In the spring of 1945, a decisive campaign in the mountainous terrain of West Hunan in central China became the final major battlefield victory that compelled Imperial Japan's surrender, ending its 14-year aggression against China and marking a pivotal turning point in the World Anti-Fascist War.
Veteran Zhou Guangyuan, now 98 years old, clearly recalls August 21, 1945, when China received Japan's surrender document, ending the 14-year Chinese People's War of Resistance Against Japanese Aggression. It was the first instrument of surrender signed by Japan during World War II.
The turning point began months earlier. On April 9, 1945, Japan launched an offensive with 100,000 troops into West Hunan, aiming to capture the Zhijiang Airport used by Allied forces and control key railroads in an attempt to threaten Chongqing -- China's wartime capital.
China, however, was well-prepared. Under General He Yingqin's command, a 200,000-strong defensive force had been assembled and stood ready to engage the invaders in what was later known as the Battle of West Hunan.
From the skies, the Japanese advance was relentlessly pounded by Sino-American air sorties based at Zhijiang. This air power was a key deterrent against Japanese expansion after the attack on the Pearl Harbor in December 1941.
Amid the crossfire in West Hunan, Zhou had one critical mission.
"Our combat mission was to protect a three-member U.S. military [advisory] team stationed in the Xuefeng Mountains. The American team directed precision Allied airstrikes against Japanese forces using field radios and signal panels," he said.
"At that time, American and Chinese air forces fought side by side. During the campaign, they jointly conducted 3,100 sorties, dealing a devastating blow to the Japanese invaders," said Wu Jianhong, curator of Zhijiang Flying Tigers Museum.
On the ground, Chinese troops offered fierce resistance. One of the most intense battles took place in Jiangkou Town. On May 1, 1945, Japan's 133rd Division faced a strong Chinese counterattack.
"The fiercest fighting occurred on May 5. That night, the Japanese launched eight assaults but failed. By dawn on May 8, the Japanese forces had fully retreated," said Xiao Xiangsheng, witness of the Battle of Jiangkou Town.
This battle resulted in the elimination of over 3,500 Japanese soldiers, Xiao added.
From May 8 onward, Chinese forces launched a full counteroffensive. By June 7, they achieved decisive victory in the Battle of West Hunan.
"This battle along the Xuefeng Mountains successfully defended the Zhijiang Airport, safeguarded Chongqing, inflicted heavy losses on the Japanese invaders and ultimately accelerated Japan's unconditional surrender," said Liu Baisheng, author of The Xuefeng Assault.
On August 15, 1945, Japan announced its unconditional surrender. Six days later, envoy Takeo Imai flew to Zhijiang, where he submitted military maps and signed the terms of surrender. The formal surrender ceremony of the Japanese forces in the China Theater was held on September 9, 1945, in Nanjing City of east China's Jiangsu Province.
During 14 years of relentless anti-fascist struggle, China accounted for more than 1.5 million Japanese soldiers killed, wounded, or captured --representing 70 percent of Japan's total military casualties in the World War II. After Japan's defeat, more than 1.28 million Japanese troops surrendered in China.
China's military and civilians suffered more than 35 million casualties in their struggle against the bulk of Japanese militarist forces, making China a major contributor to the victory of the World Anti-Fascist War.
Battle of West Hunan: China's last major offensive forcing Japan's surrender
Major breakthroughs by Chinese scientists have laid the foundation for a future where space-based solar power stations are capable of wirelessly transmitting energy to Earth and spacecraft, though significant engineering problems remain.
A research team from Xidian University in northwest China's Shaanxi Province has made significant progress on the Sun Chasing project, or "Zhuri" in Chinese. The team has developed a ground-based test system for wireless power transmission that can charge multiple moving targets at the same time.
In recent tests, the system achieved a wireless power transmission efficiency of 20.8 percent from direct current to direct current over a distance of 100 meters. It delivered 1,180 watts of power. The team has also built a wireless charging system for drones. In a test, a drone flying at 30 kilometers per hour was able to receive 143 watts of stable power from 30 meters away.
A space solar power station works exactly as its name suggests: a huge array of solar panels placed in orbit. It would collect sunlight in space, where the sun always shines, and then convert that energy into microwaves or lasers to beam down to Earth or directly to satellites and spacecraft. This could address two significant issues: supplying uninterrupted power for space missions and alleviating energy shortages on the ground.
"The construction of space solar power stations could become a major undertaking in the future. One potential benefit is access to a virtually unlimited power supply. Because energy can be collected continuously in space 24 hours a day, electricity could be supplied on an uninterrupted basis," said Fan Guanheng, an associate professor at the School of Mechano-Electronic Engineering at Xidian University.
"Secondly, it could reduce our dependence on fossil fuels, thereby lowering carbon emissions and helping protect the environment. Thirdly, it could support the development of charging infrastructure in space and enable wireless microwave charging for spacecraft, changing the way power is supplied to space vehicles," the professor added.
In 2018, the research team launched the first phase of the Sun Chasing project to build a ground test system. By June 2022, they had completed the world's first full-link, full-system ground validation system for a space solar power station. Now, the team has moved to phase two. The goal now is to solve the challenges of generating high power in space and transmitting it efficiently over long distances.
According to Duan Baoyan, an expert at Xidian University and an academician of the Chinese Academy of Engineering, recent breakthroughs include improving the efficiency of solar energy collection and conversion, increasing the precision of microwave beam control to reduce energy loss, and making the transmitting and receiving antennas smaller and lighter, which is critical for space application.
The team has also solved the problem of how to power multiple moving targets at once using a single transmitter. This means that in the future, one space power station could potentially supply electricity to several satellites or ground vehicles at the same time, Duan said.
Despite the advances in ground-based validation, a series of technical challenges must still be overcome before the technology can be deployed in space.
"The first issue that needs to be addressed is the adaptability of components to the space environment, as conditions in space are completely different from those on Earth, including radiation exposure and extreme temperatures. Another challenge involves the deployment and retraction design of transmitting and receiving antennas. We also need to develop thermal management systems to cope with extreme temperatures and temperature fluctuations in space. These are all areas where further breakthroughs are needed," said Qian Sihao, an associate professor at the School of Mechano-Electronic Engineering at Xidian University.
"We have now completed the development and validation of a ground-based test system, and our next step is to carry out in-orbit wireless microwave power transmission," Fan said.
With ground validation complete, the team now turns its attention to overcoming the harsh realities of space, aiming to demonstrate in-orbit wireless power transmission and bring the vision of orbital solar energy closer to reality.
Space-to-earth solar power moves closer to reality although hurdles remain: scientists
