ago and continued until the mid 1980s. The shift from power-driven machines to information-driven ones required qualitative change in mechanical engineering education, and a new generation of curriculum with the combination of natural and artificial sciences appeared in recent years.

Thin-film formation on a rotating disk during the spin-coating process is analyzed. In the experiments for a solution of PMMA (polymethyl methacrylate) solute and chlorobenzene solvent, the final film thickness of dry film formed on silicon wafers for integrated circuits is measured with an ellipse thickness meter. Also, the transient film thickness during the entire film formation process on a rotating optical glass is measured using a laser displacement meter. A numerical calculation considering heat and mass transfer such as solvent evaporation is performed using a one-dimensional complete model proposed by the authors for each phase of liquid film and adjacent gas phase. Satisfactory agreement is obtained between these numerical and experimental results and the effect of various process parameters, e.g., spinning speed and initial film thickness, is clarified by this study.

Summary Objectives To determine the location of the parotid duct orifice in relation to the maxillary molars and its influence on oral clearance on the buccal surfaces of the maxillary molars. Methods A 2-mm hole was made at the centre of an adhesive therapeutic agent for aphthous stomatitis and the agent was placed on the mucosa so that the hole matched the parotid duct orifice. To locate the orifice, an impression of the buccal tooth surfaces and mucosa around the agent was taken with the teeth in centric occlusion. To evaluate the oral clearance rate, 12 subjects who displayed the parotid duct orifice within 1S.D. of the mean values obtained from the original 35 subjects were selected. 1% agar containing 1 mol/l potassium chloride was placed into three cylinders positioned horizontally, 6 mm apart, in an acrylic holder centred over the mean duct location. The diffusion chambers were taken from the mouth at selected time intervals and the gel transferred quantitatively to flasks containing 300 ml of 100 ppm NaCl, which was assayed for potassium by atomic absorption spectrophotometry. Half-times for clearance were calculated. Results The mean location of the parotid duct orifice was −0.4 mm (range −7.5 to +6.1 mm) mesial to the contact surface between the maxillary first and second molars (where negative values indicate mesial and positive values distal) and 7.2 mm (range +3.8 to +10.4 mm) above a line touching the buccal cusps of the upper molars. The clearance half-time values were shortest for the central cylinder whether salivary flow was unstimulated or stimulated and when flow was unstimulated the clearance half-time was shorter for the mesial than the distal cylinder. Conclusion The degree of individual variation in the location of the parotid duct orifice is great and its exact location will markedly affect oral clearance at different positions on the buccal surfaces of the upper molars.

The temperature recorded immediately after hypervelocity collision of microparticles comprising iron and nickel with a silver-coated piezoelectric plate was analyzed using photomultipliers of different spectral response characteristics. The conversion rate between the velocity and temperature is estimated to be ∼900 K/km∕s in the velocity range of 10–40 km/s. This rate is greater than that reported earlier.

A cosmic dust detector for use onboard a satellite is currently being developed by using piezoelectric lead zirconate titanate (PZT). The characteristics of the PZT detector have been studied by bombarding it with hypervelocity iron (Fe) particles supplied by a Van de Graaff accelerator. One central electrode and four peripheral electrodes were placed on the front surface of the PZT detector to measure the impact positions of the incident Fe particles. It was demonstrated that the point of impact on the PZT detector could be identified by using information on the time at which the first peak of the output signal obtained from each electrode appeared.

自動車の電子化を例にとって, 機械工学の中で起こっている変化を摘出し, 従来の力学ベースの機械工学に加え, 論理・手法ベースの学問を加えた新機械工学のイメージを与えている。このような変化に対応するためのカリキュラムの変遷を概観し, 教育の成果を高めるには, 履修方法に工夫を要することが力説されている。

In-situ measurement of dust particles in space is important to study the origin or dust particles as well as space debris. Impact-ionization dust detector can supply mass and velocity information of impacting dust particles through the shape of charge signals of impact-generated plasma. Here we have tested plane-parallel type detectors with a target plate and an entrance grid. So far we tested three models with different target diameters: 5cm, 15cm, 30cm and one rectangular model with 20cm x 20cm aperture. Through calibration experiments using dust accelerators, we confirmed that the mass and velocity of impacted dust particles can be estimated from shapes of charge signals, as are previous impact-ionization type detectors. We confirmed that the charge signals do not depend largely on the position of the impact on the target.

In recent years, two-stroke slow speed diesel engines with long stroke, large bore and a small number of cylinders are on the increase, to get higher propulsion efficiency of the engine and the propeller and less maintenance of the engine.Diesel engines with a small number of cylinders, however, have some kinds of vibration problem. Torsional vibration problem is one of them. In case of five-cylinder engines, for instance, 1-node 5th-order torsional vibration is often dangerous for normal shafting design, so some countermeasure is necessary. In such cases, ‘the tuning disk with hydrodynamic damping’ is useful.Of course, to get the optimum tuning for each different shafting, computer aided design (C.A.D.) is very useful.Using Geislinger damper, optimum tuning can be obtained by choice of suitable elasticity and damping.

To take out mechanical power from high pressure oil, an impulse type oil turbine of a construction similar to the Terry steam turbine was developed on the basis of the fundamental experiment and the study of the performance of a test turbine. The turbine mainly consists of a nozzle, a turbine wheel with many deflection grooves and several fixed deflection boxes. Comparing with a positive-displacement type oil moter, the oil turbine has such features as feasibility of high rotational speed, low idling resistance, simple construction etc. As the fundamental experiment, a static test of two-dimensional deflectors was carried out and design data for a deflector with minimum losses were obtained. Based on the data obtained from the above, a test turbine was built, and its performance was measured at different rotational speeds and also at different jet velocities. From this study the limit of performance of an impulse type oil turbine was clarified, and the necessary data for designing an efficient oil turbine were obtained.

Two adjacent rows of blades, which constitute a tandem compressor cascade, interfere aerodynamically with each other, so that the deflection angle and losses are different from those of a system having no interference. In order to calculate the interference effect on cascade performance, a method must be found for calculating the change of flow field due to interference. This paper presents a theoretical method for determining the two-dimensional incompressible potential flow through an arbitrary tandem compressor cascade based on a singularity method. This theory is especially suitable for the case in which the relative position between the two blade rows varies, while the blade profiles and settings remain constant. Results of sample calculation are shown and compared with the corresponding experimental results.

The purpose of this study is to estimate the change of the intermaxillary distance of the intercuspation on the molar followed with the variation of the occlusal contacts and the occlusal force.Fifteen subjects with normal occlusion were organized into the following three groups:(1) The complete dentition group;(2) The double crown at the first molar group;(3) The first molar missing group.Using IP-checker and EMG activity, the variation of the molar intermaxillary distance on the occasion of changing the occlusal contact and the occlusal force were measured.The following results were obtained.1. The intermaxillary distance of the molar intercuspation was affected by the variation of the EMG activity (occlusal force).2. The change of the intermaxillary distance under the occlusal force was very different between the disappearance of the occlusal contacts as to the bridge included the last tooth and that of the first molar.3. For this reason, the bite taking of bridge must be investigated from the new point of view.

著者人数: 11名, 資料番号: SA1003722000