A growing demand for smart and flexible photovoltaic power conversion and pulsed-power systems is leading to rapid development and commercialization of medium voltage 6.5 - 24 kV, wide-bang gap rectifiers and switches. Conventional silicon bipolar switches are limited to roughly 8 kV breakdown voltages and scaling up the voltage rating requires very thick wafers presenting significant manufacturing challenges. Very thick drift layers of silicon devices also translate into a very high minority carrier charge injected during forward conduction for an efficient conductivity modulation, hence leading to an extremely slow switching speed and poor efficiency. In this paper USCi presents the development of 6.5 kV 4H-SiC gate-turn-off thyristors (GTOs) with multiple floating guard-ring edge termination, and describes their application in an AC-link grid-tied solar inverter system.

There is a growing demand for medium voltage, 6.5-24 kV, switches capable of operating at more than 15 kHz frequencies. The range of potential applications includes grid-tied solar inverters and pulsed-power applications, where the conventional silicon thyristor technology is plagued with slow switching speeds at medium blocking voltage requirements. In this paper we present the design and characterization of 7.5 kV 4H-SiC Gate-Turn-Off thyristors (GTO's) with multiple floating guard-ring edge termination, and present GTO switching performance at 10 kHz in an AC-link™ [1] inverter.

The widespread adoption of energy storage deployment requires the cost for the power conversion stages to be significantly reduced. The high cost of inversion is driven largely by the performance limitations of Si-IGBTs and SiIGCTs, especially when a higher DC-link voltage (>1 kV) is desired to facilitate the reduction of the balance-of-system. SiC unipolar devices, however, offer great promise for increasing the DC link voltage, while maintaining high system efficiency without increasing system complexity. Such a switch platform could enable small, lightweight, transformerless topologies for industrial medium voltage grid applications operating at 3.3 or 4.16 kV AC. This report discusses the state-of-the-art 1.2kV SiC JFETs as a proven technology platform, and demonstrates the benefits of the JFET through operational comparisons with SiC-MOSFETs and Si-IGBTs. In addition, SiC JFET device reliability is demonstrated up to 200°C and the impact of a 6.5 kV JFET platform on power conversion systems is discussed.

The high penetration of utility-interconnected Photovoltaic (PV) systems requires nontraditional and seemingly noncompliant modes of operation as a method to accommodate the high level of distributed generation at the distribution level. The normal operation of utility-interconnected PV systems is governed by IEEE 1547 Standard for Interconnecting Distributed Resources with Electric Power Systems and provides relevant requirements for performance, modes of operation, safety, and maintenance considerations. A recommended practice that provides flexibility of the existing interconnection standard by expanding the implementation requirements for utility interconnection is currently being addressed in IEEE 1547.8. The proposed recommended practice establishes methods and procedures for the expanded use of the governing utility-interconnected standard and is intended to address the increasing implementation of a varying resource. This recommended practice is designed for the implementation of advanced smart-grid functionality and allows the continued operation of Distributed Energy Resources (DER) during abnormal voltage and frequency conditions. The distributed resource smart-grid functionality is described in IEC61850-7-420, Advanced Functions for DER Inverters Modeled in IEC 61850-90-7. This report describes the implementation of advanced functionality and successful criteria to assess proper operations of the “smart inverter” under communication driven control.

painters. Modern Korean art and Korean modernism cannot be explained as a series of authentic responses to the country's industrialization and modernization process. If impressionism, post-impressionism, expressionism, cubism, and other artistic movements were all "imported" and "reproduced" at roughly the same time, if an artist could paint an impressionist landscape in the morning and a fauvist portrait or abstract composition in the evening, these still constitute authentic responses, just not the same responses to the same changes of modern life that we saw in the West. To this reviewer, these are probably the most central issues for the understanding ofmodern Korean art. In the Korean historical, social, and cultural context, all Western styles were avant-garde. Unfortunately, Kim's book does not address such important theoretical questions. Chapter 2 presents Kim's original research on the Korean participation at two world fairs, the World's Columbian Exposition in 1893 in Chicago, and the turn-of-the-century Exposition Universelles in Paris. While off-topic—modern Korean art is not discussed in this section—it is still an interesting read. The fourth chapter, about Jean-François Millet's reception in Korea (and also based on the author's original research), is likewise interesting, even though the stylistic comparison between Millet and Yi Yöngil's "Village Children" (1929) seems somewhat forced (see p. 100) and the Chosön Ubo review by Yi's contemporary An Sökchu is quoted somewhat out of context (it was not a stylistic comparison). The other four chapters that comprise part 1 cover very familiar themes from the South Korean art journalistic discourse over the past twenty years. These include the discussion of the vanguard New Woman/New Girl phenomenon that had come over from Japan and that has been extensively studied in the field of Korean literature; the promotion of local color painting and its relationship 122The Journal ofKorean Studies to colonialism, nationalism, and national identity; an account of Korean artists' activities in Japan during the 1930s; and a description ofmodern Korean sculpture and its only early proponent, the left-leaning political activist Kim Pokchin. To have such detailed summaries of these issues now available in English is a welcome scholarly contribution to the field. Part 2 of 20th Century Korean Art sums up South Korean postliberation art. Surprisingly it is shorter than the first part. It ends its coverage in 1997. In this section, Kim's focus is again primarily on painting. She provides an introductory chapter to this period, followed by a chapter on the Korean informel movement and abstract expressionism. This section discusses the Koreanization of modern art through various (mostly material) means (e.g., hanji, Korean-made paper), and symbolism. A chapter about painter Kim Whanki (Kim Hwan'gi) follows, and two further chapters deal with the art ofthe 1 970s to the 1 990s, one on monochrome art and minjung art—an unconventional idea to deal with both in the same chapter— and one on art trends of the 1990s. Minjung art, a truly decolonizing, and in many ways important, Korean art movement and style, is covered in just four-and-a-half pages. Discussion of the 1990s is also limited to a few pages. In summary, 20th Century Korean Art would have served readers better had the author paid greater attention to modern Korean art's inherent qualities as art. With few exceptions, there seems to be far more interest in the theme of "Koreanization" by nationalist historians and Western Koreanists than by artists themselves. Youngna Kim herself also writes more from the perspective of a nationalist or cultural historian than from that ofan art historian. Her descriptions and discussions of the artwork are far too short to allow the reader to form an alternative understanding or perspective from those of the author. Modern Korean Ink Painting by Chung Hyung-Min offers a condensed but fascinating and generally well-written text on the subject. I review the book here, together with Kim's work, because it touches on some of the basic institutional, structural, stylistic, aesthetic, and political issues of modern art production and reception in Korea. The term tongyanghwa—Eastern-style painting, sometimes translated as "Oriental painting" and now being called Han'gukhwa in the South (while the North uses Chosönhwa)—is a colonial-period term introduced by the Japanese. Even the term for art itself, misul, is actually a Japanese-derived neologism, only introduced to the Korean language in 1884. Throughout its history, modern Korean painting has been divided into tongyanghwa and söyanghwa (Western-style painting). The creation of such a binary East/West opposition immediately created privileges and hierarchy: Only oil painting was identified with the West, and the West was strongly associated with the modern. Brush-and-ink painting was thus continuously put on the defensive, having to prove its worth by rapidly modernizing. Chung Hyung-Min divides her book into three sections: (1) Dawn of the Modern Age: 1876-191Os; (2) The Modern Art Era in Korea: 1920s-1940s; and (3) Perpetuation of Nationalism: 1950s1980s. While I can think of many other

Secretory production of a single-chain antibody fragment (scFv) by recombinant Pichia pastoris using the methanol inducible AOX1 promoter is limited biochemically by retarded secretion, and economically by the high demand for pure oxygen. To address the problem, the adaptation phase with growth-limiting feeding of glycerol before the production phase was optimized. In a standard procedure with a short glycerol-feeding phase before induction, scFv accumulated in the supernatant only after 15 h. Conversely, scFv started to appear immediately in the medium upon methanol induction when the glycerol-feeding phase was extended to 18 h. Interestingly, despite a significantly lower cell density in the cultivation with extended glycerol feeding, the same amount of functional product of 300 mg/L was obtained about 30 h after the start of glycerol feeding with both methods. mRNA analysis revealed that the higher and faster production of the product was related to longer lasting induction of the scFv mRNA. Additional effects of a better adaptation of the secretion machinery may be suggested by higher expression of unfolded protein response-related genes KAR2 and PDI. A clear benefit of the longer glycerol-feeding phase was a 75% reduction of the consumption of both pure oxygen and methanol, and a significantly lower cell density, which would be beneficial for down-stream purification of the product.

Purpose: The purpose of this study was to evaluate the efficiency of the suprascapular nerve (SSN) block in pain reduction after arthroscopic subacromial decompression operations and its influence on patient satisfaction. Furthermore, we wanted to evaluate whether better perioperative pain management could positively influence postoperative shoulder function. Methods: In this prospective, randomized, double-blinded clinical trial, 3 groups of patients-each with 15 participants-were treated with SSN block (10 mL of 1% ropivacaine), placebo, or a subacromial infiltration of local anesthesia (20 mL of 1% ropivacaine). Preoperative and postoperative pain was evaluated with a visual analog scale. Functional outcome was measured by the Constant-Murley score, and patient satisfaction was measured anecdotally by interview 2 days, 2 weeks, and 6 weeks after surgery. Results: The SSN group reported significantly lower levels of postoperative pain, required significantly less analgesia, had better range of motion, and had higher levels of postoperative satisfaction in comparison to the subacromial infiltration group and placebo group. Conclusions: Patients treated with SSN blocks had less pain overall, which led to a decreased need for analgesics in comparison to the subacromial infiltration and placebo groups. Furthermore, patients in the SSN-blocked group achieved better postoperative ROM and were significantly more satisfied after surgery. Level of Evidence: Level I, prospective, randomized, double-blinded clinical trial.