午后，突发跳水！4000亿龙头大跌8%，多只热门科技股跌超10%，发生了什么？

Market Overview - The market experienced a narrow fluctuation with the three major indices slightly declining, with the Shanghai Composite Index down 0.12%, the Shenzhen Component down 0.26%, and the ChiNext down 0.38% [1] - The total trading volume in the Shanghai and Shenzhen markets was 1.71 trillion yuan, a decrease of 115.3 billion yuan compared to the previous trading day [1] Technology Sector - The technology sector, including AI and semiconductors, faced a collective pullback, with notable declines in stocks such as Dingjie Zhizhi down 16%, Jinxiandai down over 12%, and Wanxing Technology down over 11% [3] - Semiconductor leader SMIC saw its A-shares drop over 4% and H-shares fall over 8% [5] - SMIC reported Q2 sales revenue of $2.209 billion, a year-on-year increase of 16.2% but a quarter-on-quarter decrease of 1.7%, with a gross margin of 20.4%, down 2.1 percentage points from the previous quarter [7] Water Power Sector - The water power concept rebounded, with Shanhe Intelligent hitting the daily limit, achieving 9 consecutive trading days of gains, and a single-day trading volume of 4.6 billion yuan [10] - The China Construction Machinery Industry Association reported that 17,138 excavators were sold in July 2025, a year-on-year increase of 25.2% [13] Brain-Computer Interface Sector - The brain-computer interface concept strengthened, with Sainuo Medical achieving a 20% limit up for two consecutive days [15] - Recent policies from the Ministry of Industry and Information Technology and other departments aim to promote innovation in the brain-computer interface industry, targeting breakthroughs in key technologies by 2027 [18] - Sainuo Medical's product received FDA breakthrough device designation, marking a significant milestone for domestic neuro-interventional devices [19]