Semi-closed synthesis of nitrogen and oxygen Co-doped mesoporous carbon for selective aqueous oxidation

Heteroatom-doped meso/micro-porous carbon materials are conventionally produced by harsh carbonization under an inert atmosphere involving specific precursors,hard/soft templates,and heteroatom-containing agents.Herein,we report a facile synthesis of N and O co-doped meso/micro-porous carbon(NOMC)by template-free carbonization of a small-molecule precursor in a semi-closed system.The semi-closed carbonizaiton process yields hydrophilic NOMCs with large surface area in a high yield.The porous structure as well as the elemental composition of NOMCs can be modulated by changing the holding time at a particular temperature.NOMCs as metal-free heterogeneous catalysts can selectively oxidize benzyl alcohol and its derivatives into aldehydes/ketones with>85%conversion in aqueous solution,which is much higher than that of the control sample obtained in tube furnace(21%conversion),mainly due to their high N content,high percentage of pyridinic N,and large surface area.The presence of O-containing moieties also helps to improve the hydrophilicity and dispersion ability of catalysts and thus facilitates the mass transfer process during aqueous oxidation.The NOMC catalysts also dispayed excellent activity for a wide range of substrates with a selectivity of>99%.

Study on Deposition in Semi-Closed Coastal or Estuarine Harbour Basins

A preliminary study on the distribution of sediment transport and siltation within a semi-closed harbour as well as the factors affecting the siltation has been made with a suspended sediment model, in which the Lianyungang port is used as the prototype. Based on the work, this paper describes a tubid water experiment within a typical excavated harbour basin. According to the experimental results some expressions for predicting the average siltation amount for semi-closed harbour basins by means of dimensional analysis have been proposed, with tidal features, harbour geometry and properties of sediment taken into account. Through comparing the calculated results with the laboratory and field measured data, it has been shown that the expressions presented in this paper are reasonable.

Investigation on the Natural Modes of A Semi-Closed Floating Tank

Vessels with semi-closed tanks(i.e.,well docks)are widely applied in the military operation and maritime engineer-ing.The water is bound by the semi-closed floating tank and forced by both the incident waves and ship’s motions.The free surface oscillations inside the flooded well dock is thus distinctive and very complicated.So far,the natural modes of semi-closed floating tanks have not yet been studied.This paper investigates the characteristics of natural modes of a floating semi-closed tank by combining a mode-resolving model based on mild-slope equations and a hydrodynamic model based on computational fluid dynamics.Results show that the first three natural periods(i.e.,74,23.6,and 14 s)of the tank fall into the band of swell and infragravity waves and they could be triggered under certain circumstance.Multi-period free surface oscillations are observed inside the tank,including the longest natural period(i.e.,74 s),though the incident waves are monochromatic.A possible generation mechanism for the long-period mode is explained on the basis of liquid sloshing and harbor oscillations.Moreover,a long-period component with a period close to the natural mode of well dock is observed in the ship motions,which is generated by the interaction between the waves and ship.

Quantitative method for calculating spatial release region for laser-guided bomb

The laser-guided bomb(LGB)is an air-to-ground pre-cision-guided weapon that offers high hit rates,great power,and ease of use.LGBs are guided by semi-active laser ground-seek-ing technology,which means that atmospheric conditions can affect their accuracy.The spatial release region(SRR)of LGBs is difficult to calculate precisely,especially when there is a poor field of view.This can result in a lower real hit probability.To increase the hit probability of LGBs in tough atmospheric situa-tions,a novel method for calculating the SRR has been pro-posed.This method is based on the transmittance model of the 1.06μm laser in atmospheric species and the laser diffuse reflection model of the target surface to determine the capture target time of the laser seeker.Then,it calculates the boundary ballistic space starting position by ballistic model and gets the spatial scope of the spatial release region.This method can determine the release region of LGBs based on flight test data such as instantaneous velocity,altitude,off-axis angle,and atmospheric visibility.By more effectively employing aircraft release conditions,atmospheric visibility and other factors,the SRR calculation method can improve LGB hit probabi-lity by 9.2%.

赓续“两弹一星与马兰精神”

深情追忆尚一穷二白的我国,在国际霸权主义等敌对势力封锁打压下,艰辛崛起并倔强发展自主的核科学与技术及国防科技工业的峥嵘岁月。刻骨铭心那1964年10月16日罗布泊大漠中马兰核试基地的东方巨响,击破了超级大国的核垄断。紧接着自力更生顽强拼搏赢得“两弹一星”等“当惊世界殊”科技奇迹是何等的壮丽辉煌!这全靠党中央果断决策与英明领导,一群中华民族的优秀儿女勇于担当起国之脊梁,艰苦奋斗干惊天动地事,无私奉献做隐姓埋名人,舍生忘死成就了我国核大国地位。矢志报国而埋头苦干铸造共和国核盾牌的“两弹一星”元勋和英雄的万千马兰将士,当彪炳史册而感召后人。在当下新时代,全社会都必须无比坚定赓续与脚踏实地践行“两弹一星与马兰精神”,为振兴中华的伟大历史使命恪尽职守砥砺前行。这尤其对于从事核科学与技术及其各领域广泛应用,以及为发展核科技及其应用保驾护航的放射防护学等有关各界,特别深感格外亲切和使命光荣与责任重大。

防爆服装冲击防护性能测评技术研究进展

为提升防爆服装冲击防护性能评估的准确性,综述了近些年国内外关于服装冲击防护性能测评技术及方法的研究现状。在明确现役防爆服装构成及其冲击防护性能评估内容的基础上,分析了当前爆炸实验、等效载荷实验、数值仿真3类测评方法的特点与不足;从测试方法的差异因素和局限2个角度,分析了不同测试条件、测试对象设置对防爆服装冲击防护性能测评结果的影响;对比总结了相关表征及评价指标的应用范围、优缺点。最后指出在未来的研究中,应全面准确地模拟真实爆炸冲击载荷环境、考虑人体真实着装防护状态,并构建完善的冲击防护性能评价体系,以提高防爆服装冲击防护性能测评的准确性。

SEQUENTIAL DISPERSING DISTRIBUTION EFFECT OF AERIAL CLUSTER BOMB

The sequential dispersing results of aerial cluster bomb are discussed. The ballistic model and the mod- el for impact point distribution of bullets are established. The main factors influencing impact point distribution are analyzed by numerical simulation. And the feasibility of improving distribution effect through sequential dis- persing is validated. Sequential dispersion and optimized airdrop parameters can help to achieve better battle effec- tiveness.

基于姿态估计的滑翔类制导炸弹目标的未来点预测方法

滑翔类制导炸弹已经成为要地防空面临的重要威胁,如何精准预测该类型目标轨迹及未来点是现代防空火控解算的关键问题。提出了一种基于姿态估计的滑翔类制导炸弹目标未来点预测方法。首先,在目标现在点估计的基础上,推算出目标姿态坐标系,并在姿态坐标系受力分析的基础上,建立目标机动平面;然后,在机动平面内建立阻力、升力可迭代的动力学微分方程;最后,将机动平面内获取的预测点转换到状态估计坐标系获取最终结果。实验结果表明,相较于传统方法,该方法对目标未来点的预测精度提高了37.2%~65.5%,对滑翔类制导炸弹目标的轨迹预测更加有效。

Epidemiology of civilian blast injuries inflicted by terrorist bombings from 1970-2016

An upsurge of terrorist activity has occurred in the past two decades. As part of this, explosive devices continue to be extensively deployed against civilians in wide-ranging environments. Bombings remain the leading worldwide cause of civilian fatalities due to terrorism. This demands an understanding of modern terrorist bombing trends to inform mitigation strategy. The objective of this study was to identify the occurrence and severity of bombings against civilian targets in diverse attack settings, and to establish corresponding blast injury profiles. Data was obtained from analysis of the Global Terrorism Database(GTD) and a meta-analysis of blast injury data derived from the PubMed database. Closed environment explosions were associated with significantly greater(p<0.05) mortality than in open spaces. The injury profiles were found to be influenced by attack setting, with higher rates of primary injury on trains and buses, and secondary injury in open space.

Using the Haddon matrix to explore medical response strategies for terrorist subway bombings

Background:Since the 1970 s,terrorist bombings in subways have been frequently occurring worldwide.To cope with this threat and to provide medical response countermeasures,we analyzed the characteristics of subway bombing terrorist attacks and used the Haddon matrix to explore medical response strategies.Methods:First,we analyzed 111 subway bombings from 1970 to 2017 recorded in the Global Terrorism Database to provide a reference for the strategy exploration.Then,we convened an expert panel to use the Haddon matrix to explore the medical response strategies to subway bombings.Results:In recent decades,at least one bombing attack occurs every 3 years.Summarized by the Haddon matrix,the influencing factors of medical responses to conventional subway bombings include the adequacy of first-aid kits and the medical evacuation equipment,the traffic conditions affecting the evacuation,the continuity and stability of communication,as well as the factors exclusively attributed to dirty bomb attacks in subways,such as ionizing radiation protection capabilities,the structure of the radiation sickness treatment network based on the subway lines,and the disposal of radioactive sewage.These factors form the basis of the strategy discussion.Conclusions:Since subway bombings are long-term threats,it is necessary to have proper medical response preparation.Based on the Haddon matrix,we explored the medical response strategies for terrorist subway bombings,especially dirty bomb attacks.Haddon matrix can help policymakers systematically find the most important factors,which makes the preparations of the response more efficient.

Underwater explosion effects of 60 mm H.E. mortar bomb on a cylindrical concrete structure-PIT

PIT tests are usually performed when a mass distribution of High Explosive(H.E) projectile fragments is required. This paper shows the underwater detonation effects of 60 mm, M90 H.E. mortar bomb filled with Comp. B on cylindrical concrete structure(concrete pipe closed at one end-similar to a PIT test)which is 2 m high(inner height) with inner diameter of also 2 m. Thickness of both wall and bottom of a pipe is 0.35 m. Detailed characteristics of concrete which is used for manufacturing of a pipe are specified. Mortar bomb is submerged directly in to the water(no free airspace around the bomb) with the nose pointing to the bottom of a pipe. Number and mass of fragments after detonation are presented by table and photographs. Fragments of dummy fuze, through which blasting cap was protruded, are collected and reassembled to form a shape of a fuze after detonation where expanding of fuze material due to a detonation products is visualized. After underwater detonation, detonation of the same mortar bomb is performed in an empty pipe and the effects of this kind of detonation are observed. Distance at which fragments generated from submerged mortar bomb will not reach concrete pipes wall is also determined.

Bombings specific triage(Bost Tool) tool and its application by healthcare professionals

BACKGROUND: Bombing is a unique incident which produces unique patterns, multiple and occult injuries. Death often is a result of combined blast, ballistic and thermal effect injuries. Various natures of injury, self referrals and arrival by private transportation may lead to "wrong triage" in the emergency department. In India there has been an increase in incidence of bombing in the last 15 years. There is no documented triage tool from the National Disaster Management Authority of India for Bombings. We have tried to develop an ideal bombing specific triage tool which will guide the right patients to the right place at the right time and save more lives.METHODS: There are three methods of studying the triage tool: 1) real disaster; 2) mock drill; 3) table top exercise. In this study, a table top exercise method was selected. There are two groups, each consisting of an emergency physician, a nurse and a paramedic.RESULTS: By using the proportion test, we found that correct triaging was significantly different(P=0.005) in proportion between the two groups: group B(80%) with triage tool performed better in triaging the bomb blast victims than group A(50%) without the bombing specific triage tool performed.CONCLUSION: Development of bombing specific triage tool can reduce under triaging.

Numerical study on the case effect of a bomb air explosion

When considering the bomb explosion damage effect,the air shock wave and high-speed fragments of the bomb case are two major threats.In experiments,the air shock wave was studied by the bare explosives superseding the real cased bomb;in contrast,the bomb case influence was ignored to reduce risk.The air explosion simulations of the MK84 warhead with and without the case were conducted.The numerical simulation results showed that the bomb case significantly influenced the shock wave generated by the bomb:the spatial distribution of shock wave in the near field changed,and the peak value of shock wave was reduced.Breakage of the case and kinetic energy of the fragmentation consumed 3 and 38% of the explosion energy,respectively.The increasing factors of the peak overpressure induced by the bare explosive on the ground and in the air were 1.43-3.04 and 1.37-1.57,respectively.Four typical stages of case breakage were defined.The mass distribution of the fragments follows the Mott distribution.The initial velocity distribution of the fragments agreed well with the Gurney equation.

Preparing for a “dirty bomb” attack: The optimum mix of medical countermeasure resources

Background: In radiological emergencies with radionuclide incorporation, decorporation treatment is particularly effective if started early. Treating all people potentially contaminated("urgent treatment") may require large antidote stockpiles. An efficacious way to reduce antidote requirements is by using radioactivity screening equipment. We analyzed the suitability of such equipment for triage purposes and determined the most efficient mix of screening units and antidote daily doses.Methods: The committed effective doses corresponding to activities within the detection limits of monitoring portals and mobile whole-body counters were used to assess their usefulness as triage tools. To determine the optimal resource mix, we departed from a large-scale scenario(60,000 victims) and based on purchase prices of antidotes and screening equipment in Germany, we calculated efficiencies of different combinations of medical countermeasure resources by data envelopment analysis. Cost-effectiveness was expressed as the costs per life year saved and compared to risk reduction opportunities in other sectors of society as well as the values of a statistical life.Results: Monitoring portals are adequate instruments for a sensitive triage after cesium-137 exposure with a high screening throughput. For the detection of americium-241 whole-body counters with a lower daily screening capacity per unit are needed. Assuming that 1% of the potentially contaminated patients actually need decorporation treatment, an efficient resource mix includes 6 monitoring portals and 25 mobile whole-body counters. The optimum mix depends on price discounts and in particular the fraction of victims actually needing treatment. The costeffectiveness of preparedness for a "dirty bomb" attack is less than for common health care, but costs for a life year saved are less than for many risk-reduction interventions in the environmental sector.Conclusion: To achieve economic efficiency a high daily screening capacity is of major importance to substantially decrease the required amount of antidote doses. Among the determinants of the number of equipment units needed, the fraction of the potentially contaminated victims that actually needs treatment is the most difficult to assess. Judging cost-effectiveness of the preparedness for "dirty bomb" attacks is an issue of principle that must be dealt with by political leaders.

Estimation of radiation-induced health hazards from a“dirty bomb”attack with radiocesium under different assault and rescue conditions

In the case of a terrorist attack by a“dirty bomb”,blast injuries,external irradiation and the incorporation of radioactivity are to be expected.Departing from information about the radiological attack scenario with cesium-137 in the U.S.National Scenario Planning Guide,we estimated the radiological doses absorbed.Similar calculations were performed for a smaller plume size and a detonation in a subway.For conditions as described in the U.S.scenario,the committed effective dose amounted to a maximum of 848 mSv,even for very unfavorable conditions.Red bone marrow equivalent doses are insufcient to induce acute radiation sickness(ARS).In the case of a smaller plume size,the ARS threshold may be exceeded in some cases.In a subway bombing,doses are much higher and the occurrence of ARS should be expected.The health hazards from a dirty bomb attack will depend on the location and the explosive device.The derived Haddon matrix indicates that preparing for such an event includes education of all the medical staff about radiation effects,the time lines of radiation damages and the treatment priorities.Further determinants of the outcome include rapid evacuation even from difficult locations,the availability of a specific triage tool to rapidly identify victims at risk for ARS,the availability of an antidote stockpile and dedicated hospital beds to treat seriously irradiated victims.

On the continued acceleration of bomb casing fragments following casing fracture

It has been said that,once a bomb casing has fractured, "detonation gases will then stream around the fragments or bypass them,and the acceleration process stops there." However,while apparently copious gas flow through casing fractures indicates some pressure release,it is also an indication of significant gas drive pressure,post casing fracture.This paper shows two approaches to the problem of calculating the actual loss of drive.One presents first-order analytical calculations,in cylindrical geometry,of pressure loss to the inside surface of a fractured casing.The second shows the modelling of a selected example in the CTH code.Both approaches reveal that gas escape,while occurring at its own soundspeed relative to the adjacent casing fragments,has to compete with rapid radial expansion of the casing.Together with some historic experiments now publicly available,our calculations indicate that post-fracture casing fragment acceleration is,for most systems,unlikely to be reduced significantly.

A Preliminary Study on the Spherical Bombs(Huolei)of the Southern Song Dynasty,Unearthed in Chongqing

The military situation of the thirteenth century required that the Song and the Mongols construct a great number of defensive works,relying on the mountains or facing the rivers,in the mountainous Sichuan Province and Chongqing.In recent years,a special kind of explosive firearms,huolei火雷(bombs),was unearthed in the large-scale excavations of the site of Diaoyu Fortress钓鱼城in Hechuan District合川and the Baidicheng白帝城in Fengjie County奉节,both of which were defensive works constructed in this mountainous area during the Southern Song dynasty.In addition,the ruins of kilns and the clay molds that were relevant to the casting of iron huolei have been discovered at the site of Baidicheng,indicating that these huolei might have been produced locally.The Southern Song iron huolei unearthed in Chongqing are the most direct evidence of the evolvement of gunpowder and firearms,and are of great significance to the history of science and technology,in particular the history of military technology.

Feng Jiasheng’s Diagrams of Iron Bombs(Huopao)and Beyond:On the Academic Significance of the Southern Song Iron Bombs(Huopao)Unearthed in Chongqing

The world’s earliest bomb with an iron casing,the iron huopao鐵火砲(cast-iron bomb,also referred to as zhentian lei震天雷,literally“thunder-crash bomb”),is one of the most important inventions of ancient China relating to gunpowder and firearms.Until recently,however,academics were not able to conduct substantial research on the topic,as no actual remains of a huopao had yet been found.Since 2013,in the excavation of two sites of Southern Song ancient cities(Diaoyu Fortress and Baidicheng)in Chongqing,archaeologists from the Chongqing Cultural Heritage Research Institute have discovered a number of iron huopao of the Southern Song dynasty.This finding not only provides first-hand material for research on the history of the invention of gunpowder and firearms,which has always been lacking,but also offers new physical evidence for an exploration of the history of war and the military history of the thirteenth century(in particular the Mongol-Song war),and is thus historically significant.

Medical management of victims contaminated with radionuclides after a “dirty bomb” attack

A wide spectrum of scenarios may lead to radiation incidents and the liberation of radioactive material. In the case of a terrorist attack by a "dirty bomb", there is a risk of mechanical and thermal trauma, external irradiation, superficial contamination and incorporation of radioactive material. The first treatment priority must be given to the care of trauma patients with life-threatening injuries, as the health effects of radiation occur with latency. Radionuclide incorporation will lead to a longer-lasting irradiation from inside the body, associated with a higher risk of stochastic radiation effects(e.g., occurrence of tumors) in the long run. It must be expected that victims with potentially incorporated radionuclides will far outnumber trauma patients. The elimination of radionuclides can be enhanced by the administration of decorporation agents such as(Ca) Diethylenetriaminepentaacetic acid(DTPA) or Prussian blue,reducing the radiological burden of the body. There is still no consensus whether decorporation treatment should be started immediately based only on a suspicion of radionuclide incorporation("urgent approach") or if the results of internal dosimetry confirming the necessity of a treatment should be awaited, accepting the delay caused by the measurements and computations("precautionary approach"). As the therapeutic effectiveness may be substantially decreased if treatment initiation is delayed only by several days, depending on the radionuclide, the physicochemical properties of the compounds involved and the route of absorption, we favor an "urgent approach" from a medical point of view. In doubt, it seems justified to treat victims by precaution, as the adverse effects of the medication seem minimal. However, in the case of a high number of victims, an "urgent treatment approach" may require a large number of daily doses of antidotes, and therefore, adequate investments in preparedness and antidote stockpiling are necessary.

Earthquakes induced by deep penetrating bombing

The data of M≥5 earthquakes occurred in one year before and after 4 deep penetrating bombs in the region within 500 km and 1 000 km from the shooting site are presented. The 4 bombs are those happened in 1999 Kosovo of Yugoslavia, the 1991 Baghdad of Iraq, the 2001 Tora Bora of Afghanistan, and the 2003 Kirkuk of Iraq, respec-tively. The data indicate that the deep penetrating bombs may have remotely triggered some earthquakes. The deep penetrating bombs in seismically active regions should be forbidden.