field was 10 V with a current 15 mA cm-2, and the polarity was changed at 2-s intervals. The interesting result was that the gel strip moved along the bar, alternately expanding and contracting as the field reversed. A study of salt and surfactant concentrations revealed optimum concentrations for maximum motility.

Professor Osada's explanation for the phenomenon is as follows. "When the voltage is turned on, positively charged surfactant molecules move by electrophoresis toward the cathode and form a complex with the negatively charged gel, preferentially on the side of the PAMPS strip facing the anode. This causes anisotropic contraction, bending the gel toward the anode. When the polarity of the field is changed, the surfac

tant molecules are released from the gel and electrophoretically travel toward the anode, while new surfactant molecules form a complex on the other side of the gel and cause a straightening." Professor Osada noted that the changes in the shape of the gel are due to its cross-linked nature, whereby molecular motions are communicated to the macroscopic structure. Thus this effect is different from shape-memory materials, where shape change is caused by a phase transition.

Professor Osada showed a video tape of the "gel-looper," which "walked" at a velocity of 25 cm min-1. All present were fascinated by the gentle, musclelike action that was mimicked.

Dr. H. Ichijo, Research Institute for Polymers and Textiles, Tsukuba, reported work on the thermally induced phase transitions in polymer gels. His work began with the observation that linear, atactic poly(vinyl plays a solubility-insolubility tranmethylether) (PMVE) in water dis

sition at 38°C. The incorporation of such a polymer into a gel produces a material that undergoes marked volume changes at the transition temperature. In addition to temperature, such gels are sensitive to salt concentration and acidity. Tanaka has shown that the ratio of swollen volume to contracted volume can be as high as 1000 [3].

In Dr. Ichijo's work, atactic PVME was synthesized at ambient temperature by cationic initiation. The polymer is dissolved in water below the temperature of insolubility and is crosslinked by gamma ray irradiation. The resultant gel swells (<38°) and shrinks (>38°) reversibly in water.

The process of swelling and shrinking is relatively slow for a monolithic piece of gel, as solvent molecules must traverse long distances by diffusion. To improve the

kinetics of the swelling process, Dr. Ichijo increased the surface area in a number of ways. In one approach, a polymer blend of PMMA with sodium alginate was prepared and spun into fibers that were crosslinked with gamma radiation. These gel fibers have a spongelike morphology that leads to rapid swelling and shrinking in response to temperature changes. In a typical experiment, fiber diameter changes from 400 μ (20°C) to 200 μ (40°C) in <1 s.

Dr. Ichijo expects applications for gels where an external stimulus causes changes in chemical properties, such as hydrophilicity and hydrophobicity, physical properties such as dimension, strength, and elasticity, and optical properties such as opacity and transparency. An illustration of potential applications is found in the modulation of activity of enzymes. In this case, amylo-1,6 glucosidase from A. niger and PVME are irradiated in aqueous solution to produce agel. The activity of the enzyme trapped in the gel drastically decreases near the phase transition point of PVME. Apparently the exclusion of solvent above the polymer collapse temperature prevents glucose from permeating through the membrane. Lowering the temperature rehydrates the gel and re-initiates enzymatic activity.

Other approaches to achieving rapid response from polymer gels included the work of Professor M. Aizawa of the Tokyo Institute of Technology and Dr. T. Sawai of the Asahi Chemical Industry, Tokyo. They achieved an aqueous dispersion of "microgel" particles of poly(comethyl methacrylate-acrylic acid) (MMA-AA) in the presence of poly(L-lysine) (PLL). At pH's above 10, the MMA-AA was dispersed, but at lower pH's, the PLL bridged the microgel particles and caused phase separation (flocculation). The reversible phase change occurred in a

advantage of cross-fertilization of 3. E.S. Matsuo and T. Tanaka, J. Chem. Phys. 89, 1695 (1988).

fields. Thus, Professor Takagi and

Kenneth J. Wynne, who received his Ph.D. degree from the University of Massachusetts in 1965, is Program Manager, Organic and Polymeric Materials at the Office of Naval Research, Arlington, VA 22217-5000. Dr. Wynne's research interests include electronically conducting polymers, preceramic polymers, and polymer surface design and characterization. He is a member of the Polymer and Polymer Materials, Science and Engineering Divisions of the American Chemical Society. He is also a member of the Editorial Advisory Boards of the Journal of Ap plied Polymer Science, the Journal of Inorganic and Organometallic Polymers, and Polymers for Advanced Technologies.

Victor Rehn

INTRODUCTION

China is the great sleeping giant of Asia, with nearly 1.2 billion people on a land mass slightly smaller than the United States, and great stores of undeveloped natural and human resources. In recent history, Chinese scientific progress suffered enormously from the ten-year rule of the "Gang of Four," who bestowed upon the people of China the infamous "Cultural Revolution."

During those dark days of the Cultural Revolution (1966 to 1976), universities and research institutes were either closed or converted into virtual factories. Many educated persons, especially artists, entertainers, and writers, were persecuted, imprisoned, or sent to work in agricultural collective farms or in approved industry. Those few who were permitted to remain in their research or educational institutions were directed to produce practical products for the people, a category that excluded advanced education. Metallurgy departments were directed to produce steel, for example, and electrical engineering departments

were directed to produce electrical or electronic devices and to train workers to work in factories.

The effects of the Cultural Revolution are still felt strongly among the scientists and engineers, as well as among artists, religious leaders, and scholars of China. In the physics departments of universities and research institutes, most current leaders are scientists trained (largely overseas) prior to 1966. They are supported by young scientists trained in the 1980s, but there is an absent generation. Midcareer Ph.D. level scientists, who should have been trained in the 1970s, are very scarce in China. In their place are scientists with less academic training, who work to fill the void.

In the early 1980s China began a program to upgrade the staff and scientific equipment of its research laboratories. They sent many students overseas for advanced training and Ph.D. degrees. They also authorized the purchase of major scientific apparatus from foreign sources (Europe, the United States, and Japan). In the major research institutes now, researchers are using some of the

finest scientific apparatus available in Europe or the United States in the early 1980s. Little newer scientific equipment apparatus from overseas is apparent, but the quality and variety of Chinese-built scientific equipment has improved noticeably over the six years since my last visit. However, that is not to suggest that China is approaching self-sufficiency in scientific equipment, but only that significant contributions to laboratory equipment is now available from Chinese sources.

RESEARCH IN CHINA: WHO DOES IT AND WHO PAYS FOR IT?

Research in China is highly diversified among universities, research institutes, and industrial institutions. Each of the major ministries of government operates a network of research institutes whose efforts support both the long-range and shortrange goals of the ministry. Chief among the ministries involved in research related to solid state physics are the Ministry of Education, the Chinese Academy of Sciences, the

Ministry of Machinery and Electronic Industry, and the Chinese Academy of Space Technology. In addition, both provincial and major city governments may operate or fund research institutes.

As with any large country, research funding in China is provided by several agencies of government. Most funding for university research comes from the Ministry of Education. The Chinese Academy of Sciences (variously referred to as CAS, CAST, or Academia Sinica) operates more than 100 research institutes throughout the country. Although the institutes tend to be small by American standards (several hundred persons), they are prestigious and generally are productive research institutes with broad-scale of research and development activities.

Over the past few years, funding of research institutes has changed from total to partial institutional support. There are both positive and negative implications in this change. On the one hand, the level of institutional support from CAS has decreased considerably, relative to the total operating costs. On the other hand, opportunities are offered to seek either focussed-program support or support from collaborating industries. Funding opportunities in focussed national research and development programs may be in basic research areas, such as the State Key Laboratory program, or in development/application areas where major national needs are identified, and researchers are invited to compete for involvement.

As a consequence, five-year-plan goals are being approached through a competitive process as opposed to assignment as part of the mission of certain research units, as it were in the past. Although institutional support is sufficient to pay, survival

costs are still distributed to research institutes by CAS, funds for research equipment and other operations must be sought by the institute leadership.

At the time of my visit, about 12 areas of science had been identified for special funding from the Chinese National Science Fund. One of these is the development of superlattices and microstructures. Other priority subjects will be announced in the future, perhaps 30 in all. Funding for these priority subjects will consume about 10% of the total Chinese National Science Fund, I was told.

In addition, a separate budget exists for development of national critical technologies. These budgets are organized by separate ministries outside the purview of CAS. Also, the Commission of Science and Technology has a high-technology fund for larger projects that involve expert groups.

Priority research laboratories are being established. About 70 national centers for priority research have already been established, and 70 centers have been planned. (Hefei National Synchrotron-Radiation Research Laboratory is one of these national centers for priority research.) Most of these laboratories are not freestanding, independent research institutes, but rather are laboratories within existing research institutes, such as the Laboratory for Superlattices and Microstructures of the Institute of Semiconductors.

HIGHER EDUCATION

Higher education in China is provided through a hierarchy of universities, research institutes, and other institutions. The Ministry of Education funds most of the national universities, including the prestigious

Peking and Tsinghua universities in Beijing and the Fudan University in Shanghai. The Academia Sinica (Chinese Academy of Sciences) is the main provider of research facilities outside the universities, but operates only one university, the University of Science and Technology of China (USTC) in Hefei, Anhui Province.

Through its more than 100 research institutes scattered in various parts of China, Academia Sinica offers a considerable resource for research and for advanced education and training in the sciences. Most, if not all, of the institutes of Academia Sinica have a dual role of research and education, offering B.S., M.S., and some Ph.D. programs for employee-students. Although not so prestigious as a degree from a national university, an advanced degree from many of the Academia Sinica institutes involves working with advisors who are well-trained Ph.D. scientists of international fame.

For example, the Institute of Semiconductors in Beijing has an active education program. The Institute awards doctor degrees both in natural science and in engineering. Since 1978, the Institute has been taking in an increasing number of graduate students. Up to 1992, 42 master degrees and 5 doctor degrees have been awarded. At the present, 78 graduate students are at the Institute of Semiconductors, and 15 students are doing postgraduate studies at universities abroad.

All the national universities and research institutes are small by U.S. standards. The largest national universities have less than 15,000 students, and the majority of these are undergraduates. Typical research institutes of Academia Sinica have from a few dozens to a few hundred employee-students, mostly graduate