今年美国签证形势整体开始发生转变，敏感专业的审查周期从以前的长达两个月缩短到2~3周，且因专业审查而遭遇申请失败的人数极少。但是，如果申请者所学的专业属于敏感专业，为了能按时到达学校，一定要提早向所在辖区的大使馆或者领事馆申请签证。

美国留学 敏感专业详细列表
The State Department maintains a Technical Alert List, also known as the sensitive major list, to guide their evaluation of visa submission.
Sorted by rate.
CRITICAL FIELDS LIST
A. CONVENTIONAL MUNITIONS: Technologies associated with:
-- Warheads and other large caliber projectiles
-- Reactive armor and warhead defeat systems
-- Fusing and arming systems.
-- Electronic countermeasures and systems
-- New or novel explosives and formulations
-- Automated explosive detection methods and equipment
B. NUCLEAR TECHNOLOGY: Technologies associated with
production and use of nuclear material for both peaceful and military applications. Included are technologies for:
-- Enrichment of fissile material
-- Reprocessing irradiated nuclear fuel to recover produced
plutonium
-- Production of heavy water for moderator material
-- Plutonium and tritium handling
Also, certain associated technologies related to nuclear physics and/or nuclear engineering. Includes materials,equipment or technology associated with:
-- Power reactors, breeder and production reactors
-- Fissile or special nuclear materials
-- Uranium enrichment, including gaseous diffusion,centrifuge, aerodynamic, chemical, Electromagnetic Isotopic Separation (EMIS), Laser Isotope Separation
(LIS)
-- Spent fuel reprocessing, plutonium, mixed oxide nuclear research
Inertial Confinement Fusion (ICF)
-- Magnetic confinement fusion
-- Laser fusion, high power lasers, plasma,
-- Nuclear fuel fabrication including Mixed Oxide (uranium-
plutonium) fuels (MOX)
-- Heavy water production
-- Tritium production and use
-- Hardening technology
C. ROCKET SYSTEMS (including ballistic missile systems,space launch vehicles and sounding rockets) and Unmanned Air Vehicles (UAV) (including cruise missiles, target drones, and reconnaissance drones): Technologies associated with rocket systems and UAV systems. The technology needed to develop a satellite launch vehicle is virtually identical to that needed to build a ballistic missile.
D. ROCKET SYSTEM AND UNMANNED AIR VEHICLE (UAV) SUBSYSTEMS:
Propulsion technologies include solid rocket motor stages,and liquid propellant engines. Other critical subsystems include re-entry vehicles, guidance sets, thrust vector controls and warhead safing, arming and fusing. Many of these technologies are dual-use. Technologies include:
-- Liquid and solid rocket propulsion systems
-- Missile propulsion and systems integration
-- Individual rocket stages or staging/separation mechanism
-- Aerospace thermal (such as superalloys) and high-performance structures
-- Propulsion systems test facilities