Fast solution to the free return orbit's reachable domain of the manned lunar mission by deep neural network

It is important to calculate the reachable domain(RD)of the manned lunar mission to evaluate whether a lunar landing site could be reached by the spacecraft. In this paper, the RD of free return orbits is quickly evaluated and calculated via the classification and regression neural networks. An efficient databasegeneration method is developed for obtaining eight types of free return orbits and then the RD is defined by the orbit’s inclination and right ascension of ascending node(RAAN) at the perilune. A classify neural network and a regression network are trained respectively. The former is built for classifying the type of the RD, and the latter is built for calculating the inclination and RAAN of the RD. The simulation results show that two neural networks are well trained. The classification model has an accuracy of more than 99% and the mean square error of the regression model is less than 0.01°on the test set. Moreover, a serial strategy is proposed to combine the two surrogate models and a recognition tool is built to evaluate whether a lunar site could be reached. The proposed deep learning method shows the superiority in computation efficiency compared with the traditional double two-body model.

China's First Manned Rendezvous and Docking Mission

At 18:37 on June 16,the Shenzhou 9 manned spaceship, with its crew of three, was launched into orbit on top of an upgraded LM-2F rocket from the Jiuquan Satellite Launch Center, commencing the manned rendezvous and docking mission with Tiangong 1. They spent over a week living and working on the Tiangong 1 space

Hydraulic model with roughness coefficient updating method based on Kalman filter for channel flood forecast

A real-time channel flood forecast model was developed to simulate channel flow in plain rivers based on the dynamic wave theory. Taking into consideration channel shape differences along the channel, a roughness updating technique was developed using the Kalman filter method to update Manning＇s roughness coefficient at each time step of the calculation processes. Channel shapes were simplified as rectangles, triangles, and parabolas, and the relationships between hydraulic radius and water depth were developed for plain rivers. Based on the relationship between the Froude number and the inertia terms of the momentum equation in the Saint-Venant equations, the relationship between Manning＇s roughness coefficient and water depth was obtained. Using the channel of the Huaihe River from Wangjiaba to Lutaizi stations as a case, to test the performance and rationality of the present flood routing model, the original hydraulic model was compared with the developed model. Results show that the stage hydrographs calculated by the developed flood routing model with the updated Manning＇s roughness coefficient have a good agreement with the observed stage hydrographs. This model performs better than the original hydraulic model.

Global Mission Sensitivity Study for Phased MissionSystem with Analysis of Variance Method

A comprehensive mission sensitivity analysis index based on Sobol's index called global mission sensitivity( GMS) was proposed in this paper which focused on analyzing the mission sensitivity of components of phased mission systems( PMS). The simulation strategy of GMS based on a Petri net and Monte Carlo method was presented which had broad applicability. Finally,the GMS and Birnbaum's sensitivity of components in a PMS example were compared. The GMS of component is demonstrated to be more adaptable to reflect the component mission sensitivity when the rated reliability parameters of components cannot be obtained, and components have state dependency or the system is subjected to common cause failure.

Development Progress of China’s First Mars Exploration Mission:Its Scientific Objectives and Payloads

China’s first Mars exploration mission is scheduled to be launched in 2020.It aims not only to conduct global and comprehensive exploration of Mars by use of an orbiter but also to carry out in situ observation of key sites on Mars with a rover.This mission focuses on the following studies:topography,geomorphology,geological structure,soil characteristics,water-ice distribution,material composition,atmosphere and ionosphere,surface climate,environmental characteristics,Mars internal structure,and Martian magnetic field.It is comprised of an orbiter,a lander,and a rover equipped with 13 scientific payloads.This article will give an introduction to the mission including mission plan,scientific objectives,scientific payloads,and its recent development progress.

基于SysML的载人登月可靠性安全性需求分析

为了将可靠性安全性分析融入基于模型的航天任务设计,也必须开展详细的可靠性安全性需求分析.首先,在从需求分解、系统设计的过程中,推导得出各层系统的可靠性安全性需求;结合系统正常需求,在完成系统顶层架构设计的同时,开展功能危害分析、故障树分析等,以验证各层的可靠性安全性需求;依据可靠性安全性需求及对其的验证情况,指导设计故障处置措施,完善系统设计.以美国阿尔忒弥斯载人登月任务设计为例进行了方法验证,为开展基于模型的载人登月系统设计与可靠性安全性一体化分析提供了一种方法.

ELECTRON SPIN RESONANCE DATING FOR THE AGE OF PEKING-MAN, LOC.1, ZHOUKOUDIAN, BEIJING

In this paper, we used ESR dating method to measure the accumulative dose of the fossil teeth samples, which are contemporaneous with the Peking-Man. The internal annual dose rate of samples are got by neutron activation analysis and the environmental annual dose rate by highly sensitive TL dosimeters to be embedded in cave deposits in the site. The results of ESR dating are corresponded with the dating results obtained by U-series, FT, TL and paleomagnetic stratigraphical methods on the 3rd, 4th, 7th and 10th layers. Calculation of using different models, the close-equilibrium model, the linear uranium accumulation model and radon loss-linear uranium accumulation model, for travertine, deer teeth and rhinoceros tooth, we obtained the age of the First Peking- Man in the nth layer is 578 ka and gave ages of other layers, from the 1st to the 13th layer in Peking- Man site.

The types and characteristics of man-induced sediment disaster

The man-induced sediment disaster includes material erosion, transportation and accumulation by human activities. It possesses special attribute in sociology and disaster science. In accordance with human activities, geomorphologic location, behavior and particular, the man-induced sediment disaster can be divided into 4 types: the drainage network, slope and gully, channel and plain-estuary-coastline. Each type includes erosion, transportation, accumulation, complexity and cascading. Based on human activity, geomorphology, sediment mechanics and catastrophology, the man-induced sediment disaster is characterized as follows: (1) accelerating tendency with geographical zoning back-ground; (2) non-order characters by blind action without special technical training; (3) gradually and sharply changing with human environment vibration; and (4) complexity and non-linear figure, etc. One of the reasons leading to man-induced sediment disaster is human environment vibration.

Anderson's Motives for Exploring Man's Frustration

Man's frustration is a dominant theme in Anderson's short stories.It is the condensation of his impressions of American life.His motives for exploring the problem include:to reveal the painful experience,feeling and situation of ordinary people during the economic,social and cultural transformations of America;to remind the reader of the choking effects of outworn conventional morality and the destructive effects of modern industrial materialism;to draw the reader's attention to the emotional life of the ordinary people;and to express his own views on and attitudes toward humanity and society.

A Man's Return to His First Hometown

A62-year-olddreambecamerealitywhenJosephS.FermtraveledhalfwayaroundtheglobefromtheUnitedStatestoChinatomeethischildhoodplaymatesinacountrytownineastChina'sShandongProvince.FermwasoneyearoldwhenhismissionaryparentssettledinLongshan.Theyleftin1936whenF...

Metallic Reserves of Submarine Manganese Nodules to be Estimated and Harnessed Prudently: Evidence from China's Jiaolong Manned Submersible

Since the discovery of oceanic manganese nodules during the expedition of the British ocean-going ship Challenger from 1872 to 1876, research and development for seabed manganese nodules have never ceased owing to the huge economic inducements. Manganese nodules are the black or dark brown, spherical or massive Mn-bearing ores, deposits of which are found on the sea bottom. The nodules are a mixture of silicate and insoluble potassium permanganates （also with sub-Ti, Fe and Na permanganates） that contain more than 30 kinds of metallic elements, among which those of greatest economic interest are Mn （27-30%）, Ni（1.25-1.5%）, Cu（1- 1.4%）, Co（0.2- 0.25 %）, Fe, Si, and AI, with minor amounts of Ca, Na, K, Ti, B, H and O.

Assessment of self- and cross-absorbed SAF values for HDRK-man using GEANT4 code: internal photon and electron emitters

The ultimate need to account for the partial amount of energy deposited in target tissue/organ resulting from internal inhalation,ingestion,and injection intakes of radionuclides,defined by the Medical Internal Radiation Dosimetry committee as the specific absorbed fraction(SAF),has become obvious.In this study,we assessed the SAF values for self-and cross-absorption,which were calculated for a uniform distribution of monoenergetic photon and electron emitters with energies ranging from 15 keV to 3 MeV.The voxelized human phantom‘‘High-Definition Reference Korean-man’’(HDRK-man),which was implemented using the Monte Carlo simulation code GEANT4(version 10.1),was used for several combinations of target–source organs.The results were compared to those of the International Commission on Radiological Protection Reference(ICRP133)and Zubal phantoms.It was found that the SAF values of the three models have a similar trend.However,the SAF values for the HDRK-man phantom were higher than those of the other two models,with a relatively good agreement with those for the ICRP133 phantom(differences of 13.9±2.8 and 12.1±3.2 for photon and electron emitters,respectively).To analyze the differences in SAF values,we calculated the chord length distributions(CLDs)for selected target–source combinations.The parameters of organ mass(or volume)and CLDs,in addition to the adopted computational procedures,mainly cause such discrepancies.For realistic radionuclide emission spectra,an overall overestimation was observed when computing the S values for three radiopharmaceuticals studied(I-131,In-111,and Lu-177)and for liver–spleen intra-and inter-organ absorption when compared with published data.The new arrangement of S and SAF values is expected to add value for multidisciplinary research and clinical communities.

A Comment on Frank O'Connor's Short Story "The Man of the House

This is moving story of a boy's growing up and of the deep love between Mother and

Undertaking the National and Historic Mission——New Year's Message for 2013

Spring is a vibrant and thriving season when everything looks fresh and new.In such a moment full of hope,I would like to give my best wishes to all the readers of International Understanding on behalf of CAFIU."The relationship between two countries relies on the friendly sentiments between their peoples".The friendly relationship between two countries is,in the final analysis,decided by the friendship between the two peoples.

Man’s Best Friend——Dog

在西方,人们通常将狗作为宠物来养,有些家庭养狗用以防盗。在牧羊区,人们则用牧羊犬来帮助牧民管理羊群。因此dog被称为人类最好的朋友(man’s best friend)。

One Man’s Charity Pursuit

When Lou Zongquan became a millionaire and thought his money was more than enough to sustain a kungfu school over 10 years ago, the engineer-turned-businessman decided it was time to feed his martial ambition. In less than a year, however, the kungfu fan found that his dream would lead him to running an orphanage.

One Man's Fight Against Coronary Heart Disease

Zhao Guoxin has the future all mapped out.First,he intends to turn the center into a full-time industry as a Sino-foreign joint venture com-plete with two pharmaceutical plants and a 200-bed hospital for coronary heart patients.This,he thinks,should take about three years.

Gyila:Tibet's First Senior Weather Man

There is no-one in the field of weather broadcasting in Tibet who does notknow about Gyila: Top 10 Youth of China, China’s Outstanding Scientist, winner of the 5th China Youth Scientific Progress, and winner of first May 4th Medal for Tibetan Youths.What people tell of him are legendary stories. Actually, he is an ordinary man who has cut a brilliant figure in work.