Latest news with #NorthwesternPolytechnicalUniversity
Yahoo
25-05-2025
- Science
- Yahoo
China enables 375-mile long-range submarine messaging with acoustic breakthrough
Chinese researchers have achieved a major breakthrough in underwater communication, successfully transmitting acoustic data without errors across 375 miles in the ocean. The achievement, detailed in China's leading acoustics journal Acta Acustica, represents a major step toward making long-range undersea messaging a practical reality—a technology with far-reaching civilian and military implications. In 2010, a US Navy experiment demonstrated that underwater communication was possible across 342 miles, and whales are known to exchange low-frequency songs over distances exceeding 5,000 miles. The distance covered by China with its latest innovation is roughly equal to the stretch between Taipei and the US military base in Okinawa. Yet achieving zero-error transmission over such vast ranges has remained a major challenge. For some users—particularly the military—even slight data corruption is unacceptable for critical operations like activating dormant underwater drones or coordinating precision attacks, the South China Morning Post reported. Furthermore, underwater communication faces steep obstacles as seawater scatters sound into tangled echoes, Doppler shifts distort signals from moving sources, and ambient noise easily drowns out faint transmissions. Professor He Chengbing and his team at Northwestern Polytechnical University in Shaanxi, China developed a self-tuning system that can identify signal clusters in noisy underwater environments without requiring prior knowledge of seabed topography—a key advantage for naval applications. They also created an innovative algorithm that converts turbulent, time-varying channels into quasi-static 'acoustic snapshots' through mathematical transforms, enabling iterative error correction similar to sharpening a blurry photo with multiple exposures. However, the technology is still highly demanding in terms of computing power—processing a single transmission reportedly requires teraflop-scale performance, making it impractical for real-time use on small drones. Additionally, sudden changes in the communication channel caused by storms or abrupt maneuvers pose significant challenges to its reliability. In 2021, tests conducted at an undisclosed deep-sea location with an average depth of 3.4 miles achieved zero-bit-error acoustic transmissions over distances of about 202 miles and 370 miles. Using an eight-element hydrophone array attached to a buoy and coded QPSK signals, the system reached a transmission speed of 37.5 bits per second during the longer-range trial. These experiments confirmed the method's effectiveness in enabling error-free underwater acoustic communication across vast distances. According to the research paper in Acta Acustica, the 176-decibel sound source employed during the sea trials operated within the extremely low-frequency range, which is ideal for long-distance underwater communication due to its ability to travel farther with less attenuation. Recognized as one of China's 'Seven Sons of National Defence', Northwestern Polytechnical University has faced ongoing U.S. sanctions and cyberattacks due to its work in aerospace and naval research. Since establishing its underwater acoustics department in the 1950s, the university's graduates have contributed significantly to the development of China's most advanced warships and marine surveillance networks, according to its official website.
South China Morning Post
24-05-2025
- Science
- South China Morning Post
Taipei to Okinawa? China achieves 600km ‘error-free' underwater communication with sound
A team of Chinese scientists has passed a milestone in underwater communication, enabling error-free acoustic data transmission across 600km (375 miles) of ocean – roughly the distance between Taipei and the US military base in Okinawa. Advertisement The feat, detailed in a May study published in Acta Acustica, China's premier acoustic journal, marks significant progress that could pave the way for the real-life use of long-range undersea messaging, a field with profound civilian and military applications. While whales can exchange low-frequency songs over 8,000km, and a United States Navy experiment in 2010 showed communication across 550km was possible, maintaining zero-error transmission at such ranges has remained a challenge. For some users, including the military, even minor data corruption is unacceptable for critical tasks such as awakening dormant underwater drones or synchronising attack coordinates. The challenges are formidable. Seawater scatters sound into multipath echoes, Doppler shifts warp signals from moving platforms and ambient noise drowns faint whispers. At the distance of several hundred kilometres, a blast equivalent to a rocket launch can be reduced to a mosquito's hum. China's sea trials show error-free communication can be achieved at a distance of 600km. Credit: Northwestern Polytechnical University Led by He Chengbing, a professor at Northwestern Polytechnical University, the project team developed a self-tuning system that can map signal clusters in noisy environments without prior knowledge of seabed topography – an advantage critical for naval applications.
South China Morning Post
22-05-2025
- Science
- South China Morning Post
Chinese scientists prove US Air Force's Mach 16 engine concept ‘feasible'
A state-backed Chinese research team has achieved a breakthrough in developing a hypersonic engine powered by ordinary jet fuel, reigniting global debates over the viability of a technology proposed by US military nearly 70 years ago. In a peer-reviewed paper published in the Chinese-language Journal of Aerospace Power, a team of scientists announced a successful ground test of an oblique detonation engine (ODE) chamber burning RP-3 aviation kerosene. The experiment, simulating flight conditions at Mach 8 and and an altitude of 30km (18 miles), ignited and sustained stable detonation waves for over two seconds, which proponents said proved the concept's technical feasibility for military use. Researchers from the China Academy of Launch Vehicle Technology (CALT) – the nation's premier institute for aerospace propulsion – and Northwestern Polytechnical University jointly revealed the results on May 6. The ODE concept, first proposed by researchers with the University of Michigan under US Air Force-contract research in 1958, promises propulsion without moving parts by coupling shock waves with combustion. Nasa scientists theorised in 1978 that it could enable sustained hypersonic cruise from Mach 6 to 16 but the concept faced scepticism due to extreme technical hurdles.
Yahoo
02-04-2025
- Science
- Yahoo
A Curious Mutation Is Letting Earth's Deep-Sea Creatures Survive the Abyss
Despite everything stacked against them, a variety of life thrives at ocean depths with bone-crushing pressure, low-oxygen, no light, and immensely cold temperatures. A new study analyzes the evolutionary history of 11 deep-sea species from environments stretching from the central Indian Ocean and the western Pacific Ocean and found that all species contained the convergent evolution of the rtf1 gene, which improves transcription efficiency at higher pressures. Although other evolutionary changes also aid in these species' deep-sea survival, this universal adaptation shows that nature uses similar evolutionary solution when faced with overwhelming environmental challenges. Life isn't easy in the hadal zone. The deepest region of the world's oceans—stretching more than 6,000 meters (19,700 feet) below the surface—the zone is home to pressures up to 1,100 times stronger than Earth's atmosphere at sea level. Despite this extreme pressure—not to mention bone-chilling temperatures, low-oxygen levels, and absolute darkness—life thrives in these ultra-deep trenches, fractures, and vents, and a new study published in the journal Cell investigates how nature pulled off this incredible feat. In this new study, scientists from Chinese Academy of Sciences, Northwestern Polytechnical University, and BGI-Qingdao (a gene research institute) explored deep-sea fish habitats from the central Indian Ocean and the western Pacific, including the deepest point on the planet's surface, the Mariana Trench, using a variety of research vessels and piloted submersibles. From these habitats, the researchers reconstructed the evolutionary history of six major animal groups across 11 species, which included snailfish, tripodfish, cusk-eels, and lizardfish. While some species came from the hadal zone, this study also included specimens found all the way up to 1,218 meters (nearly 4,000 feet), which is still considered 'deep sea' by definition. This process identified two main 'pathways' for deep-sea fish evolution that largely supported a century-old hypothesis that attempted to answer how animals evolved to live in these seemingly inhospitable environments. The first pathway, which the researchers call the 'ancient survivors,' relates to species that have called these dark depths home for dozens or maybe even hundreds of millions of years. These organisms specifically navigated these pitch-dark waters before the end-Cretaceous mass extinction event some 66 million years ago. However, the 'new immigrants' are species that are recent arrivals (at least geologically speaking), having arrived in the hadal zone after the extinction of all land-based dinosaurs. However, across these different animal groups, species, and pathways, the researchers noticed that all specimens containing a highly conserved mutation impacted the rtf1 gene if the fish lived below 3,000 meters (nearly 10,000 feet). They found that this gene affects transcription efficiency specifically in high pressure environments and is likely the genetic mechanism for adapting to the crushing pressures found at these depths. This is an example of convergent evolution where separate species develop similar evolutionary changes despite not having a recent common ancestor. They also found that invertebrates were much more likely to survive in deeper ocean depths for two main reasons. 'First, as top predators, vertebrates require specific ecological conditions, including sufficient prey populations,' the authors write. 'Second, vertebrates may face significant challenges from the high pressure and darkness of the deep sea, possibly due to the sensitivity of their complex central nervous system.' The authors note that while they've found convergent evolutionary explanations for the deep-sea survival of these species, it's likely that a variety of other genetic changes additionally aid in these creatures' ability to survive the impossible. The team also detected traces of a anthropogenic pollutants, including polychlorinated biphenyls (PCBs), and believe future studies should analyze how this pollution could impact these incredible animals already surviving against all odds. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Asia Times
10-02-2025
- Science
- Asia Times
China's magnetic tech can detect US stealth subs: study
Could China's new magnetic wake detection technology mark the end of stealth submarine warfare? Recent Chinese research suggests it might. This month, South China Morning Post (SCMP) reported that researchers at Northwestern Polytechnical University (NPU) in Xian, China, have unveiled a novel detection method capable of identifying even the stealthiest submarines by tracking their magnetic wakes. The team, led by Associate Professor Wang Honglei, discovered that the magnetic fields generated by the wakes of submarines, such as the US Seawolf-class, can be detected using airborne magnetometers. This potentially groundbreaking technique exploits the magnetic interactions between seawater ions disturbed by the submarine's motion and the Earth's geomagnetic field. The study, published in the Journal of Harbin Engineering University in December last year, indicates that speed, depth and submarine dimensions influence the intensity of these magnetic signatures. Unlike traditional acoustic detection methods, magnetic wakes cannot be silenced and leave a persistent trace. The Chinese research comes after the USS Connecticut grounding in the South China Sea in 2021, which, among other things, highlighted the increasing challenges of stealth operations in contested waters. As China integrates magnetic tracking into its broader 'kill web' of detection technologies, underwater naval warfare may see a transformative shift. The rapid evolution of submarine detection technologies threatens submarines' traditional stealth and strategic utility, which, in turn, could necessitate innovations in submarine design, countermeasures and operational strategies to maintain their relevance in future conflicts. Shallow water environments like the Taiwan Strait reduce the effectiveness of traditional sonar systems, while technologies such as Magnetic Anomaly Detection (MAD) introduce new detection capabilities and limitations that complicate submarine tracking. Magnetic detection offers several advantages over sonar in shallow waters like the Taiwan Strait, which is no more than 150 meters deep. Bo Raskin of the Naval Submarine League states that shallow depths reduce low-frequency sonar effectiveness due to the absence of spherical sound spreading, leading to sound channeling, where energy is absorbed by the seabed and surface reflections. He adds that towed sonar arrays face challenges in passive detection because long wavelengths of low-frequency sound struggle to propagate in shallow water, while intense bottom reverberation and clutter from the muddy seabed limit the detection of small targets and range. However, Rajiv Sithiravel and other writers mention in an October 2020 article in the peer-reviewed IEEE Transactions on Aerospace and Electronic Systems journal that airborne MAD has a non-linear problem arising from the complex relationship between a submarine's magnetic signature and motion, complicating accurate tracking and estimation. Sithiravel and others say the left/right positional ambiguity prevents MAD from distinguishing whether a detected anomaly is to the left or right of the aircraft's flight path without additional maneuvers, such as curved flight paths. In addition, they note that MAD's short detection range makes it more suitable for short-range confirmation rather than long-range detection. Despite the threat posed by MAD and other sensor technologies, advances in stealth technology and tactics can keep submarines relevant in future conflicts. A January 2025 article by the Australian Naval Institute says submarines use anechoic tiles, vibration-damping materials, radar-absorbing materials and periodic degaussing to enhance stealth. The article also mentions that submariners employ techniques such as countering detection through noise manipulation and deploying uncrewed underwater vehicles (UUVs). However, Roger Bradbury and other writers mention in a March 2023 article for The Conversation that advancements in artificial intelligence (AI), sensor technology and underwater communications could potentially render submarines easily detectable and obsolete by the 2050s. Bradbury and others say these new technologies can identify slight variations in the ocean's physical, chemical, and biological markers and disruptions in the Earth's magnetic field caused by submarines, potentially compromising their stealth and significance in future conflicts. The US Navy must adapt its submarine design and operational strategies to counter the growing threat of multi-layered detection systems that combine advanced technologies. Combining airborne MAD with other technologies, such as magnetic wake detection, terahertz-based devices, airborne extremely low-frequency (ELF) radar, and light detection and ranging (LIDAR) satellites, can create a multi-layered detection grid to track US and allied submarines in near real-time. These advancements have the potential to impact US submarine design and operations significantly. Ryan Neuhard, in a March 2018 article for Georgetown Security Studies Review, says that the US Navy's submarine force faces the challenge of adapting to evolving detection technologies by pursuing several strategies. Neuhard suggests that upcoming submarine designs might prioritize minimizing sound, magnetic and wake disturbances to evade advanced detection systems, leveraging propulsion, hull design and magnetic cloaking innovations to enhance stealth capabilities. He adds that the US can improve the protection and effectiveness of its submarines against enemy threats by utilizing defensive measures like jammers and unmanned vehicles while also transitioning them to serve as command centers for autonomous systems. China's underwater surveillance system in the South China Sea challenges and threatens US submarine operations and has significant strategic implications for regional security and nuclear deterrence. At the strategic level, China's new submarine detection technologies can help secure the South China Sea as a protected bastion for its nuclear ballistic missile submarines (SSBN), which provide secure nuclear second-strike capability. In a December 2016 report for the National Maritime Foundation, Dolma Tsering says that China has built an 'Underwater Great Wall' (UGW), a comprehensive underwater sensor network in the South China Sea that combines sensors, sonar, unmanned underwater vehicles and surface ships to monitor both surface and underwater activities in real-time. Tsering mentions that China's UGW, modeled after the US Cold War-era SOSUS, improves China's submarine detection and tracking capabilities. She notes it directly challenges US operations and requires a reassessment of its undersea strategy, particularly in the strategically important Taiwan Strait. Further, in a March 2024 report, the South China Sea Strategic Situation Probing Initiative (SCSPI), a Chinese think tank, mentioned that in 2023 at least 11 US nuclear attack submarines (SSN) and two US SSBNs appeared in the South China Sea. While the report says they aim to 'exert deterrence,' the US SSNs may track China's SSBNs in the South China Sea. Such actions can be destabilizing at a strategic level, as China is highly likely to retaliate against threats targeting its nuclear arsenal. China's breakthrough in magnetic detection technology may well mark the beginning of the end for submarine stealth. As detection capabilities evolve, future conflicts could see submarines forced to shed their traditional invisibility cloak and adopt new roles, emphasizing long-range precision strikes, drone coordination and command-and-control functions. The question is not whether submarines will need to adapt—but rather, will they remain relevant in a new era of transparency beneath the waves?
