We Live in Nanjing

The author's writing is really good. I made a picture with PS on a whim after reading it for the second time today. It's very rough, just for fun

Let me update the progress of Ban Xia Ge, we should be able to meet during the May Day holiday. Powered by love, I spent hundreds of dollars on illustrations, my heart is bleeding.

Some amateur radio slang that may be useful 1: CQCQCQ (means you want to talk, a broad call) 2: Insert (also means you want to talk) 3: Please speak (you, or multiple parties agree to talk) 4:59+ (means the signal is strong) 8:73 (Sending good wishes, often used for goodbye, etc.) 9:57 (indicating good signal) 10: Cannot afford the meter (indicating a certain difficulty in copying) 11: Full meter (the signal is in the best condition) 12: Restoration (referring to the other party's voice, no echo or unclear situation) 13: Coverage (Generally refers to the phenomenon that the car station covers the hand station more) 14: Eyeball (meaning to meet) 15: Copying (meaning you have received the other party's signal) 16: Noise (meaning the other party's speech is unclear, the signal transmission is unstable or there is equipment communication sound) 17: Listening (meaning to only listen but not talk) 18: Equipment (Referring to the station, or handheld station and a complete set of communication equipment) 19: Point (the position of you or the other party) 20: Lane 2, Lane 3 (Refers to several channels of fixed frequencies in the fleet, such as 420.100 Is 1 channel, 420.150 Is 2 channels) 21: Miaozi (car-mounted or handheld small antenna) 22: Bangzi (stick) (medium and large fixed antenna) 23:88 (more intimate kiss goodbye) 24: Listen (only listen and don't talk)

First of all, a common sense science. The threshold for radio is very low. You don't need to learn the principles to become a HAM. You only need to memorize the question bank and take the exam held by the local non-committee to obtain the operation certificate. Then take the radio station you bought to inspect the machine and apply for a license. After that, you can legally communicate. Elementary school students can use the school's group station to play shortwave. This is the first time I have seen a novel with amateur radio as the main theme. It is really good. Now fewer and fewer people play it. I am born in the 1990s. When I was a child, radios were still used at home and in school. After the popularity of smart phones, you can plug in a headset into your mobile phone and use it as a radio. But now radio has basically disappeared in daily life, and mobile phones have also lost their radio function and changed it to Internet radio. There are more frequencies that can be listened to, but they are gone when the Internet is disconnected. Listening to the radio has gradually become a niche, let alone amateur radio. At least most people born after 2000 still know what radio is, but not many know what radio is. Mobile phones are indeed convenient, but when there is a sudden disaster or entering a weak signal area, only radio can set up a communication network. The most impressive thing was the amateur radio rescue in the 2008 Wenchuan earthquake. Because there were many earthquakes in Sichuan, an emergency communication network was established before the earthquake. After the earthquake, a command and dispatch system was quickly set up. However, the signal was interrupted. Hanwang to Mianzhu relied entirely on amateur radio as communication guarantee, and Beichuan to Tangjiashan only relied on an amateur relay as a communication bridge. There was no other way to establish contact with the outside world except radio. HAM directly shouldered the communication task. At that time, some rescue forces focused on disaster relief supplies but neglected communications. In some areas, HAMs were required to carry radios on their backs to accompany the troops as they moved forward to provide communications support. A 7.1-Magnitude earthquake in Yushu, Qinghai, a huge mudslide in Zhouqu, Gansu, a 7.0-Magnitude earthquake in Ya'an... Amateur radios are always present before sudden natural disasters. Not long ago, heavy rains in Zhengzhou caused widespread power and communication outages. The Zhengzhou Radio Administration Bureau temporarily coordinated four radio frequencies for emergency use, and advocated the active use of amateur radio to assist the city's emergency rescue departments and social rescue organizations in emergency rescue and disaster relief. Amateur radio A certificate can use the UV segment, mainly hand-held radios and mobile radios. Hand-held radios only cost 200 to 300 yuan to get started. Quansheng tg-uv2, Baofeng 5r, etc. Are classic radio stations, and second-hand radios are cheaper. However, more and more people are playing digital nowadays, and there are fewer people on analog frequencies. B certificate can play shortwave, you can use direct voice or CW (Morse code tick tock). Shortwave stations are slightly more expensive, there are various types, and antennas need to be set up - usually on the roof. If it is not convenient to set up antennas on high floors, using a fishing rod antenna sticking out of the window will work. For outdoor communications, there are those kind of rod antennas, which are very portable. Relevant policies, regulations, question banks, etc. Can be queried on the CRAC (Amateur Radio Branch of China Radio Association) website, registration and examination information can be viewed on the local RRC website or WeChat official account, and you can join the local Amateur Radio QQ group for communication and understanding. The use of radio stations should be legal to set up station communications. This is BG2DFO, you are welcome to join.

Some new readers think the update is very slow. To clarify, old readers also think the update is very slow 🙂

Electric propulsion has the characteristics of high specific impulse, long life and highly autonomous cruise. The detector uses electric propulsion to perform orbital maneuvering tasks during the cruise phase, which will significantly reduce the propellant weight and increase the load-to-weight ratio. In October 1998, the US "Deep Space 1" (DS-1) spacecraft was successfully launched; in May 2003, the Japanese "Hayabusa" probe was successfully launched; in September 2007, the US "Dawn" probe was successfully launched; at the end of 2014, the Japanese "Hayabusa-2" probe was successfully launched. The above detectors are all equipped with electric propulsion systems and use them for main propulsion. The system performance is excellent. This article investigates the electric propulsion system solutions for foreign detectors. In response to the mission requirements of this slow delivery operation, based on the existing electric thruster technology, 5 electric propulsion system solutions are proposed, and multi-dimensional comparisons are made to design and key technologies for the optimal solution. 1 Introduction to foreign detector electric propulsion systems 1.1 The American "Deep Space 1" ion electric propulsion system [1-3] In October 1998, the American "Deep Space 1" spacecraft was launched. Its goal was to conduct close detection of the 1992KD asteroid and to detect comets 107PBorreiiy and 19PWilson-Harrington. The main mission of the ion electric propulsion system is to complete the main propulsion of the spacecraft during the cruise phase, and at the same time undertake the pitch and yaw control tasks during part of the period. The ion electric propulsion system increases the total speed of the spacecraft to 4.5 Km/s, and the cumulative working time of the ion thruster exceeds 16 246 h. The system block diagram is shown in Figure 1. Figure 1 Block diagram of DS-1 ion electric propulsion systemFig. 1 Ion electric propulsion system of SD-1 DS-1 ion electric propulsion system consists of a 30 cm ion thruster, a power processing unit (PPU), a xenon feeding subsystem (XFS) and a digital control & interface unit (Digital Control & Interface Units, DCIU). The ion thruster works with the support of xenon delivered by XFS and voltage and current conditions provided by PPU. XFS and PPU work under the control of DCIU. At the same time, DCIU receives and executes instructions from the satellite computer and transmits telemetry data of the ion electric propulsion system to the satellite data system. In order to match the output power of the solar panel under different solar distance conditions, the working power range of the ion thruster is designed to be 525-2300 W. It is Kaufuman type with a diameter of 30 cm. The design thrust range is 19-92 mN. The corresponding specific impulse range is 1950-3100 s. The design life of the full power 2.3 KW operating point is 8000 h. The gate component is a double gate structure made of molybdenum material, and the accelerating voltage is 1280 V. 1.2 Japan's Hayabusa ion electric propulsion system [4-5] In May 2003, Japan's Hayabusa probe was launched. Its mission is to detect the near-Earth asteroid 25143 Itokawa and obtain samples for return. The detector weight is 510 kg. The main task of the ion electric propulsion system is main propulsion during the cruise phase. In addition, in some phases, it also undertakes tasks such as orbit eccentricity correction, attitude control, and position maneuver maintenance. At the end of 2014, Japan's Hayabusa2 probe was launched to conduct rock sampling and return detection of the near-Earth asteroid 1999 JU3, which required a total velocity increment of about 2.2 Km/s generated by the ion electric propulsion system. The "Hayabusa" ion electric propulsion system consists of (as shown in Figure 2) 4 μ10 microwave discharge ion thrusters, 4 microwave power amplifiers, 3 power processing units (Ion Power Processing Unit, IPPU), a propellant supply subsystem, a thrust vector pointing mechanism and an ion thruster control unit. The dry weight of the system is 59 kg, the xenon carrying capacity is 66 kg, the cumulative working time of the four ion thrusters is about 40,000 hours, and the cumulative working time of the most used thruster reaches 15,000 hours. Four ion thrusters are installed in an array on the same thrust pointing mechanism. Three IPPUs switch power to the four thrusters through relays. Up to three thrusters can work at a time. Fig. 2 Installation of thruster on the spacecraft 1.3 American "Dawn" ion electric propulsion system [6] In September 2007, the American "Dawn" probe was launched. Its scientific goals are to understand the conditions and processes when the solar system began to form, and to measure the mass and shape of Vesta and Ceres. As the main propulsion system of "Dawn", the ion propulsion system provides the speed increment after launch to meet the mission requirements of various stages such as orbit transfer and capture. The "Dawn" flight system structure is shown in Figure 3, and the functional module of the ion propulsion system is shown in Figure 4. Figure 3 "Dawn" flight systemFig. 3 Dawn spacecraft Fig. 4 Function module diagram of "Dawn" ion propulsion systemFig. 4 Funciton module of Dawn Ion propulsion system The initial dry weight of "Dawn" is 1 215 kg, and the ion propulsion provides a speed increment ΔV of nearly 11 km/s. The xenon tank is loaded with 450 kg of xenon propellant. The operating time of the "Dawn" ion propulsion system exceeds 55,000 hours (6 years), which is three times the longest powered flight of other spacecrafts. The ion propulsion system can provide speed increments of more than 10 km/s. During the mission cycle, the cumulative operating time of the xenon ion propulsion system is nearly 6 years. In addition, high reliability requires the ion propulsion system of Dawn to have a single-point failure redundant safety design. 1.4 ESA Mars Sampling Plan Orbital Return Vehicle Ion Electric Propulsion System ESA and NASA plan to carry out a Mars sample return mission around 2030. The orbital return vehicle responsible for Europe is scheduled to be launched in 2027. Its scientific goal is to return Mars samples to provide support for the search for signs of life, geological composition and evolution, climate change, and interaction between the atmosphere and the ground. As the main propulsion of the main body of the orbit-return vehicle, the ion propulsion system provides Mars orbit maintenance, Mars sample capture and fire-to-ground transfer speed increments to meet the mission requirements of various stages such as orbit transfer and capture. The block diagram of the ion propulsion system of the orbit-return vehicle is shown in Figure 5. The ion electric propulsion part uses four RIT-2X ion thrusters. The working strategy is to ignite three units at a time. The four units take turns to serve as cold backup to balance the remaining life. The four units can also work at the same time to increase thrust and reduce losses. Fig. 5 Funciton module of ERO Ion propulsion system 1.5 Summary By analyzing the composition of the electric propulsion system of foreign detectors, the following conclusions can be drawn: 1) The detector uses an ion electric propulsion system not only for attitude control, etc., But also for main propulsion. 2) In the design of electric propulsion systems, redundant design is very important. For example, the "Dawn" propulsion system has redundant backup functions in the configuration of key system components such as PPU, DCIU, and ion thrusters [6]. 3) During cruising flight, the electric propulsion system generally uses continuous propulsion and works for hundreds or even thousands of hours at a time. 2 Mission requirements The main task of the electric propulsion system is to provide the necessary thrust for the transfer section of the "Meteor" probe from the Earth to Mars and to provide the necessary braking force for the Mars return and Earth rendezvous. According to the planning and orbit design optimization of this slow delivery mission, the mission requirements of the electric propulsion system include the following points: 1) Speed ​​incremental requirement: 12km/s. 2) Multi-point working mode: In order to match the output power of the solar panel under different solar distance conditions, the power of the electric propulsion system must be able to be adjusted at multiple points within the range of 0.5~5 KW. 3) Continuous and pulse working modes: According to the task analysis, in addition to the pulse working mode of scheduled power on and off, the electric propulsion system also needs to have the ability to work continuously for a long time. 4) Vector adjustment: The thruster needs to be equipped with a vector adjustment device to meet the needs of vector adjustment during the mission. 3 Electric propulsion system scheme design Based on the development status of domestic electric propulsion, there are mainly ion propulsion, Hall propulsion and arc propulsion to choose from. Five electric propulsion products that have existing domestic technology foundations include 5 kW ion, 5 kW Hall, 1.6 KW ion, 1.5 KW Hall and 2 kW arc can be considered. Considering that the specific impulse of the arc thruster is only 600 s, compared with Hall and ions, the specific impulse is too low, so ions and Hall are mainly used for comparison. The main indicator parameters and current situation are shown in Table 1. Table 1 Main parameters of the thruster With the initial dry weight of the mission as 1 200 kg and the speed increment ΔV requirement of 12 km/s as input parameters, there are five main design options for the electric propulsion system: Option 1: Configure two 5 kW ion thrusters with a specific impulse of 2 580~3 900 s and a thrust of 20~180 mN. Option 2: Configure three 5 kW ion thrusters with a specific impulse of 2 580~3 900 s and a thrust of 20~180 mN. Option 3: Configure two 5 kW Hall thrusters, with a specific impulse of 2 300~2 400 s and a thrust of 134~237 mN. Option 4: Configure four 1.6 KW ion thrusters with a specific impulse of 3 000~3 500 s and a thrust of 40~60 mN. Option 5: Configure four 1.5 KW ion thrusters with a specific impulse of 1 800 s and a thrust of 80 mN. The comparison results of the above five solutions are summarized in Table 2. Table 2 Comprehensive comparison of different schemes Through the comparative analysis in Table 2, the ion electric propulsion system requires the least propellant due to its high specific impulse, and consumes more than 100 kg less propellant than the Hall of the same power; in addition, the 5 kW LIPS300 ion electric propulsion system has a propellant consumption of 1.6 The kW LIPS200 ion electric propulsion has more advantages in terms of propellant consumption, cumulative working life, and system dry weight. At present, the design life of the LIPS300 ion thruster has reached 21,000 hours, and the life test is in progress. It has completed more than 1,800 hours and is expected to complete the life verification before 2021. Therefore, the system configuration with two LIPS300s can realize a complete cold backup design of the thruster, which can ensure the long-life reliability of the system. And the same propulsion scheme as the asteroid exploration mission is used, and existing electrical experimental samples can be directly used for assembly. In summary, the electric propulsion scheme is a 5 kW electric propulsion system based on two LIPS-300 ion thrusters.

Nanjing is awesome, 90 quickly added more to celebrate.

BV1QZ4y1C72P Come, come, please have a threesome🙏

Tianrui said that Fu was really a person disguised as a lover of he. Every hope in Mars will crash. The death of Ophiopogon japonicus is a fact, the old cat's shattered bones are a fact, and the destruction of the earth is also a fact. In the end, the deus ex machina aliens saved the earth, saved Ophiopogon japonicus and saved the old cat. Is that really true or is it just a brain in a vat? Nanjing is a complete tragedy. The distance between poplar and pinellia exceeds 400 of Mars. Kilometers, there is no aircraft, No. 47, Or a space station between them. Some only have an identical machine, and 20 years have passed in the history of human destruction. The last girl has not ushered in redemption. All speculations have been torn apart by the author. Some are just girls rushing towards countless swordsmen. No one knows, but everyone knows that this girl will only die. All in all, Tian Fu, you are on the same level as Jiangnan in my heart.

In the Life Plaza in February 2026, both buildings were still alive and no red balls were found. There are not only two non-combustibles left in Nantuli opposite The community next to Block B of Xintiandi is indeed convenient for hiding Time has brought some changes. The Chongqing Xiaomian Wonton Shop has changed one after another, and Yumixiang has also become a good place to visit. Pin Da San is still strong and deserves to be a landmark The density of cellars here is really high, and there are life-saving passages🆘 It should have climbed out from under one of them This is really not a treasure found. Brother Yan hid it really well🤭 I didn't see the rooster (suzaku), but I saw a dragon (maybe it was a dragon) Cong Cheng! 🫡, You can enter the community, but I'm too embarrassed to go upstairs to take a look You won't be able to meet the people you want to see I didn't go to the high school affiliated to China Southern Airlines, and passed by China Southern Airlines where I failed to pass the exam. Plum Blossom Villa is indeed very safe, and it's just around the corner. If foreign forces can come over, there's nothing to say Yixian Bridge is really easy to walk through, what route is arranged? This is Zitai Office Building... I don't know if it is the Tailou Office Building or this..., I didn't dare to take more pictures, so I slipped away I blocked the Zifeng Building and Wangxia ran to death. I didn't win Mochou Lake, Mochou, Mochou, all sorrow I have to say that Nanjing is quite suitable for cycling. There are shared bicycles all over the streets. The terrain is flat, occasionally a little uphill, and the slope is not large. I don't know if it's because the Chinese New Year is coming, and there are not many cars and people on the road. Riding a bicycle is leisurely and comfortable, but you have to be careful not to compete with your head and tree trunks to see who is harder I also lived in Nanjing.