基于Mini-Diver的降水头试验在砂砾石层的应用

对格尔木某拟建水库工程坝址区河床的深厚砂砾石层进行钻孔注水试验,在钻孔的各试段同时进行常水头和基于Mini-Diver的降水头注水试验。钻孔注水试验结果表明,基于Mini-Diver的降水头试验在深厚砂砾石层应用上是可行的,而且试验方法更优于常水头注水试验。对于渗透系数较大的地层,采用该方法不仅大大缩短试验时间,而且能获取大量的观测数据和观测水头下降的整个过程,计算的砂砾石层渗透系数也更符合实际。

血栓抽吸联合替罗非班治疗急性ST段抬高性心肌梗死患者冠脉内血栓病变的疗效观察

目的探讨血栓抽吸联合替罗非班治疗急性ST段抬高性心肌梗死患者冠脉内血栓病变的疗效。方法42例急性ST段抬高性心肌梗死患者随机分为血栓抽吸+替罗非班组和标准经皮冠状动脉介入治疗(PCI)组,观察两组PCI术前、术后心肌梗死血栓溶解(TIMI)积分、球囊扩张次数、TIMI血流、无复流或慢血流、校正的TIMI帧计数(cTFC)、心肌灌注分级(MBG)、手术时间、术后左心室射血分数(LVEF)及住院期间出血并发症与包括死亡、再发心肌梗死、再次血运重建等的主要心血管不良事件(MACE)发生情况。结果血栓抽吸+替罗非班组与对照组相比治疗后血栓积分明显下降,球囊扩张次数减少,支架直接植入率高,最后TIMI血流改善,cTFC降低,MBG改善;左室射血分数显著高于对照组,两组住院期间的MACE发生率及出血并发症比较差异无显著意义。结论血栓抽吸与替罗非班联合治疗可改善急性ST段抬高性心肌梗死患者冠脉内血栓病变的血栓负荷、冠状动脉血流、心肌灌注和左室收缩功能,而不增加患者住院期间主要并发症的发生。

Evaluation of genetic diversity in short duration cotton(Gossypium hirsutum L.)

Background: Cotton(Gossypium hirsutum L.) is an important fiber crop in Bangladesh. Genetic diversity among the genotypes of a germplasm has a great importance for cotton breeding. An experiment was carried out at the experimental field of Cotton Research, Training and Seed Multiplication Farm, Sreepur, Gazipur during the cropping season of 2015-2016 with 100 genotypes to evaluate genetic diversity of cotton genotypes for short duration using field performance.Results: The genotypes under study were grouped into ten clusters through multivariate analysis using GENSTAT-5.Cluster III contained maximum number of genotypes(16) while cluster X contained the least number of genotypes(7).The inter cluster distances were larger than intra cluster distances in all cases suggesting wider genetic diversity among the genotypes of different clusters. The maximum and minimum inter cluster distances were observed between clusters II and V(10.78) and clusters VIII and IX(3.30), respectively. The results indicated diverse and close relationship among the genotypes of those clusters. Earliness index, single boll weight and days to boll opening showed the higher contribution to the genetic divergence among 19 characters.Conclusion: Based on the results of genetic diversity and earliness index, the genotypes from cluster Ⅱ could be used as parent in hybridization program for the development of short duration cotton variety.

Diver自动水位记录仪在抽水试验求参中的应用

为了测试Diver自动水位记录仪在抽水试验求参中的应用效果,在北京房山琉璃河地区进行了抽水试验,比较了Diver与测绳获取的抽水试验原始数据特点,利用Diver数据计算了水文地质参数。整个抽水试验全过程,Diver监测与人工实测的主孔数据平均差值为0.17m,副孔平均差值0.02m。据Diver数据,最终确定该区域的水文地质参数:渗透系数k为91.51m/d、导水系数T为1555.72m2/d、储水系数S为0.0314。Diver自动水位记录仪具有数据连续、数据量大和准确性高等优势,从数据来源上确保了求参结果的合理性。

替罗非斑联合Diver血栓抽吸导管介入治疗对急性心肌梗死患者心肌再灌注的作用

目的探讨替罗非斑联合Diver血栓抽吸导管在冠脉介入治疗中对急性ST段抬高型心肌梗死患者心肌再灌注的作用。方法选取行经皮冠状动脉介入治疗(percutaneous coronary intervention,PCI)的急性ST段抬高型心肌梗死患者84例,所有患者均经冠脉造影确诊合并冠脉血栓,按照完全随机数字表法分为观察组和对照组各42例。对照组患者在PCI术中给予Diver血栓抽吸导管介入治疗,观察组患者在PCI术中应用DiverCE血栓抽吸导管抽吸联合替罗非班进行治疗。两组再根据情况选择合适支架置入或经球囊预扩张后置入支架,观察并记录两组患者90min内ST回落、校正TIMI帧数计数(CTFC)、手术前后冠脉血流情况、不良心血管事件以及术后出血相关并发症。结果两组患者90min内ST回落、CTFC差异明显(p<0.05),但观察组患者90min内ST回落明显高于对照组(p<0.05),而CTFC明显小于对照组(p<0.05)。经秩和检验,两组患者术前TIMI血流分级差异不明显(u=0.59,p>0.05)。两组患者术后TIMI血流分级差异明显(u=6.75,p<0.05)。两组患者心脏猝死、非致命性心肌梗死发生率比较无明显差异(p>0.05)。对照组患者反复缺血性心绞痛发生率为19.0%,观察组患者反复缺血性心绞痛发生率为2.4%,明显低于对照组(X2=5.44,p<0.05)。观察组患者再灌注心律失常发生率明显低于对照组(p<0.05)。两组患者牙龈出血、穿刺点血肿、尿潜血、大便潜血、总出血发生率差异无统计学意义(p>0.05)。结论替罗非斑联合Diver血栓抽吸导管介入治疗能有效改善急性心肌梗死患者血流灌注,但并不增加患者出血风险,值得临床推广应用。

Cross-Layer Adaptive Resource Allocation Algorithm with Diverse QoS Requirements for Single-Cell OFDMA Systems

The orthogonal frequency division multiple access( OFDMA) based communication system has been considered as the main trend of next-Generation communication system. But the existing resource allocation algorithm designed for such system is always with high complexity thus hard to be realized. To solve such problem with the constraints of spectrum efficiency and buffer state,a novel cross-layer resource allocation algorithm( RAA) is proposed in this paper. The goal of our RAA is to maximize the system throughput while satisfying several practical constraints,such as fairness among services,head of line( Ho L) delay and diverse quality of service( Qo S) requirements. Due to these constraints,finding the optimal solution becomes a NPhard problem. Therefore in this paper a novel method to solve such problem with acceptable complexity is proposed within following steps: firstly,based on the link state we formulate the ideal subchannel allocation strategy as a convex optimization problem,which can be efficiently solved by our proposed lagrange multiplier technique subchannel allocation( LMTSA) algorithm; secondly,according to the obtained channel allocation matrix,a power allocation algorithm based on the water-filling power allocation( WPA) idea is deployed to get the optimal power allocation matrix combining with adaptive modulation and coding( AMC); finally,through a greedy algorithm,the ultimate subchannel and power allocation matrix can be obtained based on iterative method. The simulation results illustrate that we can achieve the higher throughput and better Qo S performance than the widely-used maximum throughput( MT) algorithm and round robin( RR) algorithm.

An inexpensive underwater mine countermeasures simulator with real-time 3D after action review

This paper presents the results of a concept capability demonstration pilot study, the aim of which was to investigate how inexpensive gaming software and hardware technologies could be exploited in the development and evaluation of a simulator prototype for training Royal Navy mine clearance divers, specifically focusing on the detection and accurate reporting of the location and condition of underwater ordnance. The simulator was constructed using the Blender open source 3D modelling toolkit and game engine, and featured not only an interactive 3D editor for underwater scenario generation by instructors, but also a real-time, 3D After Action Review(AAR) system for formative assessment and feedback.The simulated scenarios and AAR architecture were based on early human factors observations and briefings conducted at the UK's Defence Diving School(DDS), an organisation that provides basic military diving training for all Royal Navy and Army(Royal Engineers) divers. An experimental pilot study was undertaken to determine whether or not basic navigational and mine detection components of diver performance could be improved as a result of exposing participants to the AAR system, delivered between simulated diving scenarios. The results suggest that the provision of AAR was accompanied by significant performance improvements in the positive identification of simulated underwater ordnance(in contrast to non-ordnance objects) and on participants' description of their location, their immediate in-water or seabed context and their structural condition. Only marginal improvements were found with participants' navigational performance in terms of their deviation accuracies from a pre-programmed expert search path. Overall, this project contributes to the growing corpus of evidence supporting the development of simulators that demonstrate the value of exploiting open source gaming software and the significance of adopting established games design techniques in delivering highly engaging scenarios to defence training communities.

Development of underwater wet welding experimental and divers training system

Compared to traditional welding methods, the underwater wet welding is special with many different characteristics due to the unique aqueous environment. It is conducted completely under water by divers and unique welding technology is required in the special operation environment. The operating levels of the divers are the key factor to acquire high quality welded joints. In this paper, an underwater wet welding experimental and divers training system is developed to serve divers training and conducting welding experiments. The system consists of life support system, signals real-time monitoring system and communicating system, etc. An underwater butt welding experiment based on welding electrodes is conducted, and the system works well. It proves that the system can guarantee divers welding safely and successfully and high quality weld seam is expected to be acquired.

浅析3G网络优化方法

随着3G正式商用的临近,3G网络的规划和优化越来越被关注。从网络优化的目的出发,阐述了无线网络优化的流程及方法,并重点介绍了网优中的可调参数,为3G网络优化方法论提供了参考。

上海邮票会历任会长考略(上)

迄今为止未见有《上海邮票会会史》之著述面世,而早期会务资料曾遭劫难,据朱世杰撰文《上海邮票会二十五周纪念记》透露：＂不幸是年（1925年）春季,该会书记狄浮司君（W.C.Divers）家内失慎,历年会务记录,悉付一炬,惜哉。＂因此对百年前创办的上海邮票会尚存不少疑团有待破解,历任会长情况即为问题之一,迄今邮界描述或语焉不详、或以讹传讹。

ON THE TRANSPLANTATION AND CULTIVATION OF KAPPAPHYCUS ALVAREZII IN CHINA

A 2-year study on Koppophycus alvorezii (Doty )Doty introduced to Hainan Island from the Philippines in 1985 showed promising results.The average daily growth in weight reached 10% at a favourable temperature of about 26℃. Experimental results showed that timely cutting of the plant was an effective way to obtain new cuttings for cultivation and accelerate growth. New cuttings 0.05 kg in weight are suggested to be used as " seeds" and the old plant should be harvested. At present, artificial cultivation with a type of underwater raft applicable in places where there is strong wind will expand cultivation to more regions in Hainan Province.

Qualification Test for the Reliability of Diver Gas Recovery System

A qualification test for the reliability of a newly-developed Diver Gas Recovery System (DGRS) was carried out in the Naval Medical Research Institute of the People's Liberation Army, China from March 29 to April 2, 1995. A sequential test plan of high discrimination ratio for the mean time between failures (MTBF) was adopted. The test procedures simulated those of a 300 msw dive. A hyperbaric breathing machine was used for the simulation of diver's respiratory functions. Parameters, such as diving depth, respiratory minute volume (RMV), CO2 production, gas flow rate, partial pressure of carbon dioxide, and ambient temperature and himidity were all displayed and recorded with a microcomputer system. The results indicated that no failure occurred during the 91.5 h operation. According to the acceptance and rejection criteria specified in the statistical test plan, a no-failure score in the 88 h operation is acceptable. Therefore, the DGRS has been demonstrated to meet the requirements of MTBF specified in the contract.

Underwater Diver Image Enhancement via Dual-Guided Filtering

The scattering and absorption of light propagating underwater cause the underwater images to present lowcontrast,color deviation,and loss of details,which in turn make human posture recognition challenging.To address these issues,this study introduced the dual-guided filtering technique and developed an underwater diver image improvement method.First,the color distortion of the underwater diver image was solved using white balance technology to obtain a color-corrected image.Second,dual-guided filtering was applied to the white balanced image to correct the distorted color and enhance its details.Four feature weight maps of the two images were then calculated,and two normalizedweightmapswere constructed formulti-scale fusion using normalization.To better preserve the obtained image details,the fusion image was histogram-stretched to obtain the final enhanced result.The experimental results validated that this method has improved the accuracy of underwater human posture recognition.

Manned Testing of the Diver Gas Recovery Installation

The Diver Gas Recovery Installation (DGRI) was evaluated at 80 msw saturation - 100 msw excursion diving on HeO2 in the Naval Medical Research Institute (NMRI) of China in April, 1995. The diving depth, lockout time, breathing gas flow rate and consumption, inspired oxygen partial pressure (PO2) and carbon dioxide partial pressure (PCO2) were monitored. The results indicated that PO2 was controlled to fluctuate from 64.3 to 84.0 kPa and PCO2 went up from 0.01 kPa up to O.I kPa during 4 hours excursion diving; recovery of breathing gas reached 95%; three divers felt well and breathed comfortably during simulating heavy work. The test showed that it met desired performance goals. The DGRI is a kind of important equipment for long duration deep dive. It enables the gases exhaled by the divers to be re-cycled, and therefore it has great social, military and economic significance for diving operation and submarine rescue.

Problems Related to Divers Health and Comfort in Hyperbaric He-O_2 Environment

The Diver Gas Recovery System(DGRS)is an important accessory equipment of the 300m Saturation Dive System. The system facilitates the recycling of the breathing gases for divers,therefore,it has great economic benefits. In April 1995, a 300 m unmanned test and a 100 m manned test on the HY2031 DGRSwere carried out successively.Ten months later,another manned test on the HY2032 DGRS

Handover Mechanism Based on Underwater Hybrid Software-Defined Modem in Advanced Diver Networks

For the past few decades,the internet of underwater things(IoUT)otained a lot of attention in mobile aquatic applications such as oceanography,diver network monitoring,unmanned underwater exploration,underwater surveillance,location tracking system,etc.Most of the IoUT applications rely on acoustic medium.The current IoUT applications face difficulty in delivering a reliable communication system due to the various technical limitations of IoUT environment such as low data rate,attenuation,limited bandwidth,limited battery,limited memory,connectivity problem,etc.One of the significant applications of IoUT include monitoring underwater diver networks.In order to perform a reliable and energy-efficient communication system in the underwater diver networks,a smart underwater hybrid softwaredefined modem(UHSDM)for the mobile ad-hoc network was developed that is used for selecting the best channel/medium among acoustic,visible light communication(VLC),and infrared(IR)based on the criteria established within the system.However,due to the mobility of underwater divers,the developed UHSDMmeets the challenges such as connectivity errors,frequent link failure,transmission delay caused by re-routing,etc.During emergency,the divers are most at the risk of survival.To deal with diver mobility,connectivity,energy efficiency,and reducing the latency in ADN,a handover mechanism based on pre-built UHSDM is proposed in this paper.This paper focuses on(1)design of UHSDM for ADN(2)propose the channel selection mechanism in UHSDM for selecting the best medium for handover and(3)propose handover protocol inADN.The implementation result shows that the proposed mechanism can be used to find the new route for divers in advance and the latency can be reduced significantly.Additionally,this paper shows the real field experiment of air tests and underwater tests with various distances.This research will contribute much to the profit of researchers in underwater diver networks and underwater networks,for improving the quality of services(QoS)of underwater applications.

A pioneering survey of deep-diving and off-shore cetaceans in the northern South China Sea

A pioneering boat-based survey was conducted in 2019,to gather baseline information regarding the presence,composition,relative abundance,and spatial distribution of deep-diving and off-shore cetaceans in the northern South China Sea(SCS).A total of 27 sightings comprising at least 8 cetacean species were recorded during the 13-day survey,including 5 deep-diving species(i.e.Risso’s dolphin[Grampus griseus],short-finned pilot whale[Globicephala macrorhynchus],sperm whale[Physeter macrocephalus],Cuvier’s beaked whale[Ziphius cavirostris],and an unidentified beaked whale[either the ginkgo-toothed beaked whale,Mesoplodon ginkgodens,or Deraniyagala’s beaked whale,Mesoplodon hotaula]),as well as 3 off-shore dolphins(i.e.pantropical spotted dolphin[Stenella attenuate],striped dolphin[Stenella coeruleoalba],and Fraser’s dolphin[Lagenodelphis hosei]).With the exception of pantropical spotted dolphins,all other species were sighted and recorded at sea in the northern SCS for the first time.The pantropical spotted dolphin was the most frequently sighted species,comprising 30%of the total sightings.Deep-diving cetaceans were mainly sighted in the northern Xisha Archipelago,whereas off-shore dolphins were distributed across the survey area.The pantropical spotted dolphin was observed in aggregations of more than 100 individuals and nearly all encountered species included calves;these findings suggested that the survey area functions as an important feeding and calving ground for various cetacean species.This pioneering survey provides fundamental information regarding cetacean fauna in the northern SCS and highlights the need to strengthen research and conservation efforts concerning these species.

九零后的PADI你不懂

子子孙孙,活着为了赚钱吃饭,吃饭为了活着赚钱,就不能干点与这无关的事吗?我们可不可以略微做点无用的事,不为升学不为赚钱甚至不为陶冶情操,就是为了浪费?端午放假前,我家小孩要求说,他想趁假期去菲律宾的长滩岛学习潜水,考一个PADI证书回来。什么?PADI是什么玩意?出国考研能加分吗?美国英国留学承认吗?找工作有帮助吗?小孩看我一脑门黑线,怜悯地瞪了我一会儿,发给我一个网址。原来,PADI是Profesional Association of Diver Instructor(国际专业潜水教练协会)的英文缩写,这个机构基于潜水的特殊教学需要,设计出一套完整的教学系统。网上说,

Springboard to Success China’s top woman diver sets out to make a big splash at the Beijing Games

Four years ago,Guo Jingjing, the young diving queen could have retired at the prime of her career.She had nothing left to prove.Back then,she was already a legendary athlete.She had competed in three Olympics,pocketing two

THE GREAT UNDER WATER WALL

Scuba diving at China’s most famous monument is an adrenaline rush not to be missed潜入水下雄关要塞,名副其实'游'长城For centuries,the Great Wall symbolized the edge of civilization;precariously perched on sweeping mountainsides and barren plains,the wall seemingly echoes the untamed spirit of the wild north.