April 21, 1986

As President Corazon C. Aquino approaches the end of her second month in power, the euphoria of her victory has faded, and many Filipinos have begun to question her ability to exercise power and to make her Government work. Mrs. Aquino, who still appears in public dressed in yellow, as she did throughout her campaign, remains a popular and respected President who commands unmatched public support. But an odd mixture of aggressiveness and hesitancy in her early policy decisions has drawn comments from many here that she may not be moving to deal with the complex problems she faces in a coherent or decisive manner. Mrs. Aquino's personal style echoes her manner during the campaign, when she took an aggressive tone toward her opponent, but kept a demure demeanor that sometimes left her chanting supporters vaguely unsatisfied.

The number of nuclear explosions needed to perfect new types of nuclear arms is rising dramatically, according to Government scientists in Los Alamos, N.M. Senior officials of the Los Alamos National Laboratory said in interviews there that about six underground nuclear tests have usually been required in developing a new weapon. But the amount is rising, they said, as scientists try to create more complex nuclear arms. Perfecting one of these new designs could require 100 or 200 explosions, the officials estimated. ''It will take at least that many,'' said Dr. Robert W. Selden, head of theoretical and computational physics at Los Alamos. ''This is a very new thing. The physics processes we're looking at are far more complicated than anything we've looked at before.''

As Japan gradually eases the restrictions on its financial markets, Tokyo is posing an increasingly stiff challenge to Hong Kong's pre-eminence as a financial center. Until very recently, with Japanese markets tightly regulated by the financial authorities and key business areas closed to foreign financial institutions, bankers and brokers saw only limited opportunities in Tokyo. Hong Kong, on the other hand, with its laissez-faire Government, its anything-goes atmosphere and the considerable assets of its wealthy elite, proved the more enticing and rewarding Asian opportunity for major foreign banks and securities houses. But with the growth of Japan's pool of savings, its recent moves to deregulate its capital markets, the emerging importance of securities in international finance and uncertainty about Hong Kong's future under Chinese rule, Tokyo has grown considerably more attractive. Now it is well on its way to joining New York and London as a major financial center.

Congressional critics of lobbying by some former White House officials are considering new rules to limit lobbyists' activities. The Congressional scrutiny follows the swift success of former Reagan Administration officials as lobbyists who sometimes work for foreign governments. About 20 former governmental or campaign aides with close ties to President Reagan have earned large fees representing dozens of blue-chip domestic and foreign clients, including the Governments of Japan, South Korea, Saudi Arabia, Canada, the Dominican Republic, Singapore, Mexico, Grenada, the Netherlands Antilles and, until recently, the Marcos Government in the Philippines. Lobbying is a well-established practice in Washington, and what the former Administration aides are doing is legal so long as they follow certain rules. For example, they may neither lobby their former agencies for a year nor lobby on issues on which they worked ''personally and substantially'' as Federal employees.

Sid Fernandez sat quietly amid the postgame clubhouse crush, his hands folded neatly in his lap, his uniform still on, his answers brief and barely audible. His pitching yesterday afternoon was more eloquent and more revealing. Fernandez is a man of few words, but his work spoke loudly on a day on which the Mets completed a three-game sweep of the Philadelphia Phillies with an 8-0 shutout before 41,848 at Shea Stadium. Fernandez gave up just two hits in eight innings, although both of them could have easily been outs. Gary Redus led off the game with a single through the middle and then was caught stealing. Mike Schmidt started the fifth with a hit that skidded past Howard Johnson's glove at third base. Until he opened the eighth with consecutive walks, Fernandez had retired 20 of 23 batters.